Klipsch K-43 Dual Chamber MWM Woofers

[nascarguy301]

I have four of these 15's, and i want to get rid of the two dual chamber mwm's because they are too big. They were being used in a skating rink (about 20,000 Sq. Ft.) I want to build four seperate boxes for each of the woofers to be used as "subs" (Under 100 Hz). The only issue i have is that i have no clue what the volume for my boxes should be, or how to build a box that can effectively disperse the low frequencies across the rink, while remaining LOUD. The only thing that threw me off was how i can build a box for them, when they were designed to run in those MWM's, which are unlike any other box ive seen. Any input would be appreciated.

[Frzninvt]

There is really not enough Xmax or excursion on those woofers for them to be used effectively as subwoofers. They are designed to perform optimumly in the horn loaded enclosure where the driver is loaded and does not need massive excursions to get very loud. Better off to sell them and purchase true subwoofer drivers that are capable of greater Xmax's.

You can try it but don't expect much under 50hz you are going to have really large midbass speaker enclosures with tremendous output.

[nascarguy301]

Ive heard these under 50Hz and with the ElectroVoice DC-one processor boosting those lower frequencies, its nothing to laugh at. Of course, thats with them in the MWM's, so it would probably change on the lower end. If you could help me come up with a box design, that would be great, its gonna be tuned low anyways

[Guest " "]

if the k-43's are the stamped metal frame versions , they will fit inside LaScala cabinets. The LF sections of LaScala's are 2ft by 2ft by 2ft. In lascala cabs you will have loud, but not low. LaScala's drop off between 70hz and 50 hz.

if you have cast frame k-43's, you will need to shave off about 1/4 of an inch at the 3 and 9 o clock position to get them in LaScala cabs. mounting holes being 2, 4, 8 and 10 o clock position,

where are you located and what kind of MWM's do you have?

[formica]

There is really not enough Xmax or excursion on those woofers for them to be used effectively as subwoofers. They are designed to perform optimumly in the horn loaded enclosure where the driver is loaded and does not need massive excursions to get very loud.

If you are looking to build a conventional subwoofer out of those, I unfortunately agree with Frzinvt... as they were designed more as mid bass drivers, even though they do go "relatively" low in their horn loaded cabinet. Do you have the T/S parameters handy? You can plug those into a freeware box design program like WinISD which will give you the optimal box size and expected bass extension:

http://www.linearteam.dk/

I too am feeling you could sell the whole MWM as a unit, and pickup some nicer subwoofer drivers with the $...

ROb

[mustang guy]

I agree with everyone above. These are woofers. You need subwoofers for what you are planning. If you could make a LaScala or Belle style base in a woodshop, you would have a darn nice woofer.

[djk]

LaScala with K43

Vented LaScala

[nascarguy301]

These were used in a Skatingrink (Texas Skatium) for the last 30 years. They were reconed, and now, the owner want them to be used as subs to provide a louder lower end.They have WOOFERS covered. They have 26 JBL 15's in the ceiling which are just as old. But the guy wanting me to build an enclosure for these, wans them each in seperate boxes.

[djk]

So build four boxes as above and run them as a block of four.

Should have no problem producing 140dB (peak) at 1M down to 40hz or so.

[nascarguy301]

He wants them spread out. As long as this is a good design, i will use it.

[nascarguy301]

Also, aside from the Box dimensions you gave me, im good. Im not sure exactly what your getting at with the La Scala sketch. How exactly is this supposed to look? Sorry for the bother, but when your workiing with Klipsch, it's gotta be perfect

[mark1101]

You would be better off just getting some subs. You are not going to extract K-43s from MWM cabinets and make them work in a subwoofer. It's the wrong driver to use. They were designed specifically for the application they are used in.

Forget this project, as it is doomed already. Just go buys some used subwoofers.........and relax and have a beer.

Check out the PRO section of this forum. 684 subs would work well.

[nascarguy301]

Would the 684s be LOUD in 20,000 Sq. Ft.?

[mark1101]

The 684 is a logical replacement for an MWM in a more standard size box, but it is also considered a sub. It plays higher than an MWM cabinet and does play lower. It has dual 18" drivers that were designed and approved for THX performance as a sub.

I have heard them many times and they destroy an MWM in output.

In fact, I will own 2 of them this Sunday to compliment the MCM system you see in my avatar........to be used as subs below 50Hz.........but they can also be used up to around 2K.

Just a suggestion. Trying to build subs around old-time Klipsch woofer drivers is futile. Just buy subs.

Lascalas will disappoint big time after owning MWMs. They have far less bass output.

[formica]

He wants them spread out. As long as this is a good design, i will use it.

Djk recommend running four tapped horns as a block because their SPL will be additive. If you ran them spread apart, you run the risk of most probably having cancellations (common at those frequencies) due to room acoustics, and a lower overall spl.

The LaScala comments refer to the Klipsch Lascala box (plans are available elsewhere on here) ... a pretty simple build and is one of the speakers that used the K43... efficient, BUT it will not go very low (less than the MWM) as shown on the graphs.

As mentioned, buying a true Subwoofer or subwoofer drivers will give you better low frequency performance.
ROb

[djk]

The design shown is for a tapped horn type speaker.

If you don't run it in a block of four, don't bother, it won't play loud enough (that applies to other subs too).

The LaScala data was shown for reference only, just to show how much better the tapped horn does with the same driver.

This gives you and idea what happens if you run one, two, or four in a block (all with one watt in)