In either case, you could either purchase an HPIB meter or a PCI-based meter, read the measured values in with Labview and have Labview send out tones as needed or required.

TTFN

Would not a voltage to frequency converter circuit followed by an audio amplifier stage be adequate?

-Pete

One thing that might help depending on how loud you need, is to set your fluke to "min/max" and it will beep whenever the current reading is above or below the latest min/max. So, let the meter sit for a few minutes and get a good minimum and maximum value then go tweeking and listen for the beep.

Thanks guys for the advices.
I had already think of a Labview app or a V/F circuit.
I'm more looking for an exisiting equipment I can use
and refer to my clients.
The Fluke min-max is a good idea also.
I'll try it.

Three thoughts:

1.  I like the frequency converter idea.  Even better, if you can mix in a reference frequency for the voltage you're adjusting to, along with the frequency that you're measuring, you could "tune" for the exact voltage by listening to the beat frequency, as you drifted further away you'd hear "wa-wa-wa-wa-wa" and as you got closer it'd change to "waaaaaah-waaaaaaaah-waaaaaaaaaaaaaaaah".  Beat counters could similarly be used that would give you a ticking sound like a metal detector or geiger counter.  Any old metal detector circuit would get you close.  Actually, you could probably hack a cheap metal detector pretty easily to build your circuit.

2.  For 12vdc (car audio), I used to use a multi-meter with a buzzer-type continuity detector, but use it to measure voltage.  You'd get a pretty good audible indication of voltage as the thing changed tone from a low "buzzzzzz" to "WHEEEE".  Yeah, they'd burn out after a while, but they were cheap and easy.  I don't know if this would give you the accuracy you're looking for.

3.  A Google search on "talking voltmeter" turned up an apparently obsolete Micronta model.  Maybe you could find one of those.  It also turned up the fact that Fluke played around with a prototype talking voltmeter too, but that it drove everyone nuts so they dropped the whole idea (words of warning to you?)

What kind of voltages are you working with?  What ranges of voltages?  How accurate do you need to be?

I like the idea of the continuity detector. I'll try it next week.
I also think that talking voltmeters are like talking cars. "The door is ajar" syndrom...

I have to align some optical components so that a laser beam finally reaches a photodetector. I'm measuring the output of the photodetector WHILE making adjustments that are very precise. So I cannot look at the voltage at the same time. Variation is from 0 to 2VDC. When the laser beam reaches the photodetector, I can fine tune whithout looking at the optics.