Is there a problem with the IASA 2.4.1.2. Dynamic Range (signal to Noise)?
"The A/D converter will have a dynamic range of not less than 115dB UNweighted, ......."
??
Or is it just to the DAC side of things?
BTW-- anyone out there, besides me, use closed back headphones out in the rural areas? I cant seem to get a measure of my NC with headphones on. With a typical book value of 30dB SPL at the rural home and another 20-30dB isolation from that with headphones on. Hmmmm, maybe I could hear to 4dB level?! Its a very quiet listening environment which adds to the dynamic range of sounds I could hear.
THx-RNMarsh
"The A/D converter will have a dynamic range of not less than 115dB UNweighted, ......."
??
Or is it just to the DAC side of things?
BTW-- anyone out there, besides me, use closed back headphones out in the rural areas? I cant seem to get a measure of my NC with headphones on. With a typical book value of 30dB SPL at the rural home and another 20-30dB isolation from that with headphones on. Hmmmm, maybe I could hear to 4dB level?! Its a very quiet listening environment which adds to the dynamic range of sounds I could hear.
THx-RNMarsh
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ANOTHER straw man? What were the others? Don't bother to even try. You won't be able to substantiate that claim either.
Don't you even remember what you've written?
You stated that human hearing had a dynamic range of 120dB, and that because of this, the dynamic range of the recording needed to be approximately 120dB in order to keep the noise from being AUDIBLE.
You didn't say this in the context of absolute hearing thresholds under ideal conditions. You said it in the context of LISTENING TO MUSIC. You know, the stuff that's on the RECORDING.
So when you say that the dynamic range of the RECORDING needs to be on the order of 120dB to keep the noise from being AUDIBLE, you are in fact saying that a noise level of 4dB SPL, or not far above it, would be audible WHILE LISTENING TO MUSIC.
This is reinforced by your continued citing of the Ampex paper, which your 118dB figure is coming from.
The only way you can keep clinging to that figure is if you're arguing that noise levels at or just above 4dB SPL are audible WHILE LISTENING TO MUSIC. It's the only logical conclusion that can be reached given the claims you have made throughout this discussion.
So the only straw man I see here is your disingenuously calling my argument a straw man.
se
George, I am afraid that any result-oriented debate makes absolutely no sense in this thread. Despite that,
Re1: REW5 to measure room response, equalize basic room modes, stop at some 200Hz and do not try to get higher. REW5 and rePhase will make you an inverse filter, export impulse response and then use foobar convolver to play files.
REW - Room EQ Wizard Room Acoustics Software
rePhase | SourceForge.net
Re2: better thread is here
http://www.diyaudio.com/forums/solid-state/250272-current-drive-loudspeakers-45.html#post4216018
You may move forward, contrary to usual neverending debates on finding and swapping opamps, silver wires, contact switches, resistor types, quantum purifiers, germanium transitors etc. Real progress.
Why do you keep saying it "UNweighted," instead of "unweighted" as it is written in the text that you're "quoting"? You've done that each time so far. What's the emphasis for? Are you trying to impress someone with it? UNweighted. Yeah, that looks impressive. Compared to what, A-weighted?
And speaking of A-weighting, why do you leave out the text that immediately follows "115dB unweighted," which is "117dB A-weighted." A difference of just 2dB.
I find this emphasized use of "UNweighted" and the exclusion of the "A-weighted" figure very strange.
se
Umm... jj would be the last person Richard would want in this discussion.
And why are you so fond of jj? He's the one who gave us MP3.
se
Standard archival format .wav files, so where does the HD fit in? The desire to not further degrade any source when you archive it is admirable but this attachment is not aimed at original recordings with mikes, preamps, etc in front of the A/D.
The -115dB that keeps coming up is only the noise spec of the A/D which translates to 22.7nV/rt-Hz re a 1V full scale UNweighted, these days readily achievable. So what's the big deal? The ESS Saber A/D looks to do even the -118dB number.
Noise specs of Neumann U87 for reference.
Equivalent noise level, CCIR2) 26/23/25 dB1)
Equivalent noise level, A-weighted2) 15/12/14 dB-A1)
Signal-to-noise ratio, CCIR2) (rel. 94 dB SPL) 68/71/69 dB1)
Signal-to-noise ratio, A-weighted2) (rel. 94 dB SPL) 79/82/80 dB1)
Maximum SPL for THD 0.5%3) 117 dB (cardioid)
Maximum SPL for THD 0.5% with preattenuation3) 127 dB
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At what distance ?....I was thinking more in the context of a concert hall and a far back listening position.
Anyway, maybe not a good example.
Dan.
Thanks- my question was directed more at, "Do you know this guy who is a friend of mine who lives near you?" My interest in cars is somewhat less than zero.
I'm going elsewhere next week, probably drop in on SY.
Bottles already standing up. Will M be with you or is this solo?
Well, if you are well versed in reading mfr spec sheets.... many are Weighted numbers for noise. So be careful when comparing to referenced IASA UNweighted requirement.
THx-RNMarsh
PS - I havent hung myself yet - Got to get some coffee first this morning.
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The HD or now being called Hi Res fits in as downloads from lossless or WAV master files direct to the consumer. I am aware of the lower than converter only number in real apps. i pointed that out already, in fact. The example was CD of 96dB comes out closer to 90dB when you put it all together in a system. From my point of view -90 isnt quit good enough, however. So, the HiRes downloads may be better than CD and closer to what was put down on the master which should be darn near close to inaudible distortion and noise. It sure sounds good to my ears and look forward to more of it.
There is no big deal to me. I am not defending others (AES or IASA) numbers. But do point out that many if not most marketing spec sheet i see are weighted numbers and the ISAS is UNweighted number. So, is the Saber unweighted numbers?
Audible and inaudible --
View attachment Audible and Inaudible Problems with Digital Audio.pdf
THx-RNMarsh
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I wouldn’t think A weighting* would be applicable to audio electronics, while flat (un-weighted) or possibly C weighting (which is closer to your ears response) would be.
*A weighting while both now popular and misused, was an industrial spec which has the low end very much rolled off and hf some and was intended for sound levels under 90dB If I remember correctly.
Could a good / modern transformer fit in your super low noise system?
Finally, I get to point #2:
Well, noise isnt just the idle noise floor. We tend to seperate everything out as an individual number for engineering purposes. But the reality is that we hear it all together. Take the last page (11) from above as a case in point --- jitter can be also be seen as a noise. 1Khz signal with a 60psec jitter, the SNR is 128dB falling to 102dB at 20KHz. for 1.1 nesc of jitter at 20KHz we get 77dB SNR. We can add THD and IM to that noise etc etc etc. Combine it all and see if it is above audible thresholds.
THx-RNMarsh
Well, noise isnt just the idle noise floor. We tend to seperate everything out as an individual number for engineering purposes. But the reality is that we hear it all together. Take the last page (11) from above as a case in point --- jitter can be also be seen as a noise. 1Khz signal with a 60psec jitter, the SNR is 128dB falling to 102dB at 20KHz. for 1.1 nesc of jitter at 20KHz we get 77dB SNR. We can add THD and IM to that noise etc etc etc. Combine it all and see if it is above audible thresholds.
THx-RNMarsh
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Trying to follow this lively discussion let me see if I an pulling the gist of it out. What I think Richard is really alluding to is the fact that we want our electronics circuits to have a minimum of 118db range on the electronics side of things before they are converted from the D/A stage? I'm not following that we really need that much range in the acoustical realm, when we are actually listening to music. Am I getting this at all?
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