Opening up woofer hole?

[Doc Mark]

Greetings, Friends,

I've been racking my brain as to how I can get "something" together, which resembles my "Dream Speakers", even if I end up changing things a bit as I go on with this project.

It came to me that I have a pair of PA cabinets that I used for many years, each being about 4.5 cubic feet. Currently, I have a die cast CTS 15" woofer in each box, and that, plus a Community horn with Altec driver, was a fine small PA system for many years. I thought that, if I mounted my JBL 2235H woofers in that box, replacing the CTS woofers, and retuned it, that may well sound pretty darned good. I can then add a small box, with JBL 10" 2420 compression driver with horn lense assembly, and the 2405 slot tweeter, to complete the package. This will be bi-amped electronically, and may well sound good enough to satisfy my "needs", while I take more time to find and gather a nice pair of walnut veneered JBL emclosures. Worth a try, me thinks!!

My only problem is that the CTS woofer hole is smaller than that needed by the 2235's. The CTS requires a 13 11/16" hole, whilst the 2235 requires a 14 9/16" hole. This is a difference of 7/8", and I need to open up that mounting hole in the cleanest way possible. I'm thinking about using my router, but it would have to be free hand, and that could really make a mess!! Any suggestions, Friends? Thanks, very much, and God Bless!

Every Good Wish,
Doc

P.S. In truth, I "blame" you folks for sucking me back into my quest to get my "Dream Speakers" together! Until I stumbled upon this site, I was blissfully happy with my little JBL 4408's, and my "make do" subwoofer!!! NOW, all bets are off, and I'm as anxious as a new Bride on her wedding night!!!

[johnaec]

Take a look at this thread where I describe the construction of some stage monitors: http://audioheritage.org/vbulletin/s...ad.php?t=18577

What would work well is to use speaker hole jigs like I did, (pics in the first message of thread), with a plunge router. The jig is larger in diameter than the final hole, to account for the radius of the router guide.

John

[grumpy]

Hi Doc.

As mech986 has just pointed out, I've a few 4333 (not -A) cabinets that
saeman was going to have put to the curb. They are structurally sound,
but... that's about it. They are very ragged cosmetically and have all
plates/crossovers/hardware/t-nuts ... everything removed. Painted, with
quite a few mounting holes on the sides/rear/... these were originally
the gray utility cabs, now black. Grilles are functional, but make-shift.

No space for 10" driver, but 2235's would fit with L300-components.
CC and non-CC N333 equiv crossover designs are posted here somewhere.

Would be a -lot- of work to make them livingroom-able, but possible,
... and they -are- JBL cabinets . Not looking to profit from this, but
would like to see them used as opposed to stored or flipped.

When I bother to make some 2308-type lenses, I'll post some candidates
for best sounding/worst looking JBL monitors With the distressed 2405
sale on ebay, maybe this will start a trend

PM me or talk to Bart if you're interested.

-grumpy

[grumpy]

BTW, If you really need to open up the 15" driver hole, a nice jigsaw
with a good blade and a steady hand will do the job. -grumpy
(sometimes there's not room for a router)

[subwoof]

If you have a router, get a 1/8 or 3/16 rabbetting bit with a ball bearing pilot.

Go around the hole leaving a small lip on the bottom - that lip can be removed with a curved wood rasp ( cheese grater style ) pulled up from the inside. You should ( of course ) remove the T-nuts....

Your goal is 13 15/16 but shoot for 14" to compensate for the rough cut.

This is an old trick we did to install the altec 15 ( I mean 16 ) speakers in cabinets.

sub

[toddalin]

BTW, If you really need to open up the 15" driver hole, a nice jigsaw
with a good blade and a steady hand will do the job. -grumpy
(sometimes there's not room for a router)

Agreed, I've also done this too.

Because you will front mount the speaker (I assume), any unevenness in the edge will not show.

Also, when I do it, I put a layer of masking tape on the baffle to keep the jigsaw from scratching it up. It is also far easier to see the pencil line on the tape.

[Doc Mark]

Greetings, Friends,

Thank you all, very much, for your comments and suggestions! Much appreciated!

As the baffles on these cabinets are recessed, there is not really room to use a regular router, and I was planning to use shims, if I went the router route. Now, I have more to think about, regarding doing it that way.

A jigsaw just might be the way to go, as I can use one in the room in which I have to work, me thinks. Great idea, and one I'd not remembered.

Grumpy, I've sent you a PM, and look forward to talking more to you about your 4333 boxes!

Again, I very much appreciate all the thoughts and suggestions, Friends! I'll let you know how this saga turns out, when I do a little more investigation. Take care, and God Bless!

Every Good Wish,
Doc

[grumpy]

PM replied.

[Doc Mark]

PM replied.

Hey, Grumpy,

Many thanks, and I'll be talking to you soon! Take care, and God Bless!

Every Good Wish,
Doc

[Gary L]

Since your existing baffel is recessed, use a solid piece to match the thickness of the recess. Cut the correct size hole in the solid piece to use it as a template and then insert it into the recessed baffel. You will now have a flat surface for your router and can use a template router bit to open the existing hole to match.

Gary