Acoustic Visions is a small business specializing in home theater
consulting, installation, and calibration. Owned and operated by Kyle
Richardson, Acoustic Visions offers a variety of subwoofers (both kits and
pre-finished), speakers, accessories, and complete HT systems.
The MRS-10 is the first subwoofer from the Acoustic Visions “Music Rendition
Series”. The MRS subwoofers are sealed mid-Q (about 0.7) units that are
designed to provide musical accuracy while still retaining good output and
performance for HT applications. (For those readers wanting an explanation
of the Thiele-Small Parameters - of which Q is one of the units -
here is a good article, in PDF form. The article also explains other
things about how speaker enclosures affect the response.) See also
this post in our Forum.
The MRS-10 was specifically designed for smaller size rooms, the concept
being that the shallow roll-off of the sealed subwoofer will combine with room
gain, thereby yielding usable extension into the mid 20 Hz region.
The MRS-10 cabinet is a down-firing cube measuring 13.75” square, handsomely
finished in black piano gloss, with no visible seams or edges. A nice
Acoustic Visions metal nameplate graces the front panel. The rear mounted
amplifier contains a second MRS-10 metal nameplate. The overall visual
impression of the MRS-10 is diminutive and classy.
I removed the driver to get a closer look inside the cabinet. The woofer is
secured with wood screws, and the cabinet is stuffed with Polyfill. The MDF
wall panels are ¾” thick and the enclosure is unbraced, but appears to be
The MRS-10 is supported by four 2" wooden feet, and the face of the
woofer is about 1.25” above the floor. This should work fine on most
carpeted surfaces, but deep pile carpet might interfere with the long-throw
driver. On my laminate floor, the wooden feet buzzed loudly, and the sub
wandered (moved around the floor) at high playback volumes, prompting me to use rubber furniture
feet, which worked fine. I discussed this with Kyle, and he will now include
some optional stick-on rubber bumper feet to keep the MRS-10 quiet and
secure on hard floor surfaces.
driver is manufactured by Destijl, and features a high-density
foam surround, impregnated pulp cone, a deep cast-aluminum basket,
quality push-button binding posts, and a beefy looking magnet structure. A
few of the Thiele-Small (T/S) parameters are: fs 27 Hz, Qts 0.43, Xmax 18 mm,
Vd 1.25 liter, Pmax: 300 watts.
The driver also features Adire Audio XBL2 TM technology. In essence the XBL2
topology provides a linear motor strength over the entire excursion range of
the woofer, which gives certain performance benefits. For more
information on XBL2 technology, visit
The Class AB plate amplifier is rated at 250 watts continuous, and has the
- Auto-On/On/Off Slide Switch
- Low Level L/R RCA Inputs (gold plated)
- High Level L/R Inputs
- High Level L/R Outputs (1st order high pass filter at 125 Hz)
- Low Pass Filter (40-160 Hz continuously variable)
- Phase Control (0-180 degrees continuously variable)
- Thermal, Overload, and Fuse Protection
- Detachable Power Cord
To help flatten and extend the frequency response, the amp features
progressive EQ with about 1 dB of boost at 60 Hz, rising to approximately 5
dB at 31 Hz. Below 31 Hz, a high pass filter is employed to help protect the
woofer from over-excursion. A graph showing the EQ curve and the effect of
the HPF is shown on the right.
The variable phase control offers a wider range of adjustment than a 0/180
phase switch, allowing the user to dial in the phase response of the
subwoofer with that of the main speakers. Variable phase is also very useful
for integrating dual subwoofers that will be located in different areas of
The amp layout is logical, and the rotary controls move smoothly with a
slightly heavy feel, which is nice for making fine adjustments. There is a
large heat sink which worked well to keep the amp temperature under control
during extended periods of high volume running. The auto-on circuit worked
fine and always stayed on during movies and music, even during quiet
There is no low-pass filter disable switch, so if the user operates the
MRS-10 with a Dolby Digital A/V receiver or “Pre/Pro” and digital bass
management, the low-pass filter control should be set to 160 Hz.
On the Bench
In order to determine the quasi-anechoic frequency response, the MRS-10 was
placed outside, away from any reflective structures, and measured using
ground plane techniques. Measurements were conducted with the microphone
facing the woofer, at 2 meters from the depth centerline of the subwoofer
enclosure, with the low pass filter set to 160 Hz, and the phase control set
to 0 degrees.
