In this review, we will be comparing RTi A1 and Q150, two Passive Bookshelf speakers from Polk Audio and KEF. Let's have a brief look at the main features
of Polk RTi A1 and KEF Q150 first before getting into our more
detailed comparison.
Polk RTi A1 Key Specs
- 2-way Design
- 1" Dome Tweeter
- 5.25" Polymer composite Woofer
- 60-26k Hz Frequency Response
- 89 dB Sensitivity
- Impedance: 8ohms
- Power Range:20-125watts
- Weight:5.44kg
- Dimensions (H x W x D): 304.8" x 7.3" x 11.5"( 304.8 x 187.5 x 292.1mm )
KEF Q150 Key Specs
- 2-way Design
- 11th Generation Uni-Q Driver
- 1" Dome Tweeter
- 5.25" Aluminum Woofer
- 51-28k Hz Frequency Response
- 86 dB Sensitivity
- Impedance: 8ohms
- Power Range:10-100watts
- Weight:5.60kg
- Dimensions (H x W x D): 303.0" x 7.0" x 10.9"( 303.0 x 180.0 x 278.0mm )
What size room are the Polk RTi A1 and KEF Q150 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision factor. Here we have compared their suitability to various sizes of environments considering their size and max power parameters:
| Listening Environment* |
Polk RTi A1 |
KEF Q150 |
| Near-field |
Poor |
Average |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| Very Large Room |
Poor |
Bad |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2, Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: > 400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual listening experience changes depending on floor height, room shape, surface materials, listening position, speaker locations, etc.)
In the following sections, we will get into more detail in order to better understand how the Polk RTi A1 and KEF Q150 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both RTi A1 and Q150 are 2-way speakers.
| Driver |
Polk RTi A1 |
KEF Q150 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
RTi A1 features a 1" silk polymer composite Dome Tweeter and 1 x 5.25" Polymer composite Woofer with a Crossover frequency at 1900Hz. On the other hand, the Q150 features a 1" vented aluminum Dome Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
RTi A1 has a frequency range of 60-26k Hz whereas Q150 has a frequency range of 51-28k Hz. With a minimum frequency of 51Hz, the Q150 can go significantly deeper on the low side and provide stronger bass compared to the RTi A1's min frequency of 60Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
RTi A1 and Q150 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. RTi A1 sensitivity is rated at 89 dB and the Q150's is at 86 dB. This 3 dB difference makes the Polk RTi A1 a more sensitive speaker compared to KEF Q150, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.
RTi A1 can handle a max power of 125 watts RMS from the amp the whereas Q150 has a max power handling value of 100 watts RMS, 25 watts less than the RTi A1.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
RTi A1 features Pair of Dual 5-way Binding Posts - Gold-Plated posts which make bi-amping or bi-wiring possible. Q150 has a Post which doesn't feature bi-amping/bi-wiring.
KEF Q150's Post terminals
Cabinet Type and Port Position
RTi A1 has a back and front firing port whereas Q150 has a rear firing ports.
KEF Q150 Port
Physical Specs
Size of a speaker can sometimes become an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Polk RTi A1's and KEF Q150's external dimensions. Polk RTi A1 has external dimensions of 304.8 x 187.5 x 292.1mm ( 12.0 x 7.3 x 11.5inch) whereas KEF Q150 has external dimensions of 303.0 x 180.0 x 278.0mm ( 11.9 x 7.0 x 10.9inch) .
Polk RTi A1 is clearly the larger of the two speakers. Its body is 7.5mm wider, 1.8mm taller and 14.1mm deeper than KEF Q150.
Below you can see the front view size comparison of Polk RTi A1 and KEF Q150 in scale.
Comparison image of Polk RTi A1 and KEF Q150 Size and External Dimensions
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the Polk RTi A1 is approximately 547.7cm2 / 84.9inch2 and base area of the KEF Q150 is approximately 500.4cm2 / 77.6inch2. The RTi A1 requires 9% more surface area than the Q150 which gives it a small disadvantage on placement in tight spaces.
Here is an another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of Polk RTi A1 and KEF Q150 on a Media Console
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The Polk RTi A1 weighs 5.44kg / 12lbs and the KEF Q150 weighs 5.60kg / 12.3lbs. This makes the Q150 3% heavier than the RTi A1.
Here is a comparison of how RTi A1 and Q150's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Polk RTi A1?
Here are the items that are included inside the box of RTi A1:
2 Cherry bookshelf speakers 2 Self-tapping screws 8 Self-adhesive rubber feet Owner's Manual Template Online registration sheet Polk Audio product brochure
What's in the Box of KEF Q150?
Here are the items that come with the Q150:
2 Bookshelf loudspeakers 2 Foam port plugs 8 Self-adhesive rubber feet Owner's Manual Warranty Registration Card