Speaker construction advice?

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Hey, I need to cut 3" diameter holes for my TB 871s, ( i think this is an appropriate hole size, maybe a little bigger?)

Anyways, I have been using a dremel plunge router with a circle cutout attachment I made out of some thin transparent plastic material I found around the house... The problem is that the router base occupies any space 1.5" (radius) from the actual dremel bit so I cant drill a new "pivot hole" into the circle cutout attachment I made in order to accomodate a 3" hole.

I considered buying a 3" circle cutout drill attachment from homedepot or something, but i would still have the problem of countersinking the driver.

Another problem is that the driver leads (i think this is what they're called) are too close to the mounting surround and may cause problems when used with .75" speaker construction material, in my case, MDF. So I'll have make a countersink type cut on the back of the baffle as well.

Any suggestions on how to tackle these problems?

Thanks

EDIT: btw im building bipolar TL speakers with the TB 871s that planet10 suggested... if that helps :p
 
Buy A Real Router

You need to puurchase a real "router" and a circle cutting jig. If you call Woodcraft they sale both and you'll need a sprial dual fluted carbide 1/2 shank router bit for cutting the wholes

The other method is to make a template of the speaker and use the template to cut the recess for the speaker then cut the hole.
But the guys a Woodcraft can explane this to you when you buy the router. It a got to have item for building speakers.

Don't buy power tools from home depot, they will give you poor advise. Also if you in Atlanta try Highland Hardware.
 
A circle cutter like this will cut your holes. It would also make the template for cutting your shoulder cuts on the rebates (using a pattern maker's bit) with your router.

Round over the back of the driver coutout with a 3/8 to 1/2" roundover bit to let the driver breath better. Use a rattail file to cut small groves to accomodate the leads, or carefully bend them just enough to fit.

You might try to build a router table for your router as well, make it so the router with your custom base drops in from above. This makes changing bits easier. Consider a large enough base so another, larger router could be used as well.

This will give you more options for pin placement and safer control when working with smaller pieces. Do a search on router jigs, there are many great ideas out there, and be sure to read the saftey tips.
 
Cut the rabbett first, 3 5/8" diameter, 1/8" depth. Then cut the hole 3". On the inside of the front baffle use a roundover bit to create a "butterfly" for air to get to the driver. This will also help get some room for the terminals. I use a Porter Cable plunge router with the Jasper circle jig. Perfect cuts every time.
 

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frugal-phile™
Joined 2001
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The budget method is to use the appropriate size holesaw, and then build up the front baffle with woolfelt to get them flush.

Another method is to rear mount them -- you have to put at least a 45 degree slope on the cutout.

The 871 was a development of a different driver because the distributor wanted the fancy round bezel instead of the pincusion frame... personally i'd rather have the pin-cushion.

dave
 
I dont want to sound too amateur, I have built many speakers in my short time on theis earth from pro audio cabs to small hifi bookshelfs, but I havent yet managed to aquire a router. (Will do very shortly though I think - I appreciate how essential they are to a good job.)

However careful measurement, a compass, and a jigsaw do work wonders. Ive made some howlers through not measuring enough/ being overconfident but the last cab I made had many circular holes (3 per cab.) I made all pretty much spot on with this method.

At the end of the day its all about practise, I make solid cabinets now, but didnt always use to!
 
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