linuxaudio.org

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On Jan 23, 2013 5:13 PM, "Paul Davis"  wrote:

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>

>

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> On Wed, Jan 23, 2013 at 5:10 PM, Len Ovens  wrote:

>>

>>

>> I have been reading what I can on audio interfaces... I am thinking there

>> are very few good ones. I am thinking that some parts of the system are

>> vastly over priced like ADAT and MADI interfaces, both of which seem to

>> cost about 10X (at least) what they should cost... like how come a Gb NIC

>> is well under 0 and MADI PCI(e) card (100Mb) is 0?

>

>

> Gb NIC sales: in the millions

> MADI PCI(e) card sales: low thousands if you are lucky, hundreds if not

>

>

> > For audio quality, it seems FW, USB and ethernet _could_ give better

results if designed right.

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> none of them live "on the bus" the way a PCI card can. all of them are

subject to a separate clock, in addition to the audio sample clock and the

PCI bus clock (which is so high a frequency as to be mostly irrelevant).

Anyway you got to have a breakout box with any decent pcie card.  The noise

in the power supply has to be bad on the pcie bus.  It's better to use a

good external power supply.  So all you really get out of the pcie is the

bus transport to some other processor in a breakout box that runs the audio

clocks adcs and dacs.
My ideal audio interface would run on something like infiniband or 10Gb

cable.  Insane bandwidth.  But 1Gb is good and can have latency in the low

ms.  It's really cheap and flexible.  Endpoints can be 100s of m away if

you can run that much copper.
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On Jan 23, 2013 5:13 PM, "Paul Davis" <paul@linuxaudiosystems.com> wrote:

quoted text
>

>

>

>

> On Wed, Jan 23, 2013 at 5:10 PM, Len Ovens <len@ovenwerks.net> wrote:

>>

>>

>> I have been reading what I can on audio interfaces... I am thinkin=

g there

quoted text
>> are very few good ones. I am thinking that some parts of the syste=

m are

quoted text
>> vastly over priced like ADAT and MADI interfaces, both of which se=

em to

quoted text
>> cost about 10X (at least) what they should cost... like how come a=

 Gb NIC

quoted text
>> is well under 0 and MADI PCI(e) card (100Mb) is 0?

>

>

> Gb NIC sales: in the millions

> MADI PCI(e) card sales: low thousands if you are lucky, hundreds if no=

t

quoted text
>

>

> > For audio quality, it seems FW, USB and ethernet _could_ give bet=

ter results if designed right.

quoted text
>

> none of them live "on the bus" the way a PCI card can. all o=

f them are subject to a separate clock, in addition to the audio sample clo=

ck and the PCI bus clock (which is so high a frequency as to be mostly irre=

levant).

Anyway you got to have a breakout box with any decent pcie card.=A0 The =

noise in the power supply has to be bad on the pcie bus.=A0 It's better=

 to use a good external power supply.=A0 So all you really get out of the p=

cie is the bus transport to some other processor in a breakout box that run=

s the audio clocks adcs and dacs.=A0 
My ideal audio interface would run on something like infiniband or 10Gb =

cable.=A0 Insane bandwidth.=A0 But 1Gb is good and can have latency in the =

low ms.=A0 It's really cheap and flexible.=A0 Endpoints can be 100s of =

m away if you can run that much copper.=A0 
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