Boston Acoustics A360 Floorstanding Speaker Review

Boston Acoustics A360 Tower Speaker Introduction

Since its humble beginnings in 1979, Boston Acoustics has focused on providing good sounding systems at moderate prices.  Considering they have been in business for over three decades, they must have gotten something right.  The Boston Acoustics A360 Tower is a 3-way good-looking loudspeaker representing their current mid-level offering at a relatively affordable price ($800/pr).  In this review, we will take a deeper look and listen to see how the A360 performs.  This is the first Audioholics review to implement our Loudspeaker Measurement Standard so you will get a full picture of objective performance.

Have you ever seen a loudspeaker disappear?  It is common audiophile snobbery to talk about a loudspeaker disappearing into a room, but I am pretty sure they are talking about not being able to figure out where the loudspeaker is with their eyes closed.  In the case of the A360 in the right lighting, the super shiny piano black finish has reflective properties that blur the edge of reality.  I am guessing that the matte leather grain textured top and speaker grilles are there so that people don't just walk into the loudspeaker akin to a bird hitting a closed window.  With the slim cabinet profile and beautiful finish, most purveyors of in-TV speaker technology will not gripe about the A360’s residence in their home, especially considering the speaker’s aptitude for near wall placement.  As with any long-term investment, beauty is fleeting; it is the heart and soul that carry the most weight. Let’s investigate.

Boston Acoustics A360 Design Overview

Built on a petite 8 ¼” wide by 42” tall frame, the 4-driver 3-way A360 tower loudspeaker hits a sweet spot by providing sizeable dynamic range and surprising bass response without being beastly.  Starting at the top and working our way down, the faux leather textured hardboard top and back provides a contrast and point of reference from the rest of the glossy piano black finish. A black magnetic mesh speaker cover veils the stark contrast of white loudspeaker drivers on a black baffle.  Below the bottom woofer, the cabinet juts out a little so that the speaker cover profile is aligned with the cabinet providing a little more material in the bottom half of the baffle.  The covered front of the cabinet has a lazy parabolic shape that is a nice visual touch.  Analogies aside, a rear firing 2.5” diameter port serves to enhance the lower registers. As was the tradition many years ago in a far away land, tiny feet jutting a few inches from the base function as a form of beauty that ultimately inhibits usefulness.  If these feet are not on solid ground or augmented with spikes, the entire structure is prone to toppling.  Although it lacks some of the beauty of exotic woods and wild designs, the A360s sit pretty in most spaces.

 

Since it’s often what is on the inside that counts, the loudspeaker cover was stripped followed by the 4 Boston Acoustics proprietary drivers revealing the guts of the A360.  The cabinet construction is a minimum of ¾” medium density fiberboard on all sides with adequate internal bracing including a diagonal panel spanning from the bottom back to a few inches below the bottom woofer.  The midrange has a separate chamber isolated by a thick cardboard tube.  The midrange chamber and main cabinet have purposely placed polyfill.  A strange circular reinforcement disc is glued to the inside top of the cabinet.  This is either there to help the cabinet pass the knuckle wrap test or to damp vibrations.  The bass reflex cabinet is tuned to approximately 35Hz by way of a 6 inch long by 2 1/2 inch diameter rear port which is flared on the outside only.  The overall cabinet weight with drivers installed is a rather average 44 pounds.  The loudspeaker is a true 3-way loudspeaker with a 20-component crossover transitioning from the woofers to midrange at 800Hz and the midrange to tweeter at 2.7khz.  Boston Acoustics appeared to use a mixture of polypropylene and electrolytic capacitors as well as air and iron core inductors.  Since I didn’t reverse engineer the crossover, I have to assume the right types of crossover components were used in critical places.

 

 A360 Crossover

Boston Acoustics A360 Drivers

The 3 ½ “ midrange and 6 ½ “ woofers are made from a ceramic and glass fiber polymer material.  The woofers have, what Boston Acoustics calls, Deep Channel Design (DCD) magnet structures providing a driver geometry allowing more voice coil travel without bottoming out.  The drivers are metal stamped baskets with standard ceramic magnets.  The magnet structure and spider appear to have good build quality.  The conical shaped dust cap on the midrange and woofers is not a genuine phase plug as it is glued to the cone material.  Phase plugs in general are used to reduce cancellations at higher frequencies.  The phase plug fashioned dust caps used in the A360s provide a modern attractive touch and meet the design goals for the driver.  The tweeter is a 1-inch Kortec soft dome tweeter.

Editorial Note From Steve Feinstein on Kortec:

The tweeter in the Boston Acoustics speaker is a treated cloth, with extra damping on the underside surface. This makes it a very well-behaved tweeter, pistonic but not ‘ringy.’

The baffle configuration hosts a traditional three-way alignment with the tweeter at the top of the cabinet with the midrange and woofers below.

