The production of connecting wire in sound system

The production of connecting wire in sound system

At present, the input and output signal methods of audio equipment are basically divided into: Balance and Unbalance. Of course, it is possible to directly feed signals between balanced and balanced, unbalanced and unbalanced ports; in high-demand situations, the balanced and unbalanced ports must be connected to each other through a special converter. But in the actual project, as long as the signal line is not too long and the interference is not too large, the balanced port and the unbalanced port can be directly connected to transmit signals normally. In a sound system, in addition to the power transmission line between the power amplifier and the speakers, the signal connection lines between other devices should be transmitted in a balanced manner as much as possible, which can improve the anti-interference ability of the system and increase the effective transmission of the signal. Distance, line:

A. Signal line between balance and balance:

1. XLR male connector → XLR female connector: This kind of cable is used in professional audio systems. In terms of production, connect the three contacts 1, 2, and 3 between the male and female XLRs, contact 1. Connect to the shielding layer, contact 2 to the signal hot end (+ pole), and contact 3 to the signal cold end (- pole).

2. TRS Stereo Connector→TRS Stereo Connector: In terms of production, connect the head end (+ level), ring end (- level), and ground (Ground) between the two TRS stereo connectors. This kind of cable should actually be used in a large number of audio systems, but many sound engineers often use TS monophonic (acoustic) connectors instead because they save trouble. This is especially important, so that as soon as the signal transmission method is replaced, the balanced transmission is It becomes unbalanced transmission.

3. XLR male or female connector → TRS stereo connector: In terms of production, contact 1 (shield ground) of the XLR connector is connected to the TRS stereo ground (Ground); XLR contact 2 hot end (+ pole) is connected to the TRS head end (+ pole); XLR contact 3 cold end (- pole) butt to the ring end (- pole) of TRS. This is also a balanced transmission method, and is often used in audio systems.

4. XLR XLR male → XLR XLR male or XLR XLR female → XLR XLR female: this kind of cable is a bit special, it is most used for the signal connection between the power amplifier and the power amplifier or between the power amplifier and other peripheral equipment, and the production is also Connect the three contacts 1, 2, and 3 between the two connectors. Contact 1 is connected to the shielding layer, contact 2 is connected to the signal hot end (+ pole), and contact 3 is connected to the signal cold end (- pole).

Another point, in order to prevent "loop interference", we can vacate one of the contact 1 (shield ground) of an XLR connector in a signal line or the ground (Ground) of a TRS stereo connector under special circumstances. Do not connect, for example: a XLR XLR male to XLR female balanced line, we can vacate the XLR XLR female connector contact 1 (shield ground) to not connect, so as to avoid some interference between devices; The principle of the TRS connector is the same, just leave a ground contact arbitrarily. We used to weld a total of 6 solder joints when making such a balanced wire, but now we have 5 solder joints when we vacate one, but this method cannot be used for unbalanced wires.

 B. The signal line between unbalanced and unbalanced: generally refers to the signal line between TS monophonic (sound) connector → TS monophonic (sound) connector. This is an unbalanced transmission method. The head (+ level) and ground (Ground) two contacts between the two TS monophonic (sound) connectors are respectively connected.

C. The signal line between balanced and unbalanced: XLR male or XLR female connector → TS monophonic (sound) connector. In fact, the signal has become an unbalanced transmission method in this connection mode. In terms of production The contacts 1 and 3 of the XLR XLR connector are connected to the shielded wire and then connected to the ground (Ground) of the TS monophonic (sound) connector; the hot end (+ pole) of the XLR contact 2 is connected to the head end of the TS monophonic (sound) connector (+ pole). In the audio system, this kind of line is often used as a microphone line in the box karaoke system.

D. Speaker cable: In the connection between the power amplifier of the audio system and the speaker, the resistance of the speaker cable should be as low as possible. Use thicker and shorter wires and reasonable wiring. Current speakers generally use four-core connectors, and power amplifiers generally use four-core connectors or binding posts. In terms of production, connect the speaker's four-core connector 1 (+ pole) and 1 (- pole) to the power amplifier output (+ pole). And (-pole) is connected correctly. There are also some speakers or power amplifiers that use TS mono connectors and binding posts, and the connection principle is the same. Both are positive to positive and negative to negative. If the speaker is connected reversely, the speaker will be reversed, which will affect the sound quality and stability of the speaker. At the same time, avoid short circuit when connecting, otherwise it will damage the power amplifier equipment.

