Pro Audio Reference


Pro Audio Reference (StyleGuide)

Pro Audio Style Guide

Last Updated August 2016

Compiled & written by Dennis A. Bohn


Clarity in communication is the whole point of technical writing. It is the important thing in any kind of writing but it is particularly important in technical writing. And a clear understanding of terminology and its style is an important part of clarity. Many style guides exist to help you write clearly and accurately but there are nuances to technical writing, particularly pro audio technical writing that deserve a separate style guide. This represents an easy-to-use look-up reference for troublesome terminology, abbreviations and style conventions for pro audio.

This is not a dictionary; it is a style guide. In general you will not find definitions of terms, only the preferred way of writing and abbreviating for pro audio writing.

And it does not begin to cover all that is necessary for writing accuracy. It only covers the most commonly seen mistakes in pro audio writing. For all the gritty detail I recommend Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers (Reference 3).

Pro audio writing does not differ significantly from other technical writing but there are preferences and idiosyncrasies that cause trouble and uncertainties. Most answers come from the Guide for the Use of the International System of Units (SI) (Reference 5), where many pro audio terms and units are found. These are listed here along with the (many) exceptions.


1/3-octave is with a hyphen and all lowercase. 2/3-octave follows the same rule. Abbreviating 1/3-oct. and 2/3-oct. is acceptable for space considerations.

1/3-octave (or one-third octave) is correct when referring to ISO frequency spacing. “Third octave” is incorrect. See: third octave.

1/4" TRS (tip-ring-sleeve) or 1/4" TS (tip-sleeve) all caps with a space, never lowercase or with a dash.

2-way, 3-way, etc., always hyphenate.

10Base-T, 100Base-T and 1000Base-T always uppercase “B” and one word with a hyphen.

16-bit vs. 16 bits “16-bit” is used as an adjective to describe a product, such as “a 16-bit converter,” and always uses a hyphen. “16 bits” is used as a noun, as in “the unit has 16 bits,” without the hyphen. Also see trick here.

a versus an. Use a before words that start with a consonant sound and an before words that start with a vowel sound. This is more general than the old rule that you put a before words that start with consonants and an before words that start with vowels. For instance, an hour is correct, because hour starts with a vowel sound. The letters o and m can be tricky. For example, it is a Mackie mixer but an MA 4 Rane amplifier. Usually you put an before words that start with o, but sometimes you use a. For example, it is a one-bit converter, because one-bit starts with a w sound. Remember it is the sound that governs whether you use a or an, not the actual first letter of the word. Other trouble spots are words and terms starting with the letter r. It is an RS 1 since this begins with a vowel “arr” sound but it is a RAP 10 because it begins with a consonant “r” sound.

Abbreviations & Periods

  • When a term is derived from a persons name and abbreviated, then it is capitalized; however, when the same term is spelled out, it is always lowercase. For example, it is watt when spelled out, but it is W when abbreviated. Such terms appear throughout this document in alphabetical order.
  • Abbreviations using lowercase letters such as, etc., e.g., and, i.e., require commas and periods as shown. Use a comma before and after and periods for each abbreviated word.
  • Use periods for normal abbreviations like Eq. (equation), Fig. (figure), Prof. (Professor) but not when it is a contraction ending with the final letter of the word, e.g., Dr (Doctor), Mr, (Mister) and Ltd (Limited) do not get a period.
  • Omit the periods when abbreviating titles such as CEO, CTO, CFO, etc., and well-known organizations like AES, IEEE, ASA, etc.
  • Do not begin a sentence with an abbreviation.
  • Use the complete name of a word or phrase at least once before giving the abbreviation within parenthesis. For example, I belong to the Audio Engineering Society (AES). Use the abbreviation for all subsequent usage.

active high (low) vs. active-high (low) “Active-high” is used as an adjective to describe a product, such as “an active-high logic block,” and always uses a hyphen. “Active high” is used as a noun, as in “the logic rule is active high,” without the hyphen. Rule: use the hyphen if it precedes a noun and omit it when it follows a noun.

AES (Audio Engineering Society) Standards and Information Documents numbering style

  • Standards and Recommended Practices are represented as “AESn,” i.e., no space or hyphen, e.g., AES3 not: AES 3 or AES-3.
  • Information documents are represented as “AES-nid,” with hyphen & suffix “id,” e.g., AES-6id.
  • Project Reports are represented as “AES-Rn,” with hyphen, e.g., AES-R2.
  • Technical Documents are represented as “AESTDnnnn.n.nn-yy,” e.g., AESTD1001.0.01-05.

AES/EBU Obsolete terminology; the correct terminology is now AES3.

affect vs. effect The technical answer is that affect is a verb and effect is a noun. The commonly seen example is: the affect of the effect is such and such. In pro audio an effects box affects the sound. The box is a thing, a noun, while the result modifies (a verb) the sound.

aka abbreviation for also known as. Omit the periods: not: a.k.a.

all-pass is hyphenated.

alternating current Abbr. ac Officially the IEEE dictionary is very clear that the abbreviation for alternating current is “ac” not “AC.” However most everyone agrees (mags, technical journalists, me, etc.) that when abbreviating alternating current in a standalone sense, that it looks better and reads clearer if you use uppercase, e.g., “The device runs off AC voltage,” instead of “The device runs off ac voltage,”, particularly if the abbreviation begins or ends a sentence. Imagine a sentence like this: “Ac is a type of generator voltage.” Or, “Do you want ac or dc?” Both work better with uppercase. As for Vac vs. VAC, both are seen and accepted even though Vac is the IEEE standard.

