Jubilee with out the backs - corner loaded Khorn style

[Guest " "]

Anyone build a Jubilee with out the backs - corner loaded Khorn style?

[djk]

Doesn't seem practical, the last segment folds back away from the wall.

[Coytee]

1. I seem to have a voice of memory in the back of my head that said they tried a couple exit angles and felt focusing them inward helped something or another? (all more technical than me)

2. If someone did cut off the outer panels, I wonder if they (someone not technical like me) would even notice the difference.....especially if they never had a chance to do a side by side?

3. Related to #2, I wonder if it would still be 'good enough' or perhaps still an advanced over the Khorn bass bin that it would still be a worthy project for kicks & grins?

4. The 402 (not that I think you'd use it) would perhaps look more ungainly on top of the narrow section of the Jubilee rather than the wider base []

5. I'd imagine that you'd be committed to a tighter corner placement than the actual Jubilee bass bin?

[Chris A]

Anyone build a Jubilee with out the backs - corner loaded Khorn style?

As a side topic of conversation (not to derail the main topic here...) have you ever thought of taking a La Scala bass bin and turning it around backward to face into a corner? The top of the unit must, of course, be able to be turned 180 degrees from the output of the bass bin to do this. You could even stack two pairs of bins on top to get more net sensitivity with lower distortion.

The only issue that I can see is making sure that there isn't anything between the two La Scalas to adversely affect the stereo imaging, since they will be lower than Khorns (assuming that a single pair of La Scalas are used in corners) and thus more susceptible to furniture/electronics racks getting in the way. One could even set up small false corners to increase the corner loading effect without seriously detracting from the decor or the sonic performance (e.g., diffraction, higher-order modes, etc.).

La Scalas used in this way could be called "the new Shorthorn". [] I'd bet that they would sound great--and the price is right...Just add your K-402 or K-510 horn with whatever compression driver suites your fancy, with your choice of active or passive crossover (Dx38s go for about $400-$600 on ebay).

Wait..wait...I think that I remember someone here (from Maine) that did just that-- and showed pictures of it.

Chris

[Chris A]

https://community.klipsch.com/index.php?/topic/93561-la-magic-or-listening-to-la-scalas-backwards/

Edited May 15, 2016 by Chris A

[sootshe]

Anyone build a Jubilee with out the backs - corner loaded Khorn style?

As a side topic of conversation (not to derail the main topic here...) have you ever thought of taking a La Scala bass bin and turning it around backward to face into a corner?  The top of the unit must, of course, be able to be turned 180 degrees from the output of the bass bin to do this.  You could even stack two pairs of bins on top to get more net sensitivity with lower distortion.

The only issue that I can see is making sure that there isn't anything between the two La Scalas to adversely affect the stereo imaging, since they will be lower than Khorns (assuming that a single pair of La Scalas are used in corners) and thus more susceptible to furniture/electronics racks getting in the way.  One could even set up small false corners to increase the corner loading effect without seriously detracting from the decor or the sonic performance (e.g., diffraction, higher-order modes, etc.).

La Scalas used in this way could be called "the new Shorthorn".    I'd bet that they would sound great--and the price is right...Just add your K-402 or K-510 horn with whatever compression driver suites your fancy, with your choice of active or passive crossover (Dx38s go for about $400-$600 on ebay).

Wait..wait...I think that I remember someone here (from Maine) that did just that-- and showed pictures of it. 

Chris

Don't waste your time..........yes, I've tried this too & initially thought it was great........after extended listening I found that the system had lost it's coherency..........the bottom end was awesome, but the imaging & the blend between the bottom end & the mids & tops just didn't gel together. I ended up with the bass reflex cab underneath & this is the best blend.

[Guest " "]

Turning LaScala's around into the corners is very relevant to the original question if you cut the sides to match the internal cuts of the Jubilee and and add the reflector that creates the last turn. You would in essence have what would look like a 2 ft wide Jubilee because the corner walls would now be the Back of the Jubilee cabinet. If you don't make these cuts, and add the last reflector, you will loose mid bass and lower mid range. I have been toying with this idea for quite a while. Stacking 2 of them would give you a Jubilee capable configuration. But, you'd be dependent on corners.

[Coytee]

Stacking 2 of them would give you a Jubilee capable configuration. But, you'd be dependent on corners

Thinking out loud here since I don't have a clue.

My understanding is they put two 12" drivers in the Jubilee instead of a single 15" driver to help raise the crossover point. The 12's go higher than the 15's. By putting two 12's in there, they kept the same (or more?) working area than a single 15.

