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Old 11th January 2017, 07:22 PM   #1351
soekris is offline soekris  Denmark
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Join Date: Jun 2009
Originally Posted by levelUP View Post
batteries should be without center tap
but the scheme become little bit complex, it's easier with 3,2V instead of 4V
Yes, floating supplies will do, just not shown like that on your earlier drawing....
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Old 23rd January 2017, 12:09 PM   #1352
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I have been asked for the TXT of the filter because people need to ecualize and use DSD. I try to explain what I've done by putting together filters made by Soekris and Paul. Hoping they not to be bothered by the use of this. Otherwise, the administrator could deletes them please.

F4 is the first that provides Soekris by default. Soekris Linear Phase, 44.1KHz. 0-19.7Khz -1dB 22.3Khz -150dB. The sound seems similar to the integrated commercial DAC. It has a large slope of attenuation and produces an impulsive response of pre- and post ringing and poor phase response at high frequencies.

F5 is "EQHQ_lpbr_b4" Linear Fase published by Paul that has an even greater slope of attenuation. But its the sweetest and most pleasant sound of all filters. It produces a much better impulse response than the F4 with less ringing and a much better phase response at high frequencies. Unlike this filter published by Paul at frequencies above 88.2 Khz, 96 Khz, which dropped from 20 Khz. approximately, I performed the calculations in Excel by decimating and calculating attenuation in the impulse response to 88.2, 96, 192 ... Khz. Etc. So the attenuation at these frequencies is close to half of the sampling frequency. I estimate that: 88.2 Khz 0-40.9 Khz + -0.00000005 dB, 45 Khz -174 dB 96.0 Khz, 0-44.5 Khz + -0.00000005 dB, 48.9 Khz -174 dB The audio pass over 40 Khz. My bat pet are happy.

F7 is a NOS filter. Although some people have commented that DAM DAC an oversampling occurs in the signal. Is not true. This DAC repeat N times the signal without any skip or switching defect in each repetition, it is easily observable on the oscilloscope that the output is a perfect NOS filter with signal identical to that of any other NOS. The NOS have qualities and defects. The impulse response is perfect there is no phase variation of the high frequencies, the percussions and attacks instruments is very natural. But also the progressive attenuation of the signal about 1 Khz. produces a dark sound.

F6 is a filter published by Paul "C128dp Linear Phase NYQUIST" is the most similar to a NOS filter, only uses 8 samples at the front and 8 samples at the back, and the weight of the samples decays very quickly. The impulsive response is perfect. It is the closest to NOS but with the quality of having a flat response to almost 19 Khz. It also has a perfect phase up to high frequencies. And it also keeps zeros every N values in the impulse response which means that it reproduces exactly the same samples as the original signal, which filters F4 and F5 do not. They are several things that I wanted and this filter make. That I like most of how the percussions sound and instruments attacks. The loudspeakers in my house are temporal aligned and have a perfect impulsive response so this filter makes a difference to F4 and F5. Very similar to F7 but with trebles. I have also done with Excel 88.2, 96 Khz and above, decimating and calculating the attenuation from the original to 44 and 48 Khz. Similar in F2 filters.
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Last edited by oneoclock; 23rd January 2017 at 12:15 PM.
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Old 23rd January 2017, 12:29 PM   #1353
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This reads better.
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Old 23rd January 2017, 02:22 PM   #1354
TNT is offline TNT  Sweden
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Have you considered a "F5" with for example the filter for Fs=96khz:

a) Keeping same steepness but start filtering from 30kHz for higher attenuation at Fs.
b) use less steep filter for same attenuation at Fs.

a) is probably the most interesting option of the two.

Bat pet still quite happy. Master even more happy?

More distortion to the people!
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