Audio Project Amplifier Speaker Loudspeaker Kit
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My IB sub sounds dead. - Click HERE for Original Thread
jonz
After I upgraded my IB from 2 tempest to 4... all was fine.... then I started playing around with the BFD... it was going good.... then as as yesterday....the subs feel like thier running on 7 cylinders..


Things I have done so far to see what the problem is...

- I bypassed the BFD.... no improvement

- I completely removed BFD... nothing...
- I rechecked speakons on amp and tried regular binding posts hookup.... nothing...( I did this cause I added the speakons recently)

- I checked all settings on my AVR for sub out... nothing...


- I disconnected my main speakers and played only my IB...and it can't hit more than 92 DB on my digital RS meter... the cones are moving a lot... but it's completely void of any visceral feeling....I know definitely something wrong...but can't figure it out...


I checked all connections on subs.....


What else can I do?
Cloth Ears
A mystery - let's call Nancy Drew (actually Sherlock might be better).

My first instinct is bench test it.
First, check each driver individually (and out of their baffles). Might be a bit of work, but once they're all on the bench then testing them is much easier. Only amp and source for this bit.
If they all work individually (and my guess is 'no'), then wiring them up again and retesting (on the bench) is the second step. Only amp and source for this bit too.
Then start bringing in your other elements (you'll have to excuse me but I haven't a clue what a speakon or a BFD is) and checking it with them.
If you still haven't found fault, then I'm stumped - but putting them back in the IB and seeing if there's an improvement might find that there was a wiring problem that you hadn't discovered earlier.

Best of luck!
454Casull
Kicked a hole in the baffle?
jonz
This is a Speakon connector..





this is a BFD...




I tried running them one by one ... they still sound weak...

there's two things left..maybe the amp .. or the HTReceiver sub out signal is weak... if thats possible....?
Cloth Ears
I am enlightenend - I've got other Behringer stuff, but I didn't think I'd need an BFD for my stuff at home.

The coils aren't hot, are they (ie. been driven a bit hard and literally hot)?

What's your wiring like? Tempests have 2 voice-coils a-piece, don't they? So that's 8 in total. How many amps have you got powering them and what's the actual wiring like - in other words, whats the load on you amp (or amps)? By my reckoning you would have 1.75ohms if you running them series/parallel/parallel or 7ohms if you're running them series/series/parallel. Prior to this you were probably running them series/parallel, giving a 3.5ohm load to the amplifier.
jonz
quote:
Originally posted by Cloth Ears

What's your wiring like? Tempests have 2 voice-coils a-piece, don't they? So that's 8 in total. How many amps have you got powering them and what's the actual wiring like - in other words, whats the load on you amp (or amps)? By my reckoning you would have 1.75ohms if you running them series/parallel/parallel or 7ohms if you're running them series/series/parallel. Prior to this you were probably running them series/parallel, giving a 3.5ohm load to the amplifier.



Correct, I was running them before at 4 ohms each driver... at 750 watts per off a Crest pro amp cpx 2600..

Now I am running them at 8 ohms per pair at 500 watts each side.


IB subs do not require massive wattage ...Adire recommends in an IB configuration around 150 watts each.... so my power requirements are ample.
Cloth Ears
What I was thinking of is that, if you'd wired them up incorrectly then your amp might have been overdriven. Probably wouldn't happen with a CPX 2600, as they're stable down to fairly low loads.

Have you tried testing the drivers with a different amplifier, just in case the problem is with the Crest?

Only other thing I can think of is - did it happen recently? Give everything the night off, have 2 aspirin and check again in the morning. Give it a chance to cool down (amp and speakers).

You might have to get the more technical people onto this as I'm about out of ideas... Isn't there an IB site/forum somewhere out there (I'm sure there was a link posted on this forum a couple of years ago)?
sqlkev
-check out the resistance of each speaker to see if they're all okay
-test out one by one with a fullrange signal then sub output signal
-hook up 1 sub make sure it plays as intended, then 2 (make sure polarity is correct), does the pair sound lounder than 1? add 1 more and do the same for the fourth

From what you described, it seems like there's a mishap in wiring somewhere (wiring could come loose or something) and cause the drivers to cancel out each other or the loose in wiring could cause the nominal impedance of the IB subs pretty high.
jonz
I tried playing the subs in pairs they still sound weak... I checked all speaker wiring it's all okay...


I have to check the amp wiring next.. and then swap out my amp for another one .... this is depressing.
Cloth Ears
quote:
Originally posted by jonz
I have to check the amp wiring next.. and then swap out my amp for another one .... this is depressing.

jonz,

"Don't worry, be happy"

Without trying to sound insanely upbeat - think of it as a learning curve (oh, that does sound insanely upbeat). Hopefully you will find something interesting that doesn't cost you any money and you'll be able to impart wisdom too us all. Hopefully.

I say this as I've got a Behringer 2500 ready to drive a subby of my own, and I don't want to end up in "92dB land" :):):).
Bill F.
quote:
I tried running them one by one ... they still sound weak...

If you run them individually, in pairs, or even three at a time, the undriven driver(s) will allow a pressure short circuit, and it's bound to sound very weak, even in the best of health.

When I was setting up my friend's IB, I ran into a similar problem, which I discovered to be one driver wired out of phase. It was connected correctly according to the marked polarity, but the marked polarity was incorrect! It takes a battery test to really figure out polarity. Don't necessarily trust the factory markings.

Another thing to check would be the DCR of each woofer's coil to make sure none are partially burned.
jonz
I check the pairs with a 1.5 volt battery they are all okay..


I checked all coils and they are alll 7 ohms....


There's 2 to each sub... I wired in paralle to 4 ohms then to series in pairs to give me 8 ohms a pair... I don't understand they were fine last week... at medium to high levels.

jonz
Okay guys I feel like a dummy.


After checking the amp connections like 100 times I never realized the ultimate goof I had made....






My subs are back and the RS meter hit 119 db!!!

and my wife is screaming that something fell upstairs ....

Now I am happy as long as stuff keeps falling.....:wave2s:


Thanks to all of you..:cheers:
Cloth Ears
I can't see the picture... what was it, please? I'm always in the market to find out how not to make a goof...

P.S. Congrats on getting it back up!

P.P.S. Now go and be nice to your wife...
jonz
this....
TwisterZ
We have all made simple little mistakes like this so don't beat yourself up to much. My push-pull sub was doing the same thing but I had the 2 speakers on different channels that I usually turned on togeather. One day I turned 1 on and the sound came up then I turned up the other and the sound went away, :xeye: silly me. Now with the polarity right Darla tapping on the fish tank will set you free & make things fall off every shelf in the house. :D

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