Re-track External Insert question [Solved]

The real-time delay compensation for an External Insert is done by delaying the playback of other tracks to match the delayed signal returning from the external hardware. This delay compensation works just like Plugin Delay Compensation for plugins working inside the box.
 
When you record with PDC active, the signal is usually from a direct-monitored live performance that's expected to be in sync with the delayed ouput (including the metronome click), and will be compensated for that. The delay for the signal returning from the external hardware to another input has already been compensated by PDC, but SONAR doesn't 'know' that so the recorded audio will end up being over-compensated. But I think you must be mistaken about that 4000-sample discrepancy at a buffer of 512, unless maybe the external hardware is digital, and is introducing a lot of A/D/A conversion and DSP latency on top of the DAW interface latency.
 
In any case. the bottom line is that to render processed output of an EI with proper compensation, you need to do a real-time bounce (i.e. Fast Bounce disabled) to another track, and then bypass the EI and mute/archive the original track.

Hi micv,
Hmm...something seems funny here. If you designate a port as a return port in EI, Sonar shouldn't let you choose that input port as a source for other tracks....at least that's how it works here. So for example, if I set input 67 as a return in EI, I cannot then use input 67 as a source for an audio track.
 
That aside, the way to do this is probably either with Bounce, Freeze, or by routing the output of the track with EI to an aux and recording the aux. You'll get the same result as recording a hardware input and won't (or shouldn't) run into strange PDC behavior.
 
As far as routing to a hardware out and recording back in, delay compensation can't account for that because Sonar has no way of knowing that you're setting up a round trip through your A/D and a piece of hardware and then back in. That's the situation that EI is intended to fix.

Dean

Hunh....yeah Brundle, you're right. I just tried to record from a track with EI on it to an aux and the resultant track was delayed. I would have thought that PDC would handle a track with EI on it in the same way it handles any other plugin. Thanks for pointing that out.
 
OP - Yep, just freeze or bounce.
 
Dean

I spent the last couple evening looking into this carefully.  What I stated earlier about the re-track by routing to port is wrong.  By using a test signal, I was able to measure that at 48k, 512 samples buffer, the re-track was recorded late by 155 samples.  If I add this value to the Asio Manual Offset, the re-track synced up perfectly.
Now I just need to understand what I've observed.

brundlefly
It sounds like you are now compensating for the some EI delay with Manual Offset, which you don't want to do, because Manual Offset will apply to compensation of 'normal' recordings, and they will end up over-compensated.

Not sure about this.  I removed all instances of EI in Sonar and ran test on basically a hardware loopback (In connects to Out).  Nothing but a source track and a record track, so EI shouldn't be in the equation.  Since the Hilo has addition buffer settings (standard. low, etc.) I suspect that it has something to do with the high number.  I can collect more data on different settings.
 

brundlefly
To set Manual Offset, use a tool like the free CEntrance Latency Tester to measure actual round trip latency, subtract whatever is reported in for Total Round-Trip in Preferences > Audio > Driver Settings (usually smaller), and enter that difference (usually positive) as the Manual Offset.
You can also measure the actual round trip using EI with nothing in the loopback path, and add one buffer to that number. It should come out the same as CEntrance.

I did this and confirm that EI's report is one buffer less than CEntrance.
 

brundlefly
Manual Offset should be fixed regardless of buffer size so you shouldn't have to touch it again.

I need to run more test at different buffer but so far at 256 and 512 buffer the Offset is the same, but at 128, the offset is -102.  Just when I thought I got this figured out!!! 
 
A question I have is Is the reported asio latency in Sonar came from the soundcard driver? if so is the below correct?:
CEntrance = HW + asio/usb driver latency.
Sonar reported asio = asio/usb driver +  sonar input-output buffer latency
then
CE - Sonar = HW + sonar input-output buffer

I've just left a link to the online documentation regarding External Inserts. The manual explains it much better than I can.

http://www.cakewalk.com/D...mp;help=Mixing.33.html

Hope it helps.

My recent experience is mostly with PCI(e) interfaces which I like for the very low bus latency. My old E-Mu 1820m required only a 22-sample offset. The MOTU I run now requires 44 because the driver under-reports more, but it has a lower net hardware latency than the 1820m. It adds only 89 samples total to the I/O buffer latency, and that 44-sample offset is all converter latency. It goes away if I use digital I/O.
 
USB interfaces are all over the map in this regard, but I think Lynx are pretty good.
 
Glad to hear you got it all sorted in any case.