The Audio Path In Consumer-Grade Products

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Pogre

Pogre

Audioholic Slumlord
On your last point, agreed.

Regarding Gene's versus JA's test lab environments and methodologies, the facts are that we just don't know. JA has been testing amps for years, and he sure has tested a lot of them. Does that mean the quality of the measurements are high? Not necessarily. We just don't have enough information to judge.

For example, Gene has not tested the same Emotiva amp that JA did, Gene tested the XPR-1 in 2013. In Gene's test report (oddly) he did not state a wide-band SNR, but the unweighted SNR at one watt with a 20KHz low-pass filter was 89db. That's in the range of what JA measured with the Benchmark amp, but JA didn't mention a low-pass filter, so I suspect Gene's result would have been worse without the filter. My point it that quibbling about a few db of measurement difference at these noise levels might be more due to measurement methodologies than what the true performance differences are.
So either way the differences are inaudible because both are outside our ability to detect them, if I'm following the discussion correctly? Better performance specs don't always translate to audible improvements and after a certain point, you're paying for build quality, high quality parts, reliability, etc., with little or no audible improvements? How much do you think would it skew the results by Gene applying that filter that JA didn't? A couple of db, or more?

At what point does snr become audible enough to be a problem?

Sorry for the rapid fire questions. I'm just trying to understand it better.

*Edit: I re-read your post. I can see how there are just too many variables to take into account as far as 2 different testing methodologies.
 
P

PENG

Audioholic Slumlord
I think an unweighted 110db SNR is remarkably high, in the I-don't-believe-it category.
The 110 dB unweighted figure I guessed was based on S&V's 130 dBA. Again, not that I did say I was guessing. In addition to "guessing", I should have stated the assumption, that S&V's measurement was done correctly. Like you, I do have my doubt.. Another thing to consider, we (I mean ADTG please pay attention:D) really should not compare SNRsGene measured on preamps directly to SNRs of power amps.

In the Denon's X3300W and other AVRs reviewed by AH, the "input drive" was 100 mV (for that Denon) and the output was 1 V rms, whereas in the review for integrated and power amplifiers he used different input drive voltage and at 1W output such as the case for the Yamaha A-S801
 
E

<eargiant

Senior Audioholic
Thank you all. It seems like you all confirmed that my line of thinking was correct.

Ultimately, to settle this SNR measurement kerfuffle, how do we go about getting Gene to measure a Benchmark AHB2? Seriously...I would like to see that.

A few points I'd like to clarify for the record.

In Gene's he did it with 100 mV input drive, 1V rms output and he measured the preamp output. How did Benchmark measured theirs?

The 128.5 dB I quoted was Stereophile's measurement not Benchmarks. According to JA he also used 100mV.

Interestingly, JA did confirm Benchmarks published specs by using the amps "lowest gain condition" which increased the SNR by about 3dB, as JA said "implying that the specified ratio was measured in that mode."

This also confirmed what I thought would be the case with lower gain (which was last question I asked Irv in post #203).

You are the one who try to compare them and said
I was not the one trying to compare them. I was illustrating a point. The view I had (which you again confirmed) is that you cannot compare them because they are not equivalent. It was ACDT Guy that originally compared the two disparate specs (Benchmark @1watt and Denon 3300 @Dynamic range). The point of me bringing the Yamaha into the mix was because it was measured @1 watt like JA did the Benchmark.


Yeah, but can we trust them to measure their own products, instead of independent 3rd party measurements? :D

What do you think of the Stereophile measurement of the Benchmark amp?
As noted above, I think that JA confirmed that Benchmark's published specs are accurate.
 
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AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
As noted above, I think that JA confirmed that Benchmark's published specs are accurate.
Stereophile measured the Benmark amp's unweighted SNR as 89dB. 22Hz-22kHz band was 106dB.

Benchmark spec said 130dB unweighted SNR. How's that accurate? :eek:
 
E

<eargiant

Senior Audioholic
Stereophile measured the Benmark amp's unweighted SNR as 89dB. 22Hz-22kHz band was 106dB.

