What to test: Delay Compensation

Reason 9.5 Bug/Issue forum
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skatebird
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Post 28 Apr 2017

Delay Compensation means compensating for the inherent latency in some effect devices. Without Delay Compensation, some signal paths will be delayed relative to others, resulting in phasing, blurred timing, etc. Delay Compensation makes sure all signal paths are in sync.

There are two typical ways to achieve this:
  • By inserting delays on the other signal paths, so that all paths are delayed equally.
  • By having some tracks (the ones with latency effects in their paths) play back earlier.
The Delay Compensation introduced in Reason 9.5 uses the first method only, and there are some limitations as to which signals can be compensated.

We compensate for
  • effect devices that are between a source device (such as an instrument) and its mix channel,
  • effects connected between the To/From Insert FX jacks on any channel device
  • effects connected between the Parallel Out jacks of one channel and the input of another.
These effect devices report their current latency to Reason (hopefully this is a correct figure). On other channels, an internal delay is automatically set accordingly, so that all channels feeding the same bus (or the master section) are in sync.

In addition, the FX sends from channels are delayed where needed, so that they are in sync at the Master Section.

The latencies/delays are also used for positioning audio correctly when bouncing to a new track and when recording audio (with monitor off). We also delay the metronome click so that it isn't heard ahead of the audio.

User interface
  • A Delay Compensation On/Off switch is found to the right in the Transport Panel and in the Master Section of the mixer, next to the Master Fader. This is OFF when you open an old song, but will be ON in new songs (when we get around to doing new template documents).
  • When this is on, the "Total Path Delay" (how much a signal is delayed from playback until it's heard) is shown below this switch. All shown values are in samples, but the tooltip also shows them in milliseconds.
  • On the backside of the audio track/mix channel devices in the rack, if you unfold the Programmer section, is a display showing the insert fx latency for this channel. This is the summed latencies of the effects between the To/From Insert FX jacks.
  • There you will also find an setting for manual adjustment: If you find that you get phasing or other artefacts even though Delay Compensation is on, it may be because an effect doesn't report the correct latency. You can then add or subtract from the reported latency with this control.
  • There is also an indicator there, which lights up if the routings don't allow the latency to be calculated. A tooltip tells you more.
  • At the bottom of the Insert FX section of the channel strips, the Channel FX latency is shown (if any). This is the summed latencies of the effects before the channel input and the effects between the To/From Insert FX jacks, plus the manual adjustment setting. For the Master Section, it's only the summed latencies of the Master Insert FX.
What is NOT compensated?
  • Routing in Reason is free and can be really complex. That's why we've had to limit the Delay Compensation a bit. The following cases are not included in the Delay Compensation:
  • Effect devices that don't directly feed a main mixer channel. For example, if you have connected several instruments via effects (with different latencies) to a Mixer 14:2, these will not be part of the compensation.
  • Channels whose output signals don't pass the Master Section. I.e. the channel (or its output bus) is using Direct Outs.
  • Send Effect devices. Although the sends are compensated, we don't care about inherent latency in the Send Effect devices themselves. For typical send effects like delay and reverb, some latency is typically not a problem.
  • Effect devices fed from one channel, that feed another channel/bus (cross routing).
  • "Special" Insert FX routings such as split (parallel) signal paths between the To/From Insert FX jacks or loopbacks, may make it impossible to calculate a correct latency value. The indicator on the back of the mixer device and its tooltip indicate this.
In addition, it's only audio signals that are compensated (delayed). CV, MIDI and automation are not delayed.

How to test Delay Compensation
  • Find effects that report latency (the MClass Maximizer in Lookahead mode is a safe bet, but there are lots of REs and VST effects that do it too).
  • Add such effects to some channels, and leave other channels without effects. Compare the timing with and without Delay Compensation activated.
  • Test this with parallel channels and busses - make the channel routings complex!
  • Test manual adjustment of channel latency.
  • Try finding effect routings that cause the "Non-standard Routing" indicator to light up on the back of the channel device!
  • Are sends correctly delayed?
  • Bounce in Place and Bounce Mixer Channels - is the rendered audio in sync?
  • Record audio with monitoring off. The audio should be positioned correctly (just like Record Latency Compensation in the preferences compensates for audio hardware i/o latency).
I have nothing to say, and I'm saying it. - John Cage

Marc64
Posts: 481
Joined: 24 Jan 2015

Post 01 May 2017

The delay compensation works wonders.
Tryed it on the BVS512 vocoder in eq mode (fft512) where there are some dalay and it's GONE! :)
You props are the BEST! :) :thumbs_up: :thumbs_up:

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alex
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Location: Italy

Post 07 May 2017

Apparently FXpansion DCAM ChanComp and BusComp REs do not report their latency value (it remains to 0) so no latency compensation takes place (for example in parallel scenario). I still haven't had the chance to try EnvShaper but I suspect that the same behaviour applies.

