Mark Hardy

...but it still seems to my untechnical mind that better results would be achieved with an active woofer. Indeed it does, comparing apples to apples. http://www.diysubwoofers.org/prd/ And of course, all things being equal, the rate of LF rolloff of an acoustic suspension speaker (6 dB/octave, IIRC) in a sealed box is much shallower than either "ported" design shown in the graph above. I think Polk, for example, went with a PR in their early speakers 1) To enable use of a small woofer and a relatively small box and still get decent LF performance. The 6" midbass was a good sounding, good performing midrange driver; a 12" woofer likely wouldn't be. 2) To save the expense of an onboard "subwoofer" and crossover. A separate woofer in a small sealed box could've actually provided better LF performance, but at considerably enhanced cost. 3) It was fashionable at the time 4) It does keep small mammals out of the speaker box. I think reason 4) is the best one, looking back over 30-plus years! EDIT: More on PRs (good ol' Google): http://www.subwoofer-builder.com/passive.htm The advantages of a passive radiator design are: No port noise Low tuning can be achieved in a small box. This normally requires long ports with troublesome "pipe mode" resonance and compression Disadvantages: Cost Faster rolloff may require a high-pass filter that an equivalent ported system might just scrape by without.

A passive radiator is a special case of a vent (or port). Its major merit is that it cannot "chuff". They are (to this day, AFAIK) usually tuned empirically, by adding mass to the PR diaphragm. I have owned, and enjoyed, Polk Monitor 7As for almost 30 years. Polk made good use of PRs in their early designs, starting with their first consumer loudspeaker, the Model 9.\ EDIT: Here's a pretty good overview of the PR from good ol' Huw Powell of Human Speakers (keeper of the EPI/Epicure/Genesis flame): http://www.humanspeakers.com/whatis/PR.htm 'n here's a Polk 7A, with a 10" PR and 6" "midbass": 'n HERE's an original Polk Model 10 (10" non-coated PR and two 6" midbass drivers):

"Is that Fisher receiver a 500B? Can't quite tell if that's the tuning eye tube indicator. If so, it's not in the 500C, which is so popular. One of those "model to model improvements" that lost some cool factor, IMO. Very cool." It's a 500C. I have a 500B now that I recently acquired, cheap. It may or may not be a restoration candidate. I like the tuning eyes better, too. By the bye... with the exception of the contour circuit in the little FE103 design, none of th FRs I posted have any contour, Zobel, or BSC (baffle step correction) networks in them. Bob Brines recommends one for the 40-1354 TQWT, but I am perfectly satisfied with them without BSC. GRATUITOUS EDIT: This is the "vertical tasting" of basket case Fishers I picked up this summer. They were inexpensive, and I couldn't resist! The other 500C I have (photo posted earlier) is a nice one, restored by Craig (amp) and Mike Williams (tuner).

Inexplicably, I have a mismatched "pair" of the once-famous, EQ'd R/S 40-1197 minispeakers published in some 1960s electronics magazine :-) They were (separate) dump finds; one sans back/network. (the kitteh is not ingesting the fibreglass, just sniffing) Lots of fun to be had with FRs. The TQWTs now sport drivers that have modified with Dave Dlugos' (www.planetsofta.com) phase plugs. These sound bitchen...

All the time! Here are some of the local favorites: Bob Brines-designed folded mass loaded TQWTs with R/S 40-1354 FR drivers (sometimes augmented with the R/S planar tweeters seen atop them). You may recognize the speaker behind it, too. 1ft^3 Bass reflex (rear ported) cabinets loaded with Fostex FE-207E FRs (designed and built by Dave J.) These little guys are loaded with the once-famous PartsExpress 269-469 "69 cent wonder"; designed and built by my son as part of a HS Science Fair project: These sound very good. You may note a Quad ESL-57 hiding behind the PE speaker. We also like to play with 8" FRs on open baffles sometimes. This photo shows my somewhat homely OBs with the not-bad but also unremarkable 8" twincone Goldwood driver from PartsExpress. Oh, this homely, Pioneer-built 12" Karlson kabinet has a nice EV SP-12B twincone FR in it that sounds pretty OK: If you're interested in FR speakers, visit www.fullrangedriver.com

