Re: [FFADO-user] Hardware Mixing

[Philippe C. <la-...@or...>]

Le lundi 17 décembre 2012 à 14:26 +0100, oth...@gm... a écrit :

> Hi from a future ffado user,
> 

Hi Simon.

>  I have searched the lists and device pages and FAQs but couldn't find an answer to these questions.
> 
>  I am about to purchase a firewire interface, most likely a Saffire Pro 40 as it seems to be reasonably well supported. 

The status of Pro 40 under ffado is the following
    - full support of capture/playback up to 88.2kHz. At 96kHz, playback
streaming does not work for an unknown reason.
    - hardware mixer/router is fully supported via ffado-mixer.
    - hardware monitoring is also fully supported but you will have to
use the "trunk" svn version.
The status is the same for Pro 14 and Pro 24; as mentioned by Stefan,
Pro 24 DSP works as a simple Pro 24 under ffado ("DSP" is not
supported).
Now,  working at 88.2kHz does not seem to be so stable, some users
reporting issues depending on the firewire controller and possibly of
the kernel they use. 

> I would also consider a second hand Presonus Firestudio (26),

This is an old interface; possibly I am mistaking but I didn't see it in
the "configuration" file.
At the opposite, many people use ffado for Firestudio Project and
Firestudio Tube; hardware mixer/router should be fully supported via
ffado-mixer for these devices. Once again, it requires the latest trunk
svn version of ffado.
Firestudio Mobile is reported to work; it does not possess hardware
mixer/router (to my knowledge). 

>  Echo Audiofire Pre8 

I don't know more than what is written on ffado website.

> or even a TC Studio Konnekt 48 

Studio Konnect 48 uses a Dice II chip. To my knowledge it works for
capture and playback, but informations from the manufacturer would be
required for hardware mixer/router support and TC never provided such
infos.


> (at the moment I can get one second hand, without the remote unfortunately, at about the same price as a Pro 40). However these ones seem to be less supported or at least less actively worked on as far as I can tell, is that correct?
> 
>  The main question I have is regarding what various manufacturers call "hardware monitoring" or "DSP mixing" or "on board zero latency mixing" which (I'm not sure but I guess) refer to the same thing. 

"zero" latency refers to something like a tenth of microseconds of
latency; this is obtained by the use of  a digital signal processor
(DSP) inside the device. So the device itself does not induce additional
latency and latency will mostly result from the data exchange between
the device and the PC.
Now, the DSP may be involved for more than only mixing, routing or
monitoring, including for instance reverb effects, equalization and so
on. 
Hardware "monitoring" is quite vague and you have to care with. Now Pro
14 to 40, Firestudio Project and Tube, Konnect 48 use a Dice chip which
include a "zero" latency DSP.

> Is this supported in ffado for any of these devices? Does ffado-mixer only control the audio that actually comes into and out of the computer? Can it also (for example) tell the device to send this input to that output at this level without routing the audio through the computer (for monitoring purposes)?

ffado-mixer deals with the settings of the internal of the device
(mainly, it allows to set up specific registers in the rom of the
device);  what is send into or comes from the firewire ports is
controlled by jack.

> 
>  Sorry if the question seems obvious but I haven't used ffado yet as I don't have a firewire interface. And if this is supported differently on different devices I would like to know before I buy one!
> 
>  Thanks in advance for any assistance,
> 

Regards,

Phil

>  Simon


-- 
Philippe Carriere <la-...@or...>