Perhaps the most frequently encountered challenge faced by the home music producer is a studio which sounds "boomy". Poor acoustics which cause boomy rooms also present problems to the audiophile and the home cinema user and if untreated can create an unpleasant listening environment for the user.
To understand how to treat the boomy rooms it is important to understand what the causes are first and foremost and then proceed to adopt a suitable strategy coupled with acoustic treatment using high quality acoustic foam to tackle this low end frequency phenomenon. Successfully tackling room boom will greatly improve the quality and portability of your audio material.
The boomy sound is created by amplification of waves of various low end frequencies as they reinforce themselves at different points in your room.When these waves fit squarely in your room a standing wave is observed. A collection of frequencies that create standing waves in a room are called modes. The dimensions of your room will have an impact on the nature and frequencies at which these modes occur.Room modes would primarily occur in any plane where there parallel opposing walls as such would occur along the length, width and height of the room. To complicate things a bit more there are tangential and oblique standing waves are created by sound waves bouncing off a combination of walls and ceilings. Standing waves are more an issue in low frequencies because of the higher reverberant energy and the ability of the energy to persist or take longer to decay. Higher frequencies will decay quicker and as such by the time the reflected wave travels back to reinforce the direct or original wave the residual energy of the wave is very low. Higher frequencies however cause echoes and flutter echoes which will be addressed in a seperate article.
Taming the boom
It is important to realise that any amount of acoustic treatment will not eliminate the boom created but will definitely go a long way in reducing its impact. As such before venturing out to invest in acoustic treatment we recommend you follow these three simple steps
Make the most of the dimensions of your room. Placement of speaker and mixing position within your room can significantly reduce the significance of unwanted modes in your room. Always aim to have your speakers along the shorter wall in your room such that the speakers are firing the length of your room. Also, space allowing, move your speakers away from any corners and walls. Finally try and maintain symmetry in your layout this will help balance out the sound image you receive.
Ensure your monitors are adequately isolated from the surface they are resting on, this includes monitor stands. Working monitors sitting on a desk will invariably force the desk to resonate at its own natural frequency, this would create unwanted colouration in your room muddying the sound and reducing the quality of the sound in your room.A decent set of Monitor isolation pads placed under each speaker. Good isolation pads should be made of a material that is both flexible enough to absorb energy without suffering compression set and resilient enough to prevent the speaker from swaying when in use.
Addressing placement and isolation can in some cases reduce a significant portion of the issues present in your room. Once you have sorted the placement and isolation you can now start to invest in bass traps to further refine your rooms response. Bass traps come in various shapes, sizes and makes. What ever bass traps you settle for ensure you are getting products that have been adequately tested for absorption. A good indicator is the Weighted absoprtion coefficient and sound absorption class. Aim for Class A as this will guarantee you are getting a product that is effective at sound absorption.
Acoustic Foam Bass traps.
Properly designed acoustic foam bass traps are a very cost effective choice and recommended where ease of flexibility and cost are important. The design and quality of foam play a very important role in the performance of the bass traps.
There are manufacturers out there who will try to make you believe that any type of foam will deliver effective bass frequency absorption. These same foam converters will pass off low density matteress grade foam cut in attractive shapes as bass traps. This is simply not the case! Upholstery foam used by comfy mattress manufacturers and converters is simply not effective in dampening low end frequency sound. What may seem like a cheap deal could ruin the acoustics in your room by providing uneven and excessive absorption.
Genuine acoustic foam suppliers and manufacturers will provide full test data and reports to support the performance of their products. Look out for these and ensure standards followed are recognised standards by appropriately accredited test labs. Otherwise any comparison will only result in comparing apples and oranges.
Adopting these three easy steps will go along way in helping you improve the sound quality in your room. Good luck and please don't hesitate to share with us pictures of your studio/ listening room.
Polyester foam is a high grade acoustic foam that consists of a uniform open cell structure which lends the foam well for use in sound absorption. The millions of air pockets formed by the fine structure of this foam effectively absorb the energy of incident waves reducing the impact of these waves on your sound mix. The speciality nature of this foam means it is not an attractive material for foam converters to stock. Our manufacturers test the air flow resistance of the material used in our eXtreme range to ensure structure is uniform.