Jump to content
The Klipsch Audio Community
Sign in to follow this  
Cantilope

Building a Belle

Recommended Posts

I love a build thread! I hope to see lots of build pics.

Dave

I agree thats what has drawn me to this forum

Sent from my SM-N920P using Tapatalk

Share this post


Link to post
Share on other sites
Guest David H
I just picked up a MiniDSP 10x10HD for $700. Hopefully I can get it to do what I need it too.

 

 

I am sure that will do.

 

I like the Mini DSP's, but actives give me a head ache. I am not a set it an forget it kind of guy, always tweaking.

 

I went back to passives after several years with actives, and am much happier.  Back in the single amp camp.

 

Dave

  • Like 1

Share this post


Link to post
Share on other sites

 

I just picked up a MiniDSP 10x10HD for $700. Hopefully I can get it to do what I need it too.

 

 

I am sure that will do.

 

I like the Mini DSP's, but actives give me a head ache. I am not a set it an forget it kind of guy, always tweaking.

 

I went back to passives after several years with actives, and am much happier.  Back in the single amp camp.

 

Dave

 

I really think I am the same... but I must go through this to prove it to myself.  Great reminder though, that I should hold off on any amp purchases...  Plus I have been reading the thread about the guys making the hand made x-overs... that thread confused me right out of a purchase.

 

Your point is one of the reasons I decided on the Mini.  I have a 5.1 home theater, and my Sunfire pre-amp is a bit long in the tooth.  It has choice-less bass management and I have no room correction.  If my research is correct, if I am unhappy with the DSP as an active crossover, the unit it capable of being reprogrammed and stepping in and fixing that as well.  Seemed like it was a safe bet with multiple uses.  I also picked up the mic and REW.  I am hoping the education I am getting will help me understand this hobby better.  The best advice I need to heed for myself, take a moment and fix the rooms before I get much deeper.  I have one good room and one bad, that difference is bigger than any speaker or amp combo.

 

Build update:  On Friday I installed Eminence Kappa 15"s into the Belles to see if that's what I want to run (per ClaudeJ advice).  I am very happy with the new sound, it is as he described.  I think I gave up a little bit of the bottom end but the upper end is much punchier.  So I just bumped up the xover to the THT a bit.  It made a perceivable difference in the quality of the mid-bass and was only $110 each.  I am now 100% happy 500 hz and below, Skrillex is unbelievable as is Patrica Barbers Nardis, I think I have the best of both worlds.

  • Like 1

Share this post


Link to post
Share on other sites
Guest David H

You are on a path that is not only going to be educational, but enjoyable.

 

BTW, keep the original K-33's.  I tried swapping them out once, and thought the sound was an improvement for a while, eventually went back to the originals. This was on a Lascala, however the Belle is in the same ball park. On the other hand, have had good success with the 15C on Cornwall projects.

 

I am anxious to see your progress.

 

Dave

Share this post


Link to post
Share on other sites

Can someone please explain to a noob the math for the Belle folded horn? I know this thread is a bit old, but seems like a good place to ask about the dimensions calculations.

In particular, I don't understand why the horn constricts to 2.75in after the throat is 13x3in, but maybe I am not calculating the volume or crosssection correctly - or, more likely, I just don't have a clue. Also, it seems like the compression ratio with a K33 is about 4:1, that seems high.

Maybe I just need pointed to a primer. Y'all seem to have a great community here and I have always admired Klipsch, the man, the company, and the speakers. Thanks for all your posts.

Share this post


Link to post
Share on other sites

Can someone please explain to a noob the math for the Belle folded horn? I know this thread is a bit old, but seems like a good place to ask about the dimensions calculations.

In particular, I don't understand why the horn constricts to 2.75in after the throat is 13x3in, but maybe I am not calculating the volume or crosssection correctly - or, more likely, I just don't have a clue. Also, it seems like the compression ratio with a K33 is about 4:1, that seems high.

Maybe I just need pointed to a primer. Y'all seem to have a great community here and I have always admired Klipsch, the man, the company, and the speakers. Thanks for all your posts.

