• From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Topic: FF400 on 1394b audio dropout

Hi,

It's possibly a topic already covered, and if that is the case, I am sorry about that, let me know where i can find the answer to this problem.

I have a FF400 plugged via the 1394b on my mac pro first generation. Everything was working nicely until I plugged in a new external HD My Book Studio working on 1394b. When the HD is on, the FF400 drop out audio after 5 sec. Sometimes it get back to life but it will not last. The host led turn to red. I was copying files on my HD at that time.

If I disconnect the HD, it's back to normal.

There are two plugs for 1394b behind my mac pro and use each of them for the FF400 and the HD.

I want to know what is causing the drop out on the FF400? Is it just that the HD wants to sync at 800Mb and the FF400 doesn't like this ? Are the 2 FW ports on the same "bus" inside the mac pro?

Of course, I will change my configuration and send my FF400 on a 1394a bus, but I am wondering the cause of this issue.

Thanks!

thejammer's Website

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,558

Re: FF400 on 1394b audio dropout

It seems the driver actually interrupts/disconnects the FW bus here (HOST LED indicates that). Separate FW connections may be the only solution.

Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

Do you think that daisy chaining the HD would be a good idea?

I was wondering if there is a downside on midi latency when daisy chaining a sound card with an HD?

thejammer's Website

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

I mean if you go out of the computer to the HD and then to the soundcard... is it a possible solution?

thejammer's Website

  • Registered: 2008-01-01
  • Posts: 3,025

Re: FF400 on 1394b audio dropout

Yes, daisy-chaining might be a possible solution. I doubt that the Mac Pro has two separate Firewire lines (you likely wouldn't experience dropouts if it had), so internally the two ports are daisy-chained anyway. Handing the daisy-chaining to the HD might help, so just try it.

You can also try to daisy-chain the HD after the FF400, but of course you are restricted to FW400 speed for the HD then and both devices have to share a FW400 line when they work at the same time. Still better than a non-working solution, though.

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

Thanks. I finally fix the problem. It seems that even the 1394a and 1394b are link together. Driving a full backup of a drive at the same time of having my FF400 playing music in itunes was making the soundcard freaking out.

I have another pci express card with 1394a and usb on it. I just plug my sound card on that one, and put all HD with firewires on the onboard bus. Now it's working like a charm.

Thanks for your help!

thejammer's Website

  • Registered: 2008-01-01
  • Posts: 3,025

Re: FF400 on 1394b audio dropout

That's what I wrote, the 1394a port internally is just a daisy-chained port with another connector.

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

Yes, I understood that, but the mac pro has 2 x 1394a and 2 x 1394b so your explanation doesn't tell me that the two buses are linked together (a and b), and I understand in the way that the 2 ports 1394b are linked together only.

Sorry about that confusion. Anyway, you were right. Thanks for your help!

thejammer's Website

  • Registered: 2008-01-01
  • Posts: 3,025

Re: FF400 on 1394b audio dropout

Hm, the 4 port configuration is interesting. Last time I looked at a Firewire chipset specification it had 3 internal ports (on chip), so either the Mac Pro uses an externally daisy-chained port or it uses a chipset with 4 internal ports. Or maybe the 4 ports are not shared, but the sharing is 2 + 2, but with one pair of FW800 + 400 being on one line?

Does it make any difference which of the four ports you use together?

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

I will test it for sure, it's an interesting subject. Let me do a test tonight and get back to you tomorrow.

thejammer's Website

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

One thing for sure, is that if I plug the HD on 1394b  and the FF400 on 1394a on the back, I get dropouts from the card. Test 1: I'll try to use the 1394a port at the front for the sound card and 1394b at the back for the HD.
Test 2: I'll try to use the 1394a port at the front for the sound card and 1394b at the front for the HD.

This way we should get a clear picture of it.

thejammer's Website

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

I have done a couple of tests... and I am really confused now.

I was able to copy files on the HD and playing with GarageBand and Logic during this time in both tests without drops.

No idea why the ports behind are not working together.

Anyway, I have a stable configuration now.

Thanks.

thejammer's Website

  • From: Montreal, Canada
  • Registered: 2011-06-09
  • Posts: 13

Re: FF400 on 1394b audio dropout

hmmm I'll run other tests, I think that it may be a 3 x 1 configuration. Maybe the 1394b port at the front is isolated. I'll get back.

thejammer's Website