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It works fine when I pump less than 300 watts in it (which is enough to get some things in the house buzzing). Anything more and it makes a metallic rattle or clicking like sound when there are quick bursts of heavy bass. I checked the dustcap, and it seems like it's on tight, no other noticible issues. I originally had an oaudio 500watt plate amp that powered it. I bought the amp thinking that I was never going to dump too much power into the sub, but after talking to John at AE, I figured there was a possibility of amp clipping. The problem was that I'd get rattling with the gain up only about 25 percent. I borrowed a friends sub and ran it off the oaudio amp at nearly full gain with no clipping.

I thought perhaps that the AE speakers were just a bit more power hungry, so I got the Behringer ep4000 amp, wired it up in mono, thinking that I wouldn't have any clipping problems. Rattling/clicking still appeared.

Now I did try running it in a vented enclosure, just to see what would happen. I basically removed the plate amp and put in a temporary piece of wood to cover the hole, and added an external vent to it tuned to 20hz (the box was 4 cubic feet). I had the same metallic clicking sound during moments of heavy bass with modest volume levels. (It did have slightly more sound ouput though).

So I'm more than a little dissaspointed in this driver (especially after waiting so long to get it), and I think I'm just going to cut my losses on it and the o-audio amp i had gotten for it, and just try again. I don't want to pay more for passive radiators to try to salavage this driver.
sounds like an unraveling coil or spur on the coil. has the sub been bottomed out? (loud whack from former slamming on bottom plate) or does this sub soft bottom.

Take the speaker out of the enclosure and run it free air. can you reach Xmax without the metallic sound free air?

This looks great. I noticed on the DIYcable website that they say the Tempest would work well setup as: "180L (6.35 cubic feet) Ported and tuned to 19Hz with 15% poly-fill." So this is right in line with my limitations. Do you think that my amp could power two of these subs, or would I need one amp per sub?
I read on here that there is no point to stuffing a vented enclosure

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I also took Blaser's advice, which was great - discuss the enclosure size with my wife. I showed her winisd, explained what the lines meant. I showed her what -3db sounded like on our 8 inch sub, and let her play with the box sizes in winisd to compare the results. It wasn't long before she was taking the tape measure and playing with the dimensions in our TV room. After seeing the compromises to be made in winisd, she thought that 8 cubic feet would produce a good effect while still being workable space-wise.
youre my hero

Because of that, I want to be able to put in a movie, feel the explosions a bit, and not have to worry about coils getting too hot, or drivers bottoming out. That's why I'm thinking running two at modest levels would be better than running one to the max. I've always been the sort to double up on hardware, rather than run what I got to its limits.

Doubling up on it would be the extra impact I want, without the extra worry about exceeding the limits of the equipment. Like I said before, I don't want some intense explosion in the movie at some critical plot point disrupted by my amps clipping or my subs making funny noises.
well said!


So I had a chance to run some sine waves through it with the ep4000... but this time, I sealed up the hole in the back of the enclosure that the Oaduio plate amp was in. I also ran it unbridged. Both were a stupid oversight on my part. Wow, what a difference.

First of all, I had to double check the software I was using because the sine wave sounded completely different than what I was hearing previously. It had a much more distinct oscillating quality to it, if that makes sense. I'm not saying it was cleaner or better, just different.

After slowly creaping the levels upward, I eventually maxed out all of the gain knobs. The woofer was clean and handled it all fine. I then gradually lowered the fequency from 200hz down to 16hz, watching the excursion carefully. It had no problem with any of it. Even at 16hz, it didn't bottom. I was not running any type of high or low pass filters.

Needless to say I am pleased with this development, and owe it all to the encouragement I got from you guys to give the driver a second chance. After all of this, it looks like the driver had more of an appetite than the Oaudio 500watt amp could reliably deliver. Thanks to the build quality of the AE driver, and the soft bottoming feature (and me leaping out of my chair to unplug everything the moment I heard a "clink") it looks like the driver is undamaged.

If all of you don't mind providing additional guidance, I could really use some direction designing the 7 to 8 foot enclosure. I'm thinking slot port, but have no experience with that type of port. I'll do some more research on this point before I solicit any specific advice from you guys.

Thanks again.
great news!

I'm going to have to remake the enclosure anyway. I had built a 4 cu. ft. cube, which it turns out, fits very poorly into our room. I really need something less deep and taller. Oh, and the 1.25 inch thick walls were overkill, so it is ridiculously heavy.

Because I thought that I'd also us it for music, I chose to go sealed. I completely underestimated the abilities of my towers though, and can now dedicate the sub(s) to home theater exclusively. As such, I'd like the response flatter toward 20hz. I don't care about anything lower than that, so that should keep the box size in check.
why not tune lower?
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