# Questions about a powered HT sub



## grampi (Jun 29, 2007)

I currently have an enclosure which I built myself. It has a 15" Tempest sub and a 250 watt plate amp in a sealed enclosure of a volume that's considered reference for this driver. I'm not happy with the sound of it. It seems to have plenty of output, but it has no definition and the bass is very boomy sounding. I've played around with the phase and crossover controls on the amp, but it didn't help. I like tight, punchy bass. I'm wondering if I should just build, or even buy a prefab enclosure (from a place like Parts Express or something), a new driver, and another amp. I'm sure the Tempest is cabable of producing the type of bass I like, it's probably just a matter of putting it in the right enclosure, but would one of their powered sub kits (like the ones that come with the Titanic subs) would be more suited for what I'm looking for?


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## niceguy (Mar 12, 2006)

I don't know much about the Tempests in HT (though I sat in an old CSO member's GMC Sonomo blowthrough with 4 Tempests) though I don't think they were too different from the Tempests....

Nothing else to add that you haven't mentioned but xover below 80hz, make sure the enclosure is air tight and well braced,etc...could be it's physical location (room nodes,etc)...

Don't know what else to say


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## 60ndown (Feb 8, 2007)

grampi said:


> I currently have an enclosure which I built myself. It has a 15" Tempest sub and a 250 watt plate amp in a sealed enclosure of a volume that's considered reference for this driver. I'm not happy with the sound of it. It seems to have plenty of output, but it has no definition and the bass is very boomy sounding. I've played around with the phase and crossover controls on the amp, but it didn't help. I like tight, punchy bass. I'm wondering if I should just build, or even buy a prefab enclosure (from a place like Parts Express or something), a new driver, and another amp. I'm sure the Tempest is cabable of producing the type of bass I like, it's probably just a matter of putting it in the right enclosure, but would one of their powered sub kits (like the ones that come with the Titanic subs) would be more suited for what I'm looking for?


try it in different locations in the room, where it is in the room will make a huge difference to how it sounds at the listening chair. once you have found the best location for it, you can add lengths of scrap wood (2x4) to make the internal volume smaller, this generally makes a sub sound tighter.

http://www.kettering.edu/~drussell/Demos/RoomModes/driving.html


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## grampi (Jun 29, 2007)

I don't know what the problem could be. I made sure the enclosure was well sealed and well braced. It's also corner loaded in the living room which is supposed to be the best location. I believe the crossover is set at or below 80hz, but I know it's not set too low as that too would cause it to sound mono-tone-ish. I'm sure the amp is powerful enough, and I've heard raves from other people who have this sub and they just love it, so I don't think the problem is with the equipment, it must be the enclosure. I'm trying to find the specs for this sub so maybe I can try a different enclosure, but I'm not having any luck so far.


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## MIAaron (May 10, 2005)

If you can, throw it in the adire aligement ported enclosure. You just gotta try it sometime, it's worth the effort. 

Let me know if you need the adire documentation on the tempest.


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## Robert_J (Nov 9, 2006)

If you want the specs, they are available on Adire's old site. You can also try archive.org to find the PDFs that contain the different alignments. There were 3 sealed alignments for the Tempest, which did you choose? You can tell from the enclosure volume.

It may not be the enclosure itself. It may be the alignment. It can also be the room. Corner loading is not always the best place for a sub. Have you plotted the frequency response of your sub? All it takes is a Radio Shack SPL meter and some test tones. I can link you to a spreadsheet with the correction values. Once that is done, you can actually see the frequencies that cause the booming sounds. Adding a parametric EQ can easily eliminate that problem without building a new enclosure.

-Robert


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## grampi (Jun 29, 2007)

Robert_J said:


> If you want the specs, they are available on Adire's old site. You can also try archive.org to find the PDFs that contain the different alignments. There were 3 sealed alignments for the Tempest, which did you choose? You can tell from the enclosure volume.
> 
> It may not be the enclosure itself. It may be the alignment. It can also be the room. Corner loading is not always the best place for a sub. Have you plotted the frequency response of your sub? All it takes is a Radio Shack SPL meter and some test tones. I can link you to a spreadsheet with the correction values. Once that is done, you can actually see the frequencies that cause the booming sounds. Adding a parametric EQ can easily eliminate that problem without building a new enclosure.
> 
> -Robert


Yes, I believe there were 3 sealed alignments and I chose the middle sized one, which I believe was the reference model. I don't know how to plot the freq response. How do you do that? To what would I add the para EQ, my entire system, or just the sub? Are the Radio Shack SPL meters expensive?


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## Robert_J (Nov 9, 2006)

A Shack SPL meter is about $45 if you can find one. You would create a CD with test tones. And there is free software that will create the .wav files with the correct cones. I created a CD with tones matching the frequencies on the PEQ spreadsheet. With the SPL meter sitting on a tripod in my seat (the meter is at ear level, pointing at a 45 degree angle up), I play each tone and write down the reading on the SPL meter. I transfer my values from a notebook to the spreadsheet. It will graph the room's response. The controls at the bottom simulate a Behringer Feedback Destroyer. If you want to use the PEQ on the Dayton amps, then only use 1 filter in the spreadsheet. If you want to use an ED EQ.2, then use 2 filters in the spreadsheet. 

The simulated response is VERY accurate. I used this spreadsheet with my Behringer EP-2500 amp/BFD/TC Sounds TC-3000 15" subs. I used 6 filters to flatten the response and after I re-measured, it was within 1db of the simulation. It took about 2 hours total to measure, simulate, enter data into the BFD and re-measure. I plan on adding additional curves into the BFD memory for music (a little boost in the 50hz range) and demo (crushing low end for demoing action movies).

-Robert


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## MrH (May 27, 2006)

Like said before, dont rule out the alignment. I also built a sealed 15 ht sub with plenty of power. Could never get a nice balance in the location I wanted it placed. Put a ported 8" infinity in the same spot and it sounded much more balanced and natural than the sealed 15. Now I'm going to have to put the damn thing together and mess with it.


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## sqshoestring (Jun 19, 2007)

I agree, if it does not sound right you likely have a peak in the response. You will have to identify it and then EQ it out if you can't by location or enclosure changes. Did you play with stuffing the box or not?

If you get a chance to play with a parametric, you can simulate that sort of by moving the boost around. I have done that with a narrow band and can hear it sound bad just like I have heard other subs/speakers.


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