23 Nov
2020
23 Nov
'20
12:30 a.m.
Hi,
I am currently trying to get the members of my accordion orchestra to
commit to rehearsals using Jamulus. Under Linux, Jamulus uses jackd to
access sound. There is a "JamulusOS" bootable image that will use Linux
to access the soundcard.
Now I want to recommend something to band members (and/or get it myself)
when their sound quality and/or latency is not up to par. My own
collection of sound cards here tends to be Firewire, and supporting that
is not really feasible (the finances would be strained by requiring a
Thunderbolt->Firewire adapter and Thunderbolt is not a given, while
Firewire is not something modern people can think about, and my
Expresscard Firewire adapters still require an actual Expresscard slot).
My own solution right now is an Alesis iO/14 which runs with a roundtrip
latency of about 160 samples at 48kHz. I've just dug out my
still-not-resold RME HDSP Multiface with a PCMCIA Adapter in an
Expresscard-to-PCMCIA adapter which is sort of a reference interface and
it delivers 62 samples roundtrip delay. Which is impressive but nobody
has the interfaces for that anymore and it would not be a recommendation
because of its pricing.
I've lent out one Tascam US-122L interface and Tascam has 64bit drivers
for it on its web page that work reasonably well. Wow. Under Linux, I
have not been able to get it to work recently and it uses really obscure
and undocumented Alsa modes to get at the data: to provide full-duplex
at higher sample rates (48kHz? 96kHz? 24bit? Don't remember) via
USB1.1, it has its own protocols that are not class compliant.
So while it miraculously does work with modern Windows, it would not be
a useful option for JamulusOS. And I am sure I'd get a JamulusOS setup
to run on other people's hardware, and don't have what it takes to make
Windows dropout-free, what with all its secret background processes. So
that interface is only good for people who feel competent at hardware
jiggling with Windows.
So I am lacking a reasonably solid recommendation of (possibly older but
reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
outputs (the lockdown permits two households convening), good
reliability/support under Linux (meaning no obscure software and/or
Windows required for dealing with hardware mixers and mic preamp
boosts), reasonably low roundtrip latency at 48kHz (does not need to be
the insane 5ms from the RME DSP Multiface).
Something that I would not mind taking back. And which is dirt cheap
these days.
I know, I know, wishful thinking. But I will not persuade people to buy
old laptops for this feat, and while I might try starting them off their
built-in soundcards/mics to get them warm to the idea, I need a good
path forward.
Thanks for useful suggestions!
--
David Kastrup
23 Nov
23 Nov
12:53 a.m.
Nov 22 2020, David Kastrup has written:
...
So I am lacking a reasonably solid recommendation of
(possibly older but
reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
outputs
...
Is it worth investigating the Focusrite Scarlett interfaces? I have read
here - a few weeks ago - that the 3rd generation is now supported on
Linux. But the 2nd generation is still listed in some stores. The
Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
the solo - with just one mic preamp - is less than 100 EUR . I think
these smaller Scarletts used to be a favourite with RaspberryPis, as
well.
I don't know the latency, but many people speak very favourably about
them.
HTH.
Best wishes,
Jeanette
--
* Website: http://juliencoder.de - for summer is a state of sound
* Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
* Audiobombs: https://www.audiobombs.com/users/jeanette_c
* GitHub: https://github.com/jeanette-c
I saw your smile
Stay with me a while <3
(Britney Spears)
3:03 a.m.
"Jeanette C." <julien(a)mail.upb.de> writes:
Nov 22 2020, David Kastrup has written:
...
This is basically a no-budget hunt (I don't have the means to make
excessive presents), so store-bought is essentially out. I think one
guy has already gotten a Behringer interface new (I'd not be overly
surprised if it's some laptop-like USB1.1 chip of the "don't expect more
than 15kHz" kind with some somewhat more tolerable preamp, which would
not be the first time I've seen gear from Behringer where the outside
was more impressive than the inside) and there are more dropout problems
than previously (with my old Tascam soundcard) even though it's on its
own USB connector (hopefully on its own controller/port but I don't know
the laptop in person).
I'd not want to suggest anything for which I've not had good experiences
myself, and the budget would likely be at most around what the Behringer
cost new. So realistically, it's definitely going to focus around
something preowned, and likely no longer in current production.
The budget situation would likely not be all that much different even if
I had plenty to spare: "oh, I'll gift you all with interfaces if we go
ahead" is not going to cut it. It has to feel like something everyone
is willing to go through with, and selling the effort is going to be
hard enough without also having to admit that the cost will become
non-trivial.
