ANALOG CONNECTIONS
Balanced vs. Unbalanced
Unbalanced Connections - carry a positive signal and a ground, sometimes referred to as a shield. Unbalanced connections are much more susceptible to noise and interference from the external environment than balanced connections, but the circuitry is much cheaper and simpler to build than that in balanced systems.
Balanced Connections - carry a positive signal (hot), an inverted negative signal (cold), and a ground (shield). When a piece of equipment has balanced inputs/outputs it inverts the negative signal so that any noise picked up by the cable from long cable runs, other electronic equipment in the area, lights, etc., will be cancelled out when the negative signal is re-inverted at the receiving device.
Connection Types
Balanced connection
Use to primarily to connect microphones to mic preamps / mixers / interfaces. Also used as an interconnect for professional level equipment such as compressors, eqs, preamps, effects devices, etc.
TRS = Tip/Ring/Sleeve
Balanced connection
Used mostly as an interconnect for mid to pro level equipment. (Preamp / compressor / eq / efx) The configuration is identical to an XLR cable.....positive, negative, ground.
Balanced connection
Carries 8 separate balanced connections over one cable with 25 pins. Used to connect professional multichannel equipment such as recording consoles, patchbays, AD/DA convertors, ProTools HD interfaces, etc.
Often there is a DB25 on one side and 8 XLR or TRS on the other. This is to connect to a patchbay and then breakout to all the individual equipment.
Bantam / TT (Patch cables)
Balanced connection
TRS - smaller than 1/4" larger than 1/8" headphone jack.
Used on professional studio patchbays.
Unbalanced connection
Used mostly to connect consumer equipment such as home stereo receivers, CD / tape / record players. Consumer equipment functions at at a lower 'standard operating level' than professional recording equipment. (-10dBv for consumer equipment as opposed to +4dBu for professional equipment.)
TS = Tip/Sleeve
Unbalanced connection
Used mostly as an instrument cable. Primarily to connect a guitar to an amplifier, keyboard to an amp or direct box, etc.
1/4 TS cables are also used as interconnects on entry/mid-level (or prosumer) equipment. (Art, presonus, entry level focusrite, for example)
Unbalanced connection
An insert cable has a TRS connector on one end, and two TS connectors on the other end. Insert cables are mainly used in conjunction with 'inserts' on mixers, but maybe some audio interfaces. They are also referred to as send and receive cables because they send the signal out to the INPUT of a device, and then back from the OUTPUT of that device over one cable. Don't be confused by the TRS on one side of the insert cable. An insert cable carries two SEPARATE unbalanced signals, not a single balanced signal like a regular TRS cable. The TIP carries one signal to one of the TS plugs, and the RING carries another signal to the other TS plug. Equipment that utilizes this type of cable often labels whether the tip or the ring is used for input or output.
Used for live sound and stage use. Connects the power amplifier to the speakers. The connectors lock in place so there is no worry of them coming undone. They can carry much higher current, and because the connections are covered there is no risk of getting shocked. Speakon can actually have 2, 4, or 8 connections in the one cable, so you can run a biamplified system on one cable.
DIGITAL CONNECTIONS
Analog cables carry a continuous analog signal that represents the frequency and amplitude of the waveform, just like a microphone or analog tape. Digital cables transfer binary encoded digital information of the audio. (1s and 0s) Everything above a designated voltage is representative of a '1' and everything below a designated voltage is designated a '0'.
Digital Connections and 'Protocols' (Digital format types - meaning how the information is packaged and transferred.)
S/PDIF CoaxialConnector: RCA
Carries 2 channels of digital audio over one cable. (stereo left/right)
Can transfer 44.1 or 48k sample rates (sometimes referred to as 1x rates). It is possible to use regular analog RCA cables for spdif coaxial, but the impedance rating of the cable is different so should be avoided for long runs. Short runs will not notice a difference.
S/PDIF Optical
Connector: Toslink
Carries 2 channels of digital audio over one cable. (stereo left/right)
Usually limited to transfer 44.1 or 48k sample rates (1x rates)
Instead of a voltage representing the 1 or 0, a light beam does. Light on = 1, light off = 0.
S/MUX
Connector: Toslink
Carries up to 4 channels of digital audio over one cable.
Can transfer 44.1/48k or 88.2/96k sample rates (1x or 2x rates)
Often seen in multichannel preamps that have convertors and digital outs.
ADAT Lightpipe
Connector: Toslink
Carries up to 8 channels of digital audio over one cable.
Can transfer 44.1/48k sample rates (1x rates)
Often seen in multichannel preamps that have convertors and digital outs, interfaces, ad/da convertors, and digital consoles.
Connector: XLR
Carries 2 channels of digital audio over one cable.
Can transfer 44.1/48k or 88.2/96k or 176.4 or 192k sample rates (1x, 2x, or 4x rates). Professional digital interconnect for high resolution audio. It is possible to use regular mic cables for AES, but the impedance rating of the cable is different so should be avoided for long runs. Short runs will not notice a difference.
AES (AES3, AES/EBU)
Connector: DB-25
Carries 8 channels of digital audio over one cable.
The same info is transfered as the AES xlr variation above, the multiple pin connector just allows for more channels, similar to the analog example at the top of the page.
Connector: SC type
Carries up to 64 channels on one cable
Can transfer 44.1/48k or 88.2/96k sample rates. (1x or 2x rates)
More recent than the other digital formats, but becoming very prominent.
Connector: BNC
Carries up to 64 channels on one cable
Can transfer 44.1/48k or 88.2/96k sample rates. (1x or 2x rates)
More recent than the other digital formats, but becoming very prominent. MADI optical is more common than MADI coaxial.
Connector: BNC
Carries ZERO channels of audio!! Wordclock is used to transmit clocking information to all the different digital devices in a system. There can only be one 'master clock' signal providing the digital clock pulse that all digital equipment references to ensure each sample pulse is locked between each of the devices. All other digital gear not set as 'master' is 'slaved' to reference the incoming clock signal. A consistent clock signal helps eliminate digital clicks and pops, and reduce jitter.
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Try not to be confused by the fact that several different types of connections are made with the same type of cable/connector in both the analog and digital world. That doesn't mean you can hook up an analog XLR out to an AES digital in because they share a connector type, or a wordclock out to a MADI in, or a Lightpipe out to a S/PDIF in, etc. It is just all the more reason you need to know all of these things exist, and when each is being used or needed.
Good luck!
