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Are all DACs the same - an investigation

Nessuno

Member
Annoying distortion

Annoying distortion

With P3ESRs at normal listening level (about 80dB) and light rumors from the street outside, A is barely perceptible, B definitely. Both annoying. Maybe with richer musical content they could become unaudible, but then it depends on the music:

I think with slow tempi on solo cello, viola or harpsichord the distortion would become even more evident than with single tones, without making the instruments more musical than live: not my idea of musicality anyway.
 

Batears

New member
Commercial printers

Commercial printers

Those printers shown in the the above link are very small, look at the red tool boxes beside each machine and check the actual cubic work area inside the machine.
I have just finished building a small printer from scratch, rather than a kit, and I'm not convinced that it is possible produce the article mentioned in 3 seconds

Printers no matter how lightly built have inertia and whether the print head or the table moves, they both have weight, and to zoom around at the speeds suggested in the link takes some believing. I would have liked to have seen a video as well as the story of the above in action.

There is not much choice in the plastic filament used, usually a soft thermoplastic with very little strength. Intricate parts that can be produced on 3d printers are amazing but they take time so printers are really only good for development parts.
OK,
I see, those printers in the link have nothing to do with printing underwear, they are just commercially produced printers.
 

royals1871

New member
Any memorable ones?

Any memorable ones?

Some food for thought:

It seems that some audiophiles are OK with, or perhaps even actively enjoy, the gross distortion reported here.

Yet, almost universally, audiophiles refuse to accept the notion of lossy data-rate reduction.

But a simple difference-test will demonstrate that unless you use exceptionally low data-rates for the codec in question, the impact on the audio will be utterly trivial in comparison to the clipping reported here and on NaAvGuy's website.

So is this not yet another demonstration of the simple fact that some people don't listen with their ears ;)

I've lost count of the number of DACs I've measured over the years. Dozens, maybe 100s. I have *never* encountered one that clips - not even when presented with +dBFS signals. But based on recent reports, it would appear that some people have forgotten - or abandoned - the most elementary rules of audio design.

Very sad, but perhaps not all that surprising.
Hi, very interested in how you measured these? Any memorable DAC's that performed well that you'd like to share?
I'd imagine it had nothing to do with the price.

Thanks very much.
 

EricW

Active member
Frame of reference

Frame of reference

Whether you think this pure-tone distortion is a significant audible issue or not depends entirely on your perspective. Played over a proper hifi system where these is the possibility to increase the loudness beyond that of a pc speaker, the effect is significantly more obvious. Do you subscribe to philosophy A or B? To my ears, this harmonic distortion sounds like, and measures like a defective, rubbing, buzzing bass/midrange unit.
On my Super HL5pluses, the distortion sounds quite obvious, and quite nasty.

I assume, however, that adding the same distortion to a musical signal would render the distortion less obvious, and would be perceived by many as an enjoyable "thickening" of the sound, the same way an electric guitar sounds better through an overdriven tube amplifier.

Even the simple fact that the distortion will create an audible difference to a properly engineered unit will lead many to think the distorted unit is better simply because they can hear a difference (this is the conditioning created by purely subjective audio reviews - I know, because I've been there myself).

To be able to say one is right, and the other wrong, one needs an objective frame of reference of some kind, or it's all just a matter of opinion.
 

A.S.

Administrator
Staff member
On my Super HL5pluses, the distortion sounds quite obvious, and quite nasty.

I assume, however, that adding the same distortion to a musical signal would render the distortion less obvious, and would be perceived by many as an enjoyable "thickening" of the sound, the same way an electric guitar sounds better through an overdriven tube amplifier.

Even the simple fact that the distortion will create an audible difference to a properly engineered unit will lead many to think the distorted unit is better simply because they can hear a difference (this is the conditioning created by purely subjective audio reviews - I know, because I've been there myself).

To be able to say one is right, and the other wrong, one needs an objective frame of reference of some kind, or it's all just a matter of opinion.
The frame of reference is, of course, sine waves?
 

szigony

Member
Nasty distortion

Nasty distortion

On my M30.1 the distortion is also quite ovbious and irritating.How can I check my DAC is free from any nasty distortion?
I have test CD wich is include some test signal reference 1kHz and 20Hz to 20kHz.

If I play this test signal through my Metrum Octave mkII then is able to show any unwanted distortion?
 

EricW

Active member
I can't believe it's this bad

I can't believe it's this bad

The frame of reference is, of course, sine waves?
Of course, understood.

But what I meant was that not one person in 100,000 is going to play a sine wave through a DAC before making a purchasing decision. (They should, obviously.)

I am still shocked that there are commercially-available products that would not pass a sine wave without distorting it. It literally would never have occurred to me that this was even possible.
 

ssfas

Well-known member
More self deception?

More self deception?

The frame of reference is, of course, sine waves?
That's really scary.
On an iMac this afternoon I thought I could hear the second harmonic fairly clearly, but it informed me more of the fact that my occasional tinnitus is not far off 2khz.
Off my macbook through my DAC via airplay and out of SHL5+ the 1kHz changes tone completely and, worse still, the imaging of the sound seems to flatten. It is really unpleasant.

The pure 1kHz signal, however, sounds excellent. A really pure tone, like a bullet in the cochlea. If my relatively expensive DAC is as bad as Miller Acoustics reports (it failed their 1kHz test), surely it should be generating audible harmonics from the pure signal, so the pure signal should sound bad and the one with added harmonics terrible. Maybe my DAC isn't as bad as I was led to believe.

