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latency blues

Discussion in 'Studio Techniques' started by peterlemer, Jul 11, 2009.

  1. peterlemer

    peterlemer Senior member

    highly melodyned song ( mentioned elsewhere) with comp + eq plugins on 4 horns, 5 vocals; some sonalksis multicomps on vocal and horn submixes and maximiser on master out.

    I converted my Superior Drummer 2 audio instrument drum track to audio and removed SD2 plugin.

    Tried re-recording a double bass and found that even when bypassed, the sonalksis maximiser caused recording foldback latency.

    Q1: why would this be?

    Set the master to no plugin and the foldback latency disappeared.
    Recorded the bass, and the recorded track was -1/16. -240 late ( the correction need to get the bass back in sync) at 190 bpm.

    Q2: why would this be?

    switched off 'plugin delay compensation' and all the vocals and horns were out of sync. I don't use a DSP card in my mac, but do use RME Fireface 800.

    I could use some coaching on latency with respect to the above!


  3. paulnajar

    paulnajar Senior member

    Is Melodyne running? Via bridge or rewire? Possible latency here.

    In answer to your Q1 - most maximisers use a substantial buffer to work. Bypassing might not bypass the extra buffer.

    Try sending all tracks through a bus (Aux) and putting the maximiser there.

    I'm not 100% sure but I don't think delay compensation works for outputs.
  4. peterlemer

    peterlemer Senior member

    It's running on horns and vocals as a plug-in, but not on the bass track.
    If I didn't have it running the bass player will hear out-of-sync cues because the original pre-melodyned versions were recorded to a poor drum track.

    that means that any overdubs must either be done before end-mixing begins, or any output settings must be saved and the plugin removed.
    Is this what you do?

    Q3. are melodyne regions and plugin settings always saved with a project?
    How do I check?

    L7 manual says nothing about this AFAICT.
    L8 manual says that all audio streams are delayed relative to output AND aux channels

    now, I'm using L7 here, and must assume that the above applies to this unless shown otherwise - in which case your suggestion won't help.

    Having begun this correspondence and reviewed the manuals, ISTM that the more a project gets plugin treatment, the less viable it is to overdub.

    If that's the case, it's a crucial handicap, especially with time-shifted material, and others will have found ways to get round this - I'd love to hear from them

  5. peterlemer

    peterlemer Senior member

    further on latency blues

    I read pages 850-851 L8 manual the answers to most of my questions and assume that the issues are common to L7 even if some of the solutions are not.

    2: " Bypass ( audio and instrument track plugins)... by Option clicking ... eliminates the latency that they create"

    3: " In the All mode, bypassing plug-ins on busses, auxes and outputs will not eliminate the latency... You must actually remove these plug-ins from the Insert slots to eliminate latency"

    In order to overdub onto plugin developed songs I must bypass all audi/instrument track plugins and remove aux and output plugins.

    This, however, leaves me with the problem of not being able to remove Melodyned audio and audio instrument tracks.

    Anyone know how much latency Melodyne introduces?

    If more than 10 msec, I should really bounce the melodyned tracks on L7, and freeze on L8.

    ... i think :)



    PS. will post on Melodyne forum too.
  6. peterlemer

    peterlemer Senior member

    on page 851 it tells me that I have to switch plugin delay compensation from All to Audio/Software Instrument tracks in order to shift plug-in bearing tracks /forward/ in time.

    Why should I need to do so if I follow step 2. above? ( " Bypass ( audio and instrument ... eliminates the latency that they create"
  7. peterlemer

    peterlemer Senior member

    PS. I can also overdub by monitoring the new live input on an external mixer and i disabling software monitoring - according to the manual that means I can leave all plugins in place. If I figure out how to do that with Fireface 800 that could be the solution for me.
  8. johnpitcairn

    johnpitcairn Member

    Monitoring via the Fireface is a good way to go. Put the FF mixer into "submix" mode and select the monitoring channel pair in the bottom row. Now raise the appropriate input faders in the top row. Done.

    You might also want to do a loopback test of the record offset with all your plugins and "all" pdc enabled, just to check that the overdub audio is placed correctly.

