The Audio Path In Consumer-Grade Products

[AcuDefTechGuy]

Yeah, but you've got to know enough about measurements to put them in context. I'm as big a fan as anyone here of measurements, but when I see a review with one-line statements with a few unqualified measurements, especially on electronics, I pretty much disregard them as I do with subjective prose.

After I purchased the Outlaw 975 pre-pro I've had some performance issues with I saw some rave reviews for it, complete with measurements. It's not enough to quote simple numbers; it takes understanding to know what they mean, and in some cases I know that I don't know enough to know what they mean.

Not all measurements are created equal for sure. It would be nice if Gene could measure every single component in the world. But some of us "make do" with what we have because it is better than someone's colorful verbiage.

So you're completely dismissing the measurements (FR, THD, Crosstalk, SNR) because it's not comprehensive enough?

To you, all these limited measurements from Home Theater Magazine/Sound & Vision Magazine are worthless?

 

[Irvrobinson]

Not all measurements are created equal for sure. But some of us "make do" with what we have because it is better than someone's colorful verbiage.

So you're completely dismissing the measurements because it's not comprehensive enough?

To you, all these limited measurements from Home Theater Magazine/Sound & Vision Magazine are worthless?

And all we have left are 100% subjective opinions?

Yes, I'm dismissing measurements that are taken completely out of context. I think they're useless, and, frankly, I don't even trust them. Like for starters, the top of the line Audio Precision analyzer, the APx555, has an advertised THD + SNR of 117db. So how does one achieve a "measured" result of 132db?

Like I said, that's what I really like about Gene's measurements sections, he gives you unweighted measurements, the real charts and graphs in readable scale and format, and he explains what and how he measured. John Atkinson does that too. Peter Aczel did some of that too, but got lazy about it when he became convinced that the measurements were irrelevant beyond a certain point.

 

[AcuDefTechGuy]

Yes, I'm dismissing measurements that are taken completely out of context. I think they're useless, and, frankly, I don't even trust them. Like for starters, the top of the line Audio Precision analyzer, the APx555, has an advertised THD + SNR of -117db. So how does one achieve a "measured" result of -132db?

Like I said, that's what I really like about Gene's measurements sections, he gives you unweighted measurements, the real charts and graphs in readable scale and format, and he explains what and how he measured. John Atkinson does that too. Perter Aczel did some of that too, but got lazy about it when he became convinced that the measurements were irrelevant beyond a certain point.

No one is arguing that comprehensive measurements from Audioholics (Gene) is gold standard. We all want that.

But most components don't have measurements from Audioholics and Stereophile.

Some of us believe that without these comprehensive measurements, all we have left to choose from are measurements from S&V Magazine.

 

[killdozzer]

For years the earliest human, Australopithecus afarensis was known to have existed 3.2 million years ago. She held the record for quite a while. The mantle has been taken over by Ardipithecus ramidus so the human timeline has been pushed back to 4.4 million years.

I see you're under the impression you gave me one, so this might come as a surprise; I still say Australopithecus is really not the argument you should be making. Let's be grown ups, I miss that. It's your call, of course.

I'm partly to blame since I wasn't specific enough; I didn't mean any homo- no matter what. I meant sapiens, I'm sorry for not making that clear. (it's far less then) Australopithecus went extinct, probably because they sucked at being audiophiles. (just kidding, don't get mad) To think you could draw direct heritage of the spatial orientation through sound basing it on few bones would be a discovery of the millennia (eon even). To then think some audio companies utilise this sound orientation in the manufacturing of their equipment is probably as scientific as AudioQuest.

Although I don't agree with you, I know what it means to talk to 15-20 members at the same time, all coming from all sides and against you.

So I accept some "spikes" on your side.

I don't mean to be rude and my post was trying to draw your attention to a certain difference that exists among your first post and what you write on, for example, pages 5 and 6. This difference plots a course and it's not going anywhere particularly nice.

I'll give it one more shot and I'm not provoking you, really:

This forum site is not producing ill content noobs. What are you trying to fix?? It is not broken.

People here simply like to combine data, specs and measurements with auditioning and listening and they make decisions based on that. AND! they are happy for the most part.


WHAT is bugging you? Why do you want people here to adopt your ways??? Why are you imposing? Honestly, your motives are not clear.

