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How to figure out speaker sensitivity

N

Normando

New Member
I have an old pair of EV esquire 200's and despite reading everything I can find on line, I can't find out what their sensitivity is. Is there a formula that lets you calculate what the sensitivity is, and is so, what parameters do you need to know to do that? Thanks Norm
 
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I believe I've read somewhere that the Esquires are 102db/1w. As to a formula - well - get a SPL meter (an app on an iDevice might be good enough) and giver 1w - then see what SPL you hit. Not exactly scientific, but I bet you'll be well within the ball-park.
 
If they are that sensitive then I would advise a slightly different way of measuring. The standard is a 1000 Hz tone and at 102 dB that would be VERY loud. (My bathroom fans measure out at 75 dB and they are annoyingly loud).

I suggest a much weaker signal. Say about 1/10 watt. For an 8 ohm speaker that is ~ .9 V rms. For a 4 ohm speaker that is ~ .63 volts rms. Measure the output at that voltage at 1 meter, ~ 39 inches. Add 10 dB to that number and you have it.

If that is too loud and you are afraid of speaker damage then use ~ .28 volts for 8 ohms or .2 volts for 4 ohms. Then add 20 dB to the reading.

Shelly_D
 
I have a small formula that can calculate it, but it's only for raw drivers, not a whole speaker system, and you need the Fs, Vas and Qes specs.
 
All you need is an spl meter and an amp with output meters. Stand 3 ft. from the speaker and take a reading at 1 watt continuous on the amp meters.
 
I doubt that the Esquire is that sensitive, but it is pretty sensitive fo' shizzle.
I'd guess mid to high 90s, assuming it's 8 ohms (that's something else I am not entirely clear on vis-a-vis the Esquires).

Why do you want/need to know?
 
Why do I want to know? I am trying to decide whether to have an old tube amp restored and having sensitive speakers, since it is low wattage amp , would probalby be a better fit. I don't want to have to go and find some other dusty treasure at a yard sale and hope it would mate well with a tube amp. Norm
 
Well... the short hand for this is 50/60's tube amp - look for 50/60's speakers. Not 100% fool proof - but good 'nuff. The assumption being that engineers for both products built to what was available at the time.
 
sealy said:
All you need is an spl meter and an amp with output meters. Stand 3 ft. from the speaker and take a reading at 1 watt continuous on the amp meters.
Click to expand...
I would add to this recipe another speaker that is of known sensitivity for the purpose of calibrating your setup.
 
Ok.

So... Using a free app on my iPad... running a 1K tone check from one of my tuners... and using my Realistic APM-100 to set the power to 1W... With the iPad mic pointed at the speaker and situated 3 feet from and 3 feet up...

I got 96 DB out of the Esquires.

Looks like Mark is right yet again. The Esquires are efficient, but no where near 102.

So there you are with my completely unscientific measurement.
 
And the Esquires work - IME and IMNSHO - very well with, e.g., single-ended 2A3 (3.5 watts) and reasonably well with triode-wired single-ended EL84 (ca. 2 watts). Might not be ideal for SE 45 amps (2 watts) or less... but pretty durned good with most reasonable low- to flea-powered amps.

Whaddya got, OP?

EDIT: The modern sensitivity rating is typically at 1 meter (39.37 inches), not 3 feet (not that 3 and a third-ish inches is a huge deal).
The old EIA sensitivity spec (which you will find for 1950s/1960s EV component drivers in the "EDS" datasheets, was for SPL at forty feet.
 
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