Beyond the Ariel

[SunRa]

I hope I'm not troubeling too much with all these driver proposals but it seems to me that 12ND710 might have the advantage of smaller distorsions than the 12NDA520 due to the DDR technology implemented in the first one. The FR plot seems the same, maybe slighty better in the HF. On the other hand the impendance curve isn't as flat as the the 12NDA520 but close. Unfortunately this is just a guess due to the fact that there are no measurements for this DDR technology so it might be just marketing.

[Russell Dawkins]

Originally posted by JohnL

My question is, has anyone contemplated a really large woofer for bass? Something like this perhaps. My thoughts are that a decent 10"-12" that could hold itself together down to around 200 hz on a 22-24" wide baffle (like a 12NDA520), crossed on the bottom end to something like that monster 20" and on the top to a ribbon or an AMT would be a modern equivalent to that monstrosity I was playing with. I realize a 20" woofer isn't going to be eveyone's solution, but for those with the room, I think it might be great.

I pursued that link and it took me to the Canadian manufacturer:

http://www.maxspeakers.com/products/...nal/index.html

I was put through to one of the designers (Frank) who sounded very well informed and also accommodating. He told me that particular woofer, the PR 20-120, was no longer being made, as the company that made the cone had gone out of business. They have another similar - the PR 20-125 - which is actually quite different in Maxspeakers' attempt to give the market what it apparently wants. Heavier cone, longer VC, much higher power handling, lower fs.

Frank did say, though, that they can build virtually anything describable for orders of 100 or more, including hemp cones, Alnico.

As far as high sensitivity 12" he said most were for guitars and need an 8dB peak at about 6kHz to please the typical guitarist. In fact they made a very flat measuring 12 intended for guitars but it was so unpopular they had to sell it in the South American market at surplus prices!

Anyway, a 12" Alnico, hemp coned, flat measuring speaker is no problem.

Listening to it before 100 were made is the problem!

P.S. Frank said that the 20" speaker is not significantly larger than an 18 in most practical respects. On the other hand the 21" model is.....!

[Variac]

OK, I know we are all trying not to post every driver out there, but I finally lost control wot a surprise...
This is the the Eminence 15" Neodymium Deltalite:
http://www.eminence.com/pdf/deltaliteII2515.pdf

The 15 has a very smooth curve and goes up past 2k, then drops like a cliff. Could it be a good helper driver to fill in below the wide range 12" It only costs $120, the neo magnets seem to be considered better sounding than ferrite, and the basket is very minimal-certainly good characteristics on an open baffle where you don't want obstructions behind the cone. Heck , it will save you another $20 in shipping too 'cause it's so light.

[johninCR]

Variac,

Thanks for pointing out that Eminence. That's an interesting reasonably priced option.

[fiacono]

the Eminence 15" Neodymium Deltalite:

Lynn's proposed option two we need 16 ohms...

Frank

[Pano]

A buddy of mine has a pair of the Neolite 15s. Think he liked them for OB. Will ask when he gets back from LSAF in Dallas.

[johninCR]

Originally posted by panomaniac
A buddy of mine has a pair of the Neolite 15s. Think he liked them for OB. Will ask when he gets back from LSAF in Dallas.

Just about any driver sounds better in OB. My question would be whether or not they are as smooth as the Eminence graph indicates. Maybe those EnABL and/or Mamboni cone mods could make the Neolite12 useable out to 3 or 4khz.

[Lynn Olson]

On the coax front don't forget the BMS 12C262. For the woofer crossover, use a 6 dB/octave filter starting at 1.8 kHz and a notch filter tuned to 2.2 kHz with about -6 dB attenuation.

Set the tweeter highpass to 2.2 to 2.5 kHz, and as mentioned before, adjust the tweeter slope until the crossover yields a -20 dB or better null when temporarily reversed-phased.

Use this coax with either Project One or Two OB bass/midbass configurations.

All done. Listen and enjoy.

[Lynn Olson]

On May 1st, I went into the doctor for my X-ray, to see the progress I've been making. These days, there's no film, and pictures appear on a flat-screen computer monitor in a consulting room. The doctor who did the original surgery on January 8th showed up, and fortunately, the Kaiser clinic wasn't too crowded, so we had more time to talk.

