Razorblade Quadratic Diffuser FAQ

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. So the size, mass and design of the diffuser play a significant role in how it will work.

Will a diffuser like the Razorblade diffuse all frequencies evenly?

To answer this question, you must first come to grips with the fact that a QRD diffuses energy in both time (temporal) and space (spatial). The energy being spread over time is frequency dependent and is related to the well depths. The greater the primitive root number, the more effective the device will be. As there are an infinite number of frequencies, one would require and infinite number of wells to diffuse them all evenly. The Razorblade like all other diffusers works by diffusing the ¼ wavelength of the frequency and the harmonics.

How come 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.

Will the Razorblade resonate and absorbing energy when it should be reflecting it?

Concrete blocks can be made to resonate. Point being, the question really depends on the frequency. The Razorblade’s rigid construction and heavy mass will not resonate within the specified working range. It will resonate in the lower bass region but this will likely help eliminate low frequency room modes.

I noticed some companies put mini diffusers into larger ones. Why?

This is actually a clever design. It is like combining two loudspeakers into a cabinet to create a full range sound. To predict how effective they will be, you merely need to measure the width and depth of the wells. If for instance they have two series of wells where the large ones are 6” deep and 3” wide and the smaller inner wells are ½” wide and ½” deep, the deep well will effectively perform from 650Hz to 2260Hz while the second well will be effective from 6kHz to 27kHz. The concern here is that there may be a huge dip in the performance between the 2khz and 6.7kHz region.

Why are quadratic 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. The Razorblade is primarily hand made, hand glued, hand assembled and hand finished which takes a tremendous amount of time. Thus the reason it is so expensive.

Can I make my own quadratic diffuser?

Of course. There are plenty of resources on the web that show you the math and the process on building one. If you have lots of time and are handy with a wood shop and tools, building a quadratic residue diffuser can be fun and rewarding.

How are diffusers actually tested?

Diffusion is extremely difficult to test. There are some laboratories that try do so by using an arc’ed array of microphones. We chose to test the Razorblade using advanced computer modeling. The engineer that did the testing employed the same process as used by the aerospace industry.

Are diffusers of acoustic panels (absorbers) interchangeable?

In some cases they can be, but for the most part no. Sound absorption panels remove energy from the room while diffusers retain the energy. Most studios employ a mix of both to create the desired work environment.

Are grid-like devices like the Primacoustic Radiator and Auralex Space Array true diffusers?

No. These are very simple reflectors that are designed to scatter energy in the room. These cost about one quarter the price of a true quadratic residue diffuser making them an affordable option. They are not as effective but will do a pretty good job at breaking up energy from around 550hz to 2.2kHz.

Where is the best place to position a Razorblade in a room?

Top end studios tend to place their Razorblades behind the listening position so that when the room is excited (sound being played) the result is a more natural reverb trail. These generally span the width of the work surface and take up the upper portion of the wall.

Can I buy a Razorblade without it being painted or in a custom wood?

Not unless you are buying over 12. If you are, simply contact our customer service desk and we will provide you with a custom quotation.

Can I refinish a Razorblade in a different color?

Not easily. They are painted black as this is the easiest color to integrate into most rooms. You can try repainting them if you like, but you will surely need several coats. The good news is that repainting them will have no effect on the acoustic performance.

Is the Razorblade tested to meet Class-A fire & smoke?

The Razorblade is made of wood. As such, it will be treated like any other wood products such as a shelf or table and is therefore not required to be tested as one would with plastics or other non-wood construction materials. If you are unsure about the building codes in your city, simply contact your municipal disinterring office and then can advise.

How do you ship the Razorblades?

As a means to avoid damage in transport, we tend to always ship Razorblades using pallets and trucking companies. This of course costs more than shipping by common courier, but the added costs and greater protection afforded by the pallets usually mean the Razorblades will arrive safely.