Help, I need some terminology (& subwoofers)

Ok, so i'm the sound guy for my Jr. High and I really enjoy it and all but I'm somewhat confused when I read some of the posts on here. Please use the simplest terms possible when explaining it to me because I run on no sleep and it's difficult to keep up.

What are/is...

Impedance
Balanced/Unbalanced
Crossover (referring to monitors or speakers)
Biamping/Triamping
the different size cones such as subwoofer, woofer, etc.


Thanks.
 
re: Help, I need some terminology (& subwoofers)

http://www.controlbooth.com/forums/sound/5237-impedance.html

Balanced/Unbalanced
http://www.controlbooth.com/forums/sound/12754-balanced-unbalanced.html

Crossover (referring to monitors or speakers
http://www.controlbooth.com/forums/glossary/11175-crossover.html

Biamping/Triamping
Directly powering a loudspeaker's High and Low (Biamp); or High, Mid, and Low (Triamp) components.

the different size cones such as subwoofer, woofer, etc.
Speaker Cones range in size from 2" to 18". The larger the size, the more capacity for moving more air and thus better suited for the longer wavelengths of lower frequencies.
 
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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.
 
re: Help, I need some terminology (& subwoofers)

excellent explanation Brad Weber, but as you chose to dispute/add to what Derek wrote, I will add that some times there might be mulitple speakers of the same frequency in a cabinet, and that sometimes a 4 way system may not have a subwoofer, but have a supertweeter instead.
An example would be my home theatre, which has four cabinets that have a 4way 6 speaker array. Ther is a 14" woofer, two 8" midrange, 2 horn tweeters, and 1 horn super tweeter with directional radiators. The cabinets were purchased overseas and manufactured by Sansui in 1973. My center channel is a little more traditional, with an 8" woofer and a directional horn tweeter and a 15" subwoofer.
It sure takes up a lot of space, but has the sound that i like.
 
re: Help, I need some terminology (& subwoofers)

excellent explanation Brad Weber, but as you chose to dispute/add to what Derek wrote, I will add that some times there might be mulitple speakers of the same frequency in a cabinet, and that sometimes a 4 way system may not have a subwoofer, but have a supertweeter instead.
There are definitely some speakers that have multiples of the same drivers, look at modern column arrays that have multiple identical 'woofers' and often over a dozen identical tweeters. There are also some speakers that have dual woofers that use both woofers at the lowest frequencies but then low pass one so the speaker transitions to just one of the woofers at the higher frequencies end of the low frequency band. Or speakers like mine at home that have a smaller 'active' woofer and then a larger unpowered 'passive' woofer. Then there are coaxial speakers that have the drivers aligned in front of one another, sometime using the lower frequency driver as part of the high frequency horn or waveguide. Or any of a number of other configurations, it would be impractical to try to address them all. But for all of them you still pretty much still break the signal up into two or three frequency bands and distribute those to drivers for each of the bands.

Supertweeters are indeed an element in some audiophile and club/dance systems, that is why I was careful to define the examples I used as being typical or common, but definitely not all the potential options. I think that in the context of this forum, and large scale sound reinforcement systems in general, subwoofers are much more common than supertweeters.
 
re: Help, I need some terminology (& subwoofers)

The 21" is making a comeback.
;)

I heard a 4x 21" sub the other day. A single one shook the entire warehouse. And that was just off a Macro-Tech 1200.
 
re: Help, I need some terminology (& subwoofers)

I heard a 4x 21" sub the other day. A single one shook the entire warehouse. And that was just off a Macro-Tech 1200.

Horn- or manifold-load that thing and it'll be even more impressive.

There's a local venue built back in the '60s that had a bass horn built into the architecture. The throat held something like four 18s (maybe 21s, maybe) and the mouth was something like 10 feet by 40 feet. I never had the chance to hear it, but I'm told it was impressive back then.
 
re: Help, I need some terminology (& subwoofers)

I remember walking into a friend's house for a jam session and finding his system had something like a 36" organ speaker in a custom enclosure for the sub. Standing in front of it was reminiscent of the Back to the Future scene.
 
re: Help, I need some terminology (& subwoofers)

Like the Community CB594 that used a 15" 'compression' driver and was 43"x53" at the mouth with a 68" depth? Or this, Matterhorn, 40 low frequency drivers each with a separate 1,000W amplifier in a tapped horn configuration that uses an 8'x8'x20' shipping container as the enclosure (so yes, it is portable). -3dB at 12Hz and flat from 15Hz to 80Hz with an output of close to 160dB at the mouth of the horn and over 105dB at 250m (820'). Built because the military wanted a low frequency device with rather outrageous specific specs and no one else came up with a solution so Tom Danley took it as a challenge. I had a chance to stand inside it while they played a 15Hz tone (not at full output) and the effect was pretty amazing, not many horns you can walk around inside of. Just for fun the guys at Danley also temporarily mounted one of their SH50 boxes inside it for awhile to make it the world's largest truly full range, coaxial speaker. I've asked if I can borrow it for our next block party. ;)
 
re: Help, I need some terminology (& subwoofers)

Horn- or manifold-load that thing and it'll be even more impressive.

There's a local venue built back in the '60s that had a bass horn built into the architecture. The throat held something like four 18s (maybe 21s, maybe) and the mouth was something like 10 feet by 40 feet. I never had the chance to hear it, but I'm told it was impressive back then.


Its impressive now! This sub system was designed/installed by Royal Device and is quite a feat of engineering. Click the link below and scroll down. Quite a project...

IL PIU' GRANDE SUBWOOFER DEL MONDO

Some info in english:

Meet the World's Most Insane, Intriguing and Ultimately the Biggest Subwoofer - Prepare to be blown away. Literally. - Softpedia

Also Richard Clark (of car audio fame) built this subwoofer several years ago - Scary...
Three pages with photos here:

http://www.digitalgrabber.com/content/view/216/3/1/0/

3
 
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