Decibels, Frequencies, Format Comparisons

DECIBELS

0 dB: the "threshold of hearing"...or the faintest sound an average person can hear

10 dB: the sound of a pin dropping from one yard away

20 dB: soft whispering...or the hum of a refrigerator

30 dB: the sound level of a library

40 dB: a quiet conversation

50 dB: a teacher speaking to a class in a medium-sized classroom

60 dB: the sound level of a busy office...or a sewing machine

70 dB: a vacuum cleaner...or a blow dryer...or a busy sidewalk

80 dB: a laundromat...or an alarm clock (may appear to be louder on Monday mornings)

90 dB: the volume of a lawn mower. To protect your hearing, you should expose yourself to no more than 8 hours per day of sound at this level (not an excuse to avoid mowing the lawn)

100 dB: a large orchestra playing loudly...or a chainsaw...or a person yelling as loudly as they can, for whatever reason (limit exposure to 2 hours per day at this volume level. And see what's wrong with that person)

110 dB: a rock concert...or a car horn...or a motorcycle...or a jackhammer (no more than 1 hour per day at this level)

120 dB: a car stereo at full blast...or a conversation between teenagers at the next table in the restaurant (maximum of 15 minutes a day at this volume level)

THE FOLLOWING VOLUME LEVELS ARE IN THE "DANGER ZONE" -- AVOID ALL EXPOSURE IF POSSIBLE:

130 dB: loud headphones...or a jet taking off from a few blocks away (physical ear-pain begins at this level)

140 dB: a fire cracker explosion up close

150 dB: an M-80 or cherry bomb explosion up close

FREQUENCIES

20 kHz: Not much of musical value happening up here, except the very highest overtones of treble instruments. Some extremely high-pitched noise lives here, too. The average person can't hear anything above this frequency, and many adults can't even hear this one. Some engineers prefer to filter everything from here up completely out of a mix.

around 16 kHz: Very high overtones. This region is the key to a sense of "air" and "liveness" in your music. It also helps your ears detect exactly where things are placed in a mix. Sampled instruments (such as drum machine sounds, keyboard tones, etc.) usually don't contain frequencies this high, due to technical limitations. That partly explains why they sound so artificial; however, a device called the Aphex Aural Exciter can be used to generate extra overtones on them, making them sound more realistic. It works by examining the frequencies which are already present in the sound, and then creating new, mathematically-correct harmonics over them, to replace the ones that are missing. The result is an instrument sound that is very much like the original. I describe this device more fully on the MY STUFF page. There are other enhancing tools on the market; however, to my knowledge, the Aphex is the only one that actually generates new overtones. The other ones use different techniques to brighten sounds.

around 12 kHz: High treble. Most quality-brand stereos can handle overtones at least this high. This region contains the "shimmer" and "sparkle" of a mix. In the interest of reducing hiss and other high-frequency noise, a few engineers will roll off everything above this range, although doing so robs the mix of the "live" sound quality mentioned above.

around 10 kHz: The sizzle of high hats and cymbals is mainly found here. Also, the vividness of guitars, pianos and vocals. A very important range for treble response in consumer audio equipment -- this frequency is often used as a benchmark to determine whether a piece of gear is good enough to be considered high-fidelity. However, a music program that cuts off everything above 10k won't necessarily sound "lo-fi"; in fact, the average person won't even notice anything is missing, especially after listening for a while.

around 9 kHz: A little lift here gives detail and seperation to individual voices in a vocal ensemble. Also useful for enhancing the expressive raspiness of some lead singers.

around 8 kHz: Try boosting here to accent phasing and flanging effects. Can also be used to shine up your brass instruments.

around 7 kHz: The brightness of toms; the buzz of string ensembles and sawtooth- wave keyboard sounds. Cut slightly to cope with excessive finger noise on stringed instruments, or sibilance (edgy "s" sounds) on a vocal.

around 6 kHz: The brightness of a kick drum or bass guitar; the whispery quality of a vocal (don't go overboard boosting here...it can lead to thin-sounding voices!).

