newman (11/04/82)
The thing that kills me about the coming digital audio era is this absurd obsession with 90 db dynamic range! Yes, live orchestras etc. do attain 90 or even 100 db dynamic ranges, but you are going to claim that you want that in your living room? There was a good point made recently that you are condemned to listen over your refrigerator, traffic noise, talking, and so on - rarely less than 40 - 50 db background noise. In order to hear the quietest sections at all on a 90 db dynamic range recording, the peaks will either cause amp clipping that will guaranteed fry your tweeters, or cause hearing damage eventually, or at the very least alienate anyone remotely near you. The 50 - 60 db range provided by the very best current digital/dbx/direct-disk records seems to me ideal. It seems clear that exactly recreating some original performances is idiotic. What I think is more important than recreating the original dynamic range is recreating most (all?) of the spatial qualities of the original.
burris (11/05/82)
#R:utcsrgv:-65700:ihlpb:4000019: 0:1214 ihlpb!burris Nov 5 12:55:00 1982 Yes, I will claim that I want the 90db. of dynamic range in my living room! To start with, the noise level in MY living room is well below 50db. Secondly, having 90db. of dynamic range does not mean that it's all being used for music. Thirdly, the sound of a recording environment is determined by its reverberant field, including ALL reveberations which remain within the threshold of hearing. If the level of any musical source is 90db (not uncommon) and the threshold of hearing is 0db. (a little more uncommon) then 90db. of dynamic range MUST be maintained in order to faithfully reproduce the recording environment even if the music actually only uses 40db. of dynamics i.e. 50db. - 90db. In addition, 90db. is accepted by OSHA as the maximum level of audio of ANY frequency that has NO maximum exposure time for zero hearing loss. Granted, it begins to fall off quickly above this level but then who wants to be visited by the police. The sound level of 90db. also happens to be the point on the equal loudness contours where humans begin to hear equal intensities throughout the frequency range as being equal. Resisting the temptation to flame-on.(again!!!) Dave Burris ihlpb!burris BTL - Naperville
newman (11/09/82)
Whew! It is getting rather tiring to get nothing but flames on this group
(often accompanied by heated air). Please let's revert to calm, intelligent
rational discussion of topical issues in audio. If you happen to be an audio
guru, fine, but don't abuse others for taking a differing point of view (there
is room for personal opinion in areas of this field).
- regarding dynamic range, I got several replies stating a benefit of 90 db
range on true digital records was no audible noise - it seems likely that the
major source of noise on a good analog record is the surface noise caused by
the physical groove contact, absent of course with dad's. There is also the tape
hiss etc. of any intermediate tape stages. But that seems to have little to do
with the dynamic range of the recorded music, which was what I was talking
about. One person in particular seemed to translate a music dynamic range
argument into an argument about the spectral characteristics of noise (why?).
I believe musical dynamics is a wideband phenomenon, at least when you take
into account a wide variety of music. I know dad's will have essentially no
background noise, but it still seems to me that to reproduce the full musical
dynamic range of say an orchestra in the average home so that all of it is
easily audible will make the peaks at a very high level (hence Phase Linear's
claim that you need > 1000 watts on peaks to avoid clipping at "realistic"
levels. Check out the Carver M1.5).
- oh yes, the recent claim that the dynamic range of an audiophile record
"lasts for only the first few plays anyway" is incorrect with the right
playback equipment.
I welcome calm intelligent informed discussion on this and am quite willing to
do an about face if convincing facts are presented. Flamers need not reply.
<flame still off>
Ken Newmanbhaskar (11/12/82)
hmmm! this is a little tangential, but the fourier spectrum isn't everything. a fundamental assumption with frequency domain techniques is that the system is linear. the human ear isn't, and if you disagree, just listen to a 15 kilohertz sine wave and a 15 kilohertz square wave. they will sound different because the human ear is essentially a non-linear system. of course, to a good approximation, if you have a large bandwidth system, you can gloss over this... again, the brain has quite a good signal processing system built in, and may be able to extract signals even with excessive noise, but then, i'd like to listen to the music, and not to the system.
wildman (11/12/82)
Hmmmm indeed. fluke.341 seems to think that a Fourier transform (Discrete, as was referred to by jj) is NOT reversable. The comments about non-linear systems really don't matter, since there are a large number of papers that have studied the response of the ear to signals in the Fourier domain, frequency. I believe that is what jj refers to. As I understand, he does not propose to put the signal through the ear's transfer function in the Fourier domain, and then try to recover the information, which would NOT work. L. Greystoke
rjr (05/11/83)
Relay-Version:version B 3/9/83; site harpo.UUCP
Message-ID:<485@we13.UUCP>
Date:Wed, 11-May-83 15:44:51 EDT
I agree with the comments that audio with a large dynamic range has no
place in a car. There are also times at home where one does not like
a wide dynamic range, such as background music when eating, playing
cards, etc...
I am a holdout in that I still prefer reel to reel for taping and the
only reason I have any cassette gear is to prepare tapes for the car.
When I make any cassette tapes, and occasionally reel to reel too,
I use a home made compression amplifier. This unit is strictly an
AGC system that treats the entire audio spectrum equally. Playing
tapes made this way does save a lot of reaching for the volume control
on the dash.
Most all broadcast stations use compression and all are required to
use peak limiters to prevent going over 100% modulation. My experience
is that only the better classical music FM stations have any dynamic
range to speak of.
What really irritates me is in my car stereo unit, the radio output
is so much greater than the tape output that when the tape ends
it just about tears the speaker cones.
Bob Roehrig
...we13!rjrcaf@cdi.UUCP (05/18/83)
With the software so expensive, the last thing I need is an irrestible inducement for thieves to break into my car again.. Thank you, I'll dub my CD's onto cheapo C-90's with a compressor and play them on a $150 player, not a $1000 hierloom. -- Chuck Forsberg, Chief Engr, Computer Development Inc. 6700 S. W. 105th, Beaverton OR 97005 (503) 646-1599 cdi!caf
ms@dvamc.UUCP (08/08/83)
With all the talk of the incredible dynamic range of CD vs analog discs, what is the average dynamic range of loudspeakers??