Wednesday, January 2, 2013
Frequency asked questions...
Low Bass: anything less than 50Hz
This range is often known as the sub bass and is most commonly taken up by the lowest part of the kick drum and bass guitar, although at these frequencies it's almost impossible to determine any pitch. Sub bass is one of the reasons why 12" vinyl became available: low frequencies require wider grooves than high frequencies - without rolling off everything below 50Hz you couldn't fit a full track onto a 7" vinyl record. However we do NOT recommend applying any form of boost around this area without the use of very high quality studio monitors (not home monitors - there is a vast difference between home nearfield and studio farfield monitors costing anywhere between £5,000 and £20,000). Boosting blindly in this area without a valid reference point can and will permanently damage most speakers, even PA systems. You have been warned!
This is the range you're adjusting when applying the bass boost on most home stereos, although most bass signals in modern music tracks lie around the 90-200Hz area with a small boost in the upper ranges to add some presence or clarity.
Muddiness/irritational area: 200-800Hz
The main culprit area for muddy sounding mixes, hence the term 'irritational area'. Most frequencies around here can cause psycho-acoustic problems: if too many sounds in a mix are dominating this area, a track can quickly become annoying, resulting in a rush to finish mixing it as you get bored or irritated by the sound of it.
Human hearing is extremely sensitive at these frequencies, and even a minute boost around here will result in a huge change in the sound - almost the same as if you boosted around 10db at any other range. This is because our voices are centred in this area, so it's the frequency range we hear more than any other. Most telephones work at 3kHz, because at this frequency speech is most intelligible. This frequency also covers TV stations, radio, and electric power tools. If you have to apply any boosting in this area, be very cautious, especially on vocals. We're particularly sensitive to how the human voice sounds and its frequency coverage.
High Range: 6-8kHz
This is the range you adjust when applying the treble boost on your home stereo. This area is slightly boosted to make sounds artificially brighter (although this artificial boost is what we now call 'lifelike') when mastering a track before burning it to CD.
Hi-High Range: 8-20kHz
This area is taken up by the higher frequencies of cymbals and hi-hats, but boosting around this range, particularly around 12kHz can make a recording sound more high quality than it actually is, and it's a technique commonly used by the recording industry to fool people into thinking that certain CDs are more hi-fidelity than they'd otherwise sound. However, boosting in this area also requires a lot of care - it can easily pronounce any background hiss, and using too much will result in a mix becoming irritating.