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Tizman

Extending La Scala bass bin

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I asked the question about extending the La Scala bass bin to see if their was anyone with experience with it, and to gain the knowledge that a discussion would generate, but I should probably let you all know what it is that I am after.  I am working on a project that will use a bass bin and a K-402 as a two way in stereo with a single very large bass horn for the lower frequencies.  The goal is to achieve the best possible sound quality I can in a room of roughly 30' X 50' with 10 foot ceilings.  I am not looking for maximum SPL, SQ is the priority.  So far, based on extensive research on this and other forums (and assuming that a MEH is not used) that has led me to a Jubilee for the two way.  The remaining question is whether or not I should use a different bass bin with the K-402.  My concern with the Jubilee bass bin has been addressed by ChrisA...      

3 hours ago, Chris A said:

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.

That said, would I be better off with a Beck California bass bin?  Moray James is definitely a proponent.  A pair of Jubilee bass bins are triple the money of what it would cost to have a pair of Californias built.  That said, SQ is more important than cost in my case.  Also, MWMs are just too big for my application.  The big bass horn is another thing entirely, as is it's integration with the two ways.... 

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Screw the LaScala.....screw the Jubilee....

 

Get/make a pair of double MWM bins and forget about it! 

 

Pic might give you a reference as to various sizes (LaScala vs MWM doubles)

 

Note that the K402 is HxW actually LARGER than the LaScala's HxW.  Put that in your tweeter!

 

 

outside.jpg

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12 minutes ago, Tizman said:

MWMs are just too big for my application

 

In a 30x50?

 

Yikes!!

 

 

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3 minutes ago, Coytee said:

In a 30x50?

By too big, it's also optics that I am referring to.  It is important, in my case, that the two ways look like something that the average person might put in their home.  Jubilees are very borderline.  MWMs are out of the question.  I will be using a huge horn for lower frequencies.  Wouldn't the only difference between a Jubilee and a MWM, in my application, be the required crossover frequency to the big bass horn?  Is the MWM superior in ways other than low end extension?

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MWMs / 402s behind fabric drops with Bose 901s painted on them.  There's your aesthetics!

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1 hour ago, Randyh said:

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

 

Not a klipsch product... a member's build. I'll try to find a pic.

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I could be convinced into MWMs.  They do cost a bit less than the Jubilee bins.  I'll have to consult with the boss.  A couple of photos courtesy of Coytee...  

jubilee.jpg

mwm k402.jpg

Are there any differences other than low end extension?

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1 hour ago, Tizman said:

That said, would I be better off with a Beck California bass bin?

I guess the point that I was making is that the W-section bass bins are limited on their top ends not by SPL roll-off, but rather polar lobing and narrowing of the front lobe.  The best way to avoid that is to use a bass bin that doesn't have two mouths, or if using two mouths, make sure that the mouth isn't truncated like the Jubilee, Belle or MWM bass bins.

 

Your idea to use a University Classic-type of single horn mouth has merit, but note that there isn't any data on its polar performance, SPL response, and phase response of that bass bin, and that's a significant factor in making a choice among bass bins.  I know the response of the Jubilee bass bin and to a somewhat lesser degree, the MWM, and both are good performers. They just have a high end crossover point that likes to be below 300 Hz due to polar lobing issues.

 

For your application, you haven't stated what kind of subwoofers you're considering, or whether the music that you play doesn't require response below 40 Hz. This is also a big factor.  The MWM begins to roll off at 50 Hz, the Jubilee at 40 Hz, and the La Scala/Belle bass bins at 70-80 Hz.  In my room, the added 10 Hz of bass extension of the Jubilee bass bin is a big deal, as most "urban contemporary" and other accentuated bass genres roll off at 30 Hz, and corner loading the Jubilee bass bins gets you to 30 Hz with a very small PEQ boost at 31 Hz.  The MWMs wouldn't be good candidates unless a significant lengthening of the horn path in the form of an added nose of significant dimensions were added (i.e., "Super" MWMs). I use tapped horn subs crossed at 40 Hz, and this works extremely well.  Jubilee bass bin fidelity below 100 Hz is basically unsurpassed down to 30 Hz, and this low crossover point works quite well. 

