Filter brewing for the Soekris R2R

Why don't you upload a .skr file for us to try?

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By using external x8 filter we can bypass onboard... It doesn't have to be x8, if you only have 96Khz input I think that can show some differences too. My point is to compare the default brickwall in Resampler-V with a much less aggressive one that sacrifices FR and alias suppression. Just to throw the idea out there if anyone hasn't tried. Should be like a 5-minute setup if you're using Foobar already.
 
I'm out.

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Actually you might be right again. Out of curiosity tried an ABX with everything I had in mind, and I'm not doing much better than chance, even though I thought it'd be easy in the last couple of days. I would conclude from my experience that there might be systematic confounding factors that influences our judgment on this. Heck, the live music experiences that we so trust as ground-truth are probably the most heavily biased, since concertgoing is even more social and multi-faceted. It doesn't mean that there isn't a difference, but maybe at some point we'd get more enjoyment out of training our imagination than training our equipment. Even if there's a difference, ABX might not be all powerful as we'd like to believe - there's a lot that happens during test-taking...
 
The file im using is called TNT441Lin2noDC.skr and it seemed to be stock with only linear filter changed, not sure where I found it, cant find the post again.
I found the most recent 4k tap 1021 files posted by spikestabber and you on page 170, I suppose your filter and the NOS filters will work on 1121 but some of others need 4K tap firmware.
 

TNT

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Aha - thats how you do it ;) Tuff crawd :-D

This plays music as it can be heard in real life (44,1 (maybe 48?)). I stand by that.

Never loaded it - be careful...

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Ill let you know how it sounds :)

btw is the deemphasis filter only truly active with (rare) specially flagged audio files or something like that?
If not you would expect more discussion about its influence on sound/disabling it,
There was one mention I found of someone disabling in an old post .
 
Really like that filter, super smooth compared to stock linear filter and maybe even a touch better detail retrieval at the same time, gain is noticeable lower I wonder if the extra headroom is part of that.
Best way to describe NOS filter sound would be direct but sloppy,
though that's not a surprise, I was more interested use NOS only for FIR2 but appears you cant ''mix and match''.
 
I’m interested in getting a 1% tolerance dam1021. I’ve almost designed my own R2R but for the price the only annoying thing is use of a Spartan 6 rather than something a little more modern with a little more resource (Artix7 perhaps with DDR). I’ve programmed FIR filters for Astro image convolution, matching poles to the scope psf on GPUs.

So a see questions (the filter designer doesn’t work on my iPhone)
* is the FIR/IIR filter able to implement a sinc filter/upsampling without introducing too much error? it looks like a Chebyshev filter by default? I was thinking butterworth perhaps with a bessel as options too.

* I take it that it can implement a pipeline but at a reducing pipeline rate as the rate increases?

* has anyone added a final passive RC low pass as a softer filter after the pwm switching?

* is the Firmware is closed source? I see sdk files (encrypted?) and a “makerom” dos exe (I’m on OS X/Linux) so it smells of secure boot using prehistoric unsupported tooling? So in 10 years the firmware filters can’t be updated easily when the resistor tolerances have slackened, much like the owner :D

* I was going to model the design in python/ngspice to experiment with filters. How close are the filters to matlab/octave? I could model the coefficients in a jupyter notebook if the tooling is aging.

So it’s either go down this route or DIY it (with 2-3x cost).