Talk:Equalization

types of equalizers
I think that there needs to be some serious editing on the overview. and to move the classifications of an equalizer into other catergories.

here is a suggestion:

The classifications of an equalizer are determined by the method it changes the tone and it's functionality.

tone control methods
 * shelving
 * passing
 * peaking
 * cut and boost

functionality
 * sweeping
 * parametric
 * graphic
 * paragraphic

Ab2kgj 03:33, 3 January 2006 (UTC)

misc
Could someone please give a technical overview of why nine-band equalizers are better for tweaking speakers than non-multiples-of-three band equalizers? Electrosoccertux 03:10, 3 July 2006 (UTC)

There is nothing magical about a multiple-of-three bad equalizer. Indeed, there is nothing special about nine-band equalizers. Most pros use a graphic eq with at least 30 bands. --Pjvpjv 12:14, 4 July 2006 (UTC)

there are two possible reasons : multiples of three fit more closely with the fact that music is arranged in octaves. or most likely that the internal components are more suited to a multiple of three arrangement. — Preceding unsigned comment added by 193.1.172.163 (talk • contribs) 13:15, 4 August 2006


 * A 31 band Equalizer is the standard. It brakes down what the human ear can hear into 1/3 octave intervals.  The logic behind this is that due to how the ear works.  We, in theory, can not fully distinguish the difference in sounds if they are closer than 1/3 octave from each other.


 * (side note) most Pro audio engineers use parametric EQs as they let you get in closer than the 1/3 octave ones.    — Preceding unsigned comment added by 24.153.172.210 (talk) 03:19, 16 October 2012 (UTC)


 * (DLC 15 OCT 2012) — Preceding unsigned comment added by 24.153.172.210 (talk) 03:20, 16 October 2012 (UTC)

history to add

 * something about Baxendall
 * something about George Massenburg

Iain 01:37, 31 July 2006 (UTC)

Merge
I agree to merge with equalization filter.--Lenilucho 19:47, 11 August 2006 (UTC)
 * I vote to keep the articles seperate. This one should discuss the piece of audio equipment while the other should ultimately be expanded to include an explination of various digital algo's and analog circuits to actually do the work. The other should be linked to in this article. 48v 03:56, 7 November 2006 (UTC)

Wrong Link
the link for high pass links to a Lord of the Rings ArticleTjb891 16:01, 16 August 2006 (UTC)
 * I fixed it and the rest of the filter's links.--Lenilucho 18:44, 16 August 2006 (UTC)

Sense
Does "In passing through any channel, data is temporal/frequency spreading occurs. " make sense? --82.25.174.136 19:16, 24 November 2006 (UTC)
 * I think that was meant to mean that channel distortion is seen in both the time-domain and the frequency-domain, however, the article has been changed and no longer says that. Time-domain distortion is a result of differential time-delay at different frequencies and the consequent change in phase relationships.  Time-delay and phase distortion are issues with long telecom lines, but not usually with mixing desks which is what this article seems to be primarily about.  Feel free to put that in though.  Sp in ni  ng  Spark  10:06, 20 September 2008 (UTC)

Telephone crosstalk
I have put a fact tag on this statement which I do not believe to be true;


 * Telephone companies use equalization to reduce bleed-through or crosstalk between adjacent telephone wires

Crosstalk may certainly be reduced by the band-pass filter, but as the article says earlier, a filter performing complete rejection of a band is not an equaliser. The main defence against crosstalk in telecoms is to maintain the balance of the circuit through the use of balanced lines, repeating coils and balanced topology in the filter and amplifier designs. None of which has anything to do with equalisers.

I think the whole paragraph should be removed from the article but I have asked here first before any drastic deletion.  Sp in ni ng  Spark  10:26, 20 September 2008 (UTC)

Equalization that only equalizes, balances or neutralizes
I took out the lead paragraph that stated equalization could only mean the use of filters to return an out-of-balance system to a balanced or neutral state. That's what the concept involved originally but as soon as users obtained the tool which could adjust frequency response, the artistic use of the tool to create a non-linear response became just as, or more, important. Binksternet (talk) 07:27, 31 December 2008 (UTC)


 * Trimming the lede is good, but I think it should still say that the original meaning was to equalize flat. It is inaccurate to imply the artistic use was almost immediately taken up: the concept of equalization was developed and first applied in the 1920s, it was much later (1960s?) that equalizers were used artistically.  This is an encyclopedia after all, not a glossary of modern jargon.  I also have a problem with your reference (Ballou) in which I could not find anything to back up your definition of equalization as "altering" rather than "flattening".  What is the exact quote? I found this on page 1034: In other words, by this philosophy, equalization has very little to do with the room and a flat-response loudspeaker system will eliminate the need for extensive equalization in many cases which implies that Ballou's definition is just the opposite.  It could also be mentioned that equalization does not just apply to amplitude, phase is important as well for instance and also dates back to the 1920s.  Also came across "directivity equalization" in Ballou on page 426.  Sp in ni  ng  Spark  11:29, 31 December 2008 (UTC)


 * In my first edition 1987 copy of Ballou, the definition appears on page 571, chapter 17 "Filters and Equalizers", section 17.1 where it states "An equalizer is a device consisting of reactive elements that may be connected into an electrical circuit for the purpose of altering the frequency characteristics of that circuit either up or down." I expanded Ballou's 20-year old definition to include digital equalization, and I took out the 'reactive elements' and 'electrical circuit' that appeared to me to limit the definition to the analog world. The word he used--'altering'--allows for either the neutralization of non-linear system responses or the artistic practice of changing the frequency response for aesthetic reasons.


 * Indeed I do intend to say that users immediately began to use equalization filters for other than equalizing the response to be linear. One very early task in which EQ was employed was trimming excessive low and high frequencies that would overmodulate a medium. Another was to achieve a mids-forward vocal intelligibility curve for film sound reproduction.


 * I agree that the original meaning should be brought back into the article's lead. Clearly, equalization for the purpose of flattening response is still with us in many respects, and a number of equalizer products such as the classic cut-only UREI graphics stand in evidence of their primary use to flatten room response in critical listening spaces. I'll take a stab at it with the goal of preserving the dignity and value of the first equalization concepts along with describing the continued service of that model. Maybe I'm imagining too much detail for the lead... Anyway, my experience with EQ is 100% audio, so feel free to jump in and correct/add anything I'm missing related to non-audio equalization.


