Reasonable latency only at 256 samples. Does that sound right?

[adisababbba]

Hi. I recently (about two months ago) purchased a new Scarlett 2i2 (gen 2) device.

I have the latest driver installed: Focusrite USB ASIO driver (v4.15).

The laptop I'm using is also only about 3 months old and I invested in fairly powerful hardware, so I would not experience any issues when working with audio and video programs. For audio, I am currently using Adobe Audition.

I am able to get to what seems to be very close to zero latency, but only with setting the buffer size in Audition preferences to 256 samples.

For some reason, given the hardware I have in my computer, I was sure I would get zero latency using the Scarlett 2i2 with buffer to 512 samples, but when set to 512 there is small but noticeable latency.

My computer is a new Sagar laptop

Windows 10 Home 64-Bit

i7-6700HQ

32GB RAM

500GB Samsung 850 EVO M.2 SSD

the Scarlett 2i2 is connected via USB 3.1 (gen 1)

I sent an email to Focusrite and this is their response:

Quote:

It is not possible to get zero latency through the DAW, as this is the nature of what Buffer Size is.

The Buffer Size controls how many samples the computer is allowed to process the audio before playing it to the outputs.

Samples are thus units of time, as in the Sample Rate. For example, 44.1kHz Sample Rate means the computer is using 44,100 samples of audio per second. Thus if you divide the Buffer Size by the Sample Rate that is your amount of time processing, or latency.

The Scarlett offers the "Zero Latency" feature via the Direct Monitor on the unit, which allows you to hear the live inputs via hardware based monitoring that does not travel through the computer or DAW, and thus is not affected by the Buffer Size.

I'm just wondering if it's reasonable that I would not get negligible latency at 512 samples, given the hardware I have in my setup. Can anyone please let me know what I should expect, and if I should continue taking this up with Focusrite support?

Thanks!

[SteveG_AudioMasters_]

Well, doing the sums says that with 256 as the buffer size, you'll end up with 5.8ms latency. And with 512, you'll get 11.6ms. If you can get a glitch-free performance from a Scarlett with a buffer as small as 256, then you're pretty lucky, I'd say.

The latency is dependent rather more upon the software and drivers than the hardware you use, FWIW. ASIO always out-performs older Windows drivers, but the WASAPI driver apparently does quite well. Even if you could reduce the buffer size to even lower, you've still got the problem of your signals needing to be clocked through the hardware in and back out again, so you'll never entirely eliminate latency - it's not possible.

[adisababbba]

Hi SteveG, thanks for your reply.

So what would you say the standard buffer size should be set to when recording with Audition?

If say for example I have about 24 tracks of audio (mostly midi), with some effects, and I want a vocalist to be able to hear the playback via headphones while singing, and also hear herself, but with effects applied — what would you say the common practice is regarding the sample buffer size? What sounds too low? Is 128 typically fine? Would I be safe at 64 for example?

I'm just trying to figure out if my setup is acting normal, or if there's something wrong I need to fix.

I'm using the most recent ASIO driver downloaded from Focusrite website

Thanks

[SteveG_AudioMasters_]

There's no such thing as 'too low'!

The only criterion is that when you are playing back the maximum number of tracks you need to, that you don't get cracks and pops in the playback or monitoring. If you do, then you have to increase the buffer size. In general though, below 10ms people find it increasingly difficult to detect latency directly - they can only then do it in relative terms - ie, you've got an undelayed signal in one ear, and a latency-delayed one in the other.

[adisababbba]

Hi SteveG, sorry took some time to get back.

I understand what you're saying. Just was curious to get some opinions from experienced audition users on whether what I'm experiencing with Audition when using the Scarlett 2i2 on my rig seems reasonable, or if it seems like something is wrong.

[Bob Howes]

One other thing to remember is the Direct Monitoring switch on the 2i2.  Turned on, it will route whatever you're recording direct from the 2i2 to your headphones rather that after the round trip through your computer.  The Scarlett isn't as user friendly as some other interfaces in the same price range that give you a knob to set your own balance between recorded tracks and your mic but it's better than nothing.

As for buffer size, I tend to use the largest I can get away with give what I'm working on.  If for some reason I can't use direct monitoring, I'll set the buffer as small as it can be and still give a clean recording.  I'll generally turn off effects etc (or at least pre render them) and obviously have NOTHING else running on my computer.

On the other hand, when mixing, I'll often crank up the buffer size to to ridiculously high number, simply to allow the use of numerous tracks and effects without the need to pre render.  If a big buffer gives me a slight lag when I hit record, it's virtually un-noticeable and not a problem.