A.M. See: ante meridiem

ambience vs. ambiance Use ambience to mean the surrounding sound field and ambiance to mean the atmosphere or mood created by a particular environment.

ampere Abbr. A

amplitude modulation Abbr. AM All caps; no periods.

ante meridiem Abbr. a.m. or A.M. Both with two periods. Usage Note: By definition, 12 A.M. denotes midnight, and 12 P.M. denotes noon, but there is sufficient confusion over these uses to make it advisable to use 12 noon and 12 midnight where clarity is required.

apostrophes Use to indicate missing letters and numbers (for example, isn’t for is not, or ‘60s for 1960s but not 1960’s (unless it is possessive). Another main usage is to make a word possessive, e.g., Joe’s. Note that most plurals add a simple "s" not "‘s". Correct: DJs not: DJ’s unless it is possessive rather than plural. [And of course there are the everyday exceptions to this possession rule: his, its, whose, their, hers, ours, yours, and theirs, all indicate possession but do NOT get apostrophes.]

atmosphere, standard (as in one standard atmosphere) Abbr. atm (no period)

back up or backup Back up is a verb meaning “to duplicate for storage purposes” i.e., to back up your hard drive. Backup is a noun or adjective referring to what you have created, i.e., the backup or the backup tape.

band-limiting is hyphenated.

bandpass, bandreject and bandstop are all one word.

bandwidth Abbr. BW is one word and the abbreviation is always caps.

baud is not capitalized; it is a unit (one bit per second) and treated just like every other unit.

beamwidth is one word.

bel Abbr. B

biamp is one word.

bibliography style Many styles exist for technical bibliographies, references and footnotes. What follows are the ones used by the Audio Engineering Society and are recommended:


Books: Author(s) [Last name, First initial], Title [in italics], Ed. (Publisher, ISBN, Location, Year).
Example: Beranek, L., Riding the Waves (The MIT Press, ISBN 978-0-262-02629-1, Cambridge, MA, 2008).

Periodicals: Author(s) [Last name, First initial], “Title of article,” [in quotation marks], Periodical Title [in italics], vol., pp., (year month).
Example: Linkwitz, S., “Active Crossover Networks for Non-coincident Drivers,” J. Audio Eng. Soc., vol. 24, pp. 2-8 (1976 Jan/Feb).

Convention Papers: Author(s) [Last name, First initial], “Title of paper,” [in quotation marks], presented at the [number] Convention of the Audio Engineering Society, J. Audio Eng. Soc. (Abstracts), vol., pp., (year month).
Example: Klippel, W., “Speaker Auralization – Subjective Evaluation of Nonlinear Distortion,” presented at the 110th Convention of the Audio Engineering Society, J. Audio Eng. Soc. (Abstracts), vol. 49, pp. 526-527 (2001 June), convention paper 5310.

billion Use this term sparingly and clearly explain it since a “billion” in the USA equals 109 but in popular Great Britain usage it equals 1012, although now the US meaning is being seen more often, which further confuses things. [All higher terms, e.g., trillion, quadrillion, etc., traditionally equal vastly greater sums than their USA meanings, but it is changing so be careful.]

bit or bits spell out; do not abbreviate, and add a hyphen if used as an adjective: 24-bit converter.

binary digits Use “logic 1” and “logic 0” to describe, not just “1” or “0.”

brackets [ ] are around a referenced source publication. [Chicago Manual of Style], [AHD], [IEEE], etc. Not used when quoting a single person or author. Brackets are also used for parentheses within parentheses and to enclose the phonetic transcription of a word.

Bundle The shortened form for CobraNet Bundle; always with a capital B to differentiate it from a bundle of wires.

bus vs. buss It is bus; never buss. Bus means electrical conductors used for transmitting signals or power from one or more sources to one or more destinations. Buss means to kiss. Preferred plural is buses.

bytes Spell out; do not abbreviate.

cancelling vs. canceling; also canceller vs. canceler While both are correct, two ls are seen most often in pro audio use.

capitalization in title case headlines, capitalize all nouns, pronouns and verbs, and all words of four or more letters. Capitalize both parts of a hyphenated word: Constant-Q, etc.

Category wiring with a capital C and lowercase w.

CAT 5 or Cat 5 cable, either all caps or title case with a space not a dash.

CAT 5e or Cat 5e enhanced cable, either all caps or title case with space and lowercase e.

cathode Abbr. ka

cf. Abbr. Latin confer (compare) with a period.

Celsius Abbr. C Always capitalized, this is one of those exceptions to the rule of using lowercase when a unit is spelled out if derived from a person’s name, in this case Anders Celsius. The term “Celsius” is preferred to “centigrade” in technical contexts.

centigrade Do not use in technical writing; use Celsius instead.

chapter Abbr. Chap. with a period.

coaxial is one word.

CobraNet® A registered trademark of Cirrus Logic, always cap C and N with registration mark and affiliation stated once per document. The registration mark is not necessary when used as a logo.

commas in numbers See: SIRules below.

complement vs. compliment Different words, different meanings: complement means to complete something, while compliment means to praise something.

compound words A combination of two or more independent words, such as loudspeaker, graphic equalizer, or high-cut. They are written one of three ways: as separated words, hyphenated words or as one word. Traditionally in the English language a compound noun begins life as two separate words then over time becomes hyphenated and finally after long enough usage it becomes one word. A recent example is the progression of the compound “Web site” to web-site to website in a very short time. A compound adjective is most often hyphenated, while compound verbs are generally written as two words. However there are so many exceptions and variations that simple rules do not apply. The best approach is to look it up in the dictionary and hope it is there.

constant-Q is to have a hyphen and a capital Q.

converter as opposed to “convertor” for pro audio use even though both are technically correct.

copyright Copyright law in the United States says that anything originally written or created is automatically protected. The American Heritage Dictionary explains that it is the legal right granted to an author, composer, playwright, publisher, or distributor to exclusive publication, production, sale, or distribution of a literary, musical, dramatic, or artistic work. The copyright symbol © is not required to appear, however it is good practice to do so once in each document. This should appear on the first page formatted as follows: copyright symbol year company or individual name. Example: © 2009 Rane Corporation. It is also a good idea to add “All Rights Reserved,” however it is not required. For an excellent reference about the many details involved see Reference 3, pp. 21-35.