At first, I was disappointed. There was still an obvious break in the tibia (the larger leg bone), but the fibula appears completely healed. But just as I was starting to feel discouraged, the doctor switched the display to the previous X-ray taken on March 20th, and this time, the differences were quite apparent. The fractured area had decreased in length by about half, and the remaining open area was filled with a dim, cloudy blur.

This dim, cloudy blur were bone cells in the first stage of forming new bone: apparently, at the area of a bone break, the cells revert to their initial soft, gelatinous form, and move around and arrange themselves where the new bone is going to be laid down. Then, once they're in place, they lay down a 3D matrix of calcium, start to become stronger and more rigid, and finally, bone marrow production starts up again. This is what was happening in the tibia; it barely shows up in a flat X-ray, but it is quite significant, showing the first signs the fracture is repairing itself.

Based on the surgeon's assessment of my progress, my left leg was now at a stage where small loads would encourage further bone repairs, so I was authorized to put 30 lbs of weight on the leg, see what it feels like, and practice with a ball and using the walker in a left-right-left-right pattern of walking again. After a week, the permissable weight goes up to 60 pounds, the week after 90 pounds, and the week after that, 120 pounds. Morever, this isn't instantaneous peak pressure; this is steady-state weight, so after week four, I can walk using both legs equally - although with the assistance of a cane, crutch, and wearing the removable boot as I move around.

I will go in for a followup X-ray in 6 weeks, in mid-June. The doctor's estimation is the complete process will take six months, recalling BudP's six-month experience he went through as a teenager. So it looks like I'll be walking again by my birthday on August 10th, wonderful news!

I brought the printouts about the electronic gizmos, and like I suspected, the doc knew about them already. He said my recovery was just about in the middle of the curve, not slow, not fast, right in the middle. If it was slow, there would have been no improvement at all on the X-ray, and he would have prescribed the gizmos to get things started. If it was fast, the break would have been completely healed by now.

So I fall in the middle, which I guess is OK for a 57-year-old guy. I give credit to the "The Great Mender" Chinese medicine, calcium pills, the homeopathic pills, regular elevation of the leg and self-massage of the calf muscles, and a lot of visualization. This is my usual approach to a crisis: throw everything at it and see what works. It looks like flailing around, but when you want results, it's probably the best approach.

I want to thank you all of you for raising my spirits when I needed it. This on-going "Beyond the Ariel" project has been stimulating, got me back into hifi in a serious but fun way, and opened up a world of future possibilities. I have great expectations of how this is going to turn out.

In the next day or so, I'll be making some sketches of Versions One, Two, and Three. I still lean towards Two, though - it's kind of a halfway house between the giant, full-on Oris and Azurahorns with their 500 Hz crossovers, and the little bitty horn tweeter of the Bastini Apollo, which I think comes in around 5 kHz or higher.

[Russell Dawkins]

Lynn,
glad to hear your recovery is on track, congratulations!

I wonder if you ever got to hear or see the Emerald Physics DSP controlled dipole.
I was just looking through some old correspondence and came up with these details as to the components used and the crossover frequencies. Thought you might be interested:

(1) BMS 4552 1" compression driver (1250Hz-20kHz)
(1) DDS ENG1 90 degree waveguide mated to BMS
(2) Ciare 8-64 8" midranges in parallel (150Hz-1250Hz)
(3) Eminence Alpha 15A woofers in parallel (<150Hz)
(1) dbx 260 DSP controller (for both channels)

Bass panel is 60" H x 24"W
Mid/treble panel is 60"H x 15"W
Both panel are connected together by 8 solid aluminum rods 18" long and 2" diameter.

If you are not familiar with this speaker, here's a picture (note the current design has 3 not 4 15" bass drivers, and the bass drivers are all in one panel which is attached to the mid/hi panel, logically, so one piece per side, not two):
http://tinyurl.com/32pgwe

Quite a few people thought these were the best or nearly the best sound at the last RMAF.