New, to me, La Scala‘s

[Don McPhee]

OK so I have ended up with a pair of LaScalas  The type is LSBB and serial number is 22T696/7.  Now a couple of oddities at least at first glance these are of coarse a single cabinet design and the base bin interior is finished in black the rest of the cabinet is what appears to be like a  Walnut . I took a peek at the woofer and  they are Klipsch K 43E woofers Which from everything I read are the commercial offering. Upper drivers are k77 and k55v. 

 I had some K horns for sale and took these in along with cash in on trade and I am actually very surprised at the performance of these. They don’t go quite as low but the bottom end that they do provide is extremely tight punchy and accurate more so than the K horns. In the trade I did keep my Dean crossovers which provides a minus -6DB  on the mids which is very pleasing to the ear . 

 I am going to sit on these and listen to them and enjoy them for a bit and even though I have the bug to upgrade and help the bottom end I really don’t have the funds at this time to do so so sitting and listening to them are a great solution at this point. 

So if anybody could chime in and let me know exactly what I have that would be great.

 

Cheers

 

Don

[carlthess40]

Those are nice. Work with placement and that will help the low end. And there are a few post of a mid for the bottom of the box to turn the doghouse into a ported doghouse for lower end


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[carlthess40]

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[richieb]

 

* with all due respect and while adding a ported box under the LS cabinet may well give additional low bass response, considering that an “upgrade” is questionable.

[Marvel]

35 minutes ago, richieb said:

considering that an “upgrade” is questionable.

 

Debatable might be a better term. From responses on here of those who have tried it, far more have kept the changes in place than removed them.

 

This can be done with the ports pointing toward the front or back.

 

Someone did a very nice job fixing those up. Enjoy them the way they are for a while and get used to the sound. Your ears will give you a good idea how well they are working. Since you put in Deans crossovers with the mids pulled back, they are probably sounding really nice. A switch to a K33 woofer would give you a slight amount more bass,

 

Having K-43s in them, those may have been a set of one piece LSI models, so painting the woofer horn black would make sense (and easier that veneering them). Whatever, with the veneer and trim they are very pretty.

 

Bruce

[moray james]

nice thing about the riser mod is that it is so easily installed and de installed with no trauma to the cabinet, totally reversible.

[geoff.]

Ha, found the other post first.

 

On the fence about doing this to mine. Even though it is reversible, I could be fishing...

 

So what is the consensus on the mod?

 

How many have left it in place, and how many have reverted to stock? 

 

Does it take away from the punch that sets a folded horn bass bin apart from rest?

[Marvel]

The port depth can be adjusted. Most have favored a 7inch tube length. Helps with the bass and still has the punch of the horn. I don't know what the numbers, are but from what I have read on here, way more liked the mod.

[Ray_pierrewit]

I've done the mod, lived with it for several months, then took them off for a couple of weeks to judge the difference. I would definitely consider it an upgrade, having lost none of the "punchy bass" I loved with the stock LaScala. My next move, as soon as the opportunity arises, will be to build Claude's Q-Pie bin, which by all accounts is an even better "upgrade".  

[Marvel]

22 hours ago, geoff. said:

Ha, found the other post first.

 

On the fence about doing this to mine. Even though it is reversible, I could be fishing...

 

So what is the consensus on the mod?

 

How many have left it in place, and how many have reverted to stock? 

 

Does it take away from the punch that sets a folded horn bass bin apart from rest?

 

@DizRotus   Perhaps Neil can also comment.

Unfortunately, Dennis Kleitsch (djk) the originator of this mod has passed away. I can dig up all of how he set the tuning and everything for this mod, but he had said not one who did it ever went back. We know that some have, but most felt the mod was worth the work involved.

 

Bruce

[DizRotus]

22 hours ago, Ray_pierrewit said:

. . . lost none of the "punchy bass" I loved with the stock LaScala.

