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Digi Performer Experts - Unusual MIDI problem!


Laurie Z.

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Hi, folks... I guess it's my turn to ask for help. We're just pre-mixdown on the new CD and we've got a big problem in a couple of our songs. Alphajerk - I've heard you're a Performer expert - maybe you've encountered this, and we could sure use help from whoever knows about this.

 

Our setup is Mac G4, 400 mhz, running Dig Perf version 2.5 with plenty of memory.

 

Our symptoms: some midi notes from the controller keyboard are experiencing +/- 40-50 ms delay (noticeable) randomly, like a slapback. Ihappens only on songs with lots of dig audio; but here's the catch: it delays even when the song is NOT playing - even when auditioning voices using midi thru. The mouse is also jumpy as we move it around the screen, but only on these songs. Beats the heck out of us and we're on deadline...!!

 

Some recommended fixes involve the sound bites menu. We checked, and the sound bites menu is using (supposedly) almost all of the bites available, so no extras clogging up the file - we've also allotted enormous amount of RAM to the program, so we can't compress or delete any soundbites.... and we've run out of solutions...

 

Anybody ever experienced this, and can anyone think of a solution?

 

Thanks much,

 

Laurie Z.

http://www.lauriez.com

http://www.mp3.com/lauriez

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Well, I don't know how expert I am, but I've been running DP for many years. Here are some suggestions.

 

1. I'm pretty sure that DP buffers the audio even if you have audio tracks muted (it's ready for you to ummute them and begin playback immediately). So it could be related to audio clog. Have you defragmented your drive? How fast IS your hard drive? Is the audio on a separate drive from the system?

 

2. On a related note, check the size of your playback buffers. Too large is almost as bad as too small. Try some different settings and see if it goes away. I've heard the same thing said about RAM allocation (that too much can be a performance killer) but I've never experienced this or done any testing myself.

 

3. You can improve performance overall by disabling unused audio inputs. Everything that's turned on is being continually checked by the program, so shut off the ones you don't need... for mixdown, you can turn them all off.

 

4. Does it always happen in the same spot in a file, or is it random? If the former, I'd look for some kind of logjam of continuous controller information (it may be choiking your MIDI interface). If it's random, it's more likely to be related to one of the suggesstions above.

 

Those are my best guesses. Make sure you check the MOTU web site for tech notes (I've been amazed at how many times a problem I figured was 'just me' was solved in a few seconds of searching). And you might search the list archives at www.unicornation.com. but remember that this is a mail list, so take it with a grain of salt.

 

- Jim Bordner

 

This message has been edited by Guest Room Warrior on 10-18-2001 at 12:18 PM

Jim Bordner

Gravity Music

"Tunes so heavy, there

oughta be a law."

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I don't think looking in the soundbites window will help because that's where audio soundbites are located. Same with the buffers - unless you are listening back through aux tracks - your buffers affect audio, not midi. I have rarely experienced midi latency with DP. When I have, it's always been a simple problem like, cables are too loose, global controllers are still on on my midi device etc... Check for the obvious first, before you go changing buffer size, RAM, or studio set-up. Have you checked the on/off note velocity controls for the midi track? I find that often helps. If all else fails, how about re-recording the midi track as audio after you've tweaked the midi plug-ins to your satisfaction? ~nel

*

 

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Jim and Nel - thanks for the fixes - we'll try everything and see what works. I also received an email from someone not a member, but with some suggestions, which I'll post here in case they're of help to someone else.

 

BTW Jim, this is a random problem in that if the file is not running - just sitting there - and I play a series of notes, every 12th or so (seemingly random) will have this delay on it, which seemed exceptionally strange to us. The data in question is all on an external firewire hard drive which is new, was purchased specifically for this project, and has not been defragged (although my G4 hard drive has and was severely fragmented before we fixed it). Where would I find the playback buffers to make a change? I'll reduce the amount of RAM I allotted - it's a huge amount.

 

And Nel - we can re-record the midi data as an audio track, but I need to add a few more parts and it's happening as I set up to record. We may take off thru and record using local on if we have to....

 

At this point, I just want to finish the track so we can finish the album....will let you guys know what we discover.

 

Thanks much!

 

lz

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I received an email on this topic and thought I would post it and my reply to the thread...

