Klipsch La Scala modifications

[NorthofSixty]

Hi,

I own a pair of early model La Scala Industrial speakers that still sound wonderful but the cabinets have seen better days after many years of use on the road. I am now retiring them to home theatre and stereo duty.

I would like to try a modification to the speaker to smooth out the base response but thought I would pass the idea on for an opinion first.

What I propose to do is remove the bottom plywood cover for the bass driver access and install a 15" passive radiator in its place. In particular I would use the 15" SLAPS radiator from the EarthQuake SuperNova MKVI-15. The La Scala's would be raised off the floor on a base to give the radiator room to work.

The other alternative would be to place the passive radiator in a subwoofer cabinet constructed to match the width x depth of the La Scala. The bottom of the La Scala with the access cover removed would form the top of the subwoofer cabinet.

The first option maintains the original cabinet and volume for the 15" base driver. The second option substanially increases the volume and alters the shape of the bass cabinet.

Has anyone tried something similar? What were the results?

[Bill Cain]

As long as you don't cut the original cabinet, I'd say give it a shot.

You can always reverse the process.

[Marvel]

Has anyone tried something similar? What were the results?

Yes... a ten inch highbox under the LS with two 4" dia., 7" long ports can get you close to flat response to 32Hz. Obviously, it is totally reversible since your LS sits on top of the box. If you don't like it you just remove it.

Bruce

[Marvel]

If you like it, but don't like your cabinets to be so tall, you can do the following:

Enclose the back of the top section that houses the mid horn and tweeter. Open up the top of the doghouse, to give you about the same internal volume as the box underneath. A small amount of acoustic fill goes in either design. If you don't like the second mod after you've lived with it, you can seal back up the top of the doghouse and it still won't be visible from the outside.

[NorthofSixty]

Thanks,

Both great ideas. If the passive radiators do not produce good quality results I'll probably try the first concept to see how they perform. My enclosures are in pretty rough shape so if I like the results I would try building the second concept into new cabinets. The advantage of the second concept is that it does not add any height or, more importantly, weight to the existing cabinets. In fact it would reduce the weight slightly.

[JohnA]

I would like to try a modification to the speaker to smooth out the base response but thought I would pass the idea on for an opinion first.

The bass response of the La Scala is pretty smooth, now. It does have a hump near 200 Hz. You can reduce that by bracing the sides like this:

http://forums.klipsch.com/forums/storage/3/1053246/mocksys1sm.jpg

What I propose to do is remove the bottom plywood cover for the bass driver access and install a 15" passive radiator in its place. In particular I would use the 15" SLAPS radiator from the EarthQuake SuperNova MKVI-15. The La Scala's would be raised off the floor on a base to give the radiator room to work.

The other alternative would be to place the passive radiator in a subwoofer cabinet constructed to match the width x depth of the La Scala. The bottom of the La Scala with the access cover removed would form the top of the subwoofer cabinet.

The first option maintains the original cabinet and volume for the 15" base driver. The second option substanially increases the volume and alters the shape of the bass cabinet.

Has anyone tried something similar? What were the results?

La Scalas do lack low bass. The best use of the EarthQuake passive radiator would be to build an EarthQuake subwoofer and attach it to an arc welder for power.

Your idea won't damage anything, but it doesn't look likely to do any "smoothing". The EarthQuake passive radiators are extraordinarily stiff. It surprises me the subs can go so low. But, the woofer, chamber volume and passive's stiffness all must be matched in order to get good low frequency response. Since the back air chamber volume is relatively fixed, you need to find a passive and woofer that work with that volume.

[Islander]

It's your time and money, but it would be simpler to just add a sub. Even a modified La Scala won't go that low, while a good-quality sub will reach down to 25Hz or lower.

[Marvel]

It's your time and money, but it would be simpler to just add a sub. Even a modified La Scala won't go that low, while a good-quality sub will reach down to 25Hz or lower.

You can't add a sub for, pardon the pun, sub $50. So 30-32Hz so much higher than 25Hz. How long do you think it will take to build the boxes? A Saturday afternoon or a couple of evenings and you can try it. I would rush to try this if I weren't already happy with my LS the way they are. Still, this summer it's going to happen.

[IndyKlipschFan]

Why not just build a K horn bottom box... You have the mids n highs for it..hehehehehe

Sorry, just too easy here..

