inexpensive analog audio pitch (frequency?) meter or schematic /plans for one?

[[email protected]]

I am looking for an inexpensive (hopefully $20 or less) analog meter

one with a moving needle like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg

that I can plug my computer's sound card into (actually two meters,
one for the right speaker, one for the left), that will read the pitch
of the audio being played.

I know that a given sound has a fundamental tone and overtones, and it
would have to detect the fundemantal tone (like a guitar tuner). The
audio source would be a MIDI program, so if necessary I could use
samples of a very simple waveform (ie Sine, square, etc) if that would
eliminate overtones and make pitch detection more accurate.

Does anyone know if such a meter exists or where to find plans to
build one?

Thanks.

 

[whit3rd]

I am looking for an inexpensive (hopefully $20 or less) analog meter

... that will read the pitch
of the audio being played.

Phase-lock loops like 74HC4046 can lock onto an audio
frequency, and the follower in it has an output voltage
proportional to frequency. That's about $0.60 from your budget;
a good analog moving-needle meter will suck up the rest of it.

 

[William Sommerwerck]

You can buy digital (yes, I know you said you wanted analog) autotuners --
such as those from Sabine -- for around $30.

 

[[email protected]]

Thanks for your reply. I am not skilled in electronics - do you know
of any schematics I could follow to build one of these?

 

[William Sommerwerck]

I am not skilled in electronics -- do you know of
any schematics I could follow to build one of these?

If you're not skilled in electronics, you're wasting your time. Buy a
commercial unit and be done with it.

 

[DaveM]

I am not skilled in electronics -- do you know of
any schematics I could follow to build one of these?

If you're not skilled in electronics, you're wasting your time. Buy a
commercial unit and be done with it.
[/QUOTE]

Go to a music store (one that sells musical instruments) and ask for a tuning
meter. Korg is a brand many stores carry.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

"In theory, there isn't any difference between theory and practice. In
practice, there is." - Yogi Berra

 

[Richard Crowley]

Thanks for your reply. I am not skilled in electronics - do you know
of any schematics I could follow to build one of these?

Maybe. What do you want to do with it?
Can't answer it as a generic question. It
seems absurd to even think about a "meter"
for frequency when listening to most any
kind of normal audio.

(posted from: rec.audio.tech)

 

[William Sommerwerck]

In fairness to the original poster... Once upon a time you could buy Heath
or Knight or EICO or other electronics kits, to save money, learn about
electronics, or just have fun. Most currently available kits don't do much
useful and are overpriced.

 

[Spehro Pefhany]

If you're not skilled in electronics, you're wasting your time. Buy a
commercial unit and be done with it.

Go to a music store (one that sells musical instruments) and ask for a tuning
meter. Korg is a brand many stores carry.[/QUOTE]

Lots (mostly digital with faux analog displays) to pick from for
between $10 and $20. I just bought this one at a local music store for
$15 or so, batteries included.

http://www.amazon.com/KORG-GA30-Gui...8&s=musical-instruments&qid=1199494627&sr=8-8


Best regards,
Spehro Pefhany

 

[William Sommerwerck]

Lots (mostly digital with faux analog displays)...

Good grief. One of those rare human beings who actually understands the
difference between analog and digital. Congratulations!

 

[Wim Ton]

I am looking for an inexpensive (hopefully $20 or less) analog meter

one with a moving needle like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg

that I can plug my computer's sound card into (actually two meters,
one for the right speaker, one for the left), that will read the pitch
of the audio being played.

I know that a given sound has a fundamental tone and overtones, and it
would have to detect the fundemantal tone (like a guitar tuner). The
audio source would be a MIDI program, so if necessary I could use
samples of a very simple waveform (ie Sine, square, etc) if that would
eliminate overtones and make pitch detection more accurate.

Does anyone know if such a meter exists or where to find plans to
build one?

Thanks.

If you have a computer anyway, how about using the sound input and run
one of the numerous spectrum analyser programs on it?

Wim

 

[William Sommerwerck]

I know that a given sound has a fundamental tone and overtones,
and it would have to detect the fundemantal tone (like a guitar tuner).

There's no need to "detect" the fundamental. The device would simply look
for zero crossings, which are the same regardless of the presence or absence
of harmonics.

In fact, I'm reasonably (but not completely) sure a PLL would work with a
non-sine signal.

 

[MooseFET]

There's no need to "detect" the fundamental. The device would simply look
for zero crossings, which are the same regardless of the presence or absence
of harmonics.

That need not be true. If you have a large high harmonic, you can
have two zero crossings where one is expected. Only a little
cleverness is needed to fix the problem.

In fact, I'm reasonably (but not completely) sure a PLL would work with a
non-sine signal.

They do but you need to make sure that they sweep up to the frequency
they are going to lock onto. Most PLL designs will happily lock onto
a harmonic.

 

[Rich Grise]

Good grief. One of those rare human beings who actually understands the
difference between analog and digital. Congratulations!

There are 10 kinds of people in the world:

Those who understand binary, and those who don't.

;-)
Rich

 

[jack]

National Semi still makes a "frequency to voltage" converter chip, so does
Analog.

But here's a link to using a PLL -- from National Semi -- Application Note
210
http://www.national.com/an/AN/AN-210.pdf

 

[William Sommerwerck]

National Semi still makes a "frequency to voltage" converter chip,
so does Analog.

But here's a link to using a PLL -- from National Semi --
Application Note 210
http://www.national.com/an/AN/AN-210.pdf

This is fine, but what about the accuracy and resolution of the analog meter
used to read the output?

It still isn't clear why the OP is insisting on an analog display.

 

[Richard Crowley]

"jack" wrote ...

National Semi still makes a "frequency to voltage" converter
chip, so does Analog.

But here's a link to using a PLL -- from National Semi --
Application Note 210
http://www.national.com/an/AN/AN-210.pdf

Note that publication is 29 years old and I don't think any
of the mentioned ICs are still in production any more.

 

[msg]

"jack" wrote ...



Note that publication is 29 years old and I don't think any
of the mentioned ICs are still in production any more.

Since when has that stopped real homebrewers? Ahh, I see a slew of cross-
posted groups (reading from r.r.a.h)

Michael

 

[Richard Crowley]

"msg" wrote ...

Since when has that stopped real homebrewers? Ahh, I see a slew of
cross-
posted groups (reading from r.r.a.h)

Don't get me wrong. I am working on a couple of projects
that could use circuits like that, but they are simply not
produciton-worthy anymore. :-(

 

[[email protected]]

Thanks to everyone for your replies. I just want to do analog metering
with moving needle meters. I am aware that to meter volume/frequency
digitally, I can buy a mixer or tuner, or via computer with the
appropriate software. The meters in question are from an old Radio
Shack mixer (I'll have to find the model #, left it at home). No
matter what the exact specs of the meters however, the basics of the
circuit for metering volume or pitch/frequency should be the same.
Thanks again.