MIDI synchronization of DAW with external sequencer

[HomeProducer]

I would like to synchronize an MPC 2500 or Motif ES to my PC.

I have different sequencer programs: Cubase, Record, Sonar.

My main question is:

If the DAW is the master, things are clear.

What if the MPC is the master and provides midi clock?

The program has to play/record audio and also has to re-synchronize to the midi clock!
How can a program as a slave stay in sync without time-stretching?

Or do the clocks drift slowly out of sync when the midi sequencer (MPC or Motif)
is the master?

A program like propellerheads Record does only support slave mode.

[bluemoon]

it's very hard or at least I could never do it.

Best results I got, and the way I do this, is to have the DAW as master and use a firewire midi interface (midi in your sound card)

someone here may have a better solution though

[Leon EA]

Cubase can't slave to MIDI clock. It has to be master.

[HomeProducer]

Originally Posted by Leon EA

Cubase can't slave to MIDI clock. It has to be master.

can you at least use mmc commands from mpc?
start, stop, ...

[Altitude909]

Originally Posted by HomeProducer

can you at least use mmc commands from mpc?
start, stop, ...

Sure but what use is that, so you can get them to not run in sync at the same time?. Cubase will slave to MTC if the mpc sends that

[HomeProducer]

Originally Posted by Altitude909

Sure but what use is that, so you can get them to not run in sync at the same time?. Cubase will slave to MTC if the mpc sends that

ok, mpc 2500 is able to provide MTC. But how does Cubase tackle the
problem? Time Stretching?

regards

[crufty]

not sure i have an answer...it's just crazy that a second generation $500 groovebox (electribe) can figure out if it should be master or slave automatically, but 15+ year $2000 solution can't even be forced to slave...

[HomeProducer]

Originally Posted by crufty

not sure i have an answer...it's just crazy that a second generation $500 groovebox (electribe) can figure out if it should be master or slave automatically, but 15+ year $2000 solution can't even be forced to slave...

don't know if you mean the DAW or the MPC.

The MPC is able to be set as master or slave with the updated os.

The DAW has the problem that it must record and play continuous wavefiles. Therefore, being the slave is not straightforward like for an electribe, which just has to fire out short samples. For the electribe you have to re-synchronize the sequencer and not an audiostream, which is much simpler.

[crufty]

meant the daw...

i'm not sure I follow why it's impossible* for the daw. It already has a global tempo track right? lock on to the beat and follow it.

*edit: hard yes, impossible no... nothing is ever easy w/midi!!!

[lain2097]

MTC/SMPTE =/= beat clock or tempo.

SMPTE is an absolute amount of time were tempo has no bearing on. Within SMPTE your tempos can change without affecting the track time. This gets further complicated by which frame count you're using (29.99,24d, etc).

I've been looking for a similar solution to Logic synchronising my DAT deck via MTC. Currently I can only get MMC commands to work

All kinds of video gear can sync with no problem (it's very simple: master/slave & type), but DAWs/sequencers have this nagging problem or gotcas!!!

[Altitude909]

Originally Posted by HomeProducer

ok, mpc 2500 is able to provide MTC. But how does Cubase tackle the
problem? Time Stretching?

regards

Not sure what you mean. You can musically time stretch the audio to the time base but it wont do it realtime. MTC is for allowing the DAW to function as a tape machine (and what it was designed for in the first place) so anything recorded while the MPC is controlling the show will already be at the right tempo anyway.. Honestly, I cant see any reason to control a computer DAW which expects to be in charge with an external sequencer, you're really just asking for car loads of problems

[HomeProducer]

Originally Posted by Altitude909

Not sure what you mean. You can musically time stretch the audio to the time base but it wont do it realtime. MTC is for allowing the DAW to function as a tape machine (and what it was designed for in the first place) so anything recorded while the MPC is controlling the show will already be at the right tempo anyway.. Honestly, I cant see any reason to control a computer DAW which expects to be in charge with an external sequencer, you're really just asking for car loads of problems

Okay how I understand it:

The DAW has a clock. This clock is synced to the beat and synced to the audio stream. Normally there would be a constant Ratio between the passing beats and the number of recorded samples if the DAW is the master.

Lets suppose the DAW is the master. Then it always can assign the first beat in a bar to some sample in the stream with regular distances between such marked samples.

Now lets suppose the DAW is the slave. Then during recording things are recorded linearly in time without time stretching. Because the clock of the external master is slightly different, and the DAW will track it, it will probably assign different stream samples to the beat (mark them as the "1" ) then it would do if it was the master. That is still "ok".

Now things get complicated when the DAW wants to track the timing of the master when audio files are already recorded. How does it track these streams and align them to the master clock? Imagine, the master has changed and the new master has a different clock with different error. So either the DAW performs some real-time time stretching or the stream will drift away from the new clock. For example: the audio file could be some drum loop and in order to align this drum loop to the external clock, the drum loop must be time stretched.

