Does anyone have anything other than anecdotal or theoretical evidence of
the limits of USB Audio?

Here's my analysis but I've yet to do a full test.

For 16 bit, 44k audio:

(((16 x 44100) / 1024) / 8) x = 86KB / Second (mono)

For USB (12mBit/Sec)

((12 * 1024) / 8) = 1536KB / Second

Maximum audio mono:

1536KB / 86KB = 17 tracks mono

Maximum audio stereo

17 / 2 = 8 stereo tracks



--
http://www.jackzucker.com

For 16 bit, 44k audio:

(((16 x 44100) / 1024) / 8) = 86KB / Second (mono)

For USB (12mBit/Sec)

((12 * 1024) / 8) = 1536KB / Second

Maximum audio mono:

1536KB / 86KB = 17 tracks mono

Maximum audio stereo

17 / 2 = 8 stereo tracks


I just thought about this some more (duh...)

My M-Audio USB Duo handles 2 mono inputs and 2 mono outputs. Therefore, the
maximum I/O that would be going over USB would be:

4*86KB/Second

Or...

(((16 x 44100) / 1024) / 8) * 4

or

345k

which is less than 1/4th the total USB bandwidth. The real limitation will
be the processing power of cakewalk which has to combine the audio and midi
tracks, apply it's virtual effects algorithms and apply them into a stereo
mix to send to the USB audio device for playback.

Jaz

I had an M-Audio Quattro (4 in & 4 out) for awhile and had serious problems
with it. If I wanted to record at 96 khz, I could only record two tracks at
once. If I pushed it down to 44.1 khz, I could theoretically record four
tracks. However, whenever I tried to record two tracks, I'd get about one
minute in and get a dropout. Windows would then pop up a window saying I
used all of the USB bandwidth and it was shutting down the hardware.


"Jack A. Zucker" wrote in message
. net...
For 16 bit, 44k audio:

(((16 x 44100) / 1024) / 8) = 86KB / Second (mono)

For USB (12mBit/Sec)

((12 * 1024) / 8) = 1536KB / Second

Maximum audio mono:

1536KB / 86KB = 17 tracks mono

Maximum audio stereo

17 / 2 = 8 stereo tracks


I just thought about this some more (duh...)

My M-Audio USB Duo handles 2 mono inputs and 2 mono outputs. Therefore,
the
maximum I/O that would be going over USB would be:

4*86KB/Second

Or...

(((16 x 44100) / 1024) / 8) * 4

or

345k

which is less than 1/4th the total USB bandwidth. The real limitation will
be the processing power of cakewalk which has to combine the audio and
midi
tracks, apply it's virtual effects algorithms and apply them into a stereo
mix to send to the USB audio device for playback.

Jaz

"Boardin' Fool" wrote in message


I had an M-Audio Quattro (4 in & 4 out) for awhile and had serious
problems with it. If I wanted to record at 96 khz, I could only
record two tracks at once. If I pushed it down to 44.1 khz, I could
theoretically record four tracks. However, whenever I tried to
record two tracks, I'd get about one minute in and get a dropout.
Windows would then pop up a window saying I used all of the USB
bandwidth and it was shutting down the hardware.


The point is that few computer interfaces transfer data at anything like
their maximum bitrate. In the case of USB, we're talking a highly complex
protocol with lots of overhead.

2 * 96000 * 8 = 1,536,000 bps which is only a tiny fraction of USB's
maximum bitrate of 12 megabits per second.

So much for USB 1.1 and multichannel audio.

There seems to be a lot more *life* in USB 2.0. I know that for CDs and hard
drives, it rocks!

There still aren't a lot of USB 2.0 interfaces. AFAIK the Roland UA-1000 is
the only really interesting one that seems to be available for immediate
delivery.

No,

The point is that USB 1 has plenty of bandwidth for 44k audio with 2
channels in and 2 channels out which is what my posting was about.

"Arny Krueger" wrote in message
...
"Boardin' Fool" wrote in message


I had an M-Audio Quattro (4 in & 4 out) for awhile and had serious
problems with it. If I wanted to record at 96 khz, I could only
record two tracks at once. If I pushed it down to 44.1 khz, I could
theoretically record four tracks. However, whenever I tried to
record two tracks, I'd get about one minute in and get a dropout.
Windows would then pop up a window saying I used all of the USB
bandwidth and it was shutting down the hardware.


