Question about MIDI latency, etc.

[LR Weizel]

I'm looking at getting a new USB audio interface for my laptop, mainly for recording guitar and lining in keys. However I also use MIDI to connect up to soundfonts and VSTs on my PC.

 

I'm wondering if I get an Audio interface with MIDI in it, will that improve the latency a lot? Or if I continue to use the cheap MIDI/USB cable I have, but get a new audio interface, that'll improve it pretty much just as much?

 

I'm looking at the Tascam US122 and the Art USB Dual Pre at the moment but I'm open to other suggestions.

[Mediterranean]

That's a good technical question. But I'd be surprised if today's audio/MIDI interfaces didn't provide low-latency MIDI. Plus you've got the huge advantage of having a single USB cable providing both audio and MIDI transmissions to and from your computer [i.e, you'll free one USB port if your machine has more than one].

 

I took a quick look at an Edirol interface and they're now using something called FPT (Fast Processing Transmission) technology for low-latency MIDI.

[LR Weizel]

What inexpensive audio interface would you recommend? I'm looking at the 60-120$ mark.

[Mediterranean]

You're using a laptop. The one I personally use is a PCI card [for desktops] and obsolete. So I wouldn't recommend it for those two reasons.

 

Since I never used a USB interface, I can't recommend one for you, although the one you mentioned [Tascam] appears to be the cheapest of its kind out there. The other one [Art] does not have MIDI ports.

 

I am sure somebody that uses a USB audio/MIDI interface here will chime in to share what they think about it with you. And if you're lucky, they may even be using the same one you mentioned. Be patient:)

[Yoozer]

Latency is an audio problem, not a MIDI problem. Once you use ASIO drivers it doesn't matter where the MIDI comes from.

 

Yamaha Audiogram 3 is pretty cheap, too.

[Mediterranean]

Latency is an audio problem, not a MIDI problem. Once you use ASIO drivers it doesn't matter where the MIDI comes from. Yamaha Audiogram 3 is pretty cheap, too.

 

I read on the manual of the same interface you mentioned that there can be a delay when playing software synthesizers via a MIDI keyboard [though the culprit would more likely be the computer system/its configuration/specs/performance/etc rather than the interface]. Or would it be MIDI-to-audio delay caused by the interface?

 

I also looked at the interface's specs and it doesn't have MIDI ports. It is also USB 1.1

 

How old is your laptop, LR Weizel? If it's new, don't forget to read the specs of the interface you'll be buying to make sure it's USB 2.0.

 

P.S: how's your child, Yoozer?

[Yoozer]

Or would it be MIDI-to-audio delay caused by the interface?

 

Here's how I understand it, simplified, and probably wrong:

 

When Windows wants to play back a music file, it does not address the soundcard directly; because that means writing into the memory of that card, directly. Writing into that memory while other programs (say, a browser with Youtube opened up) need to do the same means problems - unless you have some kind of a software mixer. This has to be set up and the incoming streams have to be handled correctly, and that's all not a problem when you're only playing back a "dumb" audio stream. You can quickly copy part of an mp3 in memory, copy part of a Youtube video's audio in memory, multiply 'm with their respective volumes, and send the summed result to the soundcard.

 

This is not the case with virtual instruments, since you can't predict what they do.

 

Because you -have- to predict that, you need a buffer; the software detects that you're playing a key, it quickly renders a buffer of say, 1024 samples (during which you don't hear anything; this is the latency) and when those are prepared, your soundcard starts reading them. The ASIO drivers (or CoreAudio on OS X) allow direct access to the hardware for this, which means lower latencies; since added to the time of the sampling is the mixing, and perhaps other stuff that needs to be done.

 

When the buffer is not filled in time, you get gaps, which we perceive as drop-outs or crackling; there's simply no audio that's rendered in time put in place.

 

MIDI moves at the speed of 33.6k modems at max; plain notes will arrive in time because MIDI's maximum speed is limited by the type of cable used. With USB you send the note information virtually immediately, so any audible delay is to blame on the soundcard; wrong buffer settings, or just no ASIO drivers.

 

I also looked at the interface's specs and it doesn't have MIDI ports. It is also USB 1.1

Good catch, in that case I'd also go for an USB 2.0 interface.

 

My daughter's doing fine, thanks for asking! She's going to be 6 months old in November already