ALSA for audio
 

In article , unruh
wrote:
On 2013-02-13, Davey wrote:

Having read the whole article now, one question: Can I use the Mic
Input on my laptop, which already has a built-in Mic, as a Line Input,
or is there going to be some horrid mis-match? I have a tape deck
nearby, and I would like to send its output into the laptop, but it
only has the Mic Input.

In principle yes. However most mic inputs have a dc voltage on them to
power the FET on the microphones. Thus your line out should make sure it
has a capacitive output or you could have a fight.

You may also find that the mic input clips 'line' level voltages since a
mic input may have a preamp stage which can't cope with such 'high' levels.
Any hardware gain adjustment may be after this stage. This, again, all
depends on the specific hardware in the box.

In general I'd be wary of the analogue stages of hardware in a normal
computer. Might be OK. But a dedicated special purpose external 'sound
card' may well give much better results.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

ALSA for audio
 

On Thu, 14 Feb 2013 09:20:15 +0000 (GMT)
Jim Lesurf wrote:

In article , Davey
wrote:


Don't forget to point us to the magazine with your article in it.

Thereby hangs a tale... :-)

What has appeared on my website was originally aimed at being
published in 'Linux Format'. I sent them a copy and their Editor
said, yes, they wanted to publish. We agreed it should be a 4-page
'tutorial' and I planned others to follow.

I got their contract document from the Publishers. Didn't like the
look of it.

The essence of that was their contract wanted *all* rights on an
exclusive basis. Inc all 'moral' rights, etc. The lot.

I explained to the Editor that I only sell 'first serial' rights and
*non* exclusive republication rights as I wish to be able to re-use
parts of material, or put the articles on the web at a later date.
The point being to ensure that useful data isn't 'lost' to people
later in time. (When they can't get the mag, or the publisher shuts
down.)

I've not had any problem with other publishers with this. e.g. Hi Fi
News are happy with it.

But their response was that they insist on taking all rights. Full
stop.

I pointed out this seemed particularly weird as an attitude for a
*Linux* magazine! :-) The Editor agreed, but said it wasn't in his
hands, and the publishers insist.

So no publication in Linux Format. Fortunately, I don't write for a
living, so can decide to go without the fees.

However there will be an article in Hi Fi News. Just have to get
around to writing it. :-)

Shame, though, as I'd like to write about this for LXF. May see if
they will publish a brief item pointing at the webpages for details.
Might get though that way...




Well, that is sad. It sounds as though the editor didn't really care to
even try to change Management's thinking, but he may know there is no
chance of changing their ideas. I remember looking at Photobucket's
Ts&Cs once, and being horrified at what they took as their rights.


I had a very quick glance at your webpage, and I noticed all the
vertical bars; whereas my system just has several [00]s, due to a
different internal setup. Hopefully this is covered if I read it in
more depth. I will follow this with interest, thanks.

It depends entirely on the hardware ALSA finds. Some devices have
gain or volume controls. Others don't (and so you rely on software
you use to scale gains or volumes). I get different alsamixer
displays on all three of the Linux machines I use.


So many options, so much scope for confusion of the unwary......

--
Davey.

ALSA for audio
 

On Thu, 14 Feb 2013 02:21:21 +0000 (UTC)
Martin Gregorie wrote:

On Thu, 14 Feb 2013 00:22:51 +0000, Davey wrote:


snip


Alternatively, you might want to look at using an Ion U-Record, just
under 30 squids from Amazon. Its a USB stereo ADC, accepts line-in or
MC pickup levels and is powered off the USB connection. Works well
with Audacity. RCA connectors on the analogue side. I got mine
because it was cheap to see if this was a good way to digitise some
tapes and vinyl and have kept it because I can't see any reason the
replace it with a more expensive device.

Caveat: mine was working well in March last year with whatever the
semi- current Fedora was (probably F15) and Audacity (probably 1.38).
When I tried it a day or two ago (F17, Audacity 2.0.2) no joy: looks
like there's a problem with either the OS or Audacity and the USB
codec. This might be specific to the U-record but it could equally
apply to all external USB sound cards. I bugged it against Fedora but
no resolution as yet.

However, I reckon its hard to go wrong at that price, especially as
it uses a decent Burr-Brown ADC.



