March Audio Sointuva Bookshelf Speaker Review

  • Thursday, Jan 6, 2022
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Foreword / YouTube Video Review

This speaker was loaned to me by the manufacturer. This is an updated version of the previous design, where the notable difference from the original is now the use of the SB Acoustics Satori TW29BNWG-4 Beryllium Dome Tweeter with Waveguide (the original used a non-waveguided tweeter). The pair loaned to me were the original prototype design. Given the speaker manufacturer is located in Australia, I was willing to test these rather than have him build me a brand new pair simply for testing and then have to sell at a discounted price later for it being used.

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.

< coming soon >





Information and Photos

Some specs from the manufacturer can be found here.

2-way passive radiator design using the following components:

  • Satori TW29BNWG-4 Beryllium Dome Tweeter with Waveguide
  • Purifi PTT6.5X04-NFA-01 Midwoofer
  • Dual Purifi PTT6.5PR-NF1-01 passive radiators

Price is approximately $3500 USD for the pair, or more, depending on the finish. These are built to order and lead time is 4 weeks according to the manufacturer.

Crossover Components:

specs





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, per the manufacturer.

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.

specs

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

specs

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.

specs

Horizontal Frequency Response (0° to ±90°): specs

Vertical Frequency Response (0° to ±40°): specs

Horizontal Contour Plot (not normalized): specs

Horizontal Contour Plot (normalized): specs

Vertical Contour Plot (not normalized): specs

Vertical Contour Plot (normalized): specs

“Globe” Plots

Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left. specs


Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left. specs





Additional Measurements


On-Axis Response Linearity

specs


Impedance Magnitude and Phase


specs


Step Response

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Harmonic Distortion

Harmonic Distortion at 86dB @ 1m: specs

Harmonic Distortion at 96dB @ 1m: specs




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:

  1. 76dB at 1 meter (baseline; black)
  2. 86dB at 1 meter (red)
  3. 96dB at 1 meter (blue)
  4. 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.

specs







Parting / Random Thoughts

If you want to see a sample of the music I use for evaluating speakers subjectively, see my Spotify playlist.

I always listen to speakers before I measure them. This ensures I am not swayed by the measurements before I listen.

  • Nice extension with an F3 of 47Hz. In-room bass response should be adequate for most 2-channel enthusiasts, though, I would still use a subwoofer as I listen to a lot of content with lower bass.
  • This speaker has one of the best overall responses that I’ve seen to date with great directivity.
  • While the on-axis response shows a rising treble, I didn’t hear this as offensive. I think this is due, at least partly, to the rather narrow horizontal dispersion. The lateral reflections aren’t strong and therefore the estimated in-room response doesn’t exhibit the kind of pronounced treble a speaker with a rising treble response and wide radiation would.
  • The narrow radiation - while helping to keep the treble from sounding bright in-room - is the only underwhelming part about this speaker on paper to me. I generally prefer a speaker with a wider radiation pattern. However, when listening, I didn’t find myself having any issues with this. In fact, in many tracks, I felt the soundstage was wider than the data would have me believe. I’m not sure what the driving factor here is. Could it be the extremely smooth horizontal off-axis response? I noticed that on-axis, the soundstage didn’t seem that wide but when turning the speakers off-axis to tame the highs, the soundstage actually broadened more than I would have expected. Could this be due low crosstalk from speaker to the opposite side when listening in stereo?
  • Imaging also seemed quite good on this speaker and didn’t suffer when turning the speaker off-axis.
  • In terms of output levels, due to the average sensitivity of about 83dB @ 2.83v/1m, this speaker needs power. I am using a Parasound HINT-6 which has about 220wpc @ 4ohm and was close to maxing it out. When talking about driving a speaker like this hard you often have to worry about mechanical issues. I am happy to say that for most of my listening I had no issues with any pops or woofers bottoming out. In some instances when I would listen to rap music with bass heavy notes, I engaged the Parasound’s internal crossover and used a filter of 30Hz/24dB to limit the low bass excursion of the Sointuvas.
  • Distortion and Compression: The distortion is shockingly low. Especially for a 2-way bookshelf sized speaker with a sensitivity of 83dB. At 86dB the THD is under 0.30% down to about 50Hz. For reference, this is actually even lower than or at least on par with the JBL M2 which uses a 15-inch high-sensitivity midwoofer. At 96dB the THD rises but remains low at under 1% down to about 50Hz. This is a class leading design by distortion metrics. Additionally, the compression testing shows very good performance as well with only about 0.50dB deviation from 76dB to 102dB (above 50Hz). Again, incredibly good performance here.

When I have a speaker with so few flaws, it’s hard to talk about it. This speaker - the same as the Dutch & Dutch 8c and Kii THREE (and some others I forget at this moment) - is such a speaker. Suffice it to say, the Sointuva is a fantastic speaker with excellent directivity, incredible distortion and great linearity. The lower sensitivity might cause one to forgo them in lieu of another speaker if you are expecting to listen louder but to that I will remind you that you are most likely not going to find another speaker this size that has more output capability in the lower bass and would still likely need to purchase a subwoofer for very low bass content. If listening at modest levels and/or close to the speakers, I expect most 2-channel enthusiasts would be satisfied with the extension and output of this speaker. The Purifi midwoofer and the Satori tweeter are obviously the stars here but the integration March Audio has done with these components in a relatively small cabinet, achieving textbook directivity and class-leading distortion/compression metrics should be lauded.

As stated in the Foreword, this written review is purposely a cliff’s notes version. For more details about the performance (objectively and subjectively) please watch the YouTube video.



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