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First damage. B&C DE500

Printed From: Speakerplans.com
Category: Plans
Forum Name: Punisher and X-tro
Forum Description: Discussion / Questions about the Punisher and X-tro
URL: https://forum.speakerplans.com/forum_posts.asp?TID=94725
Printed Date: 18 October 2019 at 7:58am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: First damage. B&C DE500
Posted By: mirenkoo
Subject: First damage. B&C DE500
Date Posted: 13 February 2016 at 10:09am
After few years of running this lovely system first damage occurred. Xtro settings set as in plan.
Any idea why this happened? Amplifier used QSC RMX850.






Replies:
Posted By: VECTORDJ
Date Posted: 13 February 2016 at 12:47pm
Too much stress. Feedback??  Amp turning on/off thumping?? Do you use a cap ( 10 - 20 mfd) between the amp and driver??  VECTORSONICS


Posted By: Steve20131
Date Posted: 13 February 2016 at 6:18pm
Coils not burnt.  Looks like metal fatigue/old age?


Posted By: sn95
Date Posted: 13 February 2016 at 10:04pm
Originally posted by Steve20131 Steve20131 wrote:

Coils not burnt.  Looks like metal fatigue/old age?
+1


Posted By: MattStolton
Date Posted: 13 February 2016 at 10:20pm
I have had this reoccuring on some Tannoy V15i cabs. They are run passive, but part of a active 2 way FOH.

DSP is set exactly as per settings in manual, and has look ahead limiters, and huge amount of limited headroom on amps. My opinion is low res mp3, rich in unnatural harmonics, creating square waves at HF.

Either that, or the Tannoy designed and built X-over's are crossing at too low a frequency, or at too low a rate per octave.

I would expect similar from these identically failed diaphragms.


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Matt Stolton - Technical Director (!!!) - http://www.wildingsound.co.uk" rel="nofollow - Wilding Sound Ltd
"Sparkius metiretur vestra" - "Meter Your Mains"


Posted By: mirenkoo
Date Posted: 08 August 2016 at 9:55pm
Coil is absolutely fine. Maybe switching off other equipment first instead of amplifiers? Not expensive repair, but still... Speaker is 5 years old. 


Posted By: mirenkoo
Date Posted: 08 August 2016 at 9:57pm
Possible equipment switching on/off before amps. And no, no cap used between. Ill probably add them.


Posted By: Peter Jan
Date Posted: 08 August 2016 at 10:40pm
This damage is typical for a diaphragm that ran too low a frequency.


Posted By: mirenkoo
Date Posted: 09 August 2016 at 12:15pm
Even when crossed at 2500Hz? Using DCX2496.


Posted By: odc04r
Date Posted: 09 August 2016 at 1:24pm
Maybe, what slope?


Posted By: shaun1264
Date Posted: 09 August 2016 at 6:50pm
Some amps chuck out some DC when switching off.   Crackle and pop are some of the sounds.


Posted By: Teunos
Date Posted: 09 August 2016 at 7:30pm
Which is exactly why i run all of my HF drivers behind a very big (Fc at least an octave below intended Xover frequency) MKP capacitor.

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Best regards,
Teun.

,,Diamonds are forever''


Posted By: fatfreddiescat
Date Posted: 10 August 2016 at 2:12pm
To me that looks like it could be due to running high amounts of boost in the 8K plus region where the diaphragm is no longer working in piston mode, but is flexing. Often if the diaphragm has hit the bung hard, you can see the marks on the diaphagm


Posted By: ceharden
Date Posted: 10 August 2016 at 2:31pm
Originally posted by fatfreddiescat fatfreddiescat wrote:

To me that looks like it could be due to running high amounts of boost in the 8K plus region where the diaphragm is no longer working in piston mode, but is flexing. Often if the diaphragm has hit the bung hard, you can see the marks on the diaphagm

That's entirely possible.  More unusual on small compression drivers but seen it happen on large format ones where people have boosted them to try and produce frequencies they just can't do.


Posted By: studio45
Date Posted: 10 August 2016 at 3:21pm
After "several" years, I would say you've probably just hit the MTBF (mean time between failures). 
Titanium is nearly magic, but not quite. A certain amount of flexing, and consequent work-hardening of the material, is a normal part of operation - and when the hardness goes past a certain point, poof! Metal confetti. 
If you were shattering them every month, you would be doing something wrong. Once in several years is not really anything to worry about though. Apart from having to buy a new diaphragm at B+C prices of course ;)


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Studio45 - Box Builder Commotion Soundsystem -Mobile PA


Posted By: ceharden
Date Posted: 10 August 2016 at 3:53pm
B&C prices are a lot more reasonable now Blue Aran have taken over distribution. Proel were completely useless.



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