I think you are right that Focusrite had a reasonable reputation for
their preamps. I'll take a look at what the first generation was about.
--
David Kastrup
So I am lacking a reasonably solid recommendation
of (possibly older but
reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
outputs
...
Is it worth investigating the Focusrite Scarlett interfaces? I have read
here - a few weeks ago - that the 3rd generation is now supported on
Linux. But the 2nd generation is still listed in some stores. The
Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
the solo - with just one mic preamp - is less than 100 EUR . I think
these smaller Scarletts used to be a favourite with RaspberryPis, as
well.
I don't know the latency, but many people speak very favourably about
them. 
9:39 a.m.
On Mon, 23 Nov 2020 02:03:00 +0100
David Kastrup <dak(a)gnu.org> wrote:
"Jeanette C." <julien(a)mail.upb.de>
writes:
If you can get hold of one (possibly ebay), a Mk1 Komplete Audio KA6 fits the
bill perfectly. USB2 class compliant, 2x comby instrument.mic inputs with
switchable phantom power. 2 other analog inputs + 2x digital. also independent
headphone O/P as well as the main outs.
They are built like tanks. I've got one I still use here!
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
Nov 22 2020, David Kastrup has written:
...
This is basically a no-budget hunt (I don't have the means to make
excessive presents), so store-bought is essentially out. I think one
guy has already gotten a Behringer interface new (I'd not be overly
surprised if it's some laptop-like USB1.1 chip of the "don't expect more
than 15kHz" kind with some somewhat more tolerable preamp, which would
not be the first time I've seen gear from Behringer where the outside
was more impressive than the inside) and there are more dropout problems
than previously (with my old Tascam soundcard) even though it's on its
own USB connector (hopefully on its own controller/port but I don't know
the laptop in person).
I'd not want to suggest anything for which I've not had good experiences
myself, and the budget would likely be at most around what the Behringer
cost new. So realistically, it's definitely going to focus around
something preowned, and likely no longer in current production.
The budget situation would likely not be all that much different even if
I had plenty to spare: "oh, I'll gift you all with interfaces if we go
ahead" is not going to cut it. It has to feel like something everyone
is willing to go through with, and selling the effort is going to be
hard enough without also having to admit that the cost will become
non-trivial.
I think you are right that Focusrite had a reasonable reputation for
their preamps. I'll take a look at what the first generation was about. So I am lacking a reasonably solid recommendation
of (possibly older but
reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
outputs
...
Is it worth investigating the Focusrite Scarlett interfaces? I have read
here - a few weeks ago - that the 3rd generation is now supported on
Linux. But the 2nd generation is still listed in some stores. The
Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
the solo - with just one mic preamp - is less than 100 EUR . I think
these smaller Scarletts used to be a favourite with RaspberryPis, as
well.
I don't know the latency, but many people speak very favourably about
them. 
9:42 a.m.
Dear all,
On 23.11.20 02:03, David Kastrup wrote:
"Jeanette C." <julien(a)mail.upb.de>
writes:
> Nov 22 2020, David Kastrup has written:
> ...
>> So I am lacking a reasonably solid recommendation of (possibly older but
>> reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
>> power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
>> outputs
> ...
> Is it worth investigating the Focusrite Scarlett interfaces? I have read
> here - a few weeks ago - that the 3rd generation is now supported on
> Linux. But the 2nd generation is still listed in some stores. The
> Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
> the solo - with just one mic preamp - is less than 100 EUR . I think
> these smaller Scarletts used to be a favourite with RaspberryPis, as
> well.
>
> I don't know the latency, but many people speak very favourably about
> them.
I recently measured latencies (analog to analog) for some sound cards,
including the Focusrite Scarlett solo 3rd gen (2i2 should be the same):
https://github.com/gisogrimm/ovbox/wiki/Soundcards
From all the USB sound cards I tested the Focusrite
Scarlett was the one
with the shortest delay.
Best,
Giso
This is basically a no-budget hunt (I don't have the means to make
excessive presents), so store-bought is essentially out. I think one
guy has already gotten a Behringer interface new (I'd not be overly
surprised if it's some laptop-like USB1.1 chip of the "don't expect more
than 15kHz" kind with some somewhat more tolerable preamp, which would
not be the first time I've seen gear from Behringer where the outside
was more impressive than the inside) and there are more dropout problems
than previously (with my old Tascam soundcard) even though it's on its
own USB connector (hopefully on its own controller/port but I don't know
the laptop in person).
