Infinity at Radique
We service Infinity, too. Bring us your own Infinity speakers and subwoofers for repair, servicing or restoration (speakers up to 80 lbs each), with a 90-day warranty on the work. See our Audio Service page

Infinity was founded in Los Angeles in 1968 by aerospace engineers Arnie Nudell and John Ulrick, with Cary Christie, and its first speaker was the electrostatic Servo-Statik. We carry Infinity towers, bookshelf speakers, centre channels and subwoofers. We’ve had more than 45 Infinity listings so far, covering more than 30 different models. Every used Infinity here is inspected, tested and serviced as required, then photographed in-house and covered by our Bumper-to-Bumper Warranty and Perpetual Trade-Back Program. Don’t see the model you want? Tell us on First Dibs and we’ll email you when one arrives.

Our best-selling Infinity models so far: the Beta 40 towers, then the Interlude IL25C centre, IL30 and IL40 towers and IL36C centre.

The Infinity story

Arnie Nudell and John Ulrick, aerospace engineers at Litton Industries, left with Cary Christie in 1968 to build speakers, starting in Nudell’s garage. Their Servo-Statik combined electrostatic panels with a servo-controlled woofer, an idea from their aerospace work, and sold for $2,000 a pair.

EMIT and the reference years. In the late 1970s the Quantum line and the low-priced Qa, Qb and Qe brought in Infinity’s EMIT tweeter, a flat plastic diaphragm with etched conductors, and Stereo Review called the $145 Qa one of the best loudspeaker values on the market. Infinity’s flagship reference systems arrived at the end of the 1970s, and in Canada its speakers came in through Gray Acoustics of Markham, Ontario.

Harman. Infinity has been part of Harman International since the mid-1980s, and Samsung has owned Harman since 2017. The Kappa, Reference, Interlude, Primus and Beta lines followed through the 1990s and 2000s. In North America, Infinity now sells mainly car and marine audio.

Which Infinity is which?

1970s high end: the Servo-Statik, Monitor and Quantum models.

1970s and 1980s budget: the Qa, Qb and Qe, and the InfiniTesimal mini speakers.

Reference Standard and Kappa (1980s to 1990s): many numbered RS models, and Kappa towers and subwoofers.

Interlude (2000 to 2001): the IL10 bookshelf, the IL30 to IL60 towers, the IL25C and IL36C centres and IL subwoofers, with Infinity’s ceramic metal matrix drivers. Infinity lists the IL30 and IL40 as made in the USA.

Primus and Beta (2003 to 2010): such as the Primus 250 and 360 towers, and the Beta bookshelf speakers and subwoofers.

Later lines: Cascade, Classia, TSS and the Reference series of 2014.

Buying used Infinity: what to check

Swap channels first. Infinity’s own advice: if one speaker of a pair is silent or distorted, swap amplifier channels. If the fault follows the speaker, look for a loose wire, a bad crossover or a bad driver.

Crossovers. Inspect the crossover board for parts that look burnt or bulged.

Tweeters. Check that every tweeter, EMIT tweeters included, plays at low and moderate levels.

Powered models. Test the bass amplifier of any powered subwoofer or tower at volume.

Parts. Infinity lists no replacement parts for models such as the Interlude series, so replacement drivers come from donor speakers.

Everything we list is inspected, tested and serviced as required here, and comes with our warranty.

Showing all 7 resultsSorted by price: high to low

Beautiful Infinity Interlude Series Towers w/ Powered Subs IL50

$895.00

Beautiful Infinity Interlude Series Towers with 10″ Powered Subwoofers. Beautiful Infinity Interlude Series Towers with 10″ Powered Subwoofers. Design and

Infinity Modulus MSW-II 12″ Powered Subwoofer – 600W Peak

$495.00

Infinity Modulus MSW-II 12″ Powered Subwoofer – 300W RMS, Silver The Infinity Modulus MSW-II is a high-performance 12-inch powered subwoofer

Great sounding quality 4-Driver Towers from Infinity Beta 40

$495.00

The Betas are our favourite mid-range series from Infinity. We’ve been using a pair of trusty Beta 50’s in our

Infinity Bookshelf Speakers with 6.5″ Woofers RS2

$195.00

A 6.5-inch polypropylene woofer on a butyl rubber surround with a half-inch soft dome tweeter, in a rear-ported MDF cabinet — 50 Hz to 20 kHz, 89 dB, 8 ohms. Rated for 15 to 100 watts, with binding posts on the back. A two-way from the 1990s at 12.2 lbs each.

Infinity Center Channel Video 1 (CS60003B)

$110.00

The front baffle is angled, which is the point: sit it below the screen and it still fires at the seated ear rather than at your knees. Dual 5.5-inch polypropylene woofers and a half-inch polycarbonate tweeter crossed at 4.5 kHz, 58 Hz to 20 kHz, 89 dB, 8 ohms. Rated for amplifiers between 5 and 100 watts. Magnetically shielded.

Infinity Minuette MPS Passive Subwoofer – Dual 6.5″, Front-Ported

$95.00

A passive subwoofer, which means no power cord, no built-in amplifier and no electronic crossover to fail. Two 6.5-inch polypropylene woofers in a bandpass box, 40 to 150Hz, wired high-level — your amplifier's front outputs go in, your main speakers come off the pass-through, and the sub keeps everything below about 150Hz. Twenty-eight pounds of moulded composite. Very good condition.

Sold out

Beautiful Infinity Center Channel in Light Maple IL25C

$195.00

Beautiful Infinity Center Channel in Light Maple Treat your home theater to impressive center channel realism with Infinity’s compact, 2-way

Questions about Infinity

Can you service my Infinity?
Yes. Bring us your own Infinity speakers and subwoofers for repair, servicing or restoration (speakers up to 80 lbs each), with a 90-day warranty on the work. Every job is tested again by a second tech before it goes home. See our Audio Service page for bench fees and how it works.
Is every used Infinity checked before it's sold?
Yes. Every used Infinity here is inspected, tested and serviced as required, then photographed in-house and covered by our Bumper-to-Bumper Warranty and Perpetual Trade-Back Program.
Where does Infinity come from?
Infinity was founded in Los Angeles in 1968 by aerospace engineers Arnie Nudell and John Ulrick, with Cary Christie, and its first speaker was the electrostatic Servo-Statik.
Which Infinity models do you sell most?
Our best-selling Infinity models so far: the Beta 40 towers, then the Interlude IL25C centre, IL30 and IL40 towers and IL36C centre.