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Advice re cutting LaScala doghouse angles


longdrive03

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2 hours ago, longdrive03 said:

Andy,

Outstanding post and pics.

Now could you come cut these for me!!!!??

This helps tremendously and I now get what you explained previously - duh

Very efficient jig. 

I believe in taking time with jigs,  and always DO spend lots of time making sure my jigs are good to go...that way I can get very many uses out of them over the years. I even have jigs for making the miter cuts on the wing parts, and they are designed specifically for the particular 10" miter saw I use just for that.

 

Just wondering...how did you take into account the changes in length for the rear two initial flares of the bifurcated bass horn Lenses?...while using over-thickness-dimensioned panels in the doghouse?

 

Also, are you having to build the cabinet to where it is DEEPER from the mouth to the inside of the rear panel to make up for the extra length going forward of the doghouse, itself?  It appears that your side panels and upper and lower panels that wrap around the doghouse will need to be (so far) about +3/4"  deeper, based upon the pics you have been posting up to now.

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I haven't got to the back piece with the flares yet.  Still concentrating on the doghouse since its the hardest part.  Will study more but off the top of my head I will need to bring the flares out to just short of the edge of the  motorboard (17.5" now -- 15.5" motorboard and 2 x 1" dog sides.  Do you usually stop the flares just inside the edge of the dog sides so they are not visible?

 

Do you see any reason that the depth of the cabinet should increase from rear panel to tip of the dog roof?  The motorboard (12) is set between the two dog sides (4) so that will take up 1/4" more of the space inside the cabinet but won't cause the roof tip to extend farther unless I'm missing something (which can happen) Using the 1" dog roof pieces (5) will also take up some interior volume.  Do you think I should lengthen the dog roof panels (and change the corresponding angles) to bring the roof joint farther out from the back? 

 

The side panels will need to be long by at least 1/4" because the mid horn baffle is 1" thick and the rear is 1" thick and the sides overlap the rear.  I have overcut the side panels so I can trim to final width.

 

Still not 100% sold on 1" ply on dog roof (piece 5) if I find out tonight the woofer access isn't big enough and can't be modified.

 

Any thoughts appreciated.   Thanks.

 

Here's a pic of the dog sides and motorboard that is 17.5" wide x 7.5".  I have expanded the width of the inner  bass bin dimension to 23 5/8" .

IMG_6506.JPG

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Keep in mind that the outside of the doghouse is ACTUALLY each side of a horn lens, so that horn lens dimensioning needs to remain constant to the original dimensions for the LaScala.  As for the wings on the rear of the doghouse, they are ALSO something which needs to remain constant, since they dictate the beginning flare-rate to either side.  As for the front to rear side dimensions (including the bottom and top panels of the bass bin), the 1" material you used will have the point of the doghouse moved forward around an additional distance of at a minimum 3/4" (since you ALSO used 1" material for the motorboard, which ALSO pushes the doghouse roof point forward even further).

 

Me?  I would stay true to all the dimensioning of the horn lenses...but now you have the sides of the back of the doghouse (motorboard) pushed further each side off the centerline, due to adding the width to the motorboard itself and additionally using thicker stock back there on each side of the doghouse...so you are looking at a narrowing of the horn lenses either side of the doghouse, which is basically a "volume of air moved" issue.  As for the wings between the rear panel and the motorboard, I am no engineer, but I would PRESUME that particular flare rate should remain the same as on the original design...but with the added width of the rear of the doghouse, that is like stretching a non-flared choke-point for "volume of air moved", then continuing that choke along the outside of the doghouse sides until the flare begins again...at the point in which the doghouse roof panels come into play for the final flare rate.

 

Make sense?

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As far as simulations in HornResponse changing the flare has very minor effects on frequency response. With the driver filling the with of the doghouse thicker doghouse it will increase the horn path a little. Simulations does not tell the whole story but still.

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Andy, thanks for visiting last night by phone - it was very helpful on many levels.

 

Current status is I have one dog roof glued at the toe.  Attached pic shows dry fit of roof to sides and motorboard.  No glue to sides yet.  I'm pleased with the fit.

 

Tonight I hope to get the roof glued to the sides and nails/screws from inside at roof joint with sides to pull it tight. and then finish routing out the woofer entry hole and maybe glue up some veneer on the inside of the  top of the bass chamber.

 

I confirmed that the Crites 15 cast woofer will fit into the doghouse (kinda important !)

IMG_6518.JPG

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1 hour ago, longdrive03 said:

Andy, thanks for visiting last night by phone - it was very helpful on many levels.

Not intending to hi-jack your thread, but you asked last night, so here are some of the detail pics I promised to show you:

 

Top pic:  Shows the mitered in hi-freq motorboard, with vertical center book-match.

 

Second pic down:  The pair with grilles attached using magnets, even though I built these with no intent of using any grilles.

 

Third pic down:  Look closely to the build details...

      Bass bin top panel was dadoed into side panels, which is not easily seen.

      What you CAN see is how the rabbeted joinery for the rear bass bin panel and the upper reinforcing horizontal piece played out, but what you CANNOT see is the rabbeted joinery for the bottoms of the sides to the bottom panel of the bass bin.