 * The reason I struck the previous lead paragraph is that it defined simple bandpass/bandstop or shelving filters as filters, restricting them from being termed "equalization". Modern usage universally allows a single such filter to be called EQ.


 * Phase is indeed important, and has been critical in achieving EQ for many years. Some modern digital and analog filters purport to get their results without affecting phase, so phase change isn't entirely necessary. Binksternet (talk) 16:53, 31 December 2008 (UTC)


 * Had a stab at that, plus I have done the refs in a slightly different way with page numbers - hope that's ok.  Sp in ni ng  Spark  20:29, 31 December 2008 (UTC)


 * Ref style is good but I'm not yet happy with the flow of the lead. I've got some ideas I'm mulling... and some more refs. Binksternet (talk) 20:56, 31 December 2008 (UTC)


 * Binkster and Spark,


 * At the top of this Talk page it says, "This article may be too technical for a general audience." You guys have made it even more  technical.  Let's help readers who are new to the subject by explaining the origin of the term "equalization."    And that means starting out by explaining what, exactly, is being made more equal:  the frequency response of a signal-processing system in various portions of the frequency spectrum.  [No need to argue about whether this is the "original" meaning, or a later meaning: the root of the word "equalization" is "equal," from Latin "aequus," meaning  even or level.   Let's not try to redefine that!]


 * It's OK to mention that equalizers can be used for an artistic effect, but we should point out that when this is done, it likely results in unequalization, not equalization.199.46.170.96 (talk) 20:36, 2 January 2009 (UTC)


 * I thought that Birkenstet's reworked lead was clean, precise and to the point, at the same time removing a lot of confusing meandering. Feel free though, to suggest alternative or additional wording.  The meaning of the Latin root is not of any great significance, many words in English have a meaning different, or even contrary, to the meaning of the root.  For instance, there is sophisticated, awful and alcohol.  The tag at the top of the page, and other tags like it, normally go at the top of the article page to attract the attention of a copyeditor, not here on the talk page.  I had assumed it had got moved here after the problem was dealt with.  But as I say, if you think you have some ideas for making the article easier to read for beginners, then please help.
 * On the question of describing artistic use as unequalization, not sure at all if that is right, at the very least a reference is required describing it as such. A couple of examples by analogy: adjusting the colour balanc of an image until it is rendered as a grey-scale would be viewed as producing a neutral image.  Measuring the light intensity with scientific instruments at each wavelength, however, would reveal a spectrum that was anything but flat.  On the other hand, a pectrum that was set to be flat with instruments would be percieved as highly coloured by human vision.  Second example: tuning a musical instrument to the tempered scale means setting the pitch for each semitone at equal intervals as measured with a scientific instrument.  Musicians, however, refer to this scale as chromatic because it sounds "coloured".  To set a scale a musician would hear as "neutral" requires the notes to be set a little off this scale to well known whole number ratios.  In a very similar way, it is perfectly valid to describe adjusting the frequency response of a speaker system till it "sounds right" as equalization.  The result may well not be a flat response as measured by scientific instruments, but it is so to the human ear.  Sp in ni  ng  Spark  19:43, 3 January 2009 (UTC)

How to hook up
I am setting up a home thetre set up. In the stack where does the equalizer go How connected..... Thanks —Preceding unsigned comment added by 71.161.157.15 (talk) 12:57, 18 May 2009 (UTC)


 * A better place to ask questions is WP:Reference desk/Science. This page is for discussing improvements to the article.  Sp in ni  ng  Spark  22:14, 18 May 2009 (UTC)

RIAA-EQ
Wouldn't it be relevant to at least link to the article on RIAA equalization, as I'm sure many new gramophone enthusiasts would appreciate a direct reference to hooking up their record players correctly? 93.166.114.170 (talk) 13:59, 10 November 2009 (UTC)


 * If new gramophone enthusiasts can't find this information on the internet, they don't deserve to listen to vinyl platters. None of them need know about equalization; they just need to find a receiver with a phono input which already contains the circuit. Binksternet (talk) 15:40, 10 November 2009 (UTC)

Merge parametric and blind equalization into equalization article
Someone coming to wikipedia to get a sense of what equalization is won't get very far without addressing parametric equalization. You have to go into detail about parametric equalization in the equalization article if you're to discuss equalization at all. The two articles will likely end up being very redundant.

It seems pretty arbitrary that parametric and blind equalization have separate articles while other types (graphic, rotary, shelf, transversal) don't. Is either article lengthy enough or either topic sufficiently distinct to merit separate pages?

Discuss.--Atlantictire (talk) 04:31, 11 September 2010 (UTC)


 * I support the Parametric equalizer merge. This merge will help complete this Equalization article. --Kvng (talk) 15:53, 2 February 2011 (UTC)


 * I oppose the Blind equalizer merge. A more appropriate merge destination for this is Equalization filter. --Kvng (talk) 15:53, 2 February 2011 (UTC)


 * One more for good measure - I've added Smiley face curve into the mix for merger. I suppose it has enough to stand on its own, but certain elements at least could be added into the mix. DJSparky    huh?  00:45, 26 September 2010 (UTC)


 * I removed your Smiley face curve merge notice after four months of no discussion. Binksternet (talk) 15:54, 1 February 2011 (UTC)


 * I have restored it and created an new discussion section below. The lack of discussion was possibly due to the fact that the discussion links in the merge banners were not set up properly. --Kvng (talk) 15:53, 2 February 2011 (UTC)

I oppose merging the parametric equalizer article here because they have different intentions. Parametric equalizers (in the sense the term is heard) has to do with professional audio equipment and one very specific application of equalization. I'd expect an article on "equalization" to cover the topic in a more general sense, as it partly does (but it also tends to emphasize audio equalization: the graphic equalizer section should be offloaded into a separate article, perhaps with minimal mention in this article). "Equalization" and "filtering" are general concepts. Graphic and parametric equalizers are particular pieces of audio equipment. And blind equalization is also a separate concept in regards to figuring out the proper equalization to use given a received signal. These are all rather distinct. If anything, merge the graphic and parametric equalizers into one article on (perhaps) "audio equalizers" (and include smiley faced curve there too). Leave "equalization" more abstract mentioning some applications including audio. Interferometrist (talk) 19:31, 13 March 2011 (UTC)


