Polk Audio f/x 500i Bipole/Dipole Surrounds — Made in USA, Pair

Polk Audio f/x 500i — 19.4 lb Mirror-Imaged Surrounds, Switchable Bipole or Dipole, Made in the USA

A matched left/right pair of Polk Audio f/x 500i surround speakers, built in the United States, and a good deal more speaker than the surrounds most people end up with.

Why the Weight Matters

Weight tells the story before anything else does. These are 19.4 lbs each — half again as heavy as Polk’s own FXi A6 that followed them, and more than double the FXi A4, in a cabinet that is slightly smaller than the A6’s. That is not incidental. A surround speaker is usually where a manufacturer economises, because it is the one nobody auditions; a 19 lb cabinet is what it looks like when they did not.

The Driver Arrays

Inside each is a two-array design on a triangular cabinet. One angled face carries a 1 inch tri-laminate dome tweeter alongside a 6.5 inch blue composite Dynamic Balance woofer and the port. The opposite face carries a second matching tweeter, and the two arrays sit 45 degrees apart so the speaker throws a deliberate mix of direct and reflected sound rather than pointing everything at one seat. The tri-laminate domes are built from vapour-deposited micro-layers of stainless steel and aluminium — the tweeter Polk reserved for its upper models in this era, and a different material from the silk domes used in the FXi range that replaced these.

Bipole or Dipole

The rear-panel switch flips between bipole and dipole, and it is what makes the pair work in any room rather than one. Bipole runs the two arrays in phase and gives distinct, locatable effects, which is what you want on the wall behind the listening position. Dipole runs them out of phase and produces a diffuse, enveloping field with no obvious source, which is what you want on the side walls. Most surrounds force the room to suit the speaker. These adapt to the room you have, and you can change your mind later without changing speakers.

Mounting and Connections

Two details on the back that will matter more than they sound. The wall mounts are keyhole slots cut into the cabinet itself, so there is no bracket to source, match or lose — the speaker goes straight onto a screw in the wall. And Polk fitted heavy-duty moulded rubber standoffs around them, which do two jobs at once: they hold the cabinet off the wall surface so it is mechanically isolated rather than buzzing against drywall, and the gap they create is exactly where the speaker cable runs. Anyone who has hung a speaker and then discovered the cable will not sit flat behind it will recognise the problem being solved. It is the sort of thing that only gets designed by someone who has actually installed one.

Driving Them

At 90 dB sensitivity into 8 ohms these are also easier to drive than either FXi model that succeeded them, both of which are 88 dB. That gap is small on paper and matters more than it looks, because surround channels are where a receiver’s amplifier section is thinnest — the front three get the attention and the rear pair gets what is left. Two decibels of efficiency is the difference between surrounds that keep up during a loud scene and surrounds that quietly fall behind it. They handle up to 150 watts, so there is no practical limit at the other end either.

A Matched Pair

These are a genuine mirror-imaged pair, labelled LC and RC. Because the woofer sits on one angled face rather than in the middle, two identical cabinets hung on opposite walls would end up firing in opposite directions relative to the room; the handed pair keeps both oriented the same way about the listening position. It is a real design decision, and it is the reason two singles bought separately are not the same thing as a pair.

Bandwidth

Frequency response runs 50 Hz to 25 kHz, and the cabinet is finished in black vinyl. Polk backed these with a five-year warranty when they were new, which for a surround speaker was unusual and says something about what they expected the cabinets to survive.

Testing

These have been thoroughly inspected and tested to confirm full functionality.

Condition

Cosmetically this pair is graded Very Good.

Speaker Cable to Suit

Because these terminate in five-way binding posts, they are a straightforward match for our Custom Speaker Cable Builder, built to order in the length you need and terminated to suit. Surround runs are usually the longest cables in a system and the most awkward to route, so having them made to length rather than coiling the excess behind the speaker is worth doing properly. Banana plugs, spades or bare wire all work here.

A properly built American-made surround pair, heavier than the models that replaced it, more efficient than both, switchable between bipole and dipole for whatever your room needs, and designed by someone who thought about what happens behind the speaker once it is on the wall. Available for pickup in Kanata, or shipped across Canada and internationally — we have sent equipment to fifteen countries in the past year, each piece packed in-house in 275 lb test double-wall boxes. Live shipping rates for your address are calculated at checkout. Backed by Radique Audio’s Bumper-to-Bumper Warranty and our Perpetual Trade-Back Program. Available for audition by appointment in Kanata.

Polk Audio f/x 500i Specifications

• Type: Bipole/dipole surround speakers, pair, ported triangular cabinet
• Drive units per speaker: Two 1 inch tri-laminate dome tweeters, one 6.5 inch blue composite Dynamic Balance woofer with rubber surround
• Driver geometry: Two arrays at 45 degrees, anti-diffraction raised bezel
• Mode switching: Rear-panel bipole / dipole selector
• Frequency response: 50 Hz – 25,000 Hz (-3 dB)
• Sensitivity: 90 dB
• Nominal impedance: 8 ohms
• Power handling: Up to 150 watts
• Connections: Five-way binding posts
• Mounting: Integrated keyhole slots with moulded rubber wall standoffs
• Finish: Black vinyl
• Country of manufacture: United States
• Original factory warranty: 5 years
• Dimensions each: (Width x Height x Depth) 9.9 x 15.4 x 9.6 inches (252 x 391 x 244 mm)
• Weight: 19.4 lbs (8.8 kg) each

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