Monoprice Monolith K-BᾹS Bookshelf Speakers Review

gene

gene

Audioholics Master Chief
Administrator
The new Monolith K-BAS bookshelf speakers from Monoprice achieve a rare feat for their price and size: true sub 50 Hz bass extension. That is no small task for a medium-sized, $500/pr bookshelf speaker using only a 5.25" woofer. Monoprice has thrown their hat into the hi-fi speaker market, but does their K-BAS speaker do more than just excellent bass extension or does the good news stop there?

Read our review of the K-BAS speakers to find out!



Read: Monoprice Monolith K-BᾹS Bookshelf Speakers Review
 
R

RTPBob

Enthusiast
Nice review. I owned one of the first set of tower speakers to use Phil Clements' bass enhancing technology when he first started his own company. Enjoyed them and talking with Phil for many years.

Bob
 
BoredSysAdmin

BoredSysAdmin

Audioholic Slumlord
@shadyJ Great review as usual. Curious on MP's K-bas vs Dennis's AAs - yes - later lack some of low end bass, but otherwise they measurements is noticeably flatter afaik
 
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shadyJ

Speaker of the House
Staff member
Thank you Bored. Comparing the K-BAS graphs to the Philharmonic AA graph could potentially be misleading. The reason is I am using a larger Y / X scale, and this will exaggerate ripples more on my graph, so my graph is a bit more unforgiving. You have to keep scale in mind when comparing the two. Also I am using minor grid lines in my graph and Dennis is not, and that may seem to accentuate non-linearities in my graph when comparing the two.
 
BoredSysAdmin

BoredSysAdmin

Audioholic Slumlord
The reason is I am using a larger Y / X scale, and this will exaggerate ripples more on my graph, so my graph is a bit more unforgiving.
100% agree, only to the opposite of what you're saying. You've used more forgiving 50db scale while Dennis posted much less forgiving 35db scale
Now, there could be some smoothing going on, but by the looks of both plots neither are heavy handed.
 
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shadyJ

Speaker of the House
Staff member
I don't mean to say scale by dB, I mean scale by ratio of graph dimensions. Dennis is using what looks to be close to a 2 to 1 ratio of x vs y, whereas mine is not quite 1.5 to 1, so the Y scale is much more stretched out. This will magnify any ripples or ruggedness.

Also, it looks to me like Dennis has 45 dB represented on the Y axis, not 35 dB, so his dB scale should be pretty close to mine
 
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BoredSysAdmin

BoredSysAdmin

Audioholic Slumlord
I don't mean to say scale by dB, I mean scale by ratio of graph dimensions. Dennis is using what looks to be close to a 2 to 1 ratio of x vs y, whereas mine is not quite 1.5 to 1, so the Y scale is much more stretched out. This will magnify any ripples or ruggedness.

Also, it looks to me like Dennis has 45 dB represented on the Y axis, not 35 dB, so his dB scale should be pretty close to mine
Ahh, Image scale. Gottacha. Here's both graphs merged to same (or very similar) scale to the best of my very humble gimp skills.
 
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D

Dennis Murphy

Audioholic General
Ahh, Image scale. Gottacha. Here's both graphs merged to same (or very similar) scale to the best of my very humble gimp skills.
Thanks for going to the trouble to construct that comparison. All I would add is that my graph is completely unsmoothed. That's why you see so many minor jagged deviations that would disappear with the degree of smoothing used on the Audiophile measurement.
 
KEW

KEW

Audioholic Overlord
@shadyJ, I really like the way you presented the graphs - especially the two angles of the horizontal off-axis response. I wish more people did this! And nice write up too - thanks for thinking out loud over the measurements!
Thanks!
 
KEW

KEW

Audioholic Overlord
Interesting option at $600 (amp is $200 separately):
https://www.monoprice.com/Product?p_id=18833




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Because of its lossy nature, digital music can often lose some of the depth and warmth that gives it life. Wireless streaming adds an additional layer of digital compression, which can further degrade the audio quality. The addition of the tube preamplifier stage adds back some of the warmth and richness, breathing new life into your digital music, while the Qualcomm® aptX™ audio codec ensures clean and clear Bluetooth® streaming.
 
