14 Jan
2007
14 Jan
'07
6:02 p.m.
Folks,
I will be building an audiophile/home theater system soon. I'm starting with
2-channel and want to make my way up to 4 (i don't like center channels).
I'm using my computer as the front end. I'd like to use USB, Firewire or
wireless as my "transmission lines".
As far as multichannel goes, i'd imagine that even if i split audio into front
and back and sent each to a wireless Slim Devices Transporter (
http://www.slimdevices.com/pi_transporter.html) that the two tranporters
would not be in synch.
So, is a firewire device like the Apogee Rosetta 800 a solution? Will a linux
movie player using xine or gstreamer be able to send the correct channels of
the Dolby Digital/DTS to the individual channels on a multi-channel pro
device?
This all assumes that Freebob (the firewire driver) works as advertised.
I realize i can just send a dolby digital/DTS signal to the Transporter and
then on to a pre/pro but that adds another link in the chain.
Thanks all.
14 Jan
14 Jan
6:25 p.m.
On Sun, 2007-01-14 at 15:02 -0700, Bearcat M. Sandor wrote:
So, is a firewire device like the Apogee Rosetta 800 a
solution? Will a linux
movie player using xine or gstreamer be able to send the correct channels of
the Dolby Digital/DTS to the individual channels on a multi-channel pro
device?
This all assumes that Freebob (the firewire driver) works as advertised.
"as advertised"? Freebob is ultimately going to produce an ALSA driver,
but it's not ready (afaik, work hasn't started on it). Freebob currently
is usable with jack-aware applicatios, but those tend to be geared
towards music production, not consumption.
Regarding advertisement:
"Not recommended for beginners or production use." From the FAQ on
freebob.sf.net
Yes, it works for a lot of people. But those people are experts and know
what they are getting into. I STRONGLY recommend getting a preferably
PCI sound card supported by ALSA.
Sampo
15 Jan
15 Jan
2:14 p.m.
Sampo,
Thank you.
On Sunday 14 January 2007 15:24 in an email titled "Re: [linux-audio-user]
Multi-channel audio with a computer front end" Sampo Savolainen wrote:
On Sun, 2007-01-14 at 15:02 -0700, Bearcat M. Sandor
wrote:
So, is a firewire device like the Apogee Rosetta
800 a solution? Will a
linux movie player using xine or gstreamer be able to send the correct
channels of the Dolby Digital/DTS to the individual channels on a
multi-channel pro device?
This all assumes that Freebob (the firewire driver) works as advertised.
"as advertised"? Freebob is ultimately going to produce an ALSA driver,
but it's not ready (afaik, work hasn't started on it). Freebob currently
is usable with jack-aware applicatios, but those tend to be geared
towards music production, not consumption.
Regarding advertisement:
"Not recommended for beginners or production use." From the FAQ on
freebob.sf.net
Yes, it works for a lot of people. But those people are experts and know
what they are getting into. I STRONGLY recommend getting a preferably
PCI sound card supported by ALSA.
Sampo 
11:55 a.m.
New subject: [linux-audio-user] Multi-channel audio with a computer front end
On Sun, 2007-01-14 at 15:02 -0700, Bearcat M. Sandor wrote:
Folks,
I will be building an audiophile/home theater system soon. I'm starting with
2-channel and want to make my way up to 4 (i don't like center channels).
I'm using my computer as the front end. I'd like to use USB, Firewire or
wireless as my "transmission lines".
As far as multichannel goes, i'd imagine that even if i split audio into front
and back and sent each to a wireless Slim Devices Transporter (
http://www.slimdevices.com/pi_transporter.html) that the two tranporters
would not be in synch.
you seem to have this a little backwards, or else i'm not remembering a
key difference between the transporter and its little brother the
squeezebox.
in its primary designed-for mode, you don't send an audio signal stream
to the transporter. the transport fetches audio data from the computer
via networking protocols, and then delivers an audio signal to your
amplification equipment.
it does appear that you can send an audio signal to the transport via
either a TOSlink/RCA/AES connector. presumably you'd do this if you want
to use the A/D's in the transporter. but .... the transport has only
stereo converters and outs, so the only signal you'd be sending it would
be stereo.
in other words, i'm totally confused by your goals.
