[No MSG]

I've been looking for a sub under $300 and concluded that the most cost effective way to go would be to build it myself. I've even narrowed down the parts to the 15" Dayton Quatro mated to a 240 watt plate amp, all from partsexpress.c0m for close to $200 + shipping, if I build the cabinet myself (something I know close to nothing about). Therein lies the problem.


I would prefer to go sealed because: it would (should?) sound better for music, it would be smaller and easier to build, and I listen at only moderate levels. If it turns out that a ported design is best, then I'll go that route. But I need to know what the tradeoffs are.


I realize that I can get the response down to about 20 Hz at high SPLs in a vented box, but I can't seem to figure out how low and flat and loud the same parts would go in a sealed enclosure. I've posted a few questions at the PE forum on this, but I can't seem to get that question answered (even though a couple of the members there have that exact same build). Essentially, the responses I get simply direct me to websites for speaker building that are way over my head. I get the feeling that the forum members are rolling their eyes as they read my questions.


So, can someone offer some guideance on how big a sealed box to build, if I should go that route. Alternatively, is there some website for noobs where I can plug in the specs of the driver to determine how the size of the box would affect the sound of the sub? (I've already loaded the subwoofer simulator off of the FRD Consortium website, but can't make heads or tails out of it--it's meant for people who actually know what the hell they are doing.)

 

[Volenti]

Parts express have a pdf file that lists recomended sealed and vented enclosures for that subwoofer (partsexpress.c0m/pdf/295-560s.pdf), though I would up the size of the recomended sealed enclosure from 2.5cu ft to 3cu ft.


For your first enclosure I would go sealed, they are far easier to build and are much more tolerant of volume errors than vented.


As a novice builder sealed will give you better results than vented.


enclosure building tips;


make it strong, make it stiff, the only part of the enclosure you want moving is the sub, anything else introduces distortion and costs you spl.


You have no doubt heard about standing waves in enclosures, ignore them for the moment, they're not relavent to sub enclosures except in extreme cases.


Do use a polyester based (pillow stuffing) fill in the enclosure.


Do seal the enclosure properly as well as use a gasket when mouning the driver.

 

[DonoMan]

I recommend an Ascendant Audio sub. They have enclosure plans on their site for each one. Otherwise, try LinearTeam's WinISD Pro. It's free.

 

[billybob_jcv]

WinISD: http://www.linearteam.dk/default.aspx?pageid=winisd

 

[kgveteran]

Do yourself a favor and do as I did.Open your local yellow pages and look for a cabinet maker.You should be able to get a sealed sub built for 100.00-150.00 depending on the finish.


He'll be able to give you choices on size depending on your internal volume.

 

[Jack Keck]

What I did was to have the lumberyard cut my mdf (medium density fiberboard) to the dimensions that I chose for my sub, which also uses a Quatro 15. I got the 500 watt amp cuz it was on sale for 1/3 off. The original plan was to get the amp you got. Mine is ported and is my first ever project. (5.5 ft3 with a 4" alared port) Don't be afraid of putting in too much bracing. Parts Express also has a forum for DIY stuff. Lotsa guys there have built with this amp and driver, so you can get more advice than you can handle. Furthermore, your sub's gonna rock.


If you do not have clamps to hold the pieces together while the glue cures, use strapping tape.


I used Gorilla Glue and recommend it. It fill gaps. I still caulked (Hey, the lumber yard got the cuts closer than I was going to be able to do!)


BTY, I have spent the last 29 years as a civil servant and hold a degree from a major university. Translation I barely know how to do anything, and I was successful. You should have no problem. I got all the advice I needed from forums like this one.


Don't be afraid to ask questions. Better to be embarrassed about what you don't know than to waste the money screwing it up!

 

[No MSG]

Quote:

Originally Posted by Volenti Parts express have a pdf file that lists recomended sealed and vented enclosures for that subwoofer (partsexpress.c0m/pdf/295-560s.pdf), though I would up the size of the recomended sealed enclosure from 2.5cu ft to 3cu ft. For your first enclosure I would go sealed, they are far easier to build and are much more tolerant of volume errors than vented. As a novice builder sealed will give you better results than vented.

Thanks for the tips. I did read the recommended sealed enclosure on the PE website, which gives an F3 of 38 Hz for that 2.5 cu ft design. But it seems like most people have gone with a 3.0 or 3.5 volume instead. What effect would increasing the volume to 3.0 or 3.5 box have on the low end extention and other sound characteristics?


Also, the description on the Quatro states that the F3 number is inflated by the high SPL in the > 100 Hz frequencies, due to the driver's high sensitivity. So, it sounds like if I'm using the sub for only

In the end the most important question is this: would a sealed version of this subwoofer be very good for HT?


Thanks again .

 

[billybob_jcv]

I'm no diy expert, but 240w for a 15" driver in a sealed sub seems low compared to typical commercial subs. I'm wondering if the 12" driver might not be a better match to that amp. If you want more extension, then maybe you could add a port?

 

[No MSG]

Quote:

Originally Posted by billybob_jcv I'm no diy expert, but 240w for a 15" driver in a sealed sub seems low compared to typical commercial subs. I'm wondering if the 12" driver might not be a better match to that amp. If you want more extension, then maybe you could add a port?

From the forums, this is a tried and true combination. The driver has a sensitivity of 92 dB and can handle 300 watts RMS. Several people have said that it outperforms the 12" Titanic kit (as far as siound quality) at half the price.

 

[12andy]

No MSG, try UniBox for your modelling needs. At first, I was overwhelmed with all the variables and whatnot, but after plugging in some numbers (T/S parameters for the driver) and playing around somewhat, things got much easier to understand.

 

[kgveteran]

That is another option, letting the mill cut the wood for you.Which leaves the assembly process.


I also agree that 250watts may give you enough power but you want a bit of headroom.Sealed enclosures require lots of power.To move that driver with that much spring requires power.Shoot for the 500watt amp if is affordable.


Look at Audiogon for used subs.You never know, you may find the sub of your dreams.Or two subs!

 

[No MSG]

Quote:

Originally Posted by kgveteran That is another option, letting the mill cut the wood for you.Which leaves the assembly process. I also agree that 250watts may give you enough power but you want a bit of headroom.Sealed enclosures require lots of power.To move that driver with that much spring requires power.Shoot for the 500watt amp if is affordable. Look at Audiogon for used subs.You never know, you may find the sub of your dreams.Or two subs!

If the Quatro 15" driver is rated to 300 watts RMS, would there be a noticeable benefit to using a 500 watt amp? It seems that almost everyone who gets the Q15, uses the 240 watt plate amp.

 

[rlj5242]

Power ratings on subs are almost useless. That is the power it can handle in an hour (or some other specified time) before the voice coil melts. Depending on the alignment of the enclosure, it will take much less power for the sub to reach its physical limits (xmax).


-Robert