Should I write to FXpansion asking for an update?
The best things happen after reading the manual. ;)
:reason: :re: :refill: :ignition:

limbophonic
Posts: 54
Joined: 21 Dec 2015

Post 09 May 2017

Hi If a VST does not report any delay as with slate digital virtual mix rack, so i tried the VMG 01 and sent test signal thru slate and result was 0 samples,

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Carly(Poohbear)
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Post 12 May 2017

skatebird wrote:......
I have done quite a bit with testing and I like the end result a lot.

What is the logic behind if something is compensated or not, is it hard-coded as in a lookup table?

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manisnotabird
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Post 16 May 2017

The Audiomatic doesn't seem to be reporting latency at all. Also, the adjust knob for the delay compensation on the back is easily obscured by cables.

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ljekio
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Post 17 May 2017

Bounce in place and bounce master section with Ozone maximizer is works well.
Unlike the previous version (render had silence gap at clip's startpoint there).
Finally :)

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MattiasHG
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Post 17 May 2017

Carly(Poohbear) wrote:
skatebird wrote:......
I have done quite a bit with testing and I like the end result a lot.

What is the logic behind if something is compensated or not, is it hard-coded as in a lookup table?
Devices report their latency through the plug-in or device to us, we compensate based on their reporting.

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ljekio
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Post 17 May 2017

MattiasHG wrote: Devices report their latency through the plug-in or device to us, we compensate based on their reporting.
Mattias, channel strips have screen with latency value, but not at Master section. Do you plan to display it like at channels?

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Carly(Poohbear)
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Post 23 May 2017

ljekio wrote:
MattiasHG wrote: Devices report their latency through the plug-in or device to us, we compensate based on their reporting.
Mattias, channel strips have screen with latency value, but not at Master section. Do you plan to display it like at channels?
Note you can see latency value for the master section in the Mixer (in the master section )...

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geronimo
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Post 09 Jun 2017

When a "Mix Channel" utility is connected to the separate outputs of a VST (KONTAKT, U.V.I or other) if you want to erase only this Mix Channel from the Project, you must disconnect it beforehand.
Otherwise, MIX Channel and Instruments are erased together.

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AttenuationHz
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Post 19 Jul 2017

geronimo wrote:
09 Jun 2017
When a "Mix Channel" utility is connected to the separate outputs of a VST (KONTAKT, U.V.I or other) if you want to erase only this Mix Channel from the Project, you must disconnect it beforehand.
Otherwise, MIX Channel and Instruments are erased together.
CTRL Delete ;)
Waiting for Navigation by Routing to be added! viewtopic.php?p=275484#p275484f=6&t=749 ... 97#p275497
:refill: http://rwrd.io/qx9m5wx Referral!

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geronimo
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Post 20 Jul 2017

AttenuationHz wrote:
19 Jul 2017

CTRL Delete ;)
Nope . :oops:

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selig
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Post 20 Jul 2017

geronimo wrote:
09 Jun 2017
When a "Mix Channel" utility is connected to the separate outputs of a VST (KONTAKT, U.V.I or other) if you want to erase only this Mix Channel from the Project, you must disconnect it beforehand.
Otherwise, MIX Channel and Instruments are erased together.
How to reproduce? With Kontakt, I'm not seeing this, unless I'm missing something obvious.
I'm selecting JUST the additional Mix Channel (in the Rack) which is hooked up to outputs 3/4, and hitting "Delete".

:)
Selig Audio, LLC

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geronimo
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Post 20 Jul 2017

It's true that I did not explain well: I connected the independent outputs of KONTAKT to several Mix Channel utilities located outside the KONTAKT's track .
When you want to erase one of these external Mix Channels, this will erase everything (KONTAKT and all MIX Channel depending or connected).

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LABONERECORDINGS
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Post 20 Jul 2017

See if 'autogroup' is active in the options menu - turn it off so that you should be able to delete separate units instead of bulk delete -
should help a bit more.

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geronimo
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Post 20 Jul 2017

Many thanks; it was the solution _ :thumbs_up:

Contrust
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Joined: 08 Oct 2017

Post 08 Oct 2017

Hello guys,
I got a problem with the delay compensation! Here is a video about that:

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AttenuationHz
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Post 08 Oct 2017

Contrust wrote:
08 Oct 2017
Hello guys,
I got a problem with the delay compensation! Here is a video about that:
What way do you have ozone routed? Delay comp does not work on any sort of AUX chain.
Waiting for Navigation by Routing to be added! viewtopic.php?p=275484#p275484f=6&t=749 ... 97#p275497
:refill: http://rwrd.io/qx9m5wx Referral!

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Carly(Poohbear)
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Post 09 Oct 2017

AttenuationHz wrote:
08 Oct 2017
Contrust wrote:
08 Oct 2017
Hello guys,
I got a problem with the delay compensation! Here is a video about that:
What way do you have ozone routed? Delay comp does not work on any sort of AUX chain.
FYI, I have replied to this on FB, told him to read the chapter on DC page 476 onward, looks like it a routing issues.

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