The TrueRTA Quick Sweep uses a short duration (about 1.5 seconds) digitally
synthesized logarithmic sine sweep. The short duration of the sweep also
makes it ideal for evaluating the dynamic output capability of the
subwoofer. FR sweeps were conducted at progressively increasing sound
pressure levels (2 dB increments) until dynamic compression was noted.
Dynamic compression is caused by exceeding the short-term linear operating
limits of the subwoofer, and is indicated when the frequency response starts
to compress and exhibit anomalies.
The MRS-10 frequency response measured
3 dB from 32 Hz - 142 Hz, and is
characterized by a plateau in 50 Hz - 90 Hz region with a falling response above
and below those points. The roll-off becomes steeper below 31 Hz, confirming
the presence of the high pass filter.
The green curve represents the maximum uncompressed dynamic output, with 104
dB in the 70 Hz - 90 Hz bandwidth, and 97 dB at 30 Hz. The next curve (purple)
stayed mostly linear, exhibiting some minor compression below 30 Hz. The
next higher curve (yellow) exhibited more obvious compression.
Harmonic distortion occurs when harmonics (multiples) of the fundamental
signal are produced due to non-linear behavior of the electrical, magnetic,
or mechanical mechanism of the driver. A subwoofer with low THD will sound
clean and distinct, especially at the deepest frequencies where distortion
harmonics are easiest to detect.
Measurements were conducted with the microphone facing the woofer, at 2
meters from the depth centerline of the subwoofer enclosure, with the low-pass filter set to 160 Hz, and the phase control set to 0 degrees. To
calculate the 1 meter test values, add 6 dB to the 2 meter reading. THD was
limited to 10% unless otherwise noted. With the exception of 22 Hz, the test
frequency spacing was 1/3 octave.
MRS-10 10% THD Test Results (Ground Plane 2 Meters):
Audio equipment reviewer Tom Nousaine calculates bandwidth linearity by
dividing the average SPL by the maximum SPL and expressing the results as a
percentage. A score of 100% means the subwoofer exhibits perfect output
linearity across the given bandwidth.
MRS-10 Bandwidth Linearity Calculations:
|20 Hz - 80 Hz
|22 Hz - 80 Hz
|25 Hz - 80 Hz
At 40 Hz and 98 dB, THD was 10%. The spectrum is
To simulate a typical user set-up, the MRS-10 was placed in the front left
corner of my 2,000 ft3 home theater room. For bass management, all speakers
were set to small with a crossover of 80 Hz. The in-room FR sweeps were
processed through the Pre/Pro with only the main speakers and the MRS-10
operating. Setting the phase to 0 degrees provided the best results in my
room. The MRS-10 gain was adjusted to obtain a good transition from the main
speakers, and to provide an optimally flat FR across the majority of the
The in-room FR was measured at three popular listening positions, all about
12 feet from the MRS-10. The three curves were then combined to create an
average response curve. The three curve average measured a very good
dB from 22 Hz - 83 Hz, graph shown below. As advertised, the MRS-10 exhibits useable extension into
the mid 20 Hz region by taking advantage of room gain in a small to mid-size
room. In a much larger room, the response would roll-off sooner, more like
the quasi-anechoic ground plane curve.
To provide a real world indication of how loud the MRS-10 can play in my
mid-size HT room, I measured some sound pressure peaks from a few
action-oriented DVDs. I used a B&K Model 2205 SPL meter (set to C-weighted
Fast) at the listening position. The sound pressures listed are straight
meter readings, with no correction factor applied.
As a guide for setting the maximum playback level, I increased the master
volume until minor distortion and compression artifacts were noted on the
deepest and most challenging scenes, and then backed off on the master
volume 2 dB to ensure a dynamic and low distortion presentation. My HT
system is calibrated to Dolby Reference Level at master volume 0.0 with the
Avia Guide to Home Theater DVD. Master volume settings are listed for
reference purposes only.
a) Lord Of The Rings – Fellowship Of The Ring (DTS-ES 6.1), Master Volume -13
I was quite surprised by how loud the MRS-10 played on certain mid-bass
passages. With source material above 30 Hz region, it displayed great
dynamics. While the MRS-10 remained well behaved on the ring drop and the
cave troll scenes, it definitely rounded off the bottom end, not providing
much infrasonic room decay.