FWIW: Never been a big fan of Duals. Unnecessarily complex, IMNSHO. If you want/need an automatic tt/changer, then they're pretty good, but for single play you could do better for the $. Again, my NSHO. I have a 1019, BTW. Had a dump find 1219 and another 1019 and gave them away. The 1019 I kept was given to us by a good friend, so I keep it for sentimental value. BTW, I don't think the 1219 was direct drive... EDIT: Nope, the 1219 is also idler (rim) drive: http://www.vinylengine.com/library_model.php?make=Dual&selected_model=1219 Oh, one cool thing about the 1019 (at least). The arm is dynamically balanced, so it can play at absurd angles (or even upside down). Take a look at page 8 of the 1019 manual at: http://www.vinylengine.com/library_model.php?make=Dual&selected_model=1019 If you want idler drive, get a Thorens 124 or a Garrard 301 or 401 :-)

Mine, too.

Speaking of dust cap surgery... This isn't exactly on-topic, because this is for the special case of de-dust-capping to install a phase plug, but the step by step instructions with photos at Dave Dlugos' site might be of some help and/or of interest to the original poster. http://www.planet10-hifi.com/pp-pictures.html Also info at Steve Deckert's site: http://www.decware.com/newsite/mainmenu.htm

You betcha: http://www.tapeproject.com/ Sadly my little decks aren't compatible with the good Doctor's offerings...

Use an X-acto knife with a very sharp (brand new) blade and just remove the old one. Besides mass, some provide some ventilation as part of the cooling scheme for the voicecoil. I wouldn't double 'em up.

See if there's a copy of the original AOXOMOXOA mix (not the 1971 remix). The remix is clearly labeled such on the jacket (covers are the same); green "W7" label. The original mix is very cool, and (in its own way) sounds very good.

"anyone collect them?" Heck, no :-) In all seriousness, the vintage Grundigs, Telefunkens, Normendes, Tandbergs, bang & olufsens, etc., etc. included some terrific radios. Kloss' KLH Model 8 is a classic, but the solid state KLH 21 was also pretty nice, as were his later Advent 400 radio and, truth be told, his last -- the Tivoli Model One and its cousins.

Sadly, Harvey died young (well, at least, unexpectedly and seemingly before his time)... he was quite influential, especially in the realm of (re)popularizing fleapower, single-ended triode amplification and high-efficiency speakers. More like Hunter S. Thompson, though, don't you think?

The 8B is a mofo of an amp... as I said, it might be a starter amp for a hedge fund manager. Craig probably doesn't even know it, but he did the amp rehab on my 500C (and Mike Williams the RF) before it was mine :-) (you can see a Cornie hiding under it and behind a folded TQWT in the photo)

Cornwalls are exceptionally sensitive and will work very well with a good single-ended 2A3 amplifier (e.g., Doc Bottlehead's Paramour II) at a blistering 3.5 watts. IME, they sound fantastic with a Marantz 8B (35 wpc push-pull EL34) but that's only a starter amp for someone who does hedge funds or such for a living. A vintage Fisher pp 7868 or 7591 receiver (400, 500C, etc.) is a very, very nice match. These are about 25 wpc and smooth out the Cornies rough edges quite nicely. I long used mine with a pp EL84 amp; in my case, an EICO HF-81 (ca. 12 wpc). Very, very nice, although NOT up to the 8B. These aren't inexpensive anymore, though. A modest Magnavox pp EL84 or pp 6V6 stereo power amp from a late-'50's/early-60's hifi console would NOT be a bad, nor an expensive, choice. These amps are plentiful and cheap (mine was a dump find). They have simple if bizarre circuit topologies and sound far, far better than they have a right to with relatively minor restoration. You'll note I am heavily biased towards vintage amps. I can explain why if anyone's interested (but y'all probably know the reasons already).