couldn’t care less versus could care less The correct phrase is “couldn’t care less,” that is, you could not care less about this issue; it is completely unimportant to you; not worth a single thought. Whereas the phrase “could care less,” means that you really could care less than you do, that you do care somewhat about this issue, that it has some importance to you, but that is exactly the opposite context that this phrase is used. Actually I couldn’t care less if you use “could care less,” because it only makes you look foolish.

counterclockwise is one word.

crossfader is one word.

crosspoint is one word.

cubic centimeter Abbr. cm³ not: cc

current Abbr. I

cutoff is one word.

cut-only is hyphenated.

daisy-chain is hyphenated.

dashes Three common types:


hyphen Use for joining compound words, e.g., low-pass, to divide a word up at the end of a line (never a recommended practice) or as a minus sign. [Technically, to old-school typesetters, the minus sign differs from a hyphen in order to match the horizontal line in the plus symbol, but their interchangeability is so common that it is our standard.] See: hyphens for more detail on multiple hyphen use.

em dash Use to indicate a break or interruption in thought, or to separate a sentence from a bullet point. Note that the em dash has no space on either side, e.g., The Rane website—a great place for pro audio information—is easily found at The em dash is not visible on keyboard and must be activated. The shortcut is Alt-Ctrl-Num -, i.e., press Alt and Ctrl and the dash button on the keypad. Note that this only works for keyboards with keypads, which rules out laptops. For those, you must use Insert Symbol or Character Map. [The name comes from its being the width of an ‘m’ in printing.]

en dash Use as a substitute for the word ‘to’ when adding dates, or other ranges. Note also that the en dash also has no space on either side e.g., November 24–30, 2011. Like the em dash the en dash is not visible on the keyboard and must be activated. The shortcut is Ctrl-Num -, i.e., press Ctrl and then the dash button on the keypad. Note that this only works for keyboards with keypads, which rules out laptops. For those, you must use Insert Symbol or Character Map. [The name comes from its being the width of an ‘n’ in printing.]


  • Always spell out the month or use the 3-letter abbreviation so there is no confusion as to which digit is the month and which digit is the day. Since all three styles are seen in pro audio use: month-day-year (US style); year-month-day (ISO 8601, scientific standard) and day-month-year (European style) it is clearest to spell out the month.
  • Do not truncate the year to two digits, again for clarity; however exceptions to this often occur when computer fields are restricted to two digits.
  • When using only the month and year do not use a comma between them, e.g., January 2008 or Jan 2008. Only use a comma to separate the numerical day and year, e.g., January 17, 1948.
  • When using only the month and day never use the suffixes -st, -nd, -rd or -th behind the numerals (which makes them ordinal dates as opposed to cardinal dates). Correct: Jan 17 never Jan 17th. The suffix is understood and read that way but not written out. Use only when the month is omitted and the number stands alone and is preceded by the,as in: The install is scheduled for the 17th.


[Historical Note: These ordinal abbreviations are actually hybrid contractions: 1st is “1” + “st” from “first”. Similarly, we use “nd” for “second” and “rd” for “third” and “th” for “fourth”.]

days of the week Always capitalize and (recommended) spell out, but if you must abbreviate then use three letter abbreviations: Sun, Mon, Tue, Wed, Thu, Fri, and Sat without periods, although there is no universal agreement on this. The four letter abbreviation, Tues, and five letter abbreviation, Thurs, are still very common. And increasingly popular are the newer shorter abbreviations: Su, M, Tu, W, Th, F and Sa, without periods, particularly for table use.

dB Abbreviation for decibel, meaning one-tenth of a Bel, after Alexander Graham Bell. Decibels have no units. Everything is relative. Since it is relative, then it must be relative to some 0 dB reference point. To distinguish between reference points a suffix letter is added as follows [The officially correct way per AES-R2, IEC 60027-3 & IEC 60268-2 documents is to enclose the reference value in parenthesis separated by a space from “dB”; however this never caught on, but is shown below.]:

dBA Unofficial but popular way of stating loudness measurements made using an A-weighting curve; cap B and A, no dash or space. If response time is included add –Fast or –Slow, e.g., 92 dBA-Fast.

dBC Unofficial but popular way of stating loudness measurements made using a C-weighting curve; cap B and C, no dash or space. If response time is included add –Fast or –Slow, e.g., 92 dBC-Fast.

dBf Preferred informal abbreviation of the official dB (fW); cap B and lowercase f.

dBFS Preferred informal abbreviation for the official dB FS (with a space); cap B, no space and cap FS.

dBm Preferred informal abbreviation of the official dB (mW); cap B and lowercase m.

dBr An arbitrary reference level (r = re; or reference); cap B and lowercase r.

dB-SPL Preferred abbreviation for sound pressure level (actually sound intensity); cap B with dash followed by cap SPL.

dBu Preferred informal abbreviation for the official dB (0.775 V); cap B and lowercase u.

dBV Preferred informal abbreviation for the official dB (1.0 V); cap B and uppercase V.

decimal numbers See: numbers with decimals

degree temperature symbol The degree mark is always placed next to the unit, as in 49 °F or 12 °C; it is never placed next to the number.

degree angle symbol The degree mark (as well as minute and second marks) is always placed next to the number with no space: 6º north, 36º46´N, etc.

delta-sigma vs. sigma-delta Either term is acceptable; both are seen and understood equally.

deselect vs. unselect Use deselect; as in: to decide not to select. This can be argued both ways but the consensus is to use "deselect."

diffuser or diffusor Both are correct, however the British spelling, diffusor, is seen most often in pro audio use.

direct current Abbr. dc The IEEE dictionary is very clear that the abbreviation for direct current is “dc” not “DC.” However most everyone agrees (mags, technical journalists, me, etc.) that when abbreviating direct current in a standalone sense, that it looks better and reads clearer if you use uppercase, e.g., “The device runs off DC voltage,” instead of “The device runs off dc voltage,”, particularly if the abbreviation begins or ends a sentence. Imagine a sentence like this: “Dc is a type of generator voltage.” Or, “Do you want ac or dc?” Both work better with uppercase. As for Vdc vs. VDC, both are seen and accepted even though Vdc is the IEEE standard.

direct-radiator is hyphenated.

disc vs. disk A disc is a vinyl or optical storage medium, like a DVD or compact disc. A disk is a magnetic storage medium, like a floppy disk, hard disk or zip disk.

discrete vs. discreet For pro audio use it is most oftendiscrete,” since it means a separate thing, while “discreet” means showing prudence and self-restraint. (You may want to be discreet when bussing someone.)

