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PostPosted: 20 Jan 2009, 00:25 
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Joined: 02 Jan 2009, 19:19
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Hello all. I have wanted to do a test to see if cutting the dust caps off my fullrange drivers and see if it took away the forwardness. It not only did that it took away some of the highs and now the speakers sound blown?
Why do people do this anyways? I would call the company and ask for their advise. I do :down: not know why the speakers sound blown? Any ideas?
God bless. Cheers jeff


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PostPosted: 20 Jan 2009, 00:43 
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Location: Philadelphia Pa
It's really simple actually.

Removing those dust caps also removed the cushion of air trapped in front of the pole piece that was needed to keep the speaker from "bottoming out" and having the voice coil hit the end of its travel.
The speakers are designed with a certain compliance, taking into account that "seal" that is created in the voice coil. The compression/suction action of the trapped air is part of the overall system, controlling the cone on heavy bass notes.


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PostPosted: 20 Jan 2009, 07:55 
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Mag might be right. It make some sense. I would also point out that when people do that they usually put phase plugs in place. These fit near perfectly in the new hole, so escaping air happens very slowly and still provides resistance. Which speakers did you modify? We might find some plugs from Planet10.
Ri

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PostPosted: 20 Jan 2009, 15:17 
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Well it was a pair given to me as a gift to play around with. It is a cambride 3 inch fullrange drivers for the computer. I was very careful in cutting the dust caps off. I did not cut into the main cone or wires looks pretty good for my 1st and 2nd try. Also if you do this to a driver it alternates the way the drivers was made right? Does this happen to the other fullrange drivers like, fostex,b200 abrown sound? I do not know were it went wrong? I did put a socket in the middle as a phase plug still sounded bottomed out and blown? Jeff :?:


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PostPosted: 20 Jan 2009, 17:23 
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I frankly dont know anything about it except that people do that and pop in plugs. Never done it myself, so I am at a loss any further on this one.
Ri

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PostPosted: 20 Jan 2009, 19:55 
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Hi Jeff,
Everyone has their own opinion on this, but on a driver with a sealed dust cap I don't see any reason to install a phase plug unless the dust cap has been damaged. Once you remove the dust cap, the driver is relieved of that pressure and I would expect more distortion and less power handling.

As you noted it really does a number on the high end, which can be good thing with some drivers. But it also makes the already poor off axis response even worse.

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PostPosted: 21 Jan 2009, 00:05 
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Yes I agree. If a driver like a fostex has a sealed dust cap why take it off.
Yes this all makes alot of sense now. If it is a sealed dust cap leave it alone. If it has a hole in the middle of the dust cap you might beable to
get buy with a phase plug. It is sinklng in and makes me feel not so out there. Thanks and god bless. Jeff


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PostPosted: 21 Jan 2009, 07:43 
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Well, now you have a great speaker to test all your new amps on :)
My daughter helped me get a similar speaker for testing when she pushed in the dustcap on my woofer. Very helpful little girl.
Ri

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PostPosted: 22 Jan 2009, 00:07 
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Hows that? I have a great little speaker to try out amps on? The 3 inch drivers are blown. They are no go. I was not trying to be rude. Sorry if it sounded like it. I was just letting you know. :up: I have learned alot from this cutting and playing around will the dust caps. Also how do they get the air inside the dust caps? Just a simple question? Cheers and god bless jeff


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PostPosted: 22 Jan 2009, 09:18 
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Nothing better than a junk speaker to try out a new amp on when you are unsure whether the thing is going to destroy your speakers or not. Well, nothing better except a block of resistors, but I like to hear if the music is getting through. Whether it sounds good or not does not matter, its just a test.
Ri

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