--p
2:12 p.m.
New subject: [linux-audio-user] Multi-channel audio with a computer front end
On Monday 15 January 2007 08:54 in an email titled "Re: [linux-audio-user]
Multi-channel audio with a computer front end" Paul Davis wrote:
in other words, i'm totally confused by your
goals.
--p
Thanx Paul. Here is what i am trying to do. I want to use my computer as a
front end in a multi-channel system with a little as possible between it and
the amplifiers for purities sake. I do not want D/A conversion inside the PC
as that is noisy and jittery. I do not want to use spdif or toslink as those
are also jittery (or so i understand).
The Slim Devices (squeezebox or Transporter) are fine for stereo but will not
work for multichannel due to latency issues. You can send a digital signal to
a pre/pro from them but that adds a pre/pro in the mix and i'd rather not.
So that leaves me with usb or firewire.
I have seen a few pro audio D/A converters devices that are multi-channel such
as the Apogee rosetta 800
(http://www.apogeedigital.com/products/rosetta800.php). The ones that can do
24/192 (which is also a goal here) are firewire devices. I have also seen
some that are USB based but are 24/96 only. That is not as good, but
acceptable.
Can my system send all the channels to one of these devices via usb or
firewire and have the device break them out and send them to the appropriate
speakers. These devices know nothing about DTS, DD and the like so the
computer would have to determine what sound goes into what channel and send
all that to the device. I know that were i using a mixing like Audacity or
Audour it could be done, but the question is can the media player engines
(gstreamer or xine) do that as well?
If that answer is "no", then i can move the attention down to stereo USB
devices. Since linux can use multiple sound cards i could purchase 3 stereo
USB devices. Could I have Xine or Gstreamer send the front channels to one,
the centers to another and the l/r rears to another? If so, am i going to
run into a problem with timing issues between the 3 devices? Is USB going to
cause such latency problems?
I could send it all out digitally and just let a pre/pro handle it. However,
then i am limited to what the pre/pro understands and i want to play with
things like ambiophonics and such. I'd also like to do a little mixing and
recording and a pre/pro isn't meant for that.
I reailse that using usb/firewire in this way will result in my using digital
attenuation instead of analog. This is not ideal, but could be solved with
passive volume controls on the other end. However, since i am looking at
24-bit and my listening levels are quite low it should not introduce any
limits in the audio resolution.
If i need to explain further i am happy too.
Thank you.
8:41 p.m.
New subject: [linux-audio-user] Multi-channel audio with a computer front end
On Mon, 2007-01-15 at 11:12 -0700, Bearcat M. Sandor wrote:
On Monday 15 January 2007 08:54 in an email titled
"Re: [linux-audio-user]
Multi-channel audio with a computer front end" Paul Davis wrote:
you still seem very confused. or i am. or both.
first of all, D/A conversion associated with the computer does need to
be noisy - there are many devices with external breakout boxes now - and
it does not need to be jittery if you are willing to spend money on good
equipment. i would agree that doing it inside the chassis case is
probably not the best arrangement, but thats not much of an issue these
days.
secondly, s/pdif is not inherently jittery - jitter is determined by the
sample clock, and that can be extremely low jitter or extremely high
jitter depending on where it is coming from (i.e. who makes it). toslink
is not an alternate protocol, its a physical connector+cable. you can
use toslink to transmit S/PDIF or ADAT or a few other things as well.
in other words, i'm totally confused by your
goals.
--p
Thanx Paul. Here is what i am trying to do. I want to use my computer as a
front end in a multi-channel system with a little as possible between it and
the amplifiers for purities sake. I do not want D/A conversion inside the PC
as that is noisy and jittery. I do not want to use spdif or toslink as those
are also jittery (or so i understand).
The Slim Devices (squeezebox or Transporter) are fine for stereo but will not
work for multichannel due to latency issues. You can send a digital signal to
a pre/pro from them but that adds a pre/pro in the mix and i'd rather not.
