Hardware suggestions for low latency.

Subject: Hardware suggestions for low latency. Sun May 29, 2011 9:22 am

Hi,

Next week I will be building a custom box dedicated to reaper + remix os. My budget for hardware excluding screen or case is approx $1000. I'm hoping to achieve as low latency as I can with this budget. Any suggestions for hardware?

Oh, I am aware that interface/sound card has a large effect on this, and at the moment my interface is a phonic helix 18 universal through firewire and ffado. I may upgrade interface in future, however i've had it running at latency of 5ms under vanilla ubuntu + rt kernel on crappy old laptop, so I figure it can be improved a little with a better machine + os. Also, although pre-amps are not amazing, it's mainly line-level devices + condensor mics I'm using so I don't need a huge amount of gain, plus the interface samples 24bit @ 96khz, is also a mixer, and was quite cheap.

Admin Posts : 60 Join date : 2011-05-28

muncheeez wrote:: Hi,

Next week I will be building a custom box dedicated to reaper + remix os. My budget for hardware excluding screen or case is approx $1000. I'm hoping to achieve as low latency as I can with this budget. Any suggestions for hardware?

Oh, I am aware that interface/sound card has a large effect on this, and at the moment my interface is a phonic helix 18 universal through firewire and ffado. I may upgrade interface in future, however i've had it running at latency of 5ms under vanilla ubuntu + rt kernel on crappy old laptop, so I figure it can be improved a little with a better machine + os. Also, although pre-amps are not amazing, it's mainly line-level devices + condensor mics I'm using so I don't need a huge amount of gain, plus the interface samples 24bit @ 96khz, is also a mixer, and was quite cheap.

With wineasio the latency doesn't depend on audio card - at least the JACK shows so. For 48000 Hz sample rate it should be:
128 - 2.6/5.3 Msec
256 - 5.3/10 Msec
512 - 10/21 Msec

But the better audio card can work with a smaller buffer size.

And the real latency can differ from shown by Jack.

Subject: More info? Sun May 29, 2011 3:47 pm

any chance you could point me in the direction of some good info on this?

How could one find out real latency?

How can you setup for very small buffer sizes?

Is latency of say 5ms including some vsts acheivable in practise with high end machine+reaper+wineasio+wine+jack+ffado ?

Sorry to swamp with so many questions, if you are finding it annoying I'd very much appreciate a suggestion of some good literature on this subject, it would be nice to understand the process...

Admin Posts : 60 Join date : 2011-05-28

muncheeez wrote:: any chance you could point me in the direction of some good info on this?

How could one find out real latency?.

To mesure the real latency you can record the output of your card. Connect the output to input, play a track and record the input to another track. In Reaper you should set the input for "no latency compensation".

muncheeez wrote:: How can you setup for very small buffer sizes?

Just play a session with the amount of tracks and plugins you want to use with different setups of the buffer size. The same thing for the sample rate.

muncheeez wrote:: Is latency of say 5ms including some vsts acheivable in practise with high end machine+reapetonr+wineasio+wine+jack+ffado ?

128/96000 setup will give you 1.3 Msec - if your card can work stable with it. In my practice I succesfully used 64/96000 on Mia Echo MIDI PCI card - so the latency was less than 1 Msec. Funny - it's a cheap card showing a very good perfomance.
And keep in mind: for more tracks and plugins you need a bigger buffer size (or a smaller sample rate). Also some plugins need more resources, some - less.

muncheeez wrote:: Sorry to swamp with so many questions, if you are finding it annoying I'd very much appreciate a suggestion of some good literature on this subject, it would be nice to understand the process...

There's no more theory about it. I tnink you can find some tests in web to know wich audio card gets less latencies. Anyway, to setup your own one you have to experiment.

Posts : 9 Join date : 2011-06-04

muncheez, I doubt it's gonna get much better than that and I doubt you could get that kind of action in Winblows - OSX maybe, Linux definitely.

I went looking for something that I'd read about latency to help you out, couldn't find it, but found this instead.

It's got some obvious Windows connotations but the majority of the info is still relevent. I'm not too fond of the 'txt0r' style that it's written in mind you, e.g. ur=your, etc, but don't let my 'speling-nazi' opinions sway you... Smile

I don't think you'd get much better with analogue stuff either, mate Smile

Posts : 9 Join date : 2011-06-04

P.S. If you open Package Manager, click on Sections, scroll down to Multimedia (universe) there's an app you might want to try called jdelay that you can install

Quote :: Jdelay is a simple JACK application that you can use to measure the
latency of your sound card. It uses a phase measurements on a set of
tones to measure the delay from the output to the input. Accuracy is
about 1/1000 of a sample.

Admin Posts : 60 Join date : 2011-05-28

[quote="Schprocket"]there's an app you might want to try called jdelay that you can install
[quote]

Jdelay shows the frames/period value - the same that you can see in Qjackctl. To know the latency in msec's you have to calculate:
((frames/period) x 1000) / Sample rate x (periods/buffer)