Powered Advents?

Found a pair of these today, not bad cosmetics, rotted surrounds, apparently functional amps though I haven't listened to them and a price too good not to take a chance. Google provides the usual mixed information and a lack of details as does search here.

Can anyone share any experiences with them or information about specs and controls or maybe even a source of owners and service manuals. Never had a speaker before that requires a service manual. Not sure whether they want just preamp input or how to utilize the adjustable input levels.

All help appreciated.

PM me and I'll send you some information

I've done so.

Thanks

Many thanks Carl, the info is very helpful.

I had been trying to locate the info posted at the fisherdoctor site, but the site no longer exists. I went through the entire Advent archive at the classicspeakerpages forum and stumbled across the high-res schematic .gif that came from there as well as some other bits.

schematic: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2719


FR: ...................

"Advent began producing "The Powered Advent Loudspeaker" back in 1977 or 1978, I think, and it was a powered two-way loudspeaker that cost $450. A comparable, standard, "The Advent Loudspeaker" system would have to be biamped, equalized and powered by two 80-watt amplifiers for each speaker to be equal to this powered version. Few, if any, standard Advents were set up this way, of course, due to the complexity, so this new unit offered a unique setup in a single package. The key was that this loudspeaker system did have the proper equalization and filtering, along with electronic crossover rather than the customary passive crossover unit. The result was a system capable of relatively smooth, flat output through most of the audio range.

This unconventional system had a subsonic filter and a variable equalizer to adjust the deep bass from a point approximately 30 Hz and above, so that the deep bass could be elevated somewhat in contrast with the standard Advent system, which began to roll off below 50 Hz. There were controls on the front of the speaker that enabled flexibility in input and the frequency output from the speakers.

This system was tested by CBS Labs, and from the notes I have, they gave the system high marks. They felt that it had a very transparent sound with lots of dyamic range and excellent imaging. Complaints about this system (which was not particularly a commercial success), were that the speaker had a tendancy towards brightness at times, making some instruments sound somewhat harsh, and some crossover-region transient-response problems (some "ringing" around 3 kHz) which could blur the sound in that region, but probably rarely audible. Harmonic distortion in the octave below 40 Hz was not as low as some comparable speakers; for example, The Powered Advent had distortion figures that were significantly higher than a comparable Acoustic Research AR-10Pi measured at the same SPL output. But then again, not much music resides in the octave below 40 Hz, so this is probably a moot point.

Overall, this was an excellent speaker system that did not represent particularly good "value-per-dollar." I do not know how long Advent continued to market the system, but there were not large numbers sold. "

crossovers: .............

"The woofer section is flat up to the 12db/oct rolloff at about 4500hz. The lower end can be boosted up to 6db at 30hz if desired. You can also throw in a 6db/oct rumble filter below 20hz if desired. The tweeter section rolls off below about 4500 too, first at 6db/oct, then going to 12 db/oct. below about 1500. I've not yet tested the Drivers to see what they are doing acoustically, but clearly the electrical crossover is much higher than the original Advent passive crossovers. If the woofers have a gradually falling high end (not hard to imagine with that heavy cone & a ten inch diameter!), and if the tweeter response actually rises below 5000 down to it's resonance, then the actual "acoustic" crossover could be lower than 4500, maybe even match that of the original design - or the 1500hz published. If this proves the case it could explain why this design had apparently better "highs" than the passive models with the same drivers. The tweeters would have been basically flattened electronically and boosted in amplitude....and the bass improved in depth by the added boost on the low end."

"As far as the frequency response, remember that you are looking at a bi-amped speaker with an electronic crossover. By tweaking the electronics you can get a "flat" response from most any reasonable driver combination. All but a few of the very best powered monitors have EQ curves built into the amps to flatten them out."

This on the tweeters: ..........

"the 'powered Advent' apparently was first produced with the 'real Advent' rolled cone/ dome tweeter - the 2 nd gen. higher output version. (from a mag. test 1978) with crossover @ 1500. Built in amp was 80 watt for bass, and seperate 80 watt for tweet , tested response was +- 4 db from 30 hz -14,000 (excel. even today. or is that way better than today ?) Later the powered Advent apparently got the 1" dome tweet used in the 5012 model.
By '79 the orange dome tweeters were already a dated design. Studio people weren't thrilled with them and they couldn't take the power off the internal amp. Advent bought a soft poly dome tweeter from a European supplier [either Peerless or Phillips, never have been able to pin down which] and used an adapter plate to fit it in the oversized stock cutout. These tweeters sounded better, and with a more modern voice coil design, were able to take the power of the built-in amp. By the next model year...POOF...we start seeing Advent's own version of this poly dome tweeter in all their models."

I have a test report on powered advents from "Stereo" magazine in the late 70's (perhaps the test report alluded to above). I'll see it I can locate it. I think it was prior to the dome tweeter upgrade mentioned.

I got the info. from the Fisherdoctor site originally some years back in anticipation of doing some work on a powered Advent. I simply pieced it all together in the word file I sent you.
Too bad the Fisherdoctor site is down now.

Had a good look at them today and hooked them up to the pre-outs of an old Heathkit 1400a.

They need some work. The tweeters have shredded domes from dented mesh covers though the cones are fine. Except for surrounds, the woofers are in good shape but the amps will need some attention. One seems to work fine, the other is intermittent. This is going to be an interesting project. I have a few others to clean up and move out first, but when they're done, I'll do a full-on restoration of these.

lab, that would be great if you could find the review. Since the fisherdoctor site is gone, it seems a good idea to collect the information on these rare birds here.