BillFitzmaurice.info

Having built a pair of 24" T30s and a couple of OT12s, I have felt a couple of times that the system was lacking in 'offensive' volumes which the dance music crowd appreciate (including myself ). My IT contract that I have been working on for the last year is expiring in 2 weeks, so I thought it best to use the time off to build another couple of subs. I didn't want to build another identical speaker at 24" wide, so I decided to build a couple of slim T30s (= 16" = the minimum for Lab12s), and see what they sound like compared to the 24"s - although more importantly, see what they sound like WITH the 24"s

As I will be until I get paid in about 10 days, I am currently only really doing prep work. I have an 8x4 sheet of 9-ply BB (minus a V-plate-shaped 'bite' out of it), so I will be using that to get started on panel 3 as well as some braces and whatever else I can squeeze out of the sheet. I will attempt to make the most labour intensive bits before the contract end, so that assembly will go much quicker once I have all the bits. I am hoping to do a party with them a week after I finish my job, but I have a distinct feeling that this will be too soon and I won't be rushing them even if I have to delay the party for a week (or 2!).

So, that's all the basics of the build. Onto panel 3. I thought I should share my tee nut experiences in case I can help anyone in mounting theirs. When I have mounted tee nuts in the past, I often ended up with the teeth bending, so this is what I do to avoid this. I firstly drill the bolt holes (which I never seem to be able to get accurate, therefore I have to break out the sandpaper to avoid cone slap). This is done with a 6mm drill to match the bolts. After this, I separate the baffle from the spacer (at this point, they are only held together with 4 screws), and redrill the bolt holes in the baffle with a 7mm drill to provide space for the tee nut to sink into the wood. Then I drill 4 small holes for the teeth to sink into like so:


Then I use a long bolt and get it through the hole and out of the other side. I then screw a tee nut on this bolt (note the lining up of teeth and holes):

NOTE: Pretend that there is a bolt going into the tee nut - I didn't get a pic!

Then I use a pair of beefy pliers (don't know the correct term for them) and hold the tee nut exactly where the holes line up with the teeth:


I then use a 10mm socket and wrench to start pulling the tee nut into the wood. When it has a few mm to go (1/16"), I get out the epoxy and slap it underneath the nut like so:


Then STILL HOLDING ONTO THE TEE NUT WITH THE PLIERS, I continue to drive the nut home. I hold onto the nut with the pliers until the last possible moment, otherwise bent teeth and a bust tee nut is what usually results Once done it should look something like this:


Wait for the epoxy to dry and then you can drill some small pilot holes and then drive a few "Harley Screws" home to really make sure. Then a slather it all over with some more epoxy for good measure (as you really don't want these suckers EVER coming loose... trying to get to them once the sub is built would mean chopping into the cab and a total PITA).

NOTE: Picture is pre-slathering!

I figure that my(?) method of pre-drilling the tee nut teeth holes makes the tee nuts less likely to bend (as I originally had big problems getting them to bite cleanly into BB). Even if your holes are not perfectly lined up with the teeth, it provides a 'weakness' in the wood which the tee nut can exploit. In this instance the teeth will displace the wood in its way into the void of the drilled hole and a nicely seated tee nut will result. I am slightly worried that this weakness may make the tee nuts slightly less secure then if you just tried to drive them home without these holes, but once you drive a couple of screws into the assembly, it will 'tighten' up (compress) the wood and close any small holes/voids in the wood.

So overall progress this weekend (slightly slowed down by mysteriously throwing up this afternoon - no idea why, it came out the blue after I was round someone's house fixing their PC for a little extra speaker money!).

Both panel 3s almost completed. One of them is missing 2 tee nuts (I ran out ) and 'Harley Screws'. I decided to use the circular spacers, as I now know how to use my router a little better (last time it was a jigsaw job!).


This is how much BB I have left. Should be good for a few braces:


Finally, I am finding that it is much more enjoyable this time (although it was enjoyable last time)... I think this helped which obviously I didn't have on my first build!

AND YES... I know the placement is off

Oh, and before I forget... when attaching the driver once the sub is complete, should I keep going on the bolts until the metal frame of the Lab12 is touching the wood of the spacer? This is how I have done it on my first 2 subs, but I have never been 100% whether this is correct or not. I assume when using the screw mounting (i.e. recommended) method, this would almost be an impossibility to get it this tight.

