ROFL. Sorry to laugh at your misfortune, but still...
What software are you using?
Recone. You don't want it failing when you really don't want it to fail.
BTW - I've got an Alpine Type R12D2 that has failed in an unusual (for me) way - the plastic dustcap has developed cracks. No possibility of reconing that (sigh).
Using REW. I don't know if the software has a little bug or if its operator error, but whatever. Its now a bendy driver.
I can't decide between dismantling the driver so we can see what it looks like inside, or just burning it with some EDM.
Chris
Edit - gonna dismantle it. Burnt driver smell isn't nice.
I can't decide between dismantling the driver so we can see what it looks like inside, or just burning it with some EDM.
Chris
Edit - gonna dismantle it. Burnt driver smell isn't nice.
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I was running soundcard > QSC digital desk* > NU6000. Should've put a filter in on the desk. Really really should've.
* Only because the faders can be moved exactly - if the desk says 10dB, its 10dB. No messing with analogue faders and "close enough".
The supplier has got back to me, it'll be around £150 all done for a recone. That's what I paid for the driver, though they're more like £250 new.
Time to find some packaging...
I was hoping to test the output compression as higher powers were applied. Wasn't showing any obvious port compression when I did the last test.
FWIW, I passed the SPL meter's 130dB limit towards the end. This was indoors, though. Terms and Conditions apply.
Chris
* Only because the faders can be moved exactly - if the desk says 10dB, its 10dB. No messing with analogue faders and "close enough".
The supplier has got back to me, it'll be around £150 all done for a recone. That's what I paid for the driver, though they're more like £250 new.
Time to find some packaging...
I was hoping to test the output compression as higher powers were applied. Wasn't showing any obvious port compression when I did the last test.
FWIW, I passed the SPL meter's 130dB limit towards the end. This was indoors, though. Terms and Conditions apply.
Chris
Some pictures of the dead driver. I wouldn't've got to see this if it was still working properly.
First up, the folds:
Opened up. Interesting VC venting. The 3 holes in the top plate fire down towards the 6 holes directly below the voicecoil.
VC is two layers, one inside one outside.
Overhang looks around 9mm.
Spider is dual-layer.
Chris
First up, the folds:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Opened up. Interesting VC venting. The 3 holes in the top plate fire down towards the 6 holes directly below the voicecoil.
An externally hosted image should be here but it was not working when we last tested it.
VC is two layers, one inside one outside.
An externally hosted image should be here but it was not working when we last tested it.
Overhang looks around 9mm.
An externally hosted image should be here but it was not working when we last tested it.
Spider is dual-layer.
An externally hosted image should be here but it was not working when we last tested it.
Chris
Yep, that'll do it.
Expensive mistake, but I won't forget that one any time soon.
Cheers
Chris
Chris,
Mistakes happen, but when they are expensive, they do tend to be more memorable.
I have blown more speakers testing them than in over 40 years of mixing and listening, which kind of begs the question, "why do such rigorous testing, when I know what distressed speakers sound like, and turn them down before they ever are damaged?"
And "if a driver blows up in the forest with no-one there, did it make a sound?"
Cheers,
Art
This one sure made a sound, very similar to the sound of the coil hitting the backplate, but either the coil itself is made of sturdy stuff, or the suspension was locking up that badly.
Of course, W10 updated itself while I'd left REW open, so I lost the data from the dead driver.
I can say it passed 130dB @1m distance, though with the extremely high THD levels, that can be taken with a little salt.
There wasn't any port compression showing up - the response overlaid well when I added 10dB to the output and took 10dB off the mic feed. IIRC there was 1dB difference somewhere at the bottom end, but the driver had given up by that point.
I've trawled through the REW help file, and it does indeed state that the sweep goes from half of the lower frequency to twice the upper. Why not just sweep between the frequencies I ask for?! *grumble*
Chris
PS - the first proper speaker I blew was a nice RCF unit. I'd set the compressor-limiter so none of the amps were clipping, and then mashed right into the limiter. Combine that with a 600w amp (for a 350w speaker), and I'm amazed it lasted the 2-3 hours it did.