 * This makes a certain amount of sense to me as a final outcome. I had assumed that this article was all about audio and that Equalization filter covered the borader topic. But, how about we deal with this one step at a time. Let's get a nice single article about audio equalization built. I don't really care what we name it. That article sould include most of what's in this article plus what's in Parametric equalizer and Smiley-face curve. --Kvng (talk) 14:57, 15 March 2011 (UTC)


 * I agree that there should be an article discussing only audio-frequency equalization and that it should cover the subject broadly. I do not agree that the other articles must be merged into this notional audio equalization article; it can discuss the various forms of equalization without diving into deep detail. Here's the hierarchy I picture:
 * Equalization filter
 * Equalization (audio) (discussing shelving, HPF, LPF, graphic, parametric, notch, sweepable, automatic, etc)
 * Graphic equalizer
 * Smiley face curve
 * Parametric equalization
 * RIAA equalization
 * British EQ
 * That's my view. Binksternet (talk) 15:40, 15 March 2011 (UTC)

I actually hadn't even seen the current Equalization filter article when I spoke before, but now see that its content needs to be merged into the future article Equalization (audio) that you both have proposed. I could make the issue a little more complicated though: Graphic equalizer (not yet written), Smiley face curve, Parametric equalization, and British EQ all have to do with what I'll call "Music equalization" (for lack of a better term). This includes sections 1 and 2 of the current Equalization filter along with possible future articles tone controls, loudness control (combine with Smiley face), speaker equalization etc. Oh, I'm certainly not saying that these need to be separate articles, but could as well be topics in one article (except that a few of these already exist separately). The article should mention that "equalization" is a misnomer (but has become the accepted term) since these are typically used to modify the tone to suit someone's taste, not strictly to compensate for a channel's frequency response.

Then there should be an article which discusses actual channel equalization (or some such term) which WOULD include section 3 of Equalization filter (Telecommunications lines), RIAA equalization, FM pre/de-emphasis as well as equalization of non-audio channels; this is the orginal meaning of "equalization"). Such equalizers are generally non-adjustable (by a user, at least) and transparent to the end user. So I call it a different subject, even when it IS audio. Anyway, I don't have much time to deal with this nor am I the best person to write about the specialized issues regarding either professional audio or channel equalization problems. (Though I'd be very happy to review what is written and check for errors and missing issues. Come to think of it, I don't have to ask for permission ;-) Interferometrist (talk) 16:49, 15 March 2011 (UTC)
 * Looking at it a bit further, I now see there is a Category:Tone, EQ and filter which seems to mainly include matter which I called "music equalization" and what the new Equalization (audio) article would overview. (Though a few articles there don't belong in this catagory). Again, I'm not good at organizing all of this, but agree with Kvng and Binksternet  that these topics should be covered at a higher level, eliminating excessive redundancy, and then either a higher level article considering equalization filter technology in general or just one covering channel equalization in general. Right now, (as is typical) some of the subtopics and applications are totally missing and others are covered multiply and should be consolidated. Interferometrist (talk) 17:25, 15 March 2011 (UTC)


 * Talk will only get us so far. There's plenty of room for improvement in this set of articles. I encourage WP:BOLDNESS. --Kvng (talk) 04:50, 16 March 2011 (UTC)
 * You got it.
 * Equalization
 * Equalization filter(discussing shelving, HPF, LPF, graphic, parametric, notch, sweepable, automatic, etc)
 * Equalization (audio) (for now User:Atlantictire/Equalization (audio)--Atlantictire (talk) 03:50, 23 April 2011 (UTC)

Making the EQ article more accessable to civilians
This discussion is a continuation of discussions on the User talk:Atlantictire and User talk:Spinningspark pages.


 * Sorry. I don’t mean to sound combative. I have a rather dry sense of humor that doesn’t always translate well in type. Only, if you wanna see Hulk turn green, start calling Johnny Marr fans the “lowest common denominator”. (I kid).


 * In all seriousness though, anyone who is seriously interested in performing and recording music, be they Johnny Marr fans, Arto Lindsay fans, or Taylor Swift fans, is likely to find their way to the EQ page. I did, and I would like to break down this granite wall of geek. For all of us.


 * What I don’t want to do is create a separate article on EQ specific to recording, because the information would be incredibly redundant. Such a page would just talk about parametric eq, graphic eq, shelf eq, high pass, low pass. Everything already covered in this article. A subsection on recording within the EQ article would probably suffice.


 * Here are some things WP:LEAD stipulates that I think my lead does that the previous lead did not:


 * Addresses why the subject is notable.
 * I talk about everyday uses of eq, such as stereos, radios, and sound recording.


 * Avoids specialized terminology
 * I don't use terms like "passive filter", "active filter", and "phase equalization"


 * To quote that page “The subject should be placed in a context with which many readers could be expected to be familiar. For example, rather than giving the latitude and longitude of a town, it is better to state that it is the suburb of some city, or perhaps that it provides services for the farm country of xyz county. Readers should not be dropped into the middle of the subject from the first word; they should be eased into it.”


 * So to reiterate, like it or not, this subject is of interest to the tech illiterate. Great interest. I would like to help make it accessible to them without giving short shrift to essential information.


