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Report on modded/ upgraded La Scala's


solarcarl

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First let me address the tweeter question. I tried the tweeters in both vertical and horizontal orientation and horizontal seemed to carry a wider sweet spot and also with the brackets I made I can angle them up or down as desired so it was the better way to orient them.

The bass port mod; I wish I could say I'd never go back but I thought they detracted from the bottom end. One thing I've come to appreciate about Klipsch folded horn woofers is that low notes sound like faithful representations of the instruments and with cheap speakers all the low details wash out and any lows just end up sounding like"duff,duff". Well some of that fine detailing in the midbass seemed to go away when I put the bass bins under the speakers and my original reason for doing that mod was to get lower and punchier bass and that never emerged with this mod. I also have Vandersteens and at times I like their low end punch but I also hear them make floppy bass sounds lacking detail and find myself missing the La Scalas. I had a sub-woofer that I used to run but couldnt stand what it did to music. A kick drum shouldnt sound like the same kind of rumble you get from a bass string rattling.

I used these plans that someone had posted on this forum earlier and used the bass tubes as recommended which are 4" diameter and 7" long. Actually Parts Express had some that were very close to that size and had flared mouths, part number 260-480. They call the 7 5/8 long x 3 3/4s but the taper of the tube goes from that to 4 1/4 at the mouth and averaged 4". The length came out almost exactly 7". The cabinets were 1/2" MDF. The lumberyard only had that or 1" and I didnt think it would make a huge difference but 3/4" would have been my preference.They were loosly filled with fiberglass batting insulation.

I just didnt find any improvement other than when you were sitting on the couch in front of them you could feel more of the bass hitting your body but they didnt sound any deeper and if anything weaker. If there are some tweeks anyone can recommend, I'd be happy to try them. I did think of cutting the opening where they match the doghouse to allow me to point the ports out the back and see if that helped.

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Now you've done it. You've convinced me to not waste the time or money on this mod.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

My appreciation of the bass produced by La Scalas and Khorns is similar to your own. I'll gladly trade quantity for quality. If it were possible to get more bass extension from La Scalas without losing the quality of what's there originally, that would be great. Alas, there's no free lunch.

Please understand that I love the sound of Cornwalls, but I wouldn't want to sacrifice the tight bass of the La Scalas to get Cornwall-like bass.

To some degree the same holds true for Khorns. Many speakers go lower, but precious few sound as good doing so. Many years ago I used 4 Speakerlab SKhorns in a mobile DJ business. The bass from them when driven by a Dynaco ST-400 was very tight. One person called to book a return engagement and wanted to know if the price quoted included the drummer. She was convinced that there had been a live drummer.

Thanks for the details. I would have done essentially the same and, I expect, reached the same conclusion.

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I'm happy to keep experimenting with that mod but I need some suggestions as to where to go with it. I would guess a lot of the trick is in tuning the ports. Also this could be another case where the computer modelling looks good on paper and just doesnt deliver in real world. Carl

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I'm happy to keep experimenting with that mod but I need some suggestions as to where to go with it. I would guess a lot of the trick is in tuning the ports. Also this could be another case where the computer modelling looks good on paper and just doesnt deliver in real world. Carl

This goes a bit beyond computer modeling. There have been at least three others on here who have done this mod. At least two of them said they would not go back. djk designed this, and I will just have to say I put way more stock in his work and designs that this single bad rap. He said that no one he has shown this mod to is going back.

I would make a box out of 3/4 inch and try straight pvc for the ports. You can get 4 inch inside diameter at Lowe's or HD. It's cheap. Dennis said the 7 inch would be better than the 10 inch length he originally posted. Also, make sure those boxes really are sealed wih the bottom of the LS cabinets.

I will definitely be trying this later this summer.

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Yes you could bet with that. If I were the judge, the La Scala would loose to the Cornscala.

Yes this is just my opinion. I have not heard a ported-horn loaded K33 but I would like to try it with a different cabinet than the La Scala. I think it would sound different than the Cornscala IMO. I will say that I have had a pair of La scalas side by side with my Cornscalas in different positions. The Cornscalas were the winner and I sold the La Scalas. This is probably just my preference in Bass. I know the La Scala is Great...no debate there. I think my Cornscalas are "fast"....not rumbly at all.

jc

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Carl,

If you are ever up for it drag the LaScala's and the ports outside and listen to them that way.

If you still don't like the sound of them you know it is the ports.

If the bass sounds good now it opens up the possibility that your room is making the bass flabby/tuby.

Rooms do that... it can be the vicious circle of extending bass

response deeper... you then potentially excite more room nodes which in

turn can screw up the overall sound quality of the system.