Of course, W10 updated itself while I'd left REW open, so I lost the data from the dead driver.
I can say it passed 130dB @1m distance, though with the extremely high THD levels, that can be taken with a little salt.
There wasn't any port compression showing up - the response overlaid well when I added 10dB to the output and took 10dB off the mic feed. IIRC there was 1dB difference somewhere at the bottom end, but the driver had given up by that point.
I've trawled through the REW help file, and it does indeed state that the sweep goes from half of the lower frequency to twice the upper. Why not just sweep between the frequencies I ask for?! *grumble*
Chris
PS - the first proper speaker I blew was a nice RCF unit. I'd set the compressor-limiter so none of the amps were clipping, and then mashed right into the limiter. Combine that with a 600w amp (for a 350w speaker), and I'm amazed it lasted the 2-3 hours it did.
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Probably because a hard turn on at the frequencies you ask for would leave the two measurement extremes "glitchy", while sweeping up from below, and past the upper frequency provides a "clean sweep", though that sweep could be a problem if the driver is not protected from mechanical damage with a HP filter.
This particular driver is one of the ones I've had for a few years, and its been on the end of an NU6000 sometimes driven right into clipping. I was quite impressed with the coil - I would have expected it to be a little discoloured.
Still, >500w of 15Hz in a cabinet tuned in the mid-30s will do that to pretty much any cone, I expect.
I can say that the rated 52mm p/p excursion before damage was very impressive to watch. Wish I had a video.
I've heard from the supplier, the recone is done and they're testing to make sure everything's working okay.
Chris
For such an 'old' abused driver it is remarkable that the coil looks this fresh. Most drivers I have reconed after a few years of use do not look like this, there always some discolorations noticeable.
REW can be quite brutal on drivers when doing sweeps. I always set the HP on my DBX at a reasonable setting that would not let the driver exceeds his lower limit.
You can also use a DB meter at same distance as mic position. And fill in the measurement in REW DB settings. The reading will be more accurate db-wise.
Yet... I see no need to do a sweep with 500w+
REW can be quite brutal on drivers when doing sweeps. I always set the HP on my DBX at a reasonable setting that would not let the driver exceeds his lower limit.
You can also use a DB meter at same distance as mic position. And fill in the measurement in REW DB settings. The reading will be more accurate db-wise.
Yet... I see no need to do a sweep with 500w+
I was testing for port compression, increasing the level in 10dB steps. I had planned on making it 2 or 3dB steps once I'd found where things start to give up. So, I did ~5w, 50w, both of which went okay, so added another 10dB without realising it was running at such a low frequency.
I can say it max'd out my SPL meter, which is good for 130dB C-weighted. The SPL meter was 1m away, so some room effects were likely present at that distance. The close mic (I actually used a kick drum mic that I EQ'd at the desk to give an identical response to a measurement mic at the same position. The kick drum mic is rated for 172dB IIRC) didn't show any compression at the tuning frequency when the driver gave up.
Chris
I can say it max'd out my SPL meter, which is good for 130dB C-weighted. The SPL meter was 1m away, so some room effects were likely present at that distance. The close mic (I actually used a kick drum mic that I EQ'd at the desk to give an identical response to a measurement mic at the same position. The kick drum mic is rated for 172dB IIRC) didn't show any compression at the tuning frequency when the driver gave up.
Chris
Driver's back from the supplier, everything looks shiny new.
However, Fs is coming up at ~48Hz (before the recone it was 38Hz), so some break-in will be required - the suspension starts locking up past a couple of mm of travel, and its pretty stiff to start with.
I'll be gentle with the sine waves this time, promise.
Chris
However, Fs is coming up at ~48Hz (before the recone it was 38Hz), so some break-in will be required - the suspension starts locking up past a couple of mm of travel, and its pretty stiff to start with.
I'll be gentle with the sine waves this time, promise.
Chris
Chris,
Don't molly-coddle a driver capable of handling several horsepower, follow Diamanda Galas' mantra and "Dominate your Electronics".
It's worked for us for the last 32+ years
.Art
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