Hi all,

I would be interested in any experience the group has with PC based
audio equipment testing. It seems to me that with readily available PC
soundcards now having up to 24 bit 96kHz sampling, and capable of
producing tones up to 48 kHz or so, a variety of testing could be
implemented fairly easily, with appropriate software. I'm thinking of
oscilloscopes, audio signal generators, spectrum analysers, distortion
analysers etc. If anybody has any experience of paticular
software/hardware I'd be very interested in your comments.

many thanks,

Pete.

I have used Winscope, AnalFreq (a spectrum analyser suited for amp work)
and there's a few Python based audio oscillator/multi tool toolkits. All
freeware.

My s/c is a Yamaha DS-XG50, capable of a 96 KHz max sample rate in forced
mono.

--
Gregg
*Perhaps it's useful, even if it can't be SPICE'd*
Visit the GeeK Zone - http://geek.scorpiorising.ca

On Thu, 11 Sep 2003 15:35:21 +0000, Shiva wrote:


Find the
Velleman site - they have demo software. The scope is tiny - about 12 by 1
by 9, optically isolated from your computer, can auto-range, and, with a
standard 10:1 probe will serve your basic needs. I am in no way related to
the manufacturer - i just like the product (cheap & takes up no bench space.

http://www.vellemanusa.com/

I had started building a similar device for myself, but given the cost of
this kit, I would go with it instead.

Russ

Shiva wrote:
[...]

Hi Pete -
Fred's done a bunch of stuff with soundcards - if you ask him *nicely*,
he'll send you his white / pink / brown noise files. [...]

Thanks, dim. The reason I didn't reply is because Pete was asking for
high sampling-rate stuff, and my test files are only 44.1 kHz. But in
any event, here they a

http://www.dogstar.dantimax.dk/testwavs/index.htm

or he

http://www.stockportradiosociety.co....sp?FolderID=27

Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
+--------------------------------------------+

Hi,

I am using a software from this site http://www.audiotester.de/ The
software can do spectrum analysis and also make the audiocard work as a
low distorsion signal generator. Depending on the audio card performance
the sofware can handle up to 48kHz which is very useful for amplifier
testing. Dynamic range depends on the noise level of the audiocard, in one
of my PCs the built in audiocard permits about 110 dB dynamic range which
is probabaly more then enough for most users, on the other hand I have
another PC where the noise level from the main board disturbs the
measurements and limit the dynamic range to about 85dB so performance
depends on the audiocard. The software also includes a oscilloscope but I
dont think this is so useful due to the limited BW so I use a 40MHz
ordinary analogue scope.

This is one of the lowest cost options I have found and it works very
well, a demoversion can be downloaded free of charge but stops
automatically after a few minutes of use so you need to restart the
program.

Regards Hans

Pete67 wrote:

Hi all,

I would be interested in any experience the group has with PC based
audio equipment testing. It seems to me that with readily available PC
soundcards now having up to 24 bit 96kHz sampling, and capable of
producing tones up to 48 kHz or so, a variety of testing could be
implemented fairly easily, with appropriate software. I'm thinking of
oscilloscopes, audio signal generators, spectrum analysers, distortion
analysers etc. If anybody has any experience of paticular
software/hardware I'd be very interested in your comments.

many thanks,

Pete.

"Pete67" wrote in message
om...
Hi all,

I would be interested in any experience the group has with PC based
audio equipment testing. It seems to me that with readily available PC
soundcards now having up to 24 bit 96kHz sampling, and capable of
producing tones up to 48 kHz or so, a variety of testing could be
implemented fairly easily, with appropriate software. I'm thinking of
oscilloscopes, audio signal generators, spectrum analysers, distortion
analysers etc. If anybody has any experience of paticular
software/hardware I'd be very interested in your comments.


Also see http://audio.rightmark.org/ .

You can just loop the amp with dummy load and attenuator along with the
sound card.

.

You can just loop the amp with dummy load and attenuator along with the
sound card.




That dummy load needs to be more than just a power resistor. It should
look like a speaker to the amp. Possibly an inductance in series or
parallel
(or some combination) with a resistor. Or a speaker located in another
room (assuming no neighbors).

"Robert Casey" wrote in message
...

