Vas is huge at 317 liters. This means a large box to start with, but the bigger the better. Very low Fs of 19Hz, which is fine. Large dia. VC and long linear throw of 33mm.
None of the various alignments give a spec for ripple in the passband. For a 2nd order alignment, you really want #3 which means a 6 cu. ft box in your living room, stuffed with 4 pounds of fluff....that's alot of fluff....
The dB figure as quoted is only attained when 750W is applied! In HT though, we don't listen to sine waves as music/dialogue/tracks aren't at all the same. Also note the "assumed" dB gain levels that are figured into the results. Thus these figures need to be taken with half-a-grain of salt: What size cabin? What shape room? No spec for that.
In the vented alignments, the required box volume is very large indeed as is the multiple vent dia. and length. And remember, when using a driver of this size in any alignment sealed or vented, the box volume must be increased to account for the room taken up by both the driver and vent volume. Volume must also be accounted for any lost due to bracing as well. Due to their higher order, they are more easily mis-aligned and as such, need to be carefully tuned in order to obtain the desired results. This means measuring equipment.
A good book to begin with is Ray Alden's Speaker Building 201. May still be in print or you can borrow it from a library. If your local library doesn't have it, ask them to borrow it from another library that does. Libraries do this all the time.
Vas is huge at 317 liters. This means a large box to start with, but the bigger the better. Very low Fs of 19Hz, which is fine. Large dia. VC and long linear throw of 33mm.
None of the various alignments give a spec for ripple in the passband. For a 2nd order alignment, you really want #3 which means a 6 cu. ft box in your living room, stuffed with 4 pounds of fluff....that's alot of fluff....
The dB figure as quoted is only attained when 750W is applied! In HT though, we don't listen to sine waves as music/dialogue/tracks aren't at all the same. Also note the "assumed" dB gain levels that are figured into the results. Thus these figures need to be taken with half-a-grain of salt: What size cabin? What shape room? No spec for that.
In the vented alignments, the required box volume is very large indeed as is the multiple vent dia. and length. And remember, when using a driver of this size in any alignment sealed or vented, the box volume must be increased to account for the room taken up by both the driver and vent volume. Volume must also be accounted for any lost due to bracing as well. Due to their higher order, they are more easily mis-aligned and as such, need to be carefully tuned in order to obtain the desired results. This means measuring equipment.
A good book to begin with is Ray Alden's Speaker Building 201. May still be in print or you can borrow it from a library. If your local library doesn't have it, ask them to borrow it from another library that does. Libraries do this all the time.
I think you're making the mistake of getting a big amp due to the drivers 750W max power rating. That's not necessary, nor recommended, even by Adire. He clearly states so. 100W/ch is fine. Save your money.
Finally, the amp doesn't "push" power into the driver. The later is the load and it pulls current as needed from the output stage, which is essentially a constant voltage power source. The freq-dependant impedance of the load is constantly changing, therefore so is the amount of current draw.
A sub only operates over a few octaves anyway, from 20 - 80Hz is two octaves. At higher freq. it needs to be rolled off at either 12 or 18 dB/octave. That's the filters job. Likewise the loudspeakers are spared having to reproduce these two lowest octaves, which greatly reduces their distorsion and improves their power handling abilities.
I generally err on the side of having too much rather than too little in terms of driving power. I listen to loud, often bass-heavy music, and as such, have found the limits of a few different amps, including my present one for driving the sub. I had to dial out some of the gain in my Denon receiver for the sub in order to stop it from going thermal.
I've used a PA poweramp to drive my sub with a similar power rating to that Crown unit (Yorkville), but the heat it put off, as well as the inability to elegantly trigger its power on/off, caused me to go with something that integrated into my system a bit better.
I'm currently using a SpeakerCraft SC2-100, which has remote trigger and an output of 400W RMS bridged @ 8ohms, or 220W/channel unbridged at 4Ohms.
I think you're making the mistake of getting a big amp due to the drivers 750W max power rating. That's not necessary, nor recommended, even by Adire. He clearly states so. 100W/ch is fine. Save your money.
Finally, the amp doesn't "push" power into the driver. The later is the load and it pulls current as needed from the output stage, which is essentially a constant voltage power source. The freq-dependant impedance of the load is constantly changing, therefore so is the amount of current draw.
A sub only operates over a few octaves anyway, from 20 - 80Hz is two octaves. At higher freq. it needs to be rolled off at either 12 or 18 dB/octave. That's the filters job. Likewise the loudspeakers are spared having to reproduce these two lowest octaves, which greatly reduces their distorsion and improves their power handling abilities.
BTW, my aunt had 4x (IIRC) McIntosh power amps that came out of a huge home theatre (cinema) I think they were "rated" for 150W RMS. they had to weigh similar to your Sherwood. I always thought they would have worked well driving a sub.
The issue with my setup, not to go off on a tangent, is I'm using a car audio sub with an obscene power handling rating. My buddy won the IASCA Nationals with this sub in a Mercury Cougar years back. Two of them, in another box, he won SQ. He had a couple of huge amps bridged down to 0.5ohms feeding the pair of them. I remember one of the amps blowing up and it was rather impressive, LOL! I think that setup was 4K watts? Might have been more. Anyways, the sub is ridiculous, and so I've sort of settled on just feeding it with something adequate for my listening needs rather than trying to match its rating. I've thus far concluded that the SpeakerCraft isn't quite big enough, but is the right "style". If you've got any recommendations on something that can handle 4ohms bridged, I'm all ears 
Edit: Would definitely be interested in those calculations 
