AR3a and AR-5 Spectral Balance

[Steve F]

Suffice to say, the original AR speakers certainly elicited more than their share of controversial opinions. Many consumers and reviewers considered them to represent the very height of engineering excellence, accuracy, and uncolored, natural sound. But there was also the “anti-AR” crowd, who thought the speakers were dull, and lacking sparkle. This group would concede AR’s outstanding bass, but criticized them for their low efficiency and what they felt was a depressed high end.

The AR-3a has always been the favorite target of the anti-AR faction. “Too much bass,” “The tweeter level can’t be brought up to match the woofer,” “It needs a big, expensive amp to drive it,” etc. This criticism reached its public zenith with the infamous Consumer Reports review. (It’s fascinating, however, to note AR’s understated and classy response to this review, in sharp contrast to another well-known Massachusetts speaker manufacturer’s highly publicized, wildly histrionic reaction to the negative review of their “revolutionary” speaker.)

My feeling is that most of the criticism of the 3a came about because of professional envy, and the natural tendency of human nature to cast aspersions at the acknowledged leader in an effort to make up for one’s own shortcomings. The AR-3 and 3a speakers, from 1958-1972, were simply the industry performance leaders in virtually every objective, measurable, quantifiable basis of comparison that existed.

Yet there is an undercurrent of grudging favorable sentiment among the naysayers towards the AR-5. I have noted this recurring theme in the 35 years I’ve been following AR’s product development and marketing activities. Many of the same industry luminaries who have expressed derisive comments to me about the 3a have also said such things as “…but the 5 was actually a very good-sounding speaker. Better overall balance. The tweeter is not overwhelmed by the woofer the way it is in the 3a.” I have heard this many times from many people over the years. Even High Fidelity Magazine’s review of the 5 intimated a similar point of view: “…sometimes sounded tighter…more ‘immediate’ than the 3a…”

I’m curious if any other Forum members, especially the, ah-hem, “veteran” members, have experienced similar reaction to the AR-5 from non-AR aficionados.

BTW, the “woofer level” relative to the tweeter was not any higher in the 3a than it was in the 5, despite what critics might have said. The 3a’s bass extension was considerably deeper than the 5’s and the psycho-acoustic effects of deep bass on perceived midrange and high-frequency clarity come into play when comparing the two speakers. But that’s an entirely different subject…

Steve F

[ar_pro]

Steve - My guess is that anyone who was critical of the 3a's bass response or spectral balance, voiced "approval" of the 5 in a disingenuous effort to support their argument against the 3a. I also believe that given the opportunity for a free pair of AR loudspeakers, each and every critic would have chosen two from the 3a pile, and left the stack of 5's untouched. The Model 5 was a great loudspeaker - a definite improvement over the 2ax (another great loudspeaker), and perhaps the better choice in a smaller room, or when driven by a less-powerful amplifier. It's entirely possible that legitimate criticism of the 3a can be addressed by improving the acoustic signature and size of the listening room, and by providing well-regulated and adequate amplifier power - that is: AR3a + bigger room + better amp = wonderful sound!

[Guest dogmeninreno]

>Steve - My guess is that anyone who was critical of the 3a's

>bass response or spectral balance, voiced "approval" of the

>5 in a disingenuous effort to support their argument against

>the 3a. I also believe that given the opportunity for a free

>pair of AR loudspeakers, each and every critic would have

>chosen two from the 3a pile, and left the stack of 5's

>untouched. The Model 5 was a great loudspeaker - a definite

>improvement over the 2ax (another great loudspeaker), and

>perhaps the better choice in a smaller room, or when driven

>by a less-powerful amplifier. It's entirely possible that

>legitimate criticism of the 3a can be addressed by improving

>the acoustic signature and size of the listening room, and

>by providing well-regulated and adequate amplifier power -

>that is: AR3a + bigger room + better amp = wonderful sound!

I often wonder if the people that are critical of the 3a ever thought of using stands? Big difference!!

