We are Joe's Studio Monitors

By Greg Simmons

Hello, we are Joe's studio monitors. We're the most important part of Joe's studio because all of his recording and mixing decisions rely on the sound we reproduce. Unfortunately, Joe doesn't know how to get the best performance from us, so he's never happy with our sound and his mixes always need a lot of mastering.

We're actually very good monitors, but Joe has never heard the quality we're capable of because his room sounds ordinary and we're not set up correctly in it. From the moment the sound leaves our boxes it's at the mercy of his room's acoustics (which alter the sound Joe hears by more than 12dB at some frequencies!), and there's nothing we can do about it. Joe doesn't want to accept this fact, of course. He wants to believe that studio monitors are magic boxes that can be placed anywhere in the room and sound the same. Sorry, Joe, but you can't ignore the laws of physics.

We wish Joe would learn a bit about acoustics. He could start with resonance, which occurs between any two opposing surfaces (i.e. walls) that are solid enough to reflect sound. Contrary to popular belief, they don't have to be parallel! Resonance begins at the frequency whose half-wavelength equals the distance between the opposing surfaces, and continues at all whole-numbered multiples of that frequency. When a frequency is resonating, there'll be points between the opposing surfaces where it will be up to 6dB louder than other frequencies (for example, against the surfaces themselves) and points where it will be virtually non-audible. How loud Joe hears a resonant frequency relative to other frequencies depends on the location of his studio monitors and his listening position. With careful juggling of monitor and listening positions it's possible to create an optimum response, but it's tricky because it happens in three dimensions. RPG's 'Room Optimizer' software makes it much easier.

To make matters worse, Joe has carelessly stuck one of us in a corner. Apart from this setup not being symmetrical (Joe thinks 'symmetry' is a place for dead people), corners are the worst places to put monitors because they represent a junction of two or more surfaces, and therefore two or more resonance peaks. No wonder we sound boomy! (Tip: rolling up a duvet or heavy quilt and placing it upright in a corner helps to tame resonant energy) .Although we're high quality monitors with smooth low frequency performance, the resonances in Joe's room make us sound boxy and cheap.

After optimizing his monitor and listening positions for the smoothest low frequency response, Joe should learn about reflections. The first sound Joe hears is that which takes a direct path through the air from one of us - his studio monitors - to his ears. This is known as the 'direct sound', and is followed by numerous reflections off nearby surfaces. These happen too quickly to be perceived as separate sound events, so Joe's ear/brain system combines them all into the same sound. Each reflection is a delayed version of the direct sound, and, whenever a sound is combined with a delayed version of itself, 'comb filtering' occurs, creating large peaks and dips throughout the frequency response.

The most problematic reflections are called 'first order reflections', because they have only reflected off one surface and are therefore the strongest. In Joe's untreated room they make vocals sound nasal and hollow, snare drums harsh and barking, and guitars lifeless and thin. Joe could find these nasty first order reflection points by using the 'mirror trick' - while seated in his monitoring position, he could ask a friend to move a small mirror flush along each large surface of his room (walls, ceiling, etc.) until he saw one, or both, of us monitors reflected in it. Each visual reflection point is also a first order sound reflection point, and ought to have at least 60cm x 60cm of absorption placed over it. This will have a dramatic effect on the perceived sound, especially in the crucial midrange. But this all looks too hard to Joe. As a result, the midrange in his room is nowhere near as clean and smooth as the midrange we're actually producing, and, of course, it badly affects his mixes.

Finally, after taking care of resonance and reflections, we hope Joe learns about reverberation. The sound energy we produce enters the room, reflects around, and - assuming the energy we produce remains constant - builds to a steady-state level determined by the internal volume of the room and the amount of sound absorption in it. This is known as "reverberant energy', or simply 'reverberation'. When we stop putting sound energy into the room, the reverberation decays away at a rate known as the 'reverberation time'.

Joe's room has no acoustic treatment and too much reverberation. Apart from making it difficult to judge how much reverb is actually in the mix, the excessive room reverberation blurs the high frequency detail and makes us sound bad. Joe inadvertently compensates for this 'misinformation' by adding too much high frequency boost in a futile attempt to make the mix clearer. The real solution is to add more absorption, but it has to be done carefully and is a job that's best left to an acoustician.

By the time you read this we'll be gathering dust on the 'pre-loved' shelf at Joe's favorite hi-tech music store, because he's trading us in for a new pair. He does this on a regular basis as part of his quest to find the perfect studio monitors. He's going to keep wasting his money though, because he refuses to understand the crucial interaction between his studio monitors and his room. Joe desperately wants to believe that studio monitors are magic boxes that can be placed anywhere in the room and sound the same. To believe anything else seems like hard work to him, and he'd never think of consulting an acoustician to help out - they're too expensive, aren't they?