Question: What are some common consumer analog audio connections and their signal level?
Answer: Last week, we covered common pro audio connections. In this Question of the Week, we’ll be talking about common analog audio connections that are used in consumer-type applications.
In all things audio, there are input and output connections. Matching these connections properly is necessary in order to make your equipment work as intended/specified. The general rule is that a microphone should be connected to a dedicated microphone input, a line device to a line-level input, and headphones to a headphone output.
The two consumer-level connections we’ll be discussing are 3.5 mm and RCA, both of which are consumer-level standards for audio connections. These connections are normally unbalanced.
3.5 mm Connections:
3.5 mm connectors are also known as 1/8″ connectors – in audio, these terms are used interchangeably. The benefit of these connectors is that they are compact, so they can easily be integrated into consumer-level devices (such as mobile phones, tablets, DSLR cameras, computers, etc.).
However, these connectors have a variety of signal levels, pinouts (wiring configurations), and functions. This can make connecting 3.5 mm devices confusing. Also, the type of 3.5 mm connector (either male or female) does not necessarily determine the directionality of the audio signal(s), which can add to the confusion. The common types of 3.5 mm connectors are listed below:
It is easier to identify the pinout of a 3.5 mm connection with a male connector. In the pictures shown, you see that a mono connection has only a Tip and Sleeve. In dual-mono and stereo connections, you see a Tip, Ring, and Sleeve. In the CTIA TRRS connection, you see a Tip, two Rings, and a Sleeve. However, what type of connection is the 3.5 mm female connector? Is it a microphone input? A headphone output? Something else? The fact that you cannot easily see the pinout for the female connector is what makes a connection mismatch so common.
So how does one determine if they are properly connecting their 3.5 mm devices? Usually, the owner’s manual of the recording or playback device (mobile phone, tablet, DSLR camera, computer, etc.) will determine how and what to connect to an available audio jack. Quick instructions for connecting a 3.5 mm microphone to a Mac can be found by clicking here, and for connecting a 3.5 mm microphone to a PC by clicking here.
In any scenario, it is imperative that you properly match your connections. A mono microphone should get plugged into a mono input, stereo headphones into a stereo headphone output, etc. A common question we hear is “Why doesn’t my microphone work when connecting it to my mobile phone?” It seems completely logical that since the connectors are the same size, they should work together, so why don’t they? The reality is that the user is plugging a microphone into what was meant for a headphone or headset. In other words, you’re essentially connecting an output to an output. A mismatch is created, and the microphone doesn’t work. However, there is a work-around for this particular scenario, detailed here.
RCA stands for Radio Corporation of America. These connectors are typically used with turntables, and because of this they are often mistakenly called “phono” connections. RCA connections are typically labeled as red and white (sometimes red and black). The red usually carries the right signal, the white or black typically carries the left signal. Although not always the case, the male RCA typically carries the output signal, and the female the input signal. If a mismatch occurs with a turntable, it’s usually the result of using or not using the dedicated “phono” inputs on a receiver. These “phono” inputs are labeled as such because they have a phono preamplifier associated with them. Turntables require phono preamplification, and all Audio-Technica turntables feature a selectable built-in preamplifier for the RCA connection. For proper operation, set the preamp switch to Phono when connecting to a labeled RCA phono input, and set it to Line when connecting to an input that’s not specifically labeled as a phono input. Most other RCA connectors are simply looking for a line-level signal. Because of this, a mismatch in such RCA connections is not common.
Adapting any of these connections might be possible. Audio adapters are widely available. However, using them is one of the most common ways of creating a mismatched audio connection. If it is possible to adapt the connection, then it is extremely important to adapt properly or adverse effects will be experienced. As a general rule, a mono connection can be split once into dual-mono connections, but a dual-mono or stereo signal should not be summed into a mono connection without the use of a summing block. Therefore, regardless of the connections you use, you should not try to sum audio signals with a Y cable.
If you are uncertain about how to adapt these types of connections, or if you have any other questions, you can always contact the Audio Solutions Department and we’ll be more than happy to assist you!