The point is that few computer interfaces transfer data at anything like
their maximum bitrate. In the case of USB, we're talking a highly complex
protocol with lots of overhead.

2 * 96000 * 8 = 1,536,000 bps which is only a tiny fraction of USB's
maximum bitrate of 12 megabits per second.

So much for USB 1.1 and multichannel audio.

There seems to be a lot more *life* in USB 2.0. I know that for CDs and
hard
drives, it rocks!

There still aren't a lot of USB 2.0 interfaces. AFAIK the Roland UA-1000
is
the only really interesting one that seems to be available for immediate
delivery.

On modern CPU's this is not where the bottleneck is. Mixing tracks is no
sweat for a CPU, even modest one's (like my 866 p3 can handle well over 32
tracks and still mix them and apply effects with no problem. Get a newer
machine and you can add a good amount of virtual synths to those tracks. USB
sucks, really bad. It was never intended for serious audio use. It's a
miracle that they could even get it to be somewhat practical at all.


which is less than 1/4th the total USB bandwidth. The real limitation will
be the processing power of cakewalk which has to combine the audio and
midi
tracks, apply it's virtual effects algorithms and apply them into a stereo
mix to send to the USB audio device for playback.

Jaz

"Romeo Rondeau" wrote in message
...
USB
sucks, really bad.

Is that a technical term?!? Everyone keeps saying that, yet 4 tracks of 44k
audio is less than 1/4th the total bandwidth of USB1. Why will that not
work. Please explain.

Jaz

"Jack A. Zucker" wrote in message
news
No,

The point is that USB 1 has plenty of bandwidth for 44k audio with 2
channels in and 2 channels out which is what my posting was about.


It's pretty good for stereo audio - but not much else, media wise. This
mostly has to do with the way usb transfers information - only half the time
is data actually transfered. The other half is spent recieving and issuing
requests. Also, a huge chunk of the bandwidth is consumed by data buffers.

You don't have as much problem with accurate file transfers because you can
put a great big cache in software on the host side. If you try that with
audio, there goes your 'low-latency' out the windows.

USB only gets lamer when you start to add devices - say a 2x2 audio device
and a USB midi controller. Each device uses half the bandwidth, even though
the controller would need next to nothing.

Well, that's why it's a low-speed 'serial bus'. It's not supposed to do
anything fast, really - it was desinged with dial-up modems in mind. That's
why the 'usb vs. firewire' thing was always ridiculous, 'apples and oranges'
as they say. It's good that we don't have to choose.

Like I said, it's fine for stereo overdubs.

jb

The *very* best USB host controller stacks (device driver on the host side)
seem to be capable of supporting only about 50% of the theoretical USB
bandwidth. A faster machine helps, but not as much as you would think.
ISO transfers *should* do better, but...
Cheers,
Randy Hyde

"Jack A. Zucker" wrote in message . net...
Does anyone have anything other than anecdotal or theoretical evidence of
the limits of USB Audio?

Here's my analysis but I've yet to do a full test.

For 16 bit, 44k audio:

(((16 x 44100) / 1024) / 8) x = 86KB / Second (mono)

For USB (12mBit/Sec)

((12 * 1024) / 8) = 1536KB / Second

Maximum audio mono:

1536KB / 86KB = 17 tracks mono

Maximum audio stereo

17 / 2 = 8 stereo tracks



--
http://www.jackzucker.com

"Jack A. Zucker" wrote in message . net...
"Romeo Rondeau" wrote in message
...
USB
sucks, really bad.

Is that a technical term?!? Everyone keeps saying that, yet 4 tracks of 44k
audio is less than 1/4th the total bandwidth of USB1. Why will that not
work. Please explain.

Because the host controller software, that moves those packets
around in memory and puts them on/off the bus, stinks.

Microsoft's stacks are especially guilty of this.
The best I've seen, on the average, is about 50% bus utilitization.
You can put together some special tests that do a little bit better,
but in the real world you don't get much better than about 50%
bandwidth.

As memory speeds increase, you should do better.

Now USB 2.0 High-Speed should do better.
Cheers,
Randy Hyde

"Jack A. Zucker" wrote in message
. net...
"Romeo Rondeau" wrote in message
...
USB
sucks, really bad.

