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Building a " Belle " ?


Dale W

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On 8/8/2004 1:32:37 AM formica wrote:

Ok, here is the second plan revision... and here are some of the questions I came up with when tring to add some detail. BTW, the plan is a little big for just one image, so I split in two for now.

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12) On my old Khorns the top grill is actually set in about 1/8", is the Belle like that? 3/8"

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Seems like a lot... esp compared to the pictures

*********Looks like about an eighth to me

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14) The motorboard and 'grille' are one and the same. See attached photo. It is basically a 3/4" piece of ply with openings cutout for the two horn lens', then the cloth is stapled to this. The sides are constructed from what looks to be 2x4's, with the 3/4" ply glued and screwed to these 2x4's.

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Do you know the depth and width of this pine 2x4 (is it 3-5/8" x 1-1/2"?)

************ What I'm wondering is how it's secured to the upper section

************ I don't think the L x W diminsions are critical. I'm planning to

************ use left over pieces of hardwood plywood to make it what ever it

************ needs to be. The vertical dimension needs to be right.

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5) I am assuming that the throat cavity opening is the typical 3" x 13" one used in the Khorn and La Scala. If so, then there is a capacitance associated with the 13-3/4" circular opening in the motor board.

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I was wondering the same thing if the Belle has a 3"x13" slot? I'm also unsure about the "gasket" with the 13-3/4" opening... as I seem to remember on how a similar gasket was used on some of the early k-horns, and it did (questionably) change the drivers performance.

*********** I think that gasket deal has been abandoned, other speaks don't

*********** have it.

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The grille dimensions are: 9"x20-7/8" again, with one of the 20-7/8" edges cut at a 45 degree angle.

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I'm guessing all four are the same size? The cut out seems to leave a 1" or 1-1/2" frame... is this correct?

More to come...

Rob

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************* I'm thinking to make that frame a little thinner, it blocks the

************* horn opening.

This blockquote thing is weird......

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Your CAD drawings are really nice. Are you using AutoCad?

I'm looking to do the joint between the angled sides of the doghouse and the front center piece a little differently. I don't want any plywood edges showing so I'll miter the sides of the front center piece and the doghouse front edge to meet clean.

I might use Masonite for the grill frames, might need a little stiffener on the back though.

Again, thanks for your work and time.

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Rob, you're correct on the 3"x13" throat opening slot.

I also assume that the splitting wedge is the same as the La Scala that is 2-1/4" wide x 13.

A couple notes: the 8" wide front piece is set back from the front edge by 3/8" rather than it being flush. This will shorten the dog-house side walls alittle, too.

Ed would be the only one to be able to explain the baffle board/doghouse joint configuration. Yours shows the baffle as being the 90 deg. edges, and the other version from shows that the sides of the doghouse go all the way to the horn baffles. Your's would be easier to build, and I would think that it is probably true to the Klipsch approach, however, the flat baffle board sides as you describe (the plywood edges) would be seen in an unpainted version (Klipsch paints the interior horn sections). This is causing me a dilema...

Other than that, it's looking GREAT! Again, thank you for your time and work on this, it's a great help.

DM2.gif

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Here you go another update, with some corrections.

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On 8/9/2004 1:40:12 PM D-MAN wrote:

Ed would be the only one to be able to explain the baffle board/doghouse joint configuration. Yours shows the baffle as being the 90 deg. edges, and the other version from shows that the sides of the doghouse go all the way to the horn baffles. Your's would be easier to build, and I would think that it is probably true to the Klipsch approach...

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Actually I wasn't sure about the rear one myself (the front one shows up in the pictures as 90deg). The Lascala plans show it's at 90deg so I figured the Belle must be similar and they are probably more accurate than the hand sketches. Anyone could confirm?

Also...

· I'm having problems drawing the grills as I'm not sure of their positioning. The way I figure it is one grill must lean right up on the doghouse and therefore they will not be symetrical to each other. The one I drew is centred in the opening and note how it doesn't follow the angled wall?

· I also noticed the hole for the access panel doesn't follow the angle of the doghouse either if it's 14-5/8", 5-3/8, 5" (angled sides), and 9". Is this correct? Or is my doghouse wrong? I showed the internal volume with the dashed lines.

· To answer the question of how the top front grill is attached, well it's sides are about 1-1/2" in thickness therefore it is thick enough to catch the two vertical 3/4" nailers attached to the sides of the top section. It is screwed through these (see Cut A)

Any other errors / omissions? Thanks for your input...

Rob

post-11489-1381925598807_thumb.jpg

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I feel like I'm nit-picking your efforts, and your doing all the work. Oh, well... What the heck!

Here's another; I figured the space between the end of the baffle board and the side wall to be 3" in keeping with the front baffle horn(s) width. Otherwise it will constrict the horn channel. This is fine for accentuating midrange, but bad for bass notes. The 90 deg. corners should be 3" both directions, IMO. I am guessing here. If so, then that would change the dimensions of the baffle board and channel baffle pieces. I figure 11-1/4" each side, vs. the 11-1/2" that is currently shown. Also, the angles change on the doghouse because of this...

Guys, do you concur? Can Ed measure this? He would know for sure.

