I just finished my first BF design, a tuba 24. The plans were very easy to follow. Building material was 1/2'' 9 ply baltic birch. Baltic birch is a huge step up from the crap from Home Depot. Everything went suprisingly smooth for a first time build. Since this is one of many projects on my list of things to do for winter break, (including a second T24) my dad and I working together were able to get this first tuba to a state of functionality (just working, no finishes or handles yet) in about 10 hours.
For our second T24, I will do 2 things differently:
1. Use a different kind of glue. Although the PL construction adhesive recommended in the plans is cheap and easy to dispense from a caulking gun, I find its texture is kind of greasy. Unless forced upon a panel through the gun, it dosent really want to stick to wood. When using clamps to align panels with glue on them before adding screws, the glue acted more like a lubricant and made the panels walk all over the place when varying compressions were put in the clamps. I also found that the PL dosent really expand when it cures. I think the only reason I have an airtight seal (at least it think it is) is because I used really thick beads of glue everywhere. I prefer to work with Elmers Probond Polyurethane Glue. It is more expensive, but really expands to fill gaps. Note: if you get this stuff on your hands, it will not wash off! You literally have to wait til it wears away.
2. Be more careful with T-nuts! I ordered 4 pairs of the parts express #260-776 t-nut mounting kits. The first time I test mounted the driver, the t-nuts were not completely straight, and not perfectly aligned with the driver mounting holes, so the bolts went in and just crossthreaded. When we put the driver in the cab to mount, one t-nut was still off, so we had to make a makeshift tap to fix the threads. Make sure your t-nuts are straight-on for all the driver mount holes. I think part of the problem is that the threads on the 10-32's are too fine. Need something more hefty.
Listening Impressions:
I brought the T24 inside because its raining outside and placed it in the corner of my bedroom.
Sounds great! The first thing I notice is the high efficiency. The room corner loading is probably helping a lot---this sub is sounding big, loud, and clean with just a few watts! It is hard to make any definitive comments for now---listening to music with it right now, and cant wait to put some bass guitar or kickdrum through it. This sub seems to posess what I like most about horns; the quick, punchy response. Where my 5 cu. ft vented box home theatre sub lags behind, the T24 seems to keep with the beat.
Pics and more on the second T24 to come later!
Tuba 24 done!
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Bill Fitzmaurice
- Site Admin
- Posts: 28916
- Joined: Tue May 02, 2006 5:59 pm
Re: Tuba 24 done!
PL makes a number of formulations. PL Premium expands at least 3:1, so you had the wrong one.Daniel wrote: 1. Use a different kind of glue. Although the PL construction adhesive recommended in the plans is cheap and easy to dispense from a caulking gun, I find its texture is kind of greasy. Unless forced upon a panel through the gun, it dosent really want to stick to wood. When using clamps to align panels with glue on them before adding screws, the glue acted more like a lubricant and made the panels walk all over the place when varying compressions were put in the clamps. I also found that the PL dosent really expand when it cures.
second t24 done + pics
Pic of the 2nd t24 almost finished:
http://www.frappr.com/fitzmaurice/photos/3510980
Pic of the 1st t24 corner loaded in my messy disaster of a bedroom:
http://www.frappr.com/fitzmaurice/photos/3511133
After listening to my 1st t24 and knowing that 2 horns is better than 1, I quickly went on to finish my second t24. The first word out of my mouth when listening to 2 t24's corner loaded in my bedroom was "WHOA!". The sound is huge, clean, and deep. Definetely some of the best bass I've ever heard. When hooked up to my dad's bass guitar with a 50 watt amp, everything in the room just shook and buzzed like crazy with the gain turned up to 1/2.
Still havent had a chance to take these puppies outside to play with my midbass horns. Since I believe one's opinions of a speakers sound can change over time, and since I have not had a chance to make a careful listening setup for a/b comparisons, etc., I will make another post later with more detailed listening impressions
http://www.frappr.com/fitzmaurice/photos/3510980
Pic of the 1st t24 corner loaded in my messy disaster of a bedroom:
http://www.frappr.com/fitzmaurice/photos/3511133
After listening to my 1st t24 and knowing that 2 horns is better than 1, I quickly went on to finish my second t24. The first word out of my mouth when listening to 2 t24's corner loaded in my bedroom was "WHOA!". The sound is huge, clean, and deep. Definetely some of the best bass I've ever heard. When hooked up to my dad's bass guitar with a 50 watt amp, everything in the room just shook and buzzed like crazy with the gain turned up to 1/2.
Still havent had a chance to take these puppies outside to play with my midbass horns. Since I believe one's opinions of a speakers sound can change over time, and since I have not had a chance to make a careful listening setup for a/b comparisons, etc., I will make another post later with more detailed listening impressions