Is that a technical term?!? Everyone keeps saying that, yet 4 tracks of
44k
audio is less than 1/4th the total bandwidth of USB1. Why will that not
work. Please explain.


Because a bunch of extra bandwidth is burned up with all the other stuff
that needs to squirt down the wire to keep USB talking.

geoff

I use the quattro on an Toshiba laptop, and since i upgraded my XP home
edition it has done exactly what it is supposed to.
Works great for me

/Per
"Boardin' Fool" skrev i meddelandet
...
I had an M-Audio Quattro (4 in & 4 out) for awhile and had serious
problems
with it. If I wanted to record at 96 khz, I could only record two tracks
at
once. If I pushed it down to 44.1 khz, I could theoretically record four
tracks. However, whenever I tried to record two tracks, I'd get about one
minute in and get a dropout. Windows would then pop up a window saying I
used all of the USB bandwidth and it was shutting down the hardware.


"Jack A. Zucker" wrote in message
. net...
For 16 bit, 44k audio:

(((16 x 44100) / 1024) / 8) = 86KB / Second (mono)

For USB (12mBit/Sec)

((12 * 1024) / 8) = 1536KB / Second

Maximum audio mono:

1536KB / 86KB = 17 tracks mono

Maximum audio stereo

17 / 2 = 8 stereo tracks


I just thought about this some more (duh...)

My M-Audio USB Duo handles 2 mono inputs and 2 mono outputs. Therefore,
the
maximum I/O that would be going over USB would be:

4*86KB/Second

Or...

(((16 x 44100) / 1024) / 8) * 4

or

345k

which is less than 1/4th the total USB bandwidth. The real limitation
will
be the processing power of cakewalk which has to combine the audio and
midi
tracks, apply it's virtual effects algorithms and apply them into a
stereo
mix to send to the USB audio device for playback.

Jaz

"Geoff Wood" -nospam wrote in message
...
Because a bunch of extra bandwidth is burned up with all the other stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take up
over 75% of the bandwidth?

"Jack A. Zucker" wrote in message
. net

"Geoff Wood" -nospam wrote in message
...

Because a bunch of extra bandwidth is burned up with all the other
stuff that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information
take up over 75% of the bandwidth?

The proof of the theory lies in the lab work, right?

How many tracks can a USB 1.1 interface handle with accuracy and reliability
equal to that of a PCI, Firewire, or USB 2.0 interface?

In another post you claimed:

"The real limitation will
be the processing power of cakewalk which has to combine the audio and midi
tracks, apply it's virtual effects algorithms and apply them into a stereo
mix to send to the USB audio device for playback."

So, do the experiment in a program with low CPU overhead on a system with
CPU power to burn.

Hint: the hidden agenda with audio interfaces is that not only do they
require bandwidth, they require bandwidth when they need it, not a few
seconds later. The obvious end run is buffering, but that can increase
latency.

"Jack A. Zucker" wrote:

"Geoff Wood" -nospam wrote in message
...
Because a bunch of extra bandwidth is burned up with all the other stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take up
over 75% of the bandwidth?

Half, anyway. It's a bus, and there have to be delays between packets.
The drivers on the host computer probabaly suck, too. USB was
designed for keyboards and mice, and to replace serial ports.

For (shared) Ethernet, the recommendation is to start thinking about upgrading
when it gets to 40% utilization. A similar dynamic is in effect here.

--
Les Cargill

"Arny Krueger" wrote in message
...
The proof of the theory lies in the lab work, right?

Right - Certainly not in technical terms such as "USB Sucks!". :-)

How many tracks can a USB 1.1 interface handle with accuracy and
reliability
equal to that of a PCI, Firewire, or USB 2.0 interface?

I don't know because I don't have a PCI, Firewire or USB 2 audio interface
to compare it with. Furthermore in theory, it looks like the USB 1 solution
will have more than enough bandwidth to handle 8-12 tracks but I'm planning
on doing a test this week to find out.

With absolutely no optimization of my notebook or win xp pro, I recorded 5
simultaneous audio tracks and had absolutely no glitches.

http://www.jackzucker.com/JazGuitar/...3/ex1blues.mp3

Unfortunately, the recording software that came with the USB Duo is horrible
so I'm awaiting the arrival of Sonar to do a more thorough test.


In another post you claimed:

"The real limitation will
be the processing power of cakewalk which has to combine the audio and
midi
tracks, apply it's virtual effects algorithms and apply them into a stereo
mix to send to the USB audio device for playback."

