FM9 Latency - Around 5ms?

Randalljax said:
That’s reasonable I think
I wonder if FM3 is lower ?
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Well, I suppose if you only use an amp and cab. The max I can get it to is 5.6ms which isn’t bad alone but the cumulative latency of your whole system is the concern I guess.

I just assumed it would be lower.
 
Hi! I wrote about this in the 5.01 firmware thread.

I did the same tests with my daw and compared it with my (ex)Kemper, because its latency never bothered me, but my new Fm9 feels a little bit disconnected.

Anyway, I hope it's a firmware thing, because it's sounds amazing, but feels a bit strange.

Kind regards!
 
sprint said:
yup, here we goes again

🙄
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Not really. As I said, in itself it’s not an issue. The issue starts to manifest when you’re maybe using a digital wireless, going into digital desks, maybe digital IEM transmitters etc. It can build up.

Every gig I do is on ears so it can be noticeable, as it was with an early Quad Cortex firmware.
 
Random Hero said:
Does this sound right? I'm getting around 202 samples / 4.2ms with just an amp and cab block in the grid. This increases to 235 samples / 4.9ms with a drive block. Adding a delay and reverb doesn't seem to affect it. FWIW, just an input and output block shows as 87 samples or 1.81ms. Granted, even with a loaded up lead sound, it only gets to 5.6ms but that's slower than the Kemper's constant latency setting which is around 4.9ms I think. It's often lower than that.

I thought these were supposed to be around 3ms? Is it a firmware thing?
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With just an amp the latency will be 3.3ms. Adding a cab may or may not increase latency, depends on whether the IR has any leading silence. Adding a drive will add 0.67ms.

So with Drive->Amp->Cab the best you can achieve is 4ms. Any leading silence in the IR will add to this figure.

We could add a "low-latency" mode to the FM products like in the Axe-Fx. This is what Line6 uses (and perhaps other companies). I'm not a fan of this approach because it causes phase distortion which affects the high-frequency harmonics when doing nonlinear processing.

As I've said before it's all a delicate balancing act. Engineering is about trade-offs. If you want the lowest latency possible then your frame size needs to be very small but then you'll either need prohibitively costly amounts of processing power or crappy algorithms that don't use much CPU.

You can also trade-off interpolation/decimation kernels. You can use a smaller kernel length but then your transition band and stop band performance suffers.

Or you can do what Line6 does and use minimum-phase kernels which distort the phase response.

I personally prefer linear-phase kernels with at least 100 dB of stop-band rejection.

If we were to use minimum-phase kernels the latency in this case would drop to about 2.7ms (if my math is right).
 
FractalAudio said:
With just an amp the latency will be 3.3ms. Adding a cab may or may not increase latency, depends on whether the IR has any leading silence. Adding a drive will add 0.67ms.

So with Drive->Amp->Cab the best you can achieve is 4ms. Any leading silence in the IR will add to this figure.

We could add a "low-latency" mode to the FM products like in the Axe-Fx. This is what Line6 uses (and perhaps other companies). I'm not a fan of this approach because it causes phase distortion which affects the high-frequency harmonics when doing nonlinear processing.

As I've said before it's all a delicate balancing act. Engineering is about trade-offs. If you want the lowest latency possible then your frame size needs to be very small but then you'll either need prohibitively costly amounts of processing power or crappy algorithms that don't use much CPU.

You can also trade-off interpolation/decimation kernels. You can use a smaller kernel length but then your transition band and stop band performance suffers.

Or you can do what Line6 does and use minimum-phase kernels which distort the phase response.

I personally prefer linear-phase kernels with at least 100 dB of stop-band rejection.

If we were to use minimum-phase kernels the latency in this case would drop to about 2.7ms (if my math is right).
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How does the second method you mentioned smaller kernel impact tone and performance
What are the negative impacts of stop band or transition to the overall sound
 
sprint said:
+ throw in a few more ms with an outboard pedal, and you can suddenly be into noticeable territory. The familiar: "Xms = Xfeet, so don't worry about it" type comment is hilarious since it's cumulative latency that often sneaks up and bites you.

edit: so it makes sense to want every digital component in a signal chain to be as abdolutely low in latency as possible.
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This is why we need pedal based AD/DA converters with plenty of IO and why all serious digital gear needs digital IO. The industry just isn’t there yet and may never be. The majority of players (including myself) aren’t having a problem and the amount of total latency is acceptable. But having a solution to cut the number down to next to nothing is a good idea, too. Daisy chain the digital IO of all your pedals, and maybe some kind of master clock to keep it all synced that’ll do SRC if needed. I don’t know. A little too heady for me but this should probably happen.
 
FractalAudio said:
With just an amp the latency will be 3.3ms. Adding a cab may or may not increase latency, depends on whether the IR has any leading silence. Adding a drive will add 0.67ms.

So with Drive->Amp->Cab the best you can achieve is 4ms. Any leading silence in the IR will add to this figure.

We could add a "low-latency" mode to the FM products like in the Axe-Fx. This is what Line6 uses (and perhaps other companies). I'm not a fan of this approach because it causes phase distortion which affects the high-frequency harmonics when doing nonlinear processing.

As I've said before it's all a delicate balancing act. Engineering is about trade-offs. If you want the lowest latency possible then your frame size needs to be very small but then you'll either need prohibitively costly amounts of processing power or crappy algorithms that don't use much CPU.

You can also trade-off interpolation/decimation kernels. You can use a smaller kernel length but then your transition band and stop band performance suffers.

Or you can do what Line6 does and use minimum-phase kernels which distort the phase response.

I personally prefer linear-phase kernels with at least 100 dB of stop-band rejection.

If we were to use minimum-phase kernels the latency in this case would drop to about 2.7ms (if my math is right).
Click to expand...
Thanks for the details (mostly over my head). I suppose the option to choose lower latency vs better accuracy could be useful for those who want it but I defer to your judgement.

I think a key question raised in this thread that you didn't talk about is why the FM3 latency is more in line with the Axe Fx III than the FM9. Curious about the results there...
 
unix-guy said:
Thanks for the details (mostly over my head). I suppose the option to choose lower latency vs better accuracy could be useful for those who want it but I defer to your judgement.

I think a key question raised in this thread that you didn't talk about is why the FM3 latency is more in line with the Axe Fx III than the FM9. Curious about the results there...
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Agreed and for the record I find this an interesting discussion and wonder the same thing .
For instance if someone was using 2 amp blocks on the FM9 could we assume the FM3 with its 1 amp block would be lower in latency ?

A switch like the Axe3 maybe would be a cool addition but obviously the AX3 has way more CPU , so perhaps using that in the FM would create more noticeable audio artifacts ?
 
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