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Author Topic: Help with convolution  (Read 2714 times)

dean70

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Help with convolution
« on: July 10, 2012, 05:54:00 am »

I am trying to get convolution working with DRC generated filters. I am using DRC Designer to create the WAV files (1 for each type: ERB, Minimal, Normal, Soft, Strong, etc). I used REW to generate and export the Impulse response.

The sweeps below is all I can get with the filters loaded. No 4 is with a test copy of the filter wav files that has been loaded into Audacity and completely blanked to 0. Still got same weird result - what could be causing this? I have the WAV files in Float32 format, with the exception of no 5, which was converted to Signed 32 bit in Audacity.

Please help.

1.

2.

3.

4.

5.

For reference this is a sweep with no convolution or eq:

..and 1 with temporary peq filters created from rew:


This is the configuration file loaded
Code: [Select]
44100 8 8 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
D:\DRC\erb\LR-44100ERB.wav
0
0.0
0.0
D:\DRC\erb\LR-44100ERB.wav
1
1.0
1.0
D:\DRC\erb\C-44100ERB.wav
0
2.0
2.0
D:\DRC\erb\Sub-44100ERB.wav
0
3.0
3.0
D:\DRC\erb\SBLR-44100ERB.wav
0
4.0
4.0
D:\DRC\erb\SBLR-44100ERB.wav
1
5.0
5.0
D:\DRC\erb\SLR-44100ERB.wav
0
6.0
6.0
D:\DRC\erb\SLR-44100ERB.wav
1
7.0
7.0
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natehansen66

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Re: Help with convolution
« Reply #1 on: July 10, 2012, 03:16:58 pm »

Are you using the same sample rate that you created your filters with? I had the same problem with strange measured results. I had REW set at 44.1k, but MC was set to sample to 48k. New filers with the same sample rate measured as expected.
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dean70

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Re: Help with convolution
« Reply #2 on: July 10, 2012, 05:44:29 pm »

Thanks I will give that a try. I did do a quick test to upsample the generate filter WAV files in Audcity to 48k, but maybe that is not enough. I will re-run the Impulse measurements as 48k sample rate.


Does JRiver always use 48k filters? For example if I have music library in CD 44.1k, 96k and 192k hi-res and some 96k multi-channel BluRay concerts, etc - will the same 48k filter cover all these formats?
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natehansen66

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Re: Help with convolution
« Reply #3 on: July 11, 2012, 01:35:23 pm »

I believe it will play the native sample rate of your file unless you tell it to resample in the output format section of DSP studio. Your files say 44.1k so you will want to set REW to 44.1k as well. Personally I have MC resample to 48k and I have all my software set for 48k as well.
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dean70

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Re: Help with convolution
« Reply #4 on: July 11, 2012, 06:19:49 pm »

I re-ran the sweeps in REW with the sample rate set to 48k and went through the process of exporting Impulse as WAV (having run Shift IR function first in REW), selected Mono 32 bit signed, checked Normalize, and Windowed.

Ran sox to covert to 32 bit float RAW format (.PCM) and checked in Auacity that the waveforms match exactly (and the sample rate is correct). Ran the PCM files through DRC Designer to generate a stereo WAV filter file at 48k (also verified in Audacity)

Loaded the filter a> with a config file (stereo at this stage) and b> directly load the WAV filter file into Convolution, Output format was set to sample 44.1k=>48k, 48k=>48k, etc, but still got the same weird output (also verified using Pink PN generator in REW with the RTA running).

For whatever reason it is not working for me. I will try grabbing the Convolutor VST plugin and quickly try with that.

One other thing to note, as a test I went to Output format and set 44.1k=>44.1k, 48k=>44.1k (unusual config, I know) shutdown MC17, rerun without convolution enabled and was able to replicate this same scenario, so it appears there is something amis. Running on and AMD A8 setup - maybe its and AMD thing?

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