Music Making

All About Audio Cables Jack Connectors

All About Audio Cables Jack Connectors

all the usual audio cables at a glance. Which cable is for what and what is in doubt the better solution for you? What do digital formats do? A wealth of practical knowledge and expert tips on audio-cables for musicians and other music-related topics.

The most important connections for analog and digital audio signals are listed below. You will get all the practical information about cables, plugs and sockets as well as interface formats in the homestudio , in the pro space or on the stage.

Audio cable for analog signals

Formats

1. Jack

The most important format for musicians, producers and sound specialists is probably the Klinkenkabel. Especially the variant with the diameter of 6.35 mm – usually rounded off with titled “6.3 mm”.

The more compact version – “small latch” or “mini-link” – measures exactly 3.5 mm. It is used more rarely in professional audio technology, but it has always been the first choice for MP3 players, tablets and smartphones or other portable devices.

Since even large jack sockets are much space-saving than XLR (see below), they will not disappear so quickly from the audio technology. Large audio interfaces, drum machines, keyboards, etc. with many inputs and / or outputs for individual channels could hardly be constructed without such compact sockets. Not to mention small mixing consoles for small studios in contemporary homerecording .

Jack connections can provide different types of signal transmission – for example, mono or stereo via a single plug, depending on how it is designed. This is exactly what you will find in text and image.

TS

  • Mono, asymmetric

TRS

  • Mono, symmetrical or asymmetric
  • Stereo, asymmetrical
  • “Return and return” when connecting effects devices via a single cable

TRRS

  • Mono, symmetrical or asymmetric
  • Stereo, asymmetrical
  • Additional channel for headset cable microphones

2.XLR

The unrivaled standard in many areas of professionally oriented audio technology, especially for the connection of microphones and loudspeakers.

The overwhelming majority of devices use XLR connections with three poles, ie three possible lines for signals. These end in the male terminals (“male”) in small metal pins (“pins”), which are inserted into corresponding holes in the female socket (“female”). More than three poles are found in the audio signal transmission on tube microphones (there are usually five).

XLR is more robust and less susceptible to dirt and dust as the contact surfaces are surrounded by the housing. When connecting, high voltage peaks are avoided. In short: if possible, XLR should always have the advantage of using the jack connections, and if it is only at one end of the cable.

You can assume with great certainty that the signal can be transmitted symmetrically with an XLR cable – only in very rare exceptional cases are they limited to an asymmetrical transmission. Devices with functionally cut XLR sockets are not known to us.

3.Combi-Jacks

These sockets are a space-saving solution to accommodate inputs / outputs in the two previously illuminated formats on one device. Here is the opening for jack plug in the middle, while around the three holes and the ring for XLR are to be found. Disadvantage: Only one cable can be connected at a time.

4.RCA

The international name, which is also not unusual in this case, is “RCA” (by ” R adio C orporation of A merica”). This format can be found mostly in the entertainment electronics (eg stereo) and in devices for homerecording at an amateur level. But also for mixing consoles for connecting recording devices or for audio interfaces and controllers for DJs.

For audio transmission, RCA connections are practically always in the form of a pair – so the left and right channels of a stereo signal can be transmitted, because, unlike the jack, a single plug always has a single signal.

With Cinch only asymmetrical signal transmission is possible. This makes this format more susceptible to noise than XLR and TR (R) S jack connections. This circumstance, possible manufacturing inaccuracies due to lack of standardization as well as small electrotechnical disadvantages in the handling lead to a clear judgment: at least in the (home) studio RCA should only be used if it is technically or financially no different.

5. Two-core PA

In the case of a detour to the event technology , the use of Two-core PA connections is more and more common when it comes to the cabling of a PA system .

Modern PA systems offer sound quality on the top level. This matter of fact was motivation enough for us to specifically develop speaker cables for this application, so that high end PA systems can fully exert their potential. Also outstanding to connect guitar or bass amplifier heads with speaker cabinets. Due to the large diameter of the solid core conductors, this cable is relatively stiff. The application is therefore restricted to permanently installed PA systems.

The larger contact areas in comparison to jack or XLR connections ensure a smaller transition resistance and a higher load carrying capacity. Furthermore, the protection against contact in the event area is very important – amplifier power up to the kilowatt range is not uncommon for large events, so the noise and noise generated by other cables would be fatal.

Symmetrically Asymmetrical

The so-called symmetrical (“balanced”) transmission of a signal ensures a significantly lower susceptibility to noise. Especially when using long cable lengths. In order to transmit symmetrically, all three components – both devices and the cable – must be designed for this purpose. For the cable, this means that for a mono signal two wires and a ground conductor are required. Just like for asymmetrical stereo.

Levels

Let us first consider the output of audio devices and instruments. There are four standards that produce differently strong levels on average – in the following sorted in ascending order.

  • Microphone level
  • Instrument level 
  • Line level from keyboards, synthesizers, drum machines, and more
  • Loudspeaker level of amplifiers for guitar, bass

The key point is that an input on a receiving device usually “expects” a certain one of these levels. Examples: A guitar amplifier is designed for power supply with instrument level, a microphone pre-amplifier for microphone level and a speaker for line level.

