HowieZ's T24 build

[Bill Fitzmaurice]

My booth is my back yard. You want to have the cab sit in the sun anyway to cure the Duratex.

[howiez]

Ok, I have one cab pretty much done and I've done some listening. I've placed it on the floor in the garage next to my pair of Titan 48's. I took one Titan offline and connected it's amp to the T24. I used the Dayton Audio phone mic to roughly match the level of one T48 and one T24. I'd run the T48, check levels peaking near 30Hz at 85dB. Then I'd turn it off and match the T24 to it. I did not try to compute voltages or anything fancy since I knew this was kind of apples to oranges anyway. On my BASH300 amp, about 2 notches on the dial higher matched them pretty close. Then I spent a few hours listening to music, one track or passage at a time through the Titan, then turn it off and repeat with the Tuba. I can hear/feel more bass, or deeper bass with the T24, mostly on Dance/Synth stuff. I'm assuming the Titan will have more mid-bass Rock type punch, but I'm not noticing a difference there. Is that it in a nutshell, Titan for live, Tuba for recorded?

So the Titan looks to have a horn length about 1.5' more, just roughly guessing from CAD measurements. Is it the flare rate that is generating more low end, or the length is giving more efficiency? I think you said width is sensitivity, so 24" compared to 18" in my case.

As an aside, I had my son listen, sort of blind. I let him near them, but would not tell him which was on. I played several tracks, one at a time, restart and switch subs, then on to next. He could not tell at first, perhaps due to my track choice. For sure a few times he like the Titan better, and eventually he felt one had a little more 'feel' bass. We also noted there is far more air velocity in the mouth on the Tuba vs the Titan. They are always calm and collected where the Tuba now seems like it's wild. I was thinking home stereo compared to car with an aftermarket sub. I can't wait to finish the pair and hook them up to my PA2 and Crown for some real testing.

Thanks again Bill for great designs, and projects to keep me out of trouble! Or maybe not, now I'm almost sure I need to build a T30 or two... I need to find someone to commission these things or I'll go broke in drivers and ply LOL.

[Bruce Weldy]

Ok, I have one cab pretty much done and I've done some listening. I've placed it on the floor in the garage next to my pair of Titan 48's. I took one Titan offline and connected it's amp to the T24. I used the Dayton Audio phone mic to roughly match the level of one T48 and one T24. I'd run the T48, check levels peaking near 30Hz at 85dB. Then I'd turn it off and match the T24 to it. I did not try to compute voltages or anything fancy since I knew this was kind of apples to oranges anyway. On my BASH300 amp, about 2 notches on the dial higher matched them pretty close. Then I spent a few hours listening to music, one track or passage at a time through the Titan, then turn it off and repeat with the Tuba. I can hear/feel more bass, or deeper bass with the T24, mostly on Dance/Synth stuff. I'm assuming the Titan will have more mid-bass Rock type punch, but I'm not noticing a difference there. Is that it in a nutshell, Titan for live, Tuba for recorded?

So the Titan looks to have a horn length about 1.5' more, just roughly guessing from CAD measurements. Is it the flare rate that is generating more low end, or the length is giving more efficiency? I think you said width is sensitivity, so 24" compared to 18" in my case.

As an aside, I had my son listen, sort of blind. I let him near them, but would not tell him which was on. I played several tracks, one at a time, restart and switch subs, then on to next. He could not tell at first, perhaps due to my track choice. For sure a few times he like the Titan better, and eventually he felt one had a little more 'feel' bass. We also noted there is far more air velocity in the mouth on the Tuba vs the Titan. They are always calm and collected where the Tuba now seems like it's wild. I was thinking home stereo compared to car with an aftermarket sub. I can't wait to finish the pair and hook them up to my PA2 and Crown for some real testing.

Thanks again Bill for great designs, and projects to keep me out of trouble! Or maybe not, now I'm almost sure I need to build a T30 or two... I need to find someone to commission these things or I'll go broke in drivers and ply LOL.

Tubas go lower.

Titans are louder.

[Seth]

"Titan's go louder & Tuba's go Lower" isn't a super accurate catchall phrase. T48's will beat the pant's off a T24 in extension any day of the week... especially since the recommended Highpass for a pair of T24's is 45Hz, where two two T48's is 40hz. As reported, it appears either cab is using the same EQ as the other, I'm pretty sure what Howie is hearing is the difference in each cab's sonic signature or response.

Looking at the graphs below, it does make sense though, that an 18" T24 could start to take on the "sonic signature" of the 16" shown in the graph, with a little kick at the bottom end. Where the 24" T24's response more closely resembles that of the T48.



I'm really happy to hear you are pleased with your results Howie! That's awesome! I can't wait until they get the full dial in!

An important reminder: Howie's T48's are a slight breakaway from the plans. The construction was modified to fit some 18" B52 drivers that PartsExpress had on a blowout sale a few years back. I think these were the ones and it looks as though the specs are a fit, other than the driver diameter. Not sure how well they'd model compared to the green trace above.

[Seth]

Howie, I don't think I remember you saying what driver you ended up going with for the T24's. What drivers are in there?

