[Dave Elliott]

Jeff,

Thanks. I don't know if it belongs in any magazines, but I'd wager it'll knock the pants off of most of the other $5-6K systems.

Jeff is right. Adding 7.1 was really a huge improvement. Even with regular 5.1 sources the receiver does a very good job of matrixing a rear channel. If you're at all considering a 7.1 upgrade, DO IT!

Sounds like the speaker project has begun in full force. Nothing like a snow-day to start a project. Of course, your discussion is way over my head I'll just nod when you explain it to me.

What does everyone else think of the setup?

-Dave

[Hank Frankenberg]

Dave, you have a nice setup there - congratulations!

[Jeff Meininger]

I just figured out how to model a 2nd order 80Hz sub crossover in LspCAD (thanks Mark!!), and it turns out my 2-ways will hit max excursion at 103 dB @ 88 Hz and my MTMs at 109 dB! I don't think I'll ever even explore that territory. I'm certainly no longer worried about SPL limitations. Yeehaw!

Next, I'll view the summed response between the sub and these speakers and see what integration looks like.

I'll probably end up getting a Harman Kardon AVR525 and sell my Onkyo SR500 to my folks who are setting up their first HT. (I'm also building them a Stryke AV15 sub!) I wish the HK manual gave crossover slope specs. I understand that higher-end receiver sub XOs are sometimes mixed-order affairs, and if that's the case, I'd sure like to know before I spend a bunch of time agonizing over modeled responses.

[Jeff Meininger]

Here are a few pictures of a couple of my in-progress cabinets.

Every pound helps... Sit, kitty, sit! (or, "need more bar clamps")


The back of one of my TM surround baffles. Tee nuts for the tweeter and PE's hurricane nuts for the woofer. The woofer shares one tweeter hole.


Cabinet brace clamped into MTM tower. Top, bottom, and sides clamped together for shallow surround enclosure.



Lessons learned so far:
- Freakin' Home Depot doesn't make square cuts! ARGH!
- You can't have too many clamps.
- I want a table saw.
- The yellow MDF is easier to work with than the reddish MDF. (?)
- That little arrow on the router? That's the direction of rotation, NOT the direction you move the router. (I broke my MLCS carbide spiral upcut!)
- Can-Do clamps are neato.
- The bugs come out at night in the garage. Little footprints running every which way in the thin MDF dust layer.
- Measure twice, cut until you get it right.


So far, so good.

[Hank Frankenberg]

"- Freakin' Home Depot doesn't make square cuts! ARGH!"

Always assume they don't, and make your cuts referencing one of the factory edges.

"You can't have too many clamps."

How true!

"I want a table saw."

You WILL lust after a table saw until you get one.

"The yellow MDF is easier to work with than the reddish MDF."

Reddish MDF? Where in the world did you buy reddish MDF???

"Measure twice, cut until you get it right."

Hey, MDF is cheap.

[Mark Hayenga]

I think I know what Jeff means by yellow v. red. The yellow is easier to cut, route etc. I think it's also a smidge lighter than the red stuff. I don't know who makes what but I've found both 'versions' at Home Depot and Lowes (though the Lowe's in my hometown Bryan always has the red stuff).


Mark

[Mark Hayenga]

Also, after much investigation, Jonathan and I have determined that 'measure twice, cut once' should actually be 'measure twice, cut once, swear, measure a third time, cut twice, lose finger, swear again, spend the night in the emergency room'.

[Jeff Meininger]

I wasted half a sheet of MDF before I realized the Home Depot cuts were wacky. Many of my panels ended up trapezoidal, so I could have made a "fun house" type speaker that leaned to one side and backward.

I got a big contractor's T-square after this realization. I had been using a silly plastic rafter square and a long straightedge, which wasn't nearly as accurate.

Home Depot ran out of the yellow MDF that I'm used to seeing, and re-stocked with something that is a bit reddish by comparison. It's a subtle difference, but the sawdust doesn't even smell the same. Just another brand I suppose. No matter how hard I try, though, I scorch the heck out of the red stuff when I'm cutting with the circular saw. The yellow stuff cuts so well (even with a dull blade) that I have to mark the factory edges to be sure I don't forget which is which.

This whole project would be going much faster if I had more bar clamps. I have a bunch of cut panels waiting to be glued, but I don't want to take off the clamps until that stuff has REALLY cured.

I went to Home Depot to buy more bar clamps, but I found that I can buy 4 clamps at Harbor Freight for less than the cost of 1 at Home Depot. The Home Depot clamps are obviously of higher quality, but I'd rather have 8 crappy clamps than 2 nice ones.

[Jonathan DA]

"Measure with yard stick, mark with chalk, cut with chainsaw."

Jeff, check eBay for clamps, you can get bar clamps for as little as $3 each if you buy a box of them at a time.

Mark, I think Jeff had a two to four channel night with his off square cuts.

[Jeff Meininger]

My inside-joke detector is beeping.

I can't glue and clamp the back panel onto the enclosure until I wire everything up.

Two questions:

1. I'm afraid of messing something up when soldering. The leads coming away from the tweeter terminals are just slightly thicker than human hairs. Should I use those slide-over-the-tab connectors that PE gave me in their woofer mounting kits? That seems like a lame thing to do when you could just solder directly.

2. I have to install the binding posts before the back panel goes on because the nuts have to be tightened from the inside. I'm planning to use a foam roller to paint, so I have to paint the back panel first since "rolling around" the binding posts is impossible. SO, I have to clamp my finished panel onto my enclosure. What do I do to protect the paint? Put a towel between the panel and anything that's going to be touching it (clamps, sandbags, etc)?

Umm... another question:

My plan is to veneer the top and sides "some day", but paint the baffle and the back panel NOW. I will use Kilz primer, and then go back over with 2 coats of oil-based flat black enamel with a foam roller. (Spraypainting is just too dang time consuming.) Oil-based enamel should lay pretty flat, but I imagine there will be some amount of very light texturing from the roller. Is this okay on the baffle?

Thanks!

[Hank Frankenberg]

the sawdust doesn't even smell the same

Jeff, 3M makes some really good dust masks. Not to scare you but word on the street is that MDF dust is CARCINOGENIC.

Tips (no charge):

I have clamps if you want to borrow some.

Use proper size push-on female connectors on the wires going to your tweeters. Carefully squeeze the terminals to close down the gap a bit so when you push them on the tweeter terminals, you'll get a gas-tight electrical connection.

For cabinets not veneered on the back, I like to use black laminate on the backs. It's fairly quick and avoids *paint* (yuck).

Tighten the binding post nuts on the inside of the cabinet, and then put some glue on the post threads/nuts to help keep the nuts from loosening (I usually use Liquid Nails).

You're an adventurous guy, so keep on truckin'.