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Benchmark Media blog post about distortion
Benchmark Media blog post about distortion
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Old 21st November 2017, 04:09 AM   #1
Jim the Oldbie is offline Jim the Oldbie  United States
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Benchmark Media blog post about distortion
Default Benchmark Media blog post about distortion

Many (most?) of you may have already seen this, but just in case:

Benchmark Media: Interpreting THD Measurements

I do appreciate the way this company attempts to shovel away the BS with regard to high-end audio. I just wish I could afford to try some of their stuff.

Last edited by Jim the Oldbie; 21st November 2017 at 04:12 AM. Reason: mixing those damn metaphors again
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Old 21st November 2017, 04:39 AM   #2
Markw4 is online now Markw4  United States
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There are various things that could be said about that article. I would just note that not all pianos are stretch-tuned, although it does make them sound better (IMHO).
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Old 21st November 2017, 04:59 AM   #3
Jim the Oldbie is offline Jim the Oldbie  United States
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Benchmark Media blog post about distortion
Quote:
Originally Posted by Markw4 View Post
There are various things that could be said about that article.
Please do! That's why I started the thread! Well, that, and the fact that I've never started a thread here before, and so figured it was about time.

Quote:
I would just note that not all pianos are stretch-tuned, although it does make them sound better (IMHO).
I know more than one piano tuner who would go so far as to say that a piano that hasn't been stretch-tuned, hasn't been tuned.
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Old 21st November 2017, 10:10 AM   #4
DF96 is offline DF96  England
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It is a sales pitch thinly disguised as a technical article. However, the technical stuff appears to be sound although fairly basic. There is more to being a "geek" than knowing how to convert % to dB!
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Old 21st November 2017, 09:40 PM   #5
wwenze is offline wwenze  Singapore
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Faster solution: Just look at the FFT plot
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Old 21st November 2017, 09:46 PM   #6
Speedskater is online now Speedskater  United States
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That's a strange way of using 0dB SPL.
0dB SPL is the smallest mid-range sound that can be heard in the absence of other sounds under laboratory conditions. If there is a larger sound then it's near 0dB SPL THD is impossible to hear.
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Old 23rd November 2017, 04:03 PM   #7
DF96 is offline DF96  England
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I think all he was saying is that if distortion is below the theshold of hearing than it is by definition inaudible even without any masking. This may or may not be true. If it is true then sufficiently low distortion is inaudible, so the equipment would be audibly perfect (as far as nonlinear distortion is concerned). This can then be used to justify lots of 0's after the decimal point.

Two snags with this approach:
1. it assumes that there cannot be any 'anti-masking' i.e. a sound makes other sounds easier to hear - this may be true but I am not sure it has been exhaustively demonstrated
2. optimising one aspect of performance (in this case, nonlinear distortion) often means compromising on something else either because physics demands it or because the designer's attention was diverted
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Old 24th November 2017, 05:30 PM   #8
mmerrill99 is offline mmerrill99  United States
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Quote:
Originally Posted by DF96 View Post
I think all he was saying is that if distortion is below the theshold of hearing than it is by definition inaudible even without any masking. This may or may not be true. If it is true then sufficiently low distortion is inaudible, so the equipment would be audibly perfect (as far as nonlinear distortion is concerned). This can then be used to justify lots of 0's after the decimal point.

Two snags with this approach:
1. it assumes that there cannot be any 'anti-masking' i.e. a sound makes other sounds easier to hear - this may be true but I am not sure it has been exhaustively demonstrated
2. optimising one aspect of performance (in this case, nonlinear distortion) often means compromising on something else either because physics demands it or because the designer's attention was diverted
Yes, the part I bolded is true - it's called comodulated masking release which does exactly what it says on the tin - when another frequency synchronously modulates with a masked sound it un-masks the masked sound
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Old 24th November 2017, 06:27 PM   #9
Markw4 is online now Markw4  United States
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It seems like two different things people are talking about.

