BillFitzmaurice.info

Hello all,

This is my first post, and my first BFM builds. I’m building a pair of TLAH’s for front mains, a 9 driver horizontal SLA for center, and a pair of 6 driver SLA’s for the surrounds. I also plan to add a Tuba HT. These will be upgrades for my outdoor theater, 10’ screen hung on the house, viewed on a 24’w x 18’d concrete patio. I’m also lucky to have a corner for the sub.

I have a question about glue. All the BFM plans I own say to use the PL premium except the SLA plans. Is there a reason for this? Was this an oversight?

I built the boxes for the SLA surrounds first as they seemed the easiest of the bunch, and I wanted to try to miter all the edges so there would be no exposed plywood endgrain at the corners or along the baffle. I used the quick grab PL Premium to help keep all the parts from sliding round while I brad nailed. I’ll need some wood putty here and there on the corners but I’m happy so far.

When I build the horizontal SLA, would I be better off with wood glue, or should I use the regular PL? I’m using 3/4” solid Maple for the baffle pieces, with the rest plywood with veneer to hide the end grain, and I plan to finish all the cabs with a black stain and multiple coats of satin polyurethane.

Thanks for any insight,
Dom

Hi and welcome to the forum

Can I suggest you edit the first post, in particular, the title, so people wanting to read about a TLAH or SLA HT build will know what they're looking at?

I imagine it's an oversight, PL premium is amazing adhesive, very forgiving.

Don't stray to far from the plans. Most people are going to finish the cabs somehow, so mitred corners generally aren't required, but they do look nicer.

Enjoy your build(s), post lots of pics, and if you need help, ask questions before you do something (not after), and wait for a reply.
There's usually someone around...

Thanks for the welcome, title changed.

Welcome to the forum!

PL Premium is the suggested adhesive because it expands and seals the joins so that they become air tight (critical). If the joins are not air tight, then the air leaks cause lowered output in the lower frequencies, which can lead to blown drivers because the amp was turned up higher to compensate.

The SLA are small and simple, so the expanding property of PL isn't critical as it is with the more complicated builds.

Thanks Bill.

Concerning the TLAH cabinets, can they be built without the ‘lean-back’ taper to the sides? My application doesn’t need it (I plan to mount them to the screen frame and angle them down towards the listening area), and the build will be simpler. What would be an ideal internal depth, and would this change the size of the port?

Thanks again,
Dom

The taper is necessary because without it you'll get unwanted resonances. There is no port, it's a transmission line terminus.

Bill Fitzmaurice wrote: ↑Tue Apr 21, 2020 11:38 am The taper is necessary because without it you'll get unwanted resonances. There is no port, it's a transmission line terminus.

Thanks again Bill. Stick to the plans it is.

hello
the tlah's and sla's are great ht speakers, you'll love them.
the THT is also an increble ht sub but it is my understanding that it is meant to be used indoors. i could be wrong but i would use t60 or t30/45 if i was building an outdoor HT. please correct le if i'm wrong about this.

greetz ketoet