[quote=Old Guy;1830801]

Sorry about the senior moment...meant 820c
Not a problem


420 is a biflex isn't it?
Yes it is
Quote Originally Posted by Panomaniac View Post
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Here's a nice thread on the 820. Darn, now I want one - er, two.
Altec 820A Corner horn??
I actually talked to him about those speakers (Dylanl) I asked him if he wanted to sell them but he said he already sold them.:khan: That was a depressing evening.He also said that he thought they were bass shy even though they have dual 803's cabinets internal volume is too small.They are beautiful speakers.I wonder if they would work for me by enlarging the cab some Hmmm.

[quote=GM;1830812]
You're welcome! Ah well, divided by a common language. You don't need to be at mine or anybody else's knowledge level, just when asking for help, the more info the better, especially WRT any size/budget/SAF limitations and of course ask as many Qs as you need to keep from being confused as it can save more time than not.
Thank You for your understanding I appreciate that.:2thumbsup:
Speaking of 'confusion', I just noticed that I didn't complete my now defunct first draft in that I didn't finish the cab gross Vb calculation, so I was wrong, the triangular MLTLs are only ~6 ft^3 gross, so too small for a 416 to go low without significant room gain.
But you caught it that's all that matters.
This begs the Q of how well is your room/house constructed? If it's anything like my old WWII G.I. tract home there's not much gain at all and actually is a bass trap below ~16 Hz.
My house is an older house pre WW II I think it was built around 1928 but is built well the walls are a real thick plaster and it is like concrete with hardwood floors and some carpeting.
Regardless, any shorter than a ~96" total height then means the speakers must protrude into the room even more than the theoretical 8.5" o.d. high SQ limit to get back to the ~11.5 ft^3 that's theoretically required.


At 70", the MTM is marginal since this puts the 511 centered at 35" which is a bit low for an average seated ear height, so any lower and it's not viable for best SQ unless ya'll sit really low/laid back.
Yes I measured my listening area and in a few spots couch,chair and optimal height of horn should be 38"-42"
Anyway, the smallest practical horn cab is 11", so with only a 29.5" o.d. woofer cab height there's not going to be hardly any extra vent acoustic damping, so of course any shorter means none for all intent and purpose.


Again, in a MTM, offsetting the woofers, horn with the ST beside the horn and outside wall seems the best compromise. Putting the tweeter between the top woofer and horn will create an oddball lobing pattern/polar response that's shifted up slightly from the horn, though I've no clue how audible it may be, but my SWAG is that over time it will rub you the wrong way on music you're familiar with.

OK, regardless of whether you use an over/under or MTM, with a 70" total height, each woofer cab has ~8.5778 ft^3 gross with including the 8.5" extension to work with, so call it ~8 ft^3 net. Using published specs and tuned to Fs, this yields a ~50 Hz F3 in half space, so in theory it would be ~42 Hz in a corner, though there's enough efficiency to digitally EQ ~flat in-room to a lower F3 if desired if you have enough clean power on tap.
8.3 ft is the same as a model 19 cabinet isn't it.That gets down to 30 Hz. What I would like to get is 30 Hz but I could live with 35 Hz I don't think I would be happy with 42 Hz as I'm kinda used to 30 Hz as I have been listening to my 19's for awhile now.What other options would I have.Power is not a problem.I have plenty of power.I hardly ever need more than 1/3 of it.Thanks GM Stay Well !!!