 

My take is that since this bass horn splits after leaving the throat, the point at which you're seeing the 2.75" dimension would actually be twice that, or 5.5" if not split.

Share this post


Link to post
Share on other sites

Then it would be13x3 to 6x21 [39 < 126 sq in]

and then 5.5x21 to 20.5x21 [115.5 < 430.5 sq in]

If considered 2 horns the second compression would be 126/115.5 = 1.09. So, maybe it is just important that it is >1.0. Did Paul Klipsch describe the folded horn this way? Which papers or books are best to read?

Horn A = 39/126 = 0.3095 throat to mouth ratio

Horn B = 115.5/430.5 = 0.2683 throat to mouth ratio

Are these ratios important? Sorry to ask such fundamental questions - haven't found the right materials yet. (also wondering about the accuracy of the drawings in this and other threads) I am considering some custom cabinets slightly scaled up from the Belle. I heard a pair of Belles in 1983 and thought they were great. I have always wanted that 'live presence', like someone is sitting there at a piano.

Thanks again!

Share this post


Link to post
Share on other sites

A few comments.

There are two "split" paths in most Klipsch bass horns. This is so that the bend after the first flare is effectively narrower. This prevent destructive interference where the sound is going round a bend. The inner radius and the outer radius are less different in length. Granted, the inner section of the curve is more like a zero radius.

The LS, Belle, and K-Horn have 0.5 square foot throat and a 4.0 square foot mouth. I.e. 1:8 ratio.

Harry Olson's 1957 big book (400 odd pages) (correction, 800)  available on line (free) but I don't have a link right now.

He examines horns of different lengths. He has a comment that only the short ones (not too great a ratio of throat to mouth) (correction mouth to throat) have appreciable loading below cut-off i.e. higher resistive loadings. The illustrations of throat impedance are too small to really examine. But this shows that short bass horns may well work better than long ones below cut-off. Below cut off the horn is working more like a duct for a direct radiator. Longer horns give better loading just above cut-off (Fc).

But I suspect this is why PWK was content with his relatively short bass horn. He wanted loading below Fc. He has an article showing restive loading below Fc.

Olson also shows how a chamber in front of the driver and before the throat can be used to increase driver output is sagging.

For the Klipsch driver that would be above about 200 Hz mostly because of the mass of the driver. Don Keele's article on use of direct drivers for bass horns calculates this from T-S parameters.

The theory (Olson's) is to set up a resonance between the driver moving mass and the compression in the chamber. At one time I worked out the acoustic reactanes (mass and chamber size) at 350 Hz (where the resonance gooses up the output and it was close to matching reactances. (Which is resonance.)

Please consider that matching the driver mass and the "back" chamber boosts low bass freqs, same idea for upper bass freqs and using a front chamber.  (Edit, like a CW bass reflex).

For the front chamber size you have to look at the "chamber" formed by the front  hollow of the diaphragm and the extra thick gasket to estimate the volume of this chamber. This means that drivers with other moving masses will not create the required resonance where in freq it is require. Maybe some here can do this calculation. It looked good on a SPICE simulation using Keele's circuit for the driver and front chamber.


My guess is that PWK realized this could be used in his bass horns. The problem is that the bass driver effective area is about 1 square foot or less. So the chamber would be about 1 square foot on one side toward the driver and 0.5 square feet at the throat. This can't be very effective as a compression chamber. It is more like a very short tapered tube.

My guess is that PWK put in what I'll call the restrictor plate so the front of the chamber formed is 3 x 13 rather than 6 x 13 (throat size). That way we form an effective chamber. Data from Klipsch shown in the Throat Size Riddle article shows how output above 250 Hz is indeed increased. But PWK never said this was his technique. (I may not have mentioned this specifically here before.)

WMcD

Edited by WMcD

Share this post


Link to post
Share on other sites

The book is here and can be downloaded as one big pdf.

http://babel.hathitrust.org/cgi/pt?id=mdp.39015050426579;view=1up;seq=136

See pg 112 about length of horns and Olson's comment.

