ADAT causes pops and dropouts

is anyone using the mpc with adat and a 001 or 002? cause there are some glitches..
When I run both the mpc and pro tools with a samperate @ 44100hz, everything goes smooth but when I set both units to 48000hz, random pops, clicks and audio dropouts occure.
Hope someone might know what could be wrong

Dit you check the digital output sync in GLOBAL ? And the sync setting in the digi's control panel? This sounds like you have not setup a good sync.

I recall more people having this problem in the past with the 001/002 I don't own one myself. So a search might help you out here too.

I gree with bleepfreak. Digital pops and stuff are almost always the result of bad digital sync. In a digital setup, there can always be only one master device, the rest must be slave devices. The master device defines the 'word clock' signal, the digital interfaces of the slave devices listen to this word clock signal, and that's the only way they can correctly interpret the samples from the other devices.

hey Rob

I m just curious

does it mean you need a AKAI IB4D card to sync devices connected through ADAT ?

'cos I don't have this IB4D card ((I/O digital and wordclock card) in my MPC and I'm wondering if I should get one or not

I dunno if most studios sync devices using this card or just sync via MIDI or maybe ADAT

could you enlighten me on that one ?

thanx

i know the pops and dropouts are caused by wrong clock settings but this is not the case (i think) as ptle listens to external clock and mpc listens to its internal clock. All is setup good cause everything works well with 44100 samples per second but as soon as i change both machines to 48000hz, those pops occure!
If I set both machines to listen to its own clock, the adat connection works also but then even more pops and clicks occure, less dropouts tho..

I sync via midi tc (mpc = master, ptle = slave)
and want to route the audio through adat.
This is the first time I make adat connections as i havent had adat devices bzefore so i dontknow wich is causing the dropouts.. but I kindo think its pro tools. I have gone through the duc too but no luck ...

is anyone tracking succesfully with mpc & ptle via adat @ 48000hz? Cause its flawless @ 44100hz

Could it be that my adat cable only handles 44100 samples per second? .... btw, the adat cable is only 1 meter in lenght!

Most pro devices with digital audio I/O also have a (software) switch telling the device it's either the master or slave. The mpc4000 has these control switches in the Global/Config page.

I have the SPDIF card installed, not the ADAT card, but I *guess* you get the same kind of control with only the ADAT card installed. It's digital, hence it needs the master/slave control.

You don't need a separate word clock bus (like on the SPDIF card) to transfer word clock from master to slave. It can also be extracted from the digital audio signal.

In the case of our mpc, you can tell it to get the digital sync from either it's internal clock (master setting), or from the DIGITAL IN, ADAT IN or WORDCLOCK inputs.

ikke wrote:I sync via midi tc (mpc = master, ptle = slave)
and want to route the audio through adat.
This is the first time I make adat connections as i havent had adat devices bzefore so i dontknow wich is causing the dropouts.. but I kindo think its pro tools. I have gone through the duc too but no luck ...

is anyone tracking succesfully with mpc & ptle via adat @ 48000hz? Cause its flawless @ 44100hz

Could it be that my adat cable only handles 44100 samples per second? .... btw, the adat cable is only 1 meter in lenght!

As an experiment, you could try to make PT the wordclock master and the mpc the slave. Maybe PT has a problem with syncing to both MIDI and wordclock at that sample rate.

As another experiment, you could change ADAT cables, if you have a spare.

The ADAT outs on the mpc go no higher than 48k, so that should work.

I dont have a wordclock connection..

ikke wrote:I dont have a wordclock connection..

With 'wordclock connection' I meant the digital audio connection.

a k thx

yo

If I understood well, SPDIF connection are those coaxial cables with RCA connectors and ADAT are those fiber optics cables

so what I m wonderin is how much channels can the MPc send through SPDIF ? only 2 ? one by cable ?

about ADAT the connections are one fiber optic goes out and another goes in and each carry 8 channels at a time ? do they self syncrhonize to the other device connected to it ?

thanks for your help I'm quite lost there

Hi Misterv

misterv wrote:
1) If I understood well, SPDIF connection are those coaxial cables with RCA connectors and ADAT are those fiber optics cables

2) so what I m wonderin is how much channels can the MPc send through SPDIF ? only 2 ? one by cable ?

3) about ADAT the connections are one fiber optic goes out and another goes in and each carry 8 channels at a time ?

4) do they self syncrhonize to the other device connected to it ?

thanks for your help I'm quite lost there

1) correct

2) With SPDIF, one cable = 2 channels. So with the SPDIF board you get 2 channels in and 2 channels out. But note that the 2 output channels sent over SPDIF are exactly the same as the Main L/R outs.

3) Yes 8 channels at 44.1 and 48.0 k. but 4 channels when running at 96k. I think this is where the analog outboard beats the ADAT option.

4) No, for a proper transmission you have to set one device as a slave and one as the master so the slave can 'listen' to the clock that exists within the audio signal sent by the master. If you set the (digital out sync) to {internal} in GLOBAL>CONFIG the MPC is master and the other device should be set to slave. Refer to the manual of the other device how to do this. All other settings set the MPC to slave.

Cheers!

thank you verymuch bleepfreak

so if I use, let's say, a Digi 002 with my MPC, and sync these two using ADAT everything should work well ?

no need for SMPTE or MIDI synchronization ?

thanks again

if your trying to get the mp to start the 002 tempo,then thats done through midi,so when you hit play on the mp, the 002 will start and all your MIDI TRACKS will be synchronized,and record the sound going in lightpipe.so if your tracking 8 at a time they will all be the same tempo but having there own MIDI TRACKS & AUDIO CHANNELS.feel me?

Ikke, here are a couple of links to past post about the same problem.

http://www.mpc-forums.com/viewtopic.php ... light=adat

http://www.mpc-forums.com/viewtopic.php ... at&start=0