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Latency expectations

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Latency expectations

Postby James Lawford » Sun Mar 08, 2020 10:06 pm

Hi all;

Question about my latency expectations.

Using Reaper on a 2015 MacBook Air 13”, iRig Keys Pro keyboard controller, choice of Focusrite Scarlett 2i2 or RME Madiface XT.

Should say I’m running Bootcamp hence posting here!

Getting glitches at 256 samples 48Khz with both.

Using 4-5 instruments in Sampletank 3 - is it the soft synths killing the latency performance? There’s a piano with 1Gb memory usage. Looks like Reaper is using about 2Gb or memory out of 8Gb at the moment.

I’m lucky to have access to the RME through work (pro-audio distributor) and was expecting much better performance. This is limiting my ability to layer more soft instrument sounds with decent playability!

Thanks for any comment.
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Re: Latency expectations

Postby Martin Walker » Sun Mar 08, 2020 10:53 pm

Hi James,

I've recently invested in a new Fireface UC, largely because of its combination of high audio quality and almost legendary low latency performance, and for me it has worked beautifully.

I can if I wish run it on my PC at the lowest buffer size of 48 samples, which at my chosen sample rate of 44.1kHz gives me an ASIO latency of just 1.1mS.

However, I choose to run with a buffer size of 128 samples for 2.9mS ASIO latency, as this is quite 'fast' enough for me and brings my typical CPU overhead down to almost half the 48-sample value.

Unfortunately I have no experience of using a Mac with Bootcamp, so I can't comment on whether or not this might impinge on the RME driver performance - hopefully someone will be along shortly with some more specialised advice on this.

Good luck!


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Re: Latency expectations

Postby ef37a » Mon Mar 09, 2020 8:44 am

Only here out of interest, can be no help at all!

It would seem to my simple mind that if the (quite old?) machine is running another OS inside another OS it has quite a lot to do already?

Can you run LatencyMon?

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Re: Latency expectations

Postby Folderol » Mon Mar 09, 2020 9:00 am

Latency can be "fun" :crazy:
It is always more than the quoted figures (sometimes by quite a large margin), and the only way to get a truly correct result is with external hardware, comparing output to input. This hardware will of course have some latency itself, but at least that will be a known fixed value that can be compensated for.
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Re: Latency expectations

Postby IAA » Mon Mar 09, 2020 9:36 am

Are you running Windows for reaper? There are reports that the performance hit of running Windows is noticeable, none when running OSX.

How much disk space have you left, that can also impact performance on a bootcamp system.
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Re: Latency expectations

Postby CS70 » Mon Mar 09, 2020 10:07 pm

James Lawford wrote:Using Reaper on a 2015 MacBook Air 13”, iRig Keys Pro keyboard controller, choice of Focusrite Scarlett 2i2 or RME Madiface XT.

Wine?

Sorry just saw you use bootcamp. I guess you can't run ASIO for it?
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Re: Latency expectations

Postby blinddrew » Mon Mar 09, 2020 10:08 pm

Reaper is Mac too.
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Re: Latency expectations

Postby CS70 » Mon Mar 09, 2020 10:21 pm

Yeah, but he says he's using bootcamp? Which probably can support WDM to a degree but if he's using the ASIO drivers is probably via Asio4All and we know that goes..
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Re: Latency expectations

Postby James Lawford » Tue Mar 10, 2020 9:39 am

Using Bootcamp which is for all intents and purposes just windows running on Mac hardware.

So it’s Windows Reaper, RME ASIO drivers and RME Totalmix.

Think it’s the VI’s killing performance as actual audio multi-tracks and plugins seem to work well at lower latency.
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Re: Latency expectations

Postby blinddrew » Tue Mar 10, 2020 10:44 am

Sorry, my bad. As you were.
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Re: Latency expectations

Postby CS70 » Tue Mar 10, 2020 5:02 pm

James Lawford wrote:Using Bootcamp which is for all intents and purposes just windows running on Mac hardware.

Are you using ASIO drivers for your interface?
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Re: Latency expectations

Postby Pete Kaine » Tue Mar 10, 2020 6:24 pm

Are you using ASIO drivers?
What CPU is in the Laptop?
Have you run latency mon to establish if the drivers you have installed for bootcamp are any cop or not?

Sounds like it could be any or all of the above to me.
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Re: Latency expectations

Postby James Perrett » Tue Mar 10, 2020 11:12 pm

James Lawford wrote:Think it’s the VI’s killing performance as actual audio multi-tracks and plugins seem to work well at lower latency.

It is very likely that using lots of VI's will cause problems. The solution is to freeze the tracks that you aren't working on so the only active VI is the one that you are currently playing. Once you've finished playing all the parts in, you can unfreeze things although you'll probably need to then increase the buffer size.

If you are using convolution reverbs then make sure that they are working in low latency mode. It is also worth disabling wifi and unplugging the network cable while working on time critical things.
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Re: Latency expectations

Postby Pete Kaine » Wed Mar 11, 2020 5:09 pm

James Perrett wrote:It is very likely that using lots of VI's will cause problems. The solution is to freeze the tracks that you aren't working on so the only active VI is the one that you are currently playing. Once you've finished playing all the parts in, you can unfreeze things although you'll probably need to then increase the buffer size.

That's what I was thinking in regards to what CPU is in the macbook. I think it's going to be "U" series, if so, it'll explain most of it.

James Perrett wrote: It is also worth disabling wifi and unplugging the network cable while working on time critical things.

Only if he's got a DPC issue, it won't help unless there is already a problem directly related to it.
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Re: Latency expectations

Postby MOF » Wed Mar 11, 2020 5:35 pm

Bootcamp cpu issues will only occur if you’re using the Windows version of Reaper. I presume it’s the Mac version you’re using.
My old iMac needed a larger sample buffer and I tracked vocals without software monitoring, eventually I started to freeze tracks.
I think you’re going to have to freeze tracks, once they’re recorded and edited, to free up the cpu for subsequent instruments.
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