around 5 kHz: The buzz of a snare drum; the presence of high-hats, guitars and female or child vocals. ("Presence" refers to how close to the listener things in a mix appear to be.) Solo piano, whether acoustic or electric, sounds more luxurious with this region raised up a bit (perhaps 4 dB), along with 250 Hz. Also, a slight dip here helps with surface noise problems on your old phonograph records.

around 4 kHz: Probably the best spot to boost for presence on a male vocal. Start with 4 - 6 decibels (fairly wide Q) and experiment from there.

around 3 kHz: The presence of a kick drum; the string noise on a bass guitar; the edginess a guitar solo needs to cut through a mix. A piano can gain independence from the rest of the band with a gentle boost in this area. A mild dip here controls screeching notes from a female or child singer.

around 2 kHz: The sharpness of a snare drum. A key region for dealing with the ear-grating harshness that may occur on guitars and vocals. (Dabble around until you pinpoint the exact frequency that's irritating you, because cutting too much here can make it hard to understand the lyrics in your vocal...or zap the life out out your guitar. If you're not sure about what you're doing, it's probably best to leave this region alone -- there's too much at stake!)

around 1 kHz: The noise of a pick used on any stringed instrument; the honking quality of most instruments; the telephone-like quality of vocals; the attack and pitch definition of a bass guitar or upright bass. Dip here to tame piercing notes on a male vocal.

around 500 Hz: The body tone of a guitars (acoustic or electric), organs, and many orchestral instruments like violins, woodwinds, and brass. Too much energy here can make a mix sound "boxy"...as if your speakers were made of cardboard.

around 450 Hz: The chest-voice of female and child singers.

around 400 Hz: The chest-voice of male singers.

around 350 Hz: The body tone of toms.

around 300 Hz: The general sense of warmth and fullness in a mix. If you boost here, use a Q setting that's not wide enough to pick up 200 Hz -- he's a troublemaker, as you'll see below.

around 250 Hz: The warmth of things like electric guitar, synth pad, string pad and (solo) piano.

around 200 Hz: The body tone of a snare drum. A slight cut here will help deal with muddiness on just about any instrument, voice, or mix, and will prevent any competition with the snare.

around 150 Hz: Here's a useful secret: cut a few decibels in this area to make the bass sound more punchy on a mix or individual instrument. If your EQ is sweepable, experiment to find the exact spot that sounds best. (Of course, this only applies to instruments that actually have something happening down here -- not a tambourine, for instance.)

around 100 Hz: The bass energy of a kick drum. Also, the low end of an electric guitar, piano or musically-acceptable synth tone. You probably don't need anything below this on a non-bass instrument, so filter out the lows to keep them from fighting the bass guitar. Put a big boost here if you want to imitate the voice of a radio DJ.

around 50 Hz: The lowest notes of bass instruments. This range is the key to powerful-sounding mixes; boosting it a couple of dB can give your music a sense of "phatness" (weightiness) as long as you don't overdo it. You can clarify your rhythm section by adding a few dB anywhere from here to 80 Hz on your bass guitar, while cutting a few from your kick drum. Cut here if you're having trouble with AC hum and you have no other way of getting rid of it.

10 - 20 Hz: The extreme lower range of hearing for most adults. You are usually advised to filter out everything from here down when you're recording onto analog tape; doing so often improves the results. You can leave this range alone for digital recordings, or remove it -- whichever sounds best to you. Keep in mind that, in most cases, anything this low is probably just taking up valuable recording space, forcing you to compromise the volume level at which you can record the more important things in your mix. (Suggestion: get rid of it.)

FORMAT COMPARISONS
ALL ARE APPROXIMATE

human ear capacity: Dynamic range = 100 dB. Frequency response = 20 Hz to 20 kHz.

DVD: Dynamic range = 106 dB (* see note). Frequency response = 0 Hz to 20 kHz.

