Jack and base noise level

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mongrol
Established Member
Posts: 7
Joined: Fri May 01, 2015 4:23 am

Jack and base noise level

Postby mongrol » Wed Aug 15, 2018 10:29 am

Hi folks,
I've struggling with futility to get a decent DAW recording, midi sequencing external setup going. My DAW of choice has been Bitiwig1.3 but it's pretty ropey when it comes to sequencing outboard gear. I've been testing Tracktion 7 and it seems very usable however now I'm having audio issues. I generally like to stay away from Jack as I always get in a mess between that, pulseaudio and ordinary apps and I never use VST's or ITB routing anyway.

However, testing audio with Tracktion set to ALSA has really bad crackling through it which doesn't happen with Jack. So I'm happy to run with Jack for the time being. But when I enable Jack2 I get a base level hiss/whine/noise which stops the instant I disable Jack. I've checking patching and there aren't any silly things like mic's routed to output or anything. It's present on all sample rates and buffer sizes and is constant whether I'm recording, playing back or anything.

I've tested with a Behringer USB mixer and a Fasttrack Pro. Same symptoms on both.

What else can I check? Are there configs I could post to help?

namgang
Posts: 1
Joined: Fri Feb 01, 2019 11:39 am

Re: Jack and base noise level

Postby namgang » Sun Apr 21, 2019 6:34 pm

A very late response, but here we go. It might help somebody.

I hooked up my Ubuntu Studio 18.04 laptop to two synths and a Behringer mixer to be used with Jack and Ardour for MIDI and audio recording. The synths both support USB MIDI. The mixer likewise supports USB. I thought I was lucky. An all-USB setup: simple and affordable. However, there was unbearable hissing/whining that drove me crazy. Starting Jack started the noise.

Omitting a period of desperation, sweat and tears, here is how it turned out.

I bought two rather low-cost ($35) USB galvanic insulators and a MIDI-USB interface (also around $35). All of them feed on USB power. Note that none of this is required in theory. Practice, however, is different. In my case the difference had a price tag of around $100.

Then I unplugged one USB source after the other to find those that generated the most noise. I have reason to believe that there is no theory about this, you will have to examine your setup the same way.

The Behringer mixer got one of the USB insulators, the Korg KROME synth the other. My Yamaha MX88 got hooked up to the MIDI interface. (See footnote) Then I found that the mixer could not sit on the same USB hub as the rest of the stuff. I had to use two separate USB cables to the laptop.

The result is an acceptable, not perfect, noise level. Good enough for my use of Ardour.

Footnote: The KROME keyboard is completely useless. So I connect it by a plain MIDI cable from the MX 88. Without a suitable MIDI port left I had to connect the MX88 by USB to the MIDI interface.


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