 

[Irvrobinson]

No one is arguing that comprehensive measurements from Audioholics (Gene) is gold standard. We all want that.

But most components don't have measurements from Audioholics and Stereophile.

Some of us believe that without these comprehensive measurements, all we have left to choose from are measurements from S&V Magazine.

And I'm just putting the euphoria about measurements in context. There's BS in measured data too. Do as you will, I just ignore S&V.

I might also bring up an example of a Velodyne sub review I once asked about in a thread on AH a long time ago:

http://hometheaterhifi.com/reviews/speaker/subwoofers/velodyne-dd18-subwoofer/

Full of great-looking measurements, right? I know something of electronics, but I don't know much about speaker design or measurement. Josh Ricci basically said the measurements in the review were BS, and while he still liked the DD18+, his measurements looked a lot different. It was a very enlightening discussion. What I'm saying is that it takes knowledge and context to know whether measurements are valid, or even believable, and holding them up as some sort of gold standard for comparing products is not all that productive, in my opinion. I know that valid measurements and expert interpretation are hard to come by, but that doesn't mean the next best thing is any measurement available.

 

[Bucknekked]

I would own Rolex watches just for the heck of it if I were a billionaire.

There's nothing wrong with owning expensive DAC or separates vs AVR. Whatever makes you happy. You don't need to justify it. Just do it.

We are sharing our personal experiences.

But if we're relying on science (double-blind testing) and measurements, you're not going to win the debate.

If the speakers (tweeters of Al, Mg, Ti, Be, Diamond, Silk, RAAL, AMT, etc.) and electronics measure superbly, how can people debate that one type is better?

Or better ONLY for certain venues (classical music, rock, pop, jazz, etc.) ?

I have owned several Rollexes. I didnt have to justify them to anybody. Loved them.

Same with audio. This is discretionary stuff all the way. By all means, buy what makes you smile when you turn it on. We trade barbs and opinions here on the AH, but i think most people here keep things in perspective.

I like @Pogre s perspective: twin 15 inch Hsu subwoofers. Heck ya.

 

[Irvrobinson]

And one more thing. While many in this thread are dissing Benchmark for one thing or another, including me over that inter-sample overs blog entry, they are one of the few manufacturers that include a full set of measurements, more comprehensive than I've seen in most reviews, right in the owners manual for every product. Here's an example:

https://cdn.shopify.com/s/files/1/0321/7609/files/DAC3_Series_Manual_Rev_B.pdf?9982830537634228604

The measurements start on page 46.

Benchmark is actually a role model for other companies in this regard, IMO.

 

[AcuDefTechGuy]

..they are one of the few manufacturers that include a full set of measurements...

Wait......You mean they perform their OWN.......measurements in their OWN.......room and include their OWN........measurements in their own...manual?

When we talk about measurements, most of us are talking about INDEPENDENT THIRD PARTY UNBIASED measurements, not measurements done by the companies themselves.

 

[AcuDefTechGuy]

Here is their manual for their Amp:

https://cdn.shopify.com/s/files/1/0321/7609/files/AHB2_Manual_-_Rev_G.pdf?6581480924542235084

I don't see any SNR measurements. I thought SNR was so important to them in their article?

I was hoping to compare their OWN SNR measurement to 3rd party Stereophile.

According to Stereophile, the Amp's unweighted wide-band SNR was 89dB and A-weighted SNR was 108dB.

 

[Irvrobinson]

Here is their manual for their Amp:

https://cdn.shopify.com/s/files/1/0321/7609/files/AHB2_Manual_-_Rev_G.pdf?6581480924542235084

I don't see any SNR measurements. I thought SNR was so important to them in their article?

I was hoping to compare their OWN SNR measurement to 3rd party Stereophile.

According to Stereophile, the Amp's unweighted wide-band SNR was -89dB and A-weighted SNR was -108dB.

Ha! Good find.

But... you can't compare Benchmark's specs in this particular case directly with Stereophile's measurements. (I meant to explain that yesterday, but forgot.) If you can tell me why that is the case I'll give you a special prize.

 

[panteragstk]

Wow. Finally got all the way through this thread.

My question when it comes to measurements is this: At what measured point do certain specs become irrelevant? I'll use SNR as the example. If the un-weighted SNR is -118db for one amp and another somehow is better at -132db does it even matter? Those are obviously both great, but aren't we getting to the point of diminishing returns? If not, at what point does audibility stop?