 * Please help me do this. Brief descriptions of other notable uses of EQ in the lead, such as telecommunications, would be wonderful. Also, a summary of the different kinds of EQ. I will try to write this, but feel free to correct glaring inaccuracies.--Atlantictire (talk) 20:26, 11 September 2010 (UTC)


 * I have reworked the opening, which was still saying that equalisation was only about audio, but have kept the focus on sound. There were also some technical errors, I could not make out what was meant by changing the distance between frequency peaks - that means changing the frequency to my mind which is not what equalisers do.  There are still some things that need addressing - equalization is not giving equal energies to all frequencies, that is wrong.  One might make all frequencies of a test signal equal, but the energy distribution of the signal depends on the source as much as the channel.  It is the response of the channel that is equalised, not the signal.  Phase equalisation also needs putting back in, this is actually more important than amplitude equalisation in many applications, but it may be better to introduce it in terms of time-delay equalisation.  Sp in ni  ng  Spark  20:27, 17 September 2010 (UTC)
 * Spinningspark, your last edit was outstanding. I'm sure these aren't always easy concepts to explain to laymen and you did it beautifully. A few questions: 1.) What exactly is phase equalization? Aligning frequencies so that they are "in phase" with each other? Would you mind improving the explanation of this on the Phase (waves) page, since it is currently defined with an equation? 2.) What do you mean by "equalizing the response of the channel"? --Atlantictire (talk) 22:42, 17 September 2010 (UTC)


 * Phase-equalization and time-delay equalization are very much related and can be explained in terms of each other. Time-delay first: it is possible that the frequencies composing a signal can take different times to get to the destination (microphone to loudspeaker say).  This will distort the waveshape; a signal that started out as a square wave (say) will not be a square wave when it arrives at the loudspeaker.  This is because harmonics in the square wave are out of phase with the fundamental, and each other, because they are experiencing different delays.  This is not so serious an effect with audio, but audiophiles will nevertheless tell you they can hear the difference, and it is particularly noticeable with square wave test signals.  For a television waveform, however, it is disasterous, rendering the signal completely useless, and it must be equalised.  Equalisation is achieved with a bank of filter sections, much as amplitude equalisation is achieved, the only difference is that phase/delay equalisation requires all-pass filters rather than low-pass, band-pass and high-pass.  Another important application is stereo sound lines.  As I said, delay of some frequencies is not so important for audio, but for stereo it is important that the left and right channel remain in phase otherwise the stereo image is destroyed.  There can be a delay for the high frequencies, but it is important that the delay is exactly the same for the left and right channel.
 * Equalising the response of the channel. The "channel" is all the equipment, cable and transmission lines that the signal has to pass through.  There will be some attenuation of the signal as it passes through, but likely the attenuation will not be the same at all frequencies.  Equalisation makes the attenuation the same at all frequencies, this is why it is called equalisation.  This is not the same as making all frequencies the same energy.  As an example, a piece of music might consist of some bass notes being played very loudly plus some very quiet singing, lets say loud 100 Hz and quiet 500 Hz.  The idea is to get that signal to the loudspeaker in exactly the condition it was created.  So if the 500 Hz gets attenuated a bit in the channel, equalisation should raise it back up to correct.  It is not the purpose of equalisation to amplify the 500 Hz up to the same level as the 100 Hz, that would be completely distorting the original piece of music.  Equalisation raises or lowers the level by exactly the same amount regardless of what the signal is doing - the equaliser will be doing exactly the same thing to the signal (provided it is not adjusted in the meantime) if it were the 500 Hz which were loud and the 100 Hz which were quiet.  Think of this also; in the example piece there is no signal at a frequency of 200 Hz.  That frequency cannot possibly be raised up to the same energy level no matter what settings you put on the equaliser because the frequency simply doesn't exist in this piece.  Sp in ni  ng  Spark  01:58, 18 September 2010 (UTC)
 * Thank you for that explanation. I've been busy editing other articles, so I'm just now getting the chance to puzzle through it. Again, excellent edits to the lead. I hope you don't mind that I added some links for specialized terminology and made very minor edits to the prose. Very nice explanation of phase shift on the phase page too.--Atlantictire (talk) 05:45, 22 September 2010 (UTC)
 * Your last edit had said something about making the response of the system flat from end to end.--Atlantictire (talk) 00:48, 23 September 2010 (UTC)

Smiley face merge
I fixed some dead discussion links for the proposed merge from Smiley face curve to this article. We should (re)start the discussion.


 * I support a merge. The Equalization article is incomplete. --Kvng (talk) 15:29, 2 February 2011 (UTC)
 * It looks like you are imagining a panoramic EQ article which covers the topic broadly and completely. Is that the case? What we have now are a bunch of smaller subtopic articles as satellites to the larger one. I can see arguments for having both the very large EQ article and the subtopic satellites, for extra detail such as listing a number of individual examples of smiley face curves. Binksternet (talk) 20:20, 2 February 2011 (UTC)
 * What you're talking about is WP:SUMMARY. Normally this is used when an article on a broad subject grows too big. Would you argue that the topic is potentially large enough to eventually merit summary style and so might as well start off that way? --Kvng (talk) 22:18, 2 February 2011 (UTC)
 * Yes, summary style main article, covering equalization broadly but not too deeply. Binksternet (talk) 23:01, 2 February 2011 (UTC)
 * Summary style is used for broad topics. Equalization is not clearly so broad. Summary is usually invoked once an article becomes too large. This article plus all the articles proposed to be merged into it would not add up to something large enough to merit summary style. --Kvng (talk) 14:25, 3 February 2011 (UTC)

Oppose -- see my remarks above under "Merge parametric and blind equalization into equalization article." Interferometrist (talk) 19:34, 13 March 2011 (UTC)

Botched merge
This so-called merge seems to be turning into a campaign to delete everything not understood by someone who only knows how to adjust their own car stereo equaliser. The very first edit in this sequence has taken out the history of the graphic equaliser with the edit summary "streamlined prose, took out history because it was hopelessly stuffed with undefined jargon". This is completely unacceptable, history of technology is exactly the sort of thing that an encyclopedia should be all about. Doubtless it could be improved, but deleting because one cannot immediately grasp what is being said is outrageous. Extreme caution is called for when editing a subject one does not understand, not reckless boldness. I then skipped up to the edits in the telecomms section since I have an interest in that field and found chunks had been deleted with no explanation at all in the edit summary. I appreciate that the aim is to turn this article into summary style, but if the telecomms information is too detailed for this page it should be moved to a new page and linked, not simply deleted out of hand.

