My discussions of vintage speakers on the WBF so far are here (the AR-3a discussion part), here and here. Rather than put this comment in the Vintage Forum, I've opted to keep it here.
In recent years I've owned three pairs of AR-3a, the AR 303as, as well as two pairs of AR-5, a pair of AR-2ax, and a pair of AR-4x. I thus think I can comment usefully on the differences between the circa 1970 AR-3a and the circa 1995 AR-303a.
The 3a was designed in the late 1960s, while the 303a was a 1995 design. There was thus considerable time for advance in driver design. The designers were different people as well. The 1995 design is really quite a different animal and does not sound much like the older models except in the bass.
The AR-3a, despite being some 45 years old now, is often available on the used market on eBay or Craigslist. There are usually multiple pairs available at once. It sold well for many years and still has many enthusiastic admirers.
The AR-303a is much, much rarer on the used market. It was only sold for a very few years. A pair only turns up on the used market once every couple of years or so. When they are available, they command higher prices than the 3a.
What are the differences? For one thing the 303a has ferrofluid tweeters, so they can play louder and the treble can be run at full level at high volume without significant distortion problems or chance of burn out. The 3a tweeter is "protected" a bit by the crossover and run at a lower level, meaning that the top octave rolls off a few dB or more compared to the 303a. The 303a has no driver level controls, so you are stuck with the chosen balance. The 3a tweeter and midrange can be adjusted over a wide range, but even at maximum tweeter level, the top is rolled off a bit compared to the 303a. The 303a can be biwired or biamped (I biamped them with my Arcam AVR-600), the 3a cannot. The physical driver arrangement is much different; the AR-303a has its driver laid out one above the other but were made in mirror imaged pairs (the mid/tweet should be placed toward the center of the room, not on the outside nearer the side walls). The AR-3a are not mirror imaged and the midrange and tweeter are more or less horizontally aligned.
The 303a sounds clearer and goes yet deeper in the bass, and has even more bass impact than the 3a. In my living room system the 303a would never, ever need a subwoofer even for high-volume reproduction of the lowest organ pipes. I've never heard a speaker that small produce such powerful, extended bass--truly remarkable.
The 303a is balanced more brightly at the top, but the midrange, like the 3a, is very flat and accurate sounding, as is the bass. It is a more "revealing," more "modern" sounding speaker because of this. It is right at home with both rock and pop music and the bass and midrange are wonders. The imaging and staging are superior to the 3a
And yet . . . . The 3a is balanced more concert-hall naturally. The 3a and AR-5 just sound tonally more like live unamplified classical music sounds in a concert hall. Relaxed, full range, clear enough, and the bass is full and rich yet tight enough to never, ever have the type of midbass excess which the Harbeth M40 and M40.1 can easily have in my audio room, and without nosediving in the bottom octave the way those Harbeths always do in my audio room. There is a reason these AR-3a speakers fooled people in live v. recorded demos. Yes, you can point to flaws compared to modern speakers, but they sound "right" in ways that few modern speakers can match.
I have used the 303a only vertically on tall stands, 24" tall. I have used the 3a that way, as well as horizontally at ear level or above in a bookcase. The 3a works well either way. Both speakers like to be close to the wall behind them. Both sound fine toed in toward your ears or pointing straight ahead.
The main problem with the 303a is that it is a bit aggressive and forward sounding in the presence range (2 kHz to 5 kHz) and the highs are ruler flat out to 20 kHz.. The response measures very flat from low bass to upper treble, flatter than most other speakers I've measured. But as I've found over the years, speakers which measure flat don't sound flat, they sound tipped up toward the highs.
I tried various ways to tame the top end aggression of the 303a. The best method was to attach a single sheet of Kleenex tissue paper (one layer of a two-ply Kleenex-brand facial tissue) to the inside of the grill cloth so as to cover the area where the midrange and tweeter are. This reduced the measured highs by about 2 dB over a quite wide range. I lived with them fairly happily that way for about a year in my living room system.
Still, in the end, I decided the highs were still too aggressive for the most natural replay of classical music. What the AR-3a and AR-5 could do effortlessly, these had trouble mimicking. Adding more tissue layers did not help, but instead started to fuzz up the presentation as if I were adding distortion. Of course, you could always try an equalizer, but I never bothered since I also had the 3a on hand and that speaker is magic in terms of balance with classical music.
If your tastes lean toward a brighter sound than the AR-3a, and especially if you rarely listen to classical or other purely acoustic music, then the strengths of the 303a may well make it the better choice. But for those looking for more natural presentation of orchestral, vocal, choral, and folk music, the AR-3a is definitely a better choice. Thus for the classical music lovers, there is no need to hunt for the rare AR-303a. Just be prepared to pay for or perform a lot of restoration on a 45-year-old pair of AR-3as.
