Tuba 60 - 20" version?

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space141
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Tuba 60 - 20" version?

#1 Post by space141 »

Hello everyone,

I have now purchased two eminence lab 12c 500w 4ohm speakers and am eager to get going with the build now.

Having been moving hefty speakers around for a while now I am leaning towards the slim version of the Tuba 60.

There seems to be however two versions of this - the 15" wide or 20" wide version as mentioned here:

viewtopic.php?t=11124

I belive that the double loaded Tuba 60 is 30" x 30" wide at the mouth so the "slim" version is evidently the 15" x 30" version but then would that mean that the 20" version gives you slightly more output whilst being 2/3 of the width...?

I am keen to save my back and build several slim versions rather than double versions at this point - just intrigued by the mention of a 20" tuba and whether anyone can shed light on this.

Many thanks,

Thomas (Glasgow, UK.)

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Bill Fitzmaurice
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Re: Tuba 60 - 20" version?

#2 Post by Bill Fitzmaurice »

Th 15"and 20" are but two of the possibilities with the 1x12 T60, which may be built in any width between 15 and 20 inches.

Grant Bunter
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Re: Tuba 60 - 20" version?

#3 Post by Grant Bunter »

Do your plans say the lab 12C is a recommended driver?
IIRC, the lab 12c TS parameters are outside those listed in the plans, and you can only run 1 cab per amp channel if that amp is stable to 4 ohms.

I’m pretty sure the recommended driver is the lab12 which has the right TS parameters and a nominal impedance of 6 ohms...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

space141
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Joined: Sat Jun 13, 2020 12:17 pm

Re: Tuba 60 - 20" version?

#4 Post by space141 »

Thanks for all the swift replies - this forum is fantastic!

RE Grant Bunter: I did not realise that the parameters for the 12c would be any different than the lab12. Does this mean that it will not be suitable for this cabinet build or just that it might not be as efficient..?

I was intending these to go under our vintage fane 15" long throw w-bins (see attached image.)

Image

It would be great if we could make the dimensions of two Tuba 60 match the width of one of these which are 44" wide.

So, would it be possible to build it 22" wide so that we can put two together underneath or would the orientation of that mean that the mouths weren't coupled in the most efficient manner?

Sorry for all the questions, guess that's what this forum is for.

Thanks in advance!

Thomas.

Grant Bunter
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Re: Tuba 60 - 20" version?

#5 Post by Grant Bunter »

It's been years since I've compared the lab12 and the lab 12C.
It's something you should do though, the T60 design is based on the TS specs.
So it's not just possible efficiency, but performance and hence results from your build that may be at stake.

Errrr, now you're throwing in a fane cab as well, I think you need to go back to the start and explain everything from the very beginning.
Tell us what your plans are and why you're thinking that.
And also what you're trying to achieve, what you're going to power all this with, and what you're going to use to protect and limit as per the plans...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Bill Fitzmaurice
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Re: Tuba 60 - 20" version?

#6 Post by Bill Fitzmaurice »

Grant, you forgot about his wanting to put the subs below the mains, which indicates he probably hasn't read this: viewtopic.php?f=10&t=398

space141
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Re: Tuba 60 - 20" version?

#7 Post by space141 »

Thank you both for your replies and the link to the subwoofer placement and stack page.

You are right, I hadn't read that page but then I wasn't aware that this would be such an issue as this isn't mentioned specifically on the Tuba 60 page.

This shouldn't be a problem however as am happy to place them wherever in the room/ or angled with the floor outside if that is what will work best of course.

I am slightly concerned however about the fact that I have already bought the 12c (500w) version which I thought might give me a bit more output with fewer cabs - we typically do events for audiences between 500 - 1000 people. So, according to the figures on the page I would be looking to build between 6-8 of the slim version tuba 60 to cover that...?

Another thing making me rethink whether Tuba 60 is even a good option is what was written in the article you linked to titled Using Tubas with other subs:

"Mixing horn subs with direct radiators is a recipe for disaster. The response of the two formats is so different that it's impossible to EQ either one of them properly, while differing phase can easily lead to blown drivers. Never mix even different models of subs, including Titans or Tubas, let alone different formats."

Maybe I hadn't done enough research prior to deciding that I would build some Tuba 60's but I believe that this information is not made very clear on the page Tuba 60 home page.

Is this going to be a real problem having these playing alongside my Fane long-throw w-bins.

A few details and specs of our system:

We have four CREST CA12 amps: 1200w/channel into 4ohms

planning on running 4 Tuba 60 'slim verion' @ 30-90Hz.

then 4 Fane W-bins loaded with FANE 15XB 800W RMS speakers running off two CREST CA12 - 90-200Hz.

4 mt121 horns loaded with B&C 12PE32 250W - running off CREST CA9 - 200Hz.- 1kHz.

then 2' compression drivers and JBL 2402 bullet tweeters. 2" compression drivers 1kHz-7kHz, Bullet tweeters 7kHz.- 20kHz.

Many thanks in advance for all your help and advice,

Thomas.

Grant Bunter
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Re: Tuba 60 - 20" version?

#8 Post by Grant Bunter »

Hi Thomas,
Double 4 ways should be extinct, only because they are a mess of work for no benefit.
I wouldn’t build T60’s as slims.
Then again, I wouldn’t use kick bins either.
I would also build dedicated top boxes instead.
You didn’t mention limiting.
At least you’re not trying to run different cabs in the same band passes.

To be fair, much of what is in the subwoofer sticky should be general knowledge. It doesn’t only apply to Bill’s designs, but all designs from any brand.

So, I take it the fanes are your current subs. How are they lacking? Do you just need more of them?
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Bill Fitzmaurice
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Re: Tuba 60 - 20" version?

#9 Post by Bill Fitzmaurice »

Grant is right, running separate kick bins from 90-200Hz is a waste of cartage and amp channels. So is running compression horns for the mids and bullet tweeters for the highs. All you need is subs and two way mains. A well designed system would allow you to reduce your load in by at least 30%. Then you could build T60s in the optimum size for maximum output.
Maybe I hadn't done enough research prior to deciding that I would build some Tuba 60's but I believe that this information is not made very clear on the page Tuba 60 home page.
That's why it says on the site home page Chat with other builders on the Forum. You can benefit from the experience of thousands of builders/owners to decide which speakers are right for you, and how to build them. We highly recommend you join the Forum and be sure of which plans best suit your needs before ordering.

The LAB C are OK, but you won't get a single dB more out of them than with the standard LAB 12. Maximum output is limited by the driver xmax, not the voice coil thermal rating. Xmax for the two versions is the same.

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Seth
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Re: Tuba 60 - 20" version?

#10 Post by Seth »

Bill Fitzmaurice wrote: Sat Aug 29, 2020 8:08 am The LAB C are OK, but you won't get a single dB more out of them than with the standard LAB 12. Maximum output is limited by the driver xmax, not the voice coil thermal rating. Xmax for the two versions is the same.
I suppose a possible benefit could be getting the same output, but requiring less voltage (smaller amp) to do so... perhaps?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Bill Fitzmaurice
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Re: Tuba 60 - 20" version?

#11 Post by Bill Fitzmaurice »

The difference between 4 and 6 ohms isn't that much. If I had to use LAB 12C it would be in 2x12 T60 wired series for 8 ohms. That way you could run a pair off one amp channel.

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