Mike Rivers wrote:
Phil Allison wrote:
** To me it seems strange that instruments intended for
engineers and service techs to use for all kinds of electronic
work have such poor AC response.
I'm sure that there are still laboratory-grade digital multimeters that
cover the audio band,
** It's a basic requirement that analogue multimeters can all do.
Most analogue multimeters cover at least the audio band and beyond,
so if you can hear a sound coming from a loudspeaker, the meter
will measure the signal
True, but a decent one is more expensive than a digital multimeter,
** No, they can all do it.
Makers decided to "penny pinch" early DMMs, simply not mention the limited AC bandwidth and got away with it. So called True RMS models are usually no better for the same reason.
In the 1950s and 60s, the standard bench instrument for professional techs and engineers was a VTVM like this one:
https://www.radiomuseum.org/r/rca_se...st_wv_98c.html
I have one of those on my workbench, and it still works.
** Excellent.
For my article, I was reluctant to suggest buying a 50 year old analog
meter that could handle the full audio range, for fear that I'd soon
have to write an article about repairing antique test equipment. 
** The only hard to get / repair item is the moving coil meter itself.
12AU7s and 6AL5s are cheap & readily available, the 10uF PSU electro and selenium rectifier might need replacing.
BTW:
Ever try to test the resistance of a speaker in a noisy room with a DMM ??
Do you know what happens?
..... Phil