Foreword / YouTube Video Review
I purchased these speakers myself to review with funds from Patreon/PayPal/Affiliate Link revenue. If you’d like to help in this regard please see the “support” section at the bottom of this review. Thanks!
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
Manufacturer’s information can be found here.
Approximate retail price for these is $299/pair USD.
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 tweeter.
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):
“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
Response Linearity
Impedance Magnitude and Phase
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.
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.
For information on how to read the below data, watch this video:
- Full bandwidth (20Hz to 20kHz)
- 80Hz to 20kHz
SPINORAMA with Grille On
Parting / Random Thoughts
As stated in the Foreword, this written review is purposely a cliff’s notes version. For details about the performance (objectively and subjectively) please watch the YouTube video. But a couple quick notes based on my listening and what I see in the data:
This speaker shares a lot of similarities with the Jamo S803 I reviewed here. It has a midbass bump that isn’t displeasing but paired with the rising response above about 600Hz, what you wind up with is lack of midrange clarity and hollowness and instead get a very treble-heavy sound. I tried turning these speakers out by about 30° to tame the rising midrange/treble but thanks to the diffraction effects from the baffle and the tweeter “waveguide”, the nonlinearity was still too much and the sound was still far from what I find good.
Frankly, the overall performance is not much better than the much cheaper Jamo S803, either. And in some ways actually worse. Not to say that is a good thing for the Jamo S803. What you are paying for with this speaker relative to the S 803 is nicer design/aesthetic. At least in my opinion, this speaker just looks cooler. The C93 II will not take well to equalization so you won’t be able to get it to sound ideal (whatever you deem that to be; sans it being this particular speaker’s sound). Another common retort is “yes, but they’re cheap”. Trust me, I understand the need to find a speaker that is cost-efficient. This is not one of those. The Emotiva B1+ is approximately $250/pair and is a better performer in every way. In quality of sound, from linearity/accuracy of response, soundstage width/depth and output capability.
If you own these speakers and are thinking “dude, you’re wrong, these are great” then I encourage you to find speakers that have a more neutral character to them and give an honest attempt at demoing both side by side. Statistically speaking, you will likely prefer the more neutral speaker. If your goal is to get as much hi-fi or accuracy for your dollar, to hear what the media itself is or what the movie should sound like, then these speakers just are not up to the task based on their extreme non-linear response.
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