Polk Monitor XT30 Center Channel Speaker Review

  • Saturday, Jan 8, 2022
blog-image

Foreword / YouTube Video Review

I purchased all of the Polk Monitor XT speakers for evaluation as an entire model lineup (except the Atmos speaker). I was able to do so out of my own funds with support from my Patrons and donations. If you’d like to help out with future reviews please see the bottom of this review.

Due to the overwhelming task of reviewing all of these at the same time I am not providing subjective evaluation in this review. I also used a stock photo in this review to save me a little time.

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 with respect to the technical merits and subjective notes I had during my listening sessions.



For help understanding the data, I encourage you to watch this video which discusses the implications of (some of) the data shown below:





Information and Photos

Some specs from the manufacturer can be found here.

  • Width: 19.9” (48.3 cm)
  • Height: 6.50” (16.6 cm)
  • Depth: 8.13” (20.7 cm)
  • Weight: 13lbs (5.9 kg)
  • Front Array Driver Complement:
    • (1) 1” (2.54 cm) Terylene Dome Tweeter
    • (2) 5-¼” Bi-laminate Paper Woofers
  • Enclosure Type: Rear port
  • Lower and Upper -3dB Limits: 77 Hz → 26,000 Hz
  • Sensitivity (1 watt @ 1 meter): 89dB SPL
  • Total Frequency Response: 55 Hz → 40,000 Hz
  • Recommended Amplifier Power Per Channel: 30 watts → 200 watts
  • Tweeter/Midrange Crossover Frequency: 2500 Hz
  • Inputs: Single nickel-plated 5-way binding posts

Price is approximately $200 USD for the single center channel. If you are interested in purchasing this speaker, please consider using the following affiliate link which earns me a small commission at no additional cost to you: Amazon





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. The grille was removed for testing.

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



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

Due to the sheer number of speakers I am testing at this time, all subjective and objective takeaways will be discussed in video form. 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.



Support the Cause

If you find this review helpful and want to help support the cause there are a few ways you can do so below. Your support helps me pay for new items to test, hardware, miscellaneous items needed for testing and costs of the site’s server space and bandwidth. Any help is very much appreciated.

Become a Patron!

Or using my Amazon affiliate link, if you are interested in purchasing anything from Amazon, which helps me gain a small commission at no additional cost to you.



You can also join my Facebook and YouTube pages if you’d like to follow along with updates.