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Lab12 Based Bandpass Sub

Printed From: Speakerplans.com
Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=88330
Printed Date: 26 March 2026 at 9:25pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com


Topic: Lab12 Based Bandpass Sub
Posted By: Jebimasta
Subject: Lab12 Based Bandpass Sub
Date Posted: 26 August 2014 at 1:03pm
Hi Folks,

I've got two spare Lab12 drivers kicking around and fancy building something for them.

I'm currently rocking Tony Wilkes f208 + fth12 and so think something to fill in the low end would be nice.

Since a labhorn i've been told would be totally useless as a single and in fact way too big, I was thinking about a bandpass cab that would fill in 30-60Hz ish.

How reliable are the WinISD simulations for 4th/6th order cabs? and is there much more to port design than just checking the air velocity?

I've whipped up something over the bank holiday shown below, any issues I'm not aware of? Or any other suggestions?

Thanks,

Robyn




Replies:
Posted By: djeddie
Date Posted: 26 August 2014 at 10:45pm
IIRC, the Lab12 driver isn't that sensitive, so have a check what the SPL output will be. It might be too low to use anywhere other than home.


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Chas n Dave : it's like Drum and Bass but with beards.             E=mc² ±3dB


Posted By: space-face
Date Posted: 26 August 2014 at 10:49pm
I think winisd is pretty good with simulating BP cabs but it'll never be spot on. Can always make ports longer than needed and trim to size after measuring. As long as the port velocity is fine then you're good to go - just need to make sure that they start well away from any surfaces or the driver which would effectively lengthen the port and lower the tuning.


Posted By: Jebimasta
Date Posted: 26 August 2014 at 11:13pm
Yeah the sensitivity is low, only hitting about 91dB with that tuning. I only ever use this kit for home and house parties anyway, will just be nice to have some use for them.

Plus it's another build under the belt!

Measuring might be a hard, still haven't invested in that gear, I'll just go by my untrained ear for now :P

Thanks!


Posted By: Peter Jan
Date Posted: 27 August 2014 at 12:11am
With those speakers and for occasional home/house parties, I would tune them higher to get some usefull sensitivity where it's more needed for that kind of use.


Posted By: Jebimasta
Date Posted: 27 August 2014 at 8:20am
The FTH12 is good down to about 45-50hz, I would like something to fill in a little below that.

I've actually got a tune I'm thinking of where the FTH12 just can't hit the low note




Posted By: Peter Jan
Date Posted: 27 August 2014 at 11:10am
That kind of "sub" sits higher than you think.
I did some simulations of where I would aim at (two LAB12's in one cab).
You'll see what goes on when you tune higher and specifically to complement FTH12.
It does take a good chunk of extra volume, but those LAB12's are A LOT more capable like that.

Yellow : what I would do
Purple : your simulation
White : ~simulation of an FTH 12 for comparison

Power matched :
http://s78.photobucket.com/user/Peter_Jan/media/Powermatched_zps744cadd9.png.html" rel="nofollow">


Power matched Xmax :
http://s78.photobucket.com/user/Peter_Jan/media/PowermatchedXmax_zps336aea14.png.html" rel="nofollow">


Level matched Xmax :
http://s78.photobucket.com/user/Peter_Jan/media/LevelmatchedXmax_zpsca353517.png.html" rel="nofollow">


Posted By: Jebimasta
Date Posted: 27 August 2014 at 11:27am
I see, the white line is an approximation of the FTH12 response? If I'm going to be pushing the system that makes more sense, is it simmed with 2 drivers?

If not, then I could have a smaller more flexible sub with slightly less output, maybe I'll try both! 
Just seen that post properly. looks like a much better way to go :)

I wonder if I could find anywhere to hide a 314 litre cab... Upholster the top and turn it into a bay window reading seat!


Posted By: Peter Jan
Date Posted: 27 August 2014 at 11:52am
Originally posted by Jebimasta Jebimasta wrote:

I see, the white line is an approximation of the FTH12 response?

Yes, it's a simulation as best as i could match in WinISD

Originally posted by Jebimasta Jebimasta wrote:

If I'm going to be pushing the system that makes more sense, is it simmed with 2 drivers?

2 drivers in one 314 liter internal volume cabinet indeed.

Originally posted by Jebimasta Jebimasta wrote:

If not, then I could have a smaller more flexible sub with slightly less output, maybe I'll try both! 
Just seen that post properly. looks like a much better way to go :)

The LAB12 is not the most sensitive speaker as it is and tuning it low is perfectly possible with it's T/S specs, but you loose big time in sensitivity and run real fast into Xmax.
For strictly home cinema duty it would make perfect sense to do it like that, because SPL needs aren't that high and solid 25-30Hz respons has meaning there.

Originally posted by Jebimasta Jebimasta wrote:

I wonder if I could find anywhere to hide a 314 litre cab... Upholster the top and turn it into a bay window reading seat!

Two seperate ~157 liter single speaker cabs might be more manageable ?


Posted By: Jebimasta
Date Posted: 27 August 2014 at 11:57am
Far more manageable :) Could design them to sit under the FTH12 neatly too :)

Thanks for the advice, I'll have a play tonight.


Posted By: Jebimasta
Date Posted: 07 September 2018 at 6:55pm
I never did get round to that build...