 

So bottom line: based on my very limited understanding of your application, I'd put the choices this way:

 

1) Jubilee bass bins with nose extensions (to solve the polar lobing issues up high)

2) Jub bass bins without nose extensions

3) MWMs with nose extensions (to solve the polar lobing issues up high)

4) MWMs without nose extensions, leaving the issue of how to cross them effectively with K-402s (usually KPT-305s will be required)

 

All of these rankings are based on multiple decision criteria of a) sound quality, b) bass roll-off points--high and low, and c) polar coverage.  Also , d) the Jubilee bass bins are a lot nicer to look at indoors (IMO).  MWMs aren't indoor loudspeakers in my experience because they are just too wide and unwieldy to handle (even singles, which are much harder to find).

 

In terms of low cost: MWMs will win since they can be had for almost nothing (i.e., "come and take them away"), La Scala bass bins are the next lowest cost, and Jubilees are the highest cost. 

___________________________________________________________________________

If I were going to do what I think you're wanting to do, I'd make the K-402s into K-402-MEHs so that you can easily get the crossover frequency with the bass bin down below 200 Hz.  No nose extensions are required on the bass bins and the resulting sound will knock your socks off.  Then everything works like a charm: smooth and consistent polar coverage all the way up and down the audible spectrum--out to a nominal 90 degrees of coverage angle.

 

Chris

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29 minutes ago, Chris A said:

MWMs will win since they can be had for almost nothing

I'm in Toronto, Canada.  I have never seem one available used since I started looking about a year ago, at any price.  If there are any members that have a pair for sale (or know of a pair) within reasonable driving distance of Toronto, please let me know.

 

18 minutes ago, babadono said:

Thought they was unobtanium.

I believe they can be purchased from your local Klipsch Pro dealer. 

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38 minutes ago, Chris A said:

2) Jub bass bins without nose extensions

It would seem that this is my best choice if I am going to purchase a product that doesn't require modification.

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40 minutes ago, Chris A said:

I'd make the K-402s into K-402-MEHs so that you can easily get the crossover frequency with the bass bin down below 200 Hz. 

I have followed your work on this approach with much interest.  The issue that I have with it is that it requires extensive modification of the K402.  It would be myself doing it and, frankly, I am worried that I will mess it up.  

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31 minutes ago, Tizman said:

It would seem that this is my best choice if I am going to purchase a product that doesn't require modification.

The midrange crossover point polar coverage issue is basically unknown among Jubilee and MWM enthusiasts.  This is something that the 1% of the 1% that owns well implemented horn-loaded loudspeakers might want to address.  This is not immediately obvious, or even obvious at all to most people at any time.  If you can't hear this, then it, by definition, isn't an issue.  If it isn't then the Super MWM comes back into solution at a higher ranking, and the MWM without a nose also does better in the rankings.  However, that extra 10 Hz on the bottom end of the Jubilee, in my experience, does make a difference.

 

Also note that a bass bin nose extension may be mitigated (Jubilee or MWM bass bins) if you do one thing: lower the K-402 horn by about 10 inches and allow it to stick out in front of the bass bin front panel, then use lower order crossover filters between the K-402 compression driver to fill in the polar lobing at the crossover frequency. This little trick was something that became much clearer when doing the K-402-MEH crossover.  It works well to fill in the frontal lobe size around 300-500 Hz. It also significantly reduces the phase growth through the crossover region, and that made a huge difference in sound quality in my listening room.

 

Chris

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21 minutes ago, Chris A said:

Also note that a bass bin nose extension may be mitigated (Jubilee or MWM bass bins) if you do one thing: lower the K-402 horn by about 10 inches and allow it to stick out in front of the bass bin front panel, then use lower order crossover filters between the K-402 compression driver to fill in the polar lobing at the crossover frequency. This little trick was something that became much clearer when doing the K-402-MEH crossover.  It works well to fill in the frontal lobe size around 300-500 Hz. It also significantly reduces the phase growth through the crossover region, and that made a huge difference in sound quality in my listening room.

