Help with a cutsheet for a subwoofer

**Dennis H** · 05 February 2009, 16:48 Thursday

What do you want to use the sub for? 38Hz is a very high cutoff for a home sub. It sounds more suitable for PA use where you don't really need to play very low. Do you already have the drivers? Again, the 44Hz Fs of the driver is very high for home use.

**HareBrained** · 05 February 2009, 16:59 Thursday

I modeled the driver in Unibox and it's not pretty in that box. It has a 5db rise at the Fb (30Hz, which was derived from playing with the data to replicate the port). Cone excursion really isn't a problem, but the HP@30Hz was obviously used to tame this peak.

You could do a 30L @ 30Hz (4"x30" port, I'd go with a slot port as it'd be easier to fit) for an F3~26Hz and SPL@300W of ~108db. Or you could do 30L @ 35Hz (4x22 port) for an F3~30Hz and SPL of ~110db. Both of these alignments will sound much better then the original box, unless you listen to only rap and enjoy one-note thumping.

These boxes assume you'll be using the active LP @ ~80Hz.

As for the recommended box, the V(total) accounts for driver and port displacements plus the volume. It probably doesn't account for the plate amp displacement, assuming they're going in the boxes. You'll need to get that from the manufacturer and add that to 2.325cf. You also need to calculate the volume of the bracing to be used and add that too, before you'll now how big the pieces you'll need.

I would strongly recommend either thicker MDF, doubling up on the 0.5" ply, or laminating the ply over 0.75" MDF. You will need substantial bracing inside the enclosure with only 0.5" ply.

**Dennis H** · 05 February 2009, 17:16 Thursday

I checked those drivers at PE and they are $130 each. IF you're looking for a home sub and IF you don't have the drivers yet, you can do much better for the money. If you already have the drivers we can try to help you make the best of them.

**stangbat** · 05 February 2009, 18:24 Thursday

I have nothing to add regarding the design but there is a free application to generate a cutsheet available here:

Cut List

http://www.delphiforfun.org/programs/cutlist.htm

It is kind of clunky, but it does work. I've used it for several projects.

**Nateadwg63** · 05 February 2009, 19:19 Thursday

No, don't have the drivers yet. I looked at those because I have used Eminence drivers before for a PA speaker build. I am certainly open to other suggestions, esp if they have detailed plans posted already.

I want to use them for strictly HT use, watch ALOT of blu-ray and DVDs and also subscribe to every movie channel avail on my cable system - not really into 2-channel as much now... have a teenager and bad arthritis, so we just watch alot of movies.

I would like to do a pair because I am planning on building a 7.1 system using the single driver design over at zaphaudio, and John recommends dual 8" or 10" subs with his design. This is what he says about suitable subs.

"There are a few setup details to really help this system integrate with a single or dual sub. First, if using a HT receiver, set the crossover to 150 hz if you can. Then, set your sub's plate amp crossover to 150hz too. As a result you get the natural 2nd order driver rolloff with the plate amp 2nd order rolloff to assist the HT receiver rolloff (usually 4th order but sometimes only 2nd) to an effective tall order slope, usually around 6th order.

With mains this small and the high crossover points they require, two separate left and right subs are the best route. Dual subs don't need to be stereo, mono is fine. You could have one 8 ohm sub with a plate amp, and another outboard 8 ohm sub wired in parallel with it for use on the other side. This arrangement will offer excellent integration at high crossover points."

Just want something that is not too complicated to build, thats why I thought of a ported design. Any suggestions are welcome... I am open to using a external active xover and pro amp instead of plate amps also. If I can build the 7.2 system fairly cheap, I can justify those components.

Nate

**Dennis H** · 05 February 2009, 19:35 Thursday

Okay, considering you want to cross at 150, I'd recommend the Dayton reference series subs, either the 12" or the 15". Many subs have a problem playing as high as 150 but the Daytons are great up there. A pair of the 15" in small sealed boxes will play much lower and much louder than the 10" you were considering. They will easily play down into the low 20s. The boxes won't be too much bigger than what you were considering, will be even easier to build than ported and the drivers don't cost too much more. Sealed boxes also don't need a highpass filter to protect them from low frequencies.

Page not found

http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=295-464

Page not found

http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=295-468

Edit: you can save some money on amps if you buy a single Behringer EP2500 instead of a pair of plate amps.

Page not found

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-747

**Nateadwg63** · 05 February 2009, 21:14 Thursday

Thanks... I will put the 15's and the amp on my to do list... I will search a few forums and see if I can find a set of sealed plans w/bracing etc already in use.

Nate

**HareBrained** · 06 February 2009, 00:00 Friday

The 10" RSS265HF is on sale for $105. A pair would do nicely in all but the largest of rooms.

You may want to rethink the 150Hz as voices have a fundamental harmonic as low as 85Hz. Just a thought.

Help with a cutsheet for a subwoofer

Help with a cutsheet for a subwoofer

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment