Talk:High fidelity

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[edit] Sources?

A lot of the information contained in this article maybe be common knowledge to audiophiles, but as someone who is trying to learn about accurate sound reproduction, one of the first things I noticed is that a lot of conclusions in the explanation and history of hi-fi cite no references. Since this general topic tends to be very subjective, I think it's especially important to note where everyone got their sources. As of right now, there are entire sections without any references, and in parts, it borders on opinion or speculation. --Rayt5 19:20, 6 June 2007 (UTC)

[edit] Double-blind live-versus-recorded tests?

First, does anyone have any information on double-blind live-versus-recorded tests to determine whether or not reproduced sound has reached a degree of perfection so as to be indistinguishable from live sound? Acoustic Research conducted and publicized a number of "live-versus-recorded" demonstrations in the 1960s, but they were, of course, marketing exercises designed to show how good their speaker systems were.

Second, I don't have references so won't add this to the article now but an interesting point is that at virtually every stage of progress, starting with Edison cylinders, you can find contemporary quotations in which people say in so many words that there are no audible differences between the original and the recording. Dpbsmith (talk) 20:52, 21 May 2005 (UTC)

Using a graphic equalizer, but mainly only medium-priced equipment, I organized an extensive live-vs-recorded test, single-blind, which I reported in the Boston Audio Soc. Speaker, March 1975. We found that the listeners could be fooled if they were about 20 feet away from the violin and trumpet, but not if they were closer. (Probably the reflected sounds are not frequency-equalizable when closer, and loss of phase coherence might also be involved.) Similar things have been done by others, but not reported in detail. (See for example, Ken Pohlmann's note in Stereo Review, August 1998, page 12.) Similar things have been proposed, but not actually done. (See for example, D. Y. Klepper, J. Audio Engineering Soc., Vol. 52, No. 10, page 1060. 24.225.147.254 14:17, 11 January 2006 (UTC)Dan Shanefield. Jan. 11, 200624.225.147.254 14:17, 11 January 2006 (UTC)

I added the words "single-blind testing of loudspeakers" to the part about what Floyd did in Canada, and I also added "of amplifiers" to the part about what I did. (It's an important historical distinction, and there was lots of controversy about it in the "golden ears" magazines, around 1975 to 1985, which has pretty much cooled down now [except for groups.google.com / usenet disputes, which never seem to resolve themselves.] ) ````Dan Shanefield, Jan. 10, 2006.````

[edit] Should there be info about VHS hi-fi?

hi-fi on a VHS recorder means that the audio is not recorded on the audio track but is buried under the video.

[edit] "music below 5 Hz is probably non-existent"

Back in the early 1970s I knew a serious audiophile who had an amazing setup. It started with a specially built room, of course, a narrowish one that extended the entire length of his house along its longest axis. It had a couple of Tannoy 16" woofers. And amplifiers that could drive them with authority.

He had one recording that was a live recording of some kind of musical event in which there were dancers dancing on a stage. When the dancers hit the stage, there was a thud and you could feel something hit your chest. It was not just impressive, it was amazingly _realistic_. An utterly convincing illusion being in the presence of solid human mass. I think there was material well below 20 Hz, and in this particular recording I think it really added something nontrivial to the sonic experience.

That was my introduction to what really low bass sounds like when reproduced.

Of course, 98% of his recordings didn't have any true low-bass program material. He had a few special ones that he trotted out to demonstrate with. A low organ note, of course--I don't remember what piece of music it was in, which tells you something--that you couldn't really hear. I mean I'm not quite sure what it was good for, or why the composer put it there, there wasn't any real sensation of pitch, just a sort of wobbly feeling on your chest and eardrums that made you want to clear your Eustachian tubes.

(I'm almost convinced that the only time you hear those really low organ notes in a recording is when your speakers are distorting...)

Maybe only 2% of his recording had real low bass in them—but maybe a third of them had very low-bass _rumble_. There was a sort of once-per-revolution "great sucking sound." On a slightly warped record you could watch the tonearm tracking the warp (perfectly, of course--it was that kind of system) while you could feel your eardrums sorta get pulled every time it hit the warp.

