NAB

Abbreviation for the National Association of Broadcasters. NAB is the organization which establishes various standards for radio and television broadcasting, analogous to the BBC in England. Many NAB standards have trickled down to the pro and consumer audio industry as well, especially in the domain of tape recording.

Negative Feedback

If some of the output of an amplifier is made to be out of phase, and mixed back with the amp's input signal, it will partially cancel the input, reducing the gain of the amplifier; this is called negative feedback.

But, because it contains and therefore cancels any distortion introduced by the amplifier, negative feedback also has the effect of improving the linearity of the amplifier. Negative feedback can also lower output impedance, increasing damping factor, and can sometimes be made to flatten frequency response.

The key to negative feedback amplifiers is careful design. Too much phase shift and the amp will be unstable, and too much feedback will cause Transient Intermodulation Distortion.

Noise Floor

The noise floor of a device or system is the amount of noise generated by the device itself with no signal present, it is measured in decibels. All electronic devices will generate a certain amount of noise, even a piece of wire! Minimizing the noise floor leads to expanded dynamic range, and cleaner recordings or sound production.

Noise Shaping

All digital recording systems introduce quantization errors and noise. Noise shaping averages quantization errors, reducing them for low frequency sounds. This changes the timbre of the quantization noise, lowering low frequency content and emphasizing high frequency noise. A conventional filter can then be used to reduce the high frequency noise. The result to our ears is less perceived noise...

Non-Drop

Refers to Non-drop frame time code (see WFTD archive Time Code and Drop Frame Time Code): The method of time code computation where there are 30 numerical frames per second of video. In color NTSC (see WFTD NTSC) video there are actually only 29.97 frames of video per second. In a mathematical hour there would be 108,000 frames (30 frames per second x 60 seconds x 60 minutes). So, a mathematical hour of video is 108 frames longer than an hour of reality video.

Normal

Corresponding to the usual state, not out of the ordinary.
Something the inSync team is NOT accused of being (Can't figure that out; we don't think being nocturnal, doing strange things to guitars, lusting ferociously after electronic gear, and living in caves lit only by the blue phosphorescent glow of computer monitors is so strange. Besides, the resident sloths, bats and owls like it...)
In patchbays, a normal is an internal connection from the top row of jacks, to the bottom row. Normalling allows connections that are normally in effect to exist without the need for inserting a patch cable in the front of the bay. For example, the stereo outs of a mixer are generally connected to the inputs on a stereo mixdown deck. By connecting the mixer's outputs to the top back row of a normalled patchbay's jacks, and the mixdown deck to the bottom back row, a connection is made internally in the bay, and does not require extra patch cables.

Normalize

A DSP (Digital Signal Processing) function. Normalizing increases the gain of an audio file until its loudest point (or sample) is at maximum level. There are several benefits to this: First, the overall signal level is now higher, which makes subsequent gear in the audio chain perform better. Second, the signal is now taking advantage of the full resolution of the D/A converters; this also minimizes quantization noise in some cases.

NOS

Like the ORTF method (WFTD 4/17/97), NOS, which stands for Nederlandshe Omroep Stichting (that's the Netherlands Broadcasting System for all you monoglots) is a stereo miking technique. The NOS method is to place two cardioid microphones 30 cm (11.811023622 inches) apart and angled at 90 degrees from one another. This method produces more ambience than a strict coincident placement of mics, and fewer phase problems than widely spaced pairs of mics. Try the NOS method when recording ensembles or group performances, as well as on acoustic instruments. The center image of the recording will be nice and strong, but with a good amount of subdued room sound blended in as well... (for further information on mic patterns and placement, see inSync TTOTD 3/25)

Notch

A word used to describe a very narrow band of frequencies to be cut by an equalizer. When an EQ circuit has a very high Q (narrow bandwidth) it is sometimes referred to as a notch filter. Notch filters are commonly used to suppress feedback in monitor or PA systems, and are sometimes used to remove specific types of hum and noise in recordings.

NTSC

Abbreviation for National Television Systems Committee, which devised the color NTSC television broadcast system in 1953. NTSC is also commonly used to refer to one type of television signal that can be recorded on various tape formats such as VHS, 3/4" U-matic and Betacam. When color TV took over from black and white the Federal Communications Commission established the NTSC standard for broadcasts in the United States. This system was later chosen by a number of other countries including Japan, Korea, Philippines, Taiwan, Canada and Mexico. Many other countries later adopted other standards, such as PAL and SECAM. These various standards are not compatible with one another, though there are ways to convert from one to the other. There are lists of the standards in place for various countries available on the Web.

The NTSC standard of 525 lines of resolution per second combines blue, red, and green signals with an FM frequency for audio. In spite of all of its faults (it is sometime affectionately known as Never Twice the Same Color) NTSC provided a way to transmit color signals while still having them show up properly on black and white sets; a requirement set forth by the FCC. They accomplished the addition of the extra color information into a compatible black and white signal in part by slightly slowing down the frame rate causing SMPTE to devise the much maligned drop-frame video (see WFTD archive Drop Frame Time Code) standard. NTSC should begin to go the way of the dinosaur, however, with the impending arrival of HDTV, or high-definition TV. The FCC has ordered TV stations to be transmitting digital HDTV signals by 2003, and some will be broadcasting by 1999. A few years after that NTSC will, for all practical purposes, begin to disappear.