Golden Ratios
Some of you may have heard of the term ‘golden ratio’ when referring to studio design. This is the ratio between the height, width and length of a room. If you are lucky enough to be in a position to ‘choose’ the dimensions of your room, then you may consider using the golden ratios to do so.
Originating from ancient Greece, these ratios have been applied in many subjects and practices; from architecture to classical music, and even to book design. They also occur frequently in nature which is how they were first discovered.
In regards to studio design, the golden ratios are a proven way to obtain a more accurate listening space as they allow for a uniform distribution of resonant frequencies around the room (yes, resonance still occurs).
As for how they are calculated, the level of mathematics is probably too advanced for this mastering tutorial. In any case, the purpose of this mastering tutorial is to show you how to achieve a professional finish by utilizing what you already have. So rather than have you build an extension on the side of your house, let’s move on to how you can transform an existing room into a reliable listening environment.
Surface Material
A surface material will have different reflective characteristics depending on the frequency of the sound wave hitting it.
A soft surface material such as carpet will absorb much of the higher frequencies preventing them from being reflected back into the room. However, a low frequency will pass straight through the carpet to the reflective solid surface beneath. A heavy drape may provide control of midrange and higher frequencies but again, the lower frequencies find their way through.
Controlling the lower frequencies requires more elaborate efforts than the use of things like drapes, or carpet; their long wavelengths require the use of much larger objects.
Just before we reach the discussion on how to control these troublesome reflections, I’d like to point out one more issue you will face – the ‘hanging around’ effect of the lower frequencies caused by the solid surfaces beneath the soft furnishings reflecting the sound waves back into the room, and the resonating ‘trapped’ lower frequencies which subsequently take longer to disperse their energy.
The result is a lack of definition in the low end as the sonic information literally starts to smear.
So we know that the room’s reflections alter the perceived speaker sound. Should we attempt to ‘remove’ the reflections from the room? Fortunately, it’s okay to have some reflections in the room, we just need to ‘neutralize’ them the best we can so we can trust the speaker’s sound.
Room Contents
Before you begin budgeting for acoustic treatment, there’s a lot that can be done using the everyday things around you.
As well as audio gear, the room will most likely contain some furnishings which will aid the absorption of reflections, as well as irregular surfaces that serve to break up and scatter incoming sound waves, preventing them from building up and appearing louder in certain areas of the room.
As mentioned, lower frequencies are more of a problem as they can travel straight through thin coverings like curtains and carpets which are effective against high frequencies. Large furniture with soft surfaces such as beds, sofas and padded chairs all soak up a certain amount of the lower frequencies because their material is porous but quite dense, so although the powerful low-frequency energy is able to enter the material as vibration, a lot of the energy is dispersed as friction and heat. This is similar to how professional ‘bass traps’ work – the vibrations cause the fibers inside the dense mineral wool filling to rub together converting kinetic energy into heat.
Half-full bookshelves, angled sofas, a laden coat stand, an open wardrobe, anything that is either absorptive or uneven – and may help to divert and fragment the direct speaker sound – is a worthwhile consideration.