DJ (disc jockey) is always capitalized; never lowercase dj.

DJing without hyphen.

DJs without apostrophe.

driver is often the shortened form for “loudspeaker driver” but it should not be used. It can be confusing. The preferred usage is to spell it out as “loudspeaker driver” for clarity.

DSP (digital signal processor) is always capitalized, never lowercase dsp.

east Abbr. E

echo canceller or echo cancelling are not hyphenated and are spelled with two ls.

edition Abbr. ed.

effect See: affect vs. effect.

e.g. Abbr. Latin exempli gratia (for example).

ellipsis Three dots with a space before and after, like this "... " (no spaces between dots). Treat it as a three-letter word used two ways: 1) Indicating omission; 2) Indicating pause or a sudden break in though (much like an em dash).

email is one word and lowercase (not E-mail or Email). See usage note at “website.”

em dash See: dashes.

en dash See: dashes.

end-user is hyphenated.

EQ Abbreviation for equalizer. All caps (never: eq).

EQ'd with apostrophe.

EQing without hyphen.

equation Abbr. Eq.

et al. Abbr. Latin et alii (and others) Note that there is no period for “et” but there is for “al.”

etc. Abbr. Latin etcetera (the rest). Always use only once, never multiple times like “etc., etc.” Use sparingly. The normal meaning is “This list is longer but I don’t want to include the other items” but for many writers they use it to mean: “If I could think of more items I’d make this list longer.”

Ethernet with a cap E.

Euroblock is in title case, not euroblock or EuroBlock.

Fahrenheit Abbr. F Always capitalized, this is another of the exceptions to the rule of using lowercase when a unit is spelled out if derived from a person’s name, in this case Gabriel Daniel Fahrenheit.

farad Abbr. F

far-end with a hyphen.

far-field with a hyphen.

feet Abbr. ft

feet / meters one space before and after the slash mark.

fewer vs. less “fewer” refers to a number; “less” refers to quantity. For example, Rane has fewer than 1,000 employees, and five is less than ten.

figure Abbr. Fig.

figure-eight is lowercase with hyphen but no of.

figures Abbr. Figs.

frequency modulation Abbr. FM All caps; no periods.

follow up vs. follow-up Similar to 16-bit, but here is a simple trick suggested by business writing expert, Lynn Gaertner-Johnston:

If you can use the word the directly in front of the words follow up, they need a hyphen. Examples:

Please give Assan the follow-up test.
Have you sent the follow-up to Marty?
Make a follow-up call tomorrow. [You could replace a with the.]

In contrast, the sentences below would not work with the word the inserted before follow up:

Please follow up with Assan by giving him the test.
Did you follow up with Marty?
Follow up by phone tomorrow.


foot Abbr. ft

footswitch is one word but foot pedal is two words.

frequency response For clarity, state the units for each number when giving a range. Example: 20 Hz to 20 kHz not: 20–20 kHz. The word “to” is preferred over the en dash (the long hyphen symbol).

full-range is hyphenated.

gain-sharing vs. gain sharing See: 16-bit.

gauge vs. gage Use 'gauge' for wire diameter reference; use 'gage' when referring to a pledge or challenge.

gauss Abbr. Gs

gigahertz Abbr. GHz

gram Abbr. g

grille vs. grill It is grille, as in a loudspeaker grille, as opposed to a barbecue grill.

half-normalled is hyphenated.

hard copy is two words; not one word and not hyphenated – someday but not yet.

heat sink is two words; just like above: not one word and not hyphenated - someday but not yet.

henry Abbr. H

hertz Abbr. Hz. Always a space between the number and Hz.

high-cut is hyphenated.

high-pass is hyphenated.

home run is two words (don't ask!)

hour Abbr. h

hyphens and compound adjectives

  • Use hyphens to distinguish between the modifier and the noun: high-speed network, light-emitting diode, kilowatt-hour meter, etc. – unless the compound modifier is an adverb ending in ly: widely dispersed audio, highly distorted response, etc.
  • Use double hyphens for triple compounds: cut-and-paste editing, drag-and-drop configuration, ultra-high-density chips, etc.
  • Use hyphens when an adverb combines with a participle to act as an adjective: well-known problem, much-despised coding, interrupt-driven process, etc. – except when the adverb-participle combination follows a linking verb or form of “to be,” the compound is then technically acting as a verb, not as an adjective, and so should not be hyphenated: The consultant is well respected in the industry. Also see: dashes.

hyphens and numbers

  • Use a hyphen for the written-out compound numerals twenty-one to ninety-nine: thirty-five, forty-two, sixty-five, etc.
  • Use a hyphen for written-out fractions: one-third, one-fourth, etc.
  • Use a hyphen when a number is followed by a unit of measurement and the resulting compound is used as an adjective: 16-bit word, 48-kHz sample rate, 12-inch disc, etc.
  • Omit a hyphen when using a number + percentage: 50 percent, 15 percent, etc.
  • Use a hyphen when the words precede a noun, e.g., It is a 24-bit converter. But omit it when the words follow the noun: The converter uses 24 bits.
  • Use a hyphen for age terms: 15-year-old sound system, 20-year-old operators, etc.
  • Use a hyphen rather than repeat the second part of a modifier: The signal processor could be configured for two-, three- or four-way loudspeaker systems.

i.e. Abbr. Latin id est (that is) with two periods as shown, and when used in a sentence it goes between two commas, i.e., like this.

inch Abbr. in

incoherent vs. noncoherent Incoherent means 1. Lacking cohesion, connection, or harmony; not coherent: incoherent fragments of a story. 2. Unable to think or express one's thoughts in a clear or orderly manner: incoherent with grief. [AHD] No formal definition exists for noncoherent; however, it is seen commonly in technical literature meaning lacking connection or harmony, e.g., laser, radar and communication fields refer to noncoherent light and transmissions; although the data acquisition field refers to incoherent sampling. Therefore for most things use incoherent, but recognize that there are exceptions for specialized technologies.

in-ear monitors with a hyphen.

instrument-level is hyphenated.