So, do the experiment in a program with low CPU overhead on a system with
CPU power to burn.

Hint: the hidden agenda with audio interfaces is that not only do they
require bandwidth, they require bandwidth when they need it, not a few
seconds later. The obvious end run is buffering, but that can increase
latency.

"Les Cargill" wrote in message
...
"Jack A. Zucker" wrote:

"Geoff Wood" -nospam wrote in message
...
Because a bunch of extra bandwidth is burned up with all the other
stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take
up
over 75% of the bandwidth?

Half, anyway. It's a bus, and there have to be delays between packets.
The drivers on the host computer probabaly suck, too. USB was
designed for keyboards and mice, and to replace serial ports.

For (shared) Ethernet, the recommendation is to start thinking about
upgrading
when it gets to 40% utilization. A similar dynamic is in effect here.

That's still well under what this audio interface will be reading or writing
to the USB. More like 22%.

Remember, it'll never be seeing more than 2 input and 2 output channels.

"Jack A. Zucker" wrote:

"Les Cargill" wrote in message
...
"Jack A. Zucker" wrote:

"Geoff Wood" -nospam wrote in message
...
Because a bunch of extra bandwidth is burned up with all the other
stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take
up
over 75% of the bandwidth?

Half, anyway. It's a bus, and there have to be delays between packets.
The drivers on the host computer probabaly suck, too. USB was
designed for keyboards and mice, and to replace serial ports.

For (shared) Ethernet, the recommendation is to start thinking about
upgrading
when it gets to 40% utilization. A similar dynamic is in effect here.

That's still well under what this audio interface will be reading or writing
to the USB. More like 22%.

Remember, it'll never be seeing more than 2 input and 2 output channels.

I don't have specific models for specific traffic loads for
specific devices, so I dunno. I was more addressing the "Come
on" part of your post.

I vaguely remember discussions where 4 in, 4 out was pretty
much living dangerously over USB. I'd be guessing, but
40% is probably about where it starts to get unreliable. 4 in
4 out seems to be about that limit, if we all did the
math right.

So far as I know, lots of people use 2-in/2-out with USB all
the time. You get an Arkansas Guarantee with that - if it
breaks in half, you get to keep both halves.

--
Les Cargill

wrote...
"Geoff Wood" -nospam wrote in message
Because a bunch of extra bandwidth is burned up with all the other stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take up
over 75% of the bandwidth?

coughAppletalkcough

--
Exporting jobs is treason.

Clark '04

"Jack A. Zucker" wrote in message
. net
"Arny Krueger" wrote in message
...

The proof of the theory lies in the lab work, right?

Right - Certainly not in technical terms such as "USB Sucks!". :-)

Put yourself in my shoes - the order of the day is 8-16 channels of 24/44.
USB 2.0 or Firewire sure looks good!

How many tracks can a USB 1.1 interface handle with accuracy and
reliability equal to that of a PCI, Firewire, or USB 2.0 interface?

I don't know because I don't have a PCI, Firewire or USB 2 audio
interface to compare it with.

AFAIK, any of them are cool with 8-16 channels of 24/44, or more.

Furthermore in theory, it looks like
the USB 1 solution will have more than enough bandwidth to handle
8-12 tracks but I'm planning on doing a test this week to find out.

With absolutely no optimization of my notebook or win xp pro, I
recorded 5 simultaneous audio tracks and had absolutely no glitches.

http://www.jackzucker.com/JazGuitar/...3/ex1blues.mp3

That's all fine and good, but if you really want the best shot at hearing an
audio interface fall apart, 100 Hz sine waves are IME hard to beat. The
problem is that a lot of really nice music has plenty of tics and pops of
its own.

Unfortunately, the recording software that came with the USB Duo is
horrible so I'm awaiting the arrival of Sonar to do a more thorough
test.

In a previous post you said that you could record and play 2 tracks at the
same time. That's 4 concurrent tracks or about 25% of the maximum data rate
of USB 1.1.

Now, you've upped that to 5 tracks recording (no playback claimed) which is
31% or so of the maximum data rate of USB 1.1. Again, that's all fine and
good, but its not exactly leaping tall buildings with a single bound.

I'm genuinely interested in how far you can go, and wish you the best of
luck in getting there as easily and happily as possible.

