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Old 25th March 2015, 03:35 AM   #461
derekr is offline derekr  Barbados
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Quote:
Originally Posted by spzzzzkt View Post
Not sure why? I was a beginner when I started this thread. The content of this thread documents a learning curve as members try to nut out what works and what doesn't. You would have been better off asking questions here.
Right, I'll take you up on that!! Could you and others with knowledge of digital filters post a list of suggested reading for beginners wishing to delve into it and perhaps try their hand at building the filters?

Assume we are... Absolute Beginners. A Basic 101 to get us up to speed. And eventually maybe even a how-to.....:-)
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Old 25th March 2015, 04:03 AM   #462
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Quote:
Originally Posted by derekr View Post
Right, I'll take you up on that!! Could you and others with knowledge of digital filters post a list of suggested reading for beginners wishing to delve into it and perhaps try their hand at building the filters?

Assume we are... Absolute Beginners. A Basic 101 to get us up to speed. And eventually maybe even a how-to.....:-)
Start with:

Michael Gerzon: Why do equalisers sound different?
A4: http://www.audiosignal.co.uk/Resourc...fferent_A4.pdf
USL: http://www.audiosignal.co.uk/Resourc...ferent_USL.pdf

If you have never heard of Gerzon I'd suggest reading his obituary from Gramaphone
Gramophone Obituary
or from the Guardian
Ambisonic Surround Sound FAQ, version 2.8: Section 26

Then take a look at Julian Dunn's
"Anti-alias and anti-image filtering: The benefits of 96kHz sampling rate formats for those who cannot hear above 20kHz."
http://www.nanophon.com/audio/antialia.pdf

Goes through the issues with 44.1kHz filters to underscore the advantages of higher sampling rates.

Last edited by spzzzzkt; 25th March 2015 at 04:08 AM.
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Old 25th March 2015, 04:56 AM   #463
glt is offline glt  United States
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Quote:
Originally Posted by PanagiotisPapadakos View Post
Additionally I guess all the information that hifiduino has gathered in his blog regarding the filters, could also be useful for this thread. Maybe you could ask permission from him to also use it here, in the first page of this thread. https://hifiduino.wordpress.com/2015...kris-r-2r-dac/
Please...
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Old 25th March 2015, 01:17 PM   #464
derekr is offline derekr  Barbados
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Quote:
Originally Posted by spzzzzkt View Post
Start with:

Michael Gerzon: Why do equalisers sound different?.....
Thanks, Paul. Appreciated. And yes, I knew of Michael Gerzon but hadn't seen that tribute.
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Old 25th March 2015, 11:07 PM   #465
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Quote:
Originally Posted by spzzzzkt View Post
Does the altered FIR2 solve this?
I measured the following filters.
1021filt_FIR2_MP.skr
A_CRaP_take_on_BH.skr
CRaPMagic_LP.skr
totalCRaP_rev2.skr

New FIR2 unfortunately is similar to Soekris FIR2. It was not like I thought FIR2 problem.

I think it's Jitter problem when the clock works at 44.1 and multiples. Could be clock speed periodically switching? With a larger buffer I could check if it is the problem. Soekris says can´t change the length of the buffer. So I can not verify if that is the problem.

But I have found that DAM1021 measures are better than other R2R DAC in to market with high prices.
So measures are not a problem. Only more improved on 48,... Now I looking for no clipping at 0 db. and a good phase and good impulse response.
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Old 26th March 2015, 03:03 AM   #466
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Oneoclock

Thank you for the hard work.
Any details about your set up? (such as psu used or modded?)
How do you conduct the measurement?
What equipment do you use?
Any data to share with us?

Please feel free to share with your ideas.

Last edited by B&W_arthur; 26th March 2015 at 03:04 AM. Reason: amenment
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Old 26th March 2015, 05:07 AM   #467
jaffar is offline jaffar  Russian Federation
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Quote:
Originally Posted by oneoclock View Post
I think it's Jitter problem when the clock works at 44.1 and multiples. Could be clock speed periodically switching? With a larger buffer I could check if it is the problem. Soekris says can´t change the length of the buffer. So I can not verify if that is the problem.
Please post a couple of J-test graphs with 44.1 and 48k signals (stock filter) where the 44.1k problem is clearly visible, so we can ask Søren to investigate the issue.

Thanks.
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Old 26th March 2015, 02:09 PM   #468
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Messing around with rePhase. Please read the following with questionmark.

Copied pos’s filter from post #1630 and generated 32 bits float mono (txt).
Added a simple PEQ -3dB constant Q8 5100Hz and generated a new file.

Compared both files in ConTEXT editor. Not one single coefficients tap where identical. As expected as 1015 taps have to be distributed to more tasks.
By the look of it we do loose accuracy with 1015 taps when giving pos’s filter more to do.
Click the image to open in full size.

Adding taps doesn’t always give result as predicted for beginners like me. Picture below show pos’s filter with the PEQ adjustment as before at 1033 and 1034 taps. It’s like rePhrase makes two different priorities for these two outputs? With my very limited knowledge I would in this case go for the one with less taps?
Click the image to open in full size.

Changing windowing from ‘hann’ to ‘blackman-harris’ with my PEQ version did have impact on ringing. Anyone know if there exists a simple prons&cons list for rePhrase’s availably windowing styles?
Click the image to open in full size.
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Old 26th March 2015, 07:47 PM   #469
ristar is offline ristar  Singapore
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I think it was mentioned earlier that rephase works better with odd taps... hence why we use 1015 instead of 1016. That may explain some of what you're uncovered?
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Old 26th March 2015, 08:19 PM   #470
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Ahh, thanks ristar. I've read there are a 1016 taps bug, but didn't realized it could be odd/even related. Makes sense when you point it out.
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