I'd not want to suggest anything for which I've not had good experiences
myself, and the budget would likely be at most around what the Behringer
cost new. So realistically, it's definitely going to focus around
something preowned, and likely no longer in current production.
The budget situation would likely not be all that much different even if
I had plenty to spare: "oh, I'll gift you all with interfaces if we go
ahead" is not going to cut it. It has to feel like something everyone
is willing to go through with, and selling the effort is going to be
hard enough without also having to admit that the cost will become
non-trivial.
I think you are right that Focusrite had a reasonable reputation for
their preamps. I'll take a look at what the first generation was about.
2:33 p.m.
Giso Grimm <gg3137(a)vegri.net> writes:
Dear all,
On 23.11.20 02:03, David Kastrup wrote:
Very good to know, thanks! I'll also take a look at the rest of your tests.
--
David Kastrup
"Jeanette C."
<julien(a)mail.upb.de> writes:
> Nov 22 2020, David Kastrup has written:
> ...
>> So I am lacking a reasonably solid recommendation of (possibly older but
>> reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
>> power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
>> outputs
> ...
> Is it worth investigating the Focusrite Scarlett interfaces? I have read
> here - a few weeks ago - that the 3rd generation is now supported on
> Linux. But the 2nd generation is still listed in some stores. The
> Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
> the solo - with just one mic preamp - is less than 100 EUR . I think
> these smaller Scarletts used to be a favourite with RaspberryPis, as
> well.
>
> I don't know the latency, but many people speak very favourably about
> them.
I recently measured latencies (analog to analog) for some sound cards,
including the Focusrite Scarlett solo 3rd gen (2i2 should be the same):
https://github.com/gisogrimm/ovbox/wiki/Soundcards
From all the USB sound cards I tested the Focusrite Scarlett was the one
with the shortest delay.
3:55 p.m.
David Kastrup <dak(a)gnu.org> writes:
Giso Grimm <gg3137(a)vegri.net> writes:
Question: is there a reason that you are going with buffer sizes of
3*2^n rather than 2^n? I've not actually tried what Jamulus does in
that situation (but will do) but it seems a bit strange to me. Does it
have some inherent advantage?
That being said: I was particularly looking for the Presonus Audiobox
USB these days (since I guess Presonus cards newer than the lacklustre
Firebox are supposed to have good preamps/gains) but with regard to
latency, it doesn't seem like the greatest choice.
--
David Kastrup
Dear all,
On 23.11.20 02:03, David Kastrup wrote:
Very good to know, thanks! I'll also take a look at the rest of your
tests. "Jeanette C."
<julien(a)mail.upb.de> writes:
> Nov 22 2020, David Kastrup has written:
> ...
>> So I am lacking a reasonably solid recommendation of (possibly older but
>> reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
>> power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
>> outputs
> ...
> Is it worth investigating the Focusrite Scarlett interfaces? I have read
> here - a few weeks ago - that the 3rd generation is now supported on
> Linux. But the 2nd generation is still listed in some stores. The
> Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
> the solo - with just one mic preamp - is less than 100 EUR . I think
> these smaller Scarletts used to be a favourite with RaspberryPis, as
> well.
>
> I don't know the latency, but many people speak very favourably about
> them.
I recently measured latencies (analog to analog) for some sound cards,
including the Focusrite Scarlett solo 3rd gen (2i2 should be the same):
https://github.com/gisogrimm/ovbox/wiki/Soundcards
From all the USB sound cards I tested the Focusrite Scarlett was the one
with the shortest delay.
4:18 p.m.
On Mon, 23 Nov 2020 14:55:10 +0100
David Kastrup <dak(a)gnu.org> wrote:
David Kastrup <dak(a)gnu.org> writes:
<some snippage>
Question: is there a reason that you are going with
buffer sizes of
3*2^n rather than 2^n? I've not actually tried what Jamulus does in
that situation (but will do) but it seems a bit strange to me. Does it
have some inherent advantage?
This puzzled me too. I was under the impression that the reason for using powers
of 2 was that buffering code was more efficient. Presumably that would give the
best latency figures.
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
6:01 p.m.