Benchmark spec said 130dB unweighted SNR. How's that accurate? :eek:
Again- you're comparing disparate measurements and you also seem to have missed the part about the gain settings, so we just don't know. What we CAN compare is the measurement that was done in the same manner. See below.


Benchmark's published spec:

Rated output relative to output noise, inputs shorted

  • 132 dB A-weighted, Stereo Mode
Stereophile's measurement and comment:

Referenced to the AHB2's clipping power of 100W, this is equivalent to a dynamic range of 128.5dB, which is close to the specified 132dB. The S/N ratio did increase by around 3dB in the lowest-gain condition, implying that the specified ratio was measured in that mode.

So again, JA's 128.5dB + 3dB = 131.5 dB which is almost spot on to Benchmarks published 132 dB weighted specification.

 
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AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Again- you're comparing disparate measurements and you also seem to have missed the part about the gain settings, so we just don't know. What we CAN compare is the measurement that was done in the same manner. See below.


Benchmark's published spec:

Rated output relative to output noise, inputs shorted

  • 132 dB A-weighted, Stereo Mode
Stereophile's measurement and comment:

Referenced to the AHB2's clipping power of 100W, this is equivalent to a dynamic range of 128.5dB, which is close to the specified 132dB. The S/N ratio did increase by around 3dB in the lowest-gain condition, implying that the specified ratio was measured in that mode.

So again, JA's 128.5dB + 3dB = 131.5 dB which is almost spot on to Benchmarks published 132 dB weighted specification.
DYNAMIC RANGE is NOT the SAME thing as SNR.

READ: "a dynamic range of 128.5dB, which is close to the specified 132dB."

It did NOT say "a SNR of 128.5dB, which is close to the specified 132dB".

Oh, but I think I know what the issue here is now.

Benchmark spec has 2 sections:
1. "SNR and Dynamic Range"
2. "Noise Relative to 2.83 VRMS"

Is Benchmark telling people that SNR is the exact same thing as DYNAMIC RANGE? :eek:

Are they trying to confuse people with SNR vs Noise?

What's going on here?

The numbers listed for SNR are supposed to be for DYNAMIC RANGE, which is what Stereophile measured.

So the Benchmark Spec should read:
SNR = -109dB A-weighted Mono Mode
SNR = -112dB A-weighted Stereo Mode
Dynamic Range = 133dB Mono Mode
Dynamic Range = 130dB Stereo Mode


Hey, Irv, I think Benchmark uses the NEGATIVE (-) sign for SNR.

So, I guess Benchmark was close on their spec, but they just confused people with how they listed the spec by grouping "SNR and Dynamic Range" as the SAME THING and listing "NOISE" separately.

Will somebody please set us straight here with SNR, DYNAMIC RANGE, and NOISE?

Hmm, so then why didn't Benchmark list the Unweighted "Noise" number? They only listed the A-weighted "Noise" numbers.
 
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AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
So my impression is that Benchmark tries to MISLEAD people into believing that ACTUAL SNR is 133dBA, when it is ACTUALLY only 109dBA (A-weighted).

Dynamic Range (what is possible) is 133dBA. But SNR (what is actually achieved) is 109dBA.

And a SNR of 109dBA (A-Wt) can be achieved by a lot of cheap AVRs.

Do we care about what is possible or do we just care about what is actually achieved? :D
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
So my impression is that Benchmark tries to MISLEAD people into believing that ACTUAL SNR is 133dBA, when it is ACTUALLY only 109dBA (A-weighted).

Dynamic Range (what is possible) is 133dBA. But SNR (what is actually achieved) is 109dBA.

And a SNR of 109dBA (A-Wt) can be achieved by a lot of cheap AVRs.
Andy, I'm not sure what you're trying to accomplish here, other than some weird vendetta against Benchmark Media. I don't agree with everything they say either, but I just don't think they or any company matters that much in the big picture of audio and HT. Your multi-color high-emotion posts have actually got me to the point where I'm uncomfortable participating in this thread any further.
 