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Rob,

Your drawings are most excellent. Now I see why Klipsch left the sides of the 8" front panel exposed, and why Edward posted that pic of the grill board with a 45 bevel on one side. The 1/2" plywood grill boards all have a 45 on one edge. On the inside grilles these 45 edges meet the blunt side of the front panel. On the outside grille the 45 matchs the inside of the sidewall of the cabinet. The panels meet at a 90 in back. This way, all the grill panels are identical and interchangeable. 3/4 x 3/4 glue blocks with velcro will hold the panels. They will be at 45 angles to the front of the cabinet. This will leave the inside grill floating a little ways on the font, but no big deal.

If a guy does the buildup starting at the bottom panel, then builds the doghouse and attaches the sides, it would be easy to get the exact positioning of the velcro glue blocks, especially if the grilles were built first. :)

Thanks again for taking time to do this. It's beyond my current skills with AutoCAD.

Now I need to re-do my cut sheet drawings to reflect the current stage of reality and I'm good to go.

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Sorry folks, been out of touch for awhile working on a couple of pairs of Heresy's. Is it just me or are those things rather....'screechy'? And man, did they cheapen out on the Heresy 2 (in reference to the H1) or what? Looks the same from the outside but kind of like a Forte 2 on the inside....but the sound is very similar. I have a pair of Forte 2's for mains in the 'TV watching room'. A Klipsch SC1 center channel and a pair of Tannoy studio monitors round out the 'HT' there. When I purchased a 1953 khorn from a dude down the street, I noticed that he had stacks of Heresy and Cornwall cabinets (sorry, no empty Belle cabs!!!) just laying around. I inquired and he stated he didn't know what he was going to do with them, so I dropped it. Then the other day he called and said he was chopping them up to use for firewood and would I want any??? Huh??? Come on!!! Firewood??? So I grabbed a couple of pairs of Heresy cabs before they went into the 'pit' as he described it. He even delivered!! One pair was to replace the rear Tannoy surrounds, the other pair was for the garage. Then I found a single H2 (for center) on epay for $103, hence the comparisons. I had the guts for 2 pairs of heresys (except for the 12" woofers) just laying around from replacing them out of various Belles and Cornwalls. So now I have Heresy's and Fortes....in that role, the Heresy's are ok. Man, I even acquired a pair of 12" K22 Heresy woofers from epay yesterday for get this.....$8.50. Anyway, sorry for the OT but I really love dinking around with these speakers....my wife and daughter call it a 'wierd obsession'.

I'll do the same as before, print out your questions, digest, go home and measure or check or verify, then get back with you hopefully within a day or so.

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Huh? what 'side pieces are you referring to Tom? Yes, there are outer side pieces as well as inner side pieces. The outer side pieces are the ones you see comprising the outside of the Belle bin itself. The inner side pieces make up the side of the doghouse so 'yes' there is a 3" channel around the outside of the doghouse. Didn't mean to confuse anyone, just thought that the LaScala busted open like that would be a good visual of the relationship of the 'ramps', throat opening, etc.....the things I am not good at describing....

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edwardre,

I think Tom is saying the Belle 'doghouse' is actually a trapezoid (four pieces) when looked at from the top. That is the way the drawings are showing it thus far. The LS has five pieces.

BTW, I don't find my HIIs screechy at all. Compare quite well to my JBL 4311s.

Marvel

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Yup...you're both correct. Age is creeping up on me......sorry again for any confusion, it is most certainly trapezoidal in shape.

Marvel - maybe there's something wrong with my H1's? Since I got the cabs then populated with existing components that I had, perhaps I have made a faux pax in the component mix. Here's how I populated the pair I deemed to be 'screetchy'.......first, the xovers are the original Type "E"s. Not the ones with the small caps laying sort of flat, but rather the ones with the large oil filled upright caps. These networks look identical to the Type "B"s I yanked out of a pair of early 70's Cornwalls, only I believe they utilyze a different transformer tap. Very spartan (component wise) in appearance - not much to them. The tweeters are stock K77's from a 1972 Khorn that my dad had 'upgraded' with a mid-80's component upgrade kit from Klipsch. These K77's are the ones with the round magnets, not the flimsy square ones. The mid-horns are K700's, and they are the 'sand cast' looking aluminum ones. About a 1/4" thick. Not the thinwalled stamped looking ones. The mid-driver is the standard K55V, the ones with the push on connector setup. For the woofers, I think the designation is K22-"E" (but maybe "R"?). They have metal colored baskets and magnets, which are round. They are not the black basket units with the round or square magnets, though I just received a pair of those black basket ones yesterday that I think I might try out instead.

Also, what woofers do your JBL's have? I have a handful of JBL 12" woofers that I am thinking I will try out in the 'garage pair' of Heresy's just to tinker. A couple of D123's, a 2212, a 2130 and another one which I forgot the designation of. So far I can't really tell much of a diff from the Klipsch K22's, but they are nice looking speakers......:-)

One thing that made a huge difference in mellowing out the screech factor was putting a Jensen RP302 in place of the K77, but try and find a few of those for under $650/pair.......ha ha ha

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I don't even know what the model is for the woofer on the JBLs. Not the D series I know. I used to have the specs somewhere. I've never opened the JBL cabinets since I purchased them in 1972. The have a white surface, and clothe surrounds. Free air resonance on the woofer is 22Hz.

I don't know enough about the crossovers on the Heresy models to give you any tips. My son has the earlier models, and there is some difference in the sound, but I am more of a 'oh yeah, that sounds nice.' I sat and listened to music tonight for the first time in a week.

Marvel

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