GM-416-8B MLTL Corner Cabinet

[VolvoHeretic]

Thanks Sri, with 26.5" depth, I get exactly 24.39 cu ft. I just need to know what the volume of the 811B is.

[GM]

I just need to know what the volume of the 811B is.

Fixed previous specs broken link.

http://www.lansingheritage.org/images/altec/plans/1968-enclosure/page04.jpg

GM

[VolvoHeretic]

Fixed previous specs broken link.

http://www.lansingheritage.org/images/altec/plans/1968-enclosure/page04.jpg

GM

Thanks GM. So I have 416-8B = 0.25cf, 811B = 0.19cf, 802-8D = 0.026cf = 0.466cf total components.
Vb = 24.5859cf - 0.466cf = 24.1199cf net. I will recheck my math tomorrow.

[srivenkat]

Thanks GM. So I have 416-8B = 0.25cf, 811B = 0.19cf, 802-8D = 0.026cf = 0.466cf total components.
Vb = 24.5859cf - 0.466cf = 24.1199cf net. I will recheck my math tomorrow.

VolvoHeretic,

Thank you.

Here is the link from GPA spec sheets
416-8B - http://www.greatplainsaudio.com/down...ec%20Sheet.pdf
802-8G - http://www.greatplainsaudio.com/down...ec%20Sheet.pdf

Please note the Vent details from the first post,

from GM
"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. For all I know, having different size holes in each side may work best overall since the room dominates and SET tube amps can be pretty finicky about impedances not ruler flat, but the passive components to flatten a low Fs bass driver's impedance are large, not cheap. "

Any thoughts/inputs on sides tapered box - the rectangular dim came to 58.5HX38.5WX18.5D

Again, great drawings thank you so much for sharing these.

-Sri

[VolvoHeretic]

Sri, here is a simple 22.5 deg. taper 40"x34" compared to GM's original design. The taper projects out into the room quite a bit more. After all of these corner variations, I would have to say that GM's design uses up the least floor space and allows the easiest adjustment and is probably (undoubtedly) the easiest to build (all angles are the same, both sides of the cabinet are the same, and both cabinets are the same).

[srivenkat]

Sri, here is a simple 22.5 deg. taper 40"x34" compared to GM's original design. The taper projects out into the room quite a bit more. After all of these corner variations, I would have to say that GM's design uses up the least floor space and allows the easiest adjustment and is probably (undoubtedly) the easiest to build (all angles are the same, both sides of the cabinet are the same, and both cabinets are the same).

VolvoHeretic,

Thank you. Looks like taper may not be the right option. Few of basic questions,

(1) Your reference to GM's original design is 45 degree version? (I was pretty much set on this one as it was easier to build and I am fine to be slightly away from the sweet spot)
(2) I understood the best option is the curved one which allows the easiest adjustment, please correct me otherwise.
(3) Finally, what's your input on a rectangular one? Simple to build and I can move from corner but use corner traps, etc. Would it be a bad choice?

Please bear with my basic questions. And, thanks a lot again.

-Sri

[VolvoHeretic]

VolvoHeretic,

Thank you. Looks like taper may not be the right option. Few of basic questions,

(1) Your reference to GM's original design is 45 degree version? (I was pretty much set on this one as it was easier to build and I am fine to be slightly away from the sweet spot)
(2) I understood the best option is the curved one which allows the easiest adjustment, please correct me otherwise.
(3) Finally, what's your input on a rectangular one? Simple to build and I can move from corner but use corner traps, etc. Would it be a bad choice?

Please bear with my basic questions. And, thanks a lot again.

-Sri

Hi Sri,
1) Yes GM's original 45 degree design offers the least intrusion into the room as it is rotated (I think).

2) I have worked for a short time in a cabinet shop, so I am biased towards the most complex shape possible. However, if this is your first build, a rectangle will be simplest and the 45 degree next.

3) A plain rectangle will work fine, but in my experience with a similar width room, spaced as wide as I can get them is best for me. I will draw it up and post it so you can see.

Here are my 28"x42" rectangular speakers in my room, I actually have to pull them out into my room so that they line up in an arc with my center channel:

[GM]

Option 1 - Curved Cabinet ? Tough one! I won?t be able to build this myself.

Greets!


Gotten kind of behind and still short of time, so just a ~ quick note........ don't start 'burning' wood yet except to do the baffle since I've more to post WRT the whole curved/tapered/bracing subject and don't forget that the 811 ideally needs to be set back in a recess along with its foam inserts same as the M19's to use its XO, which I didn't see shown.


Trust me, anybody with the ability to use a few basic hand tools can do a curved [ML]TL.


Anyway, thanks all for the great tutorial help, input, for this project and especially for future reference!


GM

[VolvoHeretic]

Does anyone have a 811 exposed that they could measure for me? I know the flange width and height and also the overall length, but I need to know the height of the horn mouth and its width in front of the flange. I have a 511 and tried to scale it down, but I don't trust the dimensions.

[GM]

http://www.lansingheritage.org/images/altec/plans/1968-enclosure/page07.jpg