Me, I'm happy enough with bookshelf speakers that roll off at maybe 50 Hz.... Dpbsmith (talk) 23:46, 3 October 2005 (UTC)


yeah but bro, human thumping noises aren't music in the sense of notes. I think that that's what "there is probably no music lower than 5hz" is getting at. It could be edited for clarity, but factually it's fine. Philmcl 14:40, 4 August 2006 (UTC)

[edit] Iso definition

Hi-Fi is defined in a iso standard (or something like iso) with very clear distinctions "what is hi-fi, what is not". Maybe this should be researched by someone and added to the page? Peter S. 11:07, 7 October 2005 (UTC)

Yes why dont you research it?--Light current 00:19, 17 May 2006 (UTC)
DIN 45500, there you go, somebody added it. No need for me to research :-) Peter S. 14:54, 14 June 2006 (UTC)

Hi:The definition is .5 distortion over the *entire* harmonic range. A

[edit] Grammar

I corrected the grammar in the first sentence, but it was reverted. I do not believe it is acceptable to day 'High fidelity means' any more than it is acceptable to day 'red means', because it is an adjectival phrase and cannot be a subject. You can say. Also it is dubious to say 'dog means' because though a noun, dog is not really the subject, it is the word dog. You can say, 'a dog is...'. So you can say, 'the phrase hi-fi refers to a level of quality', or 'high fidelity reproduction is a standard of reproduction that...' but not 'high fidelity means'. Lindosland 13:50, 28 October 2005 (UTC)

Sorry, I seem to have been mistaken in thinking it was reverted - for some reason the history didn't seem to update properly, (site down warning came up a bit later) but is ok now. Anyway, the reasoning above explains what I did. Lindosland 15:26, 28 October 2005 (UTC)

A simple solution to this sort of thing is to say: The term 'floobydust' means.....--Light current 01:04, 17 May 2006 (UTC)

[edit] Comments on LF response discussion

Incidentally, I built a listening room recently, specifically to find out what exactly matters. It's 25ft by 18ft with two 18inch woofers mounted in one wall in optimal positions, crossed over to a pair of Mackie HR824 monitors at 110Hz. The woofers are effectively in an infinite baffle (with a garage behind as enclosure) and have been equalised down to 12Hz using close up measurements. Room modes spoil what would be an ideal 12Hz to 20kHz response, and I am working on ways of eliminating these as part of a Lindos Electronics project, but the sound is very good. my conclusions are that an extended low end provides a feeling of presence, largely from the true thump of bass drums etc, and that this is partly the result of maintaining phase response, so that a unidirectional pressure wave is notconverted into an oscillation, as is the case with most speakers. However, I would say (from trials with filters) that while a response flat to 30Hz makes a big difference, and a response flat to 20Hz, is slightly better, extension below 20Hz makes no difference.

I would emphasise though, that room modes are the main problem, and it is only because most speakers roll off at LF that we tolerate them. A flat speaker immediately brings problems of a bass-heavy sound, because of the peaks in room response, which are less tolerable than the dips.

The question is not whether 'music exists' below 30Hz, say, or even whether we can hear tones at these frequencies. It's whether we perceive a difference on sounds, and the sounds that have very low content are drums, rumbles of thunder, even air conditioning, and occasional thumps of people moving, which give a feeling of reality. Some experiments have revealed that lateral low freqencies at presence, ie stereo bass. I would never use a single woofer because it couples into room modes too much wherever you put it. The lowest note on a bass guitar is about 30Hz I'm told, and bass guitar notes tends to be the problem when bass is extended because they sustain long enough to build up high levels of resonance in the room modes. Muddy bass has little to do with speakers in my experience, and everything to do with rooms once the bass is not rolled off.

The reason for using 18 inch units was of course so that they do not distort - cone movement is small even at a loud 20Hz. This is essential because our ears are far more sensitive to the harmonics of 20Hz than the tone itself (see equal-loudness contours.