Internet is in title case, and refers to the world-wide network of applications such as email and websites. It may also be referred to as the Net, also in title case. Both are referred to as the Net or the Internet, referring to the global aspect of one interconnected system.

its versus it's The possessive form is its, without an apostrophe, while it's is the contraction of it is or it has, always with an apostrophe.

italics Titles of books, films, music, articles etc. A chapter or article from a journal or magazine will have the chapter or article in “quotes” and the journal or magazine title in italics.

joule Abbr. J

joystick is one word.

k A lowercase k denotes 1000 times.

K An uppercase K denotes 1024 bits or 210 bits. Popularly used when referring to computer file and memory sizes, however it is technically incorrect. As of 1998, with the approval of Amendment 2 to IEC 60027-2, the correct abbreviation for 210 is Ki. See table below under SI. It is noted that over ten years later the technical community has yet to embrace the correct binary prefixes. There is a lesson here about the power of momentum and precedence.

kelvin Abbr. K Due to the possible confusion with the above definition for uppercase K, it is always better to spell out kelvin rather than use the abbreviation.

kilobit Preferred is to spell out for clarity but if you must then abbr. kb (lowercase k and b). A term signifying one thousand bits. Also kb/s or kbps for kilobits per second.

Kilobit Preferred is to spell out for clarity but if you must then abbr. Kb (uppercase K and lowercase b). A term signifying 1024 bits, but should use Kibibit. Also Kb/s or Kbps for Kilobits per second or Kibibits per second.

kilobyte Preferred is to spell out for clarity but if you must then abbr. kB (lowercase k, uppercase B). A term signifying one thousand bytes. Also kB/s or kBps for kilobytes per second.

Kilobyte Preferred is to spell out for clarity but if you must then abbr. KB (uppercase k and B). A popular term signifying 1024 bytes, but should use Kibibyte. Also KB/s or KBps for kilobytes per second or Kibibytes per second.

kilometers Abbr. km

kilohertz Abbr. kHz When used as a range, use 20 Hz to 20 kHz, not: 20 to 20kHz

kilohm Abbr. or kohm [Note: use one "o" not kiloohm or kilo-ohm.]

laptop is one word.

lay, lie

  • Lay means put down, or place. And it requires a direct object, the thing that is put or placed. Electricians lay cable. In other tenses, lay takes these forms: Electricians laid cable yesterday; Electricians are laying cable faster than ever; Electricians had laid cable before yesterday. The lay length of the cable is 0.5 in.
  • Lie means recline, or occupy a location. It does not take an object because the subject can accomplish those things alone. The unused cable lies on the bench. And in other tenses, lie takes these forms: The unused cables are lying on the bench despite being needed elsewhere; The unused cables had lain on the bench before being installed. [Paraphrased from The New York Times Manual of Style and Usage.]

leveler vs. leveller While both are correct "leveler" is preferred in pro audio use.

line-level is hyphenated.

liter Abbr. L

loudspeaker Always spell it out; do not abbreviate it as “speaker,” which can be confusing.

low-cut is hyphenated.

low-pass is hyphenated.

lowercase is one word.

Mac® Abbreviation for Macintosh computer, a registered brand name of Apple®. Always in title case with the registration mark appearing once per document. Never: MAC.

mappable with two "p"s.

megahertz Abbr. MHz

meter Abbr. m

meter per second Abbr. m/s not: mps

meters / feet one space before and after the slash mark.

mic-level is hyphenated when referring to an input.

microfarad Abbr. µF with the symbol for the Greek letter mu; never lowercase u.

micrometer Abbr. µm

microhm Abbr. µΩ or µohm [Note: use one "o" not microohm or micro-ohm.]

microphone Abbr. mic (never: “mike”); however the abbreviation for the verb is miking (never: “mic’ing”). [One of the many inconsistencies of pro audio jargon.]

microsecond Abbr. µs

microvolt Abbr. µV

MIDI is all caps.

midrange is one word. [Another pro audio inconsistency since full-range requires a dash.]

milliampere Abbr. mA

millihenry Abbr. mH

millimeter Abbr. mm

millisecond Abbr. ms not: msec, mSec, or millisec.

millivolt Abbr. mV

minute (time) Abbr. min (no period)

minute (angle) Symbol ΄

monoed Yes, it is a word; yes, it is correct. It is the verb form for mono – one of many pro audio inspired jargon terms.

months of the year Always capitalize and either spell out (recommended) or use the three letter abbreviations without periods: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, and Dec.

moving-coil and moving-magnet are hyphenated.

MP3 the abbreviation for MPEG-1, Layer 3 is in all caps with no space or hyphen.

MPEG-2 or MPEG-4 all caps with hyphen.

multi Most all "multi" words are one word without a hyphen. The Journal of Audio Engineering even used "multimicrophone." Here are some other examples:

  • multiamplifier
  • multiband
  • multichannel
  • multiclient
  • multimedia
  • multimode
  • multiprocessor
  • multitrack
  • multizone

Musikmesse is one word and "messe"is not capitalized.

nanosecond Abbr. ns

narrative mode encompasses who tells the story, and how the story is told. A well-written article stays consistent within itself in regards to point of view, time, and active or passive voice. (ref)


Narrative: point of view describes the author's position in relation to the story being told. A story can combine First- and Third-person if it is about yourself and someone else.