Add the subs..

[Marvel]

Why not just build a K horn bottom box... You have the mids n highs for it..hehehehehe

Cutting and assembling all those pieces can be a bit daunting, Roger.

Add the subs..

Let's see... cost, placement, just more stuff. I'm a pretty simple guy.

[Bill Cain]

Add me to the group that suggests adding a sub.

K.I.S.S. usually is the best approach.

[Marvel]

I'm sorry, but K.I.S.S. would not be adding more electronics and sepakers. The porting is much more simple.

Once I get my mods done thhis summer, I will be more than happy to arrange to haul them up to Indy so they can be tested. I am sure that canbe worked out. Even without the e.q. put in between the pre and power amp, I think it is worth it.

[Islander]

Once I get my mods done thhis summer, I will be more than happy to arrange to haul them up to Indy so they can be tested. I am sure that canbe worked out. Even without the e.q. put in between the pre and power amp, I think it is worth it.

Good idea! After all, the proof is in the listening.

[Marvel]

Once I get my mods done thhis summer, I will be more than happy to arrange to haul them up to Indy so they can be tested. I am sure that can be worked out. Even without the e.q. put in between the pre and power amp, I think it is worth it.

Good idea! After all, the proof is in the listening.

I'm not trying to give everyone a hard time about this, but I've only heard of ONE person who didn't like this mod.

[sailorcrew]

Hi Marvel,

A couple of questions, if you don't mind, regarding the bass bin addition. Is 9" of internal height the goal? Using 3/4" plywood that would leave the outside 10 1/2" tall, is that ok? From all the threads I've read regarding this, it doesn't seem that any crossover mods are necesary. Is that true? Is adding material (batting) critical and if so, how much, what kind? For the record, I have an older pair of LS courtesy of John Foley and I have updated the tweeters and crossover from Bob, type A. Thanks, David.

[NorthofSixty]

Over 20 years of auditory abuse probably means I won't be able to hear anything below 30Hz anyway. I am really starting to like the concept you have proposed more than my original passive radiator idea.

I normally use white noise and an ADC SoundShaper Mk-III parabolic equalizer to set up the LS for room accoustics. As such, I am not much for subwoofers because I find them too difficult to balance with the mains for audiophile purposes. I only use a sub for home theatre purposes where feeling is as important as hearing the lower frequencies.

I also drive the speakers with a vintage Dynaco Stereo 400 amp which has lots of smooth low end punch. Coupled with the SoundShaper Mk- III I should be able to fine tune the ported design to compensate for any low end rolloff.

thanks again.

[Bill Cain]

I only use a sub for home theatre purposes where feeling is as important as hearing the lower frequencies.

I am extremely comfortable with subs, as they are seamlessly integrated into the systems I use. That said....

This porting idea may be a darn good idea, if it gives the claimed results. I look forward to learning more about it and seeing/hearing the results. I have 4 LSI's that may benefit from such a mod. I really like the illustrations; they make the idea come to life.

[Bill Cain]

I'm not trying to give everyone a hard time about this, but I've only heard of ONE person who didn't like this mod.

Who has actually DONE this mod? What were the results?

[Marvel]

Dizrotus has done this mod, djk came up with it and has done it on more than one system..., Santa Lee built a set from scratch. I know there have been others on here but I can't remember them at the moment.

[philipbarrett]

Who has actually DONE this mod? What were the results?

I did it today, one channel only. Box is a bit crude, needs re-gluing before screwing but I'll fix that tomorrow when I build #2. Nothing there that can't be had at Home Depot, I used MDF which is so easy to work with, plus the sun was shining all afternoon which made for a pleasant build.

Impressions? I'd say subtle is the 1st phrase that comes to mind. Obviously trance music will bring out more of the effect than say folk. It's certainly very listenable too and does not detract from the upper registers in anyway. That being said, if you're looking for subs this is not going to fit the bill.

However, getting the LSs up by 10" puts them in a perfect place for couch listening which may make the mod worth the price of admission in itself.

I did try a Crown DC-150 today to play around with the "Solid State gives more low end than tubes" theory. Those of us with glowing heaters in the listening room will be glad to know that the Crown (known for it's solid low end) failed to produce as much bass as my Pilot SA-260.