speaker or crossover damage

evlah

Member
2007-11-14 8:18 pm
Hi,
I'm hoping someone may be able to provide me some insight...
Well, is it possible to damage your speakers or crossover by shorting lets say the right and left rca input of an amplifier while the amp is still on and connected to the speakers? and if so where should one look for repair? I'm saying this cause i accidentally shorted a pair of interconnects while swapping out cd players and had forgotten the amp on. Heard a static noise from the speakers for a couple secs... Speakers seem to still be working but they dont really sound the same when playing cds using the same setup as before fiddling with the cdp.
They seem to sound thin, Bass just doesnt sound the same as before dunno kind of wierd to describe but its driving me nuts...
Any help will be greatly appreciated.

Evan
 
You posted this somewhere else, and I answered there, but I can't actually remember which forum.

There, assuming you are the same person, you said you shorted the signal line of the RCA to ground/chassis. Here, unless I am mistaken, you are saying to shorted the center signal line of one RCA to the signal line of the other channel RCA.

Either way, the signal to the speaker would have to be mammoth to do any damage. I can't say it didn't happen, just that is seems unlikely.

If your amp has a MONO button, set it to mono and play some music. Listen, just inches away, specifically to the woofer, mid, and tweeter. See if you can hear a difference between the left and right.

Steve/bluewizard
 

tinitus

diyAudio Moderator R.I.P.
2005-11-24 1:47 am
NEVER mess with interconnects with the power on :smash:

I am no expert on this matter, but I maybe its your electronics you should worry about, you might have upset something

About your XO...if there is low voltage electrolytics in your, they might have failed...hard to say, but I suppose its possible, allthough they should handle quite more than their ratings fore a second or two
 

BlueWizard

Member
2007-06-29 8:49 pm
Software Recommendations

Evan and I are discussing this problem in another forum where I mentioned the availability of speaker testing software.

Would anyone here be willing to make some recommendations for free speaker testing software. Something that will generate tones or 'noise' and create a frequency response graph, and an impedance graph.

Also, does anyone know of a source and the model numbers of the raw condense mics that most people are using? (Pansonic, I thought)

Can anyone recommend a commercially available mic at a reasonable price?

Also, there is a test box, with various resistors and connectors for testing speakers (usually impedance testing), could someone provide links to that box design.

And finally, could anyone provide the names of good free speaker modeling and testing programs. I've already given Evan links to WinISD, ARTA/Steps/Limp, Basta, and Edge. Any opinions on these programs?

Thanks for the help.

Steve/bluewizard
 

Iain McNeill

diyAudio Moderator Emeritus
I've used Panasonic WM-60AY before but it's now a non-stock item at Digikey. The WM-61A has better SNR (>62dB) but with it's higher sensitivity, the actual noise output is higher than the 60AY. Its omnidirectional, puts out -35dBV/Pa (±4dB - probably closer to 6dB in reality) and should be pretty flat over most of the audio range. You just won't know the actual calibration so no good for speaker sensitivity measurements but just fine for frequency response etc.

All this for $1.86 +tax+shipping from Digikey P/N P9925-ND
 

BlueWizard

Member
2007-06-29 8:49 pm
I stumbled across a couple more places to get Speaker Design and Testing software.

There is definitely a learning curve here, but if you are interested, if might be a nice intro to Do-It-Yourself Speaker building.

Speaker Workshop-
http://www.speakerworkshop.com/index.htm

Jeff Bagby's Loudspeaker Design Software -
http://audio.claub.net/software/jbagby.html

Frequency Response Data Consortium -
http://www.pvconsultants.com/audio/frdgroup.htm

No denying some of this software is over my head, but you learn by doing.

Steve/bluewizard
 

BlueWizard

Member
2007-06-29 8:49 pm
evan,

Don't know if you are still checking back here, but here is a link to a relatively low priced commercial microphone that would work for testing speakers.

Behringer ECM8000 Measurement Microphone - $49.99 EA
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=248-625

Here is a link to the Behringer website. On the right of that page is a link in the 'Download' section to the Spec Sheet for the mic (PDF format) and a link to an 'instruction' sheet (also PDF).

http://www.behringer.com/ECM8000/index.cfm?lang=eng

Just trying to help.

Steve/bluewizard
 

Bobken

Member
2002-12-23 11:22 pm
UK
Hi Evan,

From what you say and from the sensible comments from BlueWizard in post #2, I would guess that it is far more likely that you have damaged the amp in this case, than the speakers.

Unless somehow the amp put out a huge DC voltage, or similar, which I would have thought you would have heard as much more serious than some 'static noise', it is hard to think that much harm would have come to the speakers, but it is not possible to be certain about this. Shorting the 'hot' inputs of an amp to ground shouldn't do any real harm, but possibly shorting across the inputs (as has been suggested) might cause a problem within the amp, depending on the internal circuitry layout.

So, before you go too far down the road of considering speaker-testing equipment, if you haven't already established beyond any doubt where the damage occurred, I would check this out first.

Have you tried another amp with these speakers to see what happens, or maybe tried your amp with some other speakers?

Regards,
 
Got me wondering ...

Did I do the same thing?

I frequently test new drivers with just bare wire ends wrapped on speaker terminals. I'm not real careful regards connections.

Did so a couple weeks back and next thing I knew my PIO 5.1 HT shut down and started flashing 'power off'.

I've tested driver with other amp and it works fine. Tested amp with other drivers and signal remains. Did vibration possibly cause hot and negative to touch and short my box? I would have thought circuit protection built in.

Likely I fried it or something worth fixing?

In the future I'll at least put some spade plugs on.

Thanks

Bluto