[tysontom]

>Suffice to say, the original AR speakers certainly elicited

>more than their share of controversial opinions. Many

>consumers and reviewers considered them to represent the

>very height of engineering excellence, accuracy, and

>uncolored, natural sound. But there was also the “anti-AR”

>crowd, who thought the speakers were dull, and lacking

>sparkle. This group would concede AR’s outstanding bass, but

>criticized them for their low efficiency and what they felt

>was a depressed high end.

>

This is certainly correct to say that AR speakers "elicited more than their share of controversial opinions." Especially considering that AR was so successful during this period, it's easy to understand why there was so much diversity in opinion. A lot of the "anti-AR" sentiment also came from dealers who disagreed with AR's seemingly arrogant-marketing strategy at the time; of course, much criticism came from staunch-competitive pressure of the day, with some notable speaker companies "enabling" non-AR dealers with anti-AR rhetoric. I used to see this all the time.

>The AR-3a has always been the favorite target of the anti-AR

>faction. “Too much bass,” “The tweeter level can’t be

>brought up to match the woofer,” “It needs a big, expensive

>amp to drive it,” etc. This criticism reached its public

>zenith with the infamous Consumer Reports review. (It’s

>fascinating, however, to note AR’s understated and classy

>response to this review, in sharp contrast to another

>well-known Massachusetts speaker manufacturer’s highly

>publicized, wildly histrionic reaction to the negative

>review of their “revolutionary” speaker.)

>

There was quite a lot of criticism of the AR-3a regarding the output of the tweeter, relative to the woofer, with some testers stating (correctly) that the output of the tweeter could not exactly match the woofer, even with the level control turned all the way to maximum. To understand why AR did not design the AR-3a (and other AR speakers) to have virtually flat on-axis response is to understand compromises necessary to achieve broad power response. The response characteristics of the 3/4-inch hard-dome tweeter were designed to achieve very wide off-axis response, somewhat at the expense of sensitivity. Because of available technology and materials of the time, the hard-dome tweeter with notched-plate foam suspension was considered to offer the broadest dispersion at the highest frequencies of any available tweeter (note that even the AR-11 3/4-inch tweeter, while more sensitive, does not respond quite as well off axis as the AR-3a tweeter). This very broad dispersion was considered integral to good spectral balance in the home-listening environment. For this reason, a speaker with proper spectral balance will generally sound more natural in a normal listening environment than a speaker with flat on-axis response but compromised acoustic-power response. This is based on the assumption that one listens well back in the reverberant sound field, which affords a natural combination of reflected and direct sound, with the highest ratio of sound coming from reflected surfaces. Interestingly, the AR-LST was designed to overcome any shortcomings of the AR-3a with respect to sloping response. The recording industry, tired of existing monitor speakers, wanted AR-3a-type accuracy but with flat on- and off-axis response and much-greater power-handling capability. The needs of the recording studio or concert-hall sound reinforcement are very different from those of a home-listening environment, and those needs were met with the AR-LST. It is also for this reason that proper mounting of an AR-LST is more critical for best sound than for an AR-3a.

Smooth acoustic-power response in the reverberant field is what makes an AR-3a sound so natural and life-like in most listening rooms. Another consideration, and one with considerable debate, in favor of slightly rolled-off high-end response, is that sound in a concert hall is definitely rolled off at the highest frequencies. However, critics of the sloped on-axis response generally made this generalization while listening at point-blank range. And compared with some speakers with flat on-axis response, the AR-3a (like many AR speakers of the era) does definitely sound reticent. But this reticence is perhaps more natural, and closer to the original sound. Today, of course, loudspeaker designers can circumvent the shortcomings of past years with respect to frequency response and sensitivity, and so forth. But today's designers tend to address the issues of "imaging," and do not always look for the widest dispersion as in the days of the AR-3a speaker. Brighter and more "focused" is what is often heard, but in comparison to the original sound source, there is still controversy about what is more accurate.

