VSTs, latency, and overall performance

[DrNewcenstein]

Some years ago I got a demo of Amplitube 2 DUO LE, but never really did much with it until the other day. Basically I would just use it as any other track effect in post-production, as the latency was just too much to use it "live".

I started playing around with the settings for the ASIO drivers of my MOTU unit, and found that by dropping the latency I could actually use Amplitube "live" as a vst.

However, using it to record a track while other tracks were running is impossible, since all tracks (including the live one) are extremely choppy. Even bouncing everything else down to one stereo track doesn't offer much improvement.

Surely someone here knows how to do this without the problems? Should I drop the sample rate of both the unit and the recording session from 48kHz? how low should I go? 22?

I'd like to use it on my laptop for on-the-go recording, and then bring those tracks into my desktop for the "real" session, but I'm not sure about up-converting. I guess it wouldn't hurt since it'd be recorded as a clean track?

 

[DrNewcenstein]

Re: VSTs, latency, and overall performance

Tried it on my desktop, and I was able to record two mono rhythm tracks separately which both used Amplitube as a live vst, while playing back 24 pre-recorded tracks (solo was broken up into 9 sections/separate tracks, including harmonies), and running a Mastering plugin on the Master output track.

That at least tells me it can be done with the stuff I have. I just have to migrate all that to my laptop and try it on there (had some trobule with it last night whereby my VGA output stopped talking to my 55" TV, and I'm not interested in squinting at a 15" laptop screen 5 feet away).

The MOTU Audio Express unit I'm using only goes down to 44.1kHz, but Audition 3 keeps setting everything back to 48kHz.
Might have to rebuild the session from the ground up starting with the hardware settings first, then see what Au3 can do with it.

 

[Virtual Kevorkian]

Re: VSTs, latency, and overall performance

The issue that you're running into is that either your buffer rate is set too low for your computer to handle while getting a low enough latency to record with, and that's all down to the specs of your computer. It could very well be that your machine just doesn't have the processing power required.

44.1 and 48k won't be very different as far as CPU usage, or really sound for that matter. FWIW, you change sample rate in your DAW, not on the interface; the interface will follow suite.

 

[DrNewcenstein]

Re: VSTs, latency, and overall performance

It works! Yay me. Thanks for my help :lol:

Anyhoo, I had to bounce down the "keeper" tracks (drums, bass, solos) and then save it as a 44.1kHz stereo track, and start a new Session set to 44.1kHz, and set the MOTU Audio Express to 44.1kHz. After that, I was able to record two separate mono rhythm tracks using Amplitube as a live vst. The audio is only slightly choppy, but it's not enough to make me lose the beat.

At least now I can shlep a guitar to werk and flesh out ideas and shtuff at lunch.

 

[Jet-Jaguar]

Re: VSTs, latency, and overall performance

Amplitube 3 free is available as a free download (doesn't have all the amps and effects as the full-blown product, however.) Have you tried it instead of 2? Might work better.

 

[DrNewcenstein]

Re: VSTs, latency, and overall performance

The issue that you're running into is that either your buffer rate is set too low for your computer to handle while getting a low enough latency to record with, and that's all down to the specs of your computer. It could very well be that your machine just doesn't have the processing power required.

44.1 and 48k won't be very different as far as CPU usage, or really sound for that matter. FWIW, you change sample rate in your DAW, not on the interface; the interface will follow suite.

Oops. Didn't see this before I posted my last reply.

Oddly enough, the MOTU wasn't following the DAW's rate setting. Au3 kept crying about "the recording hardware sample rate is different than the session sample rate ermagherd!", so I had to open the control panel and set it that way.

And yeah, the laptop's a few years old: Toshiba Satellite A205 with Vista Home, Intel Dual-Core T2450 2GHz/2GHz, 4GB RAM. The primary drive is only 5400RPM as well, but the external (USB2) drive that has all the "stuff" on it is SSD.

Still, it works for what I need it to do right now.

As an experiment, I set the MOTU's sample rate to 192, 256, and 512 samples and re-recorded the same rhythm track at each setting in the 44.1kHz session. 512 is manageable, I'm sure since there's only 4 tracks (the stereo mixdown and the two mono rhythm tracks). I was able to record both left and right rhythm tracks with each one using its own instance of Amplitube (rather than pumping them into a single FX bus).


In the 48kHz session with all the separate tracks, 256 samples introduces just enough latency that I play slightly ahead of the beat to try to get Amplitube's audible output to fall on the beat (it's a skill I managed to nearly-perfect several years ago and can't get rid of), but during playback it comes out slightly ahead of the beat. Enough to blow the track.

I still get choppy playback at 512 samples, so much that I lose the beat entirely in places.

1024 is as high as it goes, and that's entirely out of the question as the latency is just ridiculous - almost a quarter of a second.

192 samples isn't too much different from 128 samples in terms of latency. Might work with that for a bit. Any improvement is an improvement.

 

[DrNewcenstein]

Re: VSTs, latency, and overall performance

Amplitube 3 free is available as a free download (doesn't have all the amps and effects as the full-blown product, however.) Have you tried it instead of 2? Might work better.

I was not aware of this, actually. Usually IK sends me emails telling me about their new $$$ products, so I ignore them :lol:

I'll see what I can see with A3. :fing2:


I have also been playing around with AcmeBarGig's Shred vst. Loads a lot faster than their other stuff (pickup replacer, BIG, and DIG amp sims), and has lots of features. Their stuff isn't bad. Can't believe they're free at that quality, though of course they do have stuff you can buy. 25 Shred add-on heads for $25 sounds like a deal.
Plus you can Frankenstein different head sections - drive, EQ, power, cab, etc.