So that leaves me with usb or firewire. Can my system send all the channels to one of these
devices via usb or
firewire and have the device break them out and send them to the appropriate
speakers.
for example, i run an RME digiface, which has 26 channels in and out.
the i/o box is external to the computer, connected by a 4m firewire
cable (though it doesn't use any standard firewire protocol). the
digiface is digital i/o only, so i then route its i/o to and from a
couple of 8 channel frontier design Tango24 converters which are in turn
connected via a patchbay to the analog part of my setup.
the RME multiface is an alternate breakout box that has D/A converters
built in for 8 channels.
RME solutions have too high a channel count for you, however.
These devices know nothing about DTS, DD and the like
so the
computer would have to determine what sound goes into what channel and send
all that to the device. I know that were i using a mixing like Audacity or
Audour it could be done, but the question is can the media player engines
(gstreamer or xine) do that as well?
if they can emit ac3 encoded audio, it be sent passthru over any s/pdif
connector. if they can't, then you're stuck with a multi-channel signal
stream.
If that answer is "no", then i can move the
attention down to stereo USB
devices. Since linux can use multiple sound cards i could purchase 3 stereo
USB devices. Could I have Xine or Gstreamer send the front channels to one,
the centers to another and the l/r rears to another? If so, am i going to
run into a problem with timing issues between the 3 devices? Is USB going to
cause such latency problems?
any configuration involving more than 1 digital audio device *must*
include a shared sample clock source in order to avoid sync issues. no
exceptions.
then i am limited to what the pre/pro understands and
i want to play with
things like ambiophonics and such. I'd also like to do a little mixing and
recording and a pre/pro isn't meant for that.
pre-amps in the pro-audio sense have no role to play here. by the time
the signal leaves a D/A, its already line level. unless you mean
"preamp" in the home stereo sense, which is basically just a volume
control, source select and optionally tone controls.
i can see no role for a transporter in anything you've described.
what you need is a PCI audio interface with multiple channels and an
external breakout box. if the interface only does digital i/o, then you
need an additional external multichannel D/A box as well.
the transport is a device to use network protocols, either over a
physical ethernet or wifi layer, to move audio data from the computer
disk to the D/A's built into the transporter, or to be resent using
s/pdif via its digital outs. it is a two channel device, and so plays
not role in a multichannel set up.
--p
9:03 p.m.
On 1/15/07, Paul Davis <paul(a)linuxaudiosystems.com> wrote:
<SNIP>
first of all, D/A conversion associated with the computer does need to
be noisy - there are many devices with external breakout boxes now - and
it does not need to be jittery if you are willing to spend money on good
equipment. i would agree that doing it inside the chassis case is
probably not the best arrangement, but thats not much of an issue these
days.
<SNIP>
I agree with everythign PAul said although I *think* he meant to say
"D/A conversion associated with the computer does (NOT) need to be
noisy". D/A converters inside of a computer are a bad idea but mounted
externally in a breakout box they are no different than the same
converters sitting inside a recording studio.
<SNIP>
RME solutions have too high a channel count for you, however.
<Revisiting your original post>
Will a linux
movie player using xine or gstreamer be able to send the correct channels of
the Dolby Digital/DTS to the individual channels on a multi-channel pro
device?
</Revisiting>
I run an RME HDSP 9652. I suspect that's similar to what Paul is
running these days. I have used xine with hdspmixer to mix 5.1 output
into other formats, like stereo. There is no reason you couldn't do
the same mixing 5.1 into 4.1 or some other arrangement that works with
your specialized setup. It worked great for me. xine outputs six
channels of audio. You can do whatever you want wither each channel -
ladspa plugins, combinations routed how you like, etc. It's quite easy
with hdspmixer.
As others have said I would stay away from the FreeBob solutions at
this time, unless you have a stomach for working through whatever
issues you are going to come across. You could do a *Very* nice
high-end home theater system using an HDSP 9636 and a good set of
D/A's. You might look at one of the low-cost (<$250) 8 channel ones
for all the extra channels and use something like a Benchmark DAC1
which has really great sound, albeit a bit pricey but not totally over
the top, for left and right.
Hope this helps,
Mark
11:08 p.m.
I'm replying to both of you Paul and Mark in one email. It's just easier that
way and clearer. Thank you for both of your responses. Now, on to my
clarifications and questions. I apologise for the confused questions, but
i'm well confused. My aim is to use my computer as the front-end and and have
it do all of the DSP for maximum flexibility. I want as few components as
possible between the computer and amps, unless i *have* to use a pre-amp for
extra gain. More clarifications are below.