 

I agree.  Efficiency was reduced, but not significantly.   IMO, La Scalas benefit from a good sub(s).  Having a sub makes the bass mod unnecessary.  Without a sub, the bass mod is worthwhile and, as has been said ad nauseum, is easily reversible.

[Marvel]

7 minutes ago, DizRotus said:

as has been said ad nauseum, is easily reversible.

 

 

That's because you've been on here forever. 😉

 

Just to add... yes, a sub is better, but many folks don't have room for one or two, and this is less expensive.

[jason str]

I would use a bit of PEQ before porting personally to get that last bit of bass out but ultimately a proper horn loaded sub would be worlds better than either.

[geoff.]

Gentlemen, as always, thank you for your constructive input!

 

 

 

 

[Marvel]

Just some explanation behind Dennis' (DJK) bass mod for the La Scala. I believe he originally posted this sometime before 2005.

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The taper rate of a LaScala is 100hz. The mouth area is good for 125hz. Below this it is a big woofer in a small sealed box. If we plug the T/S parameters for the K33E into a box program we will see that the Qtc=.85, the Fc=82.5hz, and the F3=70.9hz.  If we close in the back of the high frequency cabinet and open the woofer rear chamber up into this volume and fill with fiberglass we now have Qtc=.577, Fc=58.2hz, F3=73.6hz. Bessel=Qtc.577=D2 gives the best transient response and the least group delay of all the sealed boxes. At 30hz the Qtc=.577 has 4.5dB more output than the Qtc=.85 .  
 
Compared with sealed enclosures,the transient performance of the best vented enclosure is worse than the best sealed box enclosure. Since we have made great gains in performance some may elect to stop here. But please read on. The next step is to port it. The K33E is not the optimum woofer for this but it works pretty good. With the box size optimized for a D2 we can port the stock woofer to an SC4. The transient response of an SC4 while not as good as an SBB4 (more on this later) is better than the more common QB3. Unequalized the F3=49hz and has 3dB more output at 30hz than the D2. The response curves are parallel with the D2 the only difference being the Fc being a half octave lower with the SC4 and the output being 3dB higher from 30~70hz. The output of the SC4 does not drop lower than the D2 until you go below 17hz.  
 
Again this may be a stopping point for some. But by adding a simple two pole high pass filter ahead of the power amp we can now have a C6 with a -3dB point of 31hz. Since this is the Fb of the system there is no increase in cone excursion or distortion. The filter consists of a cap, an inductor and a pot. The pot allows adjustment at Fb of +/- 3dB. This is similar to being able to change the Qtc of a sealed box from .5~1. 0.  
 
If you think about it we have the choice between a D2,SC4,and a C6 in the same box by plugging the port and/or bypassing the eq. If you have a SET amp or simply want to get the most out of the LaScala you will want to upgrade the woofer to something with a lower Qts. The Klipsch K43E does the trick, as do the EV DL15W and the JBL 2205. The EV and JBL drivers require some minor network changes. The lower Qts drivers allow for an SBB4 alignment which has the best transient response of the vented alignments.  
 
With no eq they have 3dB more output at 30hz than the stock woofer. With eq we have a maximally flat B6 and the F3 of the system is 27~28hz. If using a solid state amp with the low Qts woofers a small resistor must be added in series with the driver to have the same Rg as the SET does.  
 
This mod can be backed out of a stock LaScala with no externally visible changes if you don't like it. No one has ever gone back to stock after hearing this mod. Paul Klipsch was violently opposed to the venting of horn speakers based on his experience with venting the K-horn.  In retrospect it is easy to see why.  The 12" Jensen field coil woofer he was using had an Fs of 60hz and a quick calculation of the vent area vs the Vb based on the photographs of this experiment looks like an Fb of ~80hz. I am sure this sounded horrible. Paul Wilbur Klipsch is a giant in audio. If I appear to see farther than PWK it is only because I am standing on his shoulders.