Another Big Cheap Array - Holes, holes and more holes.

[chad1376]

I've got another big cheap array in the making. Why do I do this to myself? I don't know, it's fun I guess?

Quick history. I built my first big array about 10-years ago for garage use. It's served me well, but speakers are getting worn. Surrounds are rotting and voice coil leads are fatigued and keep breaking.


Version 2 was built about 4 years ago. It ended up a disappointment. It never had the sound of the first array, developed some buzzing from poor glue joints, and I got tired of cooking the single horn tweeter. I took it out of service, however the bass bins are still going strong. Array #1 was put back online, although it's never worked as it did in it's former glory.


So it's time for another build. Quite similar to Array #1.


On order are 96 el-cheapo tweeters:
https://www.parts-express.com/222604...ohms--289-2272

And 32 el-cheapo 4-inch woofers:
https://www.parts-express.com/4-trea...6-ohm--299-320

I probably won't start making sawdust this weekend. I'd like to get the drivers in-hand and verify dimensions first, since specs for buyouts can be kind of vague.

[thekorvers]

Interesting. Keep us posted.

It is obvious you like arrays as even your parts bins are arrayed!

[Jake]

Those 4" woofers don't look bad, but require a large airspace even sealed. My humble suggestion: dayton ce65w. It's frequency response and price are similar in much less airspace. Impressive cheap driver imo.

[PWR RYD]

I just finished routering rebates and through holes for 6 drivers (MTM towers) a couple days ago. I can't imagine making that many holes.... ever! Good luck Chad.

[chad1376]

I just finished routering rebates and through holes for 6 drivers (MTM towers) a couple days ago. I can't imagine making that many holes.... ever! Good luck Chad.

Yes - holes are going to be tedious. I once had a co-worker with a big CNC router. Too bad he left disgruntled, otherwise I'd be heading to his house with a 6-pack. ;)

The tweeters are especially going to be tough, since the frames are ugly and intended to be rear mounted. My initial plan was to first use a hole saw for the basic openings. Then a 1/4" roundover all around the face, letting the areas overlap across all the holes. Then, I'll hog out the back side of the baffle behind the holes. I know setting the tweeters behind the front face of the baffle in this manner is not ideal for diffraction and all that, but it should look OK if I don't goof too much with the router.

It'll be worth it to make a router template for all the internal bracing too.

Construction will just be MDF with glossy latex - a fine wood finish is not in the cards here.

Edit: as soon as I wrote this, I realized there's not going to be much material in between each tweeter. Hmm, I'll need to think about this some more.

[chad1376]

Drivers are here!

4" woofers look well made.


Tweeters? - As expected, cheap and ugly. A few arrived with a little damage to the cap, but I ordered extra.


I'm reformulating a plan to mount all these little buggers. I'm thinking about aluminum strip, with all the holes drilled in it, then mounting that to the baffle. I'll draw it up in more detail when I get some more time. Some sort of grill or protection would be good to, since they appear fairly fragile.
'
Oddly, there was a package with a new pair of size 20 women's jeans inside all of the packing material. I'm sure that wasn't provided by PE. Very strange. I can only guess the box came apart at some point during shipping, and the worker scooped everything back up (along with the jeans), and taped it all back together. The drivers survived the ordeal.

[djg]

Interesting rendering in post #1. Your woofer order could have met an Alibaba MOQ.

[chad1376]

After a month of work deadlines, X-mass, and getting the garage organized, I'm finally ready to start this project!

My revised plan for mounting the tweeters is to "embrace the ugly." A linear 1/16" relief along the front baffle, and simple front mounting of the tweeters. Some black Plasti-dip in the relief area, and on the tweeter frames. It'll make mounting and wiring sooo much easier, and get the tweeters flush with the baffle.

[chad1376]

I actually got something done. Cut all the major pieces, made a mess with the router, and got the internal braces done. I also bought a 1-1/2" Forstner bit, and gave it a try with MDF. It makes clean and easy holes, so that's the ticket for the tweeters.

[chad1376]

448 hole centers measured and located with a punch. This weekend: Find a good audio book, turn on the garage heater, and spend some quality time with the drill press.

[chad1376]

Holes !

[m3gunner]

Awesome! 448 holes? How many speakers did you do?

[chad1376]

Awesome! 448 holes? How many speakers did you do?

32 woofers, 96 tweeters, and 320 pilot holes

[chad1376]

For the grill - I'm going to mount some expanded steel, spaced 1/4" in front of the baffle. The garage environment is not friendly to fragile speakers (broom handles, kids, bicycles, dogs, etc.) This will also save me from the need to rebate the speakers for aesthetics. After a whole day cutting holes, I'm a little nervous to 'f up all my work with a router. The portion of the grate over the tweeters will be cantilevered over the drivers, but this is tough stuff, and it would probably take a flying sledgehammer to bend the grill.

[philthien]

Quick history. I built my first big array about 10-years ago for garage use. It's served me well, but speakers are getting worn. Surrounds are rotting and voice coil leads are fatigued and keep breaking.

I find this aspect (voice coil leads breaking) fascinating. In a speaker with so many drivers, I'm amazed any of them are actually moving that much.

OTOH, I see a rack with what appears to be quite a bit of power.

Looking forward to more progress on the new build.