I make recordings of my sons band using very flat omni mics, and would point out that the chief obstacle to Hi-Fi on todays recordings is lack of headroom. You can't use compression and then talk of Hi-Fi, yet extreme compression is used almost universally on commercial recordings! This removes both bass and the sparkle of cymbals (which have true peaks to 130 to 140dB SPL at 2m)

See our 'Test Sheet Database' for tests on our speakers and room and many other things, at www.lindos.co.uk.

Hi Fi was defined in a DIN (German) standard in the sixties which was often referred to then in Hi Fi magazines, but it fell out of use. Lindosland 13:50, 28 October 2005 (UTC)

[edit] Grammar

I've put back those two words, because I believe they are necessary for good grammar. To say 'high fidelity can be applied to systems' has the meaning that fidelity can be applied like a coat of paint to a system! It is the term 'high fidelity' that is applied. Lindosland 15:41, 28 October 2005 (UTC)

[edit] grammar/clarity

The 2nd paragraph, the one just before the contents (High-fidelity enthusiasts are often known as audiophiles. The strive for high fidelity audio reproduction, when taken to its extreme, is often termed "high end".) confuses me. Following the first sentence, "They strive for high fidelity..." would seem to work, but then the last half of the sentence makes that nonsense. "The pursuit of high fidelity..." is little better, and still doesn't make a lot of sense. So, I've changed it to read: "High-fidelity enthusiasts are often known as audiophiles. The equipment they prefer is often termed "high end." Scmdn 20:24, 28 February 2006 (UTC)


[edit] Vinyl/Turntables

This article makes no mention of vinyl's presence (and resurgence) as a popular medium among contemporary audiophiles. I feel like this is an inaccurate representation. I lack the historical knowledge to do it justice, though. Could someone help on this? Philmcl 14:42, 4 August 2006 (UTC)

Vinyl Hooey. William Greene 19:30, 7 October 2006 (UTC)

[edit] External links

I have ejected the links below from the main article as being in violation of WP:EL. If these are refences to contents in the main article, they should be included as such, in a format acceptable to WP:FOOT. Otherwise, they should remain deleted.


[edit] Reality of Hi-fi systems

The words high fidelity are a bit of a misnomer - an expensive hi-fi system nowadays doesn't have a flat frequency response, it's geared more towards music enjoyment. Are there any sources that confirm or deny this? It's common knowledge among the sound production community that studio monitors are meant to give a flat response, not color the sound at all, and that good monitors sound terrible. -74.192.43.101 16:06, 12 October 2007 (UTC)

If it does not have a flat frequency response, then it is not high fidelity. You may want to take a look at The Audio Critic. Good loudspeakers—consumer or professional—should have a flat response and not colour the sound. William Greene 18:28, 22 October 2007 (UTC)
Yes, flat is good. There's more to it than flat, though. "Flat" doesn't doesn't speak to time-varying qualities nor to amplitude-varying qualities. "Flat" on a normal RTA is often revealed to be very much otherwise with FFT analysis. Binksternet 21:32, 22 October 2007 (UTC)

[edit] Double-blind tests

“Nevertheless, the double-blind methodology does not rule out a long-term test conducted at leisure in comfortable situations.” “Last sentence makes no sense, and no one suggested that it did. Contains weasel-words. Removed.” Why did that sentence make no sense? It makes sense to me. What are the weasel-words? Why are they weasel-words? William Greene 14:01, 29 October 2007 (UTC)

Agree. I have edited it accordingly. The section was full of vague, unsubstantiated weasel-worded opinion. Consider:-
  • The double-blind listening comparison is now a standard procedure with almost all audio professionals respected in their field. Well if its standard how come not all "audio professionals" use it. Anyway where are citations to support this?
  • marketing purposes, a few manufacturers of very expensive audio equipment dispute the need for this test. Really? Which manufacturers? Again where are citations?
  • proponents of double-blind testing have an agenda to discredit that such subtle differences exist Such allegations should not be included in an encylopedia article.
  • However, there is still another level of argument ... This is opinion and original research.
Also the subject of double-blind tesing is very small beans in the article's main subject, —Preceding unsigned comment added by 81.153.70.34 (talk) 01:50, 5 January 2008 (UTC)
Not all audio professionals use it, because some audio professionals are unethical--the black hats. In other words, for marketing purposes, some vendors will dispute the need for this test. Which vendors? How about taking a look at Stereophile? Do not be surprised if some of the vendors that place ads in that magazine dispute the need for double-blind tests. Here is an example of marketing purposes versus double-blind tests: The Ongoing Debate about Amplifier "Sound." The details are in The Audio Critic. What do you mean "very small beans"? William Greene (talk) 17:37, 25 January 2008 (UTC)

