# JACK audio support for REW



## kripton (Feb 9, 2013)

Hi,
I'm using REW under Linux and am very thankful for this great software. As I use Linux mainly for Pro-Audio stuff, JACK ( --- link removed --- I'm not allowed to post a link yet --- ) is running all the time and uses the soundcard exclusively.
REW under Linux supports ALSA which makes it impossible to use it with the most Firewire audio-interfaces (like the Focusrite Saffire PRO 40 or the Edirol FA-101. The other interface I own is an Edirol UA-101 that connects via USB and can be used via ALSA then.
Another way is to use the ALSA-IO tools that ship with JACK to create a virtual ALSA-device that routes the sound to JACK but applies resampling to compensate clock-differences between two soundcards. This results in strange phase behaviour at higher frequencies as the attached picture of the loopback-test (soundcard calibration) shows.
Therefor I'd like to ask the author of REW kindly to add suport for JACK audio I/O (at least for linux, though JACK can also run under mac or win) to REW. There's a Java-library here: (--- link removed --- I'm not allowed to post a link yet ---) googlecode, project: java-audio-utils

thanks in advance :T


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## JohnM (Apr 11, 2006)

The Java Audio Utils link has been on my list of things to look at, but it has been there a long time. REW uses JavaSound, though having added ASIO support via Martin Roth's JAsioHost the code does support callback-based audio I/O nowadays, so an alternative audio interface is a possibility. Won't be soon though, I'm afraid.


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## trafalagar (Oct 26, 2013)

Hello ! 

I have just discovered REW, and i am trying to use it under linux with a Jack audio server. I couldn't find my soundcard.
I've tried to use JJack to make an interface between Jack and Java, but it seems don't work.
I'm trying JNAjack, but doesn't really work too.

Would you implement Rew with one of this two project, in order to let's linux audio user work with your fabulous software?

And once again, congratulation for this work.

Bye

Trafalagar


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## smartmic (Jan 4, 2014)

Hi together,

I recently installed REW on my Debian box which is configured as a (semi)pro audio system. Since REW's Java's sound layer has no working JACK interface via external tools, I also implemented a virtual ALSA Loopback soundcard (google for it, unfortunately I was not allowed to post links here). 
After quite some configuration fiddling, I finally have a stable, nice setup.

JACK plugs to the loopback device which has a sampling of 32bit. My USB audio interface supports 24bit whereas REW is limited to 16bit. The resampling works good and relies on libsndfile. I do not have the phenomenom as described above. The sampling frequency is set to 48k troughout all virtual and real devices and applications.

The advantage is that I can capture any signals ALSA routes to REW also in parallel at the "source" (I am using ecasound for that) with 24bit. Later, I will examine what are the differences from REW 16bit to analysing 24bit "by hand".

Thanks for creating REW, it is very impressive! Of course, as a Linux audio enthusiast, I would also welcome native Jack support on the feature list at some time in future. But I see that the priority is not high, giving the powerful possibilties of connecting JACK to ALSA's loopback device on a lower-than-application-layer.

-smartmic


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## HTFMAC (Jan 10, 2012)

How did you setup your .asoundrc and jack configuration to get the loopback device to show up in the REW prefs?


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## smartmic (Jan 4, 2014)

Unfortunately I am not allowed to post links here. This is very counterproductive. 

I have all relevant scripts and configuration files on Github Gists (.asoundrc and loop2jack), checkout the Gists there under the same username I am using here.

The loop2jack script is implemented as a post startup script in qjackctl and connects the loopback device.

My jackd config is /usr/bin/jackd -dalsa -r48000 -p1024 -n3 -D -Chw:1,1 -Phw:1,0 -zt pasuspender -- but I use qjackctl with the same settings in its GUI. 

Hope this helps! In case of questions to the files please use the Github comment, I check it more often than this forum.


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## JohnM (Apr 11, 2006)

smartmic said:


> Unfortunately I am not allowed to post links here.


You need 5 posts to post links (to reduce spam), you can make additional posts in the post padding thread.


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## lkwrnflknf4lk (May 15, 2019)

JohnM said:


> The Java Audio Utils link has been on my list of things to look at, but it has been there a long time. REW uses JavaSound, though having added ASIO support via Martin Roth's JAsioHost the code does support callback-based audio I/O nowadays, so an alternative audio interface is a possibility. Won't be soon though, I'm afraid.


wouldn't this be a solution (not a programer myself)?








GitHub - jaudiolibs/jnajack: Java bindings to JACK Audio Connection Kit


Java bindings to JACK Audio Connection Kit. Contribute to jaudiolibs/jnajack development by creating an account on GitHub.




github.com


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