D130 BR cab advice

[asilker]

I've seen a few other threads about JBL 15" woofer enclosures, but a lot of them are oriented toward guitar or huge enclosures.

I've got a pair of D130's, planning on pairing them with econo waveguides. Space is a premium in my apartment, and my wife has already expressed that the JBL woofers look suspiciously loud, so I'm trying to build a smart WAF enclosure. Id like to go ported BR.

The JBL c36 design looks like the way to go, but before I start, should I be aware of anything easier/simpler/prettier or of any red flags with the c36?

A continued thank you to all the members who have answere a hundred questions for me this month. You're pulling me into the diy obsession faster than I'd like to admit

 

[weltersys]

IThe JBL c36 design looks like the way to go, but before I start, should I be aware of anything easier/simpler/prettier or of any red flags with the c36?

The c36 looks a bit short to fit a horn in, but if you are satisfied with it's general size and tuning (which looks to be pretty high), you could make it taller and thinner (depth) and fit the horn, and move the port to the bottom. Ideally you want the center of the HF horn to be at your seated ear height.

The 1950's and '60s "Hi Fi" cabinets for the D130 were around 12 cubic feet and tuned low to make plenty of bass with a few watts from what would be considered by Thiele-Small standards a "midrange" driver.

Red flags: The deep recess and hard edge corners will cause diffraction. Of course, when using a musical instrument speaker for home stereo, that may be the least concern 😉.

Art

 

[asilker]

I intend to rest the horn on top of the enclosure for the simplicity of less cuts and more flexibility. Do you not think the d130 is a good choice for home stereo?

And 12ft3 seems an easy enough parameter. I know this is a basic question, but how do you tune a cab lower?

Sorry I've got a very deficient understanding of speaker parameters and what woofers need to accentuate response. Trying to learn a bit more

 

[weltersys]

1)I intend to rest the horn on top of the enclosure for the simplicity of less cuts and more flexibility.
2)Do you not think the d130 is a good choice for home stereo?
3)And 12ft3 seems an easy enough parameter. I know this is a basic question, but how do you tune a cab lower?

1) Horns sound better when mounted on a baffle, and the closer to the woofer the better.
2) It has a rather "pingy" sound in the upper end, but if crossed in the 800 Hz range it's not bad. It has very little excursion, so getting low bass from it requires a big box.
3) Fb (frequency of box tuning) is a relationship between box size and port area and depth. Longer ports tune lower for a given cabinet size.

 

[asilker]

Ok, interesting. As I'm researching, in finding some Japanese rebuilds of classic JBL stuff with d130's and c36 cabs. I'd really like to push forward and give it a try.

That being said, I understand how broad and often asked my next question is, but...
How can I keep a relatively small, c36 style enclosure, and with that parameter coax the best bass response? Is reaching down to 45Hz really dreaming?

 

[asilker]

Ok, so after a few more hours of thinking and talking with le wife about what she's ok having in the living room, I've decided that I want to make an enclosure similar to the JBL C36 cabinet. If I can, I'd like to keep each side of the enclosure below 24", with one port. 15" driver will be mounted at close as is reasonable to the top, and then my econowave guide will be given its own baffle and attached to the top of the woofer cab.

So if anyone would like to jump into this project with me, I need help figuring out specific measurements and what size/shape my port should be. I have a few enclosure emulation programs but I'm still learning how to use them so I don't trust any of my findings. Within the parameters of less than 24" per side with 1 port, how can I tune a cab for D130 15" drivers?

I can post Theile parameters if someone needs them.

 

[weltersys]

1)Is reaching down to 45Hz really dreaming?
2)Within the parameters of less than 24" per side with 1 port, how can I tune a cab for D130 15" drivers?

1) No, but flat response to 45 Hz won't be happening with a box less than 4 cubic feet with a D130.
2) You can tune it however you like, the lower the tuning, the steeper the LF rolloff will be. There are a number of online port calculators available, or you can use the old JBL nomograph below.