[edit] Dimension of listening space

I deleted the old saw about short room length preventing low frequencies from "developing". Low frequencies aren't defined as waves of comparatively long length, they are defined as rarefaction and compression cycles of comparatively slow duration. Such rarefaction/compression cycles can happen equally well in any size of listening space. How would it otherwise be possible to test hearing down to 20 Hz with headphones, the listening space of which is at most a couple of inches? Binksternet (talk) 15:54, 9 January 2008 (UTC)

Donvr, the reason people have a tough time getting low frequencies to behave nicely indoors isn't because the listening space doesn't have large enough dimensions, it's because the walls, ceilings and floor bounce LF wave energy around the room, creating cancellations. It's possible for a small listening room to be designed with a high degree of LF absorptive materials at the boundaries so that the room yields a rewarding high fidelity soundscape all the way down to the limits of hearing.
I will continue to correct any mention of a small room not being large enough for subwoofer freqs unless the absorptive aspect is written in and the cancelling out via reflection is offered as a possible explanation. Once again: explain how headphones might be able to work clearly down to 20Hz with only a few cubic centimeters of volume between the driver and the ear. Binksternet (talk) 05:08, 11 January 2008 (UTC)

It might be useful, for the purposes of the Discussion, to explain a theoretical misconception, too. There are many situations in sound and vibration where there's a tie between a physical object and the lowest frequency it produces or responds to. For example, an open instrument string does not produce any lower note when plucked. That same restriction does not apply, hopefully obviously, if the string is mechanically forced to resonate at a lower frequency. I.e., one could set a very strong electromagnet next to a metal string, and force it to move at any lower frequency. Once a second. Or even once a day. In this situation, the natural resonance of the string is irrelevant. In this same way, a speaker's low frequency sound does not depend on the size of the room -- it's being driven by a powerful, independent, energy source.

There's a little more to the "room size" argument, however. For a static area to reinforce a sound (to create a standing wave or a reinforcing wave), it must be of sufficient size. This is a factor that causes people to notice differences in large rooms. But. If a room reinforces a deficiency in the recording or the audio equipment, all well and good. If one is a listener who enjoys artificially boosting low frequencies for their "impact", that's fine, too. That person may well want a large room which intensifies low sounds. Unfortunately, this intensification isn't readily changable. So a room that emphasizes, say, 20 cycles per second, will always emphasize 20 cycles per second. Whether the recording caught the source's 20 cycle sound well or not. I.e., everything at 20 cycles per second will be emphasized. For a discerning audiophile, that's a negative factor. For listeners who are less critical, but loving the "shock" of low frequency sounds, it might be positive.

In practice, of course, no listener is purely one way or the other. And this creates a good deal of confusion, because very acute listeners (and articulate listeners!) won't appreciate exactly the same thing. I'll give myself as an example. I can hear low frequency noises that are inaudible to almost everyone else. Enhanced rock-and-roll low frequencies can cause extreme (bad) reactions for me. When everyone else at a concert is having a great time, I'm looking for the exits. For me, a large listening room which emphasizes low frequencies is a nightmare. For other people who, effectively, can't hear the low frequencies very well, the perceived boost is less consequential. So people of good faith can have quite different experiences. Hence the persistence of the large room mythologies.

Alpha Ralpha Boulevard (talk) 11:23, 25 April 2008 (UTC)

[edit] Cleanup!

The lead 'graph says that in the 50s and 60s HF was defined by a standard not defined until the 70s. Absurdities, and even apparent absurdities, require attention.
--Jerzy•t 02:52, 8 April 2008 (UTC)