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Monoprice Monolith K-BᾹS Bookshelf Speakers Listening Tests

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In my approximately 24’ by 13’ listening room, I set up the speakers with equal stand-off distances between the backwall and sidewall, and equal distance between speakers and listening position, with weeter at ear level and the speakers facing the listening position directly. A Pioneer SC-55 receiver was used in ‘Pure Direct’ mode, so no tonal processing would interfere with the speakers’ natural sound, and no subwoofers were there to disguise its low frequency abilities. Speaker distance from listening position is about 10 feet.

Music Listening

My first choice for evaluating speakers is content with a very cleanly-recorded vocal. Since human hearing is so acutely tuned to the sound of human voices, if anything is ‘off’ about a speaker, it will be heard here. The recording I used for this was Bjork’s 2001 album ‘Vespertine,’ which has a very clear and intimate recording of Bjork’s voice. Accompanying Bjork’s vocals is an elaborate and intricate arrangement of percussion, bells, and plucked string instruments such as the harp, celesta, and clavichord. The album mostly has an intimate and close sound, but at times it shifts to a large, almost operatic soundscape with sweeping strings and a choral accompaniment. Bjork’s voice was exquisitely rendered by the K-BᾹS speakers, and I can find no fault with them in that aspect. What I first noticed was the precise imaging. The soundstage as presented by the K-BᾹS speakers was quite vivid. The instruments had well-defined placement, as did Bjork, and the soundstage was broad and enveloping. Although the recording has a close and intimate sound, the K-BᾹS speakers transported the listener inside of that space instead of being placed at a distance. The high-pitched attacks of the bells and plucked were rendered with fine detail. The bass was very good for bookshelf speakers, but they do not have the punch of a good subwoofer, or at least the punch I am used to, since I have this nasty habit of running the subs really hot. 

Bjork-Vespertine.jpg     December.jpg

This piano recording just sounded right with the K-BᾹS speakers.

Another type of recording that is very good for assessing speakers is an instrumental solo. Here I turned to a long-popular album that I had only just discovered recently; George Winston’s ‘December’, released in 1982. ‘December’ is a superbly clean recording of some very skillfully played piano compositions with a seasonal flavor. The sound engineering and recording of the piano are first-rate, especially for a 35-year-old album. What many recordings of piano can miss are the high dynamics of the strike of the key, i.e. the attack of the sound envelope of each note. That attack has a power that a watered-down, compressed recording can turn into just some soft, mushy tinkling. ‘December’ has quiet piano passages, but also demonstrates the drama that the piano is capable of in other moments. The K-BᾹS speakers reproduced ‘December’ very well. As with ‘Vespertine’, the soundstage was well-defined. The piano sounded rich and clear. The strike was sharp when played as such, and the lingering decay of each note was not lost, even in notationally dense passages. This piano recording just sounded right with the K-BᾹS speakers, and I have nothing to complain about. Perhaps a larger and more powerful loudspeaker might bring out even more of the dynamics for those who like to listen at loud levels, but the K-BᾹS speakers executed the dynamics of ‘December’ well enough for me, and I did not listen to it at a soft volume.

Movie Listening

The timbre of each instrument was reproduced with veracity...

The first film I watched with the K-BᾹS speakers was ‘Fantasia 2000’, Disney’s long-awaited 1999 sequel to their ‘Fantasia’. I am betting readers already know about this film, so I won’t bother describing it again. The sound mix to ‘Fantasia 2000’ is, of course, almost entirely classical music (with a hint of jazz). The recording quality is outstanding, as one would expect from such a highly-anticipated feature, so therefore I used it to evaluate the K-BᾹS speaker’s sound on orchestral content. As with the other musical recordings, the K-BᾹS speakers produced a very convincing soundstage, with terrific imaging and great separation of instruments. The bombast and dynamics were there too, although the pounding of the bass drums certainly didn’t have the presence that a capable subwoofer or two would add. However, they reproduced the bass much better than one would have expected given their size. The timbre of each instrument was reproduced with veracity with many segments highlighting a particular instrument amidst the full orchestra. While the speaker pair was not able to match the enveloping sound of the full 7.1 soundtrack as replayed in a 7.1 system, they did provide an immersive experience thanks to their wide soundstage. ‘Fantasia 2000’, as heard on the Monoprice K-BᾹS speakers, was a delightful revisiting of this enchanting movie where great content and great playback equipment compliment each other.

everest.jpg     Fantasia2000c.jpg

District-9.jpgFor a more conventional film, I turned to ‘Everest’, the 2015 mountain-climbing drama based on true events. I had not previously seen ‘Everest’ but guessed that, given its production values and subject matter, it would contain a good sound mix to test a speaker’s capabilities. I was not wrong, since ‘Everest’ does indeed have a variety of scenes that would fall flat on an iffy speaker system. Scenes of avalanches and roaring snowstorms gave the low frequency capabilities of the K-BᾹS speakers a real workout, but it handled them much better than a typical bookshelf speaker. They did so well that at certain points I checked to make sure I had the subwoofers turned off. I am guessing there was very deep bass in the sound that it was missing, but I think that if I did not know what speaker was producing the sound, I would have thought a tower speaker was at work. The bass capabilities displayed by the K-BᾹS speakers in ‘Everest’ was most impressive for bookshelf speakers. Other sounds in the movie were presented nicely as well. Dialogue had no intelligibility issues, even with conversations carried out in the midst of a raging snowstorm. The music score, a mixture of traditional orchestral music with dashes of Tibetan music, was also given force by the K-BᾹS speakers. ‘Everest’ turned out to be a fine movie, and the K-BᾹS speakers were up to the task of recreating the intense conditions depicted in the film.

