Acoustic Research AR-303a Speakers

[tmallin]

For background on the new second system in which I'm using these speakers, see this post and this post, both of which are in my overall discussion of the Lyngdorf TDAI-3400. Like my primary system, this new second system in my Blue Room uses a TDAI-3400 for amplification and streaming. This second system, unlike my primary system, is also used for watching broadcast TV and streaming video services.

This is the second time I've owned the AR-303a speakers as vintage speakers. The first time around I wrote comparing their sound to the earlier-yet classic AR-3a speakers. See my "Vintage or Less Vintage: The AR-3a vs. the AR-303a" thread. The first time I used the 303a speakers in a large living room, bi-amplified by four channels of an Arcam AVR600 A/V receiver (highly rated at the time by Peter Moncrieff of International Audio Review [IAR]). The speakers were on 24-inch high stands, aimed straight ahead (no toe in) and I sat back about 10 feet from them. The first time around I had issues with forwardness/brightness in the 2 - 5 kHz region.

This time, the speakers are single-amped, single wired with Benchmark speaker cables from the Lyngdorf TDAI 3400. The speakers sit on lower 18-inch-high stands (these stools, actually), are toed in to face their respective ears, and I listen in the near field, about 50 inches from my ears to the drivers. As toed in in my set up, the center fronts of the baffles are about 62 1/4 inches apart. Thus, the subtended angle between the speakers from the listening position may be viewed as somewhat greater than the "standard" 60 degrees. However, since I have the speakers set up with the offset midrange and tweeter on the inside, the subjective separation may be somewhat reduced. My ears in my present chair are an inch or two below the tweeter level. The top center front of each speaker is 23 3/4 inches from the sidewall, 30 1/8 inches from the wall behind the speakers, and the woofer centers are about 26 inches above the floor. The Blue Room is very small, about 9 1/2 feet wide along the speaker wall by 9 feet, with an 8 1/2 foot ceiling. The room has plaster wall and ceiling construction and the floor is carpeted with thick cut-pile wall-to-wall carpeting over a thick pad. The speaker baffles are a few inches in front of the 42-inch flat screen Sony OLED TV.

Cutting to the chase, this time around not only are the bass and midrange extremely fine sounding for a vintage speaker of this cost (you can find them online these days for around $1,200 a pair asking price), but the highs are also now correctly balanced and very fine sounding as well.

I'm not sure which factors made the difference in my current vs. past reaction to the sound: biamping vs. single amping, no toe in vs. toed in, high stands vs. lower stands, ear height relative to the tweeter, far field vs. near field--or maybe a combination of two or more of these factors. But my reaction is now more in line with most of the other online and print reviews of the sound of these speakers.

As far as reviews go, I refer you to John Atkinson's Stereophile review and the attached review by Robert E. Greene done for the print version of The Absolute Sound in July 1996 but which is not available online as far as I can discover.

I can verify by adjusting my vertical seating position that Atkinson is right about needing to sit on or just below the tweeter axis to get the best high frequencies from these speakers. My current small Drexel/Heritage chair is still a bit low even though I placed a Target shelf beneath the seat cushion to raise my ear height a couple of inches. I have ordered a pair of Penny Mustard barrel chairs for this Blue Room which I should receive by mid-January and which I know from experience (I have three of these same chairs in a downstairs room already) will raise my sitting position another inch or two which should be just about right. This ear height is more crucial in my current near field listening positon, of course, for simple geometric reasons.

I hear the "roughness" REG refers to in his review but, oddly, this quality seems to diminish with proper listening axis (toed in and ear height relative to the tweeter) and near field listening. And while I hear a slight foreshortening of the depth of field compared to that from other speakers mentioned by both Atkinson and Greene, in this near-field set up, there is still enough depth and three dimensionality to satisfy, even on large-scale orchestral music.

What I now have is truly excellent vintage speaker sound. And the bass! I again find myself marveling at its depth, power, fullness, cleanness, and overall rightness. Even larger stand-mount speakers like the Harbeth 40s can't match these acoustic suspension ARs in the mid- to low-bass department.

 

[tmallin]

I am not yet using the Lyngdorf's Room Perfect in this second system. I have tried the Voicings and occasionally they can be helpful. But, as set up, the tonal balance is quite pleasing on a wide variety of material from large scale classical, to chamber music, symphonic band, classical vocal, classical choral, organ, as well as all sorts of jazz and pop.

I really don't understand why more modern speakers are not voiced this way. Most commercial material on Tidal and Qobuz, as well as CDs, is at least a bit thin on the bottom and bright on the top. Internet radio tends to be worse yet. Speakers should be full and rich on the bottom and a bit down-sloping toward the top to counteract this reality. Instead, most speakers seem balanced just the opposite: at best flat in the low end, but tilted up in response in at least the top two octaves (5,000 Hz up) if not from around 2 kHz up.

