Presumably it depends on the design of the drivers and enclosures as to how much mechanical damping is there to start with, something designed for a non-zero output impedance won’t need its spade terminals welding with every thud.
All of the discussion so far keeps leading me back to the question - why (if it is so), specify bass drivers that have wildly incompatible amplification needs versus the rest of the drivers in the speakers?
I really do know less than nothing about loudspeaker design, but cannot escape wondering why, if as you inevitably must, you make compromises, why this particularly awkward one?
Obviously Matt’s quest to discover which particular drivers are actually in the boxes continues to grow in relevance…
I hear Jeff Rowland make some pretty decent amps… 
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Don’t really read manuals tbh. I know absolutely everything don’t you know. No manual can teach me anything. Except the one for the coffee machine.
Measuring rooms is nice though, as a starting point.
Massive Pass amps would be good. None of that low powered diy malarkey.
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The answer to every ‘What amp should I buy’ thread, irrespective of budget.
I like reading manuals. Typically, I don’t understand or remember any of it, but that is OK too.
If you were to take a look at some bloke called Allan Soo’s Goto system he runs with Pass Power amps.
Pass amps with decent damping would be dead good imho.
Part of the issue is that high damping factor amps are often not class A, so not that linear at very low levels. This is not great when combined with compression drivers that are very sensitive.
In many ways it’s just more sensible to have separate amps that are designed to work with their respective drivers. Sure, you can get a 200W Pass class A monster, but it’s expensive and only useable three seasons at best! Cheaper and cooler to get a 300W class D and a 2W SET.
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Pffft. Where is your commitment man?
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The amplifier damping factor is only dominant in the case of a directly coupled driver, with active crossover before the the power amp.
With the current setup, damping will be affected by the amp output impedance, cable resistance and crossover resistance (3 chokes in the picture) so the chance of getting it above 25 or so is slim with everything factored in.
Chuck in a bit of NFB 
I’ve tried and liked Cerwin Vega and QSC RMX. Had a few others on loan I’ve forgotten.
Haven’t found D class pro audio amps did the job as well - maybe if you spend enough though:)
These are only for 10Hz to 100Hz on a 6th order X/O though.
Not for general Hifi duty.
I think it is.
Big powerful driver, pushing a 2.4m long, narrow column of air, front push timed to hook up with the backward cone pulse.
That weighs a bit… I did work out how much but can’t remember.
I’ve tried all sorts of amps. All the tube ones I could afford or borrow were pretty hopeless.
10 to 50 damping factor just don’t control.
I don’t have any maths to decree it.
Just using trial and error.
Had really expensive audiophile (what I’ll call full range amps) here.
They were rather embarrassed actually.
Crest fallen audiophile exits stage left:)
Even a lowly Behringer Inuke saw one off:joy:
Just don’t need all that over engineering and beautiful casework. Put the $$$ in to the transformers and silicon and Neutriks:)
They still need to be be well designed and made.
Yeah, I get the limit boxes thing.
You’ve got some investment there in nice Cu X/Os there too.
If that is the constraint, one audiophile amp should do your upper channels and one, or two, for the two bass channels - see, I snuck another amp in there🙂
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ok, so @Jim really needs three amps, and a decent pair of subs:
10 to 80 ish Hz - Lab subs in the two back corners - similar to @keith1962 - with active 6th order Xover and high damping factor power amp
80 ish Hz to 400 ish Hz - the 4 x 15" bass horns - possibly class A SS amp, or maybe big watts valve amp
400 ish Hz upwards - mid and tweeter horns - flea power SE triode amp
for an entry level multi-way horn system
sorted 
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…and you were doing so well 
Most of the guys I know running GPA in scoops or Altec A5 type arrangements aren’t using high damping particularly or class D come to think of it.
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If we are playing the “spend Jim’s money” fantasy league game and heading for PP rather than SE or SS, Robert Koda?
Fuck, I bet he’s chuffed he bought those speakers!
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I am actually Mike, yes. Just need to get the amps and room tailored to suit them. It’s defo sounding a lot better now than when they were first installed, but still some way to go.
It’s a good job I’m retired so have plenty of time on my hands. 
/cunt
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