12 Apr
2008
12 Apr
'08
1 p.m.
The first (beta) release of Jmeters is available at
<http://www.kokkinizita.net/linuxaudio/downloads>
Jmeters is a Jack multichannel audio level meter app.
It looks very similar to meterbridge since it uses the
same pixmaps.
This first release offers VU, PPM and stereo versions of the
same. The stereo versions have two indicator needles on the
same scale. I've never seen a twin VU, but stereo (or M/S)
PPMs *do* exist. Later releases will add bargraph meters,
digital peak indicators for the analog ones, and a stereo
correlation meter.
The main difference to meterbridge is that Jmeters has the
correct ballistics for both the VU and the PPM.
The VU meter measures the average of the absolute value of
the signal, 'average' meaning a second order filter that
reaches 99% in 300ms and overshoots between 1.0 and 1.5%.
It is calibrated to indicate 0dB for a sine wave at -10dB
w.r.t. digital full scale (which is +/-1 peak in this case).
The particular VU scale used is not entirely linear and
starts at -20dB (it's one designed for a passive VU meter
with a diode bridge), so the meter will not move at all
for inputs below that level. Later versions may use a
VU scale designed for an active meter which doesn't have
this threshold.
The PPM is a pseudo-peak meter. It will indicate 80% of
the steady-state value for a 10ms burst, and fall by 24db
in 2.8s. Each scale division (1..7) represents 4dB. It is
calibrated to indicate '7' (+12 dB on the EBU scale) for
0dB FS.
For speech and music with distinct short peaks the PPM
will usually indicate higher. For music with continuous
long notes, and for heavily compressed signals the VU
indicates higher. Both meters require some 'getting used
to' in order to read them correctly.
You can modify the calibration by using the -g(ain) option,
but it should normally not be necessary.
Enjoy !
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
12 Apr
12 Apr
2:25 p.m.
Great stuff. thanks!
- Mark
On Sat, Apr 12, 2008 at 7:56 AM, Fons Adriaensen <fons(a)kokkinizita.net> wrote:
The first (beta) release of Jmeters is available at
<http://www.kokkinizita.net/linuxaudio/downloads>
Jmeters is a Jack multichannel audio level meter app.
It looks very similar to meterbridge since it uses the
same pixmaps.
This first release offers VU, PPM and stereo versions of the
same. The stereo versions have two indicator needles on the
same scale. I've never seen a twin VU, but stereo (or M/S)
PPMs *do* exist. Later releases will add bargraph meters,
digital peak indicators for the analog ones, and a stereo
correlation meter.
The main difference to meterbridge is that Jmeters has the
correct ballistics for both the VU and the PPM.
The VU meter measures the average of the absolute value of
the signal, 'average' meaning a second order filter that
reaches 99% in 300ms and overshoots between 1.0 and 1.5%.
It is calibrated to indicate 0dB for a sine wave at -10dB
w.r.t. digital full scale (which is +/-1 peak in this case).
The particular VU scale used is not entirely linear and
starts at -20dB (it's one designed for a passive VU meter
with a diode bridge), so the meter will not move at all
for inputs below that level. Later versions may use a
VU scale designed for an active meter which doesn't have
this threshold.
The PPM is a pseudo-peak meter. It will indicate 80% of
the steady-state value for a 10ms burst, and fall by 24db
in 2.8s. Each scale division (1..7) represents 4dB. It is
calibrated to indicate '7' (+12 dB on the EBU scale) for
0dB FS.
For speech and music with distinct short peaks the PPM
will usually indicate higher. For music with continuous
long notes, and for heavily compressed signals the VU
indicates higher. Both meters require some 'getting used
to' in order to read them correctly.
You can modify the calibration by using the -g(ain) option,
but it should normally not be necessary.
Enjoy !
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
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Linux-audio-user(a)lists.linuxaudio.org
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5:09 p.m.
Fons Adriaensen:
The first (beta) release of Jmeters is available at
<http://www.kokkinizita.net/linuxaudio/downloads>
Hi Fons. Very nice, I like vu's so much. Is there a way to up-tweak
the frame rate? Shouldn't -t svu result in 2 inputs? I only get 1
input with whatever I try. What's -c doing?
Wolfgang
5:19 p.m.
Wolfgang Woehl wrote:
Fons Adriaensen:
yeah, this is really a nice one!
thanks for sharing it, fons.
The first (beta) release of Jmeters is available
at
<http://www.kokkinizita.net/linuxaudio/downloads>
Hi Fons. Very nice, I like vu's so much. Is there a way to up-tweak
the frame rate? Shouldn't -t svu result in 2 inputs? I only get 1
input with whatever I try.
i see this if i connect aqualung, but if i take
mhwavedit jmeter is
running stereo. kinda strange.
the command line i am using:
jmeters -t svu aqualung:out_L aqualung:out_R
cheers,
doc
cheers,
doc
What's -c doing?