I am not going to look at the rest of the edits right now - it would be a lot of work and this has made me angry enough already. Please give an explanation why I should not revert this whole sorry mess back to the pre-merge baseline which is exactly what I am inclined to do. A detailed plan of how the deleted information is going to be identified and restored (or else an explanation of why it should not be anywhere on Wikipedia) might dissuade me from doing this.  Sp in ni ng  Spark  11:13, 23 April 2011 (UTC)
 * Detailed plan: translate the information you thought was unjustly deleted into plain English and put it back in the article. It's easy enough to retrieve. Just remember: this is an encyclopedia, not a textbook, and this page is an introduction to the topic of equalization. It needs to be relevant to people who aren't already intimately familiar with the subject.
 * It looked like back in March there was agreement that a general article on equalization and an article on equalization specific to audio applications ought to be created. So, let's do that.--Atlantictire (talk) 11:27, 23 April 2011 (UTC)
 * No, let's not do that. I am ok with more detailed stuff being moved to a more specific article.  I am absolutley not ok with the first move in this process being a wholesale deletion of material provided by many editors over many years with no visibility of the deleted material existing on Wikipedia.  There was no consensus at all to do this.  There is no tracking of what has been deleted, no discussion on this page of the passages to go.  I want to see the replacement text first, not take it on trust that it will get back one day after suitable processing.  Please put a stop to this now.  Sp in ni  ng  Spark  15:54, 23 April 2011 (UTC)
 * This appears to be an argument about method, that the target articles should be fleshed out before the summary article is stripped of text. I agree that it is better for the reader to have the information available in two places at once (for a short time) rather than having it deleted (for a short time). Binksternet (talk) 16:14, 23 April 2011 (UTC)
 * The EQ article in its present state a total mess. You've got the lead which gives you a decent notion of what EQ is but overly emphasizes sound production; a cursory, not very well organized discussion of filters; a random wordy bit on graphic equalization and then some verbose, poorly organized information on applications that gets overly bogged down in jargon and excessive detail. And the equalization filters article is practically an exact duplication of information already in this article. Many people such as myself come to this page because they are trying to figure out what EQ is and in its present state it is entirely unhelpful save for the lead.
 * I see no reason not to revert this article back to the state it was in after the merge and put the earlier versions of the equalization and equalization filters in a sand box. That way, Spinningspark can return information he feels is essential and non-experts stand a changes of being able to read the thing.--Atlantictire (talk) 16:44, 23 April 2011 (UTC)
 * Also, there is now an Equalization (audio) article which renders much of the info in the Equalization article redundant. Through my edits I was merely trying to carry out what the editors of this page had appeared to agree should be done. I would appreciate it if you read my final edit to this page and related what is objectionable terms of organization, concision and usefulness to the general public. http://en.wikipedia.org/w/index.php?title=Equalization&diff=425474311&oldid=425470689 --Atlantictire (talk) 17:14, 23 April 2011 (UTC)
 * (ec) This is precisely what I am objecting to. You want carte blanche to remove whatever you like and leave to others the tedious work of picking through your edits to discover what you have deleted and find a new home for it - is that a fair summary?  Sorry, you need to do that yourself, if you want to break out part of the article then fine by me, but it is not actually all that long and all the previous discussion was about merging, not removal.  Three editors took part in the discussion, one of whom opposed and the other two proposed something utterly different to what you are doing - hardly a consensus.  No one is opposing article improvement, that is a straw man argument.  What I am opposing is blind deletion of any factual material.  Either the material should be moved to another page on Wikipedia (before deleting anything here) or else it should be discussed on this page and consensus achieved that it does not belong on Wikipedia.  Sp in ni  ng  Spark  17:24, 23 April 2011 (UTC)
 * I assure you I did not "blindly" delete anything... only information that was redundant or presented with unlinked, undefined terminology that was unfathomable to those who did not already know what equalization is. I'm sorry, but the onus is on you to write text that is intelligible to non-specialists. I would happily have left the information in if it had been.
 * It still sounds as if you are unhappy because of information deleted from sections on history and uses. If you can re-write it with better clarity then I see no reason not to include it. But I am afraid that is your task, not mine.--Atlantictire (talk) 17:51, 23 April 2011 (UTC)
 * Deletion is not the usual response to poorly written text. A more uncontroversial action is to tag the text with an appropriate template, or even improve it yourself.  Just because you do not understand a section of text does not mean that it is "unfathomable" and could not be improved.  Sp in ni  ng  Spark  18:32, 23 April 2011 (UTC)

Revert the merge revert
Here is the condition of the article post-merge: http://en.wikipedia.org/w/index.php?title=Equalization&diff=425474311&oldid=425470689

Much of the information on equalization as it relates to sound recording and processing was moved to the Equalization (audio) article.

It is my opinion that it is better to have a well-organized, intelligible article to which information can be added than a random accretion of poorly organized information which needs to be entirely reworked. The changes made in the merge were wholly based on the discussions above, and the only articles affected were Equalization and Equalization filter, as the purpose and content of both were nearly identical: broad overviews of equalization applications and concepts.

User Spinningspark believes that the articles should remain in their pre-merge condition because of information that was deleted from sections on history and applications. As I have explained above, this information was either moved to the new Equalization (audio) page or deleted because it was redundant or written using undefined, unlinked terminology intelligible only to specialists. I see no problem with Spinningspark including this information so long as 1.) he can specifically identify which text he objects to having been deleted and 2.) re-write the text for a general, not specialist, audience. As I have said many, many times before wikipedia is an encyclopedia... not a textbook. It exists for laymen to find introductory information presented in clear, concise, readable prose.--Atlantictire (talk) 18:55, 23 April 2011 (UTC)


 * Sorry, I wrote the following before your latest remarks (which I'll consider) and hit an edit conflict, so I'll paste them in now while I can.....

Hi, I hadn't actually contributed to this page at all so maybe I have less right to judge, but I'll throw in my 2 cents. I took a good look at the last version by Atlantictire alongside the previous (now reverted to) version. The proposed version (of Atlantictire) is a nicer read in many ways and closer to what this article should probably look like. However:
 * While a lot of material deserved to be cut, some of the trimming was a bit reckless as Spinningspark pointed out. That is, the editor wrote from his own knowledge but appeared to cut a lot of useful material simply because he couldn't appreciate it.
 * His version has a number of technical errors (the old one did too, but not as many) such as separate sections on "pass filters" and "shelving filters" (identical) and his concept of all other equalization being based on "peaking filters" -- not the best distinction (though I understand how he is thinking about this, but such a classification is dubious) or his description of bandpass filters. However I'd be willing to look after remaining technical errors after there's some consensus on a version, but I think Atlantictire was a bit hasty in these changes.
 * Removal of the history bits from the main text was welcome since those detracted from the flow, but that means there should have been a history section or footnotes or something, not wholesale removal.

