Atlantis Lab AT23 Floorstanding Speakers (Pair)

The Atlantis Lab AT23 is a floorstanding speaker with a horn tweeter and two 21 cm woofers that plays deep and dynamic even with small amplifiers, thanks to 96.5 dB sensitivity and a frequency range down to 33 Hz.

The French manufacturer Atlantis Lab, founded in 1998 by Eric Buy, runs the AT23 as one of the core towers of the range: 1 metre tall, 32 kg each, with drivers from Eighteen Sound.

Why the AT23?

A 1-inch compression driver in the 90×90° horn (called a Dolby Atmos horn by the manufacturer) provides directness in the treble. Below it work two 21 cm paper woofers, one of them with a neodymium magnet. The bass reflex tuning is adjustable: 23.0 cm is set at the factory, and the manufacturer lists further steps from 19.5 to 26.5 cm. That way you adapt the bass to the room, not the other way round.

What you'll hear

The data sheet promises a lot: 33 Hz to 20 kHz, 96.5 dB and a power handling of 300 W. The ecoustics.com test shows how the AT23 performs in practice (see below). If you thought decent low-end extension needs a subwoofer, prepare to be surprised.

Who is the AT23 for?

For listeners who want dynamics, deep bass and sensitivity in an elegant tower, also with tubes or amplifiers ranging from a few watts up to 300 W. Plain talk: at 32 kg each, the AT23 is no lightweight, and as a passive speaker it needs an amplifier that drives 4 Ω cleanly. For a very small room it is simply too much speaker.

Our verdict

A floorstanding speaker with high sensitivity, adjustable bass and a frequency range that handles a lot without a subwoofer. It wants space and an amplifier with control over 4 Ω, and rewards that with speed and depth.

What the press says

ecoustics.com, August 2026 (paraphrased): The reviewer played the AT23 both with a Dynaco ST-70 at 32 W and with a Mark Levinson No. 23.5 at 400 W. He measures a low-bass extension of around 28 Hz at −1 dB, i.e. lower than the stated 33 Hz, and considers a subwoofer superfluous in most music setups. The AT23 is compared with the Vandersteen Treo CT.

Technical specifications

• Type: Floorstanding speaker (passive)
• Tweeter: 1″ compression driver with horn (90 × 90°)
• Woofers: 2 × 21 cm paper (one with neodymium)
• Frequency range: 33 Hz – 20 kHz
• Sensitivity: 96.5 dB
• Impedance: 4 Ω
• Power handling: 300 W (peak 600 W)
• Recommended amplifier power: 6 – 300 W
• Bass reflex: adjustable (factory 23.0 cm; steps 19.5 / 21.5 / 23.5 / 26.5 cm)
• Binding posts: pure copper
• Dimensions (W × H × D): 25 – 31 × 100 × 33 cm (tapered cabinet)
• Weight: 32 kg each (pair: 64 kg)
• Break-in time: approx. 100 hours
• Finish: faux leather black or beige with oak
• Warranty: 7 years (manufacturer warranty)

Frequently asked questions

Do I need a subwoofer with the Atlantis Lab AT23?
In most cases no. The manufacturer quotes 33 Hz, and ecoustics.com measured around 28 Hz at −1 dB. Whether that is enough in your room depends on its size and your music. We are happy to clarify that in a conversation.

Which amplifier suits the AT23?
The manufacturer quotes 6 to 300 watts, at 96.5 dB sensitivity and 4 Ω. The AT23 plays with small amplifiers and with powerhouses. What matters is that your amplifier drives 4 Ω cleanly. We are happy to check that for your setup.

What does the adjustable bass reflex port do?
It lets you tune the bass to your room. 23.0 cm is set at the factory, and the manufacturer lists further steps from 19.5 to 26.5 cm. Which setting sounds best in your room, we are happy to discuss with you.

Does the price apply to a pair?
Yes, the price applies to a pair, i.e. two speakers for classic stereo. At 32 kg each, transport is a consideration. We are happy to advise you on delivery and setup.

Why buy the Atlantis Lab AT23 from HD Zürisee?
Because we think of speakers, amplifiers and cabling as a system. As a hi-fi specialist in Wädenswil we advise you on room, amplifier and placement. Call us on 044 680 22 00 or write to us on WhatsApp at 076 534 22 00.

Goes well with

You will find the matching amplifier under integrated amplifiers or streaming amplifiers and the right cable under cables & connectors. More from the manufacturer is at Atlantis Lab.