[S Clark]

My 15" woofer, the 416 16Z, doesn't even go that  low.  If I want anything below 50Hz, I use a sub.   I could probably get the  magnet "recharged" by Great Plains Audio, but it's fine for what it does.   

[Zuman]

Back in the late '70s/early '80s I ran the entertainment department of a theme park. Sound reinforcement was only just beginning to become based on real science and engineering, and I had difficulty getting budget approval for the equipment we really needed.
Fortunately, I had a small team of part-time, passionate college students and recent grads who were both knowledgeable and also really enjoyed making the most of what we could get, which was often used gear.
Our main stage featured four A7s, and we had great success upgrading them with TAD TD-2001s and TD-4001s for the highs.  Those TADs were just amazing at the time...nothing else came close.
We also had a large indoor dance floor that featured either 8 or 10 A7s (I don't remember which), lined up along the left and right perimeter of the floor, facing inward towards the center. It was, uh, "immersive."
Many bands that came to play at either the outdoor stage or the dance hall were skeptical when they first saw the A7s. They quickly realized, however, that the fidelity of our systems far outweighed what they were used to.

[Jon L]

Dang room bass node.  Moving the listening chair 3 feet hits a nasty bass null, and there is not much room to move the speakers instead.  Bass DSP correction can only partially mitigate this, so my optimal listening seat may not end up at triangle top between the two speakers 

[FullRangeMan]

If you want increase the bass add some carwood blanket 15 or 20 mm inside the enclosure, the 5 or 10mm dont works.
What stuffing you have now ?

[viggen]

Dang room bass node.  Moving the listening chair 3 feet hits a nasty bass null, and there is not much room to move the speakers instead.  Bass DSP correction can only partially mitigate this, so my optimal listening seat may not end up at triangle top between the two speakers 

two upgrades i've been pining is either move from 804 to 802 compression horn in the carmel or replace carmel with A7 Magnificent like the one in the jeff day articles:
https://jeffsplace.positive-feedback.com/overview-update-the-duelund-altec-project/

i guess the 15" woofer is much harder to tame than 2 12" woofers.  i have absolutely no issue with bass that i am aware of.  i do use a 15" velodyne uld once in a while.

guess i will scratch the A7 and just opt for the compression horn upgrade. oh also have thought about upgrading the xo.  but.. lazy.

[Jon L]

So I replaced the Aiyima A20 with FM30/829B.  For replacing 100+ watts of class D power with 4 watts of single-ended tetrode, the difference was not startlingly large.  A casual listener who walked out and back into the room probably wouldn't even suspect an amp change. 

Case for Aiyima A20

More control and hammer-like bass dynamics  For playing electronica in party situation, Aiyima for sure. 
Probably more transparent to the source from sound perspective and likely more minute details in recordings are audible. 
Tonality and solidity of music are outstanding yet neutral.  I would have no regrets listening to the Altec A7 and Aiyima A20 combination for musical enjoyment at any time.

*These results apply when using battery power for A20

Case for 829B/FM30 tube

Reproduction of acoustic bass, actual drums, etc is exemplary with texture, tone and natural ease.  Very deep electronic bass is not as impressive but still listenable. 

If Aiyima was more transparent to the sound, 829B is more transparent to the emotion of the music.  Just a little more human and familiar to the soul. 

While minute details are revealed easier by Aiyima, 829B tube has a way of textures just melting and floating into the atmosphere, into a more "wet," acoustically alive soundscape.  This is probably due to the single-ended even-order harmonics gilding the lily, but the net effect is beautiful and immersive.  This is why you pay the money for good tube gear. 

I could live with either Aiyima or 829B extremely happily, and in fact, I plan to swap them here and there for fun as time goes by.