Talk:Directional sound

There seems to be some disagreement about whether there is something special about "electrostatic" speakers, that create some sort of higher directivity than other loudspeakers of the same dimensions. I'm not sure why someone keeps adding this information, but it's erroneous. Huygen's_principle states that every wavefront (or source) is equivalently described by the aggregate of a set of infinitesimally small point sources distributed equally to the original source. It doesn't matter if these point sources come from a bunch of loudspeakers, the motion of a membrane, or even a plane wave going through an aperture; it's still the exact same distribution of point sources that makes up the complete source. I would urge anyone who doesn't agree with this to please provide some solid references that contradicts some 300 years of well established wave physics.--Rand144 (talk) 23:54, 9 March 2009 (UTC)

Directional audio is becoming hugely important for a variety of applications. One of the most significant areas is in digital signage. Currently there are 3 ways in which directional audio is achieved in these applications: Ultrasound (which has been discussed), speaker arrays (which has been discussed), and flat diaphragm electrostatic speakers (which has been added but a user keeps deleting). It is reasonable to believe that someone searching Wikipedia for directional audio, may indeed be interest in how directional audio is being achieved today (technologically speaking). Flat diaphragm electrostatic speaker are not the same as speaker arrays. No one in stating that speaker array cannot create directional audio, only that flat diaphragm electrostatic speaker are another major way this is being achieved now.--Jacktutucin (talk) 08:55, 10 March 2009 (UTC)

The point is that electrostatic speakers are just one form of traditional audio source, and there is no difference between the directionality of an electrostatic loudspeaker and any other audio source of the same size (such as an array). Even a huge moving coil speaker would be exactly the same. The article as modified claims that there is something special about the electrostats, which just is not the case. The mechanism of vibrating a surface (whether through a moving coil or electric field) has no impact whatsoever on the directivity of the source, and no citations have been provided that indicate otherwise. That's why it's irrelevant to the article. Also, I would note that this article is not intended as a piece of marketing literature, which is what it's unfortunately becoming. --Rand144 (talk) 17:12, 10 March 2009 (UTC)

I'll also add that, by the definition you provide, there are hundreds of ways of making so-called "directional sound", conveniently listed in the loudspeaker article. Horns, piezos, electrostats, ribbon, planar magnetic, bending wave, flat panels, Heil air motion, plasma arc, etc. As long as they're the same size, very last one of them creates sound with equal directivity as an electrostat, and has all the same properties, such as the uniformity of the nearfield and the other properties implied to be unique to electrostatics by your edits. There's nothing difficult about directional sound with speakers - you just need a big speaker.--Rand144 (talk) 20:41, 10 March 2009 (UTC)

Someone who perhaps has a vested interest in electrostatic speakers is starting an edit war, and is no longer participating in the discussion. The additional information about electrostats does not belong here for the reasons above. In fact, the statements such as "While the sound levels produced by traditional speakers will drop by 6 dB for each doubling of the distance away from the driver, the resulting drop from a planar wave source is much less" is misleading and technically incorrect. Any kind of speaker of the same dimensions is also a planar wave source - whether it is electrostatic or "traditional" doesn't affect the sound field properties at all. I don't know why this is so controversial.--Rand144 (talk) 13:18, 13 March 2009 (UTC)

Someone who perhaps does not understand the significance of flat diaphragm electrostatic directional audio speakers and their value in the current audio ecosystem continues to remove relevant content. I also do not see why this is so controversial as any meaningful discussion of directional sound must include the significant and relevant technologies that are used to create directional sound today... Perhaps someone has a vested interest in other technologies used to produce directional audio is continuing to remove this information.--Jacktutucin (talk) 21:56, 13 March 2009 (UTC)

The problem is, the claims made about electrostatic speakers apply equally to all kinds of loudspeakers. You have not been able to provide a shred of evidence that it is anything except physical size that makes a loudspeaker directional - it's a simple consequence of Huygen's Principle well supported by mathematics and experiments. Let's keep this article accurate and objective, and refrain from polluting it with marketing language. I invite you to please present some evidence that there is a fundamental difference of directivity between a surface set into vibration due to an electric field, vs. one made by a magnetic field. Until you can provide this evidence, please do not continue to add incorrect information.--Rand144 (talk) 20:53, 14 March 2009 (UTC)

An anonymous user is unfortunately starting an edit war by adding incorrect and unsupported technical information, as well as marketing language intended to promote a particular type of loudspeaker (a clear NPOV violation). I am happy to discuss the technical aspects of the information here, but unfortunately I don't think he or she has any interest in having an objective discussion.--Rand144 (talk) 14:43, 16 March 2009 (UTC)

