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DSP for Linux?

Shadrach

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#1
I'm a bit out of touch with the advances in audio technology; probably a lot of other stuff as well.:p
My listening space is a nightmare, I've got nodes where normal people have freckles:rolleyes:
My speakers are totally unsuited to the room they play in and messing about with bass traps and diffuseres isn't an option.
I've been thinking about trying out some correction software but most of the idiot proof applications are for Microsoft machines.
Has anyone used and found satisfactory a Linux application.
I'm ideally looking for somethinng that will work with Ubuntu 11.04 running on a 1.5GHz processor with 512 of RAM; I may be asking for a bit more than the hardware can cope with.
Otherwise, something for Puppy Linux Xenial, with 4 GB of RAM and a dual core processor..
 

pierre

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#5
It performs very well (performance wise it works well on a raspberry pi with 2 channels 48khz). You will need another software to generate the filters. REW can do that for you too.
 
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Daverz

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#8
Someone has already mentioned the Brutefir convolution engine for applying FIR filters.

DRC-FIR will generate digital room correction filters based on an impulse response exported from REW. This is in the Ubuntu repositories (package name "drc").
 

Shadrach

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#11
512 RAM??? This is 2019 not 1999 LOL
Yup, it's old.:p
I tend to keep stuff that works. A lot of the modern stuff while doing everything apart from make the tea seems very impressive, some of the old kit that just concentrates on one job seems to last longer. Mobile phones being one of my favorite examples.
 

Krunok

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#12
Someone has already mentioned the Brutefir convolution engine for applying FIR filters.

DRC-FIR will generate digital room correction filters based on an impulse response exported from REW. This is in the Ubuntu repositories (package name "drc").
DRC-FIR indeed generates very good FIR filters assuming you did a good measurement job with REW. This is of course true for all automated EQ tools but it is even more so true for DRC-FIR as it uses a single sweep measurement per channel.
DRC-FIR is now also available as part of Brute_FIR plugin for Volumio.

https://github.com/balbuze/volumio-plugins/tree/master/plugins/audio_interface/brutefir3

BruteFIR Volumio plugin with DRC-FIR support also includes SOX tool to convert impulse response exported in wav format from REW to pcm format which is used by DRC-FIR.

BruteFIR Volumio plugin also contains sweep files necessary to do measurements in REW.
 
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JohnPM

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#13
BruteFIR Volumio plugin also contains sweep files necessary to do measurements in REW.
If using REW for measurement the sweep files should be saved from the same REW version doing the measuring. There have been some small changes to the sweep generation through the V5.20 beta releases.
 

Krunok

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#14
If using REW for measurement the sweep files should be saved from the same REW version doing the measuring. There have been some small changes to the sweep generation through the V5.20 beta releases.
Uf, yes, thank you John - I forgot about that!

I will check with developer but I think sweep files with timing ref signal in current plugin version are generated with REW 5.19 Beta 8. I will see that they are updated with ver 5.20.
 

Daverz

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#15
If using REW for measurement the sweep files should be saved from the same REW version doing the measuring. There have been some small changes to the sweep generation through the V5.20 beta releases.
Thanks for pointing that out. I've been playing back the same generated sweep files on my LMS server for a while and didn't think of this as an issue.
 

JohnPM

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#16
I made some test measurements, the results are quite different at the lowest and highest frequencies (rolled off prematurely if using a V5.19 file) so I have added a sweep file version check for the next build with a message to update to a file from the current version if an older file is loaded.
 

Sal1950

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#17
Yup, it's old.:p
I tend to keep stuff that works. A lot of the modern stuff while doing everything apart from make the tea seems very impressive, some of the old kit that just concentrates on one job seems to last longer. Mobile phones being one of my favorite examples.
I only intended a small tease, no offensive meant.
I've run Linux almost exclusively here for near 20 years starting with Mandrake in 2000 and later working for 8 years bringing PCLinuxOS to life.
I completely agree on the planned obsolescence of modern gear.
My only serious concern was looking to run room correction in real time on such minimal hardware.

If using REW for measurement the sweep files should be saved from the same REW version doing the measuring. There have been some small changes to the sweep generation through the V5.20 beta releases.
A huge thanks again John for all the work you put into REW!!!
 
Joined
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#18
512 RAM??? This is 2019 not 1999 LOL
Ha Ha. Well, guess what. Back in 1999 (or thereabouts - definitely before Sept 2001 since that's when we moved into a different house) I was actually running BruteFIR on a <1GHz system with quite probably 8 megs of ram or something similar (maybe 16 by that point? not sure). A 3-way system using 64k tap filters was entirely feasible on this system, as long as you could accept a partition size of at least (I think) 8k taps. I was so psyched when I upgraded from a PIII to a 1GHz Athlon in my BruteFIR box (although that was later) - I think this was the first system I ran DRC filters on rather than just xovers. Output via an M-Audio Delta 66 soundcard, eventually upgraded to a Delta 1010.

Ah, memories. I'd definitely be interested in a comparison of the floating point performance of a RPi3 vs a 1GHZ Athlon....
 
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Krunok

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#19
I made some test measurements, the results are quite different at the lowest and highest frequencies (rolled off prematurely if using a V5.19 file) so I have added a sweep file version check for the next build with a message to update to a file from the current version if an older file is loaded.
I created a measurement sweep file with version 5.20 Beta7 which contains timing reference signal in left channel and sweep in right channel but when I choose playback from file, select that file and select right channel to import I'm getting message that timing reference is missing. Isn't the scenario where timing reference signal is not in the same channel as sweep not supported anymore or this is a bug?
 
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