Question: What are some common pro analog audio connections and their signal level? Answer: Last week, we covered balanced vs. unbalanced connections. In this installment of Question of the Week, we’ll be talking about common analog audio connections (microphone, instrument and line) that are used in professional applications. Next week we’ll take a look at connections for consumer applications. As you might imagine, professional connectors come in many shapes, sizes, and pin-out configurations. The most important thing to remember when reading this post is that audio is electricity, and the connectors must be properly matched and handled with care. Additionally, please refer to the product manuals for each device you are using to ensure proper connection, both in terms of signal level and physical connector type. Common Professional Connectors Professional Microphone Connectors are typically one of the following types: standard XLR, TB3M, or TA3F (the latter two known as Mini-XLR). Almost always, professional connections are “balanced.” With XLR cables, the pins generally point in the direction that the audio signal is travelling – XLR-M (male) are mostly output connectors and XLR-F are mostly input connectors. This directionality doesn’t always apply to TA3F and TB3M connectors, however. All three of these connection types are used mostly to carry microphone-level signals. XLR-M and XLR-F Connectors TB3M ConnectorTA3F Connector XLR-M and TA3F Connectors Sometimes, microphone connections are made by using XLR to ¼" TS cable, in which case the connections are typically (but not always) “unbalanced” and do not supply phantom power to condenser microphones that require it. Remember, if a microphone requires a power module, then that power module is necessary for use. Microphone level is the typical level (strength) of a microphone signal. Mic level is generally significantly lower than line level, although that is not always the case. Depending upon the microphone and the sound pressure level (SPL) injected into the microphone, the level may range from a few microvolts for a whisper, up to several volts for a microphone in front of a guitar cabinet. It is important to connect microphones to microphone-level inputs, not directly to line-level or instrument-level inputs. If you must plug a dynamic microphone into a high-impedance instrument input, you’ll need to use a proper transformer, like the CP8201, to make it work. Professional Line or Instrument Connectors are typically ¼" TS or TRS. TS is sometimes considered mono, and TRS is sometimes considered stereo. TS is mono and unbalanced, while TRS can be either mono or stereo (unbalanced or balanced). TS Mono Connection TS Mono Connection Detail Line level refers to the typical level (strength or amplitude) of the audio signal from line devices, such as digital audio players, televisions, mixers, signal processing equipment, and other consumer and professional audio gear. Line level is typically much stronger than microphone level. There are two types of line levels: consumer and professional. Consumer line level is generally thought of as a signal whose level is at -10 dBV (0.316 volts). Digital audio players and televisions are examples of consumer line-level equipment. Professional line level is generally thought of as a signal whose level is at +4 dBu (1.23 volts or significantly higher). Signal-processing equipment and professional mixing consoles are examples of professional line-level equipment A last word of advice: regardless of the connectors you use, you should not try to sum/combine audio signals with a Y cable. That concludes this QOTW. Feel free to check in with our Audio Solutions Department to get answers to all your audio connection questions.