I do not understand what the 'marketing language' the user is speaking of. If the user was to read the reference articles he or she may gain a better understanding of the material. The page is listing several other methods of producing directional audio: ultrasound, speaker arrays, sound domes. Nobody, I believe, is questioning the justification for them being listed here, yet including electrostatic speakers capable of producing directional sound seems to be difficult for 1 user to accept despite the fact that if he or she were to attend pro AV trade fair they would see how present this technology is. The fact that this single user does not understand the technology, or has not read the evidence supporting it (read cited literature), does not make it inaccurate. I would invite anyone as unfamiliar with this type of technology as this 1 user seems to be to investigate the current research in this area and to look at the products produced by companies such as Quad and MartinLogan. I would also be happy to recommend a local trade fair where someone who doesn't understand this technology (as this 1 user doesn't) could get themselves up to speed with the latest technological advancements..--Jacktutucin (talk) 22:15, 16 March 2009 (UTC)

I have no problem with including a mention of electrostatic loudspeakers, as just like all loudspeakers, can be directional if they are very large. But the claims that there is something unique about directivity in electrostats is flatly incorrect, and you have not yet offered a verification. I know about electrostats - the main article has plenty of information that does not need to be duplicated here. Your edits violate both NPOV as well as the Verifiability requirements for articles. Trade fairs do not count as references.--Rand144 (talk) 11:21, 17 March 2009 (UTC)

Perhaps the issue is coming the use of the term 'large'. What do you mean by saying that the directional electrostatic speakers are only directional because they are large? --Jacktutucin (talk) 08:16, 19 March 2009 (UTC)

As I've referenced, Beranek, Huygen, and many others clearly show that the directivity of a source depends only on its physical size, and not the method of transduction. Why would a sound wave care if it came from a panel moved by an electrostatic vs. magnetic force? The air doesn't know the difference.

The maximum directivity of all sources depends on their physical size vs. wavelengths generated, and nothing more. That's what Beranek says in his textbook. Electrostatics are usually larger than common bookshelf speakers, because the limited membrane motion limits output levels, so a greater area is needed to compensate. Because they happen to be larger, they happen to be more directional - but only when compared to a small loudspeaker. Compared to any speaker (or speaker array) of the same size, the sound fields are *equal*. Beranek proved this, as well as the other features your edits imply to be unique to electrostatic speakers (drop with distance, etc.) That's why the edits are incorrect.

If I built a 2" diameter electrostatic speaker, it's directivity would be exactly the same as a 2" magnetic speaker. The same goes for a 2 foot speaker, or a 20 foot speaker. Size is all that counts.

I was inviting you to cite a source that contradicted Beranek and Huygen, but I really don't think one exists. --Rand144 (talk) 20:02, 19 March 2009 (UTC)

The reference added makes general statements about (large) electrostatic loudspeakers that is true for large panels, but these statements are also true for all other types of loudspeakers of the same size, exactly for the reasons above. That's the point I've been making all along: all loudspeakers have the exact same directivity and loss/distance features as electrostatics, as long as they are the same physical size. This is unequivocally proven by Beranek in his textbook. That's why the edits are incorrect, and are very misleading. I also note the removal of other information that is absolutely true and supported by Beranek. Please refrain from those edits.

In checking the reference added, I noted that not only is the cited name wrong (it's Borwick), but interestingly, when calculating directivity of the source for analysis, his calculations (p.157) are based on none other than Beranek's book, and he referenced the very chapter that I referenced in this article! He even uses the same equation for the directivity index, which, as I've stated all along, depends *only* on source size versus wavelength (pi*D/wavelength). The very same equation applies to all sources, including electrostats, magnetic speakers, etc., per Beranek, the original source.

The very reference cited to refute the original article served to strengthen it. --Rand144 (talk) 13:59, 25 March 2009 (UTC)

Just came in to say, as an outside person who just wanted to learn about directional sound, the reference to electrostatic speakers definitely seems a distraction and misleading as I came away thinking they are somehow special for directional sound. It wasn't until I read this talk page that I realized it was a red herring. I would suggest you remove it from the main page because I feel it is confusing at best to even bring it up. Just mention larger speakers. No need to discuss the underlying mechanisms because it is clear that you can have many different types of large speakers. — Preceding unsigned comment added by 2620:0:691:B309:2098:D311:BF96:DE69 (talk) 17:12, 17 February 2017 (UTC)