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Tizman

Extending La Scala bass bin

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Hi All. 

I did a search for this but didn't find any information, so here I go.  Has anyone tried to make the La Scala bass bin longer/larger by extending the existing horn mouth?  My understanding is that the La Scala is effectively horn loaded to around 100HZ.  If the horn were made longer by extending the mouth outward, would it be possible to lower the frequency to which the La Scala bin would be horn loaded?  I'm not sure what this could look like, or should look like.  Would it be enough to extend the top, bottom and sides outward?  Should the extension flare out on the sides?  If so, what would be the correct angle?  What should you do with the front point of the doghouse?  Extend it out to the new opening, or leave it as is?  Your thoughts, opinions and advice on this are much appreciated.

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Perhaps something more like the picture below?  After you realize that simply extending the LS mouth would be too unwieldy and intrusive into your listening room, and probably wouldn't be very effective in the lowest octave of performance, the picture below might make a lot more sense, adding one more fold to the horn so that it can pick up boundary gain from the room itself:

 

nolid-finalflare-2.jpg

 

Here's a Hornresp model and expansion profile that Greg B. (Edgar) did for the La Scala in 2009, showing the very rapid final expansion of the final horn segment.  This is important if you were only considering extending the horn mouth:

 

New LaScala.png

 

This is the reason why the internal fold in the Jubilee bass bin expansion (pictured at top) is folded back closer to the dog house, so that the next-to-last and last folds expand more uniformly. 

 

Chris

 

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You could also extend the horn throat into the doghouse, that would also extend the length.

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I guess the point is that if you're trying to get lower in-room cutoff of the bass bin by extending the path length of the horn, you need to double the path length in order to gain one more octave lower in response at cutoff...or you can use the room's boundaries more effectively by placing the La Scalas nearer the room corners and using appropriate levels of midrange absorption panels/squares on the adjacent side walls to the midrange and bass bin horn mouths to absorb the early midrange reflections (like is discussed in the corner horn imaging FAQ).  Pulling the La Scalas out into the room loses about 1 octave of bass extension, something that you can get for free with no modifications required to anything.

 

IMG_0208.JPG

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Tizman,

 

Pretty much yes to all, but as Chris demonstrated, the flare added to the front would be large and unwieldy.  A better option would be to face the bass bin into a corner you build resembling the last path of the K-horn Jubilee, with a V that lines up with the point of the dog house.  Each side should expand exponentially from half the area of the La Scala's mouth. 

 

An easy test would be to face the bass bin into a corner with maybe 12" from the side of the mouth to wall.  It's  imperfect because the corner goes away from the dog house, but should give you an impression of its effect. 

 

Folks say you can buy a Jubilee for less than a Klipschorn (add your own xover and amps). 

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11 hours ago, Chris A said:

 

 

nolid-finalflare-2.jpg

 

 

Nice pic.  Havent seen it for a long time.

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13 hours ago, Tizman said:

Hi All. 

I did a search for this but didn't find any information, so here I go.  Has anyone tried to make the La Scala bass bin longer/larger

Actually , when you see a Jubilee , there are 2 ,  12 inch woofer -, but the cab is wider -    One could make a scala speaker with a  wider dog house  for housing an 18 inches  woofer-    it would have to be about 5 inches wider -

-another way would be to make a longer bass bin  to  house either 2 -  15 inches woofers or 2 -12 inches woofers -this would be keeping with the original design of the speaker but wider or longer - with no need for a wider horn mouth -

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Thanks for all the replies.  I have some more interesting things to think about.  I was considering the Jubilee, but had heard that the dual mouths created issues with response.  These issues are avoided by the La Scala because of the joining of the two mouths, or so I read somewhere in these forums.  The idea of extending the horn loaded bass by adding to an existing cabinet is very attractive, as it is far less work than building an entirely new cabinet.  That said, the Beck California is something that I have been very interested in for a long time.  The California appears to be a relatively straightforward build, with one mouth and a horn loaded lower frequency that is lower than a jubilee bass bin.  Moray James has been suggesting it in these forums for some time.          

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A lascala with a longer horn? Try a pair of mwm bins. 

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4 hours ago, Skelt said:

A lascala with a longer horn? Try a pair of mwm bins. 

 

Two times the drivers of the MWM bins doesn't hurt either. As in performance cars/engines, "there is no replacement for displacement". Even the MWM bins are only rated down to 35 hz, -10db output. 

 

So its not about a longer horn, but 2 times the driver radiating surface area per unit, and power handling.

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There are mwm single driver cabs ( I have a pair). 35hz is about right , almost an octave lower than a lascala.

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5 hours ago, Tizman said:

I was considering the Jubilee, but had heard that the dual mouths created issues with response.  These issues are avoided by the La Scala because of the joining of the two mouths, or so I read somewhere in these forums.

Most of the issues with the dual mouth W-section bass bins that have truncated mouths--like the Jubilee and Belle, can be addressed through adding a mouth extension--like the type shown in the Jubilee buyer's guide FAQ:

Levan2.jpg

 

To be honest, this is really an issue with free-standing bass horns used outdoors, and not so much inside rooms where nearby surfaces fill-in the polar narrowing at higher frequencies due to the dual mouth diffraction.  Another approach is to cross the bass bins at a lower frequency to avoid the polar lobing at higher frequencies, adding a lower midrange/midbass horn--like KPT-305s.  If you wanted to add the nose section to a Jubilee bass bin, this would completely address the polar narrowing issues at higher frequencies, but it also makes a much larger footprint, which is probably why no one that I'm aware of has tried to add a bass bin nose section. 