Boston Acoustics A360 Drivers

Set-Up

I’ve never been too interested in reading about the unboxing process so I’ll spare you too much detail.  As you might imagine, I received the A360s in boxes with Styrofoam at the top and bottom of the box.  The A360s base sits on a ¼” piece of fiberboard for added rigidity.  Intuitively, I would suspect that this configuration is sufficient to protect the loudspeakers from damage.  As I’ve learned the hard way, package delivery services are not as careful with packages as we would like.  I’m not really sure how it happened, but one of the dainty plastic outriggers was decimated to a nub.  Considering the relatively unstable base of the A360 with two working feet, the broken plastic foot was detrimental to the A360s balance.  Luckily, a light bulb went off and I determined I could shim the broken side to prevent any accidents. 

Boston A360 Terminal Cup

The A360’s had those annoying plastic plugs inserted into the back of the binding posts.  But, I was able to remove them with a small flathead screwdriver so I could insert my banana terminated speaker cables. 

Boston Acoustics A360 Sound Quality Tests

 

Listening Environment for testing the Boston A360’s

Listening Environment

This is a rather large 24’ x 20’ great room with hardwood floors throughout.  The room itself is not acoustically treated.  A 12’ x 10’ area rug with thick foam padding are between the loudspeakers and listening position.  This space is pretty reflective but has worked very well for my reference open baffle dipole loudspeakers.  Traditional loudspeakers have a tendency to sound a little harsh in the high frequency range due to reflections, but reducing the listening distance reduces this effect.  The system signal chain for testing the A360s was an Oppo BDP-105 connected directly to an ATI AT6012 amplifier using unbalanced connections.  The volume control in the BDP-105 was used for all listening impressions.  For high-resolution music sessions, a MacBook Pro running Audirvana was connected to the BDP-105.  The speakers were approximately 8 feet apart and just slightly toed in.  I found listening 10-15 degrees off axis was much more enjoyable because the treble was a little too much for me directly on-axis.

Listening Tests

These listening tests were conducted in the mentioned listening environments without any form of room correction or high-pass filter for music.

Dave Brubeck Quartet – Take Five
This track is legendary and for good reason.  On the right system, it sounds quite natural and easily characterizes a loudspeaker.  Firing it up on the A360s resulted in very precise imaging with a fair amount of depth.  It wasn’t hard to place Paul Desmond on the sax slightly left of center with Dave Brubeck’s piano off behind the right speaker.  While the bass and toms sounded pretty natural, the snare was artificially hot.  The sax was also a little laid back compared to other systems I’ve heard this recording on.  Even though it was not as close to a live performance as I’ve heard in other systems, it didn’t make me want to turn it down either.   

Angus and Julia Stone – Draw Your Swords
Since the response of the A360s does not lean toward what I would call natural due to the recessed midrange and low treble, I decided to try a well-engineered recording.  The processing of the piano in this recording can only be described as ethereal as it floats around in a way that almost confuses the brain.  The vocal processing creates a solid image in the center and then seems to decay slightly slower in the left speaker.  The Boston Acoustics did a nice job creating the soundstage on this recording.  Placed 1 ½’ to 2’ from the rear wall, the A360s bass response digs deep for a speaker of its size.  The bass response reminds me of a pair of custom speakers using four Scan-Speak revelator drivers costing over $200 per driver.  The treble sounded a little bright on the overtones in this recording.

Yeah Yeah Yeahs - Maps
I have a collection of music that spans quite a few genres, many titles of which I miss because they do not mesh well with most systems I come in contact with.  The A360s are, in my opinion, not very aggressive in the midrange.  Since the majority of popular music is mixed down in a way that sounds harsh on systems that are closer to linear in the midrange, I’ve resorted to trading some of the fun for improved quality recordings.  The Boston Acoustics definitely have a warmth and a high frequency bump that is agreeable to the world that isn’t quite as pretentious about sound.  To confirm this, I had a few guests listen to the A360s and most enjoyed them much more than expected.  This song falls into that realm of poor recordings but the kick drum is simply fun and really does sound that way with the A360s.  I can crank this song and my ears are not too upset about it!

Tortoise – The Suspension Bridge at Iguazu Falls
I have no idea why it took me so long to find this album.  This song is enjoyable and has all of the elements of a good test track.  Deep bass, focused imaging, depth and dynamic range come together in a track you can just sit back and relax to.  Out of everything I listened to on the Boston Acoustics, this track was by far the most pleasurable listening experience of the bunch.  There is a point at which the electric guitar reverb causes a nice deep soundstage that the A360s easily reproduce.

Hi-Res: Cat Stevens – Father and Son
Do you believe in the merits of 24-bit 192kHz recordings from old masters?  Well, either way I have a copy of Cat Stevens Tea for the Tillerman and like the way it sounds.  Father and son had a nice bottom end and extremely clear vocals on the Bostons.  The top end is a little bit bright when the music comes to a peak, but nothing that I could not live with.