I'm not sure that Sonar is the best choice, but maybe it will work out just
fine.

But, if things don't go your way with Sonar, remember that N-Track is as
close as a download and the plastic equivalent of a bit more than a couple
of $20 bills.

Keep us informed!

I thought the Duo had only two ins and two outs. If that's correct, then
your five tracks were all from the same two inputs? If that is the case,
then you aren't actually increasing the amount of bandwidth used by the USB
device. Your software would be the one doubling the inputs to different
tracks in the software.


"Jack A. Zucker" wrote in message
. net...
"Arny Krueger" wrote in message
...
The proof of the theory lies in the lab work, right?

Right - Certainly not in technical terms such as "USB Sucks!". :-)

How many tracks can a USB 1.1 interface handle with accuracy and
reliability
equal to that of a PCI, Firewire, or USB 2.0 interface?

I don't know because I don't have a PCI, Firewire or USB 2 audio interface
to compare it with. Furthermore in theory, it looks like the USB 1
solution
will have more than enough bandwidth to handle 8-12 tracks but I'm
planning
on doing a test this week to find out.

With absolutely no optimization of my notebook or win xp pro, I recorded 5
simultaneous audio tracks and had absolutely no glitches.

http://www.jackzucker.com/JazGuitar/...3/ex1blues.mp3

Unfortunately, the recording software that came with the USB Duo is
horrible
so I'm awaiting the arrival of Sonar to do a more thorough test.


In another post you claimed:

"The real limitation will
be the processing power of cakewalk which has to combine the audio and
midi
tracks, apply it's virtual effects algorithms and apply them into a
stereo
mix to send to the USB audio device for playback."

So, do the experiment in a program with low CPU overhead on a system
with
CPU power to burn.

Hint: the hidden agenda with audio interfaces is that not only do they
require bandwidth, they require bandwidth when they need it, not a few
seconds later. The obvious end run is buffering, but that can increase
latency.

"Richard" wrote in message
.. .
wrote...
"Geoff Wood" -nospam wrote in message
Because a bunch of extra bandwidth is burned up with all the other
stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take
up
over 75% of the bandwidth?

coughAppletalkcough


Rows of five inch screens waiting... and waiting...

jb

What USB audio interface has 12 channels? None that I know of. Why don't you
buy an RME and a small digital board and record and playback 24 tracks with
24 outputs all day long with no problems instead of speculating on what USB
can and can't do?

I don't know because I don't have a PCI, Firewire or USB 2 audio interface
to compare it with. Furthermore in theory, it looks like the USB 1
solution
will have more than enough bandwidth to handle 8-12 tracks but I'm
planning
on doing a test this week to find out.

Then your track count has nothing to do with your interface. What is to be
taken into account is the physical number of inputs and outputs and the
bandwidth requirements of that, not the track count. The computer doesn't
send every track to the interface, just the buss outputs.


Remember, it'll never be seeing more than 2 input and 2 output channels.

coughNot releventcough


coughAppletalkcough

--
Exporting jobs is treason.

Clark '04

wrote...
coughNot releventcough

coughObtain a sense of humorcough

--
Clark '04

"Richard" wrote in message
.. .


wrote...
coughNot releventcough

coughObtain a sense of humorcough



DAMN, somebody get these guys a drink of water!

"Boardin' Fool" wrote in message
...
I thought the Duo had only two ins and two outs. If that's correct, then
your five tracks were all from the same two inputs? If that is the case,
then you aren't actually increasing the amount of bandwidth used by the
USB
device. Your software would be the one doubling the inputs to different
tracks in the software.

That's correct and that's what I said initially when I said the max
bandwidth I'd ever consume on the bus would be 345k...

Go back and read my other posts and you'll see that I said exactly that.

"Arny Krueger" wrote in message
...
In a previous post you said that you could record and play 2 tracks at the
same time. That's 4 concurrent tracks or about 25% of the maximum data
rate
of USB 1.1.

Now, you've upped that to 5 tracks recording (no playback claimed) which
is
31% or so of the maximum data rate of USB 1.1. Again, that's all fine and
good, but its not exactly leaping tall buildings with a single bound.

I think I said several times that with 2 ins and 2 outs the max I can ever
have on the USB bus is 345k (4 tracks). The 5 tracks I was referring to were
in the software, not on the USB bus. I realize those are 2 different
bandwidth paths.

