User talk:Donvr

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Contents 1 High fidelity vs. small rooms

[edit] High fidelity vs. small rooms

It's possible to get good, solid low frequencies in small rooms. I will continue to delete your paragraph about small rooms and long wavelengths unless you work to define low frequencies as cancelling each other out by reflections in a small room that isn't amply absorptive at low freqs. It is absolutely false that long wavelengths need long spaces to 'develop'. Consider the tiny listening space within headphones. Binksternet (talk) 05:14, 11 January 2008 (UTC)

OK, I wondered about this paragraph disappearing (after a Wiki system problem though). I won't push this matter any further, because I threw away all HiFi-documentation pertaining to this many years ago. And one booklet still left in my possesion, the Philips guide on loudspeaker enclosure design only mentions its effect relative to the design for labyrinths or horns. (Possessing cut-off, as opposed to the theoretical infinite flat panel or "baffle"). The argument can also be made along the parallel with standing waves in organ pipes being present or not depending on its length. And a room can be considered as only one type of pipe enclosure. I have not made this up, but its relevance is not so high. Whenever I find something back I'll return. Regards, Donvr (talk) 13:42, 19 January 2008 (UTC)

Back to the subject after a discussion yesterday evening with an expert (AES contributor). Standing waves being built up contribute to the diffused wavefield that's needed everywhere for a faithfull reproduction. Direct sound constitutes only a very small part of the listening experience. That's why any performance in the open air missing sound reflections is much less gratifying to the ears.

Now to my argument: concert halls are of such large dimensions and exhibit such large delay times (echo/reverb) that very low frequencies are able to be present in the diffused wavefield. Contrary to smaller rooms like in homes, where the smaller dimensions prevent standing waves for very low frequencies. You only hear the direct sound of those. So my phrasing should have been: very low frequencies, where the room dimensions are below the standing wave for them (340 m/s divided by the frequency equals the wavelength), can not be just as faithfully reproduced as in larger concert halls. The lack of standing waves for those prevent a proper diffused wavefield for the lowest frequencies. This will not prevent direct sound reaching the ears, but listening experience is more limited. My error was in stating that those frequencies are non-existent, they're weakened... But good solid low sound reproduction remains your statement, not shared by me and my colleague.

A Dutch HiFi magazine HVT, contains a series of tutorials on audio reproduction from 2007 to today. In those articles, two statements were made and argumented by the Dutch TNO laboratory on sound recording and reproduction: 1) in principle any sound reproduction of a diffused wavefield in a concert hall can only be mathematically correct, when an artificial head dimensioned to the listeners head is used and reproduction takes place over a equally dimensioned headset (exact point to point reproduction of a mixture of both direct and indirect sounds from the original wave field) 2) if the second choice, reproduction of the sound wave itself is tried for, the speakers as point sources where only direct sounds originate from, should be helped by lots of indirect sound reflected from the walls of the listening room. This strongly influences both position and direction of the speakers with respect to reflecting surfaces like walls (point to multipoint reproduction) These articles as such do not adress specific issues for very low frequencies like I did, but endorse the principle of a diffused wave field as being conditional for faithfull reproduction. Other parts of these articles pertain to time differences between direct and indirect sounds in the listening room and its effects. These parts go beyond our argument and are not reproduced here Donvr (talk) 17:08, 27 February 2008 (UTC)