Would two LaScalas with 15's go as high as the Jubilee bin with the 12's?

(would it matter if they did not since we're crossing the bass bins around 450hz??)

[Edgar]

Well, modeling shows that it's a bad idea. According to Hornresp, the cutoff frequency rises a bit,and the midrange response gets ugly.

Standard Jubilee in gray, modified in black.

Greg

[Chris A]

Greg,

Are you accounting for the corner effect in your Hornresp model?

Chris

Edit: Sorry, I see your parameter for this listed.

[Chris A]

The reason why I questioned the corner-space parameter in Hornresp is that the simulation that you show really doesn't look like what I remember the tested Jub bass bin performance to look like on the ends of the FR plot.

Chris

[Edgar]

A model can only crudely account for the infinite number of variables that affect the response. That's why it's best to compare models with themselves ("How did the model response change when I altered a parameter?"), rather than trying to compare them with reality.

Greg

[Chris A]

"...when the model fairly accurately predicts the actual performance...". If the model is far off from tested performance, then I have questions.

I have questions.

Chris

[djk]

Measurements done by PWK in fig.8 of the JAES article show the Jubilee down 5dB with respect to the 50hz~60hz region, this agrees very close with the general shape Hornresp shows.

Also keep in mind that the 0.5Pi model assumes the corner is made of something like depleted uranium (infinite density). A real life corner will not have as much gain, expect about 5dB less output below about 100hz in reality.

[Guest " "]

Greg

I'm looking at your graph which uses the existing Jub with k-31 internals minus that last turn, but relying on a corner with a last turn mod, and personally don't think the plots are bad. It barely looks like a 3 db diff and looks localized in the lower mid range area.

Do you have the info to re-plot using the LaScala internals, cab modified to look like a bigger Jub (v shaped cut of lascala exit side walls, tip extention to replicate the last turn, 2 laScalas positioned into corners.

[Guest " "]

[My understanding is they put two 12" drivers in the Jubilee instead of a single 15" driver to help raise the crossover point. The 12's go higher than the 15's. By putting two 12's in there, they kept the same (or more?) working area than a single 15.

Putting only one of anything would not make sense since you would have to run expanding ramps thru out most of the turns to make it work. Using 2 drivers, and ramps before the first trun allow this to have more slop.

[Chris A]

Measurements done by PWK in fig.8 of the JAES article show the Jubilee down 5dB with respect to the 50hz~60hz region, this agrees very close with the general shape Hornresp shows.

As I recall, anechoic measurement was used for the Jub in the JAES article, not corner space.

16 Dec. 2010 EDIT: Boy, did I get that one wrong. Figure 8 is shown for corner space outside, so the effects of room gain are not present, only corner loading.

Also, the high end performance is much better than this Hornresp FR plot shows.

I didn't get this one wrong, however. The Jub bass bin is down about --2 db at 1100 Hz in real life. That is a BIG difference.

But, what do I know...?

Chris

[Chris A]

yes, I've tried this too & initially thought it was great........after extended listening I found that the system had lost it's coherency..........the bottom end was awesome, but the imaging & the blend between the bottom end & the mids & tops just didn't gel together.

 

Did you correct for the bass bin delay? This is a similar complaint that I hear leveled at the Khorn, and next to no one is correcting for bass bin delay.

 

Could it be because the La Scalas have no "tailboard" assembly to separate the two mouths. PWK warned about this condition in his "Dope from Hope" articles from November 1961, and recommended that a seal be used to keep the two bin exits sealed from one another, especially if the Khorn is not centered in the corner, i.e., if it is rotated such that one exit is larger than the other (usually by pointing the Khorn "downrange" or "uprange" more than 45 degrees from either wall).

 

Have you heard Khorns vis-a-vis La Scalas? They don't sound the same.

Chris

Edited November 22, 2014 by Chris A

[Chris A]

Putting only one of anything would not make sense since you would have to run expanding ramps thru out most of the turns to make it work. Using 2 drivers, and ramps before the first trun allow this to have more slop.

Interesting - I haven't seen that point of the design before. The Jubs have ramps in the first bend but none thereafter, I believe.

I'm told that the resulting more-consistent flare rate (i.e., reduced "rubber throat" rate of change of flare rate) of the Jub is said to reduce resulting harmonic distortion products and increase efficiency of the Jubs relative to the Khorn bass bins.

Chris

[Guest " "]

This drawing which was on the forum, best explains. the internals of the jubliee and the LaScala except for the first turn reflector, and the last turn reflector, are basically the same. Many of the Heritage products use the same "design" things.