This seems to be a preference for a lot of modern listeners. The changes made to the Wharfedale Linton are a recent example. The Wharfedale designer acknowledges addressing the minor criticisms of buyers of the overall very well received Linton 85th Anniversary Edition in designing its new Super Linton. Buyers wanted to be able to place the speaker closer to the wall behind it without incurring bass boom, wanted less reticence in the midrange, and wanted a more open sound in the top end. Comparing the Klippel measurements of both speakers posted on Erin's Audio Corner, you can see how in the Super Linton the bottom two octaves of bass were rolled off a bit, the mids became more forward/less recessed, and the middle high frequencies increased by about 1 dB. Erin likes the end result, but while I might appreciate the greater dynamic ability of the low end, I don't think I'd like the changes further up. (It's easy to add dynamic capability to a bass driver if you roll off its lower octave extension--it just is not working as hard at any given frequency at any given SPL.)

The AR-303a, as I think the Atkinson review summarized, are "big-hearted" in the low end. Atkinson meant it as uncomplimentary or at best a warning to those who want more neutral sounding speakers. But I take this characteristic as a partial remedy for what ails most commercial recordings.

The Dynaco A25 vintage speakers I had in this room before the ARs were even more natural or even in overall tonal balance, lacking the "big-heartedness" of the AR's low end. The Dynacos are very easy on the ears and dynamically responsive enough for any kind of music even at considerable playback levels in this small room. Their weaknesses are purely in a slight lack of transparency and lack of bass below 50 Hz and lack of high frequency sparkle--subjectively rolling off just a bit from 5 kHz on up, I'd say. The lack of bottom and top balance each other and sound quite "right" together, however, especially since the entire range is not as transparent as the best speakers. Gordon Holt's 1969 review of these Dynaco A25 speakers in Stereophile is right on the money, as I hear them.

The midrange of the ARs seems quite natural in balance, but is not as ultimately clear and revealing as excellent modern speakers like my Watkins Generation 4 or Graham LS8/1.

The AR-303a sound is wide open and has an excellent sense of the height illusion; no miniaturized instruments and voices here. And as you turn the volume up from moderate to life-like levels, there is nothing impeding the low end from staying full and low in distortion. Neither do the upper ranges evidence any sense of strain. The sound just gets bigger and the bass more powerful sounding as you reach levels where Fletcher-Munson effects are minimized. The big 12-inch acoustic suspension woofers really deliver the goods!

Listened to in the near field as I have them, there is a considerable sense of immersion, probably from side wall reflections in my acoustically untreated room. But as the Stereophile test report shows, the lateral off-axis radiation from the AR-303a is very even and smooth up to at least 6 kHz, and above that rolls off fairly smoothly. The sidewall reflections thus blend nicely with the stronger direct near-field sound and give a nice sense of the original natural or artificial venue, even though the wrap-around effects I hear in spades from my Watkins speakers in my other acoustically treated room are substantially diminished.

 

[tmallin]

Here is a frequency response measurement taken by Robert Greene of his Acoustic Research AR-303 speakers. The AR-303 is basically the same speaker as the 303a I have except that the 303 uses only a single pair of different binding posts and thus is not biwireable or biampable. As notes to this graph he said that the room effect narrow dips in the lower frequencies are not a serious problem in audible terms and that the speakers actually sounds quite convincing. He said they are maybe not quite as uncolored as he can get out of BBC models and the Spendor A4, but still good. And the bass is good indeed without a sub. He said he could have notched out the boom down in the bass but it seemed not too important in musical terms.




From this graph you can see what I mean about the response being "big hearted" and generous in the low end, tapering down a bit in the top two octaves. This response complements many commercial recordings very well indeed.

 

[tmallin]

Making Your Sonic Presentation Sound Larger

Many music lovers and audiophiles want their home systems to present a "big" sound, as in spatially more expansive. Many mega-bucks systems can do this and this is one factor that impresses about such systems. What are the factors which make for a spatially more expansive presentation?

I believe that there are several aspects to sound which can contribute to our perception of the "size" of the presentation:

Actually large physical size and/or subtended vertical angle--very tall speakers--tend to sound vertically big, whether they are planars or cones and domes. The largest non-stretched images I ever got from non-planar speakers were from the D'Apollito array of the Legacy Audio Whispers. I have never heard speakers reproduce that aspect of space any better or even quite as good. Really life-sized musicians as if heard from close up, but never a sense of vertical stretching. The speakers sounded not like a pulsating sphere with the implied compact size, but like a pulsating ellipse or egg with real height to very vertically focused images. Those speakers were quite tall and weighed 240 pounds each with their four 15-inch compound dipole woofers apiece.

Ambiance--how much of the size, shape, and boundaries of the recording venue are portrayed. This is one area where adding subwoofers or otherwise extending the bass to the very bottom of audibility and maybe even below can help. This is actually at least as important a contribution of adding subwoofers as any actual bass extension, given the lack of 20 - 40 Hz frequencies in most actual music.