|Sauron Ring Drop
|Sauron Death Sweep
|Sauron Helmet Falls
|Wraiths On Horseback
|Mount Doom Thunder
|Cave Troll Falls Dead
b) The Haunting (DTS-ES 6.1), Master Volume –14
The MRS-10 really pounded the room on the door knocks, which are primarily
centered in the 40 Hz - 50 Hz region. In comparison, “the cold” scene (which is
centered at 22 Hz) was almost inaudible, except for some doubling in the 40
c) Star Wars Episode II –Attack Of The Clones (DD-EX 5.1) Master Volume –13
The MRS-10 didn't falter during the demanding THX Calvalcade “exploding
globe” scene, but did omit some infrasonics. The Coruscant ship passing and
ship explosion scenes were played well, with good power and dynamics. In
comparison, the MRS-10 lacked some authority on the extremely deep speeder
On music, I found the MRS-10 to be sensitive to room placement. Corner
loaded, it tended to add a bit of weight and body to certain music notes in
the 35 Hz - 45 Hz region. Moving the MRS-10 away from the corner about 18”
eliminated this effect, and provided a more natural presentation to the
music. MRS-10 owners are encouraged to experiment with placement for the
best results on music.
a) Giant Steps - John Coltrane, Atlantic Recording Corporation, 1960
Syeeda's Song Flute features an acoustic bass solo by Paul Chambers. The
MRS-10 displayed good time coherence and kept pace perfectly with the main
b) Everything Must Go - Steely Dan, Reprise Records High Resolution DVD-A,
“Godwhacker” opens with a well recorded bass kick drum, and the MRS-10
stayed tight and focused, with no slop or overhang.
c) Underworld soundtrack - Lakeshore Records, 2003
Renholder's Now I Know contains very strong synthesized bass in the 23 Hz
region. The MRS-10 struggled with this track at higher volumes, rounding off
the deepest notes and sounding a bit wooden. It performed much better on A
Perfect Circle's "Judith" (which contains bass in the 30 Hz region), showing
good authority and dynamics.
d) A Knight's Tale soundtrack – Sony Music Entertainment, 2001
Queen's "We Will Rock You" features that famous pounding bass line. The MRS-10
separated the double hits well, with good definition.
The MRS-10 showed realistic timbre and smooth blending with the mains on the
funky electric bass guitar lines in War's "Low Rider".
I liked the way the MRS-10 easily separated the repeating kick drum and bass
guitar rhythm lines in Eric Clapton's "Further On Up The Road".
"The Boys Are Back In Town" (Thin Lizzy) is just one of those classic rock
songs that encourages you to crank it up. The MRS-10 rocked out well, with
good dynamics and realistic tympanics on the kick drum and tom strikes at
e) Monk's Dream The Thelonious Monk Quartet – Columbia Records/CBS, 1962
(Direct Digital Remaster)
Bassist John Ore anchors the title cut from this famous jazz recording. The
MRS-10 displayed good cohesiveness and nuance on the acoustic bass, drawing
the listener into the recording. Ditto for "Bright Mississippi", where the
MRS-10 nicely preserved the delicate pitch and timbre of the soaring
acoustic bass lines.
The Acoustic Visions MRS-10 definitely has a high Spousal Acceptance Factor.
It is small enough to fit inconspicuously almost anywhere in a room, and yet
it is handsome and elegant enough to match nearly any décor.
Being a sealed subwoofer, the MRS-10 has a shallow roll-off, and in smaller
rooms will take advantage of room gain and exhibit useable extension into
the mid 20 Hz region. I would not recommend this subwoofer for larger living
spaces, as it would tend to roll-off at the 30 Hz - 35 Hz region in a big room.
After experimentation with placement, I found the MRS-10 very natural
sounding on popular music, with a pleasant and non-fatiguing character. It
blends well with the main speakers, has good detail, coherence, and pitch.
The MRS-10 is a good start to the “Music Rendition Series” from Acoustic
In my mid-size room, the MRS-10 performed well on many DVDs, easily filling
the room with punchy and dynamic bass that belied its small size. While the
MRS-10 did capture the weight and body of most popular bass passages, it
can't do justice to source material below 25 Hz, and also omitted the
infrasonic decay on certain scenes. In fairness, playing extremely deep
wasn't a design goal for the MRS-10, and Acoustic Visions offers other
larger subwoofers that will easily play below 25 Hz with authority.
The MRS-10 was designed to be a versatile performer on most popular music
and movies, while retaining small dimensions. I think
Acoustic Visions has achieved that goal with the MRS-10. Consumers who place
a premium on aesthetics and size while still demanding good overall
performance will find that the MRS-10 definitely fits the bill.
- Ed Mullen -