And another thing I noticed tonight... what is to stop air from getting from the horn into the rear chamber via the thread gap between tee nuts and bolts? Should I be adding something to the bolts to ensure an airtight fit? Again, this wouldn't be an issue with screw fixings.
Many thanks as always. Can't wait to let rip with the 4 subs!

escapemcp wrote:
And another thing I noticed tonight... what is to stop air from getting from the horn into the rear chamber via the thread gap between tee nuts and bolts? Should I be adding something to the bolts to ensure an airtight fit? Again, this wouldn't be an issue with screw fixings.

No need to add anything since it will be thread against thread. As well, you'll be adding gasket tape to the gasket?

escapemcp wrote: Then I use a pair of beefy pliers (don't know the correct term for them) and hold the tee nut exactly where the holes line up with the teeth:

Pipe wrench.

88h88 wrote:Pipe wrench.

Yeah, that!

Am also looking into getting another amp for safety, as 4 Lab12s on 1 channel of my iNuke is asking for problems! I am buying an 8U rack in a few days, so that I can put all of my kit in one rack and pre-wire it for rapid deployment The amp rack I am looking at is this one:

Although it is 8U, it only has 7U of usable space due to the handle
The rack will consist of:
2U iNuke NU3000DSP
2U iNuke NU3000DSP
1U Power Distro
1U DEQ2496
PLUS a 1U amp for the tops
I also have a 1U size D signal/power/speaker distro panel, but this barely takes up any space behind the panel, so I will probably put this on the back of the amp rack.
I think I am looking at the Synq Digit 1K0, because it has received favourable comments on here. Does anyone else know of any other suitable 1U amps that will drive Otops (and later on, DR250s) please? Finally (and this is the answer I am not looking forward to) is the airflow front to back or back to front on the Synq?

Many thanks as ever

88h88 wrote:

escapemcp wrote: Then I use a pair of beefy pliers (don't know the correct term for them) and hold the tee nut exactly where the holes line up with the teeth:

Pipe wrench.

Pump pliers, Water-pump pliers or Multi-grip pliers.

This below is a pipe wrench

I'm with Harley, Multi's for sure.

Pipe Wrench works, I often hear it called a 'Stilsons' though.

4 T30's yyeeeeeeewwwwww! Nice one!

Titanium Hand wrote:I'm with Harley, Multi's for sure.

Pipe Wrench works, I often hear it called a 'Stilsons' though.

This is why I included a pic... You can call it what you like, but there is no confusion with the image!!

Titanium Hand wrote:4 T30's yyeeeeeeewwwwww! Nice one!

Yyeeeeeewwwwwwwwww indeed! Not quite hifibob territory, but it should make my rig more noisy (and that's the good noisy too )

Harley wrote: Pump pliers, Water-pump pliers or Multi-grip pliers.

This below is a pipe wrench

Multi grip yeah, the other two terms I've not heard used for them. Definitely heard them called a pipe wrench more often than anything else.

Also escape I was just about to jump in about that rack being a 7U and not an 8... I have one similar and I thought I was going insane because I thought I could get more kit in it. I then counted and no, 1U is used up by the retractable handle.

If you are comfortable building Bill's cabinets, a rack box should be child's play. Order some rails and have at it. I wouldn't do anything less than 12U. You get to choose the wheels and handle style and still be money ahead. I'm rollin' about 60U all together with my kit and a big chunk of that I built myself.

88h88 wrote:Also escape I was just about to jump in about that rack being a 7U and not an 8... I have one similar and I thought I was going insane because I thought I could get more kit in it. I then counted and no, 1U is used up by the retractable handle.

Do you still use it?? (I.e. is it for sale )

draehn wrote:If you are comfortable building Bill's cabinets, a rack box should be child's play. Order some rails and have at it. I wouldn't do anything less than 12U. You get to choose the wheels and handle style and still be money ahead. I'm rollin' about 60U all together with my kit and a big chunk of that I built myself.

I thought about this, but the last time I made a flight case (that my CDJs and mixer are in (see above for pic)) it came out to well over £100. With the weight reduction from the plastic case, and the gain that I get in time, I figured to buy rather than build. The difference would probably only be £20 or £30. I'll probably use the time I gain to get going on some DR250s

Harley wrote:

88h88 wrote:

escapemcp wrote: Then I use a pair of beefy pliers (don't know the correct term for them) and hold the tee nut exactly where the holes line up with the teeth:

Pipe wrench.

Pump pliers, Water-pump pliers or Multi-grip pliers.

We call 'em channel lock pliers.

escapemcp wrote:Do you still use it?? (I.e. is it for sale )

I do still use it, yeah. It's all I need size wise for all my kit. 1U of mains distribution, 2U of DEQ/DCX and 4U of amps. I'd love to get cost price on those things, they seem silly expensive for what they are.