Instead I put one to use in a reflex box, 100l to go with a 5.1 surround system.



Posted By: concept-10
Date Posted: 07 September 2018 at 7:59pm
Nice Smile


Posted By: VECTORDJ
Date Posted: 07 September 2018 at 8:15pm
I agree with the posts from others. Lab 12 in a ported or bandpass box is best for home HiFi. The SPL is way too low. Power in watts is way too low for real PA work. 


Posted By: JonB67
Date Posted: 07 September 2018 at 10:34pm
didn't doller build some art welter double lab 12 boxes on here a while ago?

Edit: thought so!
https://forum.speakerplans.com/arts-dual-lab-12_topic99080.html" rel="nofollow - https://forum.speakerplans.com/arts-dual-lab-12_topic99080.html


Posted By: bitSmasher
Date Posted: 08 September 2018 at 2:07am
What small drivers did you use for those speakers?

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https://www.instagram.com/batteryacidsoundsystem/


Posted By: APW
Date Posted: 08 September 2018 at 10:59am
they look like FaitalPro 3FE22 or 3FE25 drivers.


Posted By: Jebimasta
Date Posted: 08 September 2018 at 11:12am
That's it, faital 3fe25. Decent price for a decent full range driver. 




Posted By: Jebimasta
Date Posted: 08 September 2018 at 11:16am
They look like a beast of a box, lovely build too.

I got a plunge saw recently and that made my build so much easier, the sub was built in an afternoon. 

Tempted to make more but I've run out of space LOL


Posted By: VECTORDJ
Date Posted: 08 September 2018 at 8:54pm
EAW SB2001   This is the sub to copy. Look at the data sheet for the needed EQ.


Posted By: Jebimasta
Date Posted: 08 September 2018 at 9:21pm
Originally posted by VECTORDJ VECTORDJ wrote:

EAW SB2001   This is the sub to copy. Look at the data sheet for the needed EQ.

Dual 21"? I don't see the connection.


Posted By: djeddie
Date Posted: 09 September 2018 at 1:56pm
There was an EAW 2 X 12 horn that used a driver that was similar to the LAB12. Sure it was on the forum somewhere.


-------------
Chas n Dave : it's like Drum and Bass but with beards.             E=mc² ±3dB


Posted By: doller
Date Posted: 20 September 2018 at 11:58am
If I was doing it for home theater I would have copied this guy. Doubt that I could have made them as nice. just outstanding work.    https://www.minhembio.com/MattiasBGD/340709/" rel="nofollow - https://www.minhembio.com/MattiasBGD/340709/


Posted By: Jebimasta
Date Posted: 20 September 2018 at 12:12pm
What a finish he achieved there! I just don't have the skills or patience for that.
Mega ports he's got going on too, makes me wonder about the design process, ports that large for me end up a mile long?! 100l net but 150l sized box to fit the port sort of thing


Posted By: concept-10
Date Posted: 20 September 2018 at 2:40pm
Gorgeous Smile


Posted By: Jebimasta
Date Posted: 20 September 2018 at 3:11pm
Can't wait to have a little workshop space and to put a few grand down into a small CNC router, then I'm sure I'll be churning out stuff like that Wink


Posted By: doller
Date Posted: 21 September 2018 at 10:15am
I can't remember or find the original thread. I think he said he was going down to 25hz. Hence the mega ports. I did kinda copy his bracing when I built those Art's. But just such nice work. He really balances the the look of the cab with the driver. As said many times the lab lacks spl. It is an issue on P.A. That said I still love how those Art's sound. In a small (ish) room they do get where you want them to. Why didn't emmy give it a bit more? I know the Danley story. Maybe it isn't possible with that cone. I have no idear.???? Old crocs..Please.


Posted By: DMorison
Date Posted: 22 September 2018 at 11:02am
Originally posted by doller doller wrote:

As said many times the lab lacks spl. 
<snip> Why didn't emmy give it a bit more? I know the Danley story. Maybe it isn't possible with that cone. I have no idear.???? Old crocs..Please.

Driver power handling is a product of all the design decisions that go into its final specs.
For example, if you give a driver stiffer suspension, it'll be harder to cause over excursion, thus allowing higher power to be applied.
If you give it better cooling, you'll allow more power to be applied etc.

In the case of the LAB12, it's designed to be used in a horn where much of the excursion control comes from the acoustic loading of the horn, so the suspension doesn't provide as much excursion control.

It's also intended to be used in a small sealed chamber, and even with the aluminium access plate, that gives very little cooling.

So - the end result of those design decisions which optimise it for the Lab Horn, is lower nominal power handling.

Remember also the relationship between power handling and SPL - even if there were no power compression or excursion issues, doubling power handling only yields 3dB more volume (all else being equal), so not necessarily much benefit.



Posted By: doller
Date Posted: 22 September 2018 at 11:50am
Thanks mr Morrison. Like I said I do know why the lab is the way it is. In a lab horn the spl is no issue what so ever. But excursion is tightly controlled by the rear chamber. ( I have them ).TBH i find that 800 to 1000w is plenty for a Lab horn. It will take more but why bother, expensive error. for 3db. They will run all day everyday at that. Tried and tested. In a reflex box I would say that spl is. Great for home theater however.
I really like the lab drivers they give very clean bass. Shame it seems like a one box speaker so few plans around for other options. No bfm replys please.



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