"Comodulated masking release" is an effect that reduces a masking effect in the masker is modulated. Comodulation Masking Release In Electric Hearing

However, DF96 suggested anti-masking would be an effect that would make a sound that was below the baseline threshold of hearing when unmasked, more audible in the presence of, or when summed with, an anti-masking sound. The idea there might be that a sound below the threshold of hearing might be inaudible by itself, but maybe adding it to another sound could result in a composite (summed) sound that makes the low level sound more audible. If one thinks about the waveforms both for individual sounds and the summed sound and the instantaneous SPL for each over time, for the summed signals the instantaneous SPL of the low level signal could at times be quite high (even though it's variation might be very small), perhaps at an absolute SPL that would make it more audible. If the anti-masker sound was chosen to minimize normal masking of the low level sound maybe it could work, I don't know. Also, I don't know if I explained the idea as I understand it very well. DF96, were you thinking of something like what I just described?
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Old 24th November 2017, 07:05 PM   #10
mmerrill99 is offline mmerrill99  United States
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Quote:
Originally Posted by Markw4 View Post
It seems like two different things people are talking about.

"Comodulated masking release" is an effect that reduces a masking effect in the masker is modulated. Comodulation Masking Release In Electric Hearing[

However, DF96 suggested anti-masking would be an effect that would make a sound that was below the baseline threshold of hearing when unmasked, more audible in the presence of, or when summed with, an anti-masking sound. The idea there might be that a sound below the threshold of hearing might be inaudible by itself, but maybe adding it to another sound could result in a composite (summed) sound that makes the low level sound more audible. If one thinks about the waveforms both for individual sounds and the summed sound and the instantaneous SPL for each over time, for the summed signals the instantaneous SPL of the low level signal could at times be quite high (even though it's variation might be very small), perhaps at an absolute SPL that would make it more audible. If the anti-masker sound was chosen to minimize normal masking of the low level sound maybe it could work, I don't know. Also, I don't know if I explained the idea as I understand it very well. DF96, were you thinking of something like what I just described?
There's a number of things to address in your reply but first I read DF96's text again & don't get the meaning from it that you do
"1. it assumes that there cannot be any 'anti-masking' i.e. a sound makes other sounds easier to hear - this may be true but I am not sure it has been exhaustively demonstrated"

From this I understood he was saying "is there an added sound which can unmask a sound "a sound makes other sounds easier to hear"? I can't see this referring to sounds below the ABSOLUTE threshold of audibility rather it concerns sounds which are being masked by noise or some other signal & therefore inaudible.

Sorry but the paper you linked does not state what you claim ""Comodulated masking release" is an effect that reduces a masking effect in the masker is modulated"

From the paper you linked "Comodulation masking release (CMR) is an improvement in the detection threshold of a masked signal that occurs when the masker envelopes are correlated across frequency (i.e., comodulation). CMR can be observed when flanking bands (FBs) of noise co-modulated with an on-frequency band (OFB) noise masker are added at remote frequencies (CMR1)"
Which is exactly what I stated! It's not about modulating the masker signal (CMR) but rather a signal at a different frequency (CMR1)

But your statement is also another form of CMR - where a decrease in masked thresholds occurs when the masker is amplitude-modulated. Comodulation Masking Release | Auditory Neuroscience

I'm not sure what you think he said but there is a related point - There is a whole area to be discussed about the relationship between dB, SPL & loudness perception. Perception of loudness is related to energy in the critical bands or ERB of the hearing mechanism. The consequence of this is that equal loudness curves from Flecther Munson are higher than equal loudness curves for noise.

In other words thresholds for noise are lower (by about 10dB, I think) than the F-M curves.

Why this is? Because the total energy in the ERB is higher for noise (mixed frequencies) than it is for pure tone that falls in the same ERB.

So can a number of inaudible tones that all fall into the same ERB become audible due to the total energy in that ERB becoming discernible?

Last edited by mmerrill99; 24th November 2017 at 07:12 PM.
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