Lightpipe transfers: snap crackle and pop!

P

parkbirds

New member
Well,

While my programs are in 'standby' (for lack of a better word) by audio out likes to do this load pop, snap... you get it. It does not do this while playing though.. So, what is going on? I'm using just one adat, and using the lightpipe in for the digital input to monitor what is on the computer, but I really have not figured where the noise is coming from. I tried unplugging the lightpipe chain that was not in use, but that does nothing (i.e. while listening I unplugged the output of the adat and in the input on the computer).

Anyway, I'm new to this, and beyond softare problems which I'm having, I'm baffled as far as hardware problems.

Thanks!
 
You have to set your recieving device clock to slave to the incoming lightpipe data.
 
What Track Rat said.

There are some other things that you have to consider in digital clocking too. I am sharing this just to give you an idea of how silly these problems can be sometimes! :)

I was recently doing a mix where the gear involved was:

Yamaha O2R console with the ADAT cards installed

Alesis HD24 (lightpipe output to the ADAT cards on the O2R)

Alesis XT 20 (lightpipe output to the ADAT cards on the O2R)

Alesis BRC (this not only serves as the transport master for the HD24, but also as the digital clock master to the everything....)

The XT20 was just being used as a way to import more effect returns to the O2R (since it only had 4 stereo return channels, and I had 6 mono effects I needed for this mix, and I needed seperate eq's for all the effects at the console, this was the best way to come back in...)

Anyway, we did a remodel of the studio that finished a few weeks before, so everything was rewired, mostly by the studio owner. The XT 20 usually just sits around doing nothing. So this was the first time I had used it.

Anyway, I kept getting the SAME EXACT problem you had. What I came to find out was that the owner forgot to hook up the Sync cable between the HD24 and the XT 20!!!

The HD24, O2R, and XT 20 all get their word clock via the BRC. With the Sync cable NOT being hooked up between the HD24 and the XT 20, the XT 20 was not getting word clock from the BRC. I hooked up the cable, rebooted everything, and vola! popping and clicking gone.

So, you not only have to make sure that your lightpipe in's are syncing to incoming word clock (on the O2R, there is a way to actually just sync to the Lightpipe inputs if you choose), you have to make sure that relative clock is going to other decks in the system, as is the case with ADAT's, only one ADAT is the master clock.

Anyway, just a fun little story and a little learning experience.

Ed
 
adat experience

Yep..also make sure if you're using multiple ADATs that one of them is master and the rest are all in slave mode..and that their bitrate <16/20> and sampling frequency <44/48> match.

...ALSO.. If you ever use the ADAT/EDIT PCI card..make sure the harddrive you're using is defragged..or you'll get pops, clicks, dropouts, etc...
 
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