In recent years I've owned three pairs of AR-3a, the AR 303as, as well as two pairs of AR-5, a pair of AR-2ax, and a pair of AR-4x. I thus think I can comment usefully on the differences between the circa 1970 AR-3a and the circa 1995 AR-303a.
The 3a was designed in the late 1960s, while the 303a was a 1995 design. There was thus considerable time for advance in driver design. The designers were different people as well. The 1995 design is really quite a different animal and does not sound much like the older models except in the bass.
The AR-3a, despite being some 45 years old now, is often available on the used market on eBay or Craigslist. There are usually multiple pairs available at once. It sold well for many years and still has many enthusiastic admirers.
The AR-303a is much, much rarer on the used market. It was only sold for a very few years. A pair only turns up on the used market once every couple of years or so. When they are available, they command higher prices than the 3a.
What are the differences? For one thing the 303a has ferrofluid tweeters, so they can play louder and the treble can be run at full level at high volume without significant distortion problems or chance of burn out. The 3a tweeter is "protected" a bit by the crossover and run at a lower level, meaning that the top octave rolls off a few dB or more compared to the 303a. The 303a has no driver level controls, so you are stuck with the chosen balance. The 3a tweeter and midrange can be adjusted over a wide range, but even at maximum tweeter level, the top is rolled off a bit compared to the 303a. The 303a can be biwired or biamped (I biamped them with my Arcam AVR-600), the 3a cannot. The physical driver arrangement is much different; the AR-303a has its driver laid out one above the other but were made in mirror imaged pairs (the mid/tweet should be placed toward the center of the room, not on the outside nearer the side walls). The AR-3a are not mirror imaged and the midrange and tweeter are more or less horizontally aligned.
The 303a sounds clearer and goes yet deeper in the bass, and has even more bass impact than the 3a. In my living room system the 303a would never, ever need a subwoofer even for high-volume reproduction of the lowest organ pipes. I've never heard a speaker that small produce such powerful, extended bass--truly remarkable.
The 303a is balanced more brightly at the top, but the midrange, like the 3a, is very flat and accurate sounding, as is the bass. It is a more "revealing," more "modern" sounding speaker because of this. It is right at home with both rock and pop music and the bass and midrange are wonders. The imaging and staging are superior to the 3a
And yet . . . . The 3a is balanced more concert-hall naturally. The 3a and AR-5 just sound tonally more like live unamplified classical music sounds in a concert hall. Relaxed, full range, clear enough, and the bass is full and rich yet tight enough to never, ever have the type of midbass excess which the Harbeth M40 and M40.1 can easily have in my audio room, and without nosediving in the bottom octave the way those Harbeths always do in my audio room. There is a reason these AR-3a speakers fooled people in live v. recorded demos. Yes, you can point to flaws compared to modern speakers, but they sound "right" in ways that few modern speakers can match.
I have used the 303a only vertically on tall stands, 24" tall. I have used the 3a that way, as well as horizontally at ear level or above in a bookcase. The 3a works well either way. Both speakers like to be close to the wall behind them. Both sound fine toed in toward your ears or pointing straight ahead.
The main problem with the 303a is that it is a bit aggressive and forward sounding in the presence range (2 kHz to 5 kHz) and the highs are ruler flat out to 20 kHz.. The response measures very flat from low bass to upper treble, flatter than most other speakers I've measured. But as I've found over the years, speakers which measure flat don't sound flat, they sound tipped up toward the highs.
I tried various ways to tame the top end aggression of the 303a. The best method was to attach a single sheet of Kleenex tissue paper (one layer of a two-ply Kleenex-brand facial tissue) to the inside of the grill cloth so as to cover the area where the midrange and tweeter are. This reduced the measured highs by about 2 dB over a quite wide range. I lived with them fairly happily that way for about a year in my living room system.
Still, in the end, I decided the highs were still too aggressive for the most natural replay of classical music. What the AR-3a and AR-5 could do effortlessly, these had trouble mimicking. Adding more tissue layers did not help, but instead started to fuzz up the presentation as if I were adding distortion. Of course, you could always try an equalizer, but I never bothered since I also had the 3a on hand and that speaker is magic in terms of balance with classical music.
If your tastes lean toward a brighter sound than the AR-3a, and especially if you rarely listen to classical or other purely acoustic music, then the strengths of the 303a may well make it the better choice. But for those looking for more natural presentation of orchestral, vocal, choral, and folk music, the AR-3a is definitely a better choice. Thus for the classical music lovers, there is no need to hunt for the rare AR-303a. Just be prepared to pay for or perform a lot of restoration on a 45-year-old pair of AR-3as.