I have some other issues with what I've seen. He started a new article now called Equalization (audio). That's funny, I thought the Equalization article WAS about audio, only, in its current form! It even says so:
 * This article is about frequency-dependent processing of audio signals.

Of course a lot of equalization has nothing to do with audio, but other applications, however those are less visible (not a piece of gear you can buy at a stereo/music equipment store) and are totally ignored by the article (and perhaps need to be if no one feels like writing about them. The Linear filter article encompasses them at least in a formal sense). I don't understand the difference between the two articles or where this is going. And actually I find the Equalization (audio) article a little bit better and could just as well become the "Equalization" article itself (except for the other problems that have been noted). Why two almost identical articles? Unless there is some real intention to add non-audio equalization to the one (in which case it needs VERY much work which I doubt anyone will do). Are we going to keep parametric equalization as a separate article? (It does have a lot of more detailed content). If so, why not a separate article on graphic equalizers? This doesn't make sense.

But I'll look at this more and help with a technical review after the scope of the article(s) is nailed down. - Interferometrist (talk) 19:26, 23 April 2011 (UTC)
 * Interferometrist, thank you for your input. In the past Spinningspark and others have made the case that equalization has many applications, so in depth information pertaining to sound processing and recording specifically ought to go in an EQ audio article. I tend to agree with their arguments.


 * I'm an optimist, so I don't see why an adequate, general article on equalization couldn't be created... especially if there are extant articles on the relevant concepts and applications. Thoughts? Perhaps Interferometrist and others could create an outline for such an article.


 * Did not realize I was making an error by creating separate categories for shelving and pass filters. Sorry. Seems like an easy enough fix. Have at it!


 * The history section was an absolute train wreck. Some of it has been moved to Equalization (audio). The rest was amorphous gibberish and was deleted because nothing could be done with it in its current state.
 * Amorphous gibberish like the name of the company which first used slide controls and the name of the engineer and company which first made a true graphic equaliser you mean? All of which was cited information by the way.  But I see you have still found room for that nonsense about smiley faces so that must be ok then.  Sp in ni  ng  Spark  20:58, 23 April 2011 (UTC)


 * I don't think there's any good reason for there being an article on parametric equalization and not graphic equalization. The parametric equalization article seems bloated and superfluous, so I'd be fine merging it into Equalization (audio).--Atlantictire (talk) 20:27, 23 April 2011 (UTC)


 * The other direction, articles for both graphic and parametric EQ, seems like a good way to go. Binksternet (talk) 00:00, 24 April 2011 (UTC)
 * Ok, you have fun with that. In the meantime I'm a week away from reverting the revert. This article has been a shambles for years, and I'm tired of people throwing tantrums whenever changes are made to it. If you're not actively attempting to make it a serviceable overview of equalization but are loudly complaining, I don't have much sympathy for you. Help come up with an outline of what you think a proper article on equalization should include because what exists now is an embarrassment.--Atlantictire (talk) 00:13, 24 April 2011 (UTC)
 * That would not be a good idea without first getting consensus on this page. Try instead addressing the issues raised.  Sp in ni  ng  Spark  08:13, 24 April 2011 (UTC)

I received this request from Atlantictire:
 * Since you seem to know as much about the subject as anyone, I am VERY much in favor of your making an outline of what a general article on equalization might look like. I'd like the pages pertaining to basic sound recording and processing concepts to be intelligible to your average non-engineer music fan who comes across terms like "EQ".....

Well I sort of apologize but I instead turned my attention to the EQ (Audio) article because it was an easier task because of my familiarity with the subject, but further because "Equalization" is just TOO broad (if it were really to cover the subject, not just audio) and frankly I'm not so familiar with non-audio applications (but very well understand the math describing them). So I haven't done what Atlantictire asked, and again I'm not sure who is going to round up material on equalization outside of audio -- or I should say outside of professional audio/hi-fi/music (the EQ (audio) article focus) whereas telephone line EQ (although still audio frequencies....) IS properly addressed in the EQ (general) article since it really IS EQUALIZATION (as the term was meant) and not "tone modification" which is what audio "eq" means in practice. I'm not sure how these should all be organized so I'm just telling you what I have done so far and I really don't have time to attack the bigger problem (hell, I didn't even have time to do the work I did on the EQ (audio) article, but did anyway;-). Perhaps the EQ (general) article should be very simple refering to various applications (including audio/hi-fi) with their separate articles, but probably most of those don't (and won't) exist. I see there are pages on "Delay equalization" and on "RIAA equalization" (which again is audio but not one with a user control which are what the EQ (audio) article addresses).

Although I understand that Spinningspark was upset because of the haste and deleted material, I do think Atlantictire worked hard and did make two articles out of one both of which were more readable than the original, and so I'm happy to be starting from the one he called EQ (audio) without figuring out right now how these will all get organized together. But the EQ (general) isn't very general (nor was Atlantictire's version, now reverted) so these still need merging or diverging if you will. - Interferometrist (talk) 14:41, 24 April 2011 (UTC)

Oh by the way, I'm sorry but I read and spoke too soon. I see that "pass filters" are not exactly the same as shelving filters but had never heard the term (nor do I think it's understandable) but rather low-pass, hi-pass, bandpass (the generalization of which I hadn't heard). Or they ARE shelving filters with the cut extended to zero. I'll try to work on these sections now....

Oh, since EQ (audio) is a split-off article for now, please don't revert what I'm writing (no one's going to see it anyway!) but do improve the wording, exposition etc. Also, is the lede way too long? I can't summarize things much tighter without feeling that I left out an important aspect or over-over-simplified the issues. Interferometrist (talk) 14:54, 24 April 2011 (UTC)


 * Don't forget all-pass filters, too. Binksternet (talk) 15:22, 24 April 2011 (UTC)


 * Well I haven't forgot about them, but now this gets again into the scope of the various articles. No mixing board or stereo system contains an all-pass filter that someone could or would possibly want to adjust, since the effect isn't audible (a few audiophile snobs will disagree). I also didn't mention bandpass filters since they are not used as such, though as the previous version pointed out using a high cut and low cut can be construed as a very low-Q bandpass filter, but I rather pointed out the converse. (But band cut and band boost could well describe the response of a parametric equalizer, but now that is equalization again, not cutting signals as much as possible). In other words classical hi/low pass filters are NOT to BALANCE audio, but to ELIMINATE some frequencies completely (as well as possible with an Nth order filter) which I sort of see as different, though they are both called EQ. And a notch filter may well be used in equalization -- I did forget that, but can better be mentioned perhaps in the section on parametric equalizers which can implement that function. At least that's my take.... are we on the same page?