On 1/15/07, Paul Davis
<paul(a)linuxaudiosystems.com> wrote:
<SNIP>
Actually, i used
to have an RME Hammerfall 9636 it worked very nicely, except
that there are no mixers in it. In fact it was Paul that helped me with the
Alsa config files to keep it going. Thanks Paul! In the years since i've
forgotten all about it. It might be just what i need. Currently, i am using
nvidia on-board sound and i can hear the fans of the PC in my speakers along
with a little buzzing. Horrid :) Granted this is with my ear near the cone,
but any noise adds coloration. I'm looking at purchasing a pair of Gallo
Reference 3.1 and a set or Red Dragon Class D monoblocks all of which are
which are *very* revealing and this noise must go.
first of all, D/A conversion associated with the
computer does need to
be noisy - there are many devices with external breakout boxes now - and
it does not need to be jittery if you are willing to spend money on good
equipment. i would agree that doing it inside the chassis case is
probably not the best arrangement, but thats not much of an issue these
days.
<SNIP>
I agree with everythign PAul said although I *think* he meant to say
"D/A conversion associated with the computer does (NOT) need to be
noisy". D/A converters inside of a computer are a bad idea but mounted
externally in a breakout box they are no different than the same
converters sitting inside a recording studio.
<SNIP>
> RME solutions have too high a channel count for you, however. <Revisiting your original post>
Will a linux
movie player using xine or gstreamer be able to send the correct channels of
the Dolby Digital/DTS to the individual channels on a multi-channel pro
device?
</Revisiting>
I run an RME HDSP 9652. I suspect that's similar to what Paul is
running these days. I have used xine with hdspmixer to mix 5.1 output
into other formats, like stereo. There is no reason you couldn't do
the same mixing 5.1 into 4.1 or some other arrangement that works with
your specialized setup. It worked great for me. xine outputs six
channels of audio. You can do whatever you want wither each channel -
ladspa plugins, combinations routed how you like, etc. It's quite easy
with hdspmixer.
As others have said I would stay away from the FreeBob
solutions at
this time, unless you have a stomach for working through whatever
issues you are going to come across. You could do a *Very* nice
high-end home theater system using an HDSP 9636 and a good set of
D/A's. You might look at one of the low-cost (<$250) 8 channel ones
for all the extra channels and use something like a Benchmark DAC1
which has really great sound, albeit a bit pricey but not totally over
the top, for left and right.
I'm a little confused as to what connection i would use with the hdsp 3696 and
the Benchmark DAC1 to get 24/192 in at least 4 channels.
Yes, thank you. I'm looking for 4 channels actually as i don't like center
channels (left, right, rear right, rear left). 8 channels is fine actually
as i can use the other channels for something. I may use it as as DAW
sometimes or multi-zoning,
Hsdpmixer sounds just like what i have been looking for, but i looked around
for details on it and could find nothing. Is this an app to interface with
the internal mixer of the card or is it the name for the mixer on the card
itself?
I've read in the audiophile press that usb/firewire is more desirable then
spdif because usb/firewire has lower levels of jitter. Of course if the
difference is truly inaudible i don't care.
The less components and cables between the computer and the amps the better
(generally unless you need extra gain provided by a pre-amp). If i were to
use an RME Hammerfall DSP 9632 and go straight into an amplifier (monoblocks)
I would still get all the computer noise as i would be doing D/A inside the
box, right? Of course i could get a fanless video card, power supply and
chipset, but then the case fans might still add noise, not to mention the
electronics itself. Of course this won't work if the gain on the RME is not
high enough (i'd be using the balanced outs). However, i assume i'll get the
Buzz of Doom if my computer powers down and the amps are on.
So if need to send it out to a breakout box. Would this be better done through
adat or spdif? I'm looking for at least 4 channels of 24/192 being delivered
to 4 monoblocks and i thought that neither could do that. If i got 2
Benchmark DAC1s they would not necessarily be in synch right?
I've always liked the RME cards and i just read somewhere that Paul is
actually a RME dealer. I'd be looking to buy a card sometime this summer.
I'll contact you then.
Hope this helps,
Mark
11:55 p.m.
