Foreword / YouTube Video Review
I was loaned these from the manufacturer. I was not paid nor did I receive any other form of compensation for this review.
All my reviews are done on my own time with great care to give you all the best set of data and information I can provide in order to help you make a well-informed purchase decision. I offer this for free to all who are interested. In return, if you want to support this site please see the bottom of this review for ways you can help. It is greatly appreciated.
The review on this website is a brief overview and summary of the objective performance of this speaker.
- Bookshelf Speaker
- 2-Way Bass Reflex System with Rear Slot Port
- Tweeter: 1” Titanium Dome with Ferrofluid Neodymium Magnet
- Bass Driver: 5.25” Woven Carbon Fiber Cone with Rubber Surround
- Acoustically Transparent Cloth Grille
- Dual, 5-way Gold-plated Binding Posts, Bi-Wireable / Bi-Ampable
- Rear Slot Port
- Black bumpers
- Gold-plated Jumpers
- Finish: Satin Black or Satin White
As of this writeup MSRP is approximately $700/pair.
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:
IMPORTANT SETUP INFO:
This speaker was measured with the reference point at the tweeeter. Speaker was broken in. Grille was not used.
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 Contour Plot (normalized):
Vertical Contour Plot (normalized):
“Globe” Plots
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.
Additional Measurements
Impedance
Response Linearity
Horizontal Frequency Response:
Vertical Frequency Response:
Step Response
Group Delay
Harmonic Distortion
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.
Multitone Distortion
The following tests are conducted at (4) approximate equivalent output volumes: 70/79/87/96dB @ 1 meter. The (4) voltages listed in the legend result in these SPL values. This test signal is dense, similar to pink noise and excites the entire spectrums listed below at the same time. The test signal lasts 30 seconds. This is different than the sine wave test signal used to measure frequency response. The purpose of this distortion and compression 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) over time.
Given the test signal is similar to pink noise and exciting the entire spectrum at the same time I also include compression results, which is captured at the same time distortion is captured. Sometimes these results differ from the compression results you see above (namely with powered designs incorporating DSP-based limiting).
Note: The KLIPPEL software shows compression in the positive scale.
The test was conducted in (3) manners:
- Full bandwidth (20Hz to 20kHz)
- 80Hz to 20kHz
The reason for the two measurements is to simulate running the speaker full range vs using a high-pass filter at 80Hz. However, note: the 2nd test low frequency limit at 80Hz is a “brick wall” and doesn’t quite emulate a standard filter of 12 or 24dB/octave. But… it’s close enough to illustrate the point.
- Full bandwidth (20Hz to 20kHz)
- 80Hz to 20kHz
Parting / Random Thoughts
Subjective: The bigger brother - the T65 tower I reviewed here was more impressive to me - and I was thinking these bookshelf versions might be in the same ‘family’ in regards to tonality but they just didn’t have the same sound signature to me. The T65 was more light in the midrange but it was consistently lower from about 600Hz to about 2kHz or so. Whereas the B50 bounces around a couple times in the midrange and that threw me off in my listening sessions. Even though the overall response is about ±3dB, and acknowledging that the response being wavy is sometimes acceptable, this is a case where the switching from one octave to the next wasn’t a very pleasurable experience for my ears. At times I’d be missing snap of a snare but then have a bit of ‘forward’ sound.
Objective: Linearity is about -3.23dB / +2.36dB. This is typically pretty good for a passive speaker but as I said above, the issue for me, at least audibly, is these variances occur at different points and over different bandwidths as opposed to having, for example, a consistent rise in treble or a singular diffraction dip that might account for this frequency tolerance. You can use EQ to fix some of the response issues but there is still a directivity mismatch horizontally where the tweeter balloons out compared to the narrowing midrange around 4kHz due to - what I assume - is edge diffraction; a typical occurrence with budget-minded speakers. It does appear that one could listen slightly above the tweeter axis and potentially have a more pleasurable experience in regards to overall neutrality. In terms of output, the HD is pretty reasonable for a speaker this size - below 3% down to about 50Hz. Compression isn’t great at the highest levels but I’ve seen worse. Even the multitone is okay (when you remember that the MTON is relative to the fundamental and the increasing MTON distortion is where the response dips ~1khz). Overall, in terms of output capability it’s at least within the performance of other speakers in this size/price class and possibly a bit higher than average.
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