DIY sealed sub

[Spligsey]

Hello chaps
I've been keeping an eye on this section for a while now & have been interested & energised in attempting to make my own DIY sealed sub.
Most of the subs i have owned have been sealed & they seem to give the best results for music & films.
I used to own a Velodyne HGS-18 years ago before the sprogs started to perform open wallet surgery on me
I was looking at something like (inches) a 25 (H) x 25 (W) x 25 (D) as this fits nicely into one of the only gaps i can fit a subwoofer in
I would use 25mm MDF.
I'm not after the ultimate depth/abusing foundations etc - just a nice mix of low down grunt & a bit of upper bass punch

So, couple of questions (warning - total noob)

1 What size driver would be best for that box side - 15" or 18"?
2 I have a pro stereo power amp upstairs - which is 250w per channel @ 4 Ohms - 150w into 8 Ohms - would i need a slightly beefier amp like a Behringer?
3 Bracing - is it good form to have 2 x Braces - or will 1 do?
4 Bracing - sorry for the stupid question, i see that the bracing has circular/square/rectangle cut-outs, are the cut-outs to add stability - yet still allow the box size to be reasonably big?
5 Is there a special sealant that needs to be used for MDF?

Thanks very much for your help

 

[Johnny.G]

Others of greater knowledge will be along shortly Spligsey, but that sounds like a box size with potential , but they will need to know the current status of the wallet i,m afraid, have you a budget in mind for the project.

 

[Spligsey]

Others of greater knowledge will be along shortly Spligsey, but that sounds like a box size with potential , but they will need to know the current status of the wallet i,m afraid, have you a budget in mind for the project.

Hello mate, cheers for the reply
I suppose i have to factor in a possible purchase of a "beefier" amp, if my current one will not do the business in driving a 15-18"
I suppose i was looking at around the £600 mark or so (+ possible new amp)
Be nice to get some kind of bass back as i have been subless for a few years now - last sub i owned was a Mackie HRS-120 (pro sub)

 

[homeboydeluxe]

An Fi SSD 15" or 18" subwoofer with a Behringer EP2000 would be a very nice option!

Others here have used Fi drivers with great results.

For a cheaper build, two JBL GTO 15" drivers in 6-7 cubic feet, in a dual opposed config, would equal the Fi 18"( in a similar size box, with 1000 watts or so) for less money.

 

[steve deakin]

I made a 24x24x36 cabinet out of 25 mm MDF. B&Q cut up a £30 8x4 board free of charge and are accurate to about 1 mm. If you want a smooth finish, make sure you prime (ordinary primer undercoat) the screw holes prior to the screws and filler going in otherwise the filler seems to bulge in the holes. For bracing I cut a 18" by 18" square out of a single 22" x 22" x 25 mm board, positioned midway in the cabinet it proved effective. I used PVA wood glue, followed by 3 coats of ordinary primer undercoat on the exterior.

 

[Spligsey]

An Fi SSD 15" or 18" subwoofer with a Behringer EP2000 would be a very nice option!

Others here have used Fi drivers with great results.

For a cheaper build, two JBL GTO 15" drivers in 6-7 cubic feet, in a dual opposed config, would equal the Fi 18"( in a similar size box, with 1000 watts or so) for less money.

Thanks very much mate - i shall take a look at those suggestions.

I made a 24x24x36 cabinet out of 25 mm MDF. B&Q cut up a £30 8x4 board free of charge and are accurate to about 1 mm. If you want a smooth finish, make sure you prime (ordinary primer undercoat) the screw holes prior to the screws and filler going in otherwise the filler seems to bulge in the holes. For bracing I cut a 18" by 18" square out of a single 22" x 22" x 25 mm board, positioned midway in the cabinet it proved effective. I used PVA wood glue, followed by 3 coats of ordinary primer undercoat on the exterior.

Thanks very much mate - i have a B&Q Warehouse just down the road from me, so will get them to do the cutting.
Cheers for the tips too.

 

[Member 639844]

An Fi SSD 15" or 18" subwoofer with a Behringer EP2000 would be a very nice option!

Others here have used Fi drivers with great results.

For a cheaper build, two JBL GTO 15" drivers in 6-7 cubic feet, in a dual opposed config, would equal the Fi 18"( in a similar size box, with 1000 watts or so) for less money.

If only it was so simple. It might be equal in terms of output, but the drivers are very different.

 

[homeboydeluxe]

Absolutely, the Fi driver are much better subs, but will he get a SSD or Q series 15" or 18" sub and still have money for a good amp, MDF and paint etc?

Would be tight for 600 pounds, Is there UK based Fi dealer?

 

[Member 639844]

A Q series driver will set you back about 350 for an 18, the SSD's are about 100 quid cheaper. Fi do have a UK dealer, and thats the main reason I recommend them over the other high end direct from USA only drivers.

There is nothing wrong with a pair of the GTO's though, and at £100 each they are excellent VFM for sure. Its just I wouldnt quite say a pair of the JBL15's are a match for the single Fi18.

 

[Spligsey]

Thanks very much chaps - appreciate all your responses.
Trawling through a few threads, is it bladeice that i can get the Fi drivers from (in the UK)

Cheers

 

[Member 639844]

Yeah thats the one. Just to clarify, I wasnt saying dont use the JBL's they are known for being a very decent driver and very hard to beat for the money. FWIW though, a single FiQ18 will still work in a much smaller cabinet than a pair of JBL's.

 

[steve deakin]

If your interested, the JBL GTO 15" are available for £80 delivered from Amazon at the moment.

 

[Spligsey]

Cheers lads, thanks for your help & recommendations.
Much appreciated