I had seen adverts. for Ion stuff, but was wary due to many bad reports
of their slide and negative copying devices; I just made my own, from
a couple of cardboard boxes and Sellotape, and have
successfully digitised hundreds of slides for a History Society.
In my case, I already had a working setup, with a proper sound card
and Audacity in an old Dell desktop PC, but the PC was moved to the
other end of the house, for use with Zoneminder and CCTV. As my need of
this recording setup is now rare, I think I do not need to buy more
stuff, where there is little space for it anyway, for a limited use, but
rather I will take the cassette deck down to the PC to do the job, and
just leave it there, under the PC. But I should one day re-load
Audacity, as it got hosed when I did a full new Ubuntu installation.
But I thank you for your thoughts, it is good to hear that the Ion
device does work.
Another thought:
I have two different TV- PC USB devices. I wonder if one of them would
do the same job, just using the stereo sound inputs? Even if I had to
provide a dummy TV signal for it to lock on to while acting as a TV
device, I could then possibly take the recorded sound track, although I
would need to work out what to do to enable this, and then to do it.
But is it viable? Maybe it would just work with Audacity as it is.
--
Davey.

ALSA for audio
 

On Thu, 14 Feb 2013 00:11:13 GMT
unruh wrote:

On 2013-02-13, Davey wrote:
On Wed, 13 Feb 2013 09:45:53 +0000 (GMT)
Jim Lesurf wrote:

In article , Davey
wrote:
On Tue, 12 Feb 2013 16:39:20 +0000 (GMT) Jim Lesurf
wrote:


http://www.audiomisc.co.uk/Linux/ALSA/ALSAforUsers.html


I shall test-drive it, and see how well it reflects the problems
I had, and you fixed!

You'll probably need the 'next' page - which I've not written
yet! :-)

That will cover things like using aplay to investigate your card
playout devices and how to write a suitable .asoundrc to control
and direct output. Thought it best to start with alsamixer, etc,
as it means starting with a nice graphic display showing users
what they have.

However, first, I intend writing a magazine article. Needed a
wepage in place first so I could give a URL to point readers
toward for more specific data. Once the article is done I'll have
a while to add another page or two to the above, and then all will
be findable by someone who reads the magazine.

Slainte,

Jim


Having read the whole article now, one question:
Can I use the Mic Input on my laptop, which already has a built-in
Mic, as a Line Input, or is there going to be some horrid
mis-match? I have a tape deck nearby, and I would like to send its
output into the laptop, but it only has the Mic Input.

In principle yes. However most mic inputs have a dc voltage on them to
power the FET on the microphones. Thus your line out should make sure
it has a capacitive output or you could have a fight.



On a similar vein, but in the opposite direction, I would like to send
the PC headphone output signal to my HiFi, since my stupid TV will
only send out of the SCART connector the sound track from whatever TV
channel it's tuned to, even if the HDMI input is selected for display.
But I know that there is going to be a mismatch between the PC's output
and any input on the amplifier, as it is not designed to accept such an
input signal.
Another idea shelved.
--
Davey.

ALSA for audio
 

Davey wrote...

But I know that there is going to be a mismatch between the PC's output
and any input on the amplifier, as it is not designed to accept such an
input signal.

You shouldn't have any problems as long as you take it easy with the
volume control. In pre USB days this was the only practical way to get
audio from a PC to the hifi.

I'm currently feeding the output of a cheap and quite cheerful USB
audio dongle:
http://www.lindy.co.uk/usb-2-audio-adapter/42961.html
to a 70's JVC amplifier which has an input sensitivity of 150mV and
have not noted any mismatch or overload. More recent amps designed to
cope with the typical 2V output of CD players should have more
headroom.

--
Ken O'Meara

ALSA for audio
 

In article , Davey
wrote:
On Thu, 14 Feb 2013 09:20:15 +0000 (GMT) Jim Lesurf
wrote:


But their response was that they insist on taking all rights. Full
stop.

I pointed out this seemed particularly weird as an attitude for a
*Linux* magazine! :-) The Editor agreed, but said it wasn't in his
hands, and the publishers insist.

Well, that is sad. It sounds as though the editor didn't really care to
even try to change Management's thinking, but he may know there is no
chance of changing their ideas.