On 23.11.20 15:18, Will Godfrey wrote:
On Mon, 23 Nov 2020 14:55:10 +0100
David Kastrup <dak(a)gnu.org> wrote:
Here is data for the Focusrite Scarlett solo for all period sizes P from
16 to 240 frames in steps of 16 frames:
P frames ms
16 114.847 2.393
32 176.847 3.684
48 232.847 4.851
64 294.847 6.143
80 368.847 7.684
96 424.847 8.851
112 498.847 10.393
128 566.847 11.809
144 616.847 12.851
160 684.847 14.268
176 752.847 15.684
192 802.847 16.726
208 876.847 18.268
240 1000.847 20.851
This is almost perfectly 4*P+48, for all P. I can also start it with P =
37 (an arbitrary prime number), so it looks that there is no limitation
on the period size. Also for such odd numbers it remains 4*P+48 (the
exact delay varies a bit between jack starts, which is normal for USB
devices).
This is jackd2 - I don't know if jackd1 behaves differently (although
both would use the underlying ALSA layer).
I started jack with
jackd --sync -P 90 -d alsa -d hw:$CARD -r $RATE -p $PERIODSIZE
CARD=USB
RATE=48000
At 44.1 kHz it is more like 4*P+70 samples, although there is more
fluctuation.
Best,
Giso
David Kastrup <dak(a)gnu.org> writes:
<some snippage>
Question: is there a reason that you are going
with buffer sizes of
3*2^n rather than 2^n? I've not actually tried what Jamulus does in
that situation (but will do) but it seems a bit strange to me. Does it
have some inherent advantage?
This puzzled me too. I was under the impression that the reason for using powers
of 2 was that buffering code was more efficient. Presumably that would give the
best latency figures.
6:17 p.m.
Giso Grimm <gg3137(a)vegri.net> writes:
Here is data for the Focusrite Scarlett solo for all
period sizes P from
16 to 240 frames in steps of 16 frames:
P frames ms
16 114.847 2.393
32 176.847 3.684
48 232.847 4.851
64 294.847 6.143
80 368.847 7.684
96 424.847 8.851
112 498.847 10.393
128 566.847 11.809
144 616.847 12.851
160 684.847 14.268
176 752.847 15.684
192 802.847 16.726
208 876.847 18.268
240 1000.847 20.851
This is almost perfectly 4*P+48, for all P. I can also start it with P =
37 (an arbitrary prime number), so it looks that there is no limitation
on the period size. Also for such odd numbers it remains 4*P+48 (the
exact delay varies a bit between jack starts, which is normal for USB
devices).
This is jackd2 - I don't know if jackd1 behaves differently (although
both would use the underlying ALSA layer).
I started jack with
jackd --sync -P 90 -d alsa -d hw:$CARD -r $RATE -p $PERIODSIZE
--sync is not documented in jackd2's man page. What does it do?
--
David Kastrup
6:25 p.m.
On 23.11.20 17:17, David Kastrup wrote:
Giso Grimm <gg3137(a)vegri.net> writes:
without --sync jackd2 uses multiple cores whenever possible, at the cost
of one extra buffer. With --sync jackd2 behaves single-threaded but has
one buffer less delay (i.e., two buffers like in jackd1). Using --sync
is thus mostly relevant when delay is the primary concern, and not
performance.
-- Giso
Here is data for the Focusrite Scarlett solo for
all period sizes P from
16 to 240 frames in steps of 16 frames:
P frames ms
16 114.847 2.393
32 176.847 3.684
48 232.847 4.851
64 294.847 6.143
80 368.847 7.684
96 424.847 8.851
112 498.847 10.393
128 566.847 11.809
144 616.847 12.851
160 684.847 14.268
176 752.847 15.684
192 802.847 16.726
208 876.847 18.268
240 1000.847 20.851
This is almost perfectly 4*P+48, for all P. I can also start it with P =
37 (an arbitrary prime number), so it looks that there is no limitation
on the period size. Also for such odd numbers it remains 4*P+48 (the
exact delay varies a bit between jack starts, which is normal for USB
devices).
This is jackd2 - I don't know if jackd1 behaves differently (although
both would use the underlying ALSA layer).
I started jack with
jackd --sync -P 90 -d alsa -d hw:$CARD -r $RATE -p $PERIODSIZE
--sync is not documented in jackd2's man page. What does it do?
7:01 p.m.
On Mon, Nov 23, 2020 at 05:25:34PM +0100, Giso Grimm wrote:
without --sync jackd2 uses multiple cores whenever
possible, at the cost
of one extra buffer. With --sync jackd2 behaves single-threaded but has
one buffer less delay (i.e., two buffers like in jackd1). Using --sync
is thus mostly relevant when delay is the primary concern, and not
performance.