 

In a message dated 10/18/01 9:00:24 AM, GSlyTone@aol.com writes:

 

<< I have used DP since 1988. Try this, set the view filter so you don't see

notes, velocity, and modulation. Then take a close look at patch changes,

sustain pedal on's and off's, and anything else you might not need. Delete

this data.

You don't need patch changes throughout most songs, if you have this type of

data in a track, and active sensing on a keyboard, the keyboard will search

through the entire track looking for certian types of data. That could cause

a delay when the song is not playing.

You will have to post this on the board, as I am not a member.

Groovepusher

Sly Tone >>

 

Hey Sly Tone! Thanks so much for answering my plea. This is really confounding us, since all the midi-only tunes are just fine - it's just the tunes with dig audio, and particularly the tune with the most digital audio that's the worst. Actually, I'm guessing that the controller data won't be the problem (although I know it can be troublesome), because in this particular file, there's only one or 2 midi tracks (I was about to add more and finish producing the song when we encountered the problem) but there's a lot of audio vocal data.

 

I'll check through the tracks though - and I'll post your letter, and my reply to you - maybe it will help someone else, especially if it solves the situation.

 

Thanks much!

 

lz

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laurie - I understand better now, so here's a better guess. Are you running a fair number of plugins on your audio tracks? I've found that as you get close to maximum CPU load - even with the plugs in bypass mode - everything about machine performance suffers. Even if you open another program (the Finder, Word, you name it) with a heavily-loaded DP in the background, the computer's reponse will be sluggish and hesistant.

 

This would explain why it is worse in your most audio-intensive files, and why you get the effect even when the sequence isn't playing.

 

If this is the source, you can just print you plug-in effected tracks to disk and take the plug in out of the loop.

 

- Jim Bordner

Jim Bordner

Gravity Music

"Tunes so heavy, there

oughta be a law."

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Originally posted by lauriez@lauriez.com:

...this is a random problem in that if the file is not running - just sitting there - and I play a series of notes, every 12th or so (seemingly random) will have this delay on it, which seemed exceptionally strange to us.

lz

 

 

Aahhh, the old "random 12th note with exceptionally strange delay" problem.

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Originally posted by steadyb:

Aahhh, the old "random 12th note with exceptionally strange delay" problem.

 

Thanks, Byron - you're a lotta help! ;-)

 

Will try the fixes suggested this weekend - I have a feeling that Jim is heading in the right direction with this and will post our results. Sly Tone suggested a few more things, and I'll post his letter to add to the mix.

 

Thanks to you all - and if anyone else has any ideas, please pass 'em along!

 

lz

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Originally posted by lauriez@lauriez.com:

Thanks, Byron - you're a lotta help!

 

I try.

 

Interestingly, about one out of twelve of my posts is actually helpful, although usually with exceptionally strange delay.

 

On the notes that are delayed, have you tried playing them sooner? http://www.musicplayer.com/ubb/eek.gifhttp://www.musicplayer.com/ubb/biggrin.gif

 

 

This message has been edited by steadyb on 10-19-2001 at 02:57 PM

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Originally posted by soapbox:

steadyb, have you ever thought of asking Emagic for a transfer to technical support? http://www.musicplayer.com/ubb/wink.gif

 

If I did, they'd probably transfer me to MOTU tech support, then Emagic would really have the upper hand.

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Laurie Z:

 

It is known that DP MIDI timing (non-MTS) suffers as you add audio. You can avoid this by using less audio (by bouncing down) OR why not upgrade to DP 2.61 at least so you can take advantage of MTS timing? This of course assumes you have a MOTU USB MIDI interface. This will certainly tighten your MIDI timing.

Go tell someone you love that you love them.
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Originally posted by Guest Room Warrior:

LaurieZ - How'd the weekend go?

 

- Jim Bordner

 

Hi, Jim! Thanks for asking. We were able to make it work for now - between a combination of losing almost all the midi tracks and rerecording the parts as dig audio, in combination with using some features of the MTP AV interface to re-record the parts.

 

No doubt, Aeon- I'll look into upgrading before the next album project! Unfortunately, according to MOTU's upgrade features list, this is one of the few aspects I really care about...

 

In the meantime, it looks like we'll (barely) make the deadline....see ya'll on the other side!

 

Thanks again,

 

Laurie Z.

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