The Audio Path In Consumer-Grade Products

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<eargiant

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Irvrobinson

Irvrobinson

Audioholic Spartan
I think that's a pretty damn good circuit analysis, and it makes good technical sense. Compared to that nonsense on another link you posted from Benchmark about digital inter-sample overs, this one is excellent. I suspect the circuit differences they describe result in fully measurable advantages, but the real question is, are they audible? My guess would be that with the ATI3000 amp I use, on the balanced inputs, which have a gain of 28db, the answer would be maybe. It would be nicer to have more output than 2.4v if you have inefficient speakers in a very large room, and you like to listen at high volume levels. Otherwise, I doubt it.

I use a Benchmark HDR as a preamp-DAC in my music system, and it does run hot. It's unlikely a pre-pro designer would allow himself so much power dissipation and heat for so little circuitry, not to mention a bunch of expensive higher-voltage components. There's some logic to that blog post. For someone like me, yeah, I dislike cheap circuits enough to spend money on things like Benchmark preamp-DACs. To someone else, I could understand if the conclusion was that it wasn't a compelling argument.
 
TheWarrior

TheWarrior

Audioholic Ninja
I came across this write-up on Benchmark's website:

https://benchmarkmedia.com/blogs/application_notes/19947905-the-audio-path-in-consumer-grade-audio-products

I know that John and Jeff's take on AVR sound quality (even TOTL models) is highly contested on Audioholics but since most here seem to rely on science and measurable facts, I was wondering if anyone was in disagreement with the facts they present. Is anyone swayed by this or are those guys just full of it?
Looks like relevant information, but the details of input/output gain and voltage presuppose you have speakers that can extract 'better' sound from the ideal conditions that they suggest.

Once I get my center/surround speakers built, maybe I'll consider something like the Yamaha CX5100 thanks to it's top quality DAC's on each channel. But there is the problem with this addiction: there's always a new upgrade!
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I think they are so full of it.

Here are some MEASURABLE FACTS of the Marantz AV8802:

Response from the multichannel input to the main output measures –0.04 dB at 20 Hz, –0.01 dB at 20 kHz.

The analog THD+N was less than 0.008% at 1 kHz with a 100-millivolt input and the volume control set to 82.5.

Crosstalk with a 100-mV input was –92.21 dB left to right and –93.16 dB right to left.

The signal-to-noise ratio with “A” weighting was –130.38 dBrA.

https://www.soundandvision.com/content/marantz-av8802-surround-processor-review-test-bench

That article from Benchmark mentions a lot about SNR. I don't think you can get much better than a SNR of 130dB. Certainly not audible.
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
I think they are so full of it.

Here are some MEASURABLE FACTS of the Marantz AV8802:

Response from the multichannel input to the main output measures –0.04 dB at 20 Hz, –0.01 dB at 20 kHz.

The analog THD+N was less than 0.008% at 1 kHz with a 100-millivolt input and the volume control set to 82.5.

Crosstalk with a 100-mV input was –92.21 dB left to right and –93.16 dB right to left.

The signal-to-noise ratio with “A” weighting was –130.38 dBrA.

https://www.soundandvision.com/content/marantz-av8802-surround-processor-review-test-bench

That article from Benchmark mentions a lot about SNR. I don't think you can get much better than a SNR of 130dB. Certainly not audible.
Actually, Andy, that test report is more suspect than the circuit analysis. A-weighting has been deprecated for years because it produces an artificially better result than other methods, and is preferred only by product marketing groups. A-weighting often hides issues that unweighted measurements reveal. Personally, I never look at weighted SNRs. That's one thing I really like about Gene's reviews, he measures and reports unweighted SNRs for AVRs and amplifiers. The Denon AVR-X3300W, for example, according to Gene, has only a 90db unweighted SNR to the pre-amp outputs. That's actually a very good measurement, but I suspect it is not as good as Benchmark achieves. Is the difference audible? Frankly, I doubt it, but you're the one quoting measurements.

Measuring crosstalk at 100mv is also a bit of manipulation. It should be measured at 1v to tell you something interesting, assuming crosstalk is interesting. Even if crosstalk was -70db I'm not sure it is, though I wouldn't be surprised in an AVR if it measured -50db at 1v.

If this were pharmacology you'd be all over this sort of measurement manipulation.
 
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AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Actually, Andy, that test report is more suspect than the circuit analysis. A-weighting has been deprecated for years because it produces an artificially better result than other methods, and is preferred only by product marketing groups. A-weighting often hides issues that unweighted measurements reveal.

...Denon AVR-X3300W, for example, according to Gene, has only a -90db unweighted SNR...
A-weighting is usually about 20dB better than unweighted. So a SNR of -130dBA is about -110dB unweighted.

