scale relaying latency

Manuel, and all,

I've been using Scala for midi relaying, and I'm generally
thrilled with the results -- less glitchy than MIDI Relay,
with all of Scala's functionality right there.

However, I'm noticing bothersome latency between when I
push a key and when I hear a sound. Here's my setup...

controller -> midi/usb box -> scala -> softsynth

I'm wondering if the midi/usb box is part of the problem,
or if it's Scala. If the latter, I guess I could just use
a microtunable softsynth, but I'm not aware of any good
general-purpose ones that can load .scl files (if you know
of one, please pass the word along).

Anybody else using a similar setup? Comments on Scala's
relaying latency?

I've also tried...

controller (Kawai K5000S) -> midi/usb -> scala -> synth (K5KS)

...but the latency problem is at least as bad.

Thanks,

-Carl

Carl,

Can I assume that with either

>controller -> midi/usb box -> scala -> softsynth

or

>controller (Kawai K5000S) -> midi/usb -> scala -> synth (K5KS)

that if you remove scala from the equation you *don't* have latency issues?

If you only experienced problems in the first scenario, I'd definitely think it was either a softsynth (rendering) issue or a soundcard issue; however, if you are experiencing latency problems using a hardware device at the end of the chain, it is looking like scala is the problem - as long as playing in 12tet and removing scala from the chain works in the pocket.

I spent the better part of the afternoon speaking with 3 separate keyboard/software guys yesterday about latency, soft synths and DAW setups. I think I have my questions answered and am going to purchase some gear. If I get it all and have latency issues, I'm am going to be one pissed off mama...

Cheers,
Jon

--- In MakeMicroMusic@yahoogroups.com, "Jonathan M. Szanto"

/makemicromusic/topicId_4843.html#4844

> I spent the better part of the afternoon speaking with 3 separate
> keyboard/software guys yesterday about latency, soft synths and DAW
setups.
> I think I have my questions answered and am going to purchase some
gear. If
> I get it all and have latency issues, I'm am going to be one pissed
off mama...
>
> Cheers,
> Jon

***Isn't latency a bit of an issue with softsynths in general?? I
don't have any latency with Scala just playing it through a
soundcard...

J. Pehrson

Joe,

Two separate issues at work:

{you wrote...}
>***Isn't latency a bit of an issue with softsynths in general??

Yes, to a certain extent. These are applications, after all, that are calculating things on the fly, so what one is trying to do is shrink the time of computation-->making-a-sound to the smallest amount. The factors affecting a delay from pressing a key to hearing a sound (latency) are:

- CPU power (a slow CPU can't compute fast enough)
- soundcard/drivers (either the soundcard can be sluggish in passing data through, or the drivers can be old or slow and don't allow the data to move fast enough, causing a lag)
- another level of 'abstraction', in this case Scala having to assign midi in a cyclic fashion as it relays to different channels (at least I am inferring that Scala's relaying functions are a real-time version of the channel/retuning algorithm - Manuel, I'd be happy to hear just what is going on 'behind the scenes')

>I don't have any latency with Scala just playing it through a soundcard...

Well, there isn't a big lag going on with a softsynth trying to get things calculated in time to make a sound. And if you *don't* have a latency issue, consider yourself fortunate!

Cheers,
Jon

Hi Joseph,

Latency can be a problem with soft synths, particularly when it is only one of about a dozen functions you are trying to do at the same time on that poor computer. It's best to remove as much overhead as possible off of the computer if latency is a problem, perhaps a faster computer, or change over to a pipe organ where latency is measured in much more than milliseconds!!

Bonnie *:>

Joseph Pehrson <jpehrson@...> wrote:
--- In MakeMicroMusic@yahoogroups.com, "Jonathan M. Szanto"

/makemicromusic/topicId_4843.html#4844

> I spent the better part of the afternoon speaking with 3 separate
> keyboard/software guys yesterday about latency, soft synths and DAW
setups.
> I think I have my questions answered and am going to purchase some
gear. If
> I get it all and have latency issues, I'm am going to be one pissed
off mama...
>
> Cheers,
> Jon

***Isn't latency a bit of an issue with softsynths in general?? I
don't have any latency with Scala just playing it through a
soundcard...

J. Pehrson

Yahoo! Groups Sponsor

[MMM info]------------------------------------------------------
More MMM music files are at http://www.microtonal.org/music.html
------------------------------------------------------[MMM info]

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

---------------------------------
Do you Yahoo!?
Free online calendar with sync to Outlook(TM).

[Non-text portions of this message have been removed]

Jeff,

BTW, good to have your contributions again - welcome back for whatever duration!

{you wrote...}
>One of the most critical issues is not processing power but buffer size.

Good point, and good info.

>Soundcards can factor into it where its mainly an issue of the driver >writer, and the OS as well. A special driver has been developed for the >Mac taht is used by many audio software companies called ASIO which goes >for minimal latency through minimal buffering and bypassing the syste'ms >sound routines. Maybe there is something like that on the PC too

Most of the audio cards and apps support ASIO on the PC as well. There is also another driver format, WDM, that works with the latest Windows configurations, that is supposed to increase communication speed even more. The Aardvark card I'm considering supports both modes of drivers, in addition to older DX and other type drivers.

>Also, for LMSO and Scala, there will certainly be at least a 3 ms delay (1ms
>to Rx the note on, 2 ms to send the pitch bend and note on out) per note
>simply due to the speed of the MIDI serial protocol, but only when coming
>from and going to hardware. If going to a softsynth, the 2 ms delay on the
>output is eliminated, which is why softsynths can actually be faster han
>hardware synths.

I've never looked to see how much, if any, the USB 1.0 or 2.0 midi interfaces (which is what I use) have improved on the throughput of the older parallel or serial midi ports.

Man, geek talk today... :)

Cheers,
Jon

> - another level of 'abstraction', in this case Scala having to assign
midi
> in a cyclic fashion as it relays to different channels (at least I am
> inferring that Scala's relaying functions are a real-time version of the
> channel/retuning algorithm - Manuel, I'd be happy to hear just what is
> going on 'behind the scenes')

No the relaying function is much simpler than the retuning function.
It really only does a little bit, so like Jeff I also don't think it's
a major time consumer. The retuning function takes program numbers and
controller messages into account, and the relaying function not.
There's also the Windows process scheduling which can take some time.

I've had an excellent result under Linux by the way, using a MIDI
keyboard, Scala retuning and the ZynAddSubFX softsynth and I noticed
not any latency. I used the special low latency Linux kernel patch,
which people say gives much less latency than the Windows kernel.

Manuel