Dual Loaded Table Tuba by a Teenager

[bassmonster]

Hello Everyone!

After many months of waiting and contemplation, I decided on a dual loaded TT for car audio. It won't be allowed in my car for about a year after it's built, but I understand that so I will use it in my room for the time being. I asked for all the parts for Christmas (Merry Christmas by the way) and I got them! Two JBL GTO804 drivers, a BASH 300 amp, TT plans, and all the accessories needed to build it.

Here's my first attempt to post pictures on this forum, I hope it works. Pics are blurry because I set the camera in low quality mode to keep the image small (?) I'm currently breaking in the drivers, and I made sure the pole vent is not covered or smothered by anything. I also need to make a box for the Bash, should I integrate a cooling fan in there? It is semi-warm while breaking in.



Edit: BTW, you can see my old 8" ported subwoofer in the center of the picture.

2nd Edit: I am building it 24" wide, 23" internals.

[88h88]

Merry chuffing Christmas! The amp will be hot as it's piping through a solid signal rather than busting out peaks every now and again, I wouldn't worry about it getting too hot on regular music duties.

Nice haul. Get building already!

No I have not been drinking all day.

[bassmonster]

The amp will be hot as it's piping through a solid signal rather than busting out peaks every now and again, I wouldn't worry about it getting too hot on regular music duties.

Whew, the amp was getting warm and with all the new stuff I got paranoid I was doing something wrong so I propped it up and have a fan blowing on it. So should I just build the amp box without a fan and just put vents in it?

As for burn-in, the GTOs are wired to 8 ohms because 2 ohms would be unsafe for the amp. I generated a 20hz tone for 8 hours in Audacity and have been feeding them around 10-15 volts (total, not each). Just increased to around 20v after reading the plans (10v to each). Getting about 3/4 inches to 1 inch of excursion.
I won't be able to start building until January, I have a small trip I'm going on Tuesday and I don't want to go out and buy plywood then have it warp in a week.

Okay, just finished completely reading the plans. First impressions: Very thorough. Lots of diagrams. Explains things fully in detail. It is written in a style that assumes complete understanding and "intellectual dominance", if you will, of the subject by the author, which boosts confidence in even the most unskilled woodworkers (me). Thank you Mr. Fitzmaurice for the outstanding plans.

[Gregory East]

Steady on there young one. You're supposed to be breaking it in, not breaking it. Xmax 11.5mm x2 is less than an inch.

[Gregory East]

As it loosens up you might find it travels further on same volts.

[Drey Chennells]

Steady on there young one. You're supposed to be breaking it in, not breaking it. Xmax 11.5mm x2 is less than an inch.

Right, be careful, the drivers are vulnerable here.
Many take decades to find a resource like this one in their field, most never do. The fact that you're about to build a top shelf unit like this so early in the game is a huge advantage for you.

[Tom Smit]

The amp will be hot as it's piping through a solid signal rather than busting out peaks every now and again, I wouldn't worry about it getting too hot on regular music duties.

Whew, the amp was getting warm and with all the new stuff I got paranoid I was doing something wrong so I propped it up and have a fan blowing on it. So should I just build the amp box without a fan and just put vents in it?

Just vents will be fine. Recently I had an amp that I was running 31hz through to feed a pair of TLAHs, and the amp was getting noticeably warm. However, when I played music at the same volume setting, the amp was barely warm.

Just increased to around 20v after reading the plans (10v to each). Getting about 3/4 inches to 1 inch of excursion.

Listen to the drivers carefully. As one turns up the volume, there will be a point that the drivers become noisy as it were. Roll off the volume a touch at this point.

[doncolga]

Steady on there young one. You're supposed to be breaking it in, not breaking it. Xmax 11.5mm x2 is less than an inch.

Many take decades to find a resource like this one in their field, most never do.

+1000

[bassmonster]

Thanks for the break-in advice everyone. Before everyone replied and before I went to a dinner party, I became worried about the noise of the drivers and their vibration and lowered the voltage to about 7 or 8 volts apiece. This kept them silent and they didn't vibrate across the wood pallet they were sitting on either. Although in the plans 10 volts is recommended.

[ncgrove]

Please stop with the incessant pipe dreams and actually do something. Your dreams of rendering others as well as yourself deaf are getting rather old and tiresome.

[Gregory East]

I won't be able to start building until January,

Patience is a virtue. I'd call breaking in drivers "progress", bring it on. I want to hear how pissed off the olds get after being duped into buying a couple of 8" drivers for Xmas. I bet nobody told them about horn loading and 110dB at 30 Hz, did they?

[88h88]

Please stop with the incessant pipe dreams and actually do something. Your dreams of rendering others as well as yourself deaf are getting rather old and tiresome.

Yo it's the Grinch! Relax, he's getting underway now. If you don't like his enthusiasm then don't read his posts, I personally thinks it's great he's so excited about such a project and now has most of the kit to get it done.

[bassmonster]

I want to hear how pissed off the olds get after being duped into buying a couple of 8" drivers for Xmas. I bet nobody told them about horn loading and 110dB at 30 Hz, did they?

I told them about the horn loading and they were dubious, but I don't think they did any research.

[bassmonster]

Heading out of town for a couple of days, will be back Saturday and will get plywood and start my build then.

[subharmonic]

Please stop with the incessant pipe dreams and actually do something. Your dreams of rendering others as well as yourself deaf are getting rather old and tiresome.

Yo it's the Grinch! Relax,

NcGrove you get the double grinch.