You can just loop the amp with dummy load and attenuator along with the
sound card.

That dummy load needs to be more than just a power resistor. It should
look like a speaker to the amp. Possibly an inductance in series or
parallel
(or some combination) with a resistor. Or a speaker located in another
room (assuming no neighbors).

Agreed.

You didn't look at the URL in my other post, did you?

;-)

Here it is, again.

http://www.pcavtech.com/pwramp/macrot-5000VZ/index.htm

This test shows the results of both resistive and reactive load testing.

The loudspeaker simulator I recommend is described in detail in the lower
part of this page:

http://www.pcavtech.com/pwramp/index.htm

"Robert Casey" wrote in message
...

You can just loop the amp with dummy load and attenuator along with the
sound card.


That dummy load needs to be more than just a power resistor. It should
look like a speaker to the amp.


** But which speaker ? There is a huge variation in impedance
characteristics.


Possibly an inductance in series or parallel (or some combination) with a
resistor.


** THD and response testing is always done with resistive loads - so
specs can be fairly compared with other amps. A reactive load condition can
be simulated with a additional inductor or capacitor in series with the
resistor load - the frequency where the impedance of the additional
element equals the resistor value is usually the one most likely to provoke
a reaction from any VI limiting that may be installed.


Or a speaker located in another room (assuming no neighbors).


** Speakers are a very often non-linear loads so will exaggerate THD figures
if the amp has only a modest damping factor ( like tube amps do) .

As well, speakers are easily damaged by continuous high power levels -
so not a practical option for amp performance testing.



................ Phil

This is where the whole Krueger/Pinkerton axis wobbles into
absurdity.

Which speaker should the load look like, and in which room?

The simple reproductionist argues that, in order to achieve the
necessary linearity throughout the chain from the original sound
source to my room, each link must itself be linear. When he says
that no speaker (and presumably no microphone) gets close to hi-fi,
Arny consigns his whole edifice to obscurity. It is meaningless in
the real world, and its central tenet cannot be tested.

According to a recent discussion on microphone placement, if Arny
had his way I would end up sitting under the piano.

Just a token resistance...I know Arny has heard it all before, and
is obviously committed to his cause come hell or high water.

I think we are into complimentary transforms here. Mess about until
it sounds right, then maybe measure for fun.

cheers, Ian




"Robert Casey" wrote in message
...


.

You can just loop the amp with dummy load and attenuator along
with the
sound card.




That dummy load needs to be more than just a power resistor. It
should
look like a speaker to the amp. Possibly an inductance in series
or
parallel
(or some combination) with a resistor. Or a speaker located in
another
room (assuming no neighbors).

Mindless is going a bit far, I think. Like I said, it was a token
niggle. I don't want to end up under the piano anyway, as it
happens.

I am happy to accept that microphones may be capable of Arny's hi fi
standard, but perhaps you could direct me to the discussion of how
fidelity is measured wrt microphones. Perhaps I should assume it is
a matter of perfect pressure-to-voltage conversion from air to
output. Bit of a problem there, come to think of it...how would you
know what the pressures would have been had the microphone not been
there?

The faults of speakers may be easily identifiable if you accept
Arny's case, which I don't. There is a circular argument there that
I am not interested in. Neither does it detract from the fact that
a perfection that has never been attained cannot be used as a
standard for the purpose of comparison by ear.

You need to think about your arguments carefully, Phil.

cheers, Ian

"Phil Allison" wrote in message
...

"Ian Iveson" wrote in message
...

This is where the whole Krueger/Pinkerton axis wobbles into
absurdity.


** You're looking a bit wobbly yourself, Ian.


Which speaker should the load look like, and in which room?


** The one you intend to use would be a good place to start.



The simple reproductionist argues that, in order to achieve the
necessary linearity throughout the chain from the original sound
source to my room, each link must itself be linear.


** Well, since non-linearity produces signals additional to
the source
signal ......


When he says that no speaker (and presumably no
microphone)......


** That is a BIG presumption. Microphones are way superior
to speakers
in terms of response range, linearity and SPL handling. Mics
intended for
measurments can have flat response from DC to 50 kHz and handle up
to 150 dB
SPL at any frequency.


gets close to hi-fi, Arny consigns his whole edifice to
obscurity. It is
meaningless in
the real world, and its central tenet cannot be tested.


