Progress on 210 restoration project

[dhook17322]

Have three questions I need some help on:
1. I have 4 515's, 3 B's, and an E that has to be reconed because of rubbing coil. Would it make sense to recone all 4 like 515G's? Probably the three B's should have the magnet strength checked anyway. Jim Dickinsen wrote in his article he prefers G's for 210's, yet Bill at GPA seems to like B's. Any preferences?
2. The horns I have are 1003's with 291 drivers rebuilt at GPA as 288C's. Any preferences on crossover point - will they work down to 300 or best stick with 500Hz?
3. Last question on subs: I have two 411's per Jim's advice. I had hoped to find a pair of 3182's, but they are very scarce. Was also looking at North Creek's big 18, but they are discontinuing it - they can't get motors! This sort of narrows the choices to maybe an Adire 18". Prefering pipe organ music, I want the subs to work well down past 20HZ. Any help or reccomendations would be really appreciated.

[joejoe723]

HI GM

Do really want to sell your 515b? How much you want? Please send an email to me.

Thanks

[GM]

I guess my attempt at humor didn't translate well. I have no intention of ever selling them, they are actually willed to someone when I die and he probably won't ever sell them either.

BTW, I just noticed your query WRT adding a sub to an 825/828 cab on the multi-cell thread below.

GM

[dhook17322]

Thanks much for your advice. I plan to bi-amp the setup, actually I have a Rane 6 channel amp for the task of driving the 210's and the two subs. Sticking with the B's makes sense - adding dual Maelstroms to the 210 cabs would make an incredible set of speakers, a very interesting idea.

[djnagle]

GM, you mentioned adding a sub to an A7 cab. I want to do this at some point in time to mine and I have many post saved as to the process of doing this. All the post say to use the 18" jbl 2245. Do you or others know which Eminance (SP) would work instead of the 2245?

[GM]

Even if you recone them as 'G's, they won't 'sound' quite like them so best in your case to either get 'G's or get another 'B'. I've had 210s with 'B's and while I had to sell the cabs awhile back, anyone wants my 'B's will have to pry them from my cold, dead, hands.

For HIFI, 1003s can be XO'd and EQ'd to 300Hz, but for high power, 500Hz is best.

Subs are a mixed bag. For best performance you either need a horn sub stack (duh!) or a ServoDrive Contrabass/chnl to easily match the well damped/low distortion performance of an optimized 210. After these, multiple relatively low Q drivers digitally EQ'd flat in-room are best.

With the driver area blocked off to form a compression chamber there's enough cab Vb left for dual Maelstroms in a bipole layout tuned to 16Hz. These will put those 64ft organ pipes in your room, or outdoors for that matter.

Of course considerable bracing/damping is required and due to efficiency differences need to be bi-amped.

GM

[GM]

At a glance, nothing they have looks worth the effort since I didn't see an HE one with a low enough Fs, but I don't keep up with what all is available anymore and don't have time to do an in-depth search so YMMV.

GM

[djnagle]

GM, Thank you anyway. I am not in a big rush to do this so I will keep my ears to the ground for a pair of 2245s. P.S. I expect quotes this week for the CMM and CNC on the wood 511 and will keep you posted.

[dhook17322]

GM mentioned the sub driver I have been looking at - the Adire Maelstrom which has an Fs of 20Hz.
They also give vented cabinet drawings for this driver, one of the ported cabs gives a response +/_3db to 10Hz. They seem to cater to DIY enthusiasts somewhat like Altec used to - refreshing development to me. Maelstrom vented enclosures:
http://www.adireaudio.com/tech_paper...strom_apps.htm

PARAM VALUE
Re 3.4 ohms
Le 3.5 mH
Qms 19.11
Mms 245 grams
Qes 0.29
Cms 0.24 mm/N
Qts 0.28
Rms 1.76 N*s/m
Fs 20 Hz
Sd 1180 cm^2
Vas 460 liters
BL 19.8
Xmax 13.0 mm one way
EBP 69
SPL 92.9 dB @ 1W/1m
No 1.22%
Pmax 550W per voice coil; 1000W total to the driver
NOTE: Power rating is thermal only! It is NOT a power requirement; typically you get full output with significantly less power than the rating. PRICE $299

Note that all specs are taken with the voice coils in parallel. This unit is capable of an honest 1 kW of power handling, thanks to its 3" diameter voice coil.

[GM]

Unfortunately the 825/828 doesn't have enough space for the long vent the Maelstrom requires so while the driver will work, a pair of PRs are required to tune it properly. This will drive the cost up pretty high and require a ~16" hole to be cut in both sides.

GM