Introducing: The Pit Vipers (Ooh Yeah!!!)

[eisenhowerj]

Hey all, long time listener...first time caller.
Spring of '21 I built a pair of Classix II from a knockdown kit from PE (https://www.parts-express.com/Classi...112?quantity=2) with the purpose of using them in my office to play LPs. They turned out great and I enjoy listening to them for hours while I work.



Well, my wife wants to use my setup to play her records but wants to listen to them all over the house. The Classix II perform pretty well but we want..... MORE. I go and check the latest speaker designs and what else enters the ring but the PIT VIPERS, YEAAA. I like big woofers and I cannot lie, sorry not sorry.
Annnyway, looking over Paul's notes he said he might've increased the thickness of the front panel and add more bracing. Before I go out to garage and start cuttin' up some mdf I wanted someone to go over my changes:

• I'll be gluing 1/2" MDF to 3/4" MDF to the front and back
• I added 1" of depth to regain the volume lost by above
• Instead of window pane style bracing I will be using what I'll call diamond or diagonal bracing. Diagnoals keep things square.
• I moved the woofer lower and readjusted the mids and tweeters. I plan on putting the speakers on the foam risers that have a 5-10 degree angle so the lows dont hit the floor as much and the tweeters are a bit closer to walking ear level.

Should I add a second diagonal brace below the woofer? I'm thinking its not necessary with the other changes I've made.




Thanks in advance!
John

[djg]

The point of a thick baffle is to have sufficient thickness remaining when you cut rebates for the drivers, and to maintain strength in a panel with big holes. 1/2" more would be good, I think. I wouldn't bother with the back panel, especially if you add two more braces, one between the woofer and the ports, and one between the midrange and the tweeter. One builder IIRC, has gone with what I tagged as "hashtag" braces. I wouldn't do diagonal bracing, but that's based on "feelings", not any data. I like windowpane bracing, but lots of builders whom I respect say the only important parts of a brace tie the opposing sides together in the "middle" of the panels. Bracing is second only to capacitors for "discussions".

[djg]

And I wouldn't cut the speaker holes and rebates until I had the drivers in hand. And the port holes too.

[eisenhowerj]

Yep, I have the components and on my doc it says the specs were pulled from PE but the builder should double check. The image compression is making that hard to read. This is version 0001 so I'm not going to share the pdf until I can say they're optimal.

The "discussions" out there are very lengthy and to be fair, the anatomy/build/age of everyone's ear is different so I take some judgments with a grain of salt. I could use 1/2" of dampening on the back wall in place of the extra MDF I was adding there. I don't think I want to add too much bracing that is attached to the front panel, in theory...to reduce the energy transferred to the back and sides. The woofer is 10lbs (4.5Kg) so the bracing I do have and the extra 1/2" on the front panel will help support that.

Thank you for your responses, they are appreciated.

[djg]

Here's how I did my last project, a smaller 3 way. I would say it has minimal bracing. My bracing is all stick built as I do not have a CNC. Just for ideas, not a recommendation.

https://techtalk.parts-express.com/forum/speaker-project-gallery/1489835-the-lps-r2-jr