Quote Originally Posted by GM View Post
Greets!


Bummer about your family. Hope your mom's getting [a lot] better medical care than me and at least stable enough for ya'll to be able to somewhat enjoy this beginning of the holiday season.


Anyway, this project has moved far afield from the original and either I forgot stuff in my design considerations/trade-offs or I guess chose to selectively ignore them to minimize the acoustic trade-offs since I want a ~all encompassing tutorial to point to in the future.


The vents were to be on the lower front sides like Billfort's and for the dual driver/511 combo I chose to put the horn in the cab since it would be too far away from the woofers with the desired XO [point] and recessed ~like the M19's, which has been already worked out for us by Heathkit [Altec?] many decades ago.


Not much tech info per se, but I did calculate it close enough way back when using the sales brochure and peering through the grillcloth of one, though couldn't find it it in the relatively few notes I still have available and can't recall ATM if I actually built one, but these should suffice:

http://www.heathkit-museum.com/hifi/hvmhh-1-c.shtml

https://www.google.com/search?q=heathkit+legato&rlz=1C1AVNG_enUS675US675& espv=2&biw=1044&bih=514&tbm=isch&tbo=u&source=univ &sa=X&ved=0ahUKEwismeSD063QAhUCOSYKHRM0BHMQsAQIIQ& dpr=1.1

http://i40.tinypic.com/2vvkilh.jpg

https://s-media-cache-ak0.pinimg.com/236x/7b/82/f4/7b82f49c59a0ecb3539c6ce3c7abf2ac.jpg

If a top mounted horn is used, then the woofers ideally need to be at the extreme top as the Lp is too close for good summation, though the woofer's output will theoretically sound audibly different in an A/B comparison to the Legato variant.


More to come as time permits.........and hope ya'll have an enjoyable, filling, profitable [if applicable] holiday weekend if I don't make it back before then.


GM

GM,

Thanks for the details. I was under the impression that single woofer configuration will have the horn in the cab but the dual will have it on top of the cab. For both, I can have the horn (511 and 811) inside the cab.
For 811B horn (total height - 8-5/8") - you have "horn down - 4.75"
So, I guess for 511B (total height - 10-5/8") - I should add 2" down based on its height. This requires woofers offset to go relatively 2" down?

For Port - you have given the details....
"Vent = [1] 5" dia. x panel thickness [0.75" assumed]/side for ~25 Hz Fs or can both be on one side horizontally.
Recommend using a removable baffle to try up to [1] 9" dia. vent hole/side for more typical Altec tuning or just start big and add smaller hole discs till it sounds right."

Thanks and have a great holiday weekend.

-Sri

- - - Updated - - -

Quote Originally Posted by VolvoHeretic View Post
Sri, thanks for the kind words of encouragement. My 84 year old mother-in-law is in a drug induced coma and a ventilator, but she needs to be weaned off of it and start breathing on her own. It is still touch and go and she is developing congestive heart failure which is fluid surrounding the heart.

Anyway, it appears that pine hand railing comes in 1.5" diameter and the 4x4 ply plates will have that same size hole drilled in them so the railing is the full inside box height and the plates slide over it and will act like a large gusset and increase the gluing surface area from 1.75 to 16 sq in plus the .75" depth.

I envision using 2x2's cut diagonally into 1.5x1.5 triangles to also give a large gluing surface area and I would screw the removable panels to them with 1.5" #12 screws @4"O.C. and I suppose a highly contrasting screw hole plug could look acceptable (like cherry plugs on a light birch finish) and in that case, you could go back to the original drawing with just the areas for the speaker(s) and ports doubled up.

I still don't know where to place the ports and I don't know what affect having a stepped thickness near the ports will have on their function. If you could router a step into the port board outer diameter, you could leave that area just a single thickness and just change out different circles with various diameter ports.

Let me do some more drawing.

James

James,
Very sorry to hear about the mom's situation. Hope things get better for you and your family.

-Sri