On November 11, 2019 at 12:59, buzz said...
What is the frequency response of the unit?
Actually, for many measurements I prefer an appropriate analog meter.
This is EXACTLY my point. If one duplicates the impedance measuring circuit I outlined above, a very accurate at low voltage levels meter -- and I mean AC, not DC -- is required.
At one point, in cooperation with a manufacturer, we held a "clinic". The national service manager came to town to participate. Early in the day he criticized me for not providing a DVM for the low level measurements. After he got to know the instrument, he admitted to liking my "old fashioned" analog meter. (1mv full scale, this was not a cheap meter)
The parenthetical comment is a very important point.
Yes, you can easily find a digital meter with four or five digits, but two or three of the digits are usually bumbling around, forcing one to mentally average the bumbling. An analog meter will automatically smooth over a little noise.
Yeah, but if your AC source is a power amp that can output 10 volts, the "little noise" is much littler than with a signal generator of some sort.
I'd love to hear from Fins as to why he wants to measure speaker impedance. It'd be a bit funny if all this discussion resulted from him wondering if there's a simple way to figure out if he's holding an 8 ohm or a 4 ohm midrange in his hand.
