The Little Speaker That Could

Andrew Chasin auditions the ProAc Studio 150 and finds out that size, in fact, doesn't matter

ProAc Studio 150 Loudspeaker
Price: US$2300
Manufactured by ProAc
Highpoint House, Riding Road, Buckingham Road Industrial Estate,
Brackley, Northamptonshire
NN13 7BE, England, Phone: 01280 700147 Fax: 01280 700148

U.S. Distributor: Modern Audio Consultants, 112 Swanhill Court,
Baltimore, MD 21208. Phone: (410) 486-5975, Fax: (410) 403-8675

Canadian Distributor: Griffin Audio, P.O. Box 733, Montreal, Quebec,
H4A 3S2, Phone: (514) 945-8245, Fax: (514) 932-0037

Ask someone to name a line of loudspeakers manufactured by ProAc, and they'll invariably answer "the Response series". This is understandable, as ProAc has effectively built its reputation for designing and building top-notch loudspeakers on the enormous success of this series (and, to a lesser degree, the Tablette series). What if I were to tell you that ProAc makes another line of speakers dubbed the Studio series which sound just as good and are built to the same high-quality standards as the Response series? Don't believe me? Then read on.

The Great Speaker Hunt

I was recently looking for a pair of loudspeakers to replace the aging Mirages in my reference system. I had about $3500 to spend so there was a large number of loudspeakers to consider. I spent months listening to everything in this price range including the Aerial Model 7, Totem Mani-2, Martin Logan Aerius and SL3, Thiel CS 2 2 - you name it, I heard it. But somehow, none of these speakers really lit my fire.

While covering the Toronto Audio Show for this magazine in September, I happened by the room hosted by Griffin Audio, the Canadian distributor of ProAc loudspeakers. Jim Griffin was demonstrating a system featuring the Tablette 50 Signature loudspeaker fronted by a Sonic Frontiers digital front end, Anthem Pre-1 preamplifier and the muy-expensive Wyetech Labs Topaz amplifier. Music played on this system had a sense of ease and naturalness that was very captivating. I stuck around this room for a while and got a chance to listen to the Response 2S partnered with the same associated components. The 2S and the Tablette 50 Signature had a definite family resemblance, but the 2S had a noticeably deeper, more extended bottom end.

After hearing the quality of reproduction of which these loudspeakers were capable, I began thinking that maybe a pair of ProAc's would fill the void in my system quite nicely. The problem with both of these loudspeakers however, is that neither will reach its true sonic potential unless coupled to very high-quality stands, and laying out $500-$600 for speaker stands was going to be tough to swallow. What I really wanted was a coherent and transparent floorstanding loudspeaker, that could go satisfyingly low in the bass, and yet still have the imaging prowess of a mini-monitor. It was becoming obvious that finding such a beast wasn't going to be easy.

A couple of weeks after the Toronto show, I bumped into Jim Griffin again at a ProAc seminar hosted by a local high-end dealer. This time, Jim had a little surprise waiting in the wings - a handsome slim-line floorstanding loudspeaker called the Studio 150. As it turned out, the Studio 150 was the surprise hit of the seminar. For the entire three hours that I was in attendance, the room containing the 150's was full of music lovers (myself included) reveling in the splendid sonics served-up by these slender transducers. The Studio 150 sounded very promising indeed. Needless to say, the Mirage's were quivering in their cabinets as I carted the Studio 150's into my listening room for audition.

Physical Assets

One thing I've come to expect from ProAc loudspeakers is a high-level of fit'n'finish, and I'm happy to say that the Studio 150 doesn't disappoint in this regard. From the well-finished Mahogany cabinetwork (Walnut, Black Ash, Cherrywood and Teak finishes are also available at no extra cost), to the four Michell rhodium binding posts and attractive crimplene grillecloths, the Studio 150 oozes quality from each of its twin flared ports. A matching plinth, finished to the same high standard, can (and should) be fastened to the bottom of the Studio 150's, this plinth being machined for the four threaded steel spikes which are supplied.

The driver complement of the Studio 150's consists of two 5" polycarbon cone bass/midrange drivers flanking a 3/4" soft-dome tweeter offset towards the inside edge of the cabinet. The bass/midrange drivers are mounted on a die-cast chassis and fitted with a phase plug, which according to ProAc, improves low-frequency output and power handling.

