The RUEL R+ is the first and only modular wide-constant-dispersion full-range & crossover-free line-source system.

We know that’s a mouthful, but it’s worth knowing that this is a technological world premiere, while also being a system that looks and sounds entirely natural in most living environments.
As such, the R+ could well be the beginning of a new era in the field of audio reproduction.

Once you experience unadulterated music from any position in a room, the addiction to that live feeling will require it going forward.



Everything is physics and math.
— Katherine Johnson

Walk around the room!

It can seem strange at first, but the R+ system do not seem to get much louder as you get closer to it.

Most regular speakers are point-source, whose sound expand away from the speaker as an ever-enlarging sphere.

With our line-source system, the sound doesn’t expand in the vertical dimension, and radiates outward in a cylindrical fashion.

In technical terms, the sound is attenuated in a linear way rather than as the square of the distance.

In more common language, the perceived volume is quite uniform throughout the listening area.
This is a big advantage when entertaining, since even in a large room you can set a single volume that supports conversation for all… even those close to the speakers.

Think of the waves on the shore, they act as a natural horizontal line-source, this is why can we hear the sound of waves even from far away.

The RUEL R+ is a speaker design for those who enjoy sharing music, not necessarily for those who feel good music only comes from having your ears within a few square inches of space.

Elimination of the floor to ceiling resonances

The R+ uses the floor and ceiling reflection to create a line-source.

The floor and the ceiling become part of the system and virtually disappear.

Dips and resonances (modes) are eliminated.

This, combined with fast responsive small drivers, leads to extreme low frequency precision.



The sun does not shine for a few trees and flowers, but for the wide world’s joy.

Wide view

The RUEL R+ is designed to be as wide and smooth as possible on all frequencies.

On top of using small drivers, the R+ uses a diffraction slit and boast a wide 180 degrees dispersion in the high frequencies.

And because the system is designed to be placed against the back wall, the low frequencies dispersion is also limited to 180 degrees.
Hence, it is a constant dispersion system when placed in the room.

With such a wide dispersion, the speakers don't need to be angled or toed in. 

The shape of the cabinet itself is also round with no diffraction that would otherwise cloud the view.

Image clarity

The wonderful imaging of the RUEL R+ lets you audibly locate the entire characteristic sound of each instrument more accurately in space and the details are simply magic.
The full range of frequencies are radiated from the same full-range drivers that are all in the same vertical line.

In the horizontal dimension, the sound seem to come from almost anywhere but the speakers.
Sounds can be located in a wide horizontal area.


Crossover-free & Full-range

Simplicity is the ultimate sophistication.

The R+ is a one-way system.

There is several advantages to create a one-way system (without crossover):

• less signal manipulation means less distortion

• no interference between different drivers and frequency bands

• no tone difference between driver types

• smooth dispersion vs frequency characteristic

The result is a sound that is transparent, natural, and easy to listen to.

The continuity of the even the frequency response of the RUEL R+ is simply addicting.

The R+ system reproduces frequencies from 38Hz to 19kHz in a buttery smooth manner.

One can listen to music for a long time without listening fatigue.



For me, stories are like Lego blocks. If I don’t put one down, I can’t put the next one down.

To take advantage of the line source characteristics, the R+ needs to run from floor to ceiling.

Each room being different, the R+ is designed as modular system while indulging the continuity of the line.

This allows to create the perfect set-up for a wide range of home environment.

They R+ system is comprised of individual modules easily stacked upon one another, making both installation and integration a breeze.


Audio Line-source History


In 1940, in his book called “Elements of acoustical engineering”, Harry Ferdinand Olson already talk about the theoretical concept of an acoustic line source.



Starting in the 50s, column speakers were used as public address systems because they could direct the sound over a wide horizontal angle and a very narrow vertical angle instead of dispersing it where sound was not wanted or needed. This reduced the amount of reverberant sound and increased intelligibility in large rooms and auditoriums. It also reduced the possibility of acoustic feedback to the microphone. The response did not cover the entire frequency range but was adequate for voice range.



Harold Beveridge was probably the first to create a line source system to cover most of the frequency range in 1965.
It was also the only one before RUEL to create a wide dispersion, one-way, line source system!
It was using an electrostatic driver, a lens and an Helmoltz resonator (bass reflex).
The system was complicated to build, expensive and cumbersome but the Beveridge Cylindrical Sound System (BCSS) was universally acclaimed as the Rolls Royce of loudspeaker systems.
It was commercialized in 1973.

Harold Beveridge criteria for his speakers:

  • It was a full range electrostatic system: no crossovers.

  • It was full height: at least 3/4 of the distance from floor to ceiling.

  • It was full Width: 180 degree dispersion, starting essentially at the wall.

50 years later, and without knowing the Beveridge system in the first place, RUEL criteria:

  • full range dynamic drivers with no crossovers.

  • more than 80% of the floor to ceiling distance

  • wide 180 degree dispersion for all frequencies



In the 70s, Roger Russell, who was working at McIntosh, designed the XTR20, a 3-way system, which was a line source for the high-frequency drivers only.

Several designed followed, the XTR22, XTR18, then full 3-way line source, the XR290.

The XRT2 is the current 3-way line source system from McIntosh.



In the early 90s, researches of the French Dr. Christian Heil, better defined the requirement to create a true line source with several dynamic drivers.

His researches were applied to large PA system with his brand L-Acoustics.



Roger Russell leaves McIntosh in 1992, but never created the system that he really wanted.
In 2005, he continues his researches and creates a crossover-free line source system using dynamic drivers, the IDS-25.

However, the IDS-25 has 3 problems:

• it is not a line source for the high frequencies and creates comb-filtering
• the directivity index grow rapidly in the high frequencies, the directivity is not linear
• it is still cumbersome



50 years after the first Beveridge system, RUEL creates the R+.

We believe that the Harold Beveridge criteria are right.
We believe that a crossover free, wide dispersion line source system is what is needed to create an accurate sound reproduction in a room.

We also believe that the RUEL R+ comes even closer to perfection.
RUEL meets the criteria completely differently, with the last technology, in a more controlled and compact way.

It uses full-range dynamic drivers, a diffraction slot for a wide dispersion, passive radiators, a DSP optimized frequency response, and a state of the art amplification system.

The R+ is also modular, can be adjusted to the ceiling height, is easy to ship, and is beautiful.

Our system was first shown in 2017 and the R+ is commercialized since 2018.

The RUEL R+ is a new beginning in sound reproduction.