[AR3's with McIntosh MC2300 and a Allision ESW...wow]

On 12/19/2021 at 11:57 PM, teknofossil said:

I was amused at how seemingly complex the ESW is for what is basically and LF EQ and high pass filter. If one can't be found the late S Linkwitz offered a circuit with use info and a spread sheet to construct your own. Of course measurements of the AR or Allison design would be required to accurately compensate for the system characteristics. Below are photos of one I repaired about 8 years ago. High quality assembly (unless you don't agree with the chosen op amps.)

oh, it was very high-quality design, so much CMOS, and as engineer Mark Davis said when looking at the schematic from 45y ago, 'a lot more to it than I recall'

Some of that was to satisfy Allison's typical consumer OCD, specking a product to the half-hertz, come on 

[AR3's with McIntosh MC2300 and a Allision ESW...wow]

On 12/21/2021 at 4:28 PM, samberger0357 said:

Never heard of the Boom Box, but I'm interested in learning more.

David Moran, who I think is a member here but is a longtime member of the Allison Google group and who I acquired the ESW from, worked at DBX(was also a longtime music and audio gear writer for the Boston Phoenix and member of the Boston Audio Society) for a time. Perhaps I can get him to comment on this.

This dbx product, the latest (last) of which had separate filter bands, level-tunable, sampled LF and generated (euphonious) distortion an octave below. I use my 120X-DS rarely, but have a friend who uses an earlier rev all the time w music and movies alike. I guess I should try it on movies. 

Sorry to be so tardy coming back to this group! 

I am at drmoran@aol.com if anyone needs further dbx or other geezing, or any of my manuals, and so on. 

[AR3's with McIntosh MC2300 and a Allision ESW...wow]

On 12/21/2021 at 7:04 PM, Aadams said:

Roy A. was a sly one.  He knew that the ESW worked better on Allisons than on most other brands including AR.

Any Acoustic Suspension Speaker that could withstand the stress such as a Large Advent or AR3, 3a, also had a crossover so high into the midrange that phase or “doppler” distortion could become a problem.  The Allison One, Two and Three had a low crossover of 350hz, low enough that such distortion could not be an issue. 

An ESW combined with the 1000hz crossover of a Large Advent or AR3 would be a doppler distortion generator.  

AR didn’t avoid phase distortion from amplified low bass frequencies until the AR9.

 

Nah, none of this is true. Doppler distortion is not a thing audibly. As Allison showed in papers w Villchur, who wrote the definitive debunking ones. 

ESW works superbly on Advents and ARs of any vintage, I know firsthand. Just superbly. And lesser Allisons (LC110, e.g.). 

[I have Allison 130's here... Rare? Any info appreciated...]

I wonder what the backstory on this unique (or close to it) / prototype? unit is, because the LC130 as widely produced is a 2-way design in walnut vinyl 

http://www.classicspeakerpages.net/library/allison/other/allison_speakers_in_1983_an/allison_speakers_in_1983.html

Not really anything to do w the AL130 except the same mid and tweet, which is the case w every Allison or RDL ever made 

[RDL Acoustics F-1]

Just some notes and errata, sorry to be so tardy in posting.  

The AA and RDL lines actually sold a fair amount of product over their lifespans, especially after CU (and many other mags) raved about the Six, CD6, and S1. The reason they do not show up used so often is that owners keep and like them. They do sound better --- especially when placed such that the woofers face each other --- than other 2-ways, by a margin. 

So did, for a while, AA with the original Ones (and to a lesser extent the Two and Threes). The Fours were always a seriously big seller. Someone should revive the Four even w conventional drivers. What sound. 

The shiny sticky layer was added to preserve driver and surround longevity, and dust and crud and dog hair settled thereupon make zero sonic difference. I would never spend time scrubbing them clean, if only for fear of damaging or offcentering the voicecoil (or harming surround or spyder). 

The drivers in the RDL and the AA and LC lines are all identical; actually, there may be slight variances in the 8" woofers, adaptive to cabinet volume, details about which are available in the Allison io (google) group and possibly in the new Facebook group (I am trying to get them to overlap, of course). 

The newer 'nipple' tweeters (RDL) do not have stranded-lead corrosion problems, I believe, as in some earlier AA models. Even better, Kentucky used the original tweeter design, not OEM, for all Allison-branded designs, and in fact their manufacturer poor Eminence laboriously and nontrivially improved on it, a simply remarkable achievement, given what a complete bear it is to manufacture. (I cannot get OEMs to even look at it.) 

The RDL lines is identical to the AA CD5, 6, and 7, and those were improved over their originals only (or at least chiefly) from having a steeper highpass (12dB) to the tweeter, to protect it in the new digital era back when. The difference b/w the B1 and the FS1 (hope I have it right) is solely the VLF reach, similar to the diff b/w the Six and the Five/Seven or b/w the LC120 and LC110, the latter of which must be the best-performing wideband cheapy in history. 

Anyway, if you have not done so already, I urge joining the Fb and io Allison groups. More info than you'll ever need, probably. I just uploaded an ESW schematic that came into my possession, the only one uncovered ever. Its designer Mark Davis (dbx Soundfield, Dolby AC3, and much more) could not believe how complex and rich it was .... 

[Allison IC-20'S (in original boxes for 20 years!)]

you guys do know about the very active Allison speaker group online, yes? 

allison-speakers@groups.io 

all questions answered plus tips 'n' tricks 

 

[The Electronic Subwoofer]

This is a superb, subtle unit, usable with any sealed woofer and even with some vented if their design goes low (LF) enough; one's not sensing it reflects only on program and system and room lossiness, nothing more. 

(Its steep >bandpass filtration alone should be something all preamps or power amps should already have.) 

It was engineered for Roy Allison by his friend Mark Davis, MIT PhD EE/psychoacoustics, of dbx and Dolby fame; at the former he was the designer of the Soundfield Imaging shaped phased-array loudspeaker line (not unlike Allison speakers in getting treble into the reverberant field) and the compansion circuit which led to US stereo TV, and at the latter for multichannel codecs / AC3 development and much more. AES silver medalist. A colleague of mine for many years (like RA) and a good friend before and after. A wizard at loudspeaker radiation pattern implementation, prediction, and simulation, among many other things. Author of the two most sensible lay papers ('78 and '82) on audio and hearing. A Floyd Toole type, in sum. 

I will answer the tape loop hookup query privately. Pre out / amp in works fine, but a tape loop is often preferable as to noisefloor and reduced potential for overdriving (distortion). 

[allison eight]

Prime prime opp for someone in Florida, Tallahassee area; excellent speaker, wideband, smooth, airy, needs open shelf or mantel --- Allison Eight, 3-way. Don't know price, but not expensive. Walnut. Mint.