Even if the AV8802's SNR were -100dB unweighted, it would still be excellent.

The Denon AVP-A1HDCI PrePro has an unweighted SNR of -95dB.

The Denon X3300's SNR of -90dB unweighted is also excellent.

I can imagine what those guys at Benchmark has to say about the Denon X3300 or any AVR.

They are full of it if they claim to hear the difference in these SNR values.
 
BoredSysAdmin

BoredSysAdmin

Audioholic Slumlord
I think that's a pretty damn good circuit analysis, and it makes good technical sense. Compared to that nonsense on another link you posted from Benchmark about digital inter-sample overs, this one is excellent. I suspect the circuit differences they describe result in fully measurable advantages, but the real question is, are they audible? My guess would be that with the ATI3000 amp I use, on the balanced inputs, which have a gain of 28db, the answer would be maybe. It would be nicer to have more output than 2.4v if you have inefficient speakers in a very large room, and you like to listen at high volume levels. Otherwise, I doubt it.

I use a Benchmark HDR as a preamp-DAC in my music system, and it does run hot. It's unlikely a pre-pro designer would allow himself so much power dissipation and heat for so little circuitry, not to mention a bunch of expensive higher-voltage components. There's some logic to that blog post. For someone like me, yeah, I dislike cheap circuits enough to spend money on things like Benchmark preamp-DACs. To someone else, I could understand if the conclusion was that it wasn't a compelling argument.
I'm not an EE, but I did spend few years studying the field in some depth and worked as Electronics technician for 3 years.
I feel that despite the analysis is in-depth, but I question author conclusion. Reducing circuit power level could introduce more noise and lower the SNR, but not necessarily so if properly routed and/or insulated.
I think that no one arguing that running fully discrete and balanced signal processing is better way to go to guarantee superior noise rejection but Irv very accurately said - "are they audible?"
Can you really with straight face tell the difference between 110db SNR and 115db SNR
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
From Stereophile measurement of the Benchmark AHB2 Amp:

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

...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....

Wow. Mind blowing SNR numbers there. So full of it.

Benchmark claimed that the A-Weighted SNR is 132dB. Yet Stereophile measured only 108dB A-Weighted.

I'm thinking Benchmark lie about their specs!

$3,000 Benchmark 100WPC stereo amplifier A-Weighted SNR = 108dBA.

$300 Yamaha AVR A-Weighted SNR = 110dBA .

How humiliating!!!

https://www.soundandvision.com/content/yamaha-rx-v377-av-receiver-test-bench
 
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Swerd

Swerd

Audioholic Warlord
… I suspect the circuit differences they describe result in fully measurable advantages, but the real question is, are they audible?
Thank you for stating what should be the obvious question. Without audible improvements, improved circuitry becomes engineering without a function.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
A-weighting is usually about 20dB better than unweighted. So a SNR of -130dBA is about -110dB unweighted.

Even if the AV8802's SNR were -100dB unweighted, it would still be excellent.

The Denon AVP-A1HDCI PrePro has an unweighted SNR of -95dB.

The Denon X3300's SNR of -90dB unweighted is also excellent.

I can imagine what those guys at Benchmark has to say about the Denon X3300 or any AVR.

They are full of it if they claim to hear the difference in these SNR values.
Sometimes they are full of it, but I think that circuit analysis was very well done.

There isn't a rule of thumb for unweighted versus A-weighted SNR measurements. Since they're frequency dependent you can't count on anything. IMO, unweighted SNRs tell you the most about designs overall, and A-weighted tells you very little about overall product quality.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
I'm not an EE, but I did spend few years studying the field in some depth and worked as Electronics technician for 3 years.
I feel that despite the analysis is in-depth, but I question author conclusion. Reducing circuit power level could introduce more noise and lower the SNR, but not necessarily so if properly routed and/or insulated.
I think that no one arguing that running fully discrete and balanced signal processing is better way to go to guarantee superior noise rejection but Irv very accurately said - "are they audible?"
Can you really with straight face tell the difference between 110db SNR and 115db SNR
The voltage of a circuit does directly relate to the difficulty of achieving good broadband SNRs, but you can't just take the same circuit, strap it to two different voltages, and assume you're going to measure a better SNR with the higher voltage version. On the other hand, the analysis and commentary in the blog were in my opinion valid. I know some people don't want to hear it, but packing a lot of complex circuits and parts that make up a modern pre-pro into a modest package at a certain price point (actually, a cost point) is going to result in a slew of compromises. That's the part I agree with. And, keep in mind, Benchmark is comparing a video-capable pre-pro to one of their simple-by-comparison preamp-DACs, where the Benchmark product costs almost as much as a top of the line pre-pro.

