Acoustic Room Treatment

Quadratic Residue Diffuser/QRD N17 prime

A QRD diffuser comprises wells of different depths, causing a mixture of phase shifts that diffuse reflected sound. They are used to control reflections in the listening environment.
At Hifi Creations we have decided to go for a more complex built and broad-range design. The diffuser is a 17-root with a range from 500Hz – 6800Hz(broad-band as opposed to narrow-band)

Not all diffusers are created equal!
A. The well width determines the upper frequency limit of diffusion. The narrower the well, the higher the frequency it will diffuse.
B. The deepest well in the sequence determines the diffuser’s lower limit. The QRD N17 deep well design is effective down to 500Hz.
C. The higher the prime number sequence, the more even and smooth diffusion will be throughout the audio spectrum.

Advantages of QRD N17 broad-band:
1. add width to your sound stage, so your music will sound like it is coming from farther left and farther right of your actual speaker positions
2. effectively reduce flutter echoes and standing waves
3. excellent alternative to sound absorption(foam type) because they do not remove sound energy, hence ‘live sounding room’ as opposed to ‘dead room’
4. add sense of ‘air’ and retains natural ambience
5. giving the impression of being in a much larger room

Applications: home hifi, high-end home theater, recording studio, performance venues

in a well treated acoustic room, you can hear everything the artist and engineer intended you to hear when they made the recording together. This experience will bring you closer to the artist and give you a far more visceral listening experience than you ever imagined possible.

List Price: RM1600 2 X 4 feet
Finishing: Teak, Walnut, Sen, Zebrano(additional charge for premium materials)
* 2 X 8 feet size available too

2D Diffuser/Skyline Diffuser – Solid wood

Difference between 1D and 2D diffuser:
1D Diffusers scatter energy in a semi-circular pattern horizontally.
2D Diffusers scatter acoustic energy in a hemispherical pattern, both horizontally and vertically.

List Price: RM1600 2 X 2 feet panel


1. Do all diffusers work the same way?

No. Diffusers work by reflecting energy back into the room. Larger, more massive diffusers are able to control low frequencies while thin light-weight diffusers are only effective at controlling higher frequencies. The size, mass and design of the diffuser play a significant role in how it will work.

2. Why do some companies claim their plastic diffusers will be effective at low frequencies?

The world is full of mysteries! As a rule, you can employ quarter-wavelength calculations to predict how a device will work and this can generally be applied to high frequencies. But when it comes to controlling bass, you really need mass. Without mass, the bass will pass right through.

3. Why are quadratic residue diffusers so expensive?

The problem with a ‘true’ quadratic diffuser is that there is no easy way to fabricate one and the sales volumes are simply insufficient to mass produce them like a bookshelf. Primarily hand made, hand glued, hand assembled and hand finished which takes a tremendous amount of time. Thus the reason it is so expensive.

4. Are diffusers or acoustic panels (absorbers) interchangeable?

In some cases they can be. Sound absorption panels remove energy from the room while diffusers retain the energy. by adding diffusers you can create a sense of ‘liveliness’ in the room as opposed to a near total ‘dead room sounding’.

* QRD N17  & 2D Skyline Diffuser is handmade by hifi creations


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