Another movie I watched with the K-BᾹS speakers was the 2009 science-fiction film ‘District 9’. I chose this film because of its very busy and dynamic sound mix that doesn’t shy away from bass. ‘District 9’ is rich with sound: science fiction sounds like alien speech and bizarre weapons, overlapping documentary production sounds, overlapping dialogue (sometimes with a multiplicity of languages), music scoring (both diegetic and non-diegetic), rapid editing between different situations, and gun battles with a variety of weapons and vehicles. A lesser speaker might turn this vibrant sound track into a cacophony of noise, but the K-BᾹS speakers managed to keep this complex soundscape coherent and lucid. As with ‘Everest’, I was surprised with the quantity and quality of bass these bookshelf speakers could produce. While a subwoofer would certainly made a contribution to the sound, the K-BᾹS speakers were still able to make ‘District 9’ watchable without one, certainly beyond what most bookshelf speakers in their price range and woofer size would have done.

 

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Recent Forum Posts:

Motrek posts on February 13, 2017 19:25
For $220 less, you can get a pair of Elac B6s which are super-well reviewed and have advertised bass extension down to 44Hz.

I'm actually in the market for something like this. I watch TV with a pair of Ascend CBM-170 SEs which have amazing midrange and treble output but are noticeably lacking in bass (58-20KHz +/- 3dB). It would be nice to buy some affordable speakers with more bass output but I'm not sure how to decide between, e.g., the Elacs and these Monoprice speakers…
shadyJ posts on February 06, 2017 22:36
Dennis Murphy, post: 1171434, member: 29480
Thanks again I still don't really understand why this curve is indicative of the weighting the ear would give, which intuitively and in my experience is dominated by the earlier arrival times. But I do see why it would be a useful means of determining whether an observed on-axis peak is benign or a serious resonance. However, i don't think it would take 70 measurements to establish that, and a waterfall plot should also give you that information.
Floyd Toole explains it with a bit more depth in his papers and lectures. For example, this one, from about the 20 min mark to about the 40 min mark he discusses these curves and how they affect room acoustics, etc. By the way, Floyd did mention to me that Sound Power is not the most useful curve in that bunch, so I wouldn't worry about it too much, but I do think it has some merit, so I include it in that graph.
Dennis Murphy posts on February 06, 2017 21:49
shadyJ, post: 1171379, member: 20472
Here is what Dr. Floyd Toole writes about Sound Power in his book:
“Sound power: is intended to represent all the sounds arriving at the listening position. It is the weighted average of all 70 measurements, with individual measurements weighted according to the portion of the spherical surface that they represent. Sound power is a measure of the total acoustical energy radiating through an imaginary spherical surface with the radius equal to the measurement distance. Thus, the on-axis curve has very low weighting because it is in the middle of other, closely adjacent measurement points (see the perspective sketch at the top of the figure), and measurements further off axis have higher weighting because of the larger surface area that is represented by each of those measurements. Ideally, such a measurement would be made at equally spaced points on the entire surface of the sphere, but this simplified spatial-sampling process turns out to be a very good approximation. The result could be expressed in acoustic watts, the true measure of sound power, but here it is left as a sound level, a frequency response curve having the same shape. This serves the present purposes more directly. Any bump that shows up in the other curves and persists through to this ultimate spatial average is a noteworthy resonance.”
Thanks again I still don't really understand why this curve is indicative of the weighting the ear would give, which intuitively and in my experience is dominated by the earlier arrival times. But I do see why it would be a useful means of determining whether an observed on-axis peak is benign or a serious resonance. However, i don't think it would take 70 measurements to establish that, and a waterfall plot should also give you that information.
shadyJ posts on February 06, 2017 17:13
Dennis Murphy, post: 1171371, member: 29480
Thanks. That does seem counter-intuitive in terms of the relative audible importance of on-axis vs extreme off-axis sound. I guess the technique is just supposed to tell us how relatively directional a speaker is?
Here is what Dr. Floyd Toole writes about Sound Power in his book:
“Sound power: is intended to represent all the sounds arriving at the listening position. It is the weighted average of all 70 measurements, with individual measurements weighted according to the portion of the spherical surface that they represent. Sound power is a measure of the total acoustical energy radiating through an imaginary spherical surface with the radius equal to the measurement distance. Thus, the on-axis curve has very low weighting because it is in the middle of other, closely adjacent measurement points (see the perspective sketch at the top of the figure), and measurements further off axis have higher weighting because of the larger surface area that is represented by each of those measurements. Ideally, such a measurement would be made at equally spaced points on the entire surface of the sphere, but this simplified spatial-sampling process turns out to be a very good approximation. The result could be expressed in acoustic watts, the true measure of sound power, but here it is left as a sound level, a frequency response curve having the same shape. This serves the present purposes more directly. Any bump that shows up in the other curves and persists through to this ultimate spatial average is a noteworthy resonance.”
Dennis Murphy posts on February 06, 2017 16:51
shadyJ, post: 1171350, member: 20472
You can get the standard online, but its a tad pricey, something like $120 last time I looked.

The weighting numbers makes the direct axis angle very small and insignificant compared to the angles at and around 90 degrees. This is because the surface area of the sphere that the direct axis and near direct axis represents is very small. The weighting gives more weight to angles as they approach 90 degrees, with 90 degrees being given the most weight.

Thanks. That does seem counter-intuitive in terms of the relative audible importance of on-axis vs extreme off-axis sound. I guess the technique is just supposed to tell us how relatively directional a speaker is?
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