Building an odd cabinet for a 200s??

[mediaslave]

I have a 200S with its original 215 cab, and I am looking to get another 200s to build an odd cabinet for... The design I have in mind is for a two way ported enclosure with one 18" and one 10" speaker.  The surface area of the two combined is nearly the same as 2 15" speakers, so I wanted to try to keep the cabinet around the same size as the 215.  

I run my 200s at nearly max volume now, and it is fuzzy and dirty, but rich as hell sounding, which is great for what I do.  I am not concerned with reproducing every fingernail nuance or with getting perfectly accurate sound reproduction.  Basically I just want to rock, and to do it at as high a volume as possible while still retaining that sweet Sunn tone.

Just wondering if anyone had any input on the design, dimensions,  port size or port tuning.  Also, if anyone has any suggestions as to good books to buy on the subject of building such an enclosure, I am looking to do this "by the book," so to speak.  Any acoustical geniuses out there who would be willing to help with some info?

Thanks,
Todd

[Geoff]

Todd -- interesting idea!

You might want to consult with Parts Express support and message board:

http://pesupport.com/

It's a good place to ask questions like this although it's heavily slanted towards home and car audio.  I have obtained some help there in the past.  You might even find somebody to help you model a design with something like BassBox.

I don't have any experience with putting two different-sized drivers in a box for MI.

One thing to consider is that an 18" has a pretty wide frequency response...many go as high as around 3.5 kHz (and of course down deep) as reported in their specs.  You might be able to get by with just an 18" or an 18" and a horn w/crossover if you want to go higher.  I can't speak to the unique tone or potential issues of sticking a dissimilar drivers together.  You might try a chambered design with each driver in its own compartment each with its own tuning and probably a crossover for the pair.  I wouldn't worry as much about equivalent driver surface area as I would about the driver efficiency.

Also, you'll have to find an 18" that'll "cram" argeeably into the relatively small and elongated shape of the 2x15.  I'm talking acoustically (small Vas) as well as physically.

[Anonymous]

You should enclose the 10" speaker in a section seperate from the 18" speaker. The next problem will be to match output of the 2 very different drivers. My first guess would be to choose a very efficient 18 and a not-so-efficient 10. You could put an L Pad on the 10, but that would "burn off a little of your power, and you're only starting with 60 watts!

Tom

[mediaslave]

Thanks for the tips guys, i knew I could count on the board for some good information.  I think I am definately going for a chambered design... I am going to post the specs of the 18" I want to use below... Let me know if there is anything to avoid or take into consideration about it.

- 400 watts RMS, 800 watts program
- 8 ohm impedance
- 97 dB sensitivity @ 1 watt, one meter
- 30 - 3 kHz response
- 4" voice coil
- Cast Aluminum Frame
- Net Weight: 24.60 lbs. (16.16 Kg)

Fs 35
Qts 0.40
Qms 0.7
Qes 0.43
Vas 11
Eff 2.9
Pe 600
Xmax 0.3
VD 57
Re 5
Le 1.75
SD 191
Dia 15.6
Bl 19.2
Mmx 145
Flux 1.2T

Thanks again for the help... I'll keep you posted on progress...

Todd

[Geoff]

Hi Todd,

I sent you a PM here about this driver.

Geoff