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tweeter testing guidance sought

J

Johnny7

Member
I recently had a bit of an accident with a silk-domed Peerless tweeter out of a late 70's Polk Audio loudspeaker.

The dome (miraculously) survived the drop unscathed, but now I'm wondering about the magnet/voice coil.

I want to test it - I have access to a Siglent frequency generator, but my question is: do I need a capacitor between the AWG and the tweeter? And if so, what uF and power rating?
 
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Why no amp in the chain? Can the generator actually deliver enough current to drive the tweeter?

The point of the capacitor is to block the low frequencies that the tweeter can't reproduce well or at all. Just use a frequency well within the tweeters range, something like 2kHz and above.
 
Can you reinstall if in the speaker crossover? If yes, do so and play some music. Use a paper towel or toilet paper core held up to your ear and the tweeter to see what you hear.
 
Johnny7 said:
@RVT1K, @BmWr75 - thanks for chiming in -- neither are options (else I would have pursued those)
Click to expand...
The simplest test would be to check the tweeter for continuity using a Volt Ohm Meter (VOM), should be in the 4-8 ohm range most likely. The VOM will reveal if the voice coil has gone open (infinite resistance) or shorted (much lower resistance than expected).
 
Did a DMM test already - checks out fine - before rebuilding these crossovers and reinstalling everything, I'm trying to determine if the drop caused misalignment of VC.
 
RVT1K, above, has the guidance. The caveats are -
1) The generator needs to supply enough current to drive the tweeter to reasonable levels.
3) Sweep or check at multiple points in the tweeter's bandwidth.
2) Don't go below 2kHz or so. If you're paranoid, you could use an 8uf non-polarized cap in series to block any accidental excursions into forbidden territory!
 
Have you tested the tweeter with a AA battery to see it function? A analog meter not a digital will be the preferred method to force the voice coil in and out looking for binding or other issues.
Doing a visual inspection of the mounting may be all that is needed if the tweeter functions with the 1.5 V applied.
 
I have not -- I'm really only trying to get advice on the exact setup I asked about. I want to hear it across various frequencies to check for any audible evidence of a shift due to the fall. BTW - the tweeter is not an unknown quantity -- it worked flawlessly before I took it out during a crossover rebuild.
 
To test the frequency yes a cap will protect it from being damaged by any low frequencies.

I would think a 4uf bipolar would be sufficient.
 
Since an amp is not an option, you could modify a 3.5mm cable so that you could drive the tweeter with the headphone output of your phone. There are lots of apps that act as tone generators. I suspect that will deliver a bit more current than a signal generator.

I used my phone and a tone generator app to test my speakers/crossovers during the build. I did use a small Bluetooth amp but fed 100hZ, 1kHz, and 10kHz tones to test the woofers, mids, and tweeters respectively.
 
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