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Discussion Starter · #1 ·
I just finished my 4cuft sealed enclosure for the dayton ultimax 15. I'm using the dayton 1000 watt plate amp to power it. The problem im having is a rattle from the driver area when played loud at low hz. Somewhere between 30 and 35 hz. I only occasionally hear it during movies but it is very noticeable when doing a frequency sweep. Could I be just overpowering it or is there something else I can check?
 

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Discussion Starter · #5 ·
I have the gain on the amp half way and the receiver at +2. Audyssey had it at -12. From what I've read on different forums with this size sealed and poly stuffed enclosure I shouldn't have a problem with over excursion.
 

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Pull the driver.

Run a sweep with med power.

Did you hear the same noise?

Repeat with a tiny bit more power till you hear a bad noise.

Was it the same noise?


If you can't get it to repeat the same noise, then it's probably your box (which isn't very likely)

Normally, any noise comes from the driver being pushed too hard.
 

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Could be a loose screw or something in the box or amp that rattles at that resonant frequency. Go with Looney's advice and report back. As Looney said, unlikely. Most likely it's the driver.
 

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Discussion Starter · #9 ·
Ive checked the screws several times and as far as I can tell there is no air leaks. I used titebond 2 wood glue and screws to assemble box. Silicone caulk to seal all seams and 4 lbs poly fill
 

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Discussion Starter · #10 ·
This is the first time ive ever built anything like this and maybe im expecting too much. It gets loud enough to rattle the windows without the driver itself making any noise at all. I just thought with a driver max rating of 1600 watts I couldn't over drive it with 1000
 

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Yank that driver and free air test it. You will know without a doubt what it making the noise when you do. Check over the driver for loose parts while it's out.
 

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Discussion Starter · #13 ·
I downloaded winisd but cant figure out how to use it. Can anyone here run the numbers on my setup and let me know what this sub should be capable of?
 

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You have over excursion with 1000W and 4 cu. ft. The 1600W rating has nothing to do with excursion capability. It is based on the amount of current you could put through the voice coil without melting something. This would be a candidate for a smaller box with eq.
BTW, parts express says 800W rms

 

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Discussion Starter · #15 ·
I did see on parts express the 800 rms but it also says 1600 max. I built this box based off the recommended size on their website. The dayton amp has eq so maybe I could just dial back the receiver setting to -4 or so and add eq down low. Parts express also told me that 4 cuft and 1000 watts would be perfect for this sub
 

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Well, I had a bad rattle in a sub once that wasn't from the woofer or the box. Turned out I was clipping the signal to the amp. My receiver was sending too hot a signal to my equalizer which, in turn, sent too hot a clipped signal to my amp and that's when the bad noises happened. It is possible +2 dB on your sub channel is sending too much voltage to the Dayton amp and causing it to clip. Who knows? The PE guys ought to know a good design for this woofer. I just plugged in the numbers...


BTW, don't add eq! At least not until you've figured things out...
 

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Assuming this plot is correct, and with a driver Fs of ~20Hz your prob exceeding X-max 25-40 Hz. Thats likely the sound your hearing. You dont hear it below ~25Hz likely due to the impedance spike of the driver and signal chain roll off below that.


How does the FR look?


Test the driver free air.


If you find the box is just too big and too much power(over excursion), Options:


Close off some of the box inside to effectively reduce volume.


or


You have EQ on that amp try a -3db cut @ 30Hz with a moderate Q and see of the clanking goes away.


or


Turn it down(I never had good results with this one
)
 

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Discussion Starter · #18 ·
Will I end up with the same output keeping the box size the same and turning volume down as I would if I made the box smaller and adding eq?
 

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According to the simulation I have, 3 cu. ft. looks better. Below is excursion and SPL for 3 cu. ft. and 4 cu. ft. with 1000W, NO eq. The 3 cu. ft. box actually gives a little more SPL for music and only loses out a hair in the low end for movies....


 

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Looks like the 22mm xmax in the plots may also be incorrect. I just downloaded the .wdr file from HTS. PE says xmax is 19mm so there is a possibility you are way over-shooting with 1000W. 2.5 cu. ft. might be a safer bet


 
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