BillFitzmaurice.info

I bit the bullet and now have 4 THT's underway. The Dayton drivers are in my basement waiting to be broken in. 1/2" Baltic cut up per the cut list. Side panels marked up with the dimensions. Picked up PL Premium and nitrile gloves today. A tip, I found some "plugs" for adhesive/caulk tubes in Home Depot, very long center pin with an airtight seal on top, they should work, I'll report on the effectiveness.

The THT's will go into my 24 x 26 bat cave home theater to replace eight 12 inch sealed subs. Yes, I know that 4 THT's will blow the walls out but it's not about the volume it's all about smoothing the room response.

Amplifiers are already in place can run 450watts into 4 ohms without breaking a sweat.

Deviation from plans, none, if it ain't broke leave it alone. I'm building to a nominal 24 inches wide, these 70 year old shoulders can't pick up much more weight than that. I will use a piloted router bit to finish the access panel opening after panels 1,2,4,5 are in place, I'll use a temporary hot glued spacer for the 1/2 inch set back from the front panel and cut new panels to fit the openings, I bought enough plywood to allow for one or two f ups.

Pictures to follow in future posts.

Thanks to all those that have posted their build threads, big help in the decision to go ahead with this build.

AWESOME! It's not often that one hears about a 70-year old running subs in their home; usually 20-40 year olds.

Old Mike wrote: A tip, I found some "plugs" for adhesive/caulk tubes in Home Depot, very long center pin with an airtight seal on top, they should work, I'll report on the effectiveness.

I bought this one, it works alright for awhile. The PL tube pressure will blow this tip off the tube unless you store the gun placed with the tip down (lean it against something), to provide some weight on the tip to keep from popping off. Then it works great . If it blows out and you get PL between the pin and the cap, it is almost impossible to get the dried PL out to get the good seal again. Still, this cap works better than nothing.

caddylackn wrote:

Old Mike wrote: A tip, I found some "plugs" for adhesive/caulk tubes in Home Depot, very long center pin with an airtight seal on top, they should work, I'll report on the effectiveness.

I bought this one, it works alright for awhile. The PL tube pressure will blow this tip off the tube unless you store the gun placed with the tip down (lean it against something), to provide some weight on the tip to keep from popping off. Then it works great . If it blows out and you get PL between the pin and the cap, it is almost impossible to get the dried PL out to get the good seal again. Still, this cap works better than nothing.

A tip shared by DJP is to wrap the cartridge with tape from top to bottom. I found that this works quite well after a few squeezes. Release the rod tension just before finishing the laying of the PL strip and there is virtually no drips. A 10d nail is a cheap plug.

OK I'll try and post some photos here, spent several hours in the shop today. Primarily finished up panel 4 for each unit, I have an extensive workshop, one advantage of 70 years is the time to accumulate the toys!!! Shots are, in reverse order.

My Jasper Jig ready to make those baffle cut outs,

Some tools used, I had a hinge screw centering bit that perfectly centered pilot holes for the intended socket head wood screws now on their way from Parts Express.

A finished panel 4 with the backer blocks glued and pinned to the back of the panel

A dry fit of panels 1 and 2.

I have some excellent right angle "jigs" from Leigh Valley that I use for cabinet construction. Note the try square, it's a genuine Starret and worth every penny. I have tried the cheap Chinese knock-offs of a lot of tools from home depot, useless. One thing I have learnt is that good tools are not cheap and cheap copies are a false economy.

Yes that is an aircraft under construction in the background.

More to follow. Need to take a couple of days off starting tomorrow, I have a part time consulting job that keeps the grey cells active.

Old Mike wrote:I have an extensive workshop, one advantage of 70 years is the time to accumulate the toys!!!

Yes that is an aircraft under construction in the background.

So in these 70 years you've been putting planes together?

You seem to know what you're doing and are going to follow the plans so I expect this to be a zero drama thread, I can't wait to see the end result. Do you have photos of the existing sub setup? I can't imagine 8x12" sealed subs take up a particularly small amount of space.

I struggle to fit a table saw, tools and bikes in my garage, let alone a light aircraft!

It's Amurica. I'd be surprised if you can see the neighbours.

Its Canada, and you're right I don't see any of my neighbours, we're all on 20 to 40 acre parcels. No issues with noise complaints although the THT's may make a liar out of me!!!

The aircraft is the longest running project I ever had, pushing 30 years, children, work and other hobbies got in the way. I figure I've got about 2000 hours into it so far. It taught me patience and the need to do things right the first time, can't afford a dodgy glue joint at 10,000 feet.

We moved to an acreage when I retired, in no small part because like most people I was always trying to work out of a compromise single or double car garage so I built my dream 1200 sq. ft. shop. No complaints from SWMBO, for the first time in almost 40 years she has been able to park her car inside our attached 2 car garage.

I'll take some photos of my existing home theater set up and post them here in a couple of days, that was the other thing on my bucket list, a no holds barred bat cave

I hope there are no dramas, almost had one on the panel 4 work started gluing the backer blocks on the wrong side, realized after just 2 and so was able to pull them off without any damage.

I'd be interested in hearing what other people have done for equalization I have a calibrated Behringer microphone with a reasonable focusrite USB soundcard and a collection of software including ARTA.

I have a spare input and 4 outputs on a mindsp 4x10HD that I will be using to try and get close to a free air flat response, just hope the local bull moose doesn't try to mount the THT

I then intend to let my Lexicon MC12HDEQ handle the room modes, it does a pretty good job with my existing subs.

Old Mike wrote:
I'd be interested in hearing what other people have done for equalization I have a calibrated Behringer microphone with a reasonable focusrite USB soundcard and a collection of software including ARTA.

Someone will correct me if I am wrong, but with the THT for equalization, all you need do is set the low pass frequency that matches the rest of your system and you are done. You don't need a high pass subsonic filter. You might be able to boost some sub 25 Hz up with equalization, but better to just build your speakers wider. You do need to match to your other home theater speakers for volume, but you can do that with the sub amp gain. If there is other EQ you can do, please educate me. I remove room nodes by trial and error with the sub placement.

Old Mike wrote:I hope there are no dramas, almost had one on the panel 4 work started gluing the backer blocks on the wrong side, realized after just 2 and so was able to pull them off without any damage.

Yeah, it doesn't make much difference if you spend a long time cutting the perfect piece of ply only to glue it in the wrong place - done that a few times.

Old Mike wrote:

Charles Jenkinson wrote:It's Amurica. I'd be surprised if you can see the neighbours.

Its Canada, and you're right I don't see any of my neighbours...

I lol'd

Qty (8) 12" sealed subs, awesome! But 4 THT's will be awesomer ( I think that's a word in Murica).

I'd have to agree on the nail as a PL plug. I use a 4" drywall screw and just chip off the dried bits from time to time. And yes, I have to store it nose down to keep the PL from blowing out the screw.

Build looks great so far, looking forward to your pictures!

There's another way of looking after your PL.

In addition to wrapping it in tape to slow down/stop ooze, rather than a nail etc, I wrap mine in aluminium foil.
Tear off say a foot. Fold it in half. Fold it in half again, this time over the nozzle, beginning at one end. Roll it around the nozzle until it's all rolled up.

Any ooze builds up in the wrapped end, and doesn't set. And you don't end up with any PL on your fingers trying to put the nail back in.
I take my PL out of the caulking gun at the end of the day and put it in my shed/workshop fridge...

howiez wrote: I'd have to agree on the nail as a PL plug. I use a 4" drywall screw and just chip off the dried bits from time to time.

I use a 1/4" lag screw. The smaller the nozzle opening the more pressure there is pushing the PL out.