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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
erik_squires OP
16,056 posts
 
I agree, that ears matter.

I do want to kind of emphasize that when I posted this thread I was using "linearity" as a very specific measure.

I don't mean to rehash all things about all measurements.

But, what if specifically, with DACs we prefer some compression at the bottom? Why not?

What if this is in fact correcting a problem in the ADC end?
kalali's avatar
kalali
1,977 posts
 
I haven’t heard the BP or BM DACs but I’m also having trouble accepting that the BM DAC is actually "removing" musical content from the original recording. Someone used the video analogy earlier and my guess is that the difference has to do with the level of "contrast" presented by these two DACs, perhaps just like the view of the same image presented by different monitors. I suspect the ear/brain just focuses on different parts of the same content depending on the relative contrast within the content. My 2 cents.
erik_squires OP
16,056 posts
 
@kalali

Don't you think these effects could be explained by compression?

Best,
E


kalali's avatar
kalali
1,977 posts
 
Erik, it could be but I’m sure someone familiar with the recording process is definitely more qualified to address that (valid) question. The more I think about it the more the concept of “contrast” especially measured as a ratio, makes sense to me and I feel it also applies to other audio components. It’s a metric that I don’t think is captured in the typical audio-centric measurements such as frequency response, etc. It’s sort of like putting more “emphasis” on certain areas of musical “texture” which may or may not be directly related to the amplitude at that frequency. Again, perhaps experts like Ralph, Roger, or Steve, etc.,  can comment as whether or not the concept even applies to audio. Interesting analogy nonetheless.
emcdade
95 posts
 
Subjectivist chiming in who bought the Border Patrol SE Dac and returned it....

Apparently I like the decay and transparency of a typical DAC because I felt the Border Patrol sucked the life right out of my system.  It was coloring the sound but definitely not to my tastes and it made me want to leave my system turned off.  Anyone who thinks DACS all sound the same just needs to plug this one in!  

I honestly don’t get the rave reviews for it but hey, everyone’s tastes are different.  I certainly would never recommend this as a blind buy for someone though.
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