 * And if there will be a more general eq article then that could/should mention all-pass filters and refer to the delay/phase equalization article at the very least since that would include applications (digital communications channels etc.) where waveform, not just frequecy response, is important. And maybe there are audio applications requiring delay equalization (underwater telephone cables?) but again this isn't part of sound equipment one would purchase (is it??). Interferometrist (talk) 16:29, 24 April 2011 (UTC)


 * Oh by the way, since you work more closely in the field I'm hoping you (Binksternet) can give me feedback on any fine (or not-so-fine) points I may have stated poorly (or wrongly!). And of course feedback from the others is welcome too, in addition to figuring out (as we still need to) which article is going to address which subjects in which detail in relation to which others (did I say that right?) -- Interferometrist (talk) 16:51, 24 April 2011 (UTC)


 * Typical equalization circuits work by making changes to phase response to yield a change in frequency response. The all-pass filter which only changes phase response—no boost or attenuation of frequency—is offered as an option in a number of loudspeaker management systems (active crossovers with lots of features) to align bandpasses of loudspeakers, or at least to align the regions of interaction where bandpasses overlap. As such, the all-pass has a tangential effect on frequency response in the form of corrective changes which remove things like comb filtering between misbehaving bandpasses. Not very many people consider the all-pass filter to be a form of EQ, but it is used in the classic sense of equalizing the sound to be more neutral and flat. The BBE Sonic Maximizer is an all-pass filter sold to new sound system owners as a (largely useless) panacea. My friend Charlie Hughes wrote a paper about the proper use of all-pass filters in sound reinforcement: "Demystifying An Overlooked Tool: Using All-Pass Filters To Improve Directivity & Magnitude Response". Cheers - Binksternet (talk) 17:36, 24 April 2011 (UTC)


 * Ok, I had absolutely not thought of crossover networks or bi-amplification when I said that. Yes absolutely the RELATIVE phase of the signals sent to two speakers (at frequencies where both have similar outputs) is of crucial importance in the resulting sound (and radiation pattern, as your friend's article points out). I stick by my original point, that you can't hear phase shifts (and you may administer that ABX test on anyone who "can";-) but surely when you are separating a signal and then recombining it (acoustically) this can make a huge difference. Also true of 2 stereo speakers though you try to achieve symmetry in that case so the one and only (and serious!) mistake is hooking up one speaker backwards.


 * Of course we have to now figure out if "equalization" applies not only to equalizing an unequal frequency response (the literal meaning), and affecting the frequency content of the program to one's liking (the extended meaning) but also the filters used in an active or passive crossover network. That certainly involves high and low pass filtering, but I cannot think of the word "equalization" applying to crossover networks EXCEPT insofar as they CAN affect the equalization (net frequency response) of a system, in which case the phase response of the crossover filters contributes to that. (In fact I was already feeling a bit uncomfortable about including rumble and hiss filters under "equalization" since the point is just to get rid of those frequencies rather than adjusting them for either accuracy or taste, but I left it in since I don't know where else those would get discussed in WP). So this is a grey area. I WAS going to mention speaker equalization including with speakers like the Bose 901's (I once had a pair but had to leave them) which RELY on an equalizer instead of trying to make them flat. But that's a different issue (and one again where the phase isn't important).


 * So: is a speaker crossover an example of "equalization" or just an "audio filter?" But you mentioned a couple other things without explanation that sound more dubious. (Send me a link to the "BBE Sonic Maximizer" and I'll give you my honest opinion -- but it might not be pretty!). There is also a use for allpass filtering (sometimes adaptive) in reducing the peak to rms ratio of audio signals before hitting stages where they can clip (like transmitters). But this isn't relevant to hi-fi or normal audio systems. Mainly I thought this article was about USER CONTROLS of frequency response and speaker crossovers aren't usually adjusted by the user. By the way, there is now a Talk:Equalization (audio) page where this discussion probably belongs. -- Interferometrist (talk) 19:07, 24 April 2011 (UTC)


 * We should follow the usage of equalisation in the sources. If no source can be found counting crossovers as equalisers then we should not include them.  Sp in ni  ng  Spark  19:11, 24 April 2011 (UTC)

I agree with (I think it was Interferometrist's) suggestion that the Equalization (audio) article would be better named Equalization (music). The contents of Zobel network come under audio but don't really fit with where that article is going. There is a split in the meaning and use of equalisation between "music" on the one hand and "telecommunications" on the other.  Sp in ni ng  Spark  19:11, 24 April 2011 (UTC)


 * Agreed, though I didn't say (or didn't literally mean) Equalization (music) but something like Equalization (hi-fi and professional sound equipment) which obviously needs to be shortened. But again (and I think we agree) this one which is evolving will cover at least all "discretionary" uses of linear filters to improve the sound quality (either accuracy or according to taste) as opposed to non-adjustable filters permanently hidden inside systems like telephone networks which also restore the frequency response (and sometimes phase response) in a more objective way. But there's some overlap such as the RIAA and pre/de-emphasis filters in FM broadcasting and tape recording so I don't know exactly where to draw the line. If we wind up with a bit of overlap it wouldn't be the first time on WP, after all! But we seem to be agreeing that there are two sorts of meanings for "equalization" even when refering to audio filters, and one of them has to do with more than audio even though the article doesn't go there (yet). -Interferometrist (talk) 19:39, 24 April 2011 (UTC)


 * I think we need to push things in the direction of such a split. Part of the difficulty with editors like Atlantictire (and I don't want to seem to be picking on him, a large section of our readership probably has the same needs) is that they only want to hear about the music application.  Anything else in the article is just clutter to them.  I think we are talking about artistic uses of equalizers here but titles like equalizer (artistic) or equalizer (aesthetic) are not immediately obvious what the reader should expect.  All in all, I think equalizer (music) is the best compromise if we also make clear at the head of the article what the scope is.  After all, that is the very purpose of the hatnote template.  Sp in ni  ng  Spark  20:56, 24 April 2011 (UTC)