[howiez]

Looking at the graphs below, it does make sense though, that an 18" T24 could start to take on the "sonic signature" of the 16" shown in the graph, with a little kick at the bottom end. Where the 24" T24's response more closely resembles that of the T48.



An important reminder: Howie's T48's are a slight breakaway from the plans. The construction was modified to fit some 18" B52 drivers that PartsExpress had on a blowout sale a few years back. I think these were the ones and it looks as though the specs are a fit, other than the driver diameter. Not sure how well they'd model compared to the green trace above.

You may be right, that bump, could be a sweet spot in what I'm hearing. Louder (at that freq), not necessarily better. Also worth noting, as you mentioned, I'm using 18's in my Titans, yes Seth, those are the right ones. They are supposedly the ones used in the B52 horn (similar the the popular Cerwin Vega 36x36ish model, but may have less output (due to large cone size, and therefore flex), than the recommended 15's. IIRC, the T/S parameters were within or very close to spec. My Tubas have a Dayton 10 with aluminum cone, pretty much the reason I chose it. I love my 15 with aluminum cone in the the THT. I think it was also a close match to the recommended parameters for a T24. I'll have to get that cutoff and limit set in my PA2 and give them a full listen when cab 1 is complete.

[howiez]

Been a bit, busy with a vacation week and camping on weekends, but cab 1 is finally done.

I've been listening to it a bit while on sawhorses and sanding/finishing. Hoping to break it in more, as I did not give it a full 8 hours of tones as recommended and I normally do. I ran each driver a few hours, and let music drone on them last two weekends I was home, while working in yard. Now the pair is complete, I've stacked them for now, next to my T48's. As expected, I have to turn them up two notches to match T48 output levels. I'm going to listen as is for a few days. Hoping to set the whole rig up in the driveway this weekend for a proper listen and thrash. I can see where I need to set a low pass, for sure there is more low end i'm not used to hearing in the garage with the Titans. Odd bits are rattling more, granted they are a foot or two closer to the back wall of garage, but also 2ft away from sidewall where Titans are parked. I have to say, I do like the low end on newer music, Rihanna and what not. I don't listen to much new stuff, but definitely some punch there. Also some classic rock has kicked a bit more i feel. That could be the Emperors New Clothes effect though LOL. We'll give them both a listen outside this weekend, with limiters set and low pass to get close to apples to apples.

Cab 1 done

[howiez]

I have a v-plating question, so I need to show my progress, or lack thereof lately. I've been fiddling with casters and feet. I don't remember if I ever showed, but I put the Reliable Hardware Company RH-9024BK-A Recessed Tilt Caster on my T-48's that recess into the corner reflector area some people cut off to save wood and add 'normal' casters anyway. I like them, they move my Titans with ease, combined with the built in handles. Then I ended up putting Reliable Hardware Company rubber feet on my Titans for sitting on my garage floor. So I thought I'd do the same on the T24's and buckle them together as Bill shows in the plans. I have my casters in, feet on bottoms, and I'm putting some on side to V-plate. Then I realized my bottom ones are close enough to the front edge that it keeps the cabs about 3/4 of an inch apart at the mouth. Is this an issue? I may just drill new holes 'behind' the corner stacking chevrons ( I won't use to stack LOL, I just like the looks). I put 4 feet on bottom, and now I'm feeling like I only put 2 on the T48's and let the back sit on the wheels. I'll have to dig them out and look.

casters and rear feet

spacers added to clear wheels

the pair with feet and casters

one cab up close

v-plate mockup

[Bruce Weldy]

I put my T24 on 4 casters. I can't see how you can tip those back and use just two casters as short as they are. Are you going to stack them for moving? Maybe I'm not understanding how you are planning to use 'em.

[howiez]

I put my T24 on 4 casters. I can't see how you can tip those back and use just two casters as short as they are. Are you going to stack them for moving? Maybe I'm not understanding how you are planning to use 'em.

Yes I planned the casters for stacked moving. Roll them to truck, tip up and roll other end in!

[Bruce Weldy]

I put my T24 on 4 casters. I can't see how you can tip those back and use just two casters as short as they are. Are you going to stack them for moving? Maybe I'm not understanding how you are planning to use 'em.

Yes I planned the casters for stacked moving. Roll them to truck, tip up and roll other end in!

Sounds like a plan.

[Rich4349]

PRETTY sure Bill has said that the gap will be of negligible importance, but if it bothers you, just move the feet of one both outboard a bit, or move all four frontmost ones back a wee bit for clearance.

They look beautiful!

[Bill Fitzmaurice]

A gap would be a problem if it was a significant portion of a wavelength. The shortest wavelength passed by a sub would is around ten feet.

[Seth]

A gap would be a problem if it was a significant portion of a wavelength. The shortest wavelength passed by a sub would is around ten feet.

Question/clarification please... The lower frequencies which see the most benefit from the use of a V-plate would still benefit, even if the cabs were a foot or two apart and "V-plated"?

[Bill Fitzmaurice]

To some extent, yes, but I wouldn't recommend it. Why would you have to?