jeffp
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Posts: 41
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Post by jeffp on Dec 11, 2006 9:08:21 GMT -7
I've been pushing my IB pretty hard for a few people who wanted to see what it was all about.
I've noticed recently that from one of the subs or channels when I'm pushing the IB hard I get a random squeal or vruuuuup sound if you will. If difficult to describe the sound in text but it's defiantly not desirable.
Does that mean I've damaged one of these RLP-15's? I really didn't think I was pushing them that hard as I have 4 of them being pushed by a 1500w amp at half gain.
Any ideas on how to locate which one it is or what it might be?
Thanks,
Jeff
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Post by Darren on Dec 11, 2006 9:19:35 GMT -7
Hard to imagine you could do any damage to those drivers with 1,500 watts... I have a similar setup and there is no way I could overpower them with only 1,500 watts. Are you sure you didn't run the amp to clipping causing damage to the drivers?
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Post by ThomasW on Dec 11, 2006 9:52:40 GMT -7
As a mechanical system a speaker is relatively simple. And about the only thing that goes wrong with them is the VC rubbing or hitting the back plate. This means it would be odd for a speaker itself to generate a squeal.
Pushing gently the cone inward from the edges of the dust caps you can hear a VC rubbing. If it's only rubbing at high SPL the music will distort (sound fuzzy) like a radio station mistuned.
I have no idea what a "vruuuuup " sound is....
To diagnose this you need to give us all the details of the system starting with the receiver, it's settings, Are you using EQ? It's settings? How the amp is wired, bridged? or 2 channel? And the SPL when this noise occurs.
BTW, the gain setting really isn't a 'gain' setting, it's simply controlling the input line voltage to the amp.
Are you seeing clip indicators when these noises occur? Are the noises occurring on only certain passages or movie scenes, or anytime at high SPL?
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jeffp
New Member
Posts: 41
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Post by jeffp on Dec 12, 2006 9:26:05 GMT -7
Darren: I have the low filter (i think it was called) turned off on the amp. So it "shouldn't" be clipping if infact it really works.
Thomas: For specs it's a Outlaw 990 receiver, everything is set neutral in it. ie: no increase in treble or bass.
The EQ is the Ber. FBD. I have some boost in certain area's for it. I think +6 is the highest I have on one setting. The rest are +1 or negative in some cases.
The amp is two-channel with two speakers being driven by each channel. The SPL # I can't provide as I don't have a meter but it does have to be intensive in sound level to produce the problem, at lower volume everything sounds "normal".
The clip indicator lights does show up quite frequently but as I mentioned above I turned off the filter, so figured it still activated the dummy lights. The sub amp is a QSC RMX 1450.
The sound does only seem to occur at certain scenes where the subs /amp are being pushed to generate a lot of bass. Under lighter loads and/or volume level the problem is not noticed.
From what I'm reading it doesn't sound like a speaker problem but rather a amp issue? I am saying it's only one-channel but I could be wrong as the sound it emites is short in nature but certainly enough to scare you and make you say what the hell was that.
If I get some time at home without the rest of the family there I'll try to produce the noise while recording the sound and see if it's something you could here through the recording, that might be the best way to identify the noise.
Jeff
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Post by Darren on Dec 12, 2006 9:46:00 GMT -7
If the clip indicator lights up the amp is clipping.
+6 on the BFD is a big no-no...that will cause the clipping you are seeing.
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Post by ThomasW on Dec 12, 2006 9:46:33 GMT -7
If the VC's aren't rubbing when you cycle the cones in/out then it's likely the amp is being driven into hard clipping and that's what you're hearing.
If this is the case you need to turn the clip limiters on and keep them on. Hard clipping an amp can cause it to dump DC into the speakers. If that happens you'll have 4 of the largest and most heavy paper weights you've ever seen.....
BTW how did you setup and EQ the system without some form of measurement equipment?
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Post by chrisbee on Dec 12, 2006 16:16:14 GMT -7
Could it be something rattling in the IB construction or in the room or rear enclosure rather than the drivers themselves?
I discovered my other wall rattled on the other side of the double doors only this weekend. I had never noticed it before despite months of critical listening to music and watching many dozens of films at high levels. It was a pink noise test which finally triggered the racket.
REW sets off my doors with a short but vicious rattle on every sweep above a certain SPL but nothing at all below that point.
My old Philips CRT plastic TV cabinet used to rattle like the devil. I never noticed it on programme material but it was very noticeable on sinewave testing.
When you push the limits it is bound to find things to vibrate that you never notice at normal levels. Hopefully your drivers are fine.
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Post by ThomasW on Dec 12, 2006 16:47:10 GMT -7
Darren: I have the low filter (i think it was called) turned off on the amp. So it "shouldn't" be clipping if infact it really works. No having the low pass engaged doesn't prevent any amp from clipping if it's turned up loud enough. There's is a clip limiter, perhaps that's what you're referring to? |
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