Audio cable for digital signals

In a digital audio signal, a sequence of numbers is sent at regular intervals. Each of these numbers represents the level (amplitude) at a particular time within the signal. Example: With a bit rate of 16 bits, the margin between total silence and the digital maximum level is solved in 65.536 (216) steps.

How fast the sequence of these numbers is, is determined by the so-called sample rate of the audio data from the transmitter. For example, with audio samples with a sample rate of 44,100 hertz (44.1 kHz), it is 44,100 times per second.

Analog signals, on the other hand, are not as graduated. With them the signal theoretically flows infinitely finely – but this applies in practice only to the time axis (corresponds to the sample rate with digital audio signals). Because at the level of the amplitude and thus the level of the electrical voltage, all devices have technical limits.

Formats

1. Optical

This format was developed by Toshiba in 1983 (» TOS hiba- LINK «) and belongs to the category of optical fibers – here no electric current but light is passed through. TOSLINK therefore also operates under the simple name of “optical cable”

This type of signal transmission is insensitive to interferences by radio waves or electromagnetic interference and does not cause ripple loops. This way, a power supply, power cable and more can be routed directly next to a TOSLINK cable.

The standard format for the plug and socket is called “F05” and only transmits the light waves. The “Mini-TOSLINK” version also transmits an analog signal via a small jack plug (see above) – the light waves enter the cable through the hole in the plug tip. Many laptops have a mini-TOSLINK socket for transmitting a surround signal with the described hybrid cables.

Digital interface formats via TOSLINK:

  • S / PDIF
  • ADAT
  • MADI

2. Coaxial

The digital signals are conventionally transmitted with electrical current. Note that this type of cable looks in the digital context as an ordinary cinch cable for analog signals, but only the plugs and sockets are identical – the difference is the so-called coaxial (concentric) construction of the cable.

Unbalanced, shielded digital cable with an impedance of 75 Ohm. Depending on the choice of connectors, it can be used for different data formats such as S/P-DIF, MADI or Wordclock.

  • solid core conductor for signal and ground
  • silver-plated, oxygen-free copper conductors
  • pigment and plasticizer-free high purity polymers
  • shielded
  • impedance 75 Ohm

3. XLR for AES / EBU

However, normal microphone and loudspeaker cables are not suitable for AES / EBU transmission. Instead, cable conductors with a line impedance of 110 Ω should be used, otherwise signal reflections and thus synchronization problems may occur between the connected devices. Conversely, the AES / EBU cables with 110 Ohm work without problems for analog transmissions.

Interface formats

The four most important interface formats – the “languages” in which the signals are interpreted – are S / PDIF, ADAT, AES / EBU and MADI. For homerecording and semiprofessional use, the first two are usually completely sufficient. MADI, in particular, is designed for a very high number of channels (up to 64) and thus for live operation, large sound studios, radio and television stations, etc.

In the following table, you can see how many channels you can transmit in which quality. Only the maximum possible specifications are listed – some devices are only able to send / receive S / PDIF with 16 bits or MADI with 56 channels.

Maximum bit depth Channels / max. Sample rate
S / PDIF 16 bit (20/24 bit optional) 2 channels with 48 kHz
ADAT 24 bit 2 channels with 192 kHz
4 channels with 96 kHz
8 channels with 48 kHz
AES / EBU 24 bit 2 channels with 192 kHz
MADI 24 bit 16 channels with 192 kHz
32 channels with 96 kHz
64 channels with 48 kHz

Multicore – Stagebox & Loom 

In studios and the live area is transmitted on many channels at the same time – from a fixed point A to a fixed point B. So it is a question of grouping many small cables into a large one instead of laying dozens of individual cables. The English name is “multicore”, because several sound lines run at the core of such cables.

Multicore cables are roughly divided into two variants – as a stage box and as a loom. The former is a box with several sockets (with XLR typically 16 – 64 pieces), from which a single, very thick Multicore cable goes off. At the end of this cable “splits it open” and discharges into the individual plugs. In a loom, on the other hand, both sides are “spliced”.

MIDI

MIDI cable – formerly the only variant for the transmission of musical control data. Today there are also wireless MIDI via Bluetooth radio traffic, but here it is to be synonymous audio cables in the broadest sense.

The plug and the socket are for today’s conditions relatively clumsy. However, the stability is satisfactory and apart from small and smallest devices, one to three MIDI sockets can be found everywhere.

MIDI jack is not equal to MIDI jack – these three are to be found in the wild:

  • In – This is where MIDI signals are received from other devices
  • Out – Sends MIDI signals to other devices
  • Thru – Sends received MIDI signals to another device
MIDI via USB
Many manufacturers prefer to use a USB port (Type B) today. This allows the MIDI connection to your computer or (via adapter) to smartphones & tablets. Now you can send MIDI notes, automation data, etc. from a DAW software or similar music programs / apps, or vice versa. But then no additional MIDI interface or no audio interface with integrated MIDI connectors needed. As a rule, the required USB MIDI driver is automatically installed after you plug the device into your Windows computer or Mac.

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