Just to tell a story. Decades ago I was hunting down the book at Chicago libraries. DePaul was supposed to have it but it was missing. Illinois Institute of Technology didn't have it according to their paper catalog. But then I was browsing for something else at IIT and there it was. There were markings that it was owned by DePaul.

I dunno. Maybe someone returned the book to IIT in error and they put it on their shelf under the standard library of Congress call number.

WMcD

Share this post


Link to post
Share on other sites

I thought de Paul from Hope wrote de book on speakers.

Edited by DizRotus
  • Like 1

Share this post


Link to post
Share on other sites

Down near the bottom of this thread I compared the 1:8 ration of Klipsch speakers to Olson's horns.

https://community.klipsch.com/index.php?/topic/158330-bellela-scala-folded-horn/?hl=olson#entry1903355

Later people took me to task about my estimation of a -3 dB response. You can see my calculations. Penmanship is poor because of blood pressure meds.

WMcD

Edited by William F. Gil McDermott

Share this post


Link to post
Share on other sites

Excellent. I can't download the book, but I can read it on the site. I think I know where to find a copy. Thanks!

Interesting story, I see the copy that google digitized was from U. of Michigan. I will also read the thread referenced.

Do you think that PWK engineered the Belle, given the name, or another engineer that might still be around...I guess I would love to see a blog: "The Engineeering of the Belle Klipsch Loudspeaker".

Share this post


Link to post
Share on other sites

I'm not aware of anything specifically on the Belle. I can only imaging that PWK did the most of the work himself.

There is an article on the LaScala which I posted long ago.

https://community.klipsch.com/index.php?/topic/53241-article-aes-preprint-re-lascala-by-pwk/?hl=%2Blascala+%2Bpreprint+%2Barticle+%2Baes

Rumor is that the LaScala was designed to be cut from two (or so) sheets of plywood. It uses the K-400 mid-horn.

It is also common thought that PWK wanted to make a more pretty version for center channel use -- the Belle is a beauty. He made it only 18 inches deep and this required the K-500 horn rather than the K-400.

Maybe someone assisted PWK. OTOH, I'd suspect it was his own creation. "A camel is a horse designed by a committee." The Belle is a thoroughbred.

"W" type bass bins are fairly common though I don't know the state of affairs at the time of the LS.

It seems to me there is not much magic in LS versus Belle bass horn. Once you have a throat size as determined by the driver, and a mouth size, you have to approximate an exponential expansion. The Belle may be farther from exponential along the length than the LS.

WMcD

Share this post


Link to post
Share on other sites

With such short horns and rellatively low upper cutoff horn flare really does not matter that much. I have been playing around with LS in Hornresponse and with set mouth, throat and length the horn is mosty set response wise. Flare, driver and backchamber do change it a bit but not much.

Share this post


Link to post
Share on other sites

Wonderful-thread!

What I have to add is that, there is _no_ _such_ _thing_ as a box that is too-well-built.

Yes, of-course, angels, heads of pins--all-that.

It turns-out to be about Stiffness.

Marine-ply. Or perhaps Baltic-Birch. Many-many-layers.

The research has been done. It's Out There.

I'll not "advocate" for a single thing -- except (perhaps?) that anyone (everyone?) should take the Time to research the Problem.

Hint: keywords -- "modulus of elasticity" <-- aka Modulus.

Upshot? Use _great_ ply. it's _always_ worth whatever it costs!!!

  • Like 1

Share this post


Link to post
Share on other sites

Update on my Belles, which has morphed into a bit different project, but here is a list of the parts I have compiled and is what I have implement into my Belles which are 3-way tri-amped (4-way if you include the Tuba THT).

