Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Proper Processing of DSD to PCM Conversion using FIRs (Read 4068 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Proper Processing of DSD to PCM Conversion using FIRs

Hello Everyone,

For awhile now, I've been using foobar2000 to separate SACD ISOs into separate 24/176 flac files. I'm not here to discuss the potential loss of quality upon converting from DSD to PCM, I'm simply looking for the best way to do it. In foobar, there are a number of settings for conversion that come built into the DSD plugin. These are:

  • Multistage (Floating point, Fixed point, Double Precision)
  • Direct 30khz LF (Fixed point, Double precision)
  • Installable FIR (Fixed point, Double precision)


What I have been using with some success, and what sounds best to my ears, are the installable FIRs at different frequency cutoffs. Each FIR file (30,40,50,60khz) applies a high-pass filter on the otherwise very noisy DSD file. Each DSD file has a different amount of this ultrasonic noise distortion, so different FIRs are best for different recordings. What I would like, is to have more fine grained control over the frequency cutoff of these files, to have FIRs that are 31,32,33khz, etc. This way, I could best customize the high pass filter to the file.

Does anyone know where I could find these, or how I could produce them?

Regards
Kogam4

Proper Processing of DSD to PCM Conversion using FIRs

Reply #1 –
When you say noisy DSD file, do you actually hear that noise? At what frequency does that noise occur? And how do you measure it?
Error 404; signature server not available.

Proper Processing of DSD to PCM Conversion using FIRs

Reply #2 –
Quote from: hlloyge on
When you say noisy DSD file, do you actually hear that noise? At what frequency does that noise occur? And how do you measure it?


Yes, the noise is very distinctive. It sounds like scratchiness in the recording, but it is simply ultrasonic noise that you can hear distorting the waveform. If you cut off the frequency range around 30-40khz, it eliminates most of the noise. I measure it with my ears, I suppose. I can either hear it or I cannot. SACD players apply custom low-pass filters when they play the file back, to get rid of the noise on the actual recording.