Shawn

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I saved the worst for last. I built some of the bass reflex bins to go under the La Scala's and would have to say that they actually made the bass sound worse. I have A/B'd them a few times and they seem to rob some of the mib-bass and loose whatever punchiness was there. I did notice that you could actually feel the bass on your stomach with the bass ports installed but that wasnt accompanied by any other desireable quality.

Anyone in the Bay Area curious about this mod is welcome to borrow my bass boxes. I may flip them upside down and use them as pedestals to put the speakers up higher as I think there was some value in that.

I wanted to post some pics but I dont see that option. Carl

This is what I kind of thought would be the results of the ported pass mod to a Lascala. I bet the Cornscala gives similar results?

Craig

Craig, from my listening to the Cornscala, I'd describe the bass as equivalent to a Cornwall. It actually is something like a Cornwall with a K400 horn and appropriate crossover... so one does get the smooth HF of a LaScala.

I haven't heard the LaScala ported mod, but I think it would sound different (in contrast to Cornwall bass) because it is still horn loaded.

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While playing music, I would feel how much those 1/2 wall boxes are vibrating. Shawn does bring up a good point about the room nodes on the lower frequencies. I wouldn't mind a design somewhere in between the stock and this mod. Say... only go down to 40Hz, or even 45Hz. My JBLs are only rated to 45 and the bass on them (although not horn loaded, is good and solid (and deep).

This is something Josh and I will try soon I hope, just to get some more input on how they sound.

Bruce

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My gut feeling is that if you've got to have lower bass with the Lascala your better off using the quickest possible subwoofer available. This way you can simply shut the annoying thing off and not break your back reversing the mod[;)]

Craig

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Dean,

"The deeper is goes, the "slower" it sounds."

The deeper it goes the 'slower' the wave is. Not the physical speed of transmission but the time it takes for a wave to complete one cycle.

(Ramble mode on)

That is why the adjective of 'fast' bass is really an oxymoron. A 'fast' driver is simply one that has a higher frequency response then another. A tweeter is much 'faster' then any subwoofer.... which would most prefer to try to reproduce a 30hz wave?

What most mean when they say 'fast' is really non-resonant. In other words that the wave stops when it is supposed too. John Dalquist said decades ago 'fast/tight/punchy' (whatever adjective you want to use) bass has nothing to do with how fast a driver starts... it has to do with how quickly the note ends.

Rooms have resonances in them. They ring at specific frequencies (based on their dimensions) for longer then they should. That ringing clouds details and muddies up the entire frequency range It is literally a note playing overtop of everything else when it shouldn't be there at all. Thats bad.

That is the danger in extending the frequency response of any system. You might now reach down deep enough to excite the room into ringing at one of its modes which can muck up the sound.

A ported system is sort of in effect a tuned resonator which is used to try to extend bass response. Poorly tuned ones will have resonances that are 'too much' and can also muck up the sound.

The trick is when you extend to response of the system in a room and no longer like the sound of the system determining if the problem is in the speaker itself or is a room artifact. That is where taking a speaker outside can help... it removes the room from the listening experience.... and typically a speaker will sound dramatically different in that situation.

A simple RTA most likely won't really show this problem even if measured 1m from the speaker. The problem is in the time domain, not the frequency domain. Basic RTAs (or recording measurements from a SPL meter) are 2D, not 3D.

For example it is very possible (and really very likely) to hear a resonance caused by the room but not happen to be in a place where you get amplitude peaking/nulling from a standing wave. The standing wave peaks/nulls are a symptom of the ringing... not the problem itself. The peak/nulls only happen in a few specific places.... the un-naturally long decay (ringing) effects the entire room excepting the couple of null points.

(Ramble mode off)

Shawn

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Shawn, I am glad you brought this issue up about ring time & resonance.

When I explain it to folks, I use the anaolgy of a cheap wine glass vs a crystal wine glass. The crystal is resonant (or like a narrow band filter) so when you tap it with a knife, it will ring for for seconds: "pinggggggggg.......". However, using a cheap wine glass (broad band and not resonant), when you tap it you get a very short "clink".

The analogy is a good one and can actually start you on the issue/explanation of frequency resolution vs temporal resolution. But that is another story...

Good Luck,

-Tom

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Here's a pic of Rotorhead's scratch built LS with the bass extension in the top. Cool. Hope it works for him. I am assuming the ports have other pieces to attach. They look way too short.

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Neil,

I plan on making a solid back without the port holes. I can then switch

them out to see if there is any diffrence.

The ports in the photo are not finished yet that is why the look short.

I believe I will start around 8" and cut down from there. I have a stock LS

that I will compare the sound Q to. No fance tuning machines just old fashion

ear technology.

S. Lee

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