BillFitzmaurice.info

Keryn O'Shea wrote: ↑Mon May 15, 2023 5:21 am

Bruce Weldy wrote: ↑Sun May 14, 2023 7:18 pm chance of a screwdriver slipping and poking a hole in the cone.

Great tip.. are you speaking from experience Bruce?

No, but I had a scare or two......one thing I do now if I'm screwing from the front of the driver is to put one of the baffle cutouts on top of the cone when screwing in the driver. I've got a bunch of those BB discs hanging around from all the speaker builds.

Bill Fitzmaurice wrote: ↑Sun May 14, 2023 8:36 pm 1/4" lags is overkill. What works very well is metal roofing screws, which come in many lengths and have a 1/4" hex head.

I'm not even sure I know what those look like....do they have a washer head?

They do. I always have some on hand for any job where I want to use a screw that doesn't countersink.

Bruce Weldy wrote: ↑Mon May 15, 2023 7:02 am .. if I'm screwing from the front of the driver is to put one of the baffle cutouts on top of the cone when screwing in the driver.

Another great tip.. that one should stop me poking the screwdriver into my finger instead when I'm fitting drivers!

Bill Fitzmaurice wrote: ↑Sun May 14, 2023 8:36 pm What works very well is metal roofing screws, which come in many lengths and have a 1/4" hex head.

Do yours have a fine thread Bill? Nearly used them in an 8" AT for the driver once, as it was late and l wanted to test it. Also liked the washer head for that purpose.

Coarse thread. They're expressly designed for going into plywood, making them ideal for driver mounting.

A lot of progress was made this week.
They are both as far as I can get them without buying more plywood. I checked my local fancy wood store, and blthe 1/2" BB sheets are currently $65 here in Northern Arizona, and very available.

jakkle21 wrote: ↑Thu May 25, 2023 8:53 pm I checked my local fancy wood store, and blthe 1/2" BB sheets are currently $65 here in Northern Arizona, and very available.

Wow, maybe prices and supply are coming back around!

We can only hope. They are now $5 less than they were in January

Yesterday I was cutting panels 5 & 6, a long with bracing, and I had a question. In the plans it says they should be spaced 6" to 9", does that mean I should use however many I need to hit at least 6 and most 9 inches between each other and the sidewalls?
In other words, 4 sets of braces since my cabs are 35" on the inside?

jakkle21 wrote: ↑Wed Jun 14, 2023 6:24 pm Yesterday I was cutting panels 5 & 6, a long with bracing, and I had a question. In the plans it says they should be spaced 6" to 9", does that mean I should use however many I need to hit at least 6 and most 9 inches between each other and the sidewalls?
In other words, 4 sets of braces since my cabs are 35" on the inside?

Sounds right to me....

You could do 3 spaced 8¾", 4 spaced 7", or 5 spaced 5 13/16"

Don't worry about exact spacing. If anything it should be randomized, to prevent resonance.

Thank you for all the responses.
One more question while on the subject, what are the pros and cons of more or less braces?
My thoughts are, more braces gives you slightly more riged and sturdy cabs in exchange for a more weight. Possible slightly reduced performance from lost space, but possibly slightly better from being more rigid.

jakkle21 wrote: ↑Thu Jun 15, 2023 1:44 pm Thank you for all the responses.
One more question while on the subject, what are the pros and cons of more or less braces?
My thoughts are, more braces gives you slightly more riged and sturdy cabs in exchange for a more weight. Possible slightly reduced performance from lost space, but possibly slightly better from being more rigid.

The importance of bracing is often misunderstood.
A tiny reduction in response from lots of bracing is a very small price to pay compared to a -3dB loss from panel flex due to inadequate bracing.
Don't forget if you require lots of mouth braces, you need to add extra braces in the horn path too...

jakkle21 wrote: ↑Thu Jun 15, 2023 1:44 pm Thank you for all the responses.
One more question while on the subject, what are the pros and cons of more or less braces?
My thoughts are, more braces gives you slightly more riged and sturdy cabs in exchange for a more weight. Possible slightly reduced performance from lost space, but possibly slightly better from being more rigid.

If I were building 36" T48's (jealous that you are ), I'd probably do 3 in the mouth, 4 up the back between panels 5 & 8, 3 braces between panels 3 & 5, 4 braces between panels 4 & 6.

Like Grant said, you want the cab RIGID, otherwise output can be compromised. The less panel flex the better. Bill's got it all sorted out. You'll be fine if you follow the plans.

Braces can be made of any quality ply if there's not enough scrap in your BB pile. Can even be done in ¼".