Jubilee 2-way Horn Question

[Deang]

how did you get 36x20

Maybe he was thinking of the mouth size -- 36 feet by 20 feet.

[D-MAN]

I'm still wondering about why one would want to pursue the technology of the 1930's compared to what can be done with today's drivers?

I really think that crossing over lower is a mistake, after all, they ALL did it in the old days, and everyone (PWK especially) eventually went the other way when technology advanced enough to crossover higher effectively!

So now that it can be done, there are those who specifically WANT to go "back" to the old days? Hmmmmm....

The main point I am saying is that it's been done (to death) and NONE of the speakers that did it are alive today! And the reason(s) for that is....

DM

[jwc]

So Mike, you are taking a stand and saying you don't prefer the K402 and prefer something different? I must be missing something here.

The total width of the K402 horn is 40". The mounting "rim" around the horn is about 2"......no flare there. So I am saying the width of the horn is 36" unless you want to say the mouth of the horn goes out to the edge of the horn. If so, then it is 40" width horn.

jc

[mikebse2a3]

40x20 is getting rather beamy, which would be good in a large reverberant field. To borrow some terminology I've seen used recently, the typical home listening environment is actually semi-reverberant...meaning wider dispersion is better because it allows you to more easily recover some of the "reverberant" attributes that are lost by the small space. To put it another way, wider dispersion better "fills" the room with sound. But too wide and you really start increasing the Haas effect which will start to require acoustical treatment. Too narrow and the sound is just thin and feels like it's being thrown at you.

Btw, I think the K402 is essentially 90x60 from 500-20kHz (Roy's measurements)...how did you get 36x20?

Looks to me like Mike is talking about dispersion angles in degrees. ie: 90 degree by 60 degree

jc is talking about mouth size in inches.

mike tn[]

[jwc]

That's it. No wonder I was so thrown off.[]

Case closed.

[bodcaw boy]

Good question, I have seen references to "smaller" horns, but don't see any in the commercial catalog.

Anyone know the other options, their size, cutoff, and availability/cost?

Hi Biggerisbetter,

finally in town for a couple of weeks. i did find out that the 402 horn cannot be purchased without a driver. sorry. it maybe worth to buy it with the driver and then sell the driver later.

as to the smaller horn, it is called the kpt-904-hf. because the jub lf has extended top end response, it is alot more flexible in choosing crossover points so that you can you large horns, medium horns and small horns. it would be somewhat wise to match the coverage angle in both planes when choosing the crossover freq though.

berryboy roy

[DrWho]

That's it. No wonder I was so thrown off.[]

lol, me too! []

[BiggerIsBetter]

Thanks for checking Roy, I greatly appreciate it. There is a good chance I will take you up on the offer to buy the set and sort it out from there.

I have the smaller round 400hz tractrix so I will start there. Maybe those little horns will sound great and end my persuit for a lower crossover. I doubt it!!!

More to come......

[Chris A]

This thread appears to be an example of "design by committee".  To me, it shows how good ideas are easily trampled in the mud before they even get a chance to see the light of day. "Requirements memes" seem to creep into the design space that aren't true...but are held to be true nevertheless by those that haven't actually checked their validity.

 

On the other hand, bad ideas/designs also seem to get pushed along--that really shouldn't.  That includes designs that incorporate requirements that really aren't requirements.  It takes a fair amount of insight and knowledge of physics/acoustics to be able to discard bad requirements and ideas--and recognize other requirements/design space that no one else sees.

 

I didn't read this thread before starting the K-402-MEH concept, design, and prototype testing: If I had believed everything in this thread, I'd have been dissuaded from trying it before even getting it down on paper.

 

It's an interesting case study.

 

YMMV.

 

Chris

[Chris A]

On 9/21/2006 at 4:58 PM, bodcaw boy said:

It would be somewhat wise to match the coverage angle in both planes when choosing the crossover freq though.

 

FYI...One advantage of the multiple-entry horn (MEH) design is that any crossover frequency that you choose will have matching polars--by definition.  There are no polar lobing issues at the chosen crossover frequency band because the acoustic centers at the horn profile are effectively located at the same x-y position in space, i.e., effectively a point source horn.

 

Chris