 * Alright, we don't have to decide this minute. And I do NOT think equalization of music is just aesthetic. Many sound engineers especially if they are involved in recording acoustic performances or running a PA of an acoustic concert would be quite offended to hear that. But the term has now INCLUDED the aesthetic aspect especially given that a lot of music that is "recorded" NEVER EXISTED in acoustic form. And I've been arguing on the other talk page to point out that the purely aesthetic aspect is a bastardization of the original term, but in common use. Anyway we need more input on both the naming and content of the two (now divorced) pages, both of which can use further work. Interferometrist (talk) 22:10, 24 April 2011 (UTC)
 * No intention at all there to offend sound engineers. I am well aware of what is involved in their work.  In any case I was not proposing that title, I only nominated as a possibility insofar as it enabled me to dismiss it from consideration.  Sp in ni  ng  Spark  23:41, 24 April 2011 (UTC)
 * In favor of Equalization (audio). Equalization may be used to record/create and modify non-musical sounds. Say, a movie soundtrack or tv character's voice. It is also used to correct feedback in public address systems. Spinningspark, I'm pretty sure readers will be able to deduce that if info on Zobel networks isn't covered in Equalization (audio) it's covered in Equalization. Equalization (aesthetic) and Equalization (artistic) sound pretty odd. Also, not sure fidelity or compensating for room acoustics qualifies as either, so I don't think they'd be helpful categories. But we're starting to loose the plot...--Atlantictire (talk) 23:32, 25 April 2011 (UTC)
 * Also, if we're talking about what audio engineers design and do then why not call it Equalization (audio)? I don't expect I'll ever hear anyone describe him/herself as an "aesthetic engineer" or "artistic engineer"!--Atlantictire (talk) 02:58, 26 April 2011 (UTC)

Moved-audio specific topics to Equalization (audio)
Material was duplicated here and in Equalization (audio). I moved and merged stuff that was clearly audio production and reproduction related to Equalization (audio). A also retargeted a couple of the proposed merges (Parametric equalization and Smiley face curve) to Equalization (audio). What's left here is general discussion and equalization topics related to communications. --Kvng (talk) 20:47, 25 April 2011 (UTC)


 * Ok, but summary style means you should leave behind a summary of the material that was moved and a main hatnote linking to it. If you really are going to delete all of the audio material in this article then it is a nonsense to have an audio mixing desk as the lede picture.  Sp in ni  ng  Spark  21:32, 25 April 2011 (UTC)


 * ✅ also there is summary text in the lead. None of this is perfect but I hope it gives us a better platform from which to make improvements. --Kvng (talk) 21:55, 25 April 2011 (UTC)

Equalization organization
Current organization of this topic appears to be as follows.
 * Equalization topmost article Appears to be written as WP:SUMMARY. Needs improvement.
 * Equalizer (communications) one of two child articles for Equalization. Appears to be written as WP:DISAMBIG but is not tagged as such. Needs to decide whether it is an article, summary or disambiguation.
 * Equalization (audio) the other child article of Equalization. Written as regular article. Past and proposed merges make this a comprehensive article.

I propose a simplified organization that incrementally improves upon the current organization. I don't claim this is an optimum organization, just that it is an improvement. I assume my fellow editors appreciate the value of incremental improvement. -—Kvng 16:06, 17 January 2013 (UTC)
 * Move any Equalization information not already present in linked articles into those articles. There are only 3 refs in Equalization so I don't expect this to be a lot of work.
 * Convert Equalization into WP:DISAMBIG by merging Equalizer (communications) into it.
 * No changes to Equalization (audio)


 * I've done work to tease apart audio (Equalization (audio)) and telecommunications (Equalizer (communications)) equalization topics. Hopefully this is an improvement. Additional improvements or comments are welcomed. ~Kvng (talk) 20:47, 15 July 2015 (UTC)


 * I've moved the dab page to Equalization in place of the redirect that was there so the dab has the prime title. I have renamed Equalizer (communications) to Equalization (communications) for consistency and to better match the material that is now on that page.  I feel that Equalization (audio) is now slightly misnamed following the reorganisation.  Much of telecomms equalization is to do with audio but that material is now on a different page.  Something like Equalization (music) might be more appropriate. SpinningSpark 00:36, 17 July 2015 (UTC)


 * Having looked at the very long list of incoming links to the dab page, I am now not so sure that this split was such a good idea. In many cases it is going to be impossible to decide which article to link since the context of the source page could refer to either or both.  An alternative to remerging would be to create an overview article at Equalization and move the disambiguation page back to Equalization (disambiguation).  What do you think? I have archived a copy of "pages that link here"  to maintain visibility of the original list of links.  People are bound to try and "fix" these and inevitably get some wrong.  This would best be done after we have a stable structure. SpinningSpark 11:49, 17 July 2015 (UTC)
 * I will implement this in a few days time if there are no objections. SpinningSpark 16:43, 19 July 2015 (UTC)


 * This area of coverage is a mess but I feel like we're on the right track. I've started disambiguating articles linked to Equalization and have not found anything I can't deal with. I've found more ambiguosity at Equalization filter and Equalizer. I believe that going through and clearing up these cases will improve the articles involved and make things less messy. Please point out any specific examples where you find disambiguation difficult and we can discuss further. ~Kvng (talk) 14:26, 23 July 2015 (UTC)


 * I completed disambiguation. The only place where I couldn't resolve an audio/communications ambiguity was in Equivalent impedance transforms. ~Kvng (talk) 18:52, 23 July 2015 (UTC)
 * I'm not quite clear whether you are agreeing, or disagreeing, with my proposed changes. SpinningSpark</b> 10:45, 7 August 2015 (UTC)
 * I found only one case (Equivalent impedance transforms) where discussion was general enough that the equalization application (audio vs. communication) was not given in the context. If we created an overview article for equalization, I'm not sure what would link to it aside from Equivalent impedance transforms. ~Kvng (talk) 14:08, 10 August 2015 (UTC)