Having contacted the DAC manufacturer for the first time today, I found out that I should have been doing software updates. Now done, it is something of a revelation, playing some 24/192 harpsichord (Pascal Dubreuil, The English Suites) and it is like a new machine. So today I've driven a designer to distraction and got a better DAC, which I call a win:win situation. If he publishes some signal tests I might apologise to him. But then I might not.

Whilst searching the manufacturer's forum, I read a post exclaiming how update version X+1 sounded so much better than version X, only for the postee to be told that the sole purpose of version X+1 was to improve the digital display on the unit.
 

witwald

Active member
Positively unbelievably bad DAC performance

Positively unbelievably bad DAC performance

To complete my contribution, attached is an off-screen photo of the spectral output of two DACs under brief single-tone test. The fundamental signal was 1kHz (the big peak on the left). A perfect reproducer would reproduce that 1kHz fundamental alone and there would be no evidence of any other tones on the graph. In the case of blue DAC, we can see that there is a hint of spurious tone at 3kHz - the third harmonic of the fundamental - and it peaks at a level of about -90dB below fundamental. It is just audible when the amp volume is turned up a little.

The yellow DAC produced a rich spectrum of harmonic distortion, and it was the buzzing, rasping nature of this distortion that was clearly audible. The third harmonic alone is only about -48dB, but there is plenty of distortion evidenced by the very high level contribution from 2, 3, 4, 5, 6, 7 ,8, 11, 12, 13, 14, 15, 16th harmonics. I have never seen anything like it, except when examining speaker drive units which are off-centre and rubbing*.

Yellow DAC costs about twenty times more than blue DAC. A DAC costing half that of the blue DAC (the TEAC) has audibly an even cleaner output.
It is positively unbelievable just how bad the yellow DAC is. It is just staggering that it is even for sale!! The issues of its merchantability and fitness for purpose come to mind.
 

A.S.

Administrator
Staff member
Sure fire commercial winner!

Sure fire commercial winner!

It is positively unbelievable just how bad the yellow DAC is. It is just staggering that it is even for sale!! The issues of its merchantability and fitness for purpose come to mind.
Not only for sale but an award winner too and with rave reviews!

We all know that audio reviewing is an unregulated game but the reliance on almost wholly subjective reviewing without any 'test equipment', not even a CD with some fixed pure tones has led and will continue to lead to this sort of product winning yet more awards.

Ironically, had the yellow DAC cost $100 it would probably have been dismissed as inadequate, but as it cost $8000 that somehow preconditions the reviewer (and consumer), and the rest is history.

What made me see red was the designer insisting to a speaker maker that a buzz was entirely acceptable. Incidentally, the reason I was using pure tones was to establish how loud I could turn up the amp volume control with the unknown DAC playing a fully loud CD before audible amp input clipping as we have noted here. It never occurred to me that regardless of amp setting, the DAC would pre-distort any signal passing through it, an entirely separate issue to amp overload.
 

pkwba

New member
Sure fire bussiness.

Sure fire bussiness.

Not only for sale but an award winner too and with rave reviews!

We all know that audio reviewing is an unregulated game but the reliance on almost wholly subjective reviewing without any 'test equipment', not even a CD with some fixed pure tones has led and will continue to lead to this sort of product winning yet more awards.

Ironically, had the yellow DAC cost $100 it would probably have been dismissed as inadequate, but as it cost $8000 that somehow preconditions the reviewer (and consumer), and the rest is history.

What made me see red was the designer insisting to a speaker maker that a buzz was entirely acceptable. Incidentally, the reason I was using pure tones was to establish how loud I could turn up the amp volume control with the unknown DAC playing a fully loud CD before audible amp input clipping as we have noted here. It never occurred to me that regardless of amp setting, the DAC would pre-distort any signal passing through it, an entirely separate issue to amp overload.
I remember my amusement when I heard in highly polished upmarket audio lounge the patronising statement of senior sales assistant that hiss and hum outcoming from loudspeakers hooked to very exclusive tube set was not anything important, the essential was the EUPHONY achieved by that heap. Clipping and distortion at its best, audiophiles - rejoice it greatly! :).

ATB
 

willem

Well-known member
Even Harbeth fell for it - initially

Even Harbeth fell for it - initially

That must have been a shock at Harbeth HQ. You think you have a top DAC on loan to demonstrate your superb speakers, and you discover that you have a DAC that sounds and measures far worse than a 25 pound Behringer DAC.

So even Harbeth was not sceptical enough of the audiophile industry. What chance does the ordinary consumer have?
 

acroyear

Active member
Miller site

Miller site

I recently came across a website - Miller Audio Tech
For anybody who registered with Miller, after emailing how long did it take for the automated log in reply to arrive back to you, I have waited 2 days so far, I was expecting one of those immediate auto replies. Wondering if I need to resubmit my attempt.
 
H

hendrik

Guest
A one off

A one off

The question remains is this a trend or an incident (expensive DACs with bad measurements) ?
 
Rationalism in design

Rationalism in design

Interesting thread. I would argue that measurements are neccessary but not sufficient for manufacturing of an audio product, so first A to get the device as correct as possible then B to tweak remaining possible adjustments by ear. I would certainly hope that is what all manufacturers do, but appearantly not...

In my experience, as I think the consensus is above, there are differences between DACs. I am listening as I write this to an Apogee One, not expensive and absolutely decent sound.
 
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