[Altitude909]

Originally Posted by HomeProducer

Okay how I understand it:

The DAW has a clock. This clock is synced to the beat and synced to the audio stream. Normally there would be a constant Ratio between the passing beats and the number of recorded samples if the DAW is the master.

Lets suppose the DAW is the master. Then it always can assign the first beat in a bar to some sample in the stream with regular distances between such marked samples.

Now lets suppose the DAW is the slave. Then during recording things are recorded linearly in time without time stretching. Because the clock of the external master is slightly different, and the DAW will track it, it will probably assign different stream samples to the beat (mark them as the "1" ) then it would do if it was the master. That is still "ok".

Now things get complicated when the DAW wants to track the timing of the master when audio files are already recorded. How does it track these streams and align them to the master clock? Imagine, the master has changed and the new master has a different clock with different error. So either the DAW performs some real-time time stretching or the stream will drift away from the new clock. For example: the audio file could be some drum loop and in order to align this drum loop to the external clock, the drum loop must be time stretched.

mtc clock and sample clock are not synchronized and not related. Sample clock runs into the kHz range while the midi rate is 30 frames per second, getting those two in sync = no fun. The DAW can be running at a completely different sample clock and it would not have any bearing on the MTC sync. All MTC does is send information on where it is in the host sequence based on 30 frames per second. It was made for syncing midi to a SMTPE track, thats all.

[HomeProducer]

Originally Posted by Altitude909

mtc clock and sample clock are not synchronized and not related. Sample clock runs into the kHz range while the midi rate is 30 frames per second, getting those two in sync = no fun. The DAW can be running at a completely different sample clock and it would not have any bearing on the MTC sync. All MTC does is send information on where it is in the host sequence based on 30 frames per second. It was made for syncing midi to a SMTPE track, thats all.

sorry I don't get it.

Of course sample clock is 44.1 kHz (or 96 kHz or whatever).

And midi frame rate is much lower. But still: midi clock or absolute counted sample position both
relate to a timing position within the audio stream.

If a audio tape recorder is the slave and measures that some current playback
position is slightly ahead or behind the received midi clock, it must slightly slow down
or accelerate the tape speed in order to correct timing. This is a control loop.

Same thing for the DAW, but here the acceleration can only be realized with
time stretching during playback, for my understanding.

This would also explain why Ableton can do it, because it has real-time time-stretching.

[crufty]

so midi clock is out what about mtc?

[HomeProducer]

Originally Posted by crufty

so midi clock is out what about mtc?

same problem of course!

[crufty]

cubase and logic can slave to mtc. if your mpc can send mtc you are done

[MikeyMike]

Try this.

YouTube - Track and Sync MPC with DAW

YouTube - Sync MPC, Fantom, and Logic Pro 8

Clock Sync, SMPTE, MTC and MMC

[Leon EA]

Originally Posted by HomeProducer

sorry I don't get it.

Of course sample clock is 44.1 kHz (or 96 kHz or whatever).

And midi frame rate is much lower. But still: midi clock or absolute counted sample position both
relate to a timing position within the audio stream.

It's not that simple.

The issue of syncing a digital workstation lies in the fact that there are 3 different types of synchronisation exist which are mixed up, like the comments in this thread reveal.

-tempo: MIDI Clock, or MIDI Beat Clock
-Time Code (absolute position): MTC, SMPTE, LTC (among others)
-clock: Word Clock, any digital connection

Now, the latter is the culprit. In order to slave a DAW, you will have to control its speed using a digital clock. Cubase and most other DAWs use the so called jam sync method, which is that at a start command, it puts the cursor at the position given by the time code (MTC). From there, it *IGNORES* the time code and runs its speed by the clock - which comes from your AUDIO CARD. 44.1kHz is not always exactly that speed, and especially when syncing to other devices with a less stable clock (better said, speed) (tape based digital units like DAT, ADAT, Digibeta, or their analog predecessors using synchronisers for exactly this issue), the results will vary. If you sync a DAW (or any recording/playback device) with only time code, the units will drift apart and your tracks are not in sync anymore, audible from a certain point.

So, to slave a DAW to an MPC, you need to feed the MTC signal in a synchronizer that resolves that time code to a digital clock signal (typically word clock). The MOTU Midi Time Piece AV is one of a few units that does this. Rosendahl has a MTC-SMPTE converter (MIF) but you will need a device that converts the SMPTE to a valid clock signal (LynxTwo does this, RME TCO daughterboard and the EMU sync daughterboard as well, so does the old Rosendahl WIF, rebranded by Steinberg as Nuendo Timelock Pro).
Another method would be to put a recorded SMPTE recording on an MPC track and feed this to one of the above methods. This is how it was done in tape days, track 24 was time code and track 23 was empty for crosstalk reasons (you don't want that aggressive clock sound to leak through a recording). You'll need to set your Cubase song to the time range of that SMPTE track in order to work with it, of course.

I don't know Ableton Live very well, but its realtime time stretching is unlikely to solve this all by itself since it can't discover whether there would be a sync issue or not.