Foreword / YouTube Video Review
One of these speakers was dropshipped to me by a viewer and I purchased another to round out the set. 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. 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.
- Rockville RockTower 68B Black Grain Home Audio tower Speaker
- RMS Power: 125 Watts
- Peak Power: 500 Watts
- Woofer: 6.5” x 2
- Midrange: 6.5” x 1
- Tweeter: 1” Silk dome tweeter
- Each Woofer has a 15 oz magnet and 1.25” voice coil
- Midrange has 8 oz magnet and 1” voice coil
- Cabinet material: Top quality MDF with beautiful vinyl wood grain finish
- Silk dome tweeter gives crisp and realistic sounding highs (silk dome are generally more musical)
- Detachable grill (speaker looks amazing with and without the grill)
- Vented enclosure gives a boost of punchy bass at low frequencies
- Gold-plated 5-way binding post terminals can accept banana, bare wire, spade terminals, and more
- Impedance: 8 ohm
- Color: Black Grain (also available in white grain and classic wood grain)
- Ultra-stiff Polypropylene dust cap on woofer
- Built-in 3-way crossover separates frequencies so each driver can work together
- Rubber surrounds on woofer
- Frequency Response: 30Hz-20KHz
- Sensitivity:87 dB 1W/1m
- High Quality Golden Terminals
- Dimensions of each speaker (inches): 10.43” x 7.87” x 41.73”
- One pc speakers Shipping carton dimensions (inches): 14.211.446.5inch
- Weight per speaker: 26.2 lb
As of this writing MSRP is $218 USD for the 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 tweeter. Speaker was broken in. No grille was 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):
Additional Measurements
Impedance
Response Linearity
Horizontal Frequency Response:
Vertical Frequency Response:
Step Response
Group Delay
Burst Decay
This data is full anechoic where most spectral decay type graphics are created using quasi-anechoic data. For more information on the differences between Burst Decay and Cumulative Spectral Decay (CSD) graphics please see Section 6.5 of the ARTA User Manual linked below. I would like to extend a professional "thank you" to Ivo Mateljan for this software.
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 Listening Impressions
There’s no getting around it: this is a very bad speaker. I understand the first thought might be, “What did you expect for only $100?” Sure, that’s fair. I think, however, the better question is, “Why would you bother making a product that is so handicapped by performance and price?”
This speaker sounds bad. From bass to treble. It’s a mess.
Most speakers have a tradeoff or two (or more, when budget-oriented) that we can understand and look past. This speaker has too many to ignore. The bass is boomy and resonant. To some, this may translate as “punch” or “fast,” but that’s because there’s no real bass extension to speak of—this is essentially a one-note wonder in the midbass. Then there’s the strong resonance around 200 Hz that creates a sharp dip and hollow midrange—especially for male vocals. From here up to about 800 Hz, the speaker may be manageable. But going into the upper midrange and treble, you hear many resonances and experience an extremely uneven response.
Quite frankly, it’s actually confusing to listen to anything through these speakers because the sound is so altered by the speaker itself that it doesn’t make sense. It even caused me to question whether I had some DSP settings enabled during my listening tests (which are always done before I measure the speakers). The upper midrange is missing bite, attack, and clarity. The treble is way too bright to ignore (technically, it’s 4–6 dB over the midrange).
Then there’s the effect of the off-axis response—which can arguably be more important to the overall sound, especially in smaller rooms where there are more reflections from this off-axis sound. It’s so bad that I’m not really sure where to start. So, I think I’ll just leave it at that.
Burst decay shows significant ringing at multiple frequencies: 250 Hz, 800 Hz, 1.5 kHz, and 4–6 kHz.
Distortion and compression are quite bad as well. There’s no separation between orders of distortion. Usually, you’d at least see 4th and 5th-order harmonics with some clear separation from 2nd and 3rd. Not here. Instantaneous compression shows significant issues in multiple areas—most notably, a large amount of “enhancement” (louder sound due to higher distortion) in the lower treble region around 4–5 kHz. That’s likely a sign the tweeter is being pushed too low. With long-term compression, we see similar patterns as well.
Long story short: it’s novel to have a tower speaker for $109 each. But once you hear it, the novelty wears off quickly. And when you see the data, your suspicions about the price-vs-performance tradeoff are confirmed. If you’re looking for sound quality on a budget then I encourage you to spend an extra $30 and buy something like the Polk XT20 bookshelf speakers ($250/pair) or even the cheap Sony Bookshelf SS-CS5M2 speakers ($169/pair) with a small subwoofer. If you want something that just makes sound, check your local Facebook Marketplace listings for $50 speakers and call it a day.
- Erin
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