 

Chris

Thanks for reminding me.  I have seen you mention this in other threads.  I will be using a three way electronic crossover on this project, and will be using a single, very large, 30HZ horn between the two two-ways.  The crossover will include the delays needed to place the K402 where it is required, and to adjust the large bass horn's delay as well.  If I do what you suggest above, will that for all intents and purposes effectively mitigate the issue with the dual mouths of the Jubilee bass bin?  For the 1% of the 1%?

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Yes, it did for me.  I can't detect the midbass/midrange polar lobing now.  I haven't done polar measurements in-room for the Jubilees in their current configuration, but I can say that the midrange and upper midbass is very close to the K-402-MEH--something that I couldn't say before the lowering of the K-402s and the phase flattening of the crossover filters.  The K-402-MEH won the midrange sound contest beforehand.  Now--it's very difficult to hear any difference at all.

________________________________________________________________________________________

One thing that I should mention--that's really been driven home in the last week or so for me:

 

Most audio enthusiasts are content with sitting in a chair squarely on centerline between the stereo loudspeakers at 8-12 feet distance from the loudspeaker and making all of their judgments on sound quality based on that type of "head in a vise" approach to audio. 

 

With K-402s and Jubilee bass bins (and this includes the K-402-MEH), anywhere you stand or sit in the room is roughly equivalent.  It does sound better in the main listening chairs 10-12 feet away and centered in front of the frontal three loudspeakers, but anywhere else in the room is also really good, too--enough to stand and listen in those different locations. 

 

This is stark contrast to the time-aligned/tri-amped Khorn clones that I dialed in over the past couple of weeks, (and am in the process of converting over to stacked/winged AMT-1s with Khorn (clone) bass bins).  If you weren't sitting in front of them in the right place, they really didn't sound tonally balanced or with enough high end sparkle to identify them as higher sound quality loudspeakers.  If you weren't listening in a head-in-a-vise style, they really weren't very enticing to listen to. The story is completely different for the Jubs/K-402-MEH across the front of the main setup.  Sure, the difference in room size does make a big difference (the Khorn clones are in a much smaller room), but not that much difference in sound quality. 

 

I can't really emphasize the difference that that sound quality makes: it's like comparing a small hi-fi system at home with a commercial cinema where all the seats sound just as good as the next seat.  In terms of developing a sense of confidence in the sound quality exhibiting the highest clarity and balance (i.e., trust in what you're hearing is the way that the music was placed on the music media, that you're listening to reference quality sound) there is no comparison with other systems.  This is the real difference in sound that I experience with the setup.  It didn't get that way by "accidental synergy of components collected into a sound system".  It took guys like Roy, et al. a lot of effort to be able to hear that level of sound quality in-room.

 

Chris 

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20 minutes ago, Chris A said:

If you weren't listening in a head-in-a-vise style, they really weren't very enticing to listen to.

For the application I have, having a huge sweet spot is crucial, as the listening position should include the whole room.  Thanks for helping me hone this to something I can move forward on.  I have a quality two way crossover, but will need a quality three way for this system.  Any recommendations?  

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1 hour ago, Chris A said:

 

I can't really emphasize the difference that that sound quality makes: it's like comparing a small hi-fi system at home with a commercial cinema where all the seats sound just as good as the next seat.  In terms of developing a sense of confidence in the sound quality exhibiting the highest clarity and balance (i.e., trust in what you're hearing is the way that the music was placed on the music media, that you're listening to reference quality sound) there is no comparison with other systems.  This is the real difference in sound that I experience with the setup.  It didn't get that way by "accidental synergy of components collected into a sound system".  It took guys like Roy, et al. a lot of effort to be able to hear that level of sound quality in-room. 

 

That doesn't happen without a lot of precision "in room" measurements, time, thought, corrections, and experience. Most of us are not even close.

 

But I did have a revelation this week. I purchased a good set of over the ear wired headphones fed a signal from my portable Cowon high res digital player. Oh my......the sound stage presence, stereo signal separation, and overall sound quality is just amazing! 15 to 20khz response range. I just don't want to take them off. I don't believe any "in living room" 2 channel stereo system will ever sound as good.  No coloration from the room acoustics or objects/furnishings in the room. It will make you shake your head and think why not just listen to my music via headphones all the time? Well after 2 or 3 hours, you have to take a break anyways, give the ears/head a rest.

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