I'm not sure that Sonar is the best choice, but maybe it will work out
just
fine.

Just got it today. So far so good. Truthfully, I'd have opted for Cubase if
I was starting from scratch but I already had Cakewalk Pro Audio 9 and it
was "only" $150 to upgrade.

But, if things don't go your way with Sonar, remember that N-Track is as
close as a download and the plastic equivalent of a bit more than a
couple
of $20 bills.


Really?!? Thanks, I'll check it out.

You're right (of course), I just got a little mixed up in the posts. I
ended up getting rid of my USB devices and going with a Echo Layla. A
friend of mine was upgrading from that to a Pro Tools 002R system, so he
sold it to me cheap ($225). If it works for you, that's great. It just
didn't work for me. As for the actual specs of USB, I've never really
looked them up.



"Jack A. Zucker" wrote in message
. net...
"Boardin' Fool" wrote in message
...
I thought the Duo had only two ins and two outs. If that's correct,
then
your five tracks were all from the same two inputs? If that is the
case,
then you aren't actually increasing the amount of bandwidth used by the
USB
device. Your software would be the one doubling the inputs to different
tracks in the software.

That's correct and that's what I said initially when I said the max
bandwidth I'd ever consume on the bus would be 345k...

Go back and read my other posts and you'll see that I said exactly that.

"Jack A. Zucker" wrote in message
. net...
"Geoff Wood" -nospam wrote in message
...
Because a bunch of extra bandwidth is burned up with all the other stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take
up
over 75% of the bandwidth?


That plus other inefficiencies, yes.

M-Audio clearly state that my Transit USB will do 2 in /2 out at 24/48K, but
is limited to one-way only at 24/96, totally due to USB capbilies. Do the
math yourself....

geoff

"Geoff Wood" -nospam wrote in message
...
M-Audio clearly state that my Transit USB will do 2 in /2 out at 24/48K,
but
is limited to one-way only at 24/96, totally due to USB capbilies. Do the
math yourself....

I already did. Sounds too much like Reiki and aromatherapy to me. Lots of
conjecture and guess-work and faith. I'll try it and let you guys know how I
fare. Fortunately, I have 25 days of my 30 day return policy left. I hate
spending another $175 to get the M-Audio Firewire 410 if I don't really need
it. If I can get my laptop to reliably do 2 in/2 out at 44k, that'll be
fine.

"Boardin' Fool" wrote in message
...
You're right (of course), I just got a little mixed up in the posts. I
ended up getting rid of my USB devices and going with a Echo Layla. A

I'd love to have that but it's more than my budget will allow - Particularly
after paying for my recent spinal surgery!

friend of mine was upgrading from that to a Pro Tools 002R system, so he
sold it to me cheap ($225). If it works for you, that's great. It just
didn't work for me.

Great deal! :-)

As for the actual specs of USB, I've never really
looked them up.

Thanks for the info. I appreciate the time.

"Richard" wrote in message


Exporting jobs is treason.

It's the intersection of capitalism and technological progress.

Oh, so now I see it's crossposted amomg not just two, but THREE
groups...

In alt.music.4-track,rec.audio.pro,rec.music.makers.guitar, "MikeK"
wrote:


"Richard" wrote in message
. ..


wrote...
coughNot releventcough

coughObtain a sense of humorcough



DAMN, somebody get these guys a drink of water!

They remind me how glad I am I quit smoking.

Just a follow up.

So far in 3-4 days of working with the M-Audio USB Duo, I'm not getting any
USB glitches. Maybe USB doesn't suck as bad as some folks thing?!?

OTOH, maybe I'll be bitchin' and moanin' in a couple weeks about how awful
it is. However, for the moment it appears to do what it says it'll do.

Jaz

"Geoff Wood" -nospam wrote in message
...

"Jack A. Zucker" wrote in message
. net...
"Geoff Wood" -nospam wrote in message
...
Because a bunch of extra bandwidth is burned up with all the other
stuff
that needs to squirt down the wire to keep USB talking.

Come on....You're telling me protocol and header packet information take
up
over 75% of the bandwidth?


That plus other inefficiencies, yes.

