Diagnosing a speaker problem.

[DRC]

I am having an issue with the mid-range driver on one of my monitors. I thought I had a blown driver and ordered a new one. Installed it and it worked. After moving the pair to a different location I have noticed that the new driver now has 10% of the level that the other one does.

I checked every connection at the amp, at the back of the speaker, i took out the driver to make sure the clips were connected nice and tight, I switched the amps.... everything! Could there be a problem with the internal crossover? Do vifa drivers have to be calibrated or something? I am at a loss and need to get this taken care of soon.

[Granny Gremlin]

Bad driver (since new from factory) is unlikely. Vifa has good QC. Check the internal wiring in the speaker cabinet for shorts and blown caps in the crossover. Actually, most likely (considering youv'e checked everything else already)it could be phase cancellation between the drivers (am I correct in concluding from your post that you are using external amps driving passive speakers - hence passive crossovers?). If the cab uses 2nd order crossovers, the mid needs to be wired out of phase (+ve wire to -ve terminal on the mid). Otherwise check that you connected the mid in phase with the tweet and woofer - if you don't know how to check, just try switching the leads on the mid and see if that helps.

[David Kulka]

A few ideas:

Try the old driver in the good speaker, the one that has always worked. If it sounds ok, then obviously there was another problem all along.

There might be an intermittent problem in the crossover or in the wiring that temporarily cleared after you replaced the driver.

If you can, connect both speakers to the same amp output and send a 500 Hz or 1k tone into the amp input. Use a AM meter and measure the voltages at the terminals of each drivers. The voltages should be the same. If they are the same and the sound levels are different, you have a bad driver. If they are not the same the fault is probably inside the speaker. In that case, for further confirmation, you could swap drivers. If the voltages do not change, the problem is definitely in the speaker.

[DRC]

Thanks for the input guys. I did in fact take the mid-range out of the good cab and drop in the "bad" driver. It was the driver all along. Thank god it wasn't the crossover! Whether you can believe it or not, I was sent out a bad Vifa replacement originally before taking the matter into my own hands and ordering a new Vifa driver from a wholesaler....it was bad too! I can't speak for Vifa's QC, but when the components are working they do sound great.

The situation is being taken care of with a matched pair this week so I should have my speakers back by Friday. Thanks a bunch guys.

[tINY]

If both of the new drivers were "bad", perhaps the original one was a custom driver or the specs have changed....



-tINY

[DRC]

Originally Posted by tINY

If both of the new drivers were "bad", perhaps the original one was a custom driver or the specs have changed....



-tINY

That's what I was told, but I gotta tell you I find it hard to believe because the label and model # were the same. The driver I ordered (and have to send back here pretty soon) measured @ 4 ohms the first time, then 2 ohms the next time. Weird? It should all be taken care of pretty soon. The speaker company is going out of their way to make sure it gets corrected.