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My first 18" ported box build

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Glenn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Glenn Quote  Post ReplyReply Direct Link To This Post Posted: 06 May 2009 at 12:54pm
MarjanM,
You say he may have tuned the box too low and there is a lot of excursion above this frequency. Couldn't he also have tuned too high (like 60hz) and the sub bass is causing the excess excursion.
 
Lastly without looking at the eminence specs - maybe this drivers also has a short xmax.
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aperrado View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aperrado Quote  Post ReplyReply Direct Link To This Post Posted: 07 May 2009 at 12:03am
that is the point I dont know the t/s parameters  are bcs this is a eminence oem speaker eminence dont want to give info on oem speakers and the company that made a cabinet dont tell me the specs too. the speaker in the company that made the cabinet  sell this speaker for 350.00 UD.
Im hard to learn but still asking
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MarjanM View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MarjanM Quote  Post ReplyReply Direct Link To This Post Posted: 07 May 2009 at 3:44pm
That is why he has to have a dsp and try a few different HP filter frequencies and be sure what is wrong.
If it is tuned too low cutting the very low frequencies will cure the thing.
Can you check where that box is tuned? That will show you the problem also.
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713
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Glenn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Glenn Quote  Post ReplyReply Direct Link To This Post Posted: 09 May 2009 at 5:06am
You can get a rough idea by playing a test tones through them at various frequencies and feeling the excursion. I do this with winisd signal generator if nothing else aroung. Don't really have high end gear to test so I use my ears and what ever I can think of.

You would expect an 18" to be tuned around 40hz, so for a given power input expect a reduction in cone movement here compared to 30hz and 50hz.

In the case of the cab referred to in this post, I would sweep from say 75 hz down to 25hz in 5hz increments. Try to find a frequency where cone movement is least compared to the frequency above and below 
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Glenn View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Glenn Quote  Post ReplyReply Direct Link To This Post Posted: 09 May 2009 at 5:09am
Turn off any HP or LP filters.
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aperrado View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aperrado Quote  Post ReplyReply Direct Link To This Post Posted: 09 May 2009 at 5:53am
ok I will try it  ty
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Post Options Post Options   Thanks (0) Thanks(0)   Quote edjay Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2009 at 11:29pm
Sorry, I've got no info to contribute but I'd like to see what happens.  :)
Every little helps
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aperrado View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aperrado Quote  Post ReplyReply Direct Link To This Post Posted: 16 May 2009 at 4:02am
lol  np it is open  forum we can search here and there  and maybe we can learn what we  need .
Im hard to learn but still asking
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Post Options Post Options   Thanks (0) Thanks(0)   Quote edjay Quote  Post ReplyReply Direct Link To This Post Posted: 16 May 2009 at 8:36am
Thumbs Up
Every little helps
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chowlu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote chowlu Quote  Post ReplyReply Direct Link To This Post Posted: 19 July 2009 at 4:03am
did you solve the problem yet?i would like to know how it turned outErmm
"adapt or die"
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aperrado View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aperrado Quote  Post ReplyReply Direct Link To This Post Posted: 21 July 2009 at 4:29am
ok sorry for no answer back I got out the crossover and installed a peavey kosmos  now I dont need to much volume to get good seismic bass it sound very good  the kosmos has a  dial button for subwoofers and for the tops  use kosmos effects
Im hard to learn but still asking
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aperrado View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote aperrado Quote  Post ReplyReply Direct Link To This Post Posted: 21 July 2009 at 4:32am
[QUOTE=aperrado]ok sorry for no answer back I got out the crossover and installed a peavey kosmos  now I dont need to much volume to get good seismic bass it sound very good  the kosmos has a  dial button for subwoofers and for the tops  use kosmos effects
Now I got the eminence speakers back to original cabinet next time going to buy a pair of peavey lowrider 18 for my b&c boxes when I complete it going to write here what happen.
Im hard to learn but still asking
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