On 1/15/07, Bearcat M. Sandor <HomeTheater(a)feline-soul.com> wrote:
<SNIP>
Optical ADAT. The HDSP 9636 would be the master. There would be two
optical ADAT cables going out, one to each DAC1. You would sync the
DAC1's to the ADAT signals. If you used the HDSP 9652 then you could
use the word clock outputs to sync. Aaron Trumm (www.nquit.com -
another LAU user) is selling an HDSP 9652 used if you want to look at
that.
hdspmixer would create the specific mix you are looking for - quite
easy to do really.
I have no idea whether you can actually doing 192KHz in Linux. 96K is
not a problem.
As others have said I would stay away from the
FreeBob solutions at
this time, unless you have a stomach for working through whatever
issues you are going to come across. You could do a *Very* nice
high-end home theater system using an HDSP 9636 and a good set of
D/A's. You might look at one of the low-cost (<$250) 8 channel ones
for all the extra channels and use something like a Benchmark DAC1
which has really great sound, albeit a bit pricey but not totally over
the top, for left and right.
I'm a little confused as to what connection i would use with the hdsp 3696 and
the Benchmark DAC1 to get 24/192 in at least 4 channels.
Yes, thank you. I'm looking for 4 channels actually as i don't like center
channels (left, right, rear right, rear left). 8 channels is fine actually
as i can use the other channels for something. I may use it as as DAW
sometimes or multi-zoning,
Hsdpmixer sounds just like what i have been looking for, but i looked around
for details on it and could find nothing. Is this an app to interface with
the internal mixer of the card or is it the name for the mixer on the card
itself?
The HDSP 9652 has hardware mixing. hdspmixer is the app that allows
you to control it. It's part of the alsa-tools package.
I've read in the audiophile press that usb/firewire is more desirable then
spdif because usb/firewire has lower levels of jitter. Of course if the
difference is truly inaudible i don't care.
If you truly care about this then get an external word clock generator
from someone like Apogee. However I think starting with an HDSP 9652
and using it's word clock output would be more than acceptable for
studio level quality.
The less components and cables between the computer and the amps the better
(generally unless you need extra gain provided by a pre-amp). If i were to
use an RME Hammerfall DSP 9632 and go straight into an amplifier (monoblocks)
You cannot. The HDSP 9636/9652 has no analog conversion. You must go
HDSP->DAC->Amp.
I drive my studio monitor power amp directly from my 8 channel D/A. No
need for a preamp.
<SNIP>
So if need to send it out to a breakout box. Would this be better done through
adat or spdif? I'm looking for at least 4 channels of 24/192 being delivered
to 4 monoblocks and i thought that neither could do that. If i got 2
Benchmark DAC1s they would not necessarily be in synch right?
Wrong. They must be in sync but they will be since your HDSP would be
the master and the DAC1's would be the slaves.
I've always liked the RME cards and i just read somewhere that Paul is
actually a RME dealer. I'd be looking to buy a card sometime this summer.
I'll contact you then.
Paul is a nice guy who can always use a sale I suppose.
Cheers,
Mark
16 Jan
16 Jan
4:28 a.m.
Mark,
Thank you. This is not only looking very hopeful, it's looking affordable (at
least in an industry where $10k speakers systems are "reasonably priced" :) )
Question below.
On Monday 15 January 2007 20:55 in an email titled "Re: [linux-audio-user]
Multi-channel audio with a computer front end" Mark Knecht wrote:
Optical ADAT. The HDSP 9636 would be the master. There
would be two
optical ADAT cables going out, one to each DAC1. You would sync the
DAC1's to the ADAT signals. If you used the HDSP 9652 then you could
use the word clock outputs to sync. Aaron Trumm (www.nquit.com -
another LAU user) is selling an HDSP 9652 used if you want to look at
that.
hdspmixer would create the specific mix you are looking for - quite
easy to do really.
I see the clock outputs on the HDSP9652, but i don't see the
clocks inputs on
the Benchmark dac1 or the RME ADI-2. What am i not understanding?
I'm looking at them here: http://www.sweetwater.com/store/detail/ADI2/ and
here: http://www.sweetwater.com/store/detail/DAC1/
The specs of the RME ADI-2 look fantastic. It can even be powered by batteries
which is ideal for a truly silent music background and dynamics and it also
accepts 192k. Then again the Benchmark looks better :)
Thanks again.