From what he said my feeling is that he has tried and given up. They own
the mag and set the rules. In a way, no different to, say, 'left wing'
magazines that treat their staff poorly, etc, when you'd expect them to
care about pay and conditions and how to treat staff.

Bear in mind that many publishers run a 'stable' of mags purely on the
basis of leaving all content, etc, to the editorial staff, and treating the
result as a widget factory providing income.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

ALSA for audio
 

On Thu, 14 Feb 2013 12:23:35 -0000
UnsteadyKen wrote:


Davey wrote...

But I know that there is going to be a mismatch between the PC's
output and any input on the amplifier, as it is not designed to
accept such an input signal.

You shouldn't have any problems as long as you take it easy with the
volume control. In pre USB days this was the only practical way to
get audio from a PC to the hifi.

I'm currently feeding the output of a cheap and quite cheerful USB
audio dongle:
http://www.lindy.co.uk/usb-2-audio-adapter/42961.html
to a 70's JVC amplifier which has an input sensitivity of 150mV and
have not noted any mismatch or overload. More recent amps designed to
cope with the typical 2V output of CD players should have more
headroom.


The Amp. in question is a Goodmans Module 80, of the late 1970s! Works
fine, after I replaced some blown lamps, and some funny-looking bulging
capacitors, but cannot be described as 'more recent'! It is of the same
era as your JVC.
But I might still try it, I have a collection of old phono and jack
sockets from a much-loved but now dead cassette player, so I should be
able to make up the correct 3.5mm jack to 5-pin DIN connector required.
Your dongle (that sounds rude, but isn't meant to be!) looks good
value.
Thanks for help and ideas.
--
Davey.

ALSA for audio
 

In article , Davey
wrote:
On Thu, 14 Feb 2013 12:23:35 -0000 UnsteadyKen
wrote:



The Amp. in question is a Goodmans Module 80, of the late 1970s! Works
fine, after I replaced some blown lamps, and some funny-looking bulging
capacitors, but cannot be described as 'more recent'! It is of the same
era as your JVC.

I'd have to dig though my old mags and documents to be sure. But I'd guess
it uses DIN sockets and has a line sensitivity of about 500 - 100 mV. So
would need some resistors to cope with modern line voltages (circa 1V to
2V).

IIRC the audio on a SCART is about 1V. So could also be used. You can buy
adaptors for this which output to phono/RCA sockets. CPC is your friend.
:-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

ALSA for audio
 

I've now added another page at

http://www.audiomisc.co.uk/Linux/ALS...reSilence.html

which focusses more on how to set up audio playback as you prefer.

I have at least one more page in mind, but will try again to make my mind
get on to writing an article instead! :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

ALSA for audio
 

On Thu, 14 Feb 2013 13:55:37 +0000 (GMT)
Jim Lesurf wrote:

In article , Davey
wrote:
On Thu, 14 Feb 2013 12:23:35 -0000 UnsteadyKen
wrote:



The Amp. in question is a Goodmans Module 80, of the late 1970s!
Works fine, after I replaced some blown lamps, and some
funny-looking bulging capacitors, but cannot be described as 'more
recent'! It is of the same era as your JVC.

I'd have to dig though my old mags and documents to be sure. But I'd
guess it uses DIN sockets and has a line sensitivity of about 500 -
100 mV. So would need some resistors to cope with modern line
voltages (circa 1V to 2V).

IIRC the audio on a SCART is about 1V. So could also be used. You can
buy adaptors for this which output to phono/RCA sockets. CPC is your
friend. :-)

Slainte,

Jim


I already send the audio from the TV's SCART output to the Goodmans,
but as I mentioned, it only sends the audio of whatever TV channel the
TV is or was tuned to, so is no use when I'm using the PC as a
video source; hence the desire to use the PC's headphone output instead.
I can look for the specs. on the Goodmans, but I think I will be in no
hurry to do this, in case it damages something. I would be using the
Tape Recorder Input on the Goodmans. Physically, I can get the signals
there, after a bit of soldering.
Interestingly, the DIN socket from the dead donor cassette deck has a
bunch of resistors on the DIN socket board, but I can't see what
colours the bands are, they are hidden. At the moment. I have a DIN-DIN
cable already, it's a matter of getting the signal to it that requires
the soldering and construction of a connector. This is possible.
--
Davey.