    Note also that the monitoring delay through the fireface is approx 90 samples, so if you're really picky you'll set the record delay in Logic to compensate so what you hear is what plays back (if that's how you'll always monitor).
  9. peterlemer

    peterlemer Senior member

    thanks john, will do :)

  10. peterlemer

    peterlemer Senior member

    john - monitoring via Fireface works a dream :) but I've lost the reverb vocalists need to sing to... normally that was part of the Logic mixer - I sent the vocal to an aux with Space Designer.

    How do I manage this now software monitoring is off, and in any case the vocalist is monitoring off-Logic apart from logics output?


  11. Peter Ostry

    Peter Ostry Administrator Staff Member

    Create an Aux channel in Logic, set its input to the input channel where the singer comes in. Put a reverb into the Aux and send the output to your monitor mix. There will be latency but you need a predelay anyway for a monitor reverb. Auxes play always, you don't need to engage software monitoring for that.

    Second option: Plug a hardware reverb into your interface and route it in Totalmix to the headphones.

    Third option: Use a hardware mixer with reverb for monitoring.
  12. Eli

    Eli Senior member

    Fourth option. Leave software monitoring on. Create a pre fader send on your channel strip that is recording the vocals. Insert a software reverb plugin at the destination of that send. When in record enabled mode, pull the fader on the vocal track all the way down to zero (so it doesn't get blended with the direct monitored signal). Dial up some of the prefader send to send signal to the reverb aux.
  13. peterlemer

    peterlemer Senior member

    thanks peter, I like option 1 - will try it

    2. more hardware to install and power - more wires etc. not keen
    3. will need to buy a new mixer :)

  14. peterlemer

    peterlemer Senior member

    Hi Eli - that sounds good, too. I had thought this was possible but hadn't really played with pre-send options before.

    (I'm a keyboardist who is discovering production with no engineering experience so a lot of what I do is suck-and-see )


  15. Eli

    Eli Senior member

    It works great. And on a related note: sometimes when I switch a send to prefader mode - for purposes of tracking with reverb - I end up leaving it in prefader mode afterwards when mixing.

    To me, prefader just "feels" different when mixing. Sometimes I really like it. I know it's kind of semantic, because the same amount of wetness can be achieved by using different post fader values. But I just like the "feel" of prefader mode sometimes.
  16. Peter Ostry

    Peter Ostry Administrator Staff Member

    Don't worry, it will soon become an old mixer ;)
  17. Peter Ostry

    Peter Ostry Administrator Staff Member

    I can imagine that you use a nice trick accidently: If you have a post fader send to a reverb and a compressor later in the chain but before the original sound and the reverb return are summed, the dry signal gets held down on the loud parts while the reverb sees the uncompressed signal. This results in more reverb during the louder parts, more excitement. Not sure if this is the effect you mean but would explain why you like the "feel" sometimes, as you said.
  18. Eli

    Eli Senior member

    Actually, yes; this is what's happening (sometimes). I often have live multitracked drums subgrouped with compression on the subgroup. I have sends on the individual drum tracks (not the kik usually). And when I switch these between pre/post fader, it results in what you described.

    But I have also liked the effect on vocals. But in hindsight, I think it may have been a similar situation - with multi tracked backups bussed to a channel with compression on it.

    So, thanks - I hadn't quite thought of that as being a factor in what I liked about it.:)
  19. peterlemer

    peterlemer Senior member

    peter's option 1 worked today - but I had trouble getting sufficient level off the front of the Fireface - could have added a headphone amplifier in the chain but didn't want to mess with new matrix, so I switched back to doing it all through Logic - as it's a new project, there wasn't much in there to cause latency anyway.

    Tomorrow I'll try Eli's 4th protocol ( nice title for a song) :)

  20. Peter Ostry

    Peter Ostry Administrator Staff Member

    Do you plug the headphones directly into the Fireface's line outputs? :eeek:
  21. peterlemer

    peterlemer Senior member

    yes. that was the first thing to try when experimenting with john's suggestion

    As I hadn't tried it before I had no way of knowing that the ff output was insufficient.

    Apart from level are there any other reasons for your 'eeek' ? :)


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