7. Old tweeters are the weak link in these old speakers. They can be fried very easily with modern powerful amps and CD or especially SACD sources. Ferro-fluid cooled tweeters weren't invented until later. Also, the suspensions of even in-box NOS tweeters have, after 40 years, stiffened up enough to sound quite "soft" if newly pressed into use now. Many restorers, including me, have taken to using modern ferro-fluid drivers chosen for sonic similarity to the originals when used with a modified crossover. Vintage AR recently started selling some very nice modern tweeters for use in AR speakers and sells them with the crossover mod attached as part of the tweeter assembly itself.
8. Many restorers find that these old speakers can in fact image better than they remember. Part of this is that modern speaker set up techniques, such as mounting the speakers away from room boundaries, help. But that messes with the tonal balance, which is the big appeal of such designs. Most vintage speakers were designed to sound best used against a wall.
Imaging problems intrinsic to the speaker design are primarily caused by the raised lip around the front baffle of the speaker which was an almost-universal design element of vintage speakers. The sonically best solution would be to saw it off and re-stain the cabinet edge. But then the speakers would not look like they originally did. You could also ameliorate the problem by using thick felt padding over the entire front baffle surface, leaving holes in the felt only around the drivers. Use layers of felt to build up the front baffle until it is even with the decorative edge. Some even try molding clay-like substances (like Mortite) to the baffle to gradually ramp up from the flat baffle surface to the decorative edge.
9. Some professional restorers like Orange County Speaker and Van L Speakerworks ( http://www.montagestudio.com/van/repairs.htm ) in Chicago offer fairly reasonable rates on "re-coning" drivers, making the cost and labor of the re-coning kits less of a bargain, especially considering the problems involved in doing the work yourself in terms of keeping the voice coils aligned, etc. From Kewanee, you could hand deliver speakers to Van L and avoid shipping risk. Jon Vann is a very nice guy and knows good sound. I purchased some Totem Dreamcatcher speakers from him a number of years back for a home theater system and have never regretted it.
9. Moving on to your vintage equipment reviews, I owned the Audionics BT-2 and CC-2 amps (a pair of these amps, actually) back when I had Snell Type A Improved speakers. Yes, these electronics sounded pretty good compared to most other stuff at the time. But the BT-2 had a subtle "crunch" distortion when hit with mid and treble transients. I heard this when I owned it, but did not realize its seriousness until I replaced it with the much cheaper NAD 1020 preamp (the preamp section of the famed 3020 integrated), which was superior in every way.
The CC-2, while very smooth and clear, lacked bass power and punch with the Snells. I tried bi-wiring and bi-amping, horizontal and vertical with Snell's electronic crossover. I found the Amber 70 amp to be superior in the bass, with comparable talents further up the range and eventually replaced the CC-2 pair with a single Amber. Neither amp was really right for the Snell speakers, however, as I only found out much later when I heard a Luxman 200-watter on those speakers--suddenly the bass was extremely powerful and more extended with at least equal performance further up.
10. Earlier, I'd owned four Large Advent speakers, two in college and later added two more in law school. I agree with your assessment of these entirely, especially the lack of sonic transparency of the grills. Once I had four, I used them either in a Dynaquad-type surround system (but with a separate integrated amp for the rear pair so as to gain full control over rear level and balance) or "stacked" with the top pair upside down atop the bottom speakers, with the two sets wired in parallel. I always knew there were better speakers around than the Advents, but liked the set of compromises the Advents offered at their price. The bass was not the equal of the AR-3a or KLH Model 12, the frequency balance not so smooth, and the highs not so extended or filigreed. But at half the price of those others the Advents could play louder without destroying the tweeters, the drivers were more integrated, they imaged better, and just generally had a balance which better suited the rock and jazz music I then favored.
By the way, the Advents had great bass balance and imaged/staged like gangbusters when placed well off the floor when my roommate and I put the front pair vertically atop our school desks in the corners of our 12' x 18' dorm room. So placed, the tweeters were at ear level when comfortably seated in our standard desk chairs. The surround pair was placed horizontally atop the bookcases in the upper rear corners of the room and angled out and down a bit on wooden supports we built so they could face the front part of the room. My Pioneer amp drove the front pair. My AR integrated amp drove the rear pair with the amp's selector switch in the center "Null" position which subtracted left from right (like Dynaquad) and with the speakers wired out of phase with each other.