Are you sure about the single-threading being controlled by --sync ?
I've never seen this mentioned before.
AFAIK, with --sync jackd2 writes the outputs to the driver when
all clients have run, same as jackd1. Without --sync it writes
the outputs of the previous cycle before any clients run,
resulting in one period more latency but a bit more resilience
agains xruns.
--
FA
7:32 p.m.
New subject: Affordable well-working USB interface with low latency at 48kHz? [corrected]
On 23.11.20 18:01, Fons Adriaensen wrote:
On Mon, Nov 23, 2020 at 05:25:34PM +0100, Giso Grimm
wrote:
You are right, sorry for the confusion. I always thought that the delay
optimization was at the cost of multi-threading, but this is not true.
I just tested with parallel graphs with heavy load in each graph, and I
get a total jack load which roughly corresponds to the CPU load of the
thread with the highest load, which confirms that parallel processing is
possible also with --sync. Actually the jack load does not seem to be
affected.
-- Giso
without --sync jackd2 uses multiple cores
whenever possible, at the cost
of one extra buffer. With --sync jackd2 behaves single-threaded but has
one buffer less delay (i.e., two buffers like in jackd1). Using --sync
is thus mostly relevant when delay is the primary concern, and not
performance.
Are you sure about the single-threading being controlled by --sync ?
I've never seen this mentioned before.
AFAIK, with --sync jackd2 writes the outputs to the driver when
all clients have run, same as jackd1. Without --sync it writes
the outputs of the previous cycle before any clients run,
resulting in one period more latency but a bit more resilience
agains xruns.
4:50 p.m.
On 23.11.20 14:55, David Kastrup wrote:
David Kastrup <dak(a)gnu.org> writes:
it is based on rumors that with the USB 1.1 audio protocol it latency is
lowest if the fragment size is a multiple of 1ms. I am quite sure that
this was a problem with USB 1.1 devices about 10 years ago.
Whatever jack supports should be fine, with the USB 2.0 devices I don't
see any differences. However, the latencies I measured behave like
4*P + X
where with older cards I have very faint memories of achieving something
like 3*P + Y (although with a longer total delay, at least for short
period sizes).
Giso Grimm <gg3137(a)vegri.net> writes:
Question: is there a reason that you are going with buffer sizes of
3*2^n rather than 2^n? I've not actually tried what Jamulus does in
that situation (but will do) but it seems a bit strange to me. Does it
have some inherent advantage? On 23.11.20 02:03, David Kastrup wrote:
Very good to know, thanks! I'll also take a look at the rest of your
tests. "Jeanette C."
<julien(a)mail.upb.de> writes:
> Nov 22 2020, David Kastrup has written:
> ...
>> So I am lacking a reasonably solid recommendation of (possibly older but
>> reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
>> power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
>> outputs
> ...
> Is it worth investigating the Focusrite Scarlett interfaces? I have read
> here - a few weeks ago - that the 3rd generation is now supported on
> Linux. But the 2nd generation is still listed in some stores. The
> Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
> the solo - with just one mic preamp - is less than 100 EUR . I think
> these smaller Scarletts used to be a favourite with RaspberryPis, as
> well.
>
> I don't know the latency, but many people speak very favourably about
> them.
I recently measured latencies (analog to analog) for some sound cards,
including the Focusrite Scarlett solo 3rd gen (2i2 should be the same):
https://github.com/gisogrimm/ovbox/wiki/Soundcards
From all the USB sound cards I tested the Focusrite Scarlett was the one
with the shortest delay. That being said: I was particularly looking for the
Presonus Audiobox
USB these days (since I guess Presonus cards newer than the lacklustre
Firebox are supposed to have good preamps/gains) but with regard to
latency, it doesn't seem like the greatest choice.
The only Presonus Audiobox USB I have at hand has a broken phantom power
supply, thus I cannot judge the preamps.
Best,
Giso
1:02 p.m.
On Mon, Nov 23, 2020 at 02:03:00AM +0100, David Kastrup wrote:
I think one guy has already gotten a Behringer
interface new (I'd not
be overly surprised if it's some laptop-like USB1.1 chip of the "don't
expect more than 15kHz" kind with some somewhat more tolerable preamp,
which would not be the first time I've seen gear from Behringer where
the outside was more impressive than the inside) and there are more
dropout problems than previously (with my old Tascam soundcard) even
though it's on its own USB connector (hopefully on its own
controller/port but I don't know the laptop in person).
