This is a review and detailed measurements of the Polk Signature Elite ES20 bookshelf speaker. I purchased it from Amazon for US $349 a pair including shipping.
I really like the look and finish of this series from Polk. Despite budget pricing, it looks nice and purposeful as you can tell from the unique rear port plate:
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.
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. No grill was used. Measurement temperature was about 62 degrees F (17 degrees C).
Polk ES20 Measurements
Let's start with our usual "spinorama" graph:
On axis is reasonably good, marred by some resonances between 600 and 1000 Hz. And some unevenness in high treble area. There is a directivity dip around 4 kHz.
I forgot to note on the graph the deep bass extension. F10 is at nearly 35 Hz! This is partly due to a cabinet that is deeper than normal.
We see the cause of that roughness around 600 Hz in our near-field measurements:
We see more of a dip in directivity caused in vertical axis mostly:
Fortunately my listening room has a thick carpet and high ceilings so I will be hearing a more optimal off-axis response than averaged above.
Predicted in-room response with my custom trend line is thus:
I usually draw the trend line after my listening tests are completed and do in a manner that is consistent with that experience. See the next section.
I was impressed by the smooth and constant horizontal beam width and dispersion:
This also has wider than usual response which should create a more diffused field around the speaker (my preference).
Vertically we have the usual restrictions but again, the sweet spot is larger than I normally see in this class:
I like the low distortion especially at 86 dBSPL:
But notice how that resonance around 600 Hz is also showing up here in the form of distortion. This means that we will have impact beyond that frequency due to harmonics.
We see the same resonance in impedance graph and waterfall:
Finally for fans of timing tests, here are the impulse and step response:
Polk ES20 Listening Tests
My female starting track which lacks bass sounding a bit muddy/tubby and somewhat bright. So I brought out the EQ tool:
First filter was around 600 Hz. It is a small filter but per past experience, it not only removed a bit of muddiness but also reduced distortion. The latter caused the sound to be more open and clear. Once there, on tracks with good bass, the sound was more or less balanced. But with female tracks without such, it sounded too bright to me. A quick and dirty shelving filter fixed that nicely.
Once there, I was extremely impressed with the fidelity. Track after track sounded beautiful. Not only was the tonality right but there was this clarity and lack of distortion that kept impressing me. ES20 could play pretty loud and distorted gracefully in that the woofer just lost deep bass and became a tubby. Pull back a bit and you were golden.
Conclusions
I can see Polk having to both want to create an accurate speaker while working within strict budget and retain channel that demands "showroom sound." To that end, they have done a very good job here, producing bass response that is way above what you expect. And do so with very little distortion. The only issue is the port/cabinet resonance which makes the sound muddy and screws up upper bass a bit. And elevated treble which can be a bit much if bass response is not there. Fortunately both of these factors are excess output meaning EQ not only fixes them, but also reduces distortion. Result is a speaker and sound that you can really be proud of.
I can recommend the Polk Signature Elite ES20 as is but hugely so with equalization. You are getting so much performance for so little money.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I really like the look and finish of this series from Polk. Despite budget pricing, it looks nice and purposeful as you can tell from the unique rear port plate:
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.
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. No grill was used. Measurement temperature was about 62 degrees F (17 degrees C).
Polk ES20 Measurements
Let's start with our usual "spinorama" graph:
On axis is reasonably good, marred by some resonances between 600 and 1000 Hz. And some unevenness in high treble area. There is a directivity dip around 4 kHz.
I forgot to note on the graph the deep bass extension. F10 is at nearly 35 Hz! This is partly due to a cabinet that is deeper than normal.
We see the cause of that roughness around 600 Hz in our near-field measurements:
We see more of a dip in directivity caused in vertical axis mostly:
Fortunately my listening room has a thick carpet and high ceilings so I will be hearing a more optimal off-axis response than averaged above.
Predicted in-room response with my custom trend line is thus:
I usually draw the trend line after my listening tests are completed and do in a manner that is consistent with that experience. See the next section.
I was impressed by the smooth and constant horizontal beam width and dispersion:
This also has wider than usual response which should create a more diffused field around the speaker (my preference).
Vertically we have the usual restrictions but again, the sweet spot is larger than I normally see in this class:
I like the low distortion especially at 86 dBSPL:
But notice how that resonance around 600 Hz is also showing up here in the form of distortion. This means that we will have impact beyond that frequency due to harmonics.
We see the same resonance in impedance graph and waterfall:
Finally for fans of timing tests, here are the impulse and step response:
Polk ES20 Listening Tests
My female starting track which lacks bass sounding a bit muddy/tubby and somewhat bright. So I brought out the EQ tool:
First filter was around 600 Hz. It is a small filter but per past experience, it not only removed a bit of muddiness but also reduced distortion. The latter caused the sound to be more open and clear. Once there, on tracks with good bass, the sound was more or less balanced. But with female tracks without such, it sounded too bright to me. A quick and dirty shelving filter fixed that nicely.
Once there, I was extremely impressed with the fidelity. Track after track sounded beautiful. Not only was the tonality right but there was this clarity and lack of distortion that kept impressing me. ES20 could play pretty loud and distorted gracefully in that the woofer just lost deep bass and became a tubby. Pull back a bit and you were golden.
Conclusions
I can see Polk having to both want to create an accurate speaker while working within strict budget and retain channel that demands "showroom sound." To that end, they have done a very good job here, producing bass response that is way above what you expect. And do so with very little distortion. The only issue is the port/cabinet resonance which makes the sound muddy and screws up upper bass a bit. And elevated treble which can be a bit much if bass response is not there. Fortunately both of these factors are excess output meaning EQ not only fixes them, but also reduces distortion. Result is a speaker and sound that you can really be proud of.
I can recommend the Polk Signature Elite ES20 as is but hugely so with equalization. You are getting so much performance for so little money.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
.