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P

PENG

Audioholic Slumlord
Ultimately, to settle this SNR measurement kerfuffle, how do we go about getting Gene to measure a Benchmark AHB2? Seriously...I would like to see that.
Email him if you know the address.


The 128.5 dB I quoted was Stereophile's measurement not Benchmarks. According to JA he also used 100mV.
Where did you get that? Below is the link to where I read about the 128.5 dB you probably are referring to.

https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier-measurements#KKllmKc7ofmgfhiA.99

The wideband S/N ratio, measured in the high-gain, stereo condition with the input shorted to ground and ref. 1W into 8 ohms, was very high, at 89.3dB. Reducing the measurement bandwidth to 22Hz–22kHz increased the ratio to 106dB, while switching an A-weighting filter into circuit increased it further, to 108.5dB. Referenced to the AHB2's clipping power of 100W, this is equivalent to a dynamic range of 128.5dB

So as ADTG pointed out before, that was dynamic range, not SNR. SNR, as measured by JA was 106 dB unweighted, and 108.5 dB A weighted, at 1W.

I know Irv doesn't believe in S&V's measurements but if we give S&V the benefit of doubt, at least we can say JA's A weighted numbers measured at clipping power of 100W are based on the same methodology as S&V, at least on paper.

Please also note that we cannot compare with JA's figures directly with S&V's on the AV8802A because once again, the Benchmark AHB2 is a power amp, not a prepro.

I was not the one trying to compare them.
Fair enough if you say so now, but in your post#205, you did say:

Here's another amp that Audioholics measured at a SNR of 90db but @ 1watt. Which I believe translates into an SNR that is markedly better than the AVR-3300." right?

The answer is, no, we don't know that, because Gene measured the pre-out of the Denon, and the power amp out of the Yamaha at 1W. I would guess the Yamaha is better but unlikely "markedly" better. My guess is based on Gene's measurements of other gear's pre-out, such as the $7500 Denon AVP and other expensive prepros and AVRs. Even compared to the results of those so called high end gear, the Denon AVR looks pretty good, within a few dB.


I was illustrating a point. The view I had (which you again confirmed) is that you cannot compare them because they are not equivalent. It was ACDT Guy that originally compared the two disparate specs (Benchmark @1watt and Denon 3300 @Dynamic range). The point of me bringing the Yamaha into the mix was because it was measured @1 watt like JA did the Benchmark.
Agree, I told him the same, that he shouldn't compare the SNR of preamp and power amp directly. I agree you can compare JA's unweighted SNR of the Benchmark to that of the Yamaha and the two appeared to be very comparable, both low enough to be inaudible by normal people.

As noted above, I think that JA confirmed that Benchmark's published specs are accurate.
Well, 128.5 vs 132 dB, that seems pretty close, accurate or not is sort of subjective though. Regardless, those numbers are still considered excellent.
 
P

PENG

Audioholic Slumlord
Again- you're comparing disparate measurements and you also seem to have missed the part about the gain settings, so we just don't know. What we CAN compare is the measurement that was done in the same manner. See below.


Benchmark's published spec:

Rated output relative to output noise, inputs shorted

  • 132 dB A-weighted, Stereo Mode
Stereophile's measurement and comment:

Referenced to the AHB2's clipping power of 100W, this is equivalent to a dynamic range of 128.5dB, which is close to the specified 132dB. The S/N ratio did increase by around 3dB in the lowest-gain condition, implying that the specified ratio was measured in that mode.