Image height/size--are instruments squashed vertically, are they life-sized in height, or are they stretched vertically? Planars often stretch image height beyond life sized. The Sanders 10e were not bad at this--just a little vertically as well as horizontally stretched. Maggies tend to be quite vertically stretched and horizontally imaging challenged in terms of focus and stability. Three-way speakers where the tweeter is on top, mid in the middle, and woofer on the bottom can often produce life-sized images, as can good D'Apollito arrangements. Two-ways can be squashed but this is mitigated by careful listening position and perhaps angling the speakers back a bit so more sound hits the ceiling.

Envelopment--how much wrap-around effect there is to the stage. Is most of the sound just between the speakers? Does the soundstage extend to the walls? Does the stage wrap around toward the listening position? When phasing effects are recorded or created in the studio, is there a sense of wrap-around of staging past your sides and to your rear or even full envelopment, as you can have with surround sound set-ups? With two speaker stereo, much of this in my experience depends on how well your listening room's first reflection areas are treated, how exactly positioned your speakers are with respect to the listening seat, and how well the drivers "speak" in phase. First-order crossovers or DSPed crossovers where all the drivers' sound arrives at the same moment greatly enhance envelopment. The Watkins and Grahams are great at this; the Watkins because of their time-aligned first-order crossover and the Grahams because there is no crossover at all until the mid-treble.

Depth of stage--the deeper, the larger the apparent sound source--the same considerations apply here as with envelopment, I find.

Near field vs far field listening. In my experience, the closer up you can listen without losing inter-driver coherence from your speakers, the larger the direct sound will appear to be. Harbeths are the best at this in my experience. The M40 series can be listened to from as close as 20 inches from drivers to ears and still not hear out the driver positions as long as your listening axis is just an inch or two below the tweeter center. You can enhance this effect somewhat by carefully increasing the distance between speaker centers to beyond 60 degrees, just being careful not to develop the dreaded "hole in the middle sound" or making the resulting sound too bright. The more the sound comes at your ears from directly to the side, the brighter the sound. You can combat this by not toeing the speakers in to aim directly at your ears, but then you will get more side wall reflections--it's a balancing act. If you don't mind the "claustrophobic" feel of such large speakers being up close and personal (I did eventually mind and that is one reason I moved on from my M40.2s), you will certainly hear very big sound indeed with fully extended bass as well and no vertically stretched images, just life-sized sound.

Another factor which can influence how large a sonic presentation seems is the degree of ceiling reflection. Few speakers intentionally engage the ceiling as a reflector, but there are a few that do and they can sound quite huge even though they are short. The old EPI 201/Epicure 20 or 20+ is one. One Burhoe module faces front, the other faces the ceiling with just a slight angle forward toward the listening area. I keep looking for a decent pair of the Epicure version to hit the used market again so I can try them in my new vintage room. More recently Burhoe is doing basically the same thing in his Direct Acoustics Silent Speaker II model with just one module and it facing the ceiling the same way.

The other company which comes to mind is Shahinian. Several of their models feature a significant portion of ceiling-facing sound. The big Diapason/Double Eagle model used to sound magnificent on classical music at AXPONA before Shahinian died and the Shahinian room was always an oasis of classical music civility and was usually packed for that reason. He would play what you wanted to hear and seemed to appreciate the offerings from attendees. The speakers are still being made.

I suppose true omnidirectional speakers qualify, but I think that with true omnis the side wall reflections detract from the presentation unless the room is either very heavily padded or unless the room is very large with the speakers placed many feet from the walls. With short speakers and a relatively high ceiling, the reflections from the ceiling are far enough from the speakers and thus late enough arriving at the listening position to tend to add spaciousness and presentation size without annoying brightness or grit.

I also believe room treatment of the type which minimizes reflections from the listening room walls through absorption can make concert hall recordings sound much larger in presentation, even with small two-way speakers like my Watkins Generation 4. Absorbing the wall reflections from a small second-venue listening room unmasks the recorded acoustics of the vast concert hall, especially with speakers like the Watkins which have time coherent crossovers and angle the sound up toward the ceiling just a bit.

Finally, and perhaps seeming to contradict the prior paragraph, speakers which can intentionally take advantage of undamped reflections from some room surfaces can create a larger presentation. Maggies and other planars can do this, as do cone and dome speakers such as the Linkwitz dipoles. One can quibble about whether such presentations tend to create more of a "they are here" feel than a "you are there" impression, but there is no doubt that the wall reflections can make the presentation seem larger.

Finally finally, keep in mind that some attempts to enlarge to apparent size of the presentation will trade the larger stage/presentation for imaging specificity and focus. You have to decide whether this trade off is worth it for you. To me, it usually is since live unamplified music generally does not produce the kind of focused images possible with many two-channel stereo set-ups, and since, on the other hand, live music heard from my preferred listening positions of fairly close up usually sounds huge and enveloping in terms of staging and overall presentation.