** The imperfections of even the best speakers are easlily
indentified
and heard.

Your assertions are mindless, at best.



According to a recent discussion on microphone placement, if
Arny
had his way I would end up sitting under the piano.


** If that is where you need to place a mic to capture the
sound pressure
signal ....



Just a token resistance...I know Arny has heard it all before,
and
is obviously committed to his cause come hell or high water.

I think we are into complimentary transforms here. Mess about
until
it sounds right, then maybe measure for fun.


** Ok, who needs guys like Bill Shakespeare ?? - everyone
knows that
a million monkeys at typewriters can produce the same stuff in no
time.






........... Phil

"Ian Iveson" wrote in message
...

Mindless is going a bit far, I think. Like I said, it was a token
niggle. I don't want to end up under the piano anyway, as it
happens.


** I see you do not answer other's points but avoid them by pompous top
posting.


I am happy to accept that microphones may be capable of Arny's hi fi
standard, but perhaps you could direct me to the discussion of how
fidelity is measured wrt microphones.


** Your ignorance is only matched by your smugness.


Perhaps I should assume it is a matter of perfect pressure-to-voltage
conversion from air to
output. Bit of a problem there, come to think of it...how would you
know what the pressures would have been had the microphone not been
there?


** Heisenberg's principle applied to the macro ??



The faults of speakers may be easily identifiable if you accept
Arny's case, which I don't.


** Then you are a fool.


There is a circular argument there that I am not interested in.


** No. You are spinning in circles - makes it look to you like the world
is spinning.



Neither does it detract from the fact that a perfection that has never been
attained cannot be used as a
standard for the purpose of comparison by ear.


** Your mad assertions do not constitute facts.


You need to think about your arguments carefully, Phil.



** Says someone who has not had a rational thought for some time.





............. Phil

"Shiva" wrote in message
...

"Phil Allison" wrote in message
...

"Ian Iveson" wrote in message
...

This is where the whole Krueger/Pinkerton axis wobbles into
absurdity.


** You're looking a bit wobbly yourself, Ian.


Ad Hominem is da best kind'o argument.


** One ad hominem deserves another.




Which speaker should the load look like, and in which room?


** The one you intend to use would be a good place to start.


For evaluating an amplifier?


** Yep.



The simple reproductionist argues that, in order to achieve the
necessary linearity throughout the chain from the original sound
source to my room, each link must itself be linear.


** Well, since non-linearity produces signals additional to the
source signal ......



Well, I guess you know better than the folks who came up with RIAA & NAB
etc. curves - both grossly non-linear, to be linearized by the
reproduction
gear (which, ideally, has mirror-image nonlinearity).


** How smartarse.




When he says that no speaker (and presumably no microphone)......


** That is a BIG presumption. Microphones are way superior to
speakers in terms of response range, linearity and SPL handling. Mics
intended
for measurments can have flat response from DC to 50 kHz and handle up to
150
dB SPL at any frequency.


Errr... DC? I love the sound of DC... Are you sure you're not confusing
mics & barometers? Or altimeters? Which mics are you referring to? Give
me a link to the spec sheet?


** RF condenser mics have response to DC.




gets close to hi-fi, Arny consigns his whole edifice to obscurity. It
is
meaningless in the real world, and its central tenet cannot be tested.


** The imperfections of even the best speakers are easlily
indentified
and heard.


Uh Huh. I've got clients like you.


** The local mental hospital has inmates like you.



Your assertions are mindless, at best.



According to a recent discussion on microphone placement, if Arny
had his way I would end up sitting under the piano.


** If that is where you need to place a mic to capture the sound
pressure signal ....



"Sound pressure signal"? You don't mean fluctuations in barometric
pressure, do you?


** Wrong terminology.


If not, and the "sound pressure signal" is in the freq.
range of human hearing, i think there's a word you might enjoy using in
the
future, encapsulating every nuance of your (hopefully) intended meaning:
"SOUND".


** What a mic produces is an electrical signal derived from the varying
air pressure at a point in space. When you record that signal you "capture"
it.




