Metro as a DSP

[twaboom]

Hi;

I'm trying to use Metro as a DSP with my Imic...it almost works but the latency is just a bit much for live performance. I found this in an old post...which seems to explain the problem.

Note that Software-Audio-Thru has some limitations. It delays by at least 1 audio-packet-size. It will only work well on devices that have a unified callback (no iMic) and the audio input packet-size must equal the audio output packet-size. A unified callback means that the driver calls the application once for both audio input and audio output. This is the case for most audio drivers and all ASIO drivers.

Does this mean a different interface, say a Griffin Powerwave or Ediol UA-20 would eliminate the delay?

Tim

[Jerm]

The delay cannot be totally eliminated. It will always be at least audio-packet-size / sample-rate seconds. So if the packet-size is small you can make the delay very small. 256/44100 is pretty usable.

Now as far as the interface goes, USB is not the best but as long as they device has its own driver that unifies input and output then it should work. The iMic does not. As far as the others you mention I do not know. You could contact the manufacturers and see. I would think the edirol would have its own driver.

[twaboom]

Thanks again for your help! Here' part of the Edirol UA-20 description.

Low latency with Direct Monitoring function

Direct Monitoring function allows for low latency performance while recording.

ASIO 2.0 (Win/Mac), MME, WDM drivers and Sound Manager (Mac) compatibility

Create with any music software program for Mac or PC. It’s compatible with any audio production software and optimized for ASIO or WDM compatible music software for your music creation.

This should work, right?

One other concern. I have Metro installed on my Laptop hard drive and also an external HD that I boot off of when I'm at home. When I'm performing I just use the laptop. When I'm at home I use the laptop but boot off the HD. Occasionaly when starting Metro (so far, only after booting with the ext HD) I'll get the password screen and have to go through the unlock process. That's not a big deal at home...but I'm concerned that it may happen while I'm on the road and not connected on line. Will I always have the option to do the "I promise" thing?...If so I guess that's OK...It just makes me nervous! Would deleting one of the copies prevent this? Is there a speed difference if you run Metro off the boot disc (that and the fact that I like to have a backup copy is why I have it on both drives)?

Tim

[Jerm]

Here' part of the Edirol UA-20 description.Low latency with Direct Monitoring function . Direct Monitoring function allows for low latency performance while recording. ASIO 2.0 (Win/Mac), MME, WDM drivers and Sound Manager (Mac) compatibility....This should work, right?

Well this sounds like it is quite outdated as it refers to OS 9 only. That is not enough info to know if audio-thru will work or not.

Will I always have the option to do the "I promise" thing?...If so I guess that's OK...It just makes me nervous! Would deleting one of the copies prevent this? Is there a speed difference if you run Metro off the boot disc (that and the fact that I like to have a backup copy is why I have it on both drives)?

Yes you always have the option of typing the "Promise" phrase. Metro will only install on a single non-removable hard drive. If you want to run from different drives without affecting the installation you will need two computers. There should not be much difference if you run Metro from the boot disk or not. A more important consideration would be the speed of the drives.