 

The La Scala already has a completed mouth section, but as I pointed out above, the last fold on the horn expands at a large enough rate that it would be much simpler to use the room's corners to extend the effective horn length.  The problem with turning La Scala bass bins around to face the wall is that you're also reflecting midrange frequencies up to 500-600 Hz off the corner walls/floor/ceiling, which is not desirable from a controlled directivity point of view.  

 

I'd recommend real Klipsch Jubilee bins (the clone plans posted on this forum result in a bass bin that have severe low frequency extension issues--in my experience--so I don't recommend them).  You can add a nose section if you plan to use them outside in PA fashion.

 

Chris

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Another way to avoid adding two more horn apertures above the bass bins (in order to avoid polar narrowing) is to turn the HF horn into an MEH (multiple entry horn), like the one in this thread: https://community.klipsch.com/index.php?/topic/161404-a-k-402-based-full-range-multiple-entry-horn/

 

New Center profile 500px.jpg

 

Then you can use two much smaller midbass drivers (a single 8" low compliance driver is what Klipsch uses in the KPT-305) in off-axis ports as shown the K-402-MEH thread, and extend the range of the K-402 with compression driver down to 200 Hz.   (I wouldn't try to do this using passive crossovers, but rather DSP crossovers are tailor made for this application.)  That way it can easily cross with a Jubilee bass bin thus avoiding the addition of any more horn apertures and getting full polar coverage throughout the critical midbass region.  I know that the K-402-MEH sounds extremely good in the midbass (about 100-250 Hz) and lower midrange (250-1000 Hz).  It has controlled directivity throughout both of those ranges (something that's difficult to find in fully horn loaded loudspeakers).  The K-402-MEH is another approach, using dual 15" woofers and placing it against a wall or in a room corner, it will cover full range (including subwoofer frequencies). 

 

Chris

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8 hours ago, Tizman said:

Thanks for all the replies.  I have some more interesting things to think about.  I was considering the Jubilee, but had heard that the dual mouths created issues with response.  These issues are avoided by the La Scala because of the joining of the two mouths, or so I read somewhere in these forums.  The idea of extending the horn loaded bass by adding to an existing cabinet is very attractive, as it is far less work than building an entirely new cabinet.  That said, the Beck California is something that I have been very interested in for a long time.  The California appears to be a relatively straightforward build, with one mouth and a horn loaded lower frequency that is lower than a jubilee bass bin.  Moray James has been suggesting it in these forums for some time.          

 

There are pics around of an LS with extended side walls, with a larger mouth (eliminates the short parallel sections as well). Not tested but sold and used for DJ use. Better to get the Jubilees and be done with it.

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5 hours ago, Chris A said:

Most of the issues with the dual mouth W-section bass bins that have truncated mouths--like the Jubilee and Belle, can be addressed through adding a mouth extension--like the type shown in the Jubilee buyer's guide FAQ:

 

Cris , the picture you are showing is a Levan Horn ,  the idea of Richard Long  of RLA in the late 70's for  the Paradise Garage  , he named it the Levan Horn in honor of Larry Levan

 

 

image.png.2b10db81c867689663acce04db910544.png

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34 minutes ago, Marvel said:

 

There are pics around of an LS with extended side walls, with a larger mouth (eliminates the short parallel sections as well). Not tested but sold and used for DJ use. Better to get the Jubilees and be done with it.

 

Even Jubes have their limits on LF. This graph I searched for this morning here on the forum from Roy Delgado. Jubes down 12db @ 30 hz. From 40hz they are rolling off hard.

 

khorn-jubilee LF range-source Roy Delgado.PDF

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40 minutes ago, Marvel said:

 

There are pics around of an LS with extended side walls, with a larger mouth (eliminates the short parallel sections as well). Not tested but sold and used for DJ use. Better to get the Jubilees and be done with it.

do you have any more specific details - pictures- articles or specs ------------when you say not tested but sold and used for DJ use , is that a klipsch made product - tx

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8 hours ago, Tizman said:

I was considering the Jubilee, but had heard that the dual mouths created issues with response.  These issues are avoided by the La Scala because of the joining of the two mouths, or so I read somewhere in these forums.

 

I don't have .00000030948% of the technical expertise as most of these other guys here do.....  so with that disclaimer, I've owned LaScalas for 41 years and Jubilee's now for roughly 13-14 years.

 

The Jubilee's simply outperform the LaScala in any way you want to cut it except for size!!!.

 

(and the Jubilee's get stomped by a double MWM cabinet!! so there is always a bigger dog around the corner!)

 

When I got my LaScalas, I demoted my Electrovoice Interface D's.  When I got my Jubilee's, I demoted the Khorns which I had bought between the LaScala & Jubilee purchase.

 

If you have the space & funds, I'd contend it's better/more efficient use of your funds to simply get a Jubilee than to reconfigure a LaScala that still might not give you want you want.

 

 

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46 minutes ago, Coytee said:

If you have the space & funds, I'd contend it's better/more efficient use of your funds to simply get a Jubilee than to reconfigure a LaScala that still might not give you want you want.

 

 

 

For sure. Today's music with synthesizers, EQ and better recording techniques, and not to mention your input music source @ home is 5 times better than it was in 1975. A vinyl album might have a dynamic range of 65 db. That is severely compressed by today's digital source file specs. Not to mention the snap, crackle, and pop.

 

Today's music reproduction @ home does not end @ 40 or 50 hz. Far from it. But a good sub is the great equalizer too, if properly integrated into the system.

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