>My feeling is that most of the criticism of the 3a came

>about because of professional envy, and the natural tendency

>of human nature to cast aspersions at the acknowledged

>leader in an effort to make up for one’s own shortcomings.

>The AR-3 and 3a speakers, from 1958-1972, were simply the

>industry performance leaders in virtually every objective,

>measurable, quantifiable basis of comparison that existed.

>

>Yet there is an undercurrent of grudging favorable sentiment

>among the naysayers towards the AR-5. I have noted this

>recurring theme in the 35 years I’ve been following AR’s

>product development and marketing activities. Many of the

>same industry luminaries who have expressed derisive

>comments to me about the 3a have also said such things as

>“…but the 5 was actually a very good-sounding speaker.

>Better overall balance. The tweeter is not overwhelmed by

>the woofer the way it is in the 3a.” I have heard this many

>times from many people over the years. Even High Fidelity

>Magazine’s review of the 5 intimated a similar point of

>view: “…sometimes sounded tighter…more ‘immediate’ than the

>3a…”

>

>I’m curious if any other Forum members, especially the,

>ah-hem, “veteran” members, have experienced similar reaction

>to the AR-5 from non-AR aficionados.

>

The AR-5 -- and even the AR-2ax -- were frequently stated to sound better "balanced" in the treble and bass than the AR-3a. A lot of this reaction was due to the extended bass response of the AR-3a woofer, and the effect the additional output at the lowest octave had on the apparent balance. Consider this, too, that less bass output at lowest octaves relates to "thinner" or dryer (vs. "warmer") overall sound balance. Also, the "thinner" the sound, all things equal, the brighter the speaker will appear to sound. This is perhaps part of this illusion of sound difference. This is what Steve F is essentially saying below.

>BTW, the “woofer level” relative to the tweeter was not any

>higher in the 3a than it was in the 5, despite what critics

>might have said. The 3a’s bass extension was considerably

>deeper than the 5’s and the psycho-acoustic effects of deep

>bass on perceived midrange and high-frequency clarity come

>into play when comparing the two speakers. But that’s an

>entirely different subject…

>

>Steve F

--Tom Tyson

[ar_pro]

Yes...a HUGE difference. I once owned 2 pairs of AR3a systems, placed on their sides, and stacked two-high (tweeters facing out) - kind of like those stacked Advents that "Absolute Sound" made famous. I used two pairs of the stands that were designed for the 10pi & 11 speakers, placed side-to-side, with excellent results in a large room!

[Steve F]

>My guess is that anyone who was critical of the 3a's

>bass response or spectral balance, voiced "approval" of the

>5 in a disingenuous effort to support their argument against

>the 3a. I also believe that given the opportunity for a free

>pair of AR loudspeakers, each and every critic would have

>chosen two from the 3a pile, and left the stack of 5's

>untouched.

This is spot on. I agree completely.

Steve F.

[tysontom]

>Yes...a HUGE difference. I once owned 2 pairs of AR3a

>systems, placed on their sides, and stacked two-high

>(tweeters facing out) - kind of like those stacked Advents

>that "Absolute Sound" made famous. I used two pairs of the

>stands that were designed for the 10pi & 11 speakers, placed

>side-to-side, with excellent results in a large room!

The "stacked-Advents" idea worked very well, as did stacked AR-3a's, AR-11's, even LST's. The idea of putting the tweeters adjacent to each another with the woofers at the top and bottom, seemed to work better than putting the woofers together.

One reason to separate the woofers, rather than to have them in close proximity, is the issue of mutual-radiation impedance, in which the output of the bass is elevated -- relative to the midrange and treble -- by approximately 3 dB down to resonance, but no increase or extension in deep-bass output. This increase, relative to the midrange/treble, is due to the interaction of each woofer in such close proximity, and can give the setup a warmer sound. But with one speaker inverted, the end-result was the illusion of a larger sound source and greater sense of power, etc.

--Tom Tyson