This is a review and detailed measurements of the Polk Atrium 4 speaker. It was kindly sent to me by a member and costs US $177 from Amazon including Prime shipping.
As the saying goes, you have seen one outdoor speaker, you have seen them all:
I don't know if the owner had it outside or not but there are a few specs that seem to have lost their color or started to rust.
Binding posts point down so take that into account when deciding where to mount them relative to your wires:
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 500 measurement which resulted in error rate of around 2%.
Testing temperature was around 58 degrees F but speaker however was kept warm indoors prior to measurements.
Reference axis was that of the tweeter.
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.
Polk Atrium 4 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:
The elevated highs stand out as does sudden directivity error around 4 kHz. Polk specs this as 89 dB. That is only true of the peak output of the tweeter. Bass response at best is 85 dB dropping to 82 dB so quite insensitive. We see the response variation in near-field measurement of each driver:
Perhaps they are counting on back wall enhancement of the bass region.
Our early window and predicted in-room response don't quite apply to a speaker mounted to a wall outdoor but here they are anyway:
Beamwidth is uneven:
It is not too bad up to 10 kHz though so maybe in practice, it would be better than it seems.
Vertical directivity is typical:
Impedance is low:
I was surprised at low level of distortion at 86 dBSPL:
Polk Atrium 4 Listening Tests
I first had them on a stand away from walls, i.e. same place I test all speakers. The sound was almost all tweeter. So I placed it in front of my LCD TV and that brought in much needed bass response. On some tracks it was a bit boomy but otherwise, what you heard was exaggerated highs but pretty clean. I think this is due to the exaggeration being at the top of the frequency range and distortion being low. Try as I did, I could not hate the sound.
A lot of power was required to get good volume. Good news was that the sound was clean with no break up when I was pushing it. Sub-bass did not impact the speaker due to its sealed design.
Conclusions
Clearly this is an imperfect design both objective and subjectively. It might however work better in its intended application of being mounted on a wall and not listened to necessarily on-axis. It definitely sounds better than a driver in cheap plastic box.
I can't bring myself to put the Polk Atrium 4 on my recommended list but per above, I could not hate it either.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
As the saying goes, you have seen one outdoor speaker, you have seen them all:
I don't know if the owner had it outside or not but there are a few specs that seem to have lost their color or started to rust.
Binding posts point down so take that into account when deciding where to mount them relative to your wires:
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 500 measurement which resulted in error rate of around 2%.
Testing temperature was around 58 degrees F but speaker however was kept warm indoors prior to measurements.
Reference axis was that of the tweeter.
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.
Polk Atrium 4 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:
The elevated highs stand out as does sudden directivity error around 4 kHz. Polk specs this as 89 dB. That is only true of the peak output of the tweeter. Bass response at best is 85 dB dropping to 82 dB so quite insensitive. We see the response variation in near-field measurement of each driver:
Perhaps they are counting on back wall enhancement of the bass region.
Our early window and predicted in-room response don't quite apply to a speaker mounted to a wall outdoor but here they are anyway:
Beamwidth is uneven:
It is not too bad up to 10 kHz though so maybe in practice, it would be better than it seems.
Vertical directivity is typical:
Impedance is low:
I was surprised at low level of distortion at 86 dBSPL:
Polk Atrium 4 Listening Tests
I first had them on a stand away from walls, i.e. same place I test all speakers. The sound was almost all tweeter. So I placed it in front of my LCD TV and that brought in much needed bass response. On some tracks it was a bit boomy but otherwise, what you heard was exaggerated highs but pretty clean. I think this is due to the exaggeration being at the top of the frequency range and distortion being low. Try as I did, I could not hate the sound.
A lot of power was required to get good volume. Good news was that the sound was clean with no break up when I was pushing it. Sub-bass did not impact the speaker due to its sealed design.
Conclusions
Clearly this is an imperfect design both objective and subjectively. It might however work better in its intended application of being mounted on a wall and not listened to necessarily on-axis. It definitely sounds better than a driver in cheap plastic box.
I can't bring myself to put the Polk Atrium 4 on my recommended list but per above, I could not hate it either.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
