1 Topic by VasilySizov (edited by VasilySizov 2018-09-10 07:30:05)

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Topic: Buffer size of 32 samples for 96KHz is not available on UFX+

Hi! Per my understanding, I should be able to set up 32 samples buffer for my UFX+ (connected via Thunderbolt) for 96Khz. I have Z370 platform with i7 8700k on Windows 10 x64.

However, when I click on Settings in the system tray, it shows me the following Buffer Sizes in the drop down menu: 64, 128, 256, 512, 1024, 2048, 4096 for the selected sample rate of 96K.

How can I set it to 32 samples?


If I open driver settings through reaper, I notice that 32 samples are available for sample rate up to 48Khz. For 64-96Khz the lowerst buffer I can set up is 64 samples only. For the higher samples rates I can set up only 128 samples.

2 Reply by ramses (edited by ramses 2018-09-10 08:24:18)

  • ramses
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Re: Buffer size of 32 samples for 96KHz is not available on UFX+

Yes but only for 44.1/48.

It should be clear that the ASIO buffer size needs to be doubled when the amount of data to be processed doubles to prevent audio loss.

That's technically required and every vendor needs to do this.

If 96 kHz with 32 ASIO buffers would be possible then the size @44.1 could be 16.

But you will find no vendor anyway who would support such low ASIO buffer sizes because the likeliness to loose audio data would become too high and simply would lead to frustration for the users.

And remember, Windows is not a real time OS ... there are concurrent processes requiring access to CPU resources.

Under higher CPU load, even the 32 ASIO buffers can be too low, depending on the project and surrounding conditions like mainboard, system load of other processes, interrupt load of the system, maybe bad drivers etc etc ...

Therefore ... if you simply record something where latency is really no issue,  then do yourself a favour and work with higher or even maximum buffersizes.

I personally use 64 or 128 when playing in guitar using VSTI at 44.1 kHz. Then you stay with the excellent RME drivers below 10ms.
Otherwise you can easily default to higher value's.

The lower the ASIO buffersize is requires your CPU to empty more often the Buffers not to loose audio date. Thus CPU and interrupt load on your system will increase. High interrupt load can be bad for a system, because the kernel routines can not be interrupted by the process scheduler. The process needs to terminate on its "own will" before the CPU is free again to process other stuff.

The higher the sample rate the more stress you will generate for your CPU, as well,  because the driver, the DAW and all VST's that you are using, have to process the double amount of data.

So it will depend much on the capability of your system and your project, what ASIO buffer sizes will be possible for your system.

With capability I do not only mean CPU power I also mean the ability of the total system to process realtime audio data in time on an operating system which is no realtime OS.

That's the little challenge for all users be it on Apple or Windows.

Also DAW settings will influence how much load your system will get and how big the ASIO buffers need to be.

And finally how many tracks and VST'S and VST instruments you use in your project.

Sone VSTs eat so much CPU time that it's impossible to run projects at 44.1 kHz with 32 ASIO buffers. Then it can be possible that you need to use sometimes ie 512. Ozone is such a beast.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

3 Reply by VasilySizov (edited by VasilySizov 2018-09-10 09:04:19)

  • From: San Jose, CA
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Re: Buffer size of 32 samples for 96KHz is not available on UFX+

ramses,

Thanks for the detailed explanation, really appreciate that.
Yes, it makes sense, though I couldn't find direct mentioning of that in the specs, that's why was confused a little bit. For me the lowest possible latencies were a deal breaker for guitars tacking with the use of amp simps, but nowaday I switched to a hybrid approach with real amps, so it is not that critical anymore and I can live even with 512 for 96Khz (however, wanted to understand why 32 is not available).

Regarding other vendors, I've just seen that Slate has finally released their VRS-8. They claim that they support 32 samples buffers for 96Khz:
"LLN utilizes a custom hard-wired converter chipset, which reduces managed components in the audio path and allows an incredible .7 milliseconds of latency at 96K (with a 32 sample buffer)."
Not sure how far from reality it is, though.

4 Reply by ramses (edited by ramses 2018-09-10 11:05:01)

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Re: Buffer size of 32 samples for 96KHz is not available on UFX+

The higher buffersize doesn't matter in terms of latency, you will see in the DAW  that with higher sample rates the RTT will go down, regardless of the fact that ASIO buffer size double's.

You need only the higher buffers because of the more data.

In regards to Slate, as if this would be a professional reference,  this is not a company I would trust. Slate is good in marketing / "bla bla" and I will definitivly not buy from them again.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • ramses
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Re: Buffer size of 32 samples for 96KHz is not available on UFX+

Addition:

With RME I can run my 400 tracks Cubase test project with VST in each track @44.1/96 kHz and 32/64 ASIO buffers without audio loss on playback. Regardless whether using RAYDAT (PCIe) or using a two UFX+ system via USB3.

This is what counts stability and reliability.

Consider that it's possible to play through a VSTi using an ASIO buffersize of 256 @44.1 kHz which is around 10ms what the driver reports to Cubase. 128 is better because under 10ms RTT.

With higher project load and the fact that 96Khz anyway puts double load to the system you will find out that stability with 32 ASIO buffers @96 kHz with such a slate solution will be extremely challenging for your system.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

6 Reply by VasilySizov (edited by VasilySizov 2018-09-10 17:35:39)

  • From: San Jose, CA
  • Registered: 2018-09-10
  • Posts: 14

Re: Buffer size of 32 samples for 96KHz is not available on UFX+

ramses wrote:

The higher buffersize doesn't matter in terms of latency, you will see in the DAW  that with higher sample rates the RTT will go down, regardless of the fact that ASIO buffer size double's.

I believe it depends on the sample rate change, but if you double the sample rate and double the buffer, you should have better latencies, so I agree with that. As I undersand, the math is quite simpe: 44100 samples/second with 32 buffer size gives us 1000ms_in_sec * 32samples * (1s/44100samp_per_sec) gives us one way trip around ~0.73ms
for 96Khz and 64 samples we would have the following math: 1000*64*(1/96000) gives us one way trip of ~0.67ms


Slate is good in marketing / "bla bla" and I will definitivly not buy from them again.

Agree, and I am fed up with their BS, but anyway I hope it will give the market some push if the device is not bad :-)

With higher project load and the fact that 96Khz anyway puts double load to the system you will find out that stability with 32 ASIO buffers @96 kHz with such a slate solution will be extremely challenging for your system.

I don't actually think it is really needed to run large low latencies projects, but it probably depends on application. In my case it was solely about tracking guitars, when it is critical to hear your playing processed with as min latency as possible. You can even track it in a separate project with metronome to avoid stability issues/cracks&pops. But in general, I agree.