11. Ah, "those were the days," as they say. Recapturing some of the joy of a more innocent time IS very enjoyable. But in my saner moments I realize that we really have come a considerable distance in speaker performance, at least, since that time. Modern speakers can run rings around the golden oldies in many important ways, including lack of distortion and consequent clarity, bass power, micro- and macro-dynamics, imaging, and soundstaging.
12. But I don't really think we have made much real progress in terms of tonal reality, and that's what makes these old speakers so much fun to listen to. The old speakers have the "tonal juice" some of us crave. Realistic bass heft without boom, lower midrange warmth, midrange smoothness, and relaxed, sweet highs. When played back through the old AR speakers, modern CD recordings produce a tonal balance closer to what one hears live from the audience at an unamplified classical music concert in a decent concert hall than most modern speakers. The designers of these old speakers were trying for that kind of realism and made some very astute design compromises given the technology available at the time to get very close indeed.
Much of high-end audio took a detour beginning in the late 1970s into the pursuit of spatial artifact reproduction, a detour from which it has not yet recovered. Accurate tonal balance was sacrificed on the altar of giving our eyes something to do by creating detailed spatial artifacts. Even with only two reproduction channels we can now hear more about the apparent spatial relationships of the performance than one could ever hear at a live concert with your eyes closed.
Such spatial effects are fascinating for the listening room, yes. But realistic they are not. Audio reproduction has become a thing unto itself. No one seems to care that you can't tell an oboe from a clarinet or even a bassoon on many modern speakers, as long as you can "see" the singer's lips part centered tightly in space in front of the speaker plane and hear the spittle surface tension break before the first word comes out of her mouth. Never mind that such effects would never be heard live and unamplified, and would even be uncommon in a live amplified concert with the singer holding the mike to her lips.
********************
If, besides hanging around this forum, you sign up for REG's (Robert E. Greene of TAS) audio forum on Yahoo, you can see various pictures and measurements of my speakers and systems in my photo album there. See: http://groups.yahoo.com/group/regsaudioforum/ for the home page of that forum and, if you sign up, you can see my photos at:
http://groups.yahoo.com/group/regsaudioforum/photos/album/404627898/pic/list
8. Many restorers find that these old speakers can in fact image better than they remember. Part of this is that modern speaker set up techniques, such as mounting the speakers away from room boundaries, help. But that messes with the tonal balance, which is the big appeal of such designs. Most vintage speakers were designed to sound best used against a wall.
Imaging problems intrinsic to the speaker design are primarily caused by the raised lip around the front baffle of the speaker which was an almost-universal design element of vintage speakers. The sonically best solution would be to saw it off and re-stain the cabinet edge. But then the speakers would not look like they originally did. You could also ameliorate the problem by using thick felt padding over the entire front baffle surface, leaving holes in the felt only around the drivers. Use layers of felt to build up the front baffle until it is even with the decorative edge. Some even try molding clay-like substances (like Mortite) to the baffle to gradually ramp up from the flat baffle surface to the decorative edge.
9. Some professional restorers like Orange County Speaker and Van L Speakerworks ( http://www.montagestudio.com/van/repairs.htm ) in Chicago offer fairly reasonable rates on "re-coning" drivers, making the cost and labor of the re-coning kits less of a bargain, especially considering the problems involved in doing the work yourself in terms of keeping the voice coils aligned, etc. From Kewanee, you could hand deliver speakers to Van L and avoid shipping risk. Jon Vann is a very nice guy and knows good sound. I purchased some Totem Dreamcatcher speakers from him a number of years back for a home theater system and have never regretted it.
9. Moving on to your vintage equipment reviews, I owned the Audionics BT-2 and CC-2 amps (a pair of these amps, actually) back when I had Snell Type A Improved speakers. Yes, these electronics sounded pretty good compared to most other stuff at the time. But the BT-2 had a subtle "crunch" distortion when hit with mid and treble transients. I heard this when I owned it, but did not realize its seriousness until I replaced it with the much cheaper NAD 1020 preamp (the preamp section of the famed 3020 integrated), which was superior in every way.
