A7's with subs?

Hi Guys,
Was just wondering if anyone has recently heard a set of A7's with good subwoofers in a live sound situation? I heard lots of A7's in the 70's and into the 80's, but live sound was a lot different then. mostly just vocals in the PA and guitar amps were run unmiked, and LOUD![talking about club sound, not the big guys like showco and such.] I just sold a set of 1204's to a really nice group of players that were going to use them to replace their A7's.Basically their A7's were beat, and needed replacing. While talking, the idea came up about using a good set of newer designed subs with a set of A7's for really good sound and I am wondering if anyone has heard or experimented with such? While I am sure they would be no fun to move around, they might just sound really good together.
just a thought,
regards,
scott in nc

There are posts here about sticking an 18", usually a JBL 2241/2, into a sealed off section of an 828 cab, thus leaving the ALtec horn for the mid bass and the 18 for the deep end.

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Originally Posted by magnarc

There are posts here about sticking an 18", usually a JBL 2241/2, into a sealed off section of an 828 cab, thus leaving the ALtec horn for the mid bass and the 18 for the deep end.

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Actually, the "recipe" calls for 2245. I was not impressed with the pair that i heard a couple years ago. IMO, the end result is two pairs of woofers of which neither is in an ideal box, and a ruined pair of 825/828 cabinets. This is just my .02, others describe the result as "pure bliss".

OTOH A7 and an external sub can sound great. I had best results with xover in the 80-110 Hz range.

For me, too big to move, live I would use 816 and subs instead. Permanent system is a different story. The 816 would probably be happier at 100 Hz, it's rolling by 80.

Interesting ideas.

Are we talking about the standard A7 with its big port and high tuning? In that trim it does not reach down very far. I can certainly see a sub with it.

But I'm with OG on the portable system, too big and heavy. Use a sub with a smaller "mid" cabinet. No need for the big A7 box if you have a fill below it.

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Originally Posted by bowtie427ss

Actually, the "recipe" calls for 2245.

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The disparity is probably in the setup since it's not an intrinsically bad pairing, though my original that spawned them used a 1st. gen. 411, a 'match made in heaven' to all that auditioned them including a couple of folks from the Altec distributor.

Regardless, I did a few A7/sub PA setups for 'garage'/DJ apps by chopping off the reflex section of the cab, running the rear chamber sealed at ~1.5 ft^3 IIRC with several inexpensive 15" woofers in TQWT pipes to keep price down, efficiency up. XO was from the June '70 issue of Popular Electronics with a claimed 100 Hz/3rd order mono summing design tapped off the main amp to feed the sub amp. [AKA PLLXO these days]

Don't recall ever doing any measurements, but never got any complaints about their performance when they weren't overdriving them to destruction, so guess they otherwise performed well enough once EQ'd at the mixer.

GM

in fact.. if you look at the post 'bf titan 39' here on the board... we had to run a pair of very effecient subs in a live sound setting per side to get the effecientcy up. we found that running just a regular sub with the a-5's in an active thre way setup, that you couldnt tell the subs were running. this is with the 75 sq in vent opening on the a-5's. todays music in the clubs in very bass oriented..gets the girls dancing and the boys buying drinks. we also cross the subs out at just over the kick drum, which is brutal in a live setting

There is a thread at LH of a guy in Paris,France that mounted a 18" sub in a pair of A7's.Here are the pictures.



http://www.hostboard.com/forums/hbmc...2011/04/38.jpg

http://www.hostboard.com/forums/hbmc...2011/04/39.jpg

Now that is novel.

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Originally Posted by Altec Best

There is a thread at LH of a guy in Paris,France that mounted a 18" sub in a pair of A7's.Here are the pictures.

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Thanks for pointing that out!

The dialog is particularly entertaining;

http://www.audioheritage.org/vbullet...body-done-this

Those sure are green! (see the last page).

I've often thought about a similar rig, but am pretty happy now with the bass using only a 416 per side.

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Originally Posted by bfish

The dialog is particularly entertaining;

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Yeah, the 'blind leading the blind' to my way of thinking............. Anyway, for those that believe a vent of any tuning is superior performing to a properly designed/implemented (mid) woofer/compression horn A7 conversion, then to allow it 'to be all it can be' at least use multiple passive radiators [PRs] same as Olson did on his LC-9A 'A7' variant to tune it except mount them on opposing sides to ~ cancel out their high excursion rocking vibrations.

GM

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Originally Posted by Panomaniac

Those sure are green! (see the last page).

I've often thought about a similar rig, but am pretty happy now with the bass using only a 416 per side.

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Wow--that is a fluorescent green! Well, on the "bright" side, there's nothing wrong with those cabs/speakers that a good pair of sunglasses and earplugs won't fix!:doh:

Yeah, I like green but I don't think I could take those for long.

My guess is that the section of the box used is too small for the 18". But that's just a guess. It still ought to add some good grunt.

Dunno, don't care, it's the concept they're trashing that I take exception to........

GM

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Originally Posted by GM

... it's the concept they're trashing....

GM

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One-track decks playing an echo loop...

When they get a load of the dual 18s I'm stuffing in mine, they'll need a bevy of exorcists to stop the head-spinning and projectile vomiting.

Added
Now I wanna paint mine... I dunno... maybe orange.

Bfish, tell us more.

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Originally Posted by mah

Bfish, tell us more.

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The best part of an 825/828 box is the front horn. From there it goes downhill. The output starts to roll off aound 180Hz where the horn unloads. Doesn't matter if you tune the reflex to 60, 40, 20, or even 10, the reflex output is way less than the horn, and being forced to play that low with little acoustic load soon compromises an underhung 15 with excursion limits.

Dividing the box fixes those issues. There's less than 2 cu/ft for the 15 (assuming full-width baffle sealing off flare volume), which, when fine-tuned, matches the reactive load of the horn, raises Fb, limits the 15 to just what it does best (in this app), and lets it do a lot more of it. The ~7.6 cu/ft left below just happens to be "perfect" for a 2245 (and several other 18s). Biamp the combo and bring the LF up to where it needs to be; at the same output level as the front horn. No brainer.

I'm using 2 each simply because I had them, but have no room for the 4 external 7ft boxes they'd be ideal in. Sure, they won't be flat to 27 Hz in that volume like one would (BR), but they will be sealed so I can EQ it flat wherever they are. I just hope they can keep up...

The project went on hold some time ago because I got frustrated being unable to get a satisfactory oak finish on the extra layer of ply I skinned them with (can't veneer with the 3/4 round edges and rounded corners). Screw that. Now I'm just p'd off enough to paint over the stain and get them in action before I get too old & frail to move them around.

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Originally Posted by GM

Dunno, don't care, it's the concept they're trashing that I take exception to........

GM

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That was my feeling about it as well.