I worked at an audio store in Anaheim, CA in 1975-6 when the original Advent, JBL L100 and Bose 901 were dominating the market. I heard them (and Dahlquist, Ohm, and ESS) all day long.
I never heard the Dynaco speakers but I had a pair of hand-built floorstanders with dual Danish-built Peerless textile dome tweeters for 12 years.
L100s are physically well built (except for the ubiquitous rotting foam surrounds almost everybody had back then), but the horizontal bookshelf design, adapted from the vertically oriented 4311 studio monitor, was optimized for controlled, almost nearfield listening and had no consideration for (or maybe awareness of) in-room power response. By today's standards, the L100's crossover points are ridiculous--1500 Hz between a 12" woofer and 5" midrange, and 6000Hz between 5" midrange and the 1" tweeter. A 12" woofer starts beaming at 1125 Hz and a 5" midrange starts beaming at 2700 Hz. This means there are significant off-axis suckouts at 1100-1500 Hz and more than a full octave beaming between 2700 and 6000 Hz. If you move off-axis these suckouts give you that "cupped hands" sound. The advantage is that it translates into high power handling capacity.
The Advent, OTOH was designed specifically for linear in-room power response, and Kloss & co. paid special attention to driver size vs. crossover point. The Advent woofer, while mounted in a 12" frame to maximize cone excursion, had a 6.5" cone crossing over to the tweeter at a very low (for a tweeter) 1KHz. A 6.5" diaphragm doesn't completely beam until 2250 Hz. Therefore, the single 1KHz crossover point was not beaming in the slightest. That very low crossover almost certainly accounts for the frequently blown tweeters that came back to us from customers. Advents sounded good on a wide variety of music. Good on rock if you had the amp power, and great on classical, jazz, and pretty much everything else.
The Advent also had *real* bass--audible down into the mid 30Hz region. The L100 started rolling off around 100 Hz and was pretty much MIA by 50 Hz. It seemed to have strong bass because it was a 12" diaphram making big waves at the frequencies it *could* reproduce.
The L100 had a punchier, immediately engaging sound. It was way more sensitive. It could kick ass with a 40 wpc receiver and do pretty good on 20 wpc in a dorm room. The Advent really needed 100-150 to come alive, but we were just starting to learn about that back then, thanks to Bob Carver.
However, let's consider something: In the mid-'70s the L100s were $560/pair ($2500 in today's money). The Advents were about $200/pair. You could have bought a TRIPLE stack of Advents for $40 more than a single pair of L100s. In that showdown, and given that double Advents were already legendary by then, triple Advents would easily have beat the JBLs, with triple woofers making audible bass down to 32 Hz and three tweeters sharing the upper mid/treble load. The also had a 3-way switch on the back to boost the tweeters a bit.
I never heard the Dynaco speakers but I had a pair of hand-built floorstanders with dual Danish-built Peerless textile dome tweeters for 12 years.
L100s are physically well built (except for the ubiquitous rotting foam surrounds almost everybody had back then), but the horizontal bookshelf design, adapted from the vertically oriented 4311 studio monitor, was optimized for controlled, almost nearfield listening and had no consideration for (or maybe awareness of) in-room power response. By today's standards, the L100's crossover points are ridiculous--1500 Hz between a 12" woofer and 5" midrange, and 6000Hz between 5" midrange and the 1" tweeter. A 12" woofer starts beaming at 1125 Hz and a 5" midrange starts beaming at 2700 Hz. This means there are significant off-axis suckouts at 1100-1500 Hz and more than a full octave beaming between 2700 and 6000 Hz. If you move off-axis these suckouts give you that "cupped hands" sound. The advantage is that it translates into high power handling capacity.
The Advent, OTOH was designed specifically for linear in-room power response, and Kloss & co. paid special attention to driver size vs. crossover point. The Advent woofer, while mounted in a 12" frame to maximize cone excursion, had a 6.5" cone crossing over to the tweeter at a very low (for a tweeter) 1KHz. A 6.5" diaphragm doesn't completely beam until 2250 Hz. Therefore, the single 1KHz crossover point was not beaming in the slightest. That very low crossover almost certainly accounts for the frequently blown tweeters that came back to us from customers. Advents sounded good on a wide variety of music. Good on rock if you had the amp power, and great on classical, jazz, and pretty much everything else.
The Advent also had *real* bass--audible down into the mid 30Hz region. The L100 started rolling off around 100 Hz and was pretty much MIA by 50 Hz. It seemed to have strong bass because it was a 12" diaphram making big waves at the frequencies it *could* reproduce.
The L100 had a punchier, immediately engaging sound. It was way more sensitive. It could kick ass with a 40 wpc receiver and do pretty good on 20 wpc in a dorm room. The Advent really needed 100-150 to come alive, but we were just starting to learn about that back then, thanks to Bob Carver.
However, let's consider something: In the mid-'70s the L100s were $560/pair ($2500 in today's money). The Advents were about $200/pair. You could have bought a TRIPLE stack of Advents for $40 more than a single pair of L100s. In that showdown, and given that double Advents were already legendary by then, triple Advents would easily have beat the JBLs, with triple woofers making audible bass down to 32 Hz and three tweeters sharing the upper mid/treble load. The also had a 3-way switch on the back to boost the tweeters a bit.