prevention help
hemihem
Posts: 8
I recently had 3 hf driver killed 2408H, I want to prevent this from happening ever again if that is possible:
JBL tech stated the coil were burnt on 2 of them therefore will not warrant
the other they warrant the repair, with this system I would have thought the days of burnt HF drivers were over, but I guest not.
2 Xs 700 bridge on 2 MRX515
what should the limiter, xcross point be set at to avoid this?
so that is 1 crown Xs700 bridge mode connected to 1 JBL MRX515
DRPA, with american audio mixer and DCD1000 cd player
ps cross over was LP 80HZ
guess I better give the complete system for the best answer, although there's no problem on the low freq end, but just for giggles
system is triamp, 1 bridge Xs700 on right to MRX700 connected to the drpa left high out, the other to the right high out,
Xti4000 on the low MRX528 hp40hz to 80hz
1 qsc 1202 bridge on mid, out from DRPA Xcross 80hz on monitor connected to MRX515 when needed only.
JBL tech stated the coil were burnt on 2 of them therefore will not warrant
the other they warrant the repair, with this system I would have thought the days of burnt HF drivers were over, but I guest not.
2 Xs 700 bridge on 2 MRX515
what should the limiter, xcross point be set at to avoid this?
so that is 1 crown Xs700 bridge mode connected to 1 JBL MRX515
DRPA, with american audio mixer and DCD1000 cd player
ps cross over was LP 80HZ
guess I better give the complete system for the best answer, although there's no problem on the low freq end, but just for giggles
system is triamp, 1 bridge Xs700 on right to MRX700 connected to the drpa left high out, the other to the right high out,
Xti4000 on the low MRX528 hp40hz to 80hz
1 qsc 1202 bridge on mid, out from DRPA Xcross 80hz on monitor connected to MRX515 when needed only.
0
Comments
Further, you are obviously running a VERY loud hi frequency section,(2000hz up) since the horns fried and the woofers did not...Those hors had to be \"Killin in the name of\"...Try getting the system FLAT... as in the RMFBP section...
Gadget
P.S. if you want speaker protection that you can't screw up... the 260 would have been a good bet...it has brick wall limiters... the DRPA does NOT!
DRA
Do you Auto-EQ rooms before you play?
What does the EQ graph look like?
What do the EQ knobs on your mixer look like?
Using the \"sound enhancement\" button on the mixer?
DRA
thanks in advance.
compression off, no clip was indicated on the mixer / no red zone
was not monitoring the drpa.
what is the idea situation settings? As from what I can tell running Xs700 bridge at 8ohms equal 1645 watts, is or should be more than enough for the MRX515, two speakers two amps. What would prevent this from happening again is my question, what should my DRPA setting be?
mrx are cross at 80hz recommended cross is 65hz, since I don't need any bottom from them they are cross at 80hz, to 1600khz bw24,
Mixer equal american audio q span pro
We are trying to help. We can only do that if we have good info. Please add anything else that could help us.
DRA
Now, with simply that info given and nothing in response to Dra's post I'd ahve to say that you used too much of that 1645 watts...What we are trying to get to here is the mechanism of injury... just like a doctor, you have told us precious little about what you have done, what settings you use, what EQ graph looks like, how loud you were playing when the damage occurred, were the speakers sounding HARSH before the damage occurred... Those are only 1.5\" diaphragms on those drivers...those should be crossed about 2500 hz if your going to play loud...but... JBL uses 1700 hz, Those speakers are only supposed to continuous power... 350 watts.. program 700 meaning for all practical purposes your average power fed to the speakers should be no more than the 350-700 watts specified... the PEAK power of 1400 watts would apply only for live music situations where an INSTANTANEOUS peak hits that level.
Look, Pre recorded music is HEAVILY compressed to beginwith, meaning it's AVERAGE is on the high side when compared to live... dynamic music...add to that the widespread use of MP3's and computers to deliver the music, and you have suffered even more in the dynamic music department...
You simply applied too much power for too long a period to the speakers and they literally cooked from the heat of the excess power. To much power kills speakers, too little can d o it as well, but only when the amp is called upon to provide more than 2x it's rated output and the duty cycle exceeds 50%, which excessively heats the voice coils. The smaller the diaphragm/voice coil, the less the coil can dissipate...simple as that...
Now if your going to come back and tell us the rest of the story, and why our theory of too much power didn't likk the speakers then you begin to see why we ask that you read the READ ME FIRST BEFORE POSTING where in one of the FIRST sentences it asks for ALL the pertinent information... or you WON'T get an answer...
Gadget
site moderator...
Do you Auto-EQ rooms before you play?
What does the EQ graph look like?
What do the EQ knobs on your mixer look like?
Using the \"sound enhancement\" button on the mixer?
I thank you Dra
I'm a professional D.j. since 1987, been trying to acheive the ultimate mobile d.j. system since that time, went through alot of products before settling with Crown and JBL, american dj that my money could buy.
my system I try to keep as clean as possible, which is something I've learned through the years and as such although I have EQ access, I don't use, I do use the adjustment knobs on the mixer to either enhance the treble, dull the mids, and ocassionally kill the base during mixes.
I had the MRX since MAY 2007 never a problem
complete system consist of
from top to bottom
American Audio Qspan pro
American Audio Velocity or DCD dual pro audio cd player depending on the event indoor or outdoor
DRPA configure 2x3 which I use the mid as a monitor when needed
I don't recall the complete setting that I have dial in, but I can asure you that the limiter was on as well as the AFS, XOVER is as stated above
2 Xs700 both bridge 1645 watts at 8 ohms one for each MRX515 8 ohms( 1 QSC 1202 bridge 700 at 8ohms bridge for monitoring duties when needed only) connected to the third MRX515
Xti4000 conneted sterio 4ohms 1200 watts to MRX528(2) 4 ohms per channel
I'm asking with the equipment listed what shoud the recommend setting be, if it was your system? your professional opinon? I aready paid for the repair, now time to relook what I have and prevent it from happening again. Obvious you can always learn and that's why I'm here to learn.
If you have not done an outdoor \"flattening\" session... do it.
X-over:
sub HPF 45hz BW18 LPF 90hz LR24
Top HPF 90 - 94hz
Amp - cab option
XTi4000 stereo (650w/8 ) - MRX515 (800w prog)
XS700 bridged (1900w/4) - MRX528 (2000w prog)
XS700 bridged (1900w/4) - MRX528 (2000w prog)
This set-up would give you (as long as the gain structure is properly set and clipping NEVER happens) a never fail system.
DRA
The DRPA does NOT have peak stop limiters...which means if you were using them you could well have exacerbated the problem WITH the limiter (higher average power levels)on.. you burned the tweeters with too much power...simple as that...you feed too much power to those tops. I don't like to run into the limiters... were you?
I wonder what happened to the third diaphragm? Did it fail @ monitor duty?
If you have the measurement mic it would be a good idea to see what is happening around the 1700 hz crossover region with those tops...if you didn't get any with the diaphragms.. some ferrofluid can help save those diaphragm's by dissipating power/heat.
The 260 has peak stop limiters, the DRPA will allow peaks to pass.. the harder you hit them the more that gets through the higher the average power...the smoke gets out.. and you can't get it back in...
Any more questions?
G
I don't know what happen other than the obvious, milk spilled, clean up and move on.
Again many thanks
Dra, Gadjet and all that contribute