The Border Patrol DAC - Maybe linearity in a DAC is bad ... Spitballing


Hi Everyone,
I've been thinking about a few things related to DAC's and how they behave and how we hear. Also thinking about a couple of audiophile comparisons I've heard and how we interpret what we hear.

Let's talk about this simple measurement called linearity.

In a DAC what we mean is that as the magnitude changes the output changes the same amount. That is, if the signal says "3 dB softer" you want to get exactly 3 dB softer output on the jacks.

And with modern, top tier DACs this is usually really good until around -90 dB where noise becomes the limiting factor.

For a long time I felt that a DAC which allowed me to hear the decay of a note, so that it fades instead of stops suddenly was the mark of a truly excellent sounding DAC.

I'm wondering if what I'm actually hearing is compression? Lack of linearity.

The reason I bring this up is that I was reading a long article about the complexities of reviewing a DAC from Border Patrol. One of the main failings, from measurements, is that it is really not linear at all. Sounds don't get softer fast enough. And ... low and behold, Herb Reichert actually makes many comments about how much more he can hear with this DAC than with others.

I'm going to link to a critique of the "scandal" so you all can get a better look:


https://parttimeaudiophile.com/2019/01/06/border-patrol-dac-revisited-audio-fur/


Also, take a look at the linearity charts in the original review. Honestly, awful. Not up to what we expect in state of the art DACs today, but ....


https://www.stereophile.com/content/borderpatrol-digital-analogue-converter-se-measurements

What do you all think? Do we need a compression feature in DACs so we can hear more details? That would make more sense to me than a lot of the current fad in having multiple filter types.

Best,
E

erik_squires

Showing 2 responses by whart

I don’t know how to reconcile the competing views among the reviewers, including those writing for Stereophile, other than to listen for yourself. You could, I suppose, write all of this off as just another example of the divide between the subjective and objective schools of audio. Doesn’t this assume that measurements showing no departure from the input signal mean ’more accurate’ and (here’s the rub in my estimation) that ’more accurate’ measurements invariably mean a more convincing reproduction of a musical event?
I’m not so sure you can always make that leap. Music is complex. Accuracy to a series of test signals tells me something but it doesn’t tell me everything. Accuracy to the master recording? Leaving aside the colorations introduced in the recording chain, what’s been done to the master to make it sound ’good’?
Accurate to the live event? Where are you sitting? How good is your sonic memory?
I think, for me, the easiest way to make judgements about reproduced sound is to ask whether it sounds real. Does a piano sound like a real piano? Very few recordings of piano sound convincing to me, convey the gravitas of the lower registers and the air around the upper registers with the bite of the attack and the gradually diminishing envelope of harmonic decay.
Subjective preference? I think some people like to hear all the detail. My preference would probably go the other way, toward sins of omission, since I often find analytical systems fatiguing. But, those are conclusions, aren’t they? One person’s "analytical" is another’s "fully detailed and revealing."
Perhaps, rather than reaching conclusions, the reviewer's job is to report what they heard, without all the gloss about hot sauce and fur. One of the most interesting things about that whole dog fight was Atkinson’s characterization of his measurements as an "opinion."[1]
Full disclosure: I bought a Border Patrol and like how it sounds. I’m basically an analog guy in a digital world. I find the biggest variable to be the difference in recording quality and mastering. That’s been a long standing issue for me in vinyl-land, and as I have only recently started to play with digital in my main system (which is far more weighted toward vinyl playback in terms of expense), I’ve been sorting through various masterings of the same recording in digital formats, mainly Redbook. There are profound differences there, which I guess should be no surprise, but I’m new at this digital thing.
Will I go all spendy on a DAC at some point? Maybe. Does the BP sound like real music to me? I’ve been pretty pleased with what I hear on some recordings, despite many years of ambivalence toward things digital....
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[1]"In our review, the DAC SE impressed Herb Reichert for delivering "refined, human-sounding musical pleasures," but didn’t do well on the test bench. (In particular, I criticized BorderPatrol’s use of what I felt was an "underperforming" chip.) Given this conflict, I felt a third opinion was called for...".

I was told how superior digital was when it was introduced. It sounded terrible to me. It’s only been in the last few years that I’ve heard material played on digital systems that provided a convincing illusion of musical reality.
The numbers, aside from questioning whether they are ’testing the right thing,’ also don’t reflect what gear sounds like in actuality, playing music. I remember hearing Spectral stuff back in the day- very precise, accurate, etc. (I owned Crosby modded Quad 63s at the time that confederation of West Coast audiophiles was using and modding such gear). To me, it sounded unnaturally precise- too precise if there can be such a thing. Real instruments don’t sound like that to my ears.
I know that puts us into a relativistic universe. I don’t rely on the opinions of others, no matter how credible. I’ve got to hear it for myself, preferably on my system, with a diverse assortment of material (still, in my estimation, the biggest bugaboo in this game- the source material often varies considerably in sonics, even different iterations or masterings of the same recording). I prefer to evaluate equipment using ’regular’ recordings, not audiophile spectaculars since I don’t usually listen to audiophile records as part of my musical diet.
One other factor- not sure how much it is taken into account when people listen at shows or in similar environments- how much ambient noise is affecting what you are hearing. I don’t tend to listen at LOUD levels, preferring to get as much musical information as I can at modest dB. To do that, you not only have to work with the noise floor of the system, but the surrounding noise of the listening environment. It’s pretty instructive to take a dB meter into your room and see just how noisy it is--
I don’t think you need ’golden ears’ to hear these differences. You do need access to the equipment, though, and often, that’s not in environments that are optimized for critical listening....