Interestingly, my cheap Outlaw 975 pre-pro has some of the exact issues that the Benchmark blog talks about.
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
From Stereophile measurement of the Benchmark AHB2 Amp:

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

...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....

Wow. Mind blowing SNR numbers there. So full of it.

Benchmark claimed that the A-Weighted SNR is 132dB. Yet Stereophile measured only 108dB A-Weighted.

I'm thinking Benchmark lie about their specs!

$3,000 Benchmark 100WPC stereo amplifier A-Weighted SNR = 108dBA.

$300 Yamaha AVR A-Weighted SNR = 110dBA .

How humiliating!!!

https://www.soundandvision.com/content/yamaha-rx-v377-av-receiver-test-bench
Who are you trying to convince, Andy, us or yourself?
 
E

<eargiant

Senior Audioholic
From Stereophile measurement of the Benchmark AHB2 Amp:

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

...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....

Wow. Mind blowing SNR numbers there. So full of it.

Benchmark claimed that the A-Weighted SNR is 132dB. Yet Stereophile measured only 108dB A-Weighted.

I'm thinking Benchmark lie about their specs!

$3,000 Benchmark 100WPC stereo amplifier A-Weighted SNR = 108dBA.

$300 Yamaha AVR A-Weighted SNR = 110dBA .

How humiliating!!!

https://www.soundandvision.com/content/yamaha-rx-v377-av-receiver-test-bench
You conveniently left these parts out:

"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."

and

"However, the Benchmark amplifier's specifications are close to those of my Audio Precision system, both regarding the purity of its signal generator and the dynamic range of its analyzer. Correctly characterizing the AHB2's measured performance would therefore present a challenge. And, to my embarrassment, one of the speaker cables with which I routinely measure amplifiers and my test load set to 4 ohms were also introducing small amounts of nonlinearity. These problems—and here I'm talking about the difference between 0.0003% THD+noise and 0.0005%—haven't affected the measured performance of other amplifiers I've tested, but they were detectable with the AHB2's very low intrinsic distortion and noise."

Try that with the Yamaha. Trust me I know, I have the Yamaha A-S801 which I think is better (no doubt equivalent) to that $300 AVR.

I suggest you take Benchmark up on their 30 Day Risk Free Trial offer and order the DAC3 and AHB2 combo and give them a whirl.

I suspect you'll stop humiliating yourself by posting nonsense like this.
 
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ski2xblack

ski2xblack

Audioholic Samurai
Benchmark really should consider packing a few more of those noisy complex circuits and parts under the hood. Bass management and PEQ would be a worthy trade-off for raising the noise floor, IMO. They have plenty of wiggle room, starting from -132db. Am I off my rocker for thinking so? They do that and I'll take mine in black, svp. Perfect for the more sensitive speakers in my collection.
 
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AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
You conveniently left these parts out:

"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."
Are you saying SNR is the same thing as DYNAMIC RANGE ?

I am focusing only on SNR because it seems the article by Benchmark mentions SNR about 4 or more times, making it sound like SNR of the Marantz PrePros is LOW when in fact it is -130dBA, which is a lot higher than the -108dBA of the Benchmark amp!

Again, just looking at SNR (because the article significantly talks about SNR), not Dynamic Range, even a $300 AVR has a higher A-Wt SNR than the Benchmark!
 
E

<eargiant

Senior Audioholic
Thank you for stating what should be the obvious question. Without audible improvements, improved circuitry becomes engineering without a function.
I'm less than an ear giant but I can tell when an amp/pre combo has a very high SNR. The complete silence or as they say the "ink black background" is a trait I seek.

Something nobody has really covered in this thread is Gain. While higher gain on a pre-amp can sound good and even enjoyable. The purest, cleanest most accurate sound is going to come with a lower gain setting. Just my experience.
 
E

<eargiant

Senior Audioholic
Are you saying SNR is the same thing as DYNAMIC RANGE ?

I am focusing only on SNR because it seems the article by Benchmark mentions SNR about 4 or more times, making it sound like SNR of the Marantz PrePros is LOW when in fact it is -130dBA, which is a lot higher than the -108dBA of the Benchmark amp!
Just order one, you'll see.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Thank you for stating what should be the obvious question. Without audible improvements, improved circuitry becomes engineering without a function.
IMO, NO audible improvements = NO engineering.:D
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Just order one, you'll see.
Just answer the question for jury! :D

Is Dynamic Range the SAME THING as Signal-to-Noise-Ratio?

Yes or No?

If NO, then is it true that the $300 Yamaha has BETTER A-Wt SNR than the $3,000 Benchmark ?

Is -110dBA better than -108dBA?

I rest my case. :D
 
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