This is a review and detailed measurements of the Polk Monitor 40 Series II bookshelf "MTM" speaker. It is on kind loan from a member and costs US $200 on Amazon for a pair including Prime shipping.
The Monitor 40 looks pretty decent for such a budget speaker:
After decades of surviving in brutal consumer market for speakers, Polk knows what it is doing here. And that involves super lightweight design and shoddy construction that allowed the front baffle completely separate itself from the enclosure in shipping!
They have a rabbet all around which provides for large surface area for the glue and air tight construction. Why did they resort to these wedges that gave out due to weak fibers in the MDF? A couple of screws would have helped keep it there as well.
At least there is some foam inside:
They put money toward bi-wiring terminals that no one uses but likely checks a box for marketing:
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
I performed over 1000 measurement which resulted in error rate of less than 1% or so.
Temperature was 68 degrees F.
Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.
Reference axis was the tweeter center.
Polk Monitor 40 Series II Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
Lots of issues here starting with tweeter frequency not being flat and elevated. The woofers are getting more directional before tweeter takes over and presents a wider dispersion. Near-field measurement shows the many flaws:
We clearly see the issues with the tweeter but also the port letting out a resonance right at the crossover. The woofers are allowed to play up to 5 kHz making me wonder if the filter for it has too little slope.
Early window response has no choice but to be messy:
Summing these produces an estimated response in your room that is likely to be quite bright:
Bass response is low which helps keep distortion in check especially given the dual woofers:
Horizontal beam width is not pretty as we could already guess from the spin graph:
I think this is the first MTM configuration speaker we have tested so its classic dispersion is nice to see:
Edit: forgot the impedance and phase:
Polk Monitor 40 Series II Listening Tests
Oh wow, this speaker is bright! High frequency notes literally jump out of the speaker and meet you half way! I must say, I can see the appeal of that in a showroom and with casual listeners. Bad choice to throw at me though as I am super sensitive to high frequency accentuation (spent so much time training to hear distortion in them). So I had to pull out the parametric EQ tool in Roon right away:
This is a quick and dirty correction to make the sound bearable. It was still bright but likely if you add a sub, it would balance it out.
Power handling was excellent because there is essentially no sub-bass reproduction so my killer tracks of this kind did not do much to Monitor 40.
Conclusions
The Polk Monitor 40 Series II is a great example of what you have to do to bring the cost down to crazy low yet keep the showroom appeal high. is this the most broken thing Polk could design? No, that would require a lot of distortion as well which I did not find. Still, without equalization and lots of playing around with that I don't see this being a useful speaker to live with, monetary savings be damned. Eat less outdoors, save the money, and buy something better please!
I can not recommend the Polk Monitor 40 Series II.
------------
As always, questions, comments, recommendations, etc. are welcome.
Had a miserable day yesterday. Why is it that all plumbing work is hell? We spent a fortune to have a yard guy dig trenches in our orchard for sprinklers. We were not here to watch the guy and he used the thinnest PVC tubes he could to save money -- much like Polk above. Worse yet, didn't know much about plumbing and created many sources of water leaks. This is the second time I have had to dig a ditch 3 feet down in thick mud and clay.
I could barely expose the failure point and have to dig more to make space to fix it. So more muddy miserable days are awaiting me until I get this thing fixed....
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The Monitor 40 looks pretty decent for such a budget speaker:
After decades of surviving in brutal consumer market for speakers, Polk knows what it is doing here. And that involves super lightweight design and shoddy construction that allowed the front baffle completely separate itself from the enclosure in shipping!
They have a rabbet all around which provides for large surface area for the glue and air tight construction. Why did they resort to these wedges that gave out due to weak fibers in the MDF? A couple of screws would have helped keep it there as well.
At least there is some foam inside:
They put money toward bi-wiring terminals that no one uses but likely checks a box for marketing:
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
I performed over 1000 measurement which resulted in error rate of less than 1% or so.
Temperature was 68 degrees F.
Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.
Reference axis was the tweeter center.
Polk Monitor 40 Series II Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
Lots of issues here starting with tweeter frequency not being flat and elevated. The woofers are getting more directional before tweeter takes over and presents a wider dispersion. Near-field measurement shows the many flaws:
We clearly see the issues with the tweeter but also the port letting out a resonance right at the crossover. The woofers are allowed to play up to 5 kHz making me wonder if the filter for it has too little slope.
Early window response has no choice but to be messy:
Summing these produces an estimated response in your room that is likely to be quite bright:
Bass response is low which helps keep distortion in check especially given the dual woofers:
Horizontal beam width is not pretty as we could already guess from the spin graph:
I think this is the first MTM configuration speaker we have tested so its classic dispersion is nice to see:
Edit: forgot the impedance and phase:
Polk Monitor 40 Series II Listening Tests
Oh wow, this speaker is bright! High frequency notes literally jump out of the speaker and meet you half way! I must say, I can see the appeal of that in a showroom and with casual listeners. Bad choice to throw at me though as I am super sensitive to high frequency accentuation (spent so much time training to hear distortion in them). So I had to pull out the parametric EQ tool in Roon right away:
This is a quick and dirty correction to make the sound bearable. It was still bright but likely if you add a sub, it would balance it out.
Power handling was excellent because there is essentially no sub-bass reproduction so my killer tracks of this kind did not do much to Monitor 40.
Conclusions
The Polk Monitor 40 Series II is a great example of what you have to do to bring the cost down to crazy low yet keep the showroom appeal high. is this the most broken thing Polk could design? No, that would require a lot of distortion as well which I did not find. Still, without equalization and lots of playing around with that I don't see this being a useful speaker to live with, monetary savings be damned. Eat less outdoors, save the money, and buy something better please!
I can not recommend the Polk Monitor 40 Series II.
------------
As always, questions, comments, recommendations, etc. are welcome.
Had a miserable day yesterday. Why is it that all plumbing work is hell? We spent a fortune to have a yard guy dig trenches in our orchard for sprinklers. We were not here to watch the guy and he used the thinnest PVC tubes he could to save money -- much like Polk above. Worse yet, didn't know much about plumbing and created many sources of water leaks. This is the second time I have had to dig a ditch 3 feet down in thick mud and clay.
I could barely expose the failure point and have to dig more to make space to fix it. So more muddy miserable days are awaiting me until I get this thing fixed....Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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