Impedance and sensitivity are rated at 8 Ohms and 88.5 dB/1W/1m respectively. The cabinets measure approximately 38 1/2" x 7 1/2" x 10" (H x W x D) on plinths and spikes, and weigh about 50 pounds each.

While the Studio 150's had exceptional curb appeal, in the audio business, good looks can only carry you so far. If you don't have what it takes sonically, then your days are numbered. Could the Studio 150 cut it in the listening room as well as in the show room? I intended to find out.


I'm a fan of large-scale symphonic music meaning that smallish floorstanding speakers and screaming mini-monitors rarely float my boat. I decided to put the Studio 150 to the test immediately by throwing some Mahler its way. I thought to myself, "Yeah, small speakers like these just hate Mahler". A couple of seconds into the finale of Mahler's first symphony (marked Sturmisch bewegt, and he wasn't kidding!), I realized that these speakers were troopers, and weren't about to cower in the face of adversity. The Studio 150's sailed through this immensely powerful music without so much as a squeal, honk or belch - they just sneered back as if to say "Take That!". Throughout the sonic barrage, the Studio 150's elicited rock-solid imaging, and a see-through soundstage - two characteristics which manifested themselves throughout the review period.

I recently attended a choral music concert given by the Tafelmusik Orchestra and Chamber Choir at which they performed the first of Brahms' motets Op. 79. I was completely unfamiliar with the choral music of Brahms at the time, and was quite taken by its beauty. With the sound of a live chorus very fresh in my mind, I listened to this motet as performed by the RIAS-KAMMERCHOR (Harmonia Mundi, 901591). The Studio 150's did an exemplary job of rendering the voices of the large choir as individuals rather than as one single massive voice, and they exhibited a smooth and transparent midrange that served this music very well. Although I've never been to the hall in which this recording was made, and therefore can't comment on whether the sound of the hall as reproduced by the Studio 150's was accurate, these loudspeakers bathed the singers in a reverberant acoustic space that sounded quite natural to my ears.

On recordings made in a natural acoustic space, the Studio 150's had an almost eerie ability to melt away the walls of my listening room, replacing them instead with the boundaries of the recording venue. The Studio 150's were quite adept at the disappearing-speaker trick.

The Studio 150's had incredible weight and impact for what is essentially a small loudspeaker. Malcolm Arnold's A Sussex Overture (Reference Recordings, RR-48CD) contains some pretty powerful bass drum thwacks which the Studio 150's reproduced convincingly. The 150's reproduction of low frequencies belied its relatively high -3dB rating of 55Hz.

While the 150's bottom end was deep and powerful, it had a slight tendency to lean to the warm, rich side of neutral. This small additive coloration quite possibly added to the 150's sense of low-frequency weight and scale. Frankly, I found this minor deviation from neutrality appealing on much of the music that I listened to, however, those with a system already heavily balanced to the warm end of the spectrum may find that the Studio 150's take their system too far in that direction.

Although I never considered myself much of an imaging or soundstaging freak, spending time with the Studio 150's changed that forever. On naturally-miked recordings, these speakers could lock on to an instrument or vocalist with laser precision and refuse to let go. I could easily picture the oboist dead center, and way back in the soundstage on Malcolm Arnold's A Sussex Overture. The snare drum on this recording imaged far to the left and so far back in the soundstage that it may well have been in a different time zone.

In the rhythm and pace department, the Studio 150's were champs, often causing me to wave my arms and stomp my feet uncontrollably. Now I know why this engaging quality is so revered by many Brit-o-philes.

Summing Up

Right to the point, the Studio 150 is one of the most enjoyable loudspeakers I've ever had the pleasure of listening to. While there are other loudspeakers that will do some of what the 150's do, there aren't many that present as complete a sonic package. The Studio 150's provide a smooth, transparent top end and midrange, a deep, powerful bottom end, excellent dynamics and great rhythm and pace. As a bonus, the 150's possess the ability to render a deep, expansive soundstage with pinpoint precision, and with the right program material, disappear into the sonic landscape leaving nothing but the music behind. You can't ask for much more than that.

