PSB Imagine T3 Tower Loudspeaker Preview

Since 1972, PSB Speakers has been part of the rich heritage that has made Canada one of the great sources of audiophile products.  Named after its founder, Paul and his wife, Sue Barton,  PSB has built up the reputation over the years of building high performance, high value speakers.  PSB recently began shipping the new flagship model in their lineup, the Imagine T3 Tower Speaker.

The Imagine T3 continues the legacy of Founder and Chief Designer, Paul Barton, who still performs the final voicing of all PSB speakers at Canada’s heralded National Research Council (NRC).  In addition to an anechoic chamber for loudspeaker measurements, the NRC is the place where so much advancement in the acoustics and psychoacoustics of loudspeakers has taken place over the years.

On paper, the Imagine T3 appears to be an impressive speaker.  PSB calls the T3 a five-way transitional design floor standing loudspeaker. The five way transitional design is a term PSB uses to describe the way the drivers are arranged.   

There are three crossover networks in the T3.  The bottom is dedicated to the bottom woofer.  The second crossover drives the bottom and top woofers and the third crossover handles the midrange and tweeter.  While the 1” titanium dome tweeter is the same as in previous models, the midbass drivers in the T3 are all new.   

Detail of the Imagine T3 Tweeter

The woofers and midrange utilize polymer coated felted fiberglass cones mated to a high temperature fiberglass voice coil. These new drivers are combined with Linkwitz-Riley 4th order crossovers that PSB claims deliver the lowest distortion and highest power handling of any speaker the company has ever made.

Paul Barton, who is both founder and chief speaker designer, says that there are two things that have been done to the drivers to reduce distortion and respond to musical transients more faithfully.  

First, a copper cap over the pole piece of the motor structure helps reduce 3rd harmonic distortion. Second, a symmetrical drive design creates a more uniform magnetic field in the motor (driver) coil.  According to PSB, this uniform magnetic field makes the cone motion more linear by reducing 2nd harmonic distortion, especially at high volume levels where the cone motion is greatest.  

The T3 features three 7” woofers in a transitional array.  In the T3’s transitional array design, all three bottom woofers produce the lowest frequencies together as a piston and each woofer has its own port. However the roll-off of each driver is different depending on its physical placement on the speaker.  The lowest woofer, (the one closest to the ground) goes up to about 100Hz then rolls off.  The next driver goes up to about 250Hz and then rolls off.  The next driver goes to about 500Hz before rolling off and is the only driver that crosses to the midrange.  The midrange then crosses to the tweeter. 

As can be seen in this design, at the very lowest frequencies, the source of the sound is very large and then as the frequencies get higher, the radiating source area gets smaller and smaller until it finally crosses over to the tweeter.  PSB says this eliminates any interference between drivers producing common frequencies for what they call “a perfect transition with uniform off-axis response.”   

The lower drivers also have a trim ring around them and the are slightly recessed in the ring. PSB says this gives them a bit of a horn-loading.  Therefore, the driver performs bigger than it actually is.  This claim is questionable as it would take a rather large horn load at bass frequencies to pull off such a feat.  

Paul specifically designed the speaker in this way to enhance the output capability of the speaker.  Using multiple, smaller woofers creates a more efficient transfer of energy into the air compared to a single larger woofer.  PSB claims that the combined volume of air that the three 7” woofers can move is larger than a comparable, single 15” woofer.    Our calculations are that the three 7” drivers would produce about 115.5 in^2 surface area (more in line with a single 12” driver) while a single 15” driver would produce 153.9 in^2.    A single 15” driver has about 33% more surface area than (3) 7" drivers.  According to the T3s specifications, it will reach down to 24 Hz.  

Using multiple, smaller woofers isn’t only about increasing its bass response.  Such a design also increases the overall sensitivity of the speaker.  The T3’s sensitivity is very good and rated at 91 dB on paper but no specifications of how this was measured were given.

Another advantage of this design, according to PSB, is that varying the positions of the woofers  will also tend to excite a broader spectrum of room resonances. By exciting a broader spectrum of resonances the T3 will tend to prevent the 'one note bass boom' that can happen with full range speakers. PSB also says that using smaller cones with large motors also makes the speaker more accurate and each cone’s piston motion becomes more accurate with a faster transient response and lower distortion.  It should be noted that loudspeakers with multiple bass drivers and ports, such as those in the T3, not only reduce distortion but can also increase the modal density and load into a room better.  

 If you’ve followed PSB over the years, you’ll note that their speaker designs tend to have a tall and slender cabinet design.  While great from an aesthetic point of view, when slender cabinets are used as bass chambers, such enclosures tend to have a ‘pipe resonance’ that can ruin bass transients and overall performance. PSB says they address this issue by using individually tuned chambers for each woofer. Each isolated chamber also has its own rear firing tuning port.  Using the supplied port plugs, you can fine-tune the T3’s in-room response in case you place the T3s in a small room or close to a wall.  But the tweaks don’t stop there.

The T3s has three sets of binding posts.  In addition to allowing you to tri-amp the speakers, the lower binding post for the bottom woofer can also be disconnected and shorted using the provided woofer shorting bar.  Disconnecting the bottom woofer creates a ‘bass trap’ or damper to further suppress room resonances.  In other words, the lower woofer becomes an active absorber.

The purpose of all these options is to provide audiophiles and home theater enthusiasts with different options to tweak the Imagine T3 to different rooms and to different musical tastes.

The Imagine T3 has three pairs of binding posts.  The lower pair binding posts can be shorted to help fine tune the speaker to the room

Over the years PSB has been a part of defining Canada’s rich audio heritage.  The new Image T3 floor standing loudspeaker looks to continue that tradition with a number of enhancements.  The Imagine T3 retails for $7499.98/pair and is available in high gloss, furniture grade black or Cherry finishes through authorized dealers.  These speakers look like a solid piece of engineering and something we'd love to get in our sound labs one day to test.

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.