I'd not want to suggest anything for which I've not had good
experiences myself, and the budget would likely be at most around what
the Behringer cost new.
I don't have personal experience of them, but I have seen many people
post positive experiences of using the Behringer U-Phoria line of USB
audio interfaces (UMC202, UMC204, UMC404, UMC1820), including under
Linux. I see them secondhand sometimes for very reasonable prices, but
they are also quite cheap new and widely available.
Apparently they are USB class-compliant, with low latency & reasonable
build quality. Audio quality reportedly close enough to Focusrite for
most uses. Here are some of my bookmarks:
https://linuxmusicians.com/viewtopic.php?p=106377#p106377
https://linuxmusicians.com/viewtopic.php?t=15372
https://www.soundonsound.com/forum/viewtopic.php?f=15&t=72560&p=693…
https://www.ernstrenner.com/linux-reaper-behringer-u-phoria-umc404hd/
https://discourse.ardour.org/t/behringer-umc1820-and-ardour/89949
https://www.gearslutz.com/board/low-end-theory/1113758-behringer-u-phoria-u…
https://www.audiosciencereview.com/forum/index.php?threads/budget-dac-revie…
https://www.pro-tools-expert.com/home-page/2015/10/19/review-of-behringers-…
https://www.infamousmusician.com/behringer-umc1820-review/
So, if someone in your orchestra has had problems with a Behringer
interface, it might be due to something other than the brand. Perhaps
it is plugged into a USB hub that is causing problems. Perhaps it is a
model that is not class-compliant. Perhaps it is a defective unit.
Probably worth troubleshooting the issue before ruling out the brand
altogether.
Good luck with the search, and do please post back in this thread when
you find your solution, whatever it ends up being :)
--
A: When it messes up the order in which people normally read text.
Q: When is top-posting a bad thing?
() ASCII ribbon campaign. Please avoid HTML emails & proprietary
/\ file formats. (Why? See e.g. https://v.gd/jrmGbS ). Thank you.
4:06 p.m.
Sam Kuper <sampablokuper(a)posteo.net> writes:
On Mon, Nov 23, 2020 at 02:03:00AM +0100, David
Kastrup wrote:
That does not match my prejudices :) For my particular use case, sound
quality and to some degree noise floor are secondary considerations
compared to standard compliance, reliability, latency. While I am
personally more of an audio quality buff with a focus on recording, if
the U-Phoria supposedly checks the boxes I need, that would be the
pricing on the cake.
I need to ask the exact model of Behringer that my one orchestra
colleague got. That one's performance (regarding latency/dropouts) did
not really appear to improve upon my stone-age Tascam US-122L brick
(which you can throw basically in any bag without worrying about
anything breaking off). Maybe something related to drivers.
--
David Kastrup
I think one guy has already gotten a Behringer
interface new (I'd not
be overly surprised if it's some laptop-like USB1.1 chip of the "don't
expect more than 15kHz" kind with some somewhat more tolerable preamp,
which would not be the first time I've seen gear from Behringer where
the outside was more impressive than the inside) and there are more
dropout problems than previously (with my old Tascam soundcard) even
though it's on its own USB connector (hopefully on its own
controller/port but I don't know the laptop in person).
I'd not want to suggest anything for which I've not had good
experiences myself, and the budget would likely be at most around what
the Behringer cost new.
I don't have personal experience of them, but I have seen many people
post positive experiences of using the Behringer U-Phoria line of USB
audio interfaces (UMC202, UMC204, UMC404, UMC1820), including under
Linux. I see them secondhand sometimes for very reasonable prices, but
they are also quite cheap new and widely available.
Apparently they are USB class-compliant, with low latency & reasonable
build quality. Audio quality reportedly close enough to Focusrite for
most uses. Here are some of my bookmarks:
5:02 p.m.
On Mon, Nov 23, 2020 at 03:05:49PM +0100, David Kastrup wrote:
I need to ask the exact model of Behringer that my one
orchestra
colleague got. That one's performance (regarding latency/dropouts)
did not really appear to improve upon my stone-age Tascam US-122L
brick (which you can throw basically in any bag without worrying about
anything breaking off). Maybe something related to drivers.
Yes, if you are able to find out which model it is and pinpoint the
problem, do please document it. Either in this thread or somewhere else
where it will be archived online so that other people will be able to
find it if they perform a web search having encountered the same issue.
Thanks, and again good luck in your quest.
--
A: When it messes up the order in which people normally read text.