I hope I'm asking that the right way.

 

[Pogre]

Wow. Finally got all the way through this thread.

My question when it comes to measurements is this: At what measured point do certain specs become irrelevant? I'll use SNR as the example. If the un-weighted SNR is -118db for one amp and another somehow is better at -132db does it even matter? Those are obviously both great, but aren't we getting to the point of diminishing returns? If not, at what point does audibility stop?

I hope I'm asking that the right way.

Not according to millions of years of evolution.

 

[AcuDefTechGuy]

Wow. Finally got all the way through this thread.

My question when it comes to measurements is this: At what measured point do certain specs become irrelevant? I'll use SNR as the example. If the un-weighted SNR is 118db for one amp and another somehow is better at 132db does it even matter? Those are obviously both great, but aren't we getting to the point of diminishing returns? If not, at what point does audibility stop?

I hope I'm asking that the right way.

Irv, PENG, and others have also raised the question of audibility throughout this thread.

I think it's not audible when we are talking about unweighted SNR of 60dB or A-weighted SNR of 90dB.

 

[Swerd]

My question when it comes to measurements is this: At what measured point do certain specs become irrelevant? I'll use SNR as the example. If the un-weighted SNR is -118db for one amp and another somehow is better at -132db does it even matter? Those are obviously both great, but aren't we getting to the point of diminishing returns? If not, at what point does audibility stop?

Good point.

Many things, especially in engineering, become a question of what is good enough? SNR of an amp is a good example. If ~90-95 dB is good enough for excellent audio, does 118 or 132 dB matter? No, it could only add to the cost, but probably does not make a functional difference.

The hard part is determining what level is good enough and what level is overkill.

 

[Irvrobinson]

Wow. Finally got all the way through this thread.

My question when it comes to measurements is this: At what measured point do certain specs become irrelevant? I'll use SNR as the example. If the un-weighted SNR is -118db for one amp and another somehow is better at -132db does it even matter? Those are obviously both great, but aren't we getting to the point of diminishing returns? If not, at what point does audibility stop?

I hope I'm asking that the right way.

IMO, the answer is: it depends. For example, for amplifiers, it is very important to know the power level that the SNR is measured relative to. (This is why Stereophile's measurements are not directly comparable to Benchmark's specs.) Most manufacturers like Benchmark, including ATI incidentally, quote SNRs for amplifiers relative to rated power output, while John Atkinson (and Gene) measure SNR relative to one watt. I dislike SNR measurements referenced to rated power, for a lot of reasons, not the least of which is that it's a marketing trick for producing a higher number as a figure of merit, just like A-weighting does, but it's worse because every amp has different gain and rated power, and because amps typically don't run at rated power. That's why one watt unweighted SNRs for amps make the most sense - because one watt is a realistic power level for actual use, and every amp is measured at the same level.

Noise, unlike distortion, is mostly a constant value regardless of output, and most absolute measurements I've seen are in microvolts, and IMO are best plotted in a microvolt scale across a frequency spectrum. That's cumbersome, so broad-spectrum unweighted SNRs are the convenient figure of merit.

So, for unweighted 1W SNRs, 75db is a very good measurement. I think about 97db is the best I've ever seen (not that I've looked much lately). I've seen amps with measurements as low as 57db. Is there an audible difference between amps at 57db, 75db, and 97db? Maybe. It might depend on the speakers.

If you use very sensitive speakers, let's say 95db/2.83v/1meter, since noise is mostly a constant in the amp, and sensitive speakers need much less output, in this case 10-12db less power than a typical speaker, it is possible that a better noise spec could make an audible difference in quiet passages. I have to admit I doubt it even at 57db, but I'd bet $100 that at 75db it was never more audible than 97db. Would I rather own the 97db@1W amp? Absolutely. Is such a low noise spec audible? I really doubt it, especially with more typical speakers.

 

[panteragstk]

Good point.

Many things, especially in engineering, become a question of what is good enough? SNR of an amp is a good example. If -90-95 dB is good enough for excellent audio, does -118 or -132 dB matter? No, it could only add to the cost, but probably does not make a functional difference.

The hard part is determining what level is good enough and what level is overkill.

