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harware synth latency in cubase sx3
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kyro prophet
Started Topics :
5
Posts :
7
Posted : Oct 24, 2007 16:55
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my nord lead 3 is connected to my motu ultralite firewire audio interface. the synth analogue outputs are set up to go into the soundcard inputs and the synth midi in/out is routed to the soundcard out/in respectively.
my routing setup to use my hardware synth is set up the way the cubase manual describes where my external instrument is set up to emulate a vst instrument. i route a normal midi track to the external instrument "vst".
in the vst instruments panel when i click the "e" button next to my synth the dialogue is different from a normal vst, instead of seeing the synth there is only a little box that has a slider labelled delay (range is 0-100ms) and another slider labelled output gain. adjusting the delay slider does nothing to the latency i measure.
the way i measured the latency is from routing the cubase master output to an audio input channel on my soundcard and then sending that signal back into cubase on an audio track and recording that channel in real time in cubase. i realise that this routing will induce a little bit of latency, but that amount is small--only as big as the sample buffer
the problem that i am seeing is that when i use my sequencer to playback midi there is a 50 ms latency from (i assume) the signal chain that is involved:
1) the sequencer must send the midi data to the firewire interface
2) the interface then sends midi to the synth
3) the synth sends audio to the soundcard
4) the soundcard sends audio to the sequencer
5) additional delay is added with insert effects
as i mentioned, this delay is about 50 ms, which is unacceptable for a bass for example, where the timing must be perfect. my solution is to offset all the midi 1/32 earlier so that the delay is compensated. i am looking for a better solution though, so that tempo synced effects like gates or arpegiation can work for me!
cubase offers full signal path delay compensation, and when i click the little icon in the top left to "constrain delay compensation" the delay is lower--about 30 ms. this is still too much though, plus it means i can't use my UAD PCI card effects!
p.s. my buffer is 256 samples.
when i reduce the buffer to 128 samples the delay is about 36 ms, and when i also constrain delay compensation in addition to the smaller buffer the latency problem is fixed.
any suggestions about a better routing strategy would be great! i hope that someone out there who has more experience with hard synths might answer this (i was raised on softsynths!) thanks 
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ThiagoNAKA
IsraTrance Full Member
Started Topics :
104
Posts :
1047
Posted : Oct 24, 2007 17:50
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I guess there´s nothing more to do...
Maybe try to check "lower latency" on Device Setup.
But my advice is to bounce the synth to wav. Specially bass. It would be very hard to sync your Nord to the host tempo.
 LOADING... |
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Colin OOOD
Moderator
Started Topics :
95
Posts :
5380
Posted : Oct 24, 2007 18:24
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Only steps 4) and 5) in your list will introduce significant latency. You need to measure the actual latency between SX sending out prerecorded MIDI and the actual audio coming from your NL3 back into SX - the way you are doing this is fine but you want to remove the plugins. Then you can adjust the playback latency with the slider in the NL1's instrument channel edit window. I think that because you tell SX which audio input the synth is outputting to, it will be able to further compensate for any latency due to plugins on the NL3's SX input channel but - because SX doesn't normally know the source of any audio it records - it might be necessary to manually compensate (as above) each time you change plugins on the NL3 if you're insistent on wanting to hear the NL3 live through plugins. This isn't a defect in SX as such, it's a 'laws of physics' thing. The way to get round it the latency problem is when you're playing/recording the NL3, to monitor it directly through the MOTU rather than SX. This will mean you'll have to record the NL3 as audio to audio if you want to hear it through plugins.
AFAIK, 'Constrain Delay Compensation' turns off plugins which introduce more than a certain amount of latency, the exact value being dependant on the soundcard latency.
You will never be able to compensate for latency with live played input (unless you play the keyboard in advance of the notes you want to hear!).
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