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Software: Glitch free recording: Settings for EigenD / soundflower / Logic

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written by: geert

Hi Bjoern,

When pressing a lot of keys at once (like pressing flat down with your whole hand), EigenD can at times have trouble to hold up and you might hear a crackle. However, when playing musical pieces, this should never happen. EigenD dynamically increases polyphony and keeps some headroom. If you exceed that headroom by creating too many polyphonic events at once, a crackle can occur.

Best regards,

Geert

written by: Bjoern

Wed, 7 Dec 2011 09:44:27 +0000 GMT

Hello!

I am using a pico/EigenD (1.48-testing) audio output to soundflowerbed (1.5.2) and then into Logic Pro (9) (on a high end MacBook Pro). Recording audio in Logic Pro in this way sometimes gives "glitches", i.e. the audio doesn't record "cleanly" in places.

The only relevant setting seems to be the buffer, and I have set the buffer the same on all applications, but that doesn't seem to make a big difference. (In fact, a large buffer, say 512, doesn't really seem to cause noticeable delay.)

Any thoughts? Man thanks!
Bjoern


written by: john

Wed, 7 Dec 2011 10:53:47 +0000 GMT

Hi Bjoern

Apparently Soundflower is broken on Lion, as is Jack. Apple made some low level changes to the audio interface that causes them to pop and crackle. If you're interested in the technical side of it, here's the relevant report;

Soundflower issue.

There is unfortunately not much we can do about that if you are using Lion. I suspect that it will get fixed fairly shortly, it make Soundflower almost useless otherwise. You can, if you are brave, technical and have plenty of time to spare, apparently build Soundflower from source with some parameter tweaks and get it to work.

In the meantime your best solution is probably to use an audio interface that allows loopback natively. Geert reports that the Metric Halo interfaces work well for this, and you may find that your current interface does this. We don't unfortunately have a list to hand of the ones that do, any reports from members who can see if their interface does it would be greatly appreciated - if we get enough we can make a Wiki page to list them..

John


written by: john

Wed, 7 Dec 2011 10:56:38 +0000 GMT

A followup link, you might find this useful; Using Soundflower on Lion.

John


written by: geert

Wed, 7 Dec 2011 12:17:46 +0000 GMT

Just another idea, but I haven't tried it yet, another solution could be to route the built-in Apple digital output back into the digital input with an optical cable (headphone to mic). You'll probably have to create an aggregate audio device for this to work though (through Audio Midi Setup), introducing more latency, but it's worth a try.


written by: Bjoern

Wed, 7 Dec 2011 16:33:23 +0000 GMT

Thanks for comments - this is on latest Snow Leopard, not Lion!


written by: geert

Wed, 7 Dec 2011 21:05:13 +0000 GMT

@Bjoern, if you play EigenD without Logic recording, do you also hear glitches? Is it only the recorded material that glitches or is it while you're performing that the glitches occur?


written by: Bjoern

Wed, 7 Dec 2011 22:30:20 +0000 GMT

OK, I see what you're thinking!

The glitches are certainly audible while performing (i.e. monitoring audio through logic while recording). But I am not sure whether they occur just when playing back EigenD through soundflowerbed, as I haven't done that extensively. I will need to try that. As it's intermittent, it's hard to tell. Will let you know!

Bjoern


written by: Bjoern

Fri, 16 Dec 2011 20:51:27 +0000 GMT

Hello,

I get glitches even when playing back from EigenD to Built-in Output!

What could that be due to?

Thanks,
Bjoern


written by: geert

Sat, 17 Dec 2011 10:16:42 +0000 GMT

Hi Bjoern,

Can you specify the specs of your machine, the software instruments you're using, which sample rate and buffer size you used.

Thanks,

Geert


written by: Bjoern

Sat, 17 Dec 2011 16:20:28 +0000 GMT

Hi Geert,

MacBook Pro, 2.53 GHz Core 2 Duo, 8GB RAM, Snow Leopard.

EigenD 1.4.8.
Device Type: Core Audio, Sample rate 44.1kHz, Built-in Output, buffer 512.
Samplers 1 and 3.

(Though I have noticed the issue with other versions of EigenD as well.)

I did look at the eigen system usage meter as well, which doesonly got up 50%. However, when I hit lots of keys together, the usage meter hits the top, producing similar noises. So it could be a performance issue. (Obviously I am making sure few other things are running.)


written by: geert

Sat, 17 Dec 2011 20:04:32 +0000 GMT

Hi Bjoern,

When pressing a lot of keys at once (like pressing flat down with your whole hand), EigenD can at times have trouble to hold up and you might hear a crackle. However, when playing musical pieces, this should never happen. EigenD dynamically increases polyphony and keeps some headroom. If you exceed that headroom by creating too many polyphonic events at once, a crackle can occur.

Best regards,

Geert



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