From: Tobiah <toby@tobiah.org>

I've never been able to get reliable low-latency audio under windows.
I've spent many hours looking through lists of tweaks, like power profile settings and countless other magic incantations that never seemed to
make a difference. I've also never gotten LatencyMon to run for very
long without the red flag.

My largest need for the low latency is for playing sampled pianos
and other instruments. I've been using a PreSonus Studio 18|10,
and the smallest buffer size I can use without clicks is 256 samples
at 44100Hz. Any smaller than that, and it mostly works, but I get
little clicks periodically. Now, some would say that 256 samples
is small enough, but I can really tell the difference when playing
a digital piano; I can feel the difference between 128 and 64 as
well. After that the change is imperceptible.

So I came across a Scarlett 2i2 and tried it out and found that
I could use a 64 sample buffer size (this is using Reaper) and it
seems rock solid. This got me to thinking maybe Focusrite does a better
job with drivers, so I started shopping for a more capable
Scarlett.

Then I thought that the Presonus, having so many channels, is probably
taking most of the USB bandwidth, and the lowly 2 in, 2 out Focusrite
is may be enjoying an unfair advantage.

Now, I'm on a ThinkPad at the moment, so I get that I may not be
able to expect as much as from a well-built desktop. I went through
dozens of tweaks though, and all I got to show for it was the laptop
fan running more often, and louder.

Having spent so long Googling and performing low-latency tweaks, I
didn't know where to start backing out the changes, so I went for a
fresh Windows install, which was badly needed anyway.

The Scarlett still dutifully handles a 64 sample buffer. I'd
spring for a 18i16 4th gen, but I still have my concern that the
2i2 may only be performing better because of the low number of
channels.

Another question: if the large number of channels over usb 2.0
is indeed a concern, would I do better with a USB-C interface?
What if that cable also carries the monitor signal?


Thanks

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* Origin: rbb sglnx - the fidonet nntp junction (2:221/10)

From: Tobiah <toby@tobiah.org>

So I found a utility called 'RTL' that measures true latency by
actually timing the round trip from input to output through a cable.
Mind a little blown. Buffer size is only tangentially related
to hard latency figures. The Presonus, using a 256 sample buffer
scores around 12ms, same as the Scarlett with a 64 sample buffer!
The best figure I could get out of the Scarlett with any buffer
size (safe mode off) was about 10ms. The Presonus can do 3.855ms
at 16 samples, although as I mentioned, the best stable buffer
size I can use with the Presonus is 128, but that yields around 7ms.

There are always so many layers to peel through with this stuff.




On 1/25/2026 4:25 PM, Tobiah wrote:

I've never been able to get reliable low-latency audio under windows.
I've spent many hours looking through lists of tweaks, like power profile settings and countless other magic incantations that never seemed to
make a difference.  I've also never gotten LatencyMon to run for very
long without the red flag.

My largest need for the low latency is for playing sampled pianos
and other instruments.  I've been using a PreSonus Studio 18|10,
and the smallest buffer size I can use without clicks is 256 samples
at 44100Hz.  Any smaller than that, and it mostly works, but I get
little clicks periodically.  Now, some would say that 256 samples
is small enough, but I can really tell the difference when playing
a digital piano; I can feel the difference between 128 and 64 as
well.  After that the change is imperceptible.

So I came across a Scarlett 2i2 and tried it out and found that
I could use a 64 sample buffer size (this is using Reaper) and it
seems rock solid.  This got me to thinking maybe Focusrite does a better
job with drivers, so I started shopping for a more capable
Scarlett.

Then I thought that the Presonus, having so many channels, is probably
taking most of the USB bandwidth, and the lowly 2 in, 2 out Focusrite
is may be enjoying an unfair advantage.

Now, I'm on a ThinkPad at the moment, so I get that I may not be
able to expect as much as from a well-built desktop.  I went through
dozens of tweaks though, and all I got to show for it was the laptop
fan running more often, and louder.

Having spent so long Googling and performing low-latency tweaks, I
didn't know where to start backing out the changes, so I went for a
fresh Windows install, which was badly needed anyway.

The Scarlett still dutifully handles a 64 sample buffer.  I'd
spring for a 18i16 4th gen, but I still have my concern that the
2i2 may only be performing better because of the low number of
channels.

Another question:  if the large number of channels over usb 2.0
is indeed a concern, would I do better with a USB-C interface?
What if that cable also carries the monitor signal?

Thanks

---
* Origin: rbb sglnx - the fidonet nntp junction (2:221/10)