Foreword / YouTube Video Review
These speakers were loaned to me by their owner for review. This is the second iteration of Dennis Murphy’s popular BMR Monitor speaker.
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler. The video below has more discussion.
Information and Photos
Specs from the manufacturer can be found here.
- Tweeter: RAAL 64-10X OEM
- Midrange: Tectonic Balanced Mode Radiator 2.5”
- Woofer: SB Acoustics 6” Ceramic
- Frequency Response: 36 Hz - 20kHz (+ / - 2db) Anechoic
- Sensitivity: 86.5 dB (2.83v/1M)
- Box Alignment: Bass Reflex
- Dimensions: 20” H x 8” W x 12-1/2” D
- Weight: 32 lbs each
- Impedance: 4 Ohms
The current price is approximately $1700 or $1900 USD per pair, depending on finish and cabinet type.
CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:
The reference plane in this test is at the RAAL “tweeter”. I tested the speaker with the grille off.
Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.
CTA-2034 / SPINORAMA:
The On-axis Frequency Response (0°) is the universal starting point and in many situations it is a fair representation of the first sound to arrive at a listener’s ears.
The Listening Window is a spatial average of the nine amplitude responses in the ±10º vertical and ±30º horizontal angular range. This encompasses those listeners who sit within a typical home theater audience, as well as those who disregard the normal rules when listening alone.
The Early Reflections curve is an estimate of all single-bounce, first-reflections, in a typical listening room.
Sound Power represents all of the sounds arriving at the listening position after any number of reflections from any direction. It is the weighted rms average of all 70 measurements, with individual measurements weighted according to the portion of the spherical surface that they represent.
Sound Power Directivity Index (SPDI): In this standard the SPDI is defined as the difference between the listening window curve and the sound power curve.
Early Reflections Directivity Index (EPDI): is defined as the difference between the listening window curve and the early reflections curve. In small rooms, early reflections figure prominently in what is measured and heard in the room so this curve may provide insights into potential sound quality.
Early Reflections Breakout:
Floor bounce: average of 20º, 30º, 40º down
Ceiling bounce: average of 40º, 50º, 60º up
Front wall bounce: average of 0º, ± 10º, ± 20º, ± 30º horizontal
Side wall bounces: average of ± 40º, ± 50º, ± 60º, ± 70º, ± 80º horizontal
Rear wall bounces: average of 180º, ± 90º horizontal
Estimated In-Room Response:
In theory, with complete 360-degree anechoic data on a loudspeaker and sufficient acoustical and geometrical data on the listening room and its layout it would be possible to estimate with good precision what would be measured by an omnidirectional microphone located in the listening area of that room. By making some simplifying assumptions about the listening space, the data set described above permits a usefully accurate preview of how a given loudspeaker might perform in a typical domestic listening room. Obviously, there are no guarantees, because individual rooms can be acoustically aberrant. Sometimes rooms are excessively reflective (“live”) as happens in certain hot, humid climates, with certain styles of interior décor and in under-furnished rooms. Sometimes rooms are excessively “dead” as in other styles of décor and in some custom home theaters where acoustical treatment has been used excessively. This form of post processing is offered only as an estimate of what might happen in a domestic living space with carpet on the floor and a “normal” amount of seating, drapes and cabinetry.
For these limited circumstances it has been found that a usefully accurate Predicted In-Room (PIR) amplitude response, also known as a “room curve” is obtained by a weighted average consisting of 12 % listening window, 44 % early reflections and 44 % sound power. At very high frequencies errors can creep in because of excessive absorption, microphone directivity, and room geometry. These discrepancies are not considered to be of great importance.
Horizontal Frequency Response (0° to ±90°):
Vertical Frequency Response (0° to ±40°):
Horizontal Contour Plot (normalized):
Vertical Contour Plot (normalized):
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
Impedance Magnitude and Phase
Harmonic Distortion at 86dB @ 1m:
Harmonic Distortion at 96dB @ 1m:
Dynamic Range (Instantaneous Compression Test)
The below graphic indicates just how much SPL is lost (compression) or gained (enhancement; usually due to distortion) when the speaker is played at higher output volumes instantly via a 2.7 second logarithmic sine sweep referenced to 76dB at 1 meter. The signals are played consecutively without any additional stimulus applied. Then normalized against the 76dB result.
The tests are conducted in this fashion:
- 76dB at 1 meter (baseline; black)
- 86dB at 1 meter (red)
- 96dB at 1 meter (blue)
- 102dB at 1 meter (purple)
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components) instantaneously.
Parting / Random Thoughts
As stated in the Foreword, this written review is purposely a cliff’s notes version. No order; just some random notes from my listening. For details about the performance (objectively and subjectively) please watch the YouTube video. But a few notes:
- The wide soundstage and the openness is remarkable. It may very well be something others love; I know that is a cool effect I like to hear and it was really awesome on certain tracks which are panned hard to either side. However, this does seem to come at the cost of imaging focus. While I generally listened to these speakers on-axis, I did try towing them out (facing more into the room) and it didn’t help improve the focus (no surprise, but just addressing it for those who may wonder). With all that said, I dig the width but I’m not sure I’d trade it for the lack of focus it seems to present. I seem to be getting closer to finding that maybe 60° to 70° dispersion angle is my preference and a good sweet spot for trading off soundstage width for focus/imaging precision. This is a preference thing. There is no wrong answer here.
- Throughout my listening notes, I had written that there was a “glare” or “sharpness” in the 2-3kHz region. This was apparent on many of the tracks I listened to. Speaking for myself, the peak in the 2-3kHz region is a showstopper without EQ. Way too much “glare” in guitars and upper female vocals for me. With EQ, it’s much better.
- I tested the v1 of this speaker nearly two years ago and I back then I noted that the treble was a bit too bright. I don’t have that complaint in this version.
- The midrange is really quite nice, however, I noted in my listening sessions that I kept hearing a mild resonance in vocals. I thought it was closer to 250-300Hz but looking at the estimated in-room response, there is a slight elevation in the 300-500Hz region and I think this might have been what I was hearing.
- Due to the RAAL’s vertical directivity, the vertical listening window is pretty tight. Make sure to sit nearly dead on-axis with the tweeter vertically.
Overall a high quality speaker in terms of looks and sound. You definitely get your money’s worth.
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