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4Pis are better now? [message #77460] Fri, 09 August 2013 14:11 Go to next message
Duncan McBride is currently offline  Duncan McBride
Messages: 41
Registered: May 2009
Baron
Hey everybody, it's been a while.

I built a pair of 4Pis almost ten years ago, and I've really been enjoying them, but now I would like to upgrade to the new waveguide and crossovers. Thing is, ripping all that out of the old enclosures left me thinking I should build new cabinets too.

This time around I would like to use particle board instead of MDF. The dust from cutting MDF really bothers me so I tried the particle board for a pair of 1Pis and it doesn't seem as troubling. The 1Pis sound just fine. Actually, the particle board seems to be easier on my saw and other tools. So I'd like to continue with it on the new 4Pi cabinets. Should I be doing anything different with particle board, like bracing or damping, or treat it just like MDF?

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Re: 4Pis are better now? [message #77462 is a reply to message #77460] Fri, 09 August 2013 15:09 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18784
Registered: January 2001
Illuminati (33rd Degree)

Those are nice looking one π's, Duncan. Congrats!

As far as the H290C waveguide upgrade, it really isn't too bad. For many people, it's a bolt-on replacement, with a couple easy changes to the crossover. For some, the baffle cutout has to be opened up slightly, although the router groove for flush mounted cabinets is the same. So trimming is easy to do with a four-in-hand, if needed at all.

Re: 4Pis are better now? [message #77463 is a reply to message #77460] Fri, 09 August 2013 19:25 Go to previous messageGo to next message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
Illuminati (2nd Degree)
Guy came to me at work last week with a beat-to-krap KLH Model 6 (what a great speaker!) looking for re-build advice. Turns out he has 4 of them bought new in the early 70s.

Reminded me what great speakers were made out of particle board back then.

Doesn't change the fact, tho', that PB has brittle edges that makes veneering difficult and doesn't hold screws, or even T-nuts, well.

I also hate MDF, same reasons as you but have gone to Arauco Plywood, no longer available in my area, which leaves Baltic/Finnish/Russian Birch. Expensive but worth it.

Do you really need to re-build those cabinets?
Re: 4Pis are better now? [message #77468 is a reply to message #77463] Fri, 09 August 2013 22:10 Go to previous messageGo to next message
Duncan McBride is currently offline  Duncan McBride
Messages: 41
Registered: May 2009
Baron
Yeah, maybe they're not so bad after all. Razz I won't throw them away until I find something for new ones. I tried the particle board after I dug out some Boston Acoustic A150s I bought in the early 80's. Never could let those go. Particle board cabinets are still ok, but the bases are crumbling - had them out on a screen porch for a while, and in Florida that's like leaving things out in the rain.

I'd like to try HeatLock to put paper backed veneer on particle board. Anybody have any experience with that?
Re: 4Pis are better now? [message #77469 is a reply to message #77468] Sat, 10 August 2013 06:43 Go to previous messageGo to next message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
Illuminati (2nd Degree)
I have a half-gallon of Titebond II left over from my 2Pi Towers you can have Rolling Eyes iron-on veneering was a disaster for me! "Bubble, bubble, toil and....."

Cold pressing with Urea Formaldehyde PPR is still the king of glues, especially with multi-leaf glue-ups.
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Requires a lot of clamps, a lot of time and making cauls and platens to cover each side as you clamp it up....or invest in a vacuum bag press system.

Next best is contact adhesive with NBL veneer. Use a 6" long piece of soft pine 2x4 to press out (press hard!) the veneer after mating the surfaces. Contact also works just fine for curved cabinet edges.
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For the weekend DIY'r this is the best. My 4Pis have no issues 5 years later.
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Re: 4Pis are better now? [message #77470 is a reply to message #77469] Sat, 10 August 2013 12:40 Go to previous message
Duncan McBride is currently offline  Duncan McBride
Messages: 41
Registered: May 2009
Baron
I had to look up NBL. Those 4Pis are inspiring, Bill. Now I need to add a room to the house. Thanks, man.
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