Wolfgang
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Linux-audio-user(a)lists.linuxaudio.org
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
6:21 p.m.
On Sat, Apr 12, 2008 at 09:19:09PM +0200, Dragan Noveski wrote:
i see this if i connect aqualung, but if i take
mhwavedit jmeter is
running stereo. kinda strange.
I don't really understand what is the problem you see...
the command line i am using:
jmeters -t svu aqualung:out_L aqualung:out_R
This should give you a single VU meter with two
'hands', red = L, green = R.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
14 Apr
14 Apr
12:25 p.m.
Fons Adriaensen wrote:
On Sat, Apr 12, 2008 at 09:19:09PM +0200, Dragan
Noveski wrote:
hallo fons, thanks for taking your time.
obviously, the stereo file i played with aqualung was that much well
leveled, that i did not realized that there are two 'hands'. so,
everything is working here, sorry for the noise!
cheers,
doc
i see this if i connect aqualung, but if i take
mhwavedit jmeter is
running stereo. kinda strange.
I don't really understand what is the problem you see...
the command line i am using:
jmeters -t svu aqualung:out_L aqualung:out_R
This should give you a single VU meter with two
'hands', red = L, green = R.
Ciao,
12 Apr
12 Apr
6:18 p.m.
On Sat, Apr 12, 2008 at 09:09:04PM +0200, Wolfgang Woehl wrote:
The frame rate is fixed in this version (I'll make it a command
line param later). You could modify line 192 in mainwin.cc which
sets the period in microseconds. CPU usage will we proportional
to the rate...
The number of inputs is equal to the number of jack ports you
give on the command line. With -t svu you should specify two
ports.
-c set the maximum number of meter in a single row.
If there are more ports a new row is started.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
The first
(beta) release of Jmeters is available at
<http://www.kokkinizita.net/linuxaudio/downloads>
Hi Fons. Very nice, I like vu's so much. Is there a way to up-tweak
the frame rate? Shouldn't -t svu result in 2 inputs? I only get 1
input with whatever I try. What's -c doing?
7:25 p.m.
Fons Adriaensen:
The frame rate is fixed in this version (I'll make
it a command
line param later). You could modify line 192 in mainwin.cc which
sets the period in microseconds. CPU usage will we proportional
to the rate...
20.000 (50fps) seems to work fine and makes the metering really
useable.
Very nice, I'll sell my TV too now, this vu is all I need.
Thank you, Fons.
Wolfgang
7:32 p.m.
Fons Adriaensen:
I've never seen a twin VU
Wouldn't physical "twin VU's" be terribly difficult to build because
of magnetic correlation?
The main difference to meterbridge is that Jmeters has
the
correct ballistics for both the VU and the PPM.
The VU meter measures the average of the absolute value of
the signal, 'average' meaning a second order filter that
reaches 99% in 300ms and overshoots between 1.0 and 1.5%.
It is calibrated to indicate 0dB for a sine wave at -10dB
w.r.t. digital full scale (which is +/-1 peak in this case).
Are these numbers modelled after a real device?
Wolfgang
8:08 p.m.
On Sat, Apr 12, 2008 at 11:32:49PM +0200, Wolfgang Woehl wrote:
The VU meter is defined by ANSI, BS and IEC standards.
For the PPM there are BS and EBU standards.
The numbers quoted are those I learned long ago when I
was a student at the broadcasting and performing arts
academy in Brussels... Nostalgia indeed...
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
The VU meter
measures the average of the absolute value of
the signal, 'average' meaning a second order filter that
reaches 99% in 300ms and overshoots between 1.0 and 1.5%.
It is calibrated to indicate 0dB for a sine wave at -10dB
w.r.t. digital full scale (which is +/-1 peak in this case).
Are these numbers modelled after a real device? 
9:30 p.m.
On Sat, 12 Apr 2008 23:32:49 +0200
Wolfgang Woehl <tito(a)rumford.de> wrote:
Fons Adriaensen:
My 1973 2 track Brenell didn't have a problem <sigh>
They were edgewise meters stacked one above the other and were HUGE.
--
Will J Godfrey
http://www.musically.me.uk
I've never seen a twin VU
Wouldn't physical "twin VU's" be terribly difficult to build because
of magnetic correlation?
9:46 p.m.
On Sun, Apr 13, 2008 at 12:30:33AM +0100, Folderol wrote:
My 1973 2 track Brenell didn't have a problem
<sigh>
They were edgewise meters stacked one above the other and were HUGE.
Real VU meters must be huge. Even if you have 24 of them.
I used a Brenell for a few months (loaned) - a lovely machine.
Ciao,
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
6069
days inactive
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11 comments
5 participants
participants (5)
-
Dragan Noveski -
Folderol -
Fons Adriaensen -
Mark Knecht -
Wolfgang Woehl