29 Jan
29 Jan
2:21 p.m.
New subject: [linux-audio-user] Multi-channel audio with a computerfront end
D/A conversion inside the PC does not always mean jitter and noise. The
LynxTwo series of PCI cards has very little noise and some of the best
sounding DACs I've heard. Unfortunately, the LynxTwo series is not
supported by Alsa, only OSS.
Alan
Thanx Paul. Here is what i am trying to do. I want to
use my
computer as a
front end in a multi-channel system with a little as possible
between it and
the amplifiers for purities sake. I do not want D/A conversion
inside the PC
as that is noisy and jittery. I do not want to use spdif or toslink
as those
are also jittery (or so i understand).
2:34 p.m.
New subject: [linux-audio-user] Multi-channel audio with a computerfront end
======= On Monday 29 January 2007, aljordan(a)maine.rr.com wrote: =======
D/A conversion inside the PC does not always mean
jitter and noise. The
LynxTwo series of PCI cards has very little noise and some of the best
sounding DACs I've heard. Unfortunately, the LynxTwo series is not
supported by Alsa, only OSS.
Alan
Alan,
Have you any hrefs to illustrate the words: "D/A conversion inside the PC does not
always mean jitter ...". I'm very interested in facts about jitter - both
"inside"
sound card (that is to say at card's DAC input) and at output SPDIF stream.
Andrew
4:29 p.m.
New subject: [linux-audio-user] Multi-channel audio with a computerfront end
Allan,
Thank you. I think what i am going to do is to pick up a RME Hammerfall
HDSP 96/52 and a Apogee Rosetta 8000. This way, i can get multi-channel
and mixing capabilities up to 96kz. I understand that the RME DSP 9636
does 192khz which is more desirable, but it will not output 192khz
digitally other then spdif (stereo only).
Bearcat M. Sandor
D/A conversion inside the PC does not always mean
jitter and noise. The
LynxTwo series of PCI cards has very little noise and some of the best
sounding DACs I've heard. Unfortunately, the LynxTwo series is not
supported by Alsa, only OSS.
Alan
Thanx Paul. Here is what i am trying to do. I
want to use my
computer as a
front end in a multi-channel system with a little as possible
between it and
the amplifiers for purities sake. I do not want D/A conversion
inside the PC
as that is noisy and jittery. I do not want to use spdif or toslink
as those
are also jittery (or so i understand).
19 Jan
19 Jan
10:01 a.m.
Bearcat M. Sandor wrote:
So, is a firewire device like the Apogee Rosetta 800 a solution? Will a linux
movie player using xine or gstreamer be able to send the correct channels of
the Dolby Digital/DTS to the individual channels on a multi-channel pro
device?
This all assumes that Freebob (the firewire driver) works as advertised.
I realize i can just send a dolby digital/DTS signal to the Transporter and
then on to a pre/pro but that adds another link in the chain.
Note that the 'Advertised' functionality of the current freebob driver
does not contain AC3/DTS pass through.
Pieter
FreeBoB developer
5:26 p.m.
Thanks Pieter. I think i've found a solution that does not involve
freebob, but i look forward to further advancements in it.
Bearcat
Bearcat M. Sandor wrote:
So, is a firewire device like the Apogee Rosetta 800 a solution? Will a
linux
movie player using xine or gstreamer be able to send the correct
channels of
the Dolby Digital/DTS to the individual channels on a multi-channel pro
device?
This all assumes that Freebob (the firewire driver) works as advertised.
I realize i can just send a dolby digital/DTS signal to the Transporter
and
then on to a pre/pro but that adds another link in the chain.
Note that the 'Advertised' functionality of the current freebob driver
does not contain AC3/DTS pass through.
Pieter
FreeBoB developer
6307
days inactive
6322
days old
linux-audio-user@lists.linuxaudio.org
14 comments
7 participants
participants (7)
-
aljordan＠maine.rr.com -
Andrew Gaydenko -
Bearcat M. Sandor -
Mark Knecht -
Paul Davis -
Pieter Palmers -
Sampo Savolainen