Latency? issues with Firepod

[HardToExplain]

Hi all:

I've got a Firepod which I use with a Macbook core duo and Ableton Live 6. I do a lot of low-latency monitoring with FX (often on several channels at once).

I've had a problem even at relatively large sample rates (500-upwards of 1000). The audio will sound fine for several minutes, then all of a sudden silence. 3 seconds of silence, then about 5 seconds of "bit crushed" audio... the kind of sound you get when you set your buffer rate -WAY- too low. After that the audio returns to normal (for a few minutes, then REPEAT!).

If I put the buffer at over 1000 I don't seem to get this problem (still testing though), but this 20+ ms delay is a lot less usable. I need to be able to use my FX live... which involves low latency and reliability (I don't think an audience will get much of a kick out of silent/bit crush).

What can I do here? I had some latency/degraded audio problems when the unit was still under warranty, but the repair was sent back to me with a "resoldered headphone jack" even though I didn't think that was the issue (which I told Presonus at the time). I haven't used the unit much for a while, but this problem (which is likely the very same problem) persists.

-Mike

[HardToExplain]

Oh,

And of course, as I'm using a class-compliant (or should I say class-complaint!) device with OSX, I get

1) a ~12% increase in processor use when I turn the FirePod on
and
2) CPU spikes

202

... but neither of those are likely responsible for my above-mentioned problems.

In some ways the FirePod is incredible (especially for the price), and in other ways almost completely unusable.

-Mike

[itsplayed]

It sounds more like a computer issue than that of the Firepod.
Try beefing up the hard drive to a 7200 rpm model and partitioning......or you could try using an external drive.
What version of OSX are you running with?

[HardToExplain]

Hi:

I do use an external drive, but that's beside the point: I'm not even talking about recording to disk. All I'm doing is the monitoring (and yes, plenty of RAM (2GB)).

[itsplayed]

You mean playback......don't you? or are you talking about, the system is sitting idle while you monitor the signal. Either way it sounds like a transfer rate issue that I don't believe is the fault of the Firepod. How many FX are running before seeing issues?

[HardToExplain]

What I'm saying is that, besides running the ableton live program and the OS, my hard drive isn't involved in the equation (I'm neither writing to disk nor reading samples from disk).
I'm not sure what you mean by "sitting idle"... it's certainly not idle (it's doing a lot of processing). But I'm not actually touching the system, I'm playing guitar, listening to the FXed sounds through my monitors, and otherwise leaving the computer how I set it up.

The issues can occur while only monitoring 1 track with 1 FX on it (Amplitube... which is only taking up about 10% of system resources).
The problems seem to correspond to buffer settings and not to how taxed the CPU is (sometimes I run 8 separate guitar channels with an instance of Amplitube on each channel... it taxes the CPU but these audio glitches don't seem to come on any quicker than with 1 channel).

-Mike

[itsplayed]

Having shared video memory, have you tried killing off as many visual enhancements as possible?
Have you chosen the correct audio driver in Ableton?

[HardToExplain]

Of course: otherwise my guitar input wouldn't have reached the software (nor would the sound have reached my ears).

Basically there's nothing on my screen other than Ableton.

[itsplayed]

I see this as an Amplitube issue....it's probably a resource hog. How does the system perform without using Amplitube?

[HardToExplain]

Hi:
Amplitube takes less than 10% of one core (and these problems can occur with a single instance of Amplitube). I had a similar problem on my old Powerbook before I ever used amplitube, so it's probably not the culprit.

A tech guy at presonus.com's forums recommended a fix that thus far (X-ing fingers) seems to be working.

Thanks for your suggestions,
Mike

[itsplayed]

Your welcome Mike, hope it works for you....is that fix to be found on Apples website?
Presonus makes reference to it but never elaborates, no details.....must be frightened of Mac consumer uninterest in their product if a fix is involved.

[HardToExplain]

Well: all the fix really involves is a) repairing permissions b) turning off airport and c) going into audiomidi setup and setting clock source from "device" to "mac" and then back to "device."

The Presonus tech would not speculate on whether the new firewire audio drivers from Apple (due with Leopard) will fix the spiking issue. I downloaded and installed the new SDK FW kit, and the 'pod would not work at all (i had to reinstall 10.4.8 over it).

However: I see that as a good thing. The new drivers are much more stringent on sent and received data (which are responsible for the spiking). The firepod won't work with these new drivers until Presonus delivers a firmware update.

-Mike

[itsplayed]

Thanks for the update Mike, it may help others in the future. I'm sure those 'fixes' will be forthcoming. Everyone seems to be scrambling right now, playing catchup to Apples newest direction......you'll have some growing pains for a while, I'm sure.