This weekends LaScala cab upgrade project - Cornwall style bass bin attachment

[Guest " "]

I'm on my way to HD to buy wood for my weekend project.

I want to put a Cornwall stye bass bin on the bottom of my LaScala's.

I have a few choices.

a.) Use the same volume for the attached bass bin as the cornwall. Put a second woofer in the attached bass bin facing the inside of the original LaScala dog house. Pro's are converting the config to push-pull. Cons are increasing the height of the LaScala by approx 1' 9". Impedance is not an issue, I have 4 speakerlab K-horn woofers that are 8 ohms each.

b.) Start out with a volume equal to the cornwall cab volume but reduce the attached bass bin by the volume of the original dog house. Do not use a second woofer. Pro's, height increase is only approx 1' 3". Con's, loose the opportunity to do push-pull.

c.) A variation of a.) or b.) not readily apparent due to either the interaction of the two woofer enclosures under a push-pull version a.) or the horn loading of the woofer in senerio b.) which introduces a significant variation of a.) or b.)

If anyone has some input on this, or another variation...would be intrested in hearing it. My personal preference is version a.)

[Guest " "]

I decided to go with adding 4 cubic ft, remove the lower dog house access panel, and just extend the existing woofers internal volume, while adding a cornwall type vent.

Mian consideration was just curb appeal. making the LaScala's an additional ft high is pretty painless on the eyes.

Here we have a pair in clamp straps anlong with 2 inch aluminum angle stock to help square the joints. The joints were check with a corner square and were good to go.

[Guest " "]

Main joints done. Next will be the bracing where the upper and lower panels attach.

[Guest " "]

I also decided in oing ahead with cutting out circles for a second woofer in the event I want to try a push pull configuration.

[BEC]

Hey, I have seen my dad build that design before we had electricity and running water back here in the hills of Arkansas.

[klipschaholik]

Yeah, one of them fancy two holers with the vents to let the flies out so's you don't get bit!

[Coytee]

Fritzie... my eyes keep going back to your floor... I think it looks nice and I like the diagonal layout of it.

[]

Ok, back to your pictures now...

[jwc]

speakf.

Is there a way you can RTA before and after the mod?

[Guest " "]

Hey, I have seen my dad build that design before we had electricity and running water back here in the hills of Arkansas.

ah, the secret to Cornwall Bass, it's all in the gas.

[Guest " "]

Fritzie... my eyes keep going back to your floor... I think it looks nice and I like the diagonal layout of it.

[]

Ok, back to your pictures now...

The diagonal pattern ends on a diagnonal placed full height gas fireplace.

The hallway to the room has a V-cut pattern that runs about 10 ft.

[Guest " "]

Yeah, one of them fancy two holers with the vents to let the flies out so's you don't get bit!

Well then, if the sound does not make it, I'll put up the bins on ebay as a portable country out house. 4 cubic ft of capacity should be good for a decent sized trip.

[Guest " "]

speakf.

Is there a way you can RTA before and after the mod?

Unless there is a short cut way of doing this thru a default file or something probally not.

I down loaded a version of RTA a while back and it did not seem too intuative.

I have a decent mike with a funky nozzle on it designed for room tuning, but my reciever automaticaly does the corrections, using the mic, theres no capture feature on the reciever. The mic can plug into a standard computer mic input .

If there is a web site that has a short pitch on how to spell RTA with success, I'm willing to give it a try.

I have a framing project going on this week that is going to require most of my attention, but can duck out of it for short spells.

[Rockets]

What's the status on this project??

Thanks

[Guest " "]

Cabs are done, but not attached to the LaScala yet.

JC raised a good action item for me to ponder which was to do some before and after measurements.

The only room suitable for before and after measurements is presently under construction.

I remain anxious to try them...but I do not want to let crappy room dynamics get in the way.

[Marvel]

So these go in a different direction than the djk mods? You have made a larger cabinet volume and tuned them differently. They owould only have to be about ten inches high to do Dennis' mod, even if you used a slot port of some kind. The basic concept is the same.

Bruce

[Guest " "]

So these go in a different direction than the djk mods? You have made a larger cabinet volume and tuned them differently. They owould only have to be about ten inches high to do Dennis' mod, even if you used a slot port of some kind. The basic concept is the same.

Bruce

Aside from the cornwall slot and shelf, I addition, I have a second motor board for a second woofer.....going to convert the dog house to push pull.

The impedance issue will be over come by using 8 ohm versions of the emminance drivers...2 of them in parallel would put me bach to 4 ohms. Like the ones used by speakerlab. I have four in my possession.

The size of the box was curb appeal driven. So I am hoping for an improvement, but don't expect it to be optimal. I did not want 6ft high LaScala's.

[Rockets]

I've got an ignorant question. I've read little tidbits here and there about the K-48, but never any spec's, or if it'll dig deeper when ported. Hearing you state you may wish to experiment with dual parallel 8 ohm woofers made me wonder. Do you know the spec's on the K-48? If you do...would the K-48 be a candidate for such a ported experiment? Not that you have any... I'm just curious.......

[Guest " "]

K-48 does not dig deeper. Of the three, k-33, k-43, and k-48, the k-33 digs the deepest, while the k-48 has the highest power handling.

The spec's of the k-48 has been posted, it is not as good as a woofer for the LaScala as the K-43 or K-33, unless you need a high output PA config, then I would say use a k-48.

[DrWho]

I believe the K-48 is the woofer from the Chorus and a lot of the pro cabs. It was designed for ported alignments and is not related to the K33 or K43 which are both designed for horn use.

Btw, you can't go push pull on the lascala because it throws off the compliance of the rear chamber. In fact, DJK's version of the ported mod was carefully crafted such that the larger cabinet + port presented the same "acoustical suspension" as the stock chamber. This ensured that the horn continued to work as intended. I'm not sure what effect increasing the rear chamber volume might have, but I know it's an integral part of horn design (I believe Dana refers to it as reactance annulling).

[Guest " "]

can't believe it's been 5 years...finally finished it....

http://community.klipsch.com/forums/p/147909/1530147.aspx#1530147