Q: When is top-posting a bad thing?
() ASCII ribbon campaign. Please avoid HTML emails & proprietary
/\ file formats. (Why? See e.g. https://v.gd/jrmGbS ). Thank you.
17 Dec
17 Dec
4:09 p.m.
David Kastrup <dak(a)gnu.org> writes:
Back to my prejudices: just got an UMC22. Its codec is a Burr-Brown
(TI) PCM2902. Looking up its specs, it's USB1.1 full speed and sports
stuff like
• Stereo ADC
– Analog Performance at V BUS = 5 V
– THD+N = 0.01%
– SNR = 89 dB
– Dynamic Range = 89 dB
– Decimation Digital Filter
– Pass-Band Ripple = ±0.05 dB
– Stop-Band Attenuation = 65 dB
– Single-Ended Voltage Input
– Antialiasing Filter Included
– Digital LCF Included
"Not recommended for new designs" (currently the card is being sold new
everywhere), an USB1.1 (and USB is half-duplex, so this is certainly
responsible for part of the latency) 48kHz design with a 16-bit ADC
specified for slightly above 14bit of precision.
And that's the naked codec, without being impacted by any circuitry
around it.
It's more compact for sure than my current solution at one ensemble
member (mic input into a Mackie Onyx 400F with dead digital circuitry,
out via the plugin jack into the mic input of a laptop).
For -p64 (without --sync) I get
464.320 frames 9.673 ms total roundtrip latency
extra loopback latency: 272 frames
use 136 for the backend arguments -I and -O
(the -O and -I values are independent of -pxx I think).
For comparison: with my Alesis iO|14 (Firewire, a lot more inputs and
outputs) I get 81 for the backend arguments regarding additional
loopback latency. With a Hammerfall DSP (PCMCIA card via expresscard
adapter, so routed through a PCI to PCIx converter) it's 31 if I
remember correctly.
So even in the latency department, I am not really impressed though
given the tests I've seen, this does not seem too uncommon for USB
cards. Though there are plenty by now that are at least USB2.0 and can
consequently, for example, do 96kHz at full-duplex (full-duplex audio,
the USB is still half-duplex).
Sam Kuper <sampablokuper(a)posteo.net> writes:
"Behringer U-Phoria"
Apparently
they are USB class-compliant, with low latency & reasonable
build quality. Audio quality reportedly close enough to Focusrite for
most uses. Here are some of my bookmarks:
That does not match my prejudices :) For my particular use case, sound quality and to some
degree noise
floor are secondary considerations compared to standard compliance,
reliability, latency. While I am personally more of an audio quality
buff with a focus on recording, if the U-Phoria supposedly checks the
boxes I need, that would be the pricing on the cake.
It's most definitely not what I'd use for recording (and with a single
mic input, it's not overly suited for that either). For jamming, it
might fit the bill if you need a phantom power input. Not much
justification for it beyond that I'd say over basically anything cheap
with a line input to be had these days.
I need to ask the exact model of Behringer that my one
orchestra
colleague got. That one's performance (regarding latency/dropouts)
did not really appear to improve upon my stone-age Tascam US-122L
brick (which you can throw basically in any bag without worrying about
anything breaking off). Maybe something related to drivers.
I think it might be that model but I haven't asked back yet.
--
David Kastrup
18 Dec
18 Dec
4:51 p.m.
On Thu, Dec 17, 2020 at 03:08:54PM +0100, David Kastrup wrote:
OK, will be interesting to know.
--
A: When it messes up the order in which people normally read text.
Q: When is top-posting a bad thing?
() ASCII ribbon campaign. Please avoid HTML emails & proprietary
/\ file formats. (Why? See e.g. https://v.gd/jrmGbS ). Thank you.
just got an UMC22. Its codec is a Burr-Brown (TI)
PCM2902. Looking
up its specs, it's USB1.1 full speed and sports stuff like
• Stereo ADC
– Analog Performance at V BUS = 5 V
– THD+N = 0.01%
– SNR = 89 dB
– Dynamic Range = 89 dB
– Decimation Digital Filter
– Pass-Band Ripple = ±0.05 dB
– Stop-Band Attenuation = 65 dB
– Single-Ended Voltage Input
– Antialiasing Filter Included
– Digital LCF Included
"Not recommended for new designs" (currently the card is being sold
new everywhere), an USB1.1 (and USB is half-duplex, so this is
certainly responsible for part of the latency) 48kHz design with a
16-bit ADC specified for slightly above 14bit of precision.
