Philip Schleihauf phil at
Fri Feb 6 19:30:40 GMT 2009

After doing a bit more research I've found that daisy-chaining two
fireboxes is supposed to be impossible. Presonus' drivers can't do it.
I never would have expected the open-source alternative to provide
more functionality, that's just awesome.

It seems like setting up multiple firepods on windows/mac is very
complicated. I guess you can only use the outputs on one of them or
something.... when I hook up both fireboxes I get all the inputs and
all the outputs. I just plug them in and start jack.

If I can get my hands on a laptop, I'll install UStudio on it and take
it and my firebox to a music store and see if I can chain it with a
firepod. Man, would it be nice to just run a FW cable out from the
control room instead of all those XLRs or a snake, and still have some
ins and outs available right on the desk.

Anyway, getting back on-topic a bit, Juan:

If you are using Ubuntu Studio, you will already have the RT
(realtime) kernel. This will allow you to use much lower latency
settings, without getting x-runs.
In order to actually use RT, you need to make sure that RealTime is
enabled from the "Setup" window in Jack Control.
It should be the very first check box under Parameters.
The other potential causes of x-runs are the frames/period, Sample
Rate, Periods/buffer, and Audio.

For simple sessions, these setting work for me:
Frames/Period: 256
Periods/Buffer: 2

Most of the time I am recording music, which will most likely be
distributed on CD. I use a sample rate of 44100 because that is the
sample rate that CDs use. When I do music for movies, I use 48000,
because that is the sample rate for DVDs. Perhaps someone will correct
me on this, but I think converting from 48000 to 44100 Hz would
actually result in slightly lower quality than something recorded at
Just bear in mind that higher sampling rates mean higher latencies,
and more processing power, which could contribute to x-runs.

Finally, the Audio setting, which by default is at "Duplex", can be
set to "Capture Only" if you are having lots of problems with x-runs.
With this setup, you will not be able to play back audio from the
computer. I don't think resorting to this is ever really needed,
except in cases like my 2001 iBook which refuses to power my FireBOX
unless it's at "Capture Only".

These settings (at 44100 Hz) will produce 11.6 MSec of latency.
That's.... good enough. If the singer needs to hear themselves through
headphones, there will be a barely-noticeable delay. Anything under 10
msec would be better, but that's where I start running into x-runs. If
you don't need to monitor tracks, you can push the latency up to
69.7msec (1024 frames, 3 periods - default JACK settings), and you
should be very safe from x-runs. I use this setting when mixing, and
adding effects after the recording is done.

Presonus products can technically do 0-latency monitoring. They can
route inputs directly to outputs within the actual fire-whatever.
However this is impossible (as far as I know) with linux. It has to be
done from the Presonus software. I tried once to get that software to
work under WINE, to no avail. Anyone have any luck getting 0-latency
on presonus products?

Sorry this message is so long.

Good luck,

Philip Schleihauf
phil at

On Fri, Feb 6, 2009 at 1:12 PM, suemac at <suemac at> wrote:
> From what I've read on this on the windows side, the second pod needs to be
> set to be slave. I also read something about setting them to sync via
> spdif...
> The fact that you've actually done it is promising.
> There are some posts about defining which device is to be first and second.
> Some of this may need to be configged in the pod. THe windows application
> that shipps with them can do this, I'm wondering if the ffado-tools has
> anything that can do the same.
> Mac
> Original Message:
> -----------------
> From: Philip Schleihauf phil at
> Date: Fri, 6 Feb 2009 12:05:51 -0500
> To: ubuntu-studio-users at
> Subject: Re: Presonus
> Hey
> I've got a presonus firebox, which is the little version of the firepod I
> guess.
> When I use the RT kernel I don't get any x-runs, unless I set insane
> parameters on the frames/period and periods/buffer.
> As far as daisy-chaining goes:
> I often daisy-chain it with my friend's firebox. It works very well.
> There's only two problems:
> 1- sometimes when I start JACK they are out of sync from each other by
> the amount of latency that jack is set to. So If jack is at 11.6msec,
> one of them will be at 11.6, but the other one will record at 23.2.
> This problem is totally random. Sometimes it does this and sometimes it
> doesn't.
> 2- The order the connections show up in jack sometimes changes. This
> can be very annoying if jack crashes in a session, and I have to
> restart it; often the order will have switched. Then I have to redo
> all the connections.
> Presonus claims that daisy-chaining firepods works, but they don't say
> that fireboxes can be daisy-chained. I think you'd be ok with the
> firepods.
> Does anyone know if it is possible to daisy-chain a firebox with a
> firepod? That's my dream at this point.
> Philip Schleihauf
> phil at
> On Fri, Feb 6, 2009 at 10:47 AM, suemac at <suemac at>
> wrote:
>>>Original Message:
>>>From: juan pablo juanpablo.santacreu at
>>>Date: Fri, 6 Feb 2009 10:38:24 +0100
>>>To: ubuntu-studio-users at
>>>Subject: Presonus
>> <snip>
>>>I´m new in the list and, i´m very excited with ubuntu studio and my new
>>>presonus firepod.
>>>All seem to work fine. I get some xrun... maybe i still have to adjust
>>>some parameter.
>>>Someone in the list with the presonus firepod??
>>>Some example of garage music recording, mixing and mastering with
>>>ubuntu studio and the presonus?
>> Hi Juan,
>> I have a firepod. I hope to actually daisy chain two of them eventually
> but
>> it appears no one has attempted that in Linux land...
>> I am using UBStudio hardy 64bit, so I have the rt kernel. I found if I got
>> all the latest Jack, ardour, ffado, etc that xruns are very few.
>> Mac
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