  • First-person view is told by the narrator about him/herself. Pronouns include “I” or “we.” First-person would be applicable to “My DJ Set with the London Symphony.”
  • Second-person view is when the narrator refers to the reader as “you,” to relay a personal interaction. Though “you” can be implied, it is more personal to say “you.” This is the preferred view when writing friendly instructions at Rane. “Your First Party with Serato DJ.”
  • Third-person view is about “he,” “she,” “they,” “it.” Use this if the narrator isn’t present, and the story is about someone else. “Z-Trip’s Performance at the Grammy's.”


Narrative: time determines past, present or future. Present tense is best for instruction. Avoid “should,” this is uncertain future tense, and only for if/then situations if both are explained. Instead, write about what will happen, and if it doesn't, do this.

  • Past tense occurred before the current time. “He put the needle on the record.”
  • Present tense occurs now, and for instruction, do this now. “Put the needle on the record.”
  • Future tense is when you can predict an outcome. “When you put the needle on the record.”

Narrative: active vs. passive voice.

  • Passive voice: “Rane has hired a new director” is passive voice and dull as dirt.
  • Active voice: “Rane hires a new director” is active voice and more interesting. Try to follow the active voice rule: “Noun, Verb.” “DJ Rane rocked the Palace,” rather than “The Palace was rocked by DJ Rane.”


nauseous vs. nauseated. Nauseous means something is sickening; nauseated means you feel bad.


near-end with a hyphen.

near-field with a hyphen.

neper Abbr. Np

nominal This word has several definitions but the one of importance to pro audio is its engineering sense meaning insignificantly small; trifling: a nominal amount. It does NOT mean average or typical as is so often seen. When specifying impedance it usually means “named.” The nominal impedance is 8 ohms.

non-circular is hyphenated.

non-linearity is hyphenated.

normalling with two ls.

north Abbr. N

numbers Write out numbers less than 10 when they mean quantity only, as in five people, but use numerals when the number has units, e.g., it is 7 W, not seven W.

numbers with decimals Use a zero before the decimal point for numbers less than one (correct: 0.54 not: .54).

oersted Abbr. Oe

off-axis is hyphenated.

offline is one word.

ohm Abbr. Ω (uppercase omega, the last letter of the Greek alphabet)

on-axis is hyphenated.

one-third octave or 1/3-octave Either is correct, but it is not “third-octave” – see third-octave.

online is one word.

opamp or op amp: take your pick.

ounce Abbr. oz without a period.

overvoltage and undervoltage are one word.

palmtop is one word.

pascal Abbr. Pa

passband is one word.

patchbay is one word; not two words and not hyphenated.

per Represent by a virgule, which is a diagonal line “/” used to separate alternatives. For example km/h is kilometers per hour.

percent Symbol % One word with no space between the number and symbol: 15%, 25%, etc. However a space is added before the spelled-out form: 20 percent, 98 percent, etc.

periods Do not type two spaces after a period when using a computer. This rule was developed in high-school typing classes for use on typewriters, which use a mono-spaced courier font, meaning all characters take the same amount of horizontal space. Computer fonts are designed so the letters fit together for better readability and automatic spacing is built-in after the period.

phaser with an "e" is the electronic device creating an effect similar to flanging,

phasor with an "o" is the mathematical name for a complex number expressing the magnitude and phase of a time-varying quantity. It is also the correct spelling for the favorite Star Fleet weapon.

picofarad Abbr. pF

plug-in is hyphenated; not two words; not one word.

P.M. See: post meridiem below.

post meridiem Abbr. p.m. or P.M. Both with two periods. Usage Note: By definition, 12 A.M. denotes midnight, and 12 P.M. denotes noon, but there is sufficient confusion over these uses to make it advisable to use 12 noon and 12 midnight where clarity is required.

ppm Abbr. for parts per million The SI rule is to not use “ppm,” and to use “quantity x 10-6” instead. Correct: The oscillator drift rate is 2 x 10-6 not: The oscillator drift rate is 2 ppm. However, the use of ppm is seen so often and is always clear as to its meaning that it is commonly found in pro audio literature. [Although it is interesting to note that the SI rules allow for the use of % (percent), which is the same sort of dimensionless quantity meaning parts per hundred.]

printout is one word.

pseudorandom is one word.

punctuation best practices, according to The Oatmeal.

  • Use a semicolon to connect two independent clauses.
  • Use an apostrophe to indicate possession, or a two-word contraction, with exceptions.

quotation marks and punctuation: inside or outside? Inside is the U.S. standard; outside is the U.K. standard. Colons and semicolons are the exception. For example, the correct spelling is "bass," and "treble."

rack-mount is hyphenated.

rack unit See: U

Rane is always written in title case even though the logo is all caps.

ratios No space on either side of the colon indicating a ratio (correct: 2:1 not: 2 : 1)

RCA (phono jack) is all caps.

real time Two words. It is hyphenated when used as an adjective, such as real-time teleconferencing.

recycle is one word; no hyphen.

redundancies The pro audio world is full of accepted redundancies that derive mostly from digital technology. The rule is violated so often that these terms have become mainstream: PIN number, DOS operating system, ISP provider, LCD display, RAM memory, RISC computer, TCP/IP protocol, DSP processor, etc. Nevertheless they are redundant and you should look out for them and reword your sentence to remove them.

references See: bibliography style

regardless vs. irregardless It is regardless as there is no such word as irregardless. Here is what the American Heritage Dictionary says about its origin: "Irregardless is a word that many mistakenly believe to be correct usage in formal style, when in fact it is used chiefly in nonstandard speech or casual writing. Coined in the United States in the early 20th century, it has met with a blizzard of condemnation for being an improper yoking of irrespective and regardless and for the logical absurdity of combining the negative ir- prefix and -less suffix in a single term. Although one might reasonably argue that it is no different from words with redundant affixes like debone and unravel, it has been considered a blunder for decades and will probably continue to be so."

registered trademark rules See: trademark.

reinstall is one word; no hyphen.

resistance Abbr. R

RJ (Registered Jacks) As in RJ-11 or RJ-45 modular telephone jacks; always capitalized with a dash.