And that's the naked codec, without being impacted by any circuitry
around it.
It's more compact for sure than my current solution at one ensemble
member (mic input into a Mackie Onyx 400F with dead digital circuitry,
out via the plugin jack into the mic input of a laptop).
For -p64 (without --sync) I get
464.320 frames 9.673 ms total roundtrip latency
extra loopback latency: 272 frames
use 136 for the backend arguments -I and -O
(the -O and -I values are independent of -pxx I think).
For comparison: with my Alesis iO|14 (Firewire, a lot more inputs and
outputs) I get 81 for the backend arguments regarding additional
loopback latency. With a Hammerfall DSP (PCMCIA card via expresscard
adapter, so routed through a PCI to PCIx converter) it's 31 if I
remember correctly.
Yes, this is a bit disappointing from the UMC22.
Thank you for taking the time to post the specs & test results, though!
I need to ask
the exact model of Behringer that my one orchestra
colleague got. That one's performance (regarding latency/dropouts)
did not really appear to improve upon my stone-age Tascam US-122L
I think it might be that model but I haven't asked back yet.
1 Dec
1 Dec
5:37 p.m.
David Kastrup <dak-mXXj517/zsQ(a)public.gmane.org> writes:
Hi,
I am currently trying to get the members of my accordion orchestra to
commit to rehearsals using Jamulus. Under Linux, Jamulus uses jackd to
access sound. There is a "JamulusOS" bootable image that will use Linux
to access the soundcard.
Now I want to recommend something to band members (and/or get it myself)
when their sound quality and/or latency is not up to par. My own
collection of sound cards here tends to be Firewire, and supporting that
is not really feasible (the finances would be strained by requiring a
Thunderbolt->Firewire adapter and Thunderbolt is not a given, while
Firewire is not something modern people can think about, and my
Expresscard Firewire adapters still require an actual Expresscard slot).
A note after the fact: the one Mac Mini in question has Thunderbolt
(version 1 or 2) for which there is a Firewire 800 adapter with a
current preowned price tag of about €15 plus portage. You still need to
go down from FW800 to FW400 (what basically all soundcards have).
However, this particular Mac Mini is connected to a large screen from
Apple using some proprietary interface, and that screen acts sort of
like a monster hub with USB, Thunderbolt, and even an FW800 connector.
So when checking the connectivity of some Mac, it may be worth checking
the screen as well.
With regard to interfaces, I am likely going for Line-in connectors when
available. Soundcards with insert connectors (I even have a Mackie Onyx
400F with dead logic that can be taken out, leaving only 4 good analog
preamps with unbalanced outputs via the insert connectors) make for
sensible preamps. I also have some half-broken mixer (one strip dead,
noisy headphone out) that will deliver preamps, and when feeding those
into Line-in or even mic-in of lousy soundcards, the gain is such that
you get good SNR.
There are soundcards in "standalone" mode that will route their inputs
to line out (also handheld recorders) but those tend to do the "routing"
digitally, meaning that you get at least something like 8ms of
additional delay.
So I do get to pass around a number of shoestring and gum solutions that
may or may not prompt some people to get something better.
And it was sobering to figure out that driver support under Linux
appears to die faster than under Windows (MacOSX the jury is still out
on).
Tascam US-122L works well with 64bit Windows drivers, has stopped
working with Linux (and it only ever worked using some undocumented
secret sauce protocol you needed to declare to ALSA).
Mackie Onyx Satellite has stopped working with snd_dice. I'll see
whether it works with a Mac (though it has really lousy phantom power,
sth like 36V or so which cannot be used in tandem with a hi-impedance
input because of converter whine).
Dug out an old iSight Firewire webcam. That one works with Linux audio
but requires a buffer size of at least something like 485 samples,
resulting in too much latency for orchestra practice. That appears like
a design constraint of its Firewire packaging, so it likely will not go
away when connecting to an actual Mac. It might work for video
conferencing, though it's constrained to VGA size.
For one-mic-per-client setups, something like Focusrite Scarlett Solo
looks like a good idea, but I have not gathered actual experience with
it. Still, if someone asks for advice, that's likely what I'd point to
when the cost is deemed acceptable.
We'll see...
--
David Kastrup
1237
days inactive
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days old
linux-audio-user@lists.linuxaudio.org
19 comments
6 participants
participants (6)
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David Kastrup -
Fons Adriaensen -
Giso Grimm -
Jeanette C. -
Sam Kuper -
Will Godfrey