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shadyJ

Speaker of the House
Staff member
@shadyJ, I really like the way you presented the graphs - especially the two angles of the horizontal off-axis response. I wish more people did this! And nice write up too - thanks for thinking out loud over the measurements!
Thanks!
Thanks. One thing I am proud of about this review is- to my knowledge- it is the first time the full suite of graphs used by Harman and CEA-2034 style presentation has been done for any speaker review. This involves taking 70 sweeps, or a sweep for every 10 degrees all around the speaker on both the horizontal and vertical axis, and then processing them to achieve those curves.
 
KenM10759

KenM10759

Audioholic Samurai
That's a LOT of work! Thankfully you get generously rewarded for the effort....in accolades. I'd guess you won't be getting the vacation home on that pay scale for such effort. ;)

But it's definitely appreciated and good of you to point out the "painstaking measures" undergone to get these results. Thank you.
 
slipperybidness

slipperybidness

Audioholic Warlord
I'm really curious if MP manufactures these, or if there is some OEM involved.
 
KenM10759

KenM10759

Audioholic Samurai
I sincerely doubt Monoprice has any manufacturing of their own. They are a distribution company and would contract a Chinese or other offshore OEM plant to make things like that. The question would better be does Monoprice have any resident engineers to design things like this and create specifications for their contractors to meet?
 
slipperybidness

slipperybidness

Audioholic Warlord
I sincerely doubt Monoprice has any manufacturing of their own. They are a distribution company and would contract a Chinese or other offshore OEM plant to make things like that. The question would better be does Monoprice have any resident engineers to design things like this and create specifications for their contractors to meet?
Agreed, then of course, that begs the question, "who is the OEM?".
 
D

Dennis Murphy

Audioholic General
Thanks. One thing I am proud of about this review is- to my knowledge- it is the first time the full suite of graphs used by Harman and CEA-2034 style presentation has been done for any speaker review. This involves taking 70 sweeps, or a sweep for every 10 degrees all around the speaker on both the horizontal and vertical axis, and then processing them to achieve those curves.
I also appreciate all of the thought and effort that went into the measurements. However, I'm still a little puzzled by the "Total Sound Power" plot. Is that the one achieved by taking the 70 vertical and horizontal polar plots? If so, is the resulting composite just the unweighted average of all the plots? Or is there some algorithm applied that takes into account what is believed to be the relative importance of each plot? If it's the former, I'm not sure what we end up with, since the ear certainly doesn't process all of these off-axis measurements equally.
 
KenM10759

KenM10759

Audioholic Samurai
In most cases an Original Equipment Manufacturer is kept confidential as part of the agreement because the contract can change and go to a lower bidder. There are some companies (such as the one I work for) who own their own factories in China and while they don't "own" the workforce they do have their own staffing for management and quality control. Other larger distributors like Monprice who do a LOT of business with one factory may have one or more paid representatives in that factory to oversee operations of their own products from a quality standpoint, while the factory may indeed be making products for other customers including competitors.
 
S

shadyJ

Speaker of the House
Staff member
I also appreciate all of the thought and effort that went into the measurements. However, I'm still a little puzzled by the "Total Sound Power" plot. Is that the one achieved by taking the 70 vertical and horizontal polar plots? If so, is the resulting composite just the unweighted average of all the plots? Or is there some algorithm applied that takes into account what is believed to be the relative importance of each plot? If it's the former, I'm not sure what we end up with, since the ear certainly doesn't process all of these off-axis measurements equally.
Hello Dennis,

From the CEA-2034 standard:
"Sound Power
The sound power is the weighted rms average of all 70 measurements, with individual measurements weighted according to the portion of the spherical surface that they represent. Calculation of the sound power curve begins with a conversion of SPL to pressure, a scalar magnitude. The individual measures of sound pressure are then weighted according to the values shown in Appendix C and an energy average (rms) is calculated using the weighted values. The final average is converted to SPL.

Sound Power Directivity Index (SPDI)
The the purposes of this standard the Sound Power Directivity Index is defined as the difference between the listening window curve and the sound power curve. An SPDI of 0 indicated omnidirectional radiation. The larger the SPDI, the more directional the loudspeaker is in the direction of the reference axis."
 
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shadyJ

Speaker of the House
Staff member
I sincerely doubt Monoprice has any manufacturing of their own. They are a distribution company and would contract a Chinese or other offshore OEM plant to make things like that. The question would better be does Monoprice have any resident engineers to design things like this and create specifications for their contractors to meet?
It looks like Monoprice uses this design but they do make some changes to it and put their stamp on it.
 
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