spike/traction/latency adjustments

[hemant]

I've been testing out the XD-2/traction2 package on an imac for the past few days and thought I would relate some findings and questions. I'd like to first mention that so far the unit has been performing error free (other than adjusting for latency), and I find that the preamps sound good to me.

The xd-2 has a fixed setting of 48K, supposedly it automatically adjusts for traction at 44.1 k...I noticed that traction/xd-2 perform better together if they are both set to 48K (can be run at lower latency). A tech at mackie confirmed this fact, so I guess I am now going to run traction exclusively at 48K. My question is, can I import a 44.1K file into traction if I'm running it at 48K...(ie importing a file from a CD)?

My next question is regarding latency correction. I'm looking for a method in traction2 to nudge a track back to the click. If there is a way to input a nudge value, would that just be the latency value from the setting tab?

Final question, what do you guys consider a normal latency for a usb1.1 device. I'm running 512Meg of ram, my utility feature on my computer tells me that I have at least 200meg of ram available when I'm running the interface and traction. If I'm usb monitoring only a single USB track with no other tracks playing back/no plugins is 10-20 ms at typical minimum latency setting?

I'm new to computer based recording so I have a lot of questions...any help would be appreciated!

[valley]

My question is, can I import a 44.1K file into traction if I'm running it at 48K...(ie importing a file from a CD)?

Yes. If you can run at 44.1 then do so (IE does working at 48 bring sufficient benefits to make it worth the slight loss in audio quality caused by bouncing between sample rates?).

If not then Tracktion will automatically handle resampling source audio files (such as ripped CD tracks) to the current sample rate.

My next question is regarding latency correction. I'm looking for a method in traction2 to nudge a track back to the click. If there is a way to input a nudge value, would that just be the latency value from the setting tab?

In what context? There are a number of different ways of dealing with latency sync, but it depends what you are trying to do.

Final question, what do you guys consider a normal latency for a usb1.1 device. I'm running 512Meg of ram, my utility feature on my computer tells me that I have at least 200meg of ram available when I'm running the interface and traction. If I'm usb monitoring only a single USB track with no other tracks playing back/no plugins is 10-20 ms at typical minimum latency setting?

It depends a little what you are doing. If you are only mixing then you can set the latency pretty high. IF you are playing VSTis live with a MIDI keyboard, you'll want something lower than 15ms at the minimum. If you are trying to add effects to external hardware (such as a guitar) whilst playing live, you'll need a really low latency (7ms or lower).

If you set the latency too low you will increase the load on your CPU and the probability of audio drop-outs. You'll probably also find that as the CPU load of an edit increases (adding effects etc) lower latency settings will become less reliable.

To put it another way, there is no real answer to yoru last question, just a collection of strategies.

[hemant]

Thanks for your answer on the 48K/44.1 question.

I'll try to clarify my latency correction question. I had set up my usb interface for direct monitor tracking so that I wouldn't be thrown by the USB latency delay. Listening back to the recorded track, it is lagging with regards to the click track...by what I assume is the time of latency. What does someone usually do at this point to align the track with their click track? I was hoping there was some feature in tracktion where you could nudge the track...say if you had set your latency on the setting tab to 30ms, can you input a track-move of 30ms to align your tracks after they are recorded.

Again my final question, I'm trying to assess the XD-2 in terms of whether it's giving me a reasonably low latency compared to other usb 1.1 devices. I'm doing tests just recording a single mono track, no plugin's, no other tracks playing...I'm basically miking an acoustic guitar. I'm wondering what kind of minimum latency people are getting with their USB devices in this situation. From what I understand, the design of the usb interface drivers also contribute to the minimum latency.Right now I seem to be getting down to about 10ms latency before I get digital pops, is that a reasonable latency for such a simple recording situation or should it be lower?

[hemant]

Since this posting I've actually received a response from Sweetwater regarding some of these questions. By the way Sweetwater has turned out to be a good mail-order experience, I was originally shipped a defective xd-2...their response was quick and well organised.

The tech from sweetwater mentioned that there is a delay compensation feature in traction for realigning tracks...a "time adjust" setting in the input properies window.

He also mentioned that for macs, you have to reset your energy saver option to highest, if it's on automatic, issues come up that look like buffer problems.

I'm looking forward to trying these suggestions in hopes of further illumination.