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
@mzkmxzv,

You hydrogen based life forms are funny. Anyone can be tricked, even those who adhere strictly to measurements. It is with long term critical listening that we appreciate the differences and distinctions. 

Quick switching (A/B/X, whatever) is nothing more than a cheap parlor trick. Even your ears would be fooled into thinking you're hearing an excellently measured piece of kit about half the time when it's not.

Sighted references are just that and no amount of back seat psychobabble will account for all the situations as there are people who can overcome the stupidity of listening tests because they do have better ears. It's statistically inevitable that they can. Do the math since you're so good at it.

Also, all of your anecdotal evidence is just that. For every story you dredge up, there are those that prove the other point of view. And please, everyone, don't let someone dictate what "cold and sterile" is for you as mzkmxzc states.

For me, it's an unemotional and dry presentation. It can be full of bass and have what most would consider a normal treble but where it fails for me is a deficit of tone, body and timbre: a threadbare presentation. It simply won't pass the test of fooling anyone in an adjoining room or even off to the side  that something live is playing. It will measure well but it will not sound right.

All the best,
Nonoise
Reichert is a very experienced listener and professional reviewer who additionally had access to the live Chesky studio and master file. He had access to both DACs and could compare directly.  It doesn’t get much better than this in terms of knowing the actual sound of the recording you are listening to. 

 He is quite adamant that he heard musical information that was present on the master file  and subsequently conveyed convincingly with the BP .  The BM was notably inferior  under these listening circumstances according to him..  he simply and honestly reported what he heard. I don’t believe for a moment there are any ‘mind games’ being played here.  

One may not like the results of his listening sessions but he is reporting what he experienced.  In this scenario one DAC was clearly found to be better than the other, in this case the better sounding DAC happened to be the BP 
 Charles
He is quite adamant that he heard musical information that was present on the master file and subsequently conveyed convincingly with the BP .

Yep, and looking at the measurements, the lack of linearity is an interesting clue, one which supports a hypothesis I have suspected before I even heard of the BP DAC:
DAC’s are too linear. Very linear DAC’s cut off faster. DAC’s with compression are more revealing, without the frequency response aberrations associated with "revealing" speakers.

I’m going to try to prove this in 2019. :)

Best,
E


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....
I had a very similar Spectral experience (Dr. Keith Johnson controlled the room) with them  driving Avalons at CES in the late 1990s. The sound quality was threadbare,  mechanical and artificial in my opinion.  About 30 minutes after this demonstration I heard in another room the exact same Avalon model speakers driven by Jeff Rowland electronics. Substantially better, natural and very emotionally involving relative to the Spectral components. Much more instrumental realism.  Those Avalons really revealed the stark sonic differences between the two brands. I wouldn't be at all surprised if the Spectral components had the superior measurements on a test bench. Hearing both there was no comparison.
Charles