Generally speaking, the above are the types of connection cables that we often use in the system. Maybe everyone did not pay much attention to the connection of signal cables and speaker cables. Take signal cables as an example: in fact, it is as important as the blood vessels in the human body! And from the consideration of stability and long-term, we must use high-quality wires and high-quality plugs, and ensure that they are welded with high quality and trouble-free. Now, no matter how busy or tired I am doing engineering, I am used to soldering all the signal cables in the system by myself. If I use the signal cables soldered by others to connect to the system, there is nothing in my heart, as if you don’t know how to move forward. Like a landmine on the road, you don’t know which signal line will fail when, so relatively speaking, I can trust the stability of the bad equipment, but I don’t just believe in the quality. Unguaranteed signal cables and speaker cables!

Fourth, the connection sequence of audio system equipment:

After making all kinds of signal cables, it is necessary to prepare for device connection. Now there are more peripheral devices in the audio system. There must be a sequence when connecting. In fact, I have already introduced it in a series of articles last year. Summarize a few simple connection sequences:

1. The connection sequence of the bass system equipment: mixer (1-2 grouping) → equalizer → crossover → compressor → bass amplifier → bass speaker.

2. Auxiliary audio system equipment connection sequence: mixer (3-4 grouping) → equalizer → delayer (optional) → compressor → auxiliary speaker amplifier → auxiliary speaker.

3. The connection sequence of the main audio system equipment: mixer (L-R main channel) → equalizer → exciter (optional) → feedback suppressor (optional) → compressor → main speaker amplifier → main speaker.

4. The connection sequence of monitoring system equipment: mixer (AUX output)→equalizer→compressor→monitor speaker amplifier→monitor speaker.

The above 1 connection method can individually control the volume of the bass, so that the volume of the 1-2 group of the mixer can be turned up when we are slowly shaking or digo, and can be turned down when the singer is singing, which is very flexible; The second connection method can also control the sound of the auxiliary speakers; the third main speaker is of course used to output the volume from the LR total output of the mixer; the fourth monitor system, the standard is to output from AUX Volume, so you can flexibly adjust the volume of each channel of the mixer according to the requirements of the singer or band, but in a smaller sound system, the monitor signal can be taken directly from the main channel signal. The above 1 and 2 types of connection methods should also be noted: since 1-2, 3-4 are grouped, we have independently output signals to the bass system and auxiliary system from the corresponding output ports at the back, then 1-2, 3-4 Do not use the total volume output of the mixer for grouping, that is, do not turn on the switch from 1-2, 3-4 grouping to the total volume of the mixer.

Of course, we still have to flexibly arrange the order of equipment connection according to the needs and the number of equipment. The above order is for reference only.

Five, the main points of equipment connection:

The above briefly introduces the types, production and equipment connection sequence of various cables. In the specific connection of the equipment, facing the various and large number of equipment sockets, many sound engineers do not know how to start. It is actually very simple. , Everyone just needs to remember the following points:

1. Balance: The jacks on the back panel of most audio equipment are now balanced ports. We just choose to use the balanced line of the XLR XLR connector to connect the equipment or use the balanced line of the TRS 6.35cm stereo connector to connect the device. Equipment only.

2. Unbalance unbalanced side: Although most of the jacks on the rear panel of audio equipment are balanced ports, some devices still have unbalanced ports. For example, the output jacks of some electronic crossovers are marked with: Balance OUT (balanced output) and Unbalance OUT (unbalanced) output, so we can also use the unbalanced cable of TS 6.35cm mono connector to connect the equipment, as long as the line is not too long and the interference is not too large, this connection is still possible .

3. IN input and OUT output: Some beginners get dizzy when they see that there are so many jacks on the back of the device. In fact, there is a trick: No matter what audio device, it can basically be divided into "IN input" and "OUT output". Most of them, so we only need to look for "IN and OUT". Don't connect other unfamiliar sockets casually. In short, the connection device is like water: the water from the upstream will flow into the "IN input"; and the water flows downstream. The water will flow out through the "OUT output". Isn't this simple and clear?