Just a token resistance...I know Arny has heard it all before, and
is obviously committed to his cause come hell or high water.

I think we are into complimentary transforms here. Mess about until
it sounds right, then maybe measure for fun.


** Ok, who needs guys like Bill Shakespeare ?? - everyone knows
that a million monkeys at typewriters can produce the same stuff in no
time.


Who's Bill Shakespeare? Surely not William Shakespeare, who's informal
name
was *Will*? Your writin' is no match for his, or even The Typewriter
Monkey
Gang. You have a good one, heah?



** You are one demented ****head.





.............. Phil

"Phil Allison" wrote in message
u...

"Shiva" wrote in message
...

"Phil Allison" wrote in message
...

"Ian Iveson" wrote in message
...

This is where the whole Krueger/Pinkerton axis wobbles into
absurdity.


** You're looking a bit wobbly yourself, Ian.


Ad Hominem is da best kind'o argument.


** One ad hominem deserves another.




Which speaker should the load look like, and in which room?


** The one you intend to use would be a good place to start.


For evaluating an amplifier?


** Yep.



The simple reproductionist argues that, in order to achieve the
necessary linearity throughout the chain from the original sound
source to my room, each link must itself be linear.


** Well, since non-linearity produces signals additional to the
source signal ......



Well, I guess you know better than the folks who came up with RIAA & NAB
etc. curves - both grossly non-linear, to be linearized by the
reproduction
gear (which, ideally, has mirror-image nonlinearity).


** How smartarse.




When he says that no speaker (and presumably no microphone)......


** That is a BIG presumption. Microphones are way superior to
speakers in terms of response range, linearity and SPL handling. Mics
intended
for measurments can have flat response from DC to 50 kHz and handle up
to
150
dB SPL at any frequency.


Errr... DC? I love the sound of DC... Are you sure you're not
confusing
mics & barometers? Or altimeters? Which mics are you referring to?
Give
me a link to the spec sheet?


** RF condenser mics have response to DC.




gets close to hi-fi, Arny consigns his whole edifice to obscurity.
It
is
meaningless in the real world, and its central tenet cannot be tested.


** The imperfections of even the best speakers are easlily
indentified
and heard.


Uh Huh. I've got clients like you.


** The local mental hospital has inmates like you.



Your assertions are mindless, at best.



According to a recent discussion on microphone placement, if Arny
had his way I would end up sitting under the piano.


** If that is where you need to place a mic to capture the sound
pressure signal ....



"Sound pressure signal"? You don't mean fluctuations in barometric
pressure, do you?


** Wrong terminology.


If not, and the "sound pressure signal" is in the freq.
range of human hearing, i think there's a word you might enjoy using in
the
future, encapsulating every nuance of your (hopefully) intended meaning:
"SOUND".


** What a mic produces is an electrical signal derived from the varying
air pressure at a point in space. When you record that signal you
"capture"
it.




Just a token resistance...I know Arny has heard it all before, and
is obviously committed to his cause come hell or high water.

I think we are into complimentary transforms here. Mess about until
it sounds right, then maybe measure for fun.


** Ok, who needs guys like Bill Shakespeare ?? - everyone
knows
that a million monkeys at typewriters can produce the same stuff in no
time.


Who's Bill Shakespeare? Surely not William Shakespeare, who's informal
name
was *Will*? Your writin' is no match for his, or even The Typewriter
Monkey
Gang. You have a good one, heah?



** You are one demented ****head.



Phil, buddy, it's like this:
Try for any redeeming quality. Anything. Intelligence, knowledge, manners,
wit ... I dunno, *anything*. I'll check your posts from time to time, and,
as soon as you show a hint of promise, I'll ask one of the less-squeamish
RAT's to give you a *BIG* hug. Don't give up, now! Just Keep Punching,
Joe!
(This stuff don't happen overnight, so don't start replyin' right away, OK,
Champ?)
'luck,
-dim

"Shiva" wrote in message
...

Phil, buddy, it's like this:


** I am no buddy of yours.


Try for any redeeming quality.


** You are way beyond redemption.


Anything. Intelligence, knowledge, manners,
wit ... I dunno, *anything*.


** You "dunno" is the fact of the matter.




........... Phil