The Electronic Subwoofer

[bigyank 0]

Anyone else have one of these? I picked one up last week on a whim to use with my Allison One's. The change is tonal quality is very subtle for the most part.

I never heard of one previously and was wondering when they came out, etc.

Yank

[JKent 0]

Probably more dramatic with a smaller speaker, such as the Four, Five or Six. Here's a copy of the brochure pages, dated 1979.

Kent

[bigyank 0]

Thanks I have a copy of these but was unsure of when they were from. Anyone have a schematic?

[JKent 0]

Just got one (ESW, not a schematic). Had to open it up to De-Ox-It the toggle switch (I thought the unit didn't work but it was just the switch). I'll post a photo. A lot of ICs and stuff in there I wouldn't touch but there are 2 1,000uF 40V electrolytics and I happen to have a couple of nice Nichicon audio grade 1000/50 in my parts box so I may do a little surgery.

Has anyone else been inside? Tom maybe? I know Tom mentioned using this with AR-303s speakers here

I'm trying it out with my AR-91s.

Found an interesting quote in a Stereophile review of a book by Howard Ferstler; "In Howard's mind, "the Electronic Subwoofer failed in the marketplace, in spite of its abilities, for one basic reason: it was actually too good."
 

-Kent

[DavidDru 0]

do tell once you get a feel for it.

[JKent 0]

OK. Cracked it open to install the 1000uF caps and found some other aluminum electrolytics so I replaced those too. There are also some caps that look like styrene and I didn't touch those.

Nice pcb. All the components are marked with the part # and polarity. Here's what I replaced. I used caps I had on hand. The originals were axial, new ones are radial. Had to use heat shrink tubing on the lead because they cross some pcb traces. Yellow arrows on the photo show the new caps.:

• C1 and C2. 1,000uF/40V replaced with 1,000uF/50V Nichicon Audio
• C5, C8, C16, C19, C31, C37. 10uF/40V. Replaced with 10uF/63V Nichicon.

Squirted the EQ/Tape switch some more. It was pretty spotty.

So the result? VERY subtle with AR-91s. A tad more oomph at the bottom. I suspect it would be more impressive with a smaller speaker, like the Allison: Four or any 8" woofer AS speaker such as the AR-4.

Turnover frequency points are 35.5, 41 and 48Hz. I have it set at 35.5Hz.  According to the AR literature the 91's system frequency response is -3dB at 35Hz so I'm guessing the 35.5Hz turnover is right for these speakers. 35.5Hz is the recommended setting for Allison: One and Allison: Three speakers--those have 10" woofers.

 

[mpfrank 0]

I actually have one of these that I bought used on Ebay. I have used it with Allison 115 speakers - 8"woofer - and I couldn't tell any difference. Could be the speakers, could be the room, could be the electronic subwoofer itself, could be the music, could be my ears. Anyway, I'd be happy to sell it if anyone's interested.

[newandold 0]

The Allison Electronic Subwoofer was a great idea back when these speakers were relatively new.

Today, with the average age of Allisons being at least 40 years young, the LAST thing I would be interested in is using a device that is going to have those old woofers working harder than ever.

The opposite is preferred, IMHO....get a competent powered  subwoofer and let that provide the lower frequencies while giving the old Allisons a break.

Save on both amplifier demand and excessive excursion of 40 year plus woofers.

Just sayin

Bill