RJ-45 vs. 8P8C Technically 8P8C (8 position 8 contact) is the connector while RJ-45 is one wiring method that uses an 8P8C connector; however it is not the wiring configuration for Ethernet, which is where this connector is most often used in pro audio. But due to overwhelming use of the term “RJ-45” to mean an Ethernet cable (either cross-over or straight-through) it is the accepted use in pro audio since there is no confusion even though technically it is incorrect. Got that? It is simply the easiest solution since using the term “8P8C” generally elicits questions while using “RJ-45” is always understood to mean Ethernet cabling. (Another inconsistency.)

rms is lowercase; stands for root mean square, as in Vrms = 40 V. Not: uppercase RMS, unless it is the first thing in the sentence.

rolloff is one word.

RPM is uppercase and is the abbreviation for revolutions per minute.

RS (Recommended Standard) As in RS-232, RS-485 and others, always capitalized with a dash.

RU See: U

RX Abbreviation for receive or receiver; both letters uppercase.

Scratch Live is written in title case.

seasons of the year Always lowercase (winter, spring, summer and fall) unless beginning a sentence.

second (time) Abbr. s not: sec or Sec

second (angle) Symbol "

setup is one word (not set-up or set up). See usage note at “website.”

SI The International System of Units universally abbreviated SI (from the French Le Système International d’Unités) and is always capitalized.

SI Prefixes for Decimal Numbers



































































SI Prefixes for Binary Numbers









kilobinary: (210)1

kilo: (103)1




megabinary: (210)2

mega: (103)2




gigabinary: (210)3

giga: (103)3




terabinary: (210)4

tera: (103)4




petabinary: (210)5

peta: (103)5




exabinary: (210)6

exa: (103)6

SI Rules and Abbreviations The goal is to make quantity values as independent from language as possible. The most common rules and abbreviation follow:

Numbers combined with units are never spelled out. They are always written as Arabic numbers not words. And units are always abbreviated, never spelled out. Examples:
5 V not: five V
40 W not: 40 watts
The current was 12 A. Not: the current was 12 amps. Not: the current was twelve amperes.

Unit names when written out are never capitalized:
watts not: Watts
amperes not: Amperes
volts not: Volts

Unit symbols or abbreviations are always capitalized when derived from a person’s name: ampere is A, farad is F, but second is s and meter is m. But, as always, there are exceptions. Example:
liter is L (to avoid confusion between lowercase l and the number 1)

For clarity, state the units for each number when giving a range. Example:
20 Hz to 20 kHz not: 20–20 kHz

The word “to” is preferred over the en dash (the shorter hyphen symbol). Example:
10 MHz to 100 MHz not: 10–100 MHz

Common exceptions are when stating periods of time. Examples:

Always space the unit symbol from the number. Examples:
35 mA not: 35mA
25 °C not: 25° C
11 kΩ not: 11k Ω
4 kHz not: 4k Hz

One exception is when using the degree mark to indicate an angle: a 30° chamfer or an opening of 45°; another is when a number and percent are used: 15%, 45%, etc.

Unit symbols are never pluralized. Examples:
80 W not: 80 Ws
15 cm long not: 15 cms long

Unit symbols are not followed by a period unless at the end of a sentence. Examples:
The power supply is 15 V.” or “It requires a 15 V power supply.” But not: “It requires a 15 V. power supply.”

SI Rules and Abbreviations: Pro Audio Exceptions

Unit symbols are never modified. This rule says do not use such terms as 10 Vrms or 20 Vpk or 15 Vmax, Vmin, etc. as unit symbols. Instead use Vpk = 20 V or Vrms = 10 V or Vmax = 15 V. [This is an example of where the pro audio industry deviates from the rule. While technically incorrect, terms such as Vrms or Vmax as unit symbols are unambiguous and seen everywhere and accepted; however following the rule is better.]

Spacing numbers: the rule says to use thin spaces (which most word processors do not provide) instead of commas or periods to group digits in threes to the left and right of the decimal point for numbers greater than four digits. For example the rule says write it this way: 1 234 567 not: 1,234,567 or as many Europeans do: 1.234.567. The idea is to eliminate confusion between using commas or periods. [This convention is rarely followed in pro audio.] Four digit numbers do not use a space or comma or period, e.g., The power output was 1250 W or The venue holds 2500 people.

siemens Abbr. S

sigma-delta vs. delta-sigma Either term is acceptable; both are seen and understood equally.

signal-to-noise ratio with hyphens. Abbreviate as S/N or SNR; both are seen and accepted, however S/N is the most common.

singlemode is one word; no hyphen.

soundcheck is one word; no hyphen.

sound pressure level Abbr. SPL No hyphens and abbreviation is always capitalized – never: spl.

south Abbr. S

spacing rule Nearly always space the symbol from the number. For example, 8 W, 15 cm, 8 Ω and 60 A are all correct. Notable exceptions are the degree (angle) mark (as well as minutes and seconds of angle) and the percent symbol.

S/PDIF is all caps with slash and no spaces.

speaker is usually the shortened form for “loudspeaker” but it should not be used. It can be confusing. The preferred usage is to spell it out as “loudspeaker,” or if referring to a person then use “talker” or “presenter” or something similar.

Speakon® A registered trademark of Neutrik® for their original design loudspeaker connector. Always with a cap S and include the registration mark and acknowledgement once per document.

specifications that include numbers are to have a space between the number and the unit symbol (abbreviation), such as 20 Hz, 300 W, and 98 dB. Where “k” (or kilo) denotes a thousand, it is included with the symbol, as in 20 kHz, or 20 kΩ. Uppercase K denotes 1024 bits and is used when referring to computer file and memory sizes. Do not abbreviate a unit of measurement unless it is used in conjunction with a number. When used as a range, use 20 Hz to 20 kHz.