 

Schitt SYS Passive Pre-amp (volume attenuation)

Xilica XP-4080 DSP active Xover

(2) First Watt M2 25 Watt amplifiers

Eminence 15" drivers (after 3 months in service I like the K-33 better)

TAD 4002 drivers (no horns yet)

 

I have the Passive Pre-amp feeding the DSP which feeds the M2s.  The pair of M2s run the Mid and Hi and I am using a McIntosh MC2205 for the bassbins.  Out of the DSP I also feed a Crown XLS1000 which powers my Tuba THT.  I have 4 in and 8 out, so if you get a DSP get one with as many outs as you can, all of my outs are already used up.  I am very happy with the sound I have today, although I will still go 2-way, for a stop gap, this is a great place to be.  Time alignment is real and I have heard it and getting that right is a big part of what makes this upgrade worth it.  It sounds amazing, and I have given up on the MiniDSP, don't buy these for this type of use.  They can't hang on the mid and hi and sound horrible compared to the Xilica.  Fine for sub system but that's it.  I can't hear the Xilica at all its a really nice unit and can be accessed through CAT5 in addition to USB and the front panel and gives me the ability to REW.  I had no problems entering the numbers used by other members here using different DSPs like the DX38.

 

My project may take a significant detour.  The price difference between a K510 and a K402 is not that much and I believe to be worth the extra, so I am very much considering K402s (I already have TADs).  I quick comment on power requirements, after removing the passive xovers from the Belles and going straight from the woofer to the MC2205, I turn it up to the point I think I am going to cause those woofers to pound themselves out of the bassbins, I am hitting a whopping 25 watts on the dial, when I do go 2-way the 25 watt M2s ought to still give me a plenty of bass oomph and I could take the Mac out of the system and simplify the gain structure.

 

Since this is a build thread... I framed my basement into a 16'x28' room with Rockwool sound deadening insulation and some cool Hue lighting.  I have started on the wiring and still need to sheetrock.  This room is being built for this project and a dedicated listening room.  Which has slowed down this project, but I don't think it is worth chasing my dragon, without a solid room.

  • Like 3

Share this post


Link to post
Share on other sites
...Time alignment is real and I have heard it and getting that right is a big part of what makes this upgrade worth it. It sounds amazing...I can't hear the Xilica at all...it's a really nice unit and can be accessed through CAT5 in addition to USB and the front panel and gives me the ability to REW. I had no problems entering the numbers used by other members here using different DSPs like the DX38.

 

[A] quick comment on power requirements: after removing the passive xovers from the Belles and going straight from the woofer to the MC2205, I turn it up to the point I think I am going to cause those woofers to pound themselves out of the bass bins, I am hitting a whopping 25 watts on the dial.  When I do go 2-way the 25 watt M2s ought to still give me a plenty of bass oomph and I could take the Mac out of the system and simplify the gain structure.

 

Good points to make.

 

Start with a good digital crossover--it's critical.  To those that try active crossovers--I'd recommend not using miniDSP, Behringer, or DBX Driverack.  Instead, I recommend anything by ElectroVoice, Ashly, Yamaha, and Xilica.   The last two brands use 24 bit, 96 kHz sampling and that seems to be the final dividing line between complete transparency (as in, you can't hear it at all) and very adequate transparency.  The 24/96 units beat passive crossovers in every way, IMHO, since they are immune to noise and can correct the frequency response and phase of loudspeakers easily, something that passives by themselves don't do, in fact they insert additional phase delays that require all-pass filters to take out again.

 

Second point: effective amplifier power using active crossovers is at least doubled to each driver. The amplifiers also have better damping control over the individual drivers--helping the sound to be much cleaner.  If you like using your favorite fleawatt or tube type amplifiers, then you'll be pleasantly surprised to have (effectively) twice to three times the effective output per driver, never having to worry about amplifier output power again.

 

Ref: Active Bi-amping/Tri-amping FAQ

 

Chris

  • Like 1

Share this post


Link to post
Share on other sites

What happened to the bump button, I kind of liked it.  Anyways bumping for research.

Share this post


Link to post
Share on other sites

I believe the "Bump this topic" button appears only to the starter of the thread to be bumped.

post-6832-0-84260000-1454646497_thumb.pn

Edited by DizRotus
  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...