You have a good point... a "typical" person will not perceive delays up to 15-20ms (even on the same signal, it just manifests itself as a timbre change).
 
To help "reset" you... the speed of sound through air is roughly 1 foot/sec... so if you are 6 feet from an amp you are seeing the same latency. If you are 15' away from your amp does it bother you? Most cables come in 25', so can even get to nearly 25ms!! I rarely hear folks say "Man... I cannot play with this!"
 
A lot of "latency" turns out to be "mental conditioning;" only when people "see numbers" does it bother them. I posted this a while ago on how delays (same signal) are perceived, but it is not until you understand how you perceive them that they suddenly make sense.

I'm messing around with my current setup trying to increase the round trip latency and see how much it screws up my playing. It occurred to me yesterday that we are talking about milliseconds

That is a really good idea!
 
I know we're talking about milliseconds - but when I'm playing my guitar quietly, through headphones - I can hear the actual electric guitar strings being plucked *and* the (delayed by a few milliseconds) sound coming out through the amp sim etc. It *is* annoying when it's more than 8-10 ms.
Try it yourself - set big buffers, to get a RT latency of 20ms or so. If that doesn't bother you - than any audio interface will be great. If it does - find out how low you need to go.
 
Please let us know how you make out ;-)

Larry Jones

ampfixer
I run my UR44 at 64 samples recording at 24/48. All I do is small projects but it's a great unit with tons of features. I've yet to play with the ability to output 2 different headphone mixes, but I'm sure it will be useful. From what I can tell the 4 amp sims are based on the Yamaha DG series. The included reverb has everything I need and has become my go to.

John - Are the amp sims built into the hardware, or are they VSTs that work only with the host? That is, can you use them as part of the "near-zero latency" monitoring setup, or only through your DAW?

It has onboard DSP for monitoring fx but also VST3 versions of the same plugins are provided. That's a nice touch allowing you to add back the same fx after you've tracked your vocal/instrument.

Quote from their website:
"UR44 offers VST 3 versions of the onboard DSP plug-ins offering useful sound-shaping and FX tools: the Sweet Spot Morphing Channel Strip, the REV-X reverb and Guitar Amp Classics."
This page. See basic fx suite:
http://www.steinberg.net/...eries/models/ur44.html

 
 
Since I finally got around to re-installing Platinum (Foxboro), I figured no time like the present to stress test the 32 sample buffer using GR5 on "HI" CPU settings, and the new "Upsampling." If I cannot break it, it is "damn good"... and well... I couldn't break it (yet). 127 sample round trip at 44.1K (is fast enough I wouldn't be able to tell if this number is BS, since I cannot hear it).
 
 
And performance from inside Platinum - GR5 CPU hit 14% max, and GR5 was upsampled (although I heard no difference)... also ran GR5's out through Focusrite's Red EQ (VST3). Went for about an hour, then got bored, but took a capture to show the comp didn't explode (no pops, crackles, or anything). This is one of only 2 audio tracks in the project, so could easily overload the 32 sample thing with more tracks/effects.
 
 
Again, this is firewire (so no potential USB conflicts) although is running through the onboard VIA chipset (folks often recommend TI only). MixControl version 3.4.
 
Edit: The upsample actually means nothing to the CPU as this was not a bounce!

Well here's a screen shot from my Loopback test thread, As you see I'm at 44.1 and I think the buffer is at 256ms. So I can get this down to around 8 if I lower the buffer. And I guess it will also go down if I up the clock rate. I'll try it next time I turn it on. This is a Scarlett 6i6. And I do believe an i7 processor would improve the RTL,?? My processor is budget. 
 
 

mettelus

I just realized I misled you a bit before. Since I reloaded this machine there is an additional "Firewire Driver Latency" setting which defaulted to "Medium" which I since set to "Short" (the numbers I quoted above were with it set to medium). This maybe a Firewire device only feature (not sure what the USB versions of MixControl have??), and can only bet set when the device is not locked to a program.

 

 
Since I finally got around to re-installing Platinum (Foxboro), I figured no time like the present to stress test the 32 sample buffer using GR5 on "HI" CPU settings, and the new "Upsampling." If I cannot break it, it is "damn good"... and well... I couldn't break it (yet). 127 sample round trip at 44.1K (is fast enough I wouldn't be able to tell if this number is BS, since I cannot hear it).
 

 
And performance from inside Platinum - GR5 CPU hit 14% max, and GR5 was upsampled (although I heard no difference)... also ran GR5's out through Focusrite's Red EQ (VST3). Went for about an hour, then got bored, but took a capture to show the comp didn't explode (no pops, crackles, or anything). This is one of only 2 audio tracks in the project, so could easily overload the 32 sample thing with more tracks/effects.
 

 
Again, this is firewire (so no potential USB conflicts) although is running through the onboard VIA chipset (folks often recommend TI only). MixControl version 3.4.
 
Edit: The upsample actually means nothing to the CPU as this was not a bounce!

That is some low latency you got there! :-)
32 sample buffer is pretty low. I have read, hear an elsewhere, that there are internal safety buffers and some manufactures use more than others. Still, 2.9ms round trip! wow!

Not many systems are stable at that setting. 64 is as low as most people can go. For me I think its 128 but I don't really need to work at that setting so I leave it at 256. 
I've set mine low a few times to mess with Guitar Rig but I never use sims on my guitars as I have  good amps and a stomp box rig so I'm happy with that. 

Yeah, I would never use that as a default setting, just wanted to try it out to see what happened. TBH my buffer is normally 96 or 128 when tracking.

Although it would be interesting to find where the "belly up" point occurred. Also I am curious if the loopback offset changes.

Again... This is only one part of the entire system from string attack to ear drum (take it with a grain of salt)!

mettelus
Yeah, I would never use that as a default setting, just wanted to try it out to see what happened. TBH my buffer is normally 96 or 128 when tracking.

Although it would be interesting to find where the "belly up" point occurred. Also I am curious if the loopback offset changes.

Again... This is only one part of the entire system from string attack to ear drum (take it with a grain of salt)!

Thanks for doing the tests and posting. It is interesting info.
 
I may be needing a new interface soon so I am taking notes :-)

I circled back on this and found something "odd" using CEntrance's ASIO Latency Tester from this thread
(is a neat thread to read for loopback latency/offset).
 
Bottom line, I started of lazy and just tried the latency tester with 32 sample buffer... first offset was 32, then 52, then 206 and seemed to "settle" there. Since this is almost 3 times what I know it is at 64/128 (76), I then reset the interface to 128 samples and the Latency Tester jumped into the 400's.
 
Since I know this is not true, I closed out everything, set my AI back to 32 samples and jumped into SPlat. I still had the loopback project I created, so simply ran the test again, and hit perfect on tracking with the 76 sample offset already enabled (my prefs are set there now). So the offset didn't change with the 32 sample buffer (external loopback is 76 samples, internal loopback is 6 samples).
 
Be advised... if doing a physical loopback test (cables from AI outputs to AI inputs), be sure to zero inputs and outputs before moving any cables and MUTE the track to be recorded before arming it (and leave it muted until the track is unarmed)!!! Do not willy-nilly test this without understanding how to protect your gear.