BillFitzmaurice.info

Hi everyone,
I've got the plans, the speakers and all the timber cut to the right sizes bar a few of the smaller items like the bracing and backplate flanges.

I've never built boxes before, although I built some drawers a couple of months ago. So I'm a little nervous about cracking the lid off the glue and getting into it. But the time's come! I'm building them both at the same time rather than one then the other... I feel like I've got a pretty good feel for the plans.

Here's all the mouth/baffle panels cut out and ready to go. The guide boards above I've protected with some wax paper so they don't glue to the job. I'm using a brad nail gun rather than screws.

Anyone have any experience with or words about the wisdom of finishing with a dark stain and varnish or shellac? I'm curious about the idea and how it would wear and the like...

more pics and stories to come soon

Ok, so a couple of other threads here seem to indicate that high quality finishes will just prove a source of frustration once you throw them in the back of the car a few times.

Anyway the build continues apace, more photos below. So much glue, so little wood...

I'm a bit concerned about the next step, getting the top on to cut off the excess mouth panel. Not sure whether to nail and glue it before doing this, or just to hold it in place with clamps.

I'm also wondering about the low pass filter (i'm building this as a bass rig so no piezos). While I'm ok about the idea of the lp filter dropping the impedance and increasing the response in the hi mids, I am a bit concerned about the 2 kHz cut off, since the drivers themselves respond up to about 4 kHz. Aren't I then giving up the extra 2 kHz in response that I'd otherwise get for free? Should I consider changing some of the component values to raise the rolloff point? Or am I being concerned about things I won't hear? I guess it's also a pretty harsh part of the spectrum in that 2-4 kHz range, I'm open to suggestions here.

more to come...

I love the way these sound.. Nice looking build

looking good! Keep going.

TwoTone wrote:Aren't I then giving up the extra 2 kHz in response that I'd otherwise get for free?

Nope.

TwoTone wrote:Should I consider changing some of the component values to raise the rolloff point?

Nope.

TwoTone wrote:Or am I being concerned about things I won't hear?

Yes.

It tames the rising response of the woofer smoothing response, not costing response.

Ahh, of course. That pesky peak between 2 and 4 kHz on the Eminence 2512. This makes sense to me now.

Thanks

TwoTone wrote:the drivers themselves respond up to about 4 kHz.

Not off-axis. Axial response alone is moot. If you want more high end add an array.

So I was trial fitting the drivers today and wondering about a couple of things.

How tight should I compress the gasket? I guess it just needs to be airtight.

Should I be removing the rear gasket so that I can screw down directly onto the speaker frame or just be leaving it there and compressing it?

I'm really happy with how the tops went on, the sides seem to be totally square so it should just be a matter of clamps and glue now... then the hardware.

Be sure to give up glue in favour of PL when you get to building subs. Hopefully you won't have any whistles in your jacks.

The glue I've used is a polyurethane expanding glue as specified. Bubbles up and expands as per all the information I've seen here.

But yes, hopefully I've used enough of it and all the joins are perfectly sealed. I think that I read in one thread about using a straw to listen for leaks, so I will give that a try. I'm mostly concerned about where the baffle is joined to the mouth panels with the grill in between but I've used plenty of glue there and it's expanded out both sides, so I'm hopeful !

TwoTone wrote:The glue I've used is a polyurethane expanding glue as specified. Bubbles up and expands as per all the information I've seen here.

Not quite the same. You're probably okay with tops. PL does not bubble like the Gorilla stuff. Don't risk it with subs. Personally I can't stand any of the bubbly poly's, I'd rather use old fashioned yellow glue than them.

TwoTone wrote:The glue I've used is a polyurethane expanding glue as specified.

The specified PL Premium does not bubble. Don't screw up a sub build for the lack of a three dollar tube of adhesive.

Too late, I glued the sides on last night. Here's some pics of the glue, one from where it's still in the join, the other from a piece that I took off with a scraper.

Here's a link to some info on the glue.

http://www.titebond.com/ProductLineTB.a ... prodline=6

and the pics... if anyone has any opinion I'd be grateful to hear it, although at this stage I'm thinking that I might as well get the drivers in and test for leaks regardless.

Don't use it on subs.

LelandCrooks wrote:Don't use it on subs.

+1

Splurge for the $3 stuff.