CD / DAT: Dynamic range = 96 dB (* see note). Frequency response = 0 Hz to 20 kHz.

MiniDisc: Dynamic range = 96 dB (* see note). Frequency response = 0 Hz to 20 kHz.

12-inch vinyl: Dynamic range = 20 dB (* see note). Frequency response = 50 Hz to 22 kHz.

7-inch 45: Dynamic range = 20 dB (* see note). Frequency response = 50 Hz to 12 kHz. (Usually were either vinyl, shellac, or polystyrene.)

TV / hi-fi VHS / FM radio: Dynamic range = 60 dB (* * see note). Frequency response = 20 Hz to 15 kHz. (NOTE: Ordinary "non-hi-fi" VHS sounds only about as good as a normal cassette.)

metal cassette (Type IV): Dynamic range = 65 dB (with Dolby B = 70 dB; with Dolby C = 80 dB.) Frequency response = 20 Hz to 18 kHz. (The tape is layered with fine metal particles. Sounds excellent, but is somewhat abrasive on tape heads. Also tends to snap easily.)

ferro-chrome cassette (Type III): (This mixture of metal and chrome oxide particles was an experimental format that never caught on. Went the way of the eight-track cartridge. By the way, there is a Type 0 too, that is likewise disappearing. It is similar to normal tape in formula, but apparently has some problems.)

chrome cassette (Type II): Dynamic range = 60 dB (with Dolby B = 65 dB; with Dolby C = 75 dB * see note). Frequency response = 20 Hz to 16 kHz. (Formulated of a substance derived from chrome, which is then mixed with iron rust particles. A fine compromise between great sound and tape head-friendliness.)

normal cassette (Type I): Dynamic range = 55 dB (with Dolby B = 60 dB; with Dolby C = 70 dB * see note). Frequency response = 20 Hz to 14 kHz. (Made with ferric oxide - the rust that comes from iron. Sound quality is acceptable; material is very easy on tape heads.)

MP3: Dynamic range = 20 dB (most people don't utilize this full range -- they heavily compress). Frequency response = 20 Hz to 12 kHz.

AM radio: Dynamic range = 30 dB (* * see note). Frequency response = 20 Hz to10 kHz.

typical home stereo speaker: Dynamic range = 90 dB. Frequency response = 80 Hz to 20 kHz.

typical cheap computer speaker: Dynamic range = 70 dB. Frequency response = 200 Hz to 15 kHz.

NOTES:

* Most popular music releases are compressed to about 20 - 30 dB, regardless of the dynamic range the format is capable of handling. In the days of vinyl, this was done for the purpose of getting the sound acceptably recorded onto the records. Too much dynamic energy was detrimental to these discs; it messed up both the recording and the playback, because it made the needles jump out of the grooves. Due to this, the stereos that were made to play these records were designed to handle no more than this narrow dynamic range...anything more would have been unnecessary. (It never occurred to them that one day we would develop a format which could handle a wider range -- namely, the CD). Today, we have several formats which are capable of HUGE dynamics, yet we still use with stereo systems that have narrow dynamic range capability. Why? Because we have become so accustomed to hearing highly-squashed music, most of us are turned off by recordings with natural-sounding dynamics. Que loco.

* * Major commercial TV / radio stations routinely compress their broadcasts to less than 10 dB. This is done for two reasons: (1) to make their station sound as loud as the competition; and (2) to keep their volume level steady so you don't have to constantly adjust your stereo. (Don't kid yourself...it's mainly the first reason.) They use multi-band compression to keep the sound from getting too smeared. A multi-band compressor is one that isolates the bass, midrange and treble portions of a sound and allows you to compress each band seperately, so nothing gets more treatment than it needs. Generally, bass is compressed fairly heavily; midrange to a lesser degree; and treble very slightly if at all. This is all followed by an overall limiter, which prevents anything from getting through above the safety margin.

human ear capacity is higher than 100...

120 is the level where pain begins

and you cannot hear anything below 20hz

.pz.

It's only an approximation. This info varies from person to person.