[That dude]

I've got a pair of old jbl full range car speakers. I was thinking of building an enclosure to house it in and use them as a pair of monitors for my keyboard/computer rig.

Ideas?

 

[chesterqw]

i was thinking of getting those huge magnets out...
but yea, making an enclosure for them is nice too.

 

[Good Times]

Could do something like those John Blue monitors. Simple rectangular box and treat it to a nice gloss finish?

I've got a spare pair of Boston Acoustic 4" splits from back in the day, thinking of making some scale replicas of my B&W DM6s. A bit more effort involved though.....

 

[Uncle Erik]

Singledrivers? Toss them into a Voight Pipe cabinet and see what happens. If you don't like them, you can always drop a pair of Fostex or other drivers into the cabinet.

 

[That dude]

Them Voight Pipe cabinets are hugemongous. I'm looking for something bookshelf sized. I like the gloss idea, but I don't know how to do that cause I'm a speaker DIY neophyte. Do you guys know where I can find tutorials?

 

[krmathis]

Yeah, building a cabinet for them sounds like a nice idea.
I did that myself some 10 years back and the result was quite nice.

 

[Zigis]

Car speakers usually are designed for open ear.
So you can build simply open baffle or open box.
Or very, very huge sealed box.

 

[Paul J.]

They likely have a high-ish Qts, and possibly VAS. If you want a bookshelf, I'd start with whatever size seems tolerable to you, bigger is probably better. Make the cabinet wider than they are deep and place them against the wall (though not touching, if you end up going aperiodic), so as to alleviate the need for baffle step compensation. I would use 3/4" plywood (as void free as possible, Arauco ply is really cheap and works very well, that veneered stuff from Homey-D's is terrible and will cause you headaches!).

Stuff them decently with polyfill, put the drivers in, and see what happens. If they sound too ripe in the bass, try more polyfill (effectively increases the cabinet volume). At some point, you'll get too much stuffing and it won't work at all well (congested sound, no dynamics). If they sound too lean (which is unlikely to happen), try removing stuffing. If they are still too lean, put stuff in the cabinets (bag of beans).

There is a solid chance that no matter what you do, you'll end up with a big hump in the bass (as a result of the high Qts). Then, start drilling holes (1/4" maybe) in the back of your cabinet (start with several). At some point, the bass will flatten out. If you go too far, you can always cover some holes back up. You are making an aperiodic cabinet, which basically means a really lossy box that behaves like a very large sealed box and has the added benefit of flattening the drivers impedance peak. You can also put something resistive over the holes, like used dryer sheets. They'd look better on the inside! You probably won't ever get a ton of bass (some car drivers have pretty high Fs's), but you can certainly achieve a nice flat response.

If you want crazy ideas for tune-able vented boxes or transmission lines, I'd be happy to share some. But, the sealed-turned-aperiodic as necessary is pretty much guaranteed to create something listenable.

Paul

 

[That dude]

^Wow, that is certainly a substantial reply, thanks so much. From what I gather, deeper and bigger is better? I did not understand most of what you mentioned and I googled every other word...

Anyway, without cabinets, they do sound fairly thin and lifeless, sort of 2 dimensional. The bass isn't focused and the the mids are also all over the place while the highs are attacking you straight in the face. Maybe this could help you understand the speaker's sound a little more?

 

[Paul J.]

Don't worry about the lack of bass when they are by themselves, that is entirely the result of dipole cancellation. And, the ear often perceives a hole in one place as a peak somewhere else, so, your dislike of the treble could well the result of not having them in a box! Fullrange drivers are always directional, but that isn't necessarily a bad thing. It means they aren't as picky about room interaction (in the treble), and you can adjust the high frequency balance by changing the toe-in angle.

But, to distill my earlier post for you: build a bookshelf sized box that is wider and taller than it is deep. Cut a hole for the driver (before you glue the box together, as the driver hole is an easy thing to mess up), and come up with a way to connect some wires.* Put some polyfill in the box. I suspect you will then find that you've got sloppy and excessive bass. Drill a bunch of small holes in the back of the box until you like the sound. That's it!

Paul

*Radio Shack has terminal cups, I'd avoid the spring variety.
**Polyfill is polyester pillow and upholstery stuffing. You can find it in the crafts isle. It is sometimes cheaper to just gut the least expensive pillows.