      You can also see that after I got everything glued clamped-up, I used diagonally-split glue blocks INSIDE the HF section wherever a miter joint was used for the construction...to reinforce the clamp-hold until the glue had set-up.  I also used those blocks inside the sides to ensure the dado joinery for the top panel of the bass bin into the side panels remained stable until the glue set-up.

 

Fourth pic down: Detail showing the miter of the HF motorboard to the cabinet top panel.

 

All of the rabbet and dado joints actually stiffened up the cabinet quite a bit...especially so in the sides to the bass bin.

 

Hope this somewhat clarifies what we talked about on the phone last night!

 

solo oak LaScala no grill  note book match detail.jpg

pair of oak LaScalas.jpg

LaScala rear showing assembly details and guardcat option.jpg

oak LaScala HF front and top joint detail.jpg

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43 minutes ago, longdrive03 said:

Thanks for the pics Andy.  Speakers look great.  I like the vertical grain on the front top board.  .  I plan on insetting 3/8" neo magnets in the mid/hi front board under the veneer to allow attaching the grill without any velcro or grill guides.

 

These pics were taken at the church where the cabinets ended up about a year or so after they were bought...they had already been moved around a number of times, from different parsonage rooms into the church annex, where the pics were taken...and needed a good wiping down to get dust and stuff off of them but I was in a rush so just took the pics without doing any cleaning of them.  If I was planning for them to have grilles added when I built them, I would have saved time on the build by insetting the HF motorboard, instead of doing the mitering of it...assembly would have been much less time-consuming, too....and the cabinets would have been more aesthetically pleasing  with full mitered face edge veneer instead of what I actually built.

 

Magnets under the veneer are a good idea for the HF section grille attachment.  That way you have the option of having the grilles on or off, without any unsightly magnets or Velcro showing when they are removed.  Unfortunately, I build with pre-veneered plywood, so that is not an option for me...but I have a different idea I will be trying out on my next pair(s).

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Back spasm Friday morning (wonder from what???) slowed me down this weekend.  Weather didn't help 77 saturday afernoon and 17 degrees the next morning.  Got the bottom section done just need the sides, top and front mid horn panel and back brace.  Made a jig to use on K400 and EV77M rear mounting tweeter. Hope to get everything veneered and assembled this week.

 

 

 

IMG_6553.JPG

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On December 13, 2016 at 11:15 AM, HDBRbuilder said:

Not intending to hi-jack your thread, but you asked last night, so here are some of the detail pics I promised to show you:

 

Top pic:  Shows the mitered in hi-freq motorboard, with vertical center book-match.

 

Second pic down:  The pair with grilles attached using magnets, even though I built these with no intent of using any grilles.

 

Third pic down:  Look closely to the build details...

      Bass bin top panel was dadoed into side panels, which is not easily seen.

      What you CAN see is how the rabbeted joinery for the rear bass bin panel and the upper reinforcing horizontal piece played out, but what you CANNOT see is the rabbeted joinery for the bottoms of the sides to the bottom panel of the bass bin.

      You can also see that after I got everything glued clamped-up, I used diagonally-split glue blocks INSIDE the HF section wherever a miter joint was used for the construction...to reinforce the clamp-hold until the glue had set-up.  I also used those blocks inside the sides to ensure the dado joinery for the top panel of the bass bin into the side panels remained stable until the glue set-up.

 

Fourth pic down: Detail showing the miter of the HF motorboard to the cabinet top panel.

 

All of the rabbet and dado joints actually stiffened up the cabinet quite a bit...especially so in the sides to the bass bin.

 

Hope this somewhat clarifies what we talked about on the phone last night!

 

solo oak LaScala no grill  note book match detail.jpg

pair of oak LaScalas.jpg

LaScala rear showing assembly details and guardcat option.jpg

oak LaScala HF front and top joint detail.jpg

 

HDBR - those are the cats meow!!! 

Couldn't help myself!

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  • 2 weeks later...

I've got 3 coats of finish on these now and will get two more on this weekend.  I am gluing the veneer on the inside of the side pieces in the bass bin now.  Pics is a dry fit of the sides showing how they look now.  Hope to get these built this weekend and start on the outside veneer and then front edge solid cherry trim and bottom riser with cherry outer kickboard.

IMG_6662.JPG

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I was really looking forward to starting on my Belle bins during the Christmas break from school, but, I'm sitting in the CCU with my mother as I write. Been a rough year for her and things look dismal. I can build the bins but still thinking I need to solicit longdrive to build me a pair with all that's going on. ;)

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Thanks for the compliment Schu!  I appreciate it.

 

AVGUY sorry to hear about your mom.  Hope she recovers.  

 

I know you were going to build some Belles but didn't know if you had started.  Do you have all the speaker components and xovers for the Belles?  I've got a friend that is looking for two Belle mid horns (K500?).  He is going to buy the Belles I just finished (at least the bass bin) if we can locate a Belle mid horn.  I'm building these LaScalas for him now.

 

Thanks.

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