That's what I'm wondering.

IMO, the answer is: it depends. For example, for amplifiers, it is very important to know the power level that the SNR is measured relative to. (This is why Stereophile's measurements are not directly comparable to Benchmark's specs.) Most manufacturers like Benchmark, including ATI incidentally, quote SNRs for amplifiers relative to rated power output, while John Atkinson (and Gene) measure SNR relative to one watt. I dislike SNR measurements referenced to rated power, for a lot of reasons, not the least of which is that it's a marketing trick for producing a higher number as a figure of merit, just like A-weighting does, but it's worse because every amp has different gain and rated power, and because amps typically don't run at rated power. That's why one watt unweighted SNRs for amps make the most sense - because one watt is a realistic power level for actual use, and every amp is measured at the same level.

Noise, unlike distortion, is mostly a constant value regardless of output, and most absolute measurements I've seen are in microvolts, and IMO are best plotted in a microvolt scale across a frequency spectrum. That's cumbersome, so broad-spectrum unweighted SNRs are the convenient figure of merit.

So, for unweighted 1W SNRs, -75db is a very good measurement. I think about -97db is the best I've ever seen (not that I've looked much lately). I've seen amps with measurements as low as -57db. Is there an audible difference between amps at -57db, -75db, and -97db? Maybe. It might depend on the speakers.

If you use very sensitive speakers, let's say 95db/2.83v/1meter, since noise is mostly a constant in the amp, and sensitive speakers need much less output, in this case 10-12db less power than a typical speaker, it is possible that a better noise spec could make an audible difference in quiet passages. I have to admit I doubt it even at -57db, but I'd bet $100 that at -75db it was never more audible than -97db. Would I rather own the -97db@1W amp? Absolutely. Is such a low noise spec audible? I really doubt it, especially with more typical speakers.

Thanks for that. So measurements at full output are similar in a way to measure output wattage at 1khz as opposed to full range. At least it would seem like it.

 

[Swerd]

Thanks for that explanation. I see how SNR relative to 1 watt vs. SNR relative to full rated power can be different values. Because they both are called 'SNR' it might seem like apples compared to apples. It's not quite apples vs. oranges, but more like different varieties of apples.

Noise, unlike distortion, is mostly a constant value regardless of output, and most absolute measurements I've seen are in microvolts, and IMO are best plotted in a microvolt scale across a frequency spectrum. That's cumbersome, so broad-spectrum unweighted SNRs are the convenient figure of merit.

Can you post an example of such a plot?

 

[PENG]

That's what I'm wondering.


Thanks for that. So measurements at full output are similar in a way to measure output wattage at 1khz as opposed to full range. At least it would seem like it.

If you have one, you can calculate the other. The calculated value may not be 100% accurate but should be good enough for apple to apple comparison.

 

[PENG]

I also prefer JA's bench tests, but usually ignore their subjective review part. As good as Kal Rubinson, he would still say things (quoted in bold below) in that review.

"....That's where I discovered that my new hero amp wasn't quite perfect. Oh, its power and resolution were still not to be faulted, but through a pair of Monitor Audio Silver 8 speakers, the sound was somewhat hard and thin.". He went on to say: "Again, I would describe it as a loss of warmth and resonance in the fundamentals of their voices. Unfortunately for the AHB2, this loss pervaded the sound of whatever recording I played. I wrote it off as an example of an amp-speaker mismatch....."

There is no end to this if you believe in individual amp's sound signature things, that is further complicated with the need to match with speakers, and by extension, presumable also interconnects, speaker cables, and every other device in the signal path, aside from the regular stuff such as input/output impedance, sensitivity, output levels etc.?

I wonder what would Mr. Siau say about "amp-speaker mismatch", in this case ABH2 vs MA Silver 8. I think we can reasonably guess his response based on:

https://benchmarkmedia.com/products/benchmark-ahb2-power-amplifier

"DIFFICULT SPEAKER LOADS ARE HANDLED WITH EASE"

 

[Irvrobinson]

If you have one, you can calculate the other. The calculated value may not be 100% accurate but should be good enough for apple to apple comparison.

The rated power A-weighted specifications are so suspect that I probably wouldn't believe the calculation, but if you start with a one watt measurement and calculated the rated power number I'd believe that.