Blowing Speakers

Bill@LakeGeorge · « **on:** 15 Nov 2003, 11:08 am »

I have Parasound C2 and A51 amp 250 watts/ch and Denon 2900 I keep blowing the woofers on Onix Ref2's. Which I believe are 4 ohm speakers rated at 300 watts

I have the speakers set to small. They seem to blow when playing DVD concerts somewhat loud, but certainly not deafining.

Could there be a problem with the amp? Any ideas?

theint · « **Reply #1 on:** 15 Nov 2003, 02:37 pm »

Is it possible that your amp is rated for 250W into 8 ohms and much more into 4 ohms such as 400w plus? If this is the case you may be over powering your speaker and you amp is damn good.

Bill@LakeGeorge · « **Reply #2 on:** 15 Nov 2003, 03:05 pm »

I am sure the amp is rated at 250 watts into 8 ohms and probably more like 400 into 4 ohms, but I didn't have cranked up like I could.

rkapadia@ROOP · « **Reply #3 on:** 15 Nov 2003, 04:12 pm »

Bill,

"Distorted" power will cause a speaker to blow out much more easily versus clean power. It also takes far less of the former to ruin a speaker cone. I'm not familiar with your amplifier, but I haven't known Parasound to produce amplifiers to clip as far below their rating as would have to be the case here.

Do you have a Radio Shack SPL meter handy? How loud would you guess?

Regards,

Rupesh

Mad DOg · « **Reply #4 on:** 15 Nov 2003, 08:06 pm »

how loud is loud? we need specs...

to a deaf person, 120dBs won't be loud... 120dBs to us, well that'd make us deaf!

Bill@LakeGeorge · « **Reply #5 on:** 17 Nov 2003, 11:39 am »

I checked last night with a Rat Shack meter and I believe they blew about 95db.

IanATC · « **Reply #6 on:** 17 Nov 2003, 12:39 pm »

Quote from: Bill@LakeGeorge

I checked last night with a Rat Shack meter and I believe they blew about 95db.

HMM and double hmm...

1) Was the speaker demonstrating any audible cone breakup or distortion before it gave way?

2) Did the cone(s) bottom out at any time? (click/raspy sound)

3) Was everything wired in polarity?

4) Are you sure that the speakers rating is not 300 watts peak vs RMS?
IE: 100 watts continuous/300 watts peak

5) IS there a chance anything was shorted togeather...even slightly?

6) Do you have any kind of tone control/eq with the bass turned way up?

That's all I can think of before my afternoon tea...

Good luck

Cheers

WerTicus · « **Reply #7 on:** 17 Nov 2003, 03:32 pm »

you would think the amp was clipping to blow a woofer... i would say there is something definatly faulty here.

Cause in all honesty with 250w channel of power it would take hearing damaging volume to clip the amp (i have 250w a channel too so i know) maybe the woofers are junk and arnt really able to handle as much power as you think/ they say.? that would be my guess, unless there is something WRONG with the amp.

rosconey · « **Reply #8 on:** 17 Nov 2003, 05:39 pm »

try them on another system and see what happens

theint · « **Reply #9 on:** 18 Nov 2003, 12:51 am »

Watch your woofer and see if it is being pushed forward or pulled back constantly. It may be possible that there is a DC offset coming from your amp.

Mad DOg · « **Reply #10 on:** 18 Nov 2003, 08:26 am »

Quote from: Bill@LakeGeorge

I checked last night with a Rat Shack meter and I believe they blew about 95db.

strange..i've had the ref 1s up around 95dBs and over and the only time i blew a woof was playing the 1812 overture...definitely operator error that time...

how far away from the speakers was the 95dB measurement taken?

Mad DOg · « **Reply #11 on:** 18 Nov 2003, 08:43 am »

bill,

just thought of this...

are you using a surge protector or power conditioner that might be limiting the current/power available to your amp? if so, your amp could be clipping if you've got EVERYTHING plugged into this because it isn't getting enough juice thereby causing the speakers to blow. have you tried plugging the amp straight into the wall and seeing if they still blow?

the reason why i mention this is because i've seen this happen first hand at the good mr. casler's place where he had his amp plugged into a monster unit and it was limiting the power to the amp so when the cannon blasts occurred, the amp (Cinenova amp) clipped and fried the pots...any speaker will fry if underpowered or the amp/receiver is starved for power...even the mighty VMPS RM40s..

Tyson · « **Reply #12 on:** 18 Nov 2003, 08:48 am »

I've never blown a speaker, but I did catch Pez on his knees in front of the RM40's once.

Bill@LakeGeorge · « **Reply #13 on:** 18 Nov 2003, 02:02 pm »

Mad Dog,
Good points. I was about 12' away with the meter. Tonight I will check power going to the amp. I do have everything plugged into a modified BPT. I do not believe that the amp clipped, I would have heard it. Remember this has happened 4 times always with a DVD concert.

Is it possible that on DVD the dynamic range is greater and the bass spikes higher than 95db?