So again, JA's 128.5dB + 3dB = 131.5 dB which is almost spot on to Benchmarks published 132 dB weighted specification.
I wouldn't base it it on the lowest gain. Please note JA's comments:

"With the switch set to a sensitivity of "9.8V/22dBU," the gain was 9.2dB, which is appropriate for pro-audio sources but very low for domestic use. With the switch set to "4V/14.2dBU," the AHB2's gain was 17dB; with it set to "2V/8.2dBU," the gain was 22.9dB. This is still around 4dB lower than is usual for a domestic amplifier, but shouldn't be a problem with typical high-end preamplifiers and digital processors."

and

"The S/N ratio did increase by around 3dB in the lowest-gain condition, implying that the specified ratio was measured in that mode. However, I was surprised to find that the S/N decreased slightly when the amplifier was very hot."

Reading between the lines, JA called them out on this one. As I said, the AHB2 has measurements that make me want one, now, but it is only fair if we are to be so critical on AVRs measurements, we should apply the same standard, if not higher on separates too.
 
P

PENG

Audioholic Slumlord
So my impression is that Benchmark tries to MISLEAD people into believing that ACTUAL SNR is 133dBA, when it is ACTUALLY only 109dBA (A-weighted).

Dynamic Range (what is possible) is 133dBA. But SNR (what is actually achieved) is 109dBA.

And a SNR of 109dBA (A-Wt) can be achieved by a lot of cheap AVRs.

Do we care about what is possible or do we just care about what is actually achieved? :D
You have some misconception here, let me try to clarify (since Irv didn't do it..).

- JA's 128.5 dB is dynamic range at clipping power of 100W, so in that case Dynamic range = SNR measured at clipping power of 100W, presumably A weighted.

- SNR, if measured at 1W would be lower, as Irv pointed out long ago.

- DR, by definition, will be typically higher than SNR, if SNR is measured at 1W output, weighted or not.

- Some cheap AVRs may be able to achieve 109 dBA, but again most likely at rated power output, not at 1W output.
 
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P

PENG

Audioholic Slumlord
Gentlemen, I think we should all try to be more careful in interpreting specs and measurements. SNR, DR, power consumption, power output related terminologies may look simple but not as always straight forward for apple to apple comparisons.

I felt okay to say I don't know (appreciate Irv did exactly that in one of his response to the OP) and "my mistake".
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
The wideband S/N ratio, measured in the high-gain, stereo condition with the input shorted to ground and ref. 1W into 8 ohms, was very high, at 89.3dB. Reducing the measurement bandwidth to 22Hz–22kHz increased the ratio to 106dB, while switching an A-weighting filter into circuit increased it further, to 108.5dB. Referenced to the AHB2's clipping power of 100W, this is equivalent to a dynamic range of 128.5dB

So as ADTG pointed out before, that was dynamic range, not SNR. SNR, as measured by JA was 106 dB unweighted, and 108.5 dB A weighted, at 1W.

- JA's 128.5 dB is dynamic range at clipping power of 100W, so in that case Dynamic range = SNR measured at clipping power of 100W, presumable A weighted.
Let me see if I understand this DR vs SNR. Maybe I learned something new today. :D

1. SNR @ 1w Power is not the same thing as Dynamic Range.
2. SNR @ Clipping power is the same thing as Dynamic Range?

3. When compare SNR, we are usually comparing SNR @ 1w/2.83v/8 ohms/20Hz-20kHz or 10Hz-24kHz ?

4. We can't compare SNR between AVRs and Amps because the SNR on AVRs are usually done on the Preamp Section, not the Amp section?
 
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Pogre

Pogre

Audioholic Slumlord
Gentlemen, I think we should all try to be more careful in interpreting specs and measurements. SNR, DR, power consumption, power output related terminologies may look simple but not as always straight forward for apple to apple comparisons.

I felt okay to say I don't know (appreciate Irv did exactly that in one of his response to the OP) and "my mistake".
I'm just gonna stfu and keep reading. You guys are discussing things waaaay over my head, but I like reading about it regardless. There is so much more that goes into sound reproduction than I could have imagined. It's fascinating to me.
 
Swerd

Swerd

Audioholic Warlord
Wikipedia has some basic textbook information and definitions that could clear up this confusion. The definitions are, of course, expressed properly in math. Its the verbal interpretations of those definitions that lead to most of the confusion.