Blu-Ray:  Loopers
What can I say, I’m a sucker for time travel and this movie doesn’t avoid the paradox of meeting yourself in a different timeline.  A unique plotline and highflying action provides a pretty fun torture test for loudspeakers.  This disc has very clear dialog, extensively exercises all channels and incorporates some nice multichannel scores.  The action scenes were rendered very well by the A360s. The tonal colorations of and ability to produce adequate SPL provided an enjoyable movie watching experience.  One note here is that these are not very sensitive speakers so you may need significantly more amplifier power than the manufacturer’s sensitivity rating suggests. 

Boston Acoustics A360 Measurements and Analysis

The measurements were conducted in conformance with Audioholics Loudspeaker Measurements Standard

 

Boston Acoustics A360 On-Axis Frequency Response

The on-axis frequency response of the A360 was conducted with the measurement microphone at 2 meters with a 2.83V excitation signal.  The results are scaled to 1 meter mathematically.  The manufacturer rates this loudspeaker’s sensitivity as 89dB at 1 meter with a 2.8V input.  Audioholics measures sensitivity as the average sound pressure level (SPL) from 300 to 3kHz.  The A360 Audioholics rated sensitivity is abysmally low at 82.7dB because there is a significant dip in frequency response from 300Hz to 3kHz for the A360.  Compared to an average loudspeaker with a sensitivity rating in the 87-89dB efficiency range, the Boston Acoustics require four times as much power to reach the same average sound pressure level from 300Hz to 3kHz.  Listening tests clearly confirm that the output of the A360 using quasi-anechoic sensitivity measurement techniques is not close to the manufacturer’s rating.  The manufacturer may have rated the A360 sensitivity in room. The frequency response dip centered around 3kHz contributes to the laid back response described in the listening impressions section.  The measurement technique used above involves removing all of the effects of a room.  The in-room bass response with the A360s placed 1.5’ to 2’ from the rear wall is subjectively the loudspeaker’s strong point.

 

Boston Acoustics A360 Listening Window

The listening window response for the A360 is conducted with a 2.83V input signal at 2 meters from 7 locations.  The measurement provides a picture of how the loudspeaker performs from seating locations that are not directly on axis with the speaker.  The top curve is the average of the other positions and provides an average of how the speaker performs throughout the listening area.  Subjectively, the off-axis response within the listening window area is pretty uniform.

 

Boston Acoustics A360 Polar Response

The polar response graph shows how a loudspeaker performs at various angles.  The polar response graph above is generated by measuring a loudspeaker at 7.5 degree intervals around a circle on the tweeter axis from 2 meters.  The A360 has relatively uniform directivity from 0-30 degrees.  As a listener approaches 60 degrees severe aberrations in the frequency response become increasingly apparent at high frequencies. 

 

Boston Acoustics A360 Impedance

The impedance of the A360 remains above the IEC 8 ohm minimum threshold of 6.4 Ohms throughout the entire audio band.  At approximately 1kHz, the loudspeaker reaches a minimum impedance of approximately 6.5 Ohms.  The impedance graph above indicates the port tuning frequency is at approximately 35Hz.

 

Boston Acoustics A360 Harmonic Distortion

The harmonic distortion graph was generated using a 90dB stepped sinusoid sweep measured at 2 meters.  The above harmonic distortion graph and cumulative spectral decay graph shown below indicate some sort of resonance at approximately 1.5kHz.  Maybe this is what that interesting circular disc is meant to tame!  Although this is present, it is not something to obsess over. 

 

Boston Acoustics A360 Cumulative Spectral Decay

Cumulative spectral decay is derived from the impulse response measurement made with a 90dB excitation signal at 2 meters.  The cumulative spectral decay shows how sound at various frequencies dies out as a function of time.  It is important to note that the left most ridge is not valid and is a product of the measurement technique. 

 

Boston Acoustics A360 Group Delay

The group delay graph shows the rate of change of the slope of a loudspeaker’s phase.  As a rule of thumb, values below 1.6ms in the mid to high frequencies will likely not effect perception of sound quality.  Increasing group delay in the low frequencies is not as objectionable as it is in the mid to high frequency ranges. 

Boston Acoustics A360 Conclusion

The Boston Acoustics A360 loudspeakers are well built and look good at $800/pair.  High quality parts are used in the cabinet construction and the drivers are decent quality.  I was disappointed with the actual sensitivity compared to the manufacturer’s stated sensitivity.  I felt like a 100WPC amplifier couldn’t get the A360s very loud.  This low sensitivity is mainly due to the midrange and low treble being somewhat recessed compared to the rest of the frequency range.  That recessed midrange reduces listening fatigue allowing for a listen-all-day type of response.  The tradeoff is that some recordings do not sound very natural.  The bass response is excellent given the size and footprint.  An upright bass sounds pretty convincing when the speaker is properly placed with a little room gain. 

I envision that Boston Acoustics designed this speaker to please the masses and I think it is excellent in that regard. 

 

Boston Acoustics A360 Scorecard
MSRP: $800/ pair

 

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Build Quality
Appearance
Treble Extension
Treble Smoothness
Midrange Accuracy
Bass Extension
Bass Accuracy
Dynamic Range
Performance
Value