Associated Components

Analog source was a Linn Sondek LP12, fitted with an Ittok LVII tonearm and a Linn K9 moving magnet cartridge. Digital source consisted of a Theta Data Basic II transport connected to a Theta DS Pro Progeny DAC with an XLO Type 4 digital interconnect. DAC and turntable were connected to a Conrad Johnson Premier II via a Transparent MusicLink interconnect. Amplification duties were handled by Aragon 2004 Mk.II. Amp and preamp were connected via an MIT MusicChord interconnect. Speaker cables used were Transparent Wave Plus, and Audioquest Midnight Hyperlitz.

Review Follow Up

In Volume 2, Number 1, I reviewed the ProAc Studio 150 loudspeaker and gave it high marks for its bass performance, smooth treble, excellent imaging and overall musicality. Four months later, my impressions of this wonderful little loudspeaker haven't changed a bit - if anything they've become even stronger.

The Studio 150 is truly a music lover's loudspeaker. While the 150s present a wealth of recorded detail, they are not overly analytical or ruthlessly revealing. Don't get me wrong - the 150s won't magically transform a poor quality recording into a Chesky, Mobile Fidelity or DMP, but their liquid midrange and smooth treble might just make it listenable. With the abundance of poor recordings being turned out by many of the major labels, this should work in the 150's, and the listener's, favor.

One aspect of the 150's performance that has continued to impress me is their reproduction of low frequencies. When I first got a look at their low-frequency driver complement (two five inch mid/bass drivers), I assumed that they would sound thin and bright and wouldn't do justice to the large-scale symphonic music of which I'm so fond. Wrong! The 150s sound much bigger than they look, and their bottom-end performance continues to belie their driver and cabinet dimensions. With extensive break-in, and the addition of a pair of Echo Busters' Bass Busters in my room's corners, the bottom end of the 150s improved even further and, on the right recordings, could approach the weight and heft of much larger loudspeakers.

The one obvious advantage that the 150's two smaller mid/bass drivers have over one larger driver, is that their excursions can be more easily controlled, resulting in better transient response and less overhang at low frequencies. This, no doubt, contributed to the 150's tight, tuneful bottom-end that's given me much enjoyment over the past four months. If you want to know what I'm talking about, just pop Christian McBride's excellent Gettin' To It in your CD player, cue up Night Train, and enjoy the ride.

Those inevitable audiophile cravings for pinpoint imaging and wide, deep soundstages are well satisfied by the 150s. On My Funny Valentine from The Lynne Arriale Trio's The Eyes Have It, I could literally see Arriale's fingers as they caressed the keyboard. Finger and hand movements could easily be tracked as they traversed the keyboard from left to right and back again. The many interesting guitar and percussion sounds employed on Cassandra Wilson's New Moon Daughter, were placed with unwavering precision by the 150s, heightening the illusion of real musicians performing in their designated stage locations.

The 150's portrayal of depth varied from recording to recording, as you'd expect from a speaker accurately rendering the recorded acoustic. This is in contrast to some other loudspeakers I've heard, which gave the impression of depth on every recording, from heavily processed studio efforts to minimally-miked recordings in a real acoustic space. Such loudspeakers create, rather than recreate, this sense of depth and are not faithful to the original event. On recordings containing a lot of depth information, the 150s did an excellent job of recreating it. On those that contained little, or no, depth information, the recording's flat two-dimensional soundstage was, again, faithfully reproduced.

The 150s were very revealing of changes in loudspeaker cables, and handily resolved the differences between the Audioquest Midnight Hyperlitz and Transparent Audio MusicWave Plus loudspeaker cables used in this issue's cable reviews.

When all is said and done, the one true metric of a great loudspeaker is how much you look forward to listening to them after a hard day at work. Using this measuring system, the 150s scored very high indeed. Day in and day out, the 150s were steadfast in their ability to bring considerable musical enjoyment to my life, and that, dear readers, is what this hobby is all about.

Final Thoughts

Over the past four months of listening, I've heard nothing to give me cause to retract my past hearty endorsements of the ProAc Studio 150s. The 150 is yet another great sounding, well-engineered loudspeaker from the pen of Stewart Tyler, and deserves to be on the short list of anyone in the market for a speaker in the $2500-$4000 range.

-- Andrew Chasin