Dynamic range (of audio)

Signal-to-Noise ratio definition

Audio Systems measurements
On that page, scroll down to see the paragraph titled "Dynamic range and Signal-to-Noise ratio":

Dynamic range and Signal-to-Noise ratio
The difference between the maximum level a component can accommodate and the noise level it produces. Input noise is not counted in this measurement. It is measured in dB.

Dynamic range refers to the ratio of maximum to minimum loudness in a given signal source (e.g., music or program material), and this measurement also quantifies the maximum dynamic range an audio system can carry. This is the ratio (usually expressed in dB) between the noise floor of the device with no signal and the maximum signal (usually a sine wave) that can be output at a specified (low) distortion level.

Since the early 1990s it has been recommended by several authorities including the Audio Engineering Society that measurements of dynamic range be made with an audio signal present. This avoids questionable measurements based on the use of blank media, or muting circuits.

Signal-to-noise ratio (SNR), however, is the ratio between the noise floor and an arbitrary reference level or alignment level. In "professional" recording equipment, this reference level is usually +4 dBu (IEC 60268-17), though sometimes 0 dBu (UK and Europe - EBU standard Alignment level). 'Test level', 'measurement level' and 'line-up level' mean different things, often leading to confusion. In "consumer" equipment, no standard exists, though −10 dBV and −6 dBu are common.

Different media characteristically exhibit different amounts of noise and headroom. Though the values vary widely between units, a typical analog cassette might give 60 dB, a CD almost 100 dB. Most modern quality amplifiers have >110 dB dynamic range, which approaches that of the human ear, usually taken as around 130 dB.​
 
P

PENG

Audioholic Slumlord
Let me see if I understand this DR vs SNR. Maybe I learned something new today. :D

1. SNR @ 1w Power is not the same thing as Dynamic Range.
2. SNR @ Clipping power is the same thing as Dynamic Range?

3. When compare SNR, we are usually comparing SNR @ 1w/2.83v/8 ohms/20Hz-20kHz or 10Hz-24kHz ?

4. We can't compare SNR between AVRs and Amps because the SNR on AVRs are usually done on the Preamp Section, not the Amp section?
1. Correct, different by definition.

2. Still different by definition but same value under that condition, for practical purposes.

3. If not specified, you really won't know for sure, but you can guess if you wish.

4. For AVR and integrated, I don't think you should generalize, AH seemed to do the preouts (for avrs) only. S&V does theirs on the power amp output. Even then I used the word "seemed" because I have not read every AH reviews on AVRs.

Edit: I have read many more AH reviews and found that in the past Gene had in fact measured both the preouts and speaker outputs of a few AVRs and integrated.
 
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P

PENG

Audioholic Slumlord
Again, I'm just trying to understand this SNR/DR spec,

From S&V of Yamaha 377:

"THD+N from the Audio input to the speaker output was less than 0.022% at 1 kHz when driving 2.83 volts into an 8-ohm load. Crosstalk at 1 kHz driving 2.83 volts into an 8-ohm load was –77.36 dB left to right and –77.27 dB right to left. The signal-to-noise ratio with an 8-ohm load from 10 Hz to 24 kHz with “A” weighting was –110.89 dBrA."

I assume 2.83v is usually 1w (that's why sensitivity is in dB/2.83v/m or dB/1w/m) ?

If so, they mentioned the 2.83v for THD and Crosstalk, but didn't mention the 2.83v for SNR.

Is this why we can't assume the SNR was also at 2.83v, even though they mentioned the 2.83v for THD & Crosstalk right before talking about the SNR?

So S&V should have said, "The SNR was 110dBA w/ 8 ohms load, 2.83v, from 10 Hz- 24 kHz" ?
2.83v is 1 watt only if the load is 8 ohm.

If the SNR is measured at 1W, you don't need to worry about the voltage and ohm.

In this case there are pros and cons in using 2.83v and 1 watt. As long as you compare apple to apple either way is fine.
 
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