SPL (sound pressure level) is always capitalized – never: spl.

square meter Abbr.

stopband is one word.

straightforward is one word.

subframe is one word.

subsonic is one word.

subwoofer is one word.

talker preferred term instead of “speaker,” which can be confused with “loudspeaker.”

teardown is one word.

temperature symbol See: degree temperature symbol

tesla Abbr. T

their, they’re, and there. "there” indicates location; “their” indicates possession; and “they’re” is the contraction of “they are.”

third-octave Term referring to frequencies spaced every three octaves apart. For example, the third-octave above 1 kHz is 8 kHz. Commonly misused to mean one-third octave. While it can be argued that “third” can also mean one of three equal parts, and as such might be used to correctly describe one part of an octave split into three equal parts, it is potentially too confusing. The preferred term is one-third octave or 1/3-octave.

time code or timecode Both are seen and acceptable with the two-word version seen more often.

time delay vs. signal delay There is no such thing as time delay. It is a a misnomer. You cannot delay time Misused to mean signal delay.

tip-ring-sleeve See: 1/4" TRS.

Title Case or title case is writing a word with its first letter in uppercase and the remaining letters in lowercase.

trademark ™ and registered trademark ® rules: The ™ and ® marks only need to appear the first time that the trademark is used in any document. If the trademark is registered then at the page bottom or at the end of the document, place the italicized phrase: Xxyyzz is a registered trademark of Company Name Corporation.

triamp is one word.

TX Abbreviation for transmit or transmitter; both letters uppercase.

U Always uppercase, U is the abbreviation for the “modular unit” on which rack panel heights are based. Per the EIA and ANSI standard ANSI/EIA-310-D-1992 Cabinets, Racks, Panels, and Associated Equipment, the modular unit is equal to 44.45 millimeters (1.75"). Panel heights are referred to as “nU” where n is equal to the number of modular units. Examples are 1U (1.75" high), 2U (3.5" high), 3U (5.25" high), etc. Popularly called rack units and often abbreviated “RU,” which is technically incorrect but not misleading.

underlines. Do not use. This is a style left over from typewriter or handwriting days. Computers have both bold and italic styles that are easier to read and more expressive. Use italics when describing a word or term for the first time, for words not normally used in English, titles of other books, movies, and other published works. Use bold when you need a word or phrase to stand out, as in headings, warnings, and software controls. The only acceptable use of underlines is in reference to a hyperlink in Internet applications.

unselect See: deselect.

USB 2.0 with a space between USB and any number.

uppercase is one word.

Vac vs. VAC, and Vdc vs. VDC Use either. Both are seen and accepted even though Vac & Vdc are the IEEE standards.

versus Abbr. vs. with a period.

Video-SL is always as shown.

volt or voltage Abbr. V Archaic abbreviation is E for electromotive force (since it is measured in volts) but the official SI abbreviation is V. Although E is still used in many equations.

volt-amps Abbr. VA Use hyphen when written out and all caps when abbreviated.

vs. Abbreviation for versus; always lowercase with a period.

watt Abbr. W

Web is in title case. Also see comments for Internet.

weber Abbr. Wb

website addresses are also known as URL, world wide web, www, or Internet addresses. They may be preceded with http://, but when the address begins with www or ends with .com or .net, the http:// is not necessary. For clarity, italicize web addresses when referring to them in a printed document, for example

website is one word. [Usage Note: The transition from World Wide Web site to Web site to website as a single uncapitalized word mirrors the development of other technological expressions which have tended to take unhyphenated forms as they become more familiar. Thus email is gaining ground over the forms E-mail and e-mail, especially in texts that are more technologically oriented. Similarly, there is an increasing preference for closed forms like homepage, online, and printout. From the American Heritage Dictionary, 4th Ed.]

west Abbr. W

Windows® is to have capital W. The ® mark only needs to appear the first time “Windows” is used in any document. At the page bottom or at the end of the document, place the italicized phrase: Windows is a registered trademark of Microsoft Corporation.

worst-case vs. worse-case It is "worst-case" even though it gets pronounced with a dropped "t."

XL and XLR connectors are all caps.

XLR vs. XL Technically only those connectors manufactured by Cannon can be correctly called “XLR” since the “R” refers to the rubber insulator between pins unique to the original Cannon female model and “XLR” was their registered copyright (now expired), however today Neutrik, Switchcraft and other manufactures of this model refer to it as an XLR connector so using the generic term “XL” only causes confusion.

XLR3 or XLR5 indicates 3-pin or 5-pin versions with no space or dash.

your vs. you're " Your" means possession; you're is the contraction of "you are."


1. Hale, Constance & Jesse Scanlon Wired Style: Principles of English Usage in the Digital Age (Broadway ISBN 978-0767903721, San Francisco, 1999). [A bit outdated but still a fine treatise on digital writing styles.]

2. IEEE 100: The Authoritative Dictionary of IEEE Standards Terms, Seventh Edition (IEEE ISBN 0-7381-2601-2, New York, 2000). [The answers for electrical & electronic terminology disputes.]

3. Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers (ISBN 978-0977966509, 2006). [Everything known about this subject and, I think, the best single source available.]

4. Taylor, Barry N., Ed., The International System of Units (SI) (National Institute of Standards and Technology NIST Special Publication 330, 2001 Edition.) [Available free here:]

5. Taylor, Barry N., Guide for the Use of the International System of Units (SI) (National Institute of Standards and Technology NIST Special Publication 811, 1995 Edition.) [This 86 page document is the definitive source of SI info. Download free here:]

6. The American Heritage Dictionary of the English Language, Fourth Edition (Houghton Mifflin ISBN 0-395-82517-2, Boston, 2000). [If you only own one dictionary make it this one.]

7. The Chicago Manual of Style, 15th Edition (The University of Chicago Press, ISBN 978-0-226-10403-4, Chicago, 2003). [The most famous style book of them all.]

8. Narrative Mode (Wikipedia) []


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