M-Audio clearly state that my Transit USB will do 2 in /2 out at 24/48K,
but
is limited to one-way only at 24/96, totally due to USB capbilies. Do the
math yourself....

geoff

When your needs exceed the bandwidth, you will :-) Nobody said that USB
interfaces won't do what they claim, just that they don't claim to do much
because they don't do much. When your need for inputs grows (and it will),
you'll have to buy a non-USB interface and get rid of your old one. If
that's not a problem with you, knock yourself out :-)

So far in 3-4 days of working with the M-Audio USB Duo, I'm not getting
any
USB glitches. Maybe USB doesn't suck as bad as some folks thing?!?

OTOH, maybe I'll be bitchin' and moanin' in a couple weeks about how awful
it is. However, for the moment it appears to do what it says it'll do.

"Romeo Rondeau" wrote in message
...
Nobody said that USB
interfaces won't do what they claim

Actually, most folks said exactly that.

, just that they don't claim to do much
because they don't do much. When your need for inputs grows (and it will),
you'll have to buy a non-USB interface and get rid of your old one. If

Not sure I'll ever need more than 2 inputs though. For live recording, I
prefer a simple stereo mic setup and for studio stuff and being a jazz
musician, I prefer to just do a complete take through the stereo inputs
using a mixer if necessary to mix the band down to stereo before it hits the
interface.

If I ever need more than that, I'll give the current setup to my kid. At
$229, it's not like I had to mortgage the house to get it.

Jaz

In alt.music.4-track,rec.audio.pro,rec.music.makers.guitar, "Jack A.
Zucker" wrote:

"Romeo Rondeau" wrote in message
...
Nobody said that USB
interfaces won't do what they claim

Actually, most folks said exactly that.

, just that they don't claim to do much
because they don't do much. When your need for inputs grows (and it will),
you'll have to buy a non-USB interface and get rid of your old one. If

Not sure I'll ever need more than 2 inputs though. For live recording, I
prefer a simple stereo mic setup and for studio stuff and being a jazz
musician, I prefer to just do a complete take through the stereo inputs
using a mixer if necessary to mix the band down to stereo before it hits the
interface.

Apparently the USB interface doesn't have much 'bandwidth headroom'
- if you install more software on this machine, it may 'break' your
interface. An audio editor is probably okay, but anything that
installs a bootup program (such as 'hplamp' to turn off a scanner lamp
after a few minutes, or especially any virus scanner), will take up
'background' processing time, and the processor may not get back to
the USB driver before a buffer overruns.
Problems occurr because audio recording is one of the few real-time
tasks on personal computers. When a computer runs more background
tasks, it doesn't 'break' most programs, they just run noticably
slower, but such tasks can easily break audio recording.
A friend said he was recording LP's (using the built-in soundcard),
but was having problems (clicks apparently from buffer overruns) on
his 350MHz system. I've successfully recorded on a 200MHz machine, so
I knew it was possible for his system to run fine. I told him to look
at what's going on at bootup and what background tasks might be
running that would use up processor resources. He later said his virus
scanner and several other tasks had been running, and when he removed
them he had no problem.
I suspect this is the main problem people have with USB audio
interfaces, and not everyone knows enough to be able to diagnose and
fix it. No one needs a virus checker running while recording sound,
and if you happen to capture some infectious music, the virus checker
won't get it anyway.

If I ever need more than that, I'll give the current setup to my kid. At
$229, it's not like I had to mortgage the house to get it.

Jaz

"Ben Bradley" wrote in message
...
Apparently the USB interface doesn't have much 'bandwidth headroom'
- if you install more software on this machine, it may 'break' your
interface. An audio editor is probably okay, but anything that
installs a bootup program (such as 'hplamp' to turn off a scanner lamp
after a few minutes, or especially any virus scanner), will take up
'background' processing time, and the processor may not get back to
the USB driver before a buffer overruns.

But that has nothing to do with USB bandwidth. In those cases, firewire or
USB2 would have the same issues. When you're talking about the operating
system buffering up queues and latency of serially processing background
tasks, the speed of the bus is no longer the bottleneck.

running that would use up processor resources. He later said his virus
scanner and several other tasks had been running, and when he removed
them he had no problem.

Of course. Virus scanners are a waste of time (and processing power) anyway.

I suspect this is the main problem people have with USB audio
interfaces, and not everyone knows enough to be able to diagnose and
fix it. No one needs a virus checker running while recording sound,
and if you happen to capture some infectious music, the virus checker
won't get it anyway.

You referring to Marilyn Manson? :-)