The CC-2, while very smooth and clear, lacked bass power and punch with the Snells. I tried bi-wiring and bi-amping, horizontal and vertical with Snell's electronic crossover. I found the Amber 70 amp to be superior in the bass, with comparable talents further up the range and eventually replaced the CC-2 pair with a single Amber. Neither amp was really right for the Snell speakers, however, as I only found out much later when I heard a Luxman 200-watter on those speakers--suddenly the bass was extremely powerful and more extended with at least equal performance further up.
10. Earlier, I'd owned four Large Advent speakers, two in college and later added two more in law school. I agree with your assessment of these entirely, especially the lack of sonic transparency of the grills. Once I had four, I used them either in a Dynaquad-type surround system (but with a separate integrated amp for the rear pair so as to gain full control over rear level and balance) or "stacked" with the top pair upside down atop the bottom speakers, with the two sets wired in parallel. I always knew there were better speakers around than the Advents, but liked the set of compromises the Advents offered at their price. The bass was not the equal of the AR-3a or KLH Model 12, the frequency balance not so smooth, and the highs not so extended or filigreed. But at half the price of those others the Advents could play louder without destroying the tweeters, the drivers were more integrated, they imaged better, and just generally had a balance which better suited the rock and jazz music I then favored.
By the way, the Advents had great bass balance and imaged/staged like gangbusters when placed well off the floor when my roommate and I put the front pair vertically atop our school desks in the corners of our 12' x 18' dorm room. So placed, the tweeters were at ear level when comfortably seated in our standard desk chairs. The surround pair was placed horizontally atop the bookcases in the upper rear corners of the room and angled out and down a bit on wooden supports we built so they could face the front part of the room. My Pioneer amp drove the front pair. My AR integrated amp drove the rear pair with the amp's selector switch in the center "Null" position which subtracted left from right (like Dynaquad) and with the speakers wired out of phase with each other.
11. Ah, "those were the days," as they say. Recapturing some of the joy of a more innocent time IS very enjoyable. But in my saner moments I realize that we really have come a considerable distance in speaker performance, at least, since that time. Modern speakers can run rings around the golden oldies in many important ways, including lack of distortion and consequent clarity, bass power, micro- and macro-dynamics, imaging, and soundstaging.
12. But I don't really think we have made much real progress in terms of tonal reality, and that's what makes these old speakers so much fun to listen to. The old speakers have the "tonal juice" some of us crave. Realistic bass heft without boom, lower midrange warmth, midrange smoothness, and relaxed, sweet highs. When played back through the old AR speakers, modern CD recordings produce a tonal balance closer to what one hears live from the audience at an unamplified classical music concert in a decent concert hall than most modern speakers. The designers of these old speakers were trying for that kind of realism and made some very astute design compromises given the technology available at the time to get very close indeed.
Much of high-end audio took a detour beginning in the late 1970s into the pursuit of spatial artifact reproduction, a detour from which it has not yet recovered. Accurate tonal balance was sacrificed on the altar of giving our eyes something to do by creating detailed spatial artifacts. Even with only two reproduction channels we can now hear more about the apparent spatial relationships of the performance than one could ever hear at a live concert with your eyes closed.
Such spatial effects are fascinating for the listening room, yes. But realistic they are not. Audio reproduction has become a thing unto itself. No one seems to care that you can't tell an oboe from a clarinet or even a bassoon on many modern speakers, as long as you can "see" the singer's lips part centered tightly in space in front of the speaker plane and hear the spittle surface tension break before the first word comes out of her mouth. Never mind that such effects would never be heard live and unamplified, and would even be uncommon in a live amplified concert with the singer holding the mike to her lips.
********************
If, besides hanging around this forum, you sign up for REG's (Robert E. Greene of TAS) audio forum on Yahoo, you can see various pictures and measurements of my speakers and systems in my photo album there. See: http://groups.yahoo.com/group/regsaudioforum/ for the home page of that forum and, if you sign up, you can see my photos at:
http://groups.yahoo.com/group/regsaudioforum/photos/album/404627898/pic/list
