re: Help, I need some terminology (& subwoofers)
Directly powering a
loudspeaker's High and Low (
Biamp); or High, Mid, and Low (
Triamp) components. Also known respectively, as two-way and
three-way speaker systems.
I would have to disagree with the last part as most
speaker systems are two or
three way even if run
passive full range. There are also many
bi-amp/
three-way systems. In the most general sense, two/three/four way refers to the number frequency ranges the
speaker system addresses through different drivers. A two-way
system would likely have a
woofer and
tweeter, a
three-way system a
woofer, squawker and
tweeter (or
subwoofer,
woofer and
tweeter) and a four-way
system typically a
subwoofer,
woofer, squawker and
tweeter.
The bi/
tri amp aspects relates to using different amplifiers to
power these different frequency ranges. A 'full range'
three-way system would
power all frequency ranges off one
channel of amplification and use an internal
crossover in the
speaker to divide the signal to the
woofer, squawker and
tweeter. A bi-amped,
three-way system would use an external
crossover to
send the low frequency portion of the signal to an
amplifier that then powers the
woofer and the higher frequency content of the signal to a second amp to
power the squawker and
tweeter. A tri-amped
system would also use an external
crossover to divide the signal into the low, mid and high frequency components with each being sent to a separate amp
channel and then to the
woofer, squawker and
tweeter, respectively.
On the
cone sizes, this is the problem of trying to keep things basic as while there may be some common
cone sizes seen for each, the terms "
subwoofer", "
woofer", "squawker" and "
tweeter" actually refer to the frequency range the
driver reproduces and not to the
cone size. A
subwoofer is used to reproduce very low frequencies, typically below 100Hz or so, and is most commonly a separate device. Subwoofers are typically physically large and use larger cones, 15" and 18" diameter are common, however the use of high excursion (large movement) drivers or other special technologies can also be used, often allowing the use of smaller diameter drivers and/or enclosures. There are also a number of different types of subwoofers (front loaded,
horn loaded, isobaric, free air,
etc.) that relate to the enclosure and 'loading' of the
driver itself. A
woofer reproduces low frequencies and is most commonly part of a multi-driver
speaker. The size of a
woofer driver can differ dramatically based on the application, the
woofer in a computer
speaker may be 3" or 4" while in sound reinforcement products 12" and 15" diameter woofers are common. Drivers that reproduce the mid range and especially speech frequencies are called squawkers and today are most often seen as the middle part of a packaged
three-way speaker. These may be cones, typically smaller than the
woofer driver, or a
horn. A
horn consists of a physical
horn used to help couple the
driver to the environment and to provide some directionality to the sound along with a
driver mounted to the rear of the
horn, Tweeters handle the high frequencies and can be a
cone, a
horn or some other less common forms (ribbon,
etc.). Tweeters are usually physically smaller, however some horns may be quite large depending on the
level of directional control desired.
A
crossover is in its most basic form a series of electronic filters used to divide an audio signal into a number of frequency range components. A two-way
crossover splits the signal into it's low and high frequency components, a
three-way crossover into the low, mid and high components and so on.
Crossover are typically either
passive, normally a
circuit inside a
speaker that internally divides a single source signal and sends the appropriate portion to the
driver(s) in the
speaker, or active, a separate box that does the frequency dividing prior to the amplifiers.