Speakers – Page 9 – My New Microphone

In order to hear what a microphone is doing, we need some sort of playback device, such as a loudspeaker or a pair of headphones. But do microphones need these playback devices in order to function? If a tree falls in the wood with no one to hear it, does it make a sound? Do Microphones Need Loudspeakers Or Headphones To Work? Loudspeakers and/or headphones are useful for monitoring or playing back amplified and recorded microphone signals. However, they're not necessary for proper mic functionality. Microphones convert sound into electrical signals and do so whether their signals are converted back to sound (via speakers/headphones) or not. To further answer your questions, let's discuss the basics of how microphones work and how they work with loudspeakers and headphones. How A Microphone Works As mentioned above, a microphone works independently of any loudspeakers, headphones, or other playback systems. How does a microphone work? A microphone converts sound into electrical signals utilizing a movable diaphragm. The mic diaphragm moves according to varying sound pressure and is a key component in the mic transducer. The movement of the diaphragm within the transducer causes the creation of an electrical microphone signal. Dynamic microphone transducers convert sound into mic signals via electromagnetic principles. Condenser microphone transducers convert sound into mic signal via electrostatic principles. In any given microphone, the moving diaphragm results in an electrical signal. From the diaphragm, the signal may travel through some other microphone components, such as transistors and transformers, before being outputted by the microphone. Passive microphones do not have any components that require power to function, while active microphones have at least one component that requires power. To better compare passive versus active mics, check out my article Do Microphones Need Power To Function Properly? So microphones, whether they're dynamic or condenser; or passive or active, work by outputting a mic level signal regardless of if their signal is actually sent to a playback system (loudspeakers, headphones, etc.) or not. For an in-depth read into how microphones work, check out my article How Do Microphones Work? (The Ultimate Illustrated Guide). How Loudspeakers And Headphones Work Just as microphones do not require a playback system to work, loudspeakers and headphones do not require microphones to work. How do loudspeakers and headphones work? Loudspeakers and headphones convert electrical energy (audio) into sound waves the propagate through the air (or another medium). Speakers/headphones have a diaphragm that moves according to the applied signal. The movement of the diaphragm creates sound waves. By the above description, we infer that speakers are basically large microphones in reverse. And this is true (of moving-coil dynamic microphones). Most speakers are designed with a conductive coil that accepts electrical audio signals. This coil is surrounded by magnets and, therefore, a magnetic field. As the AC signal is applied to the coil, the magnetic field causes it to oscillate. Since the coil is attached to the diaphragm, any audio signal applied to the speaker causes the diaphragm to move and sound waves to be produced. Although microphone signals are often amplified and sent through speakers, we know that speakers can work without microphones. Speakers often playback recorded audio (which could have been recorded with a microphone), but the record itself does not require any microphone for its signal to be sent to the speaker. On top of that, some recordings are made using absolutely no mics (synthesizers, etc.). For more information on loudspeakers and headphones, check out my in-depth article How Do Speakers & Headphones Work As Transducers? Getting The Mic Signal To The Playback System Although microphones do not require loudspeakers or headphones to function (and vice versa), these audio devices often work together. This is particularly true on stage and in the studio. So how do mics and playback systems work together? The signal flow starts at the mic and ends at the speaker, but some devices are required in between. The main devices (besides the mic and speaker) are amplifiers and the audio console, mixing board, or digital workstation (DAW). Gain Stages A mic signal requires at least two gain stages before it can effectively be projected by speakers and/or headphones. Gain stage 1: mic level to line level.Gain stage 2: line level to speaker level. What is mic level? Mic level is generally between 1 to 100 millivolts AC (-60 to -20 dBV). What is line level? Nominal line level is 1 volt (1 dBV). What is speaker level? Anywhere from 1 V (0 dBV) for small speakers and headphones to upwards of 100 V (40 dBV) for large speakers. Microphones output mic level signals. These mic level signals require amplification from a microphone preamp to become line level. Related article: What Is A Microphone Preamplifier & Why Does A Mic Need One? Line level is the professional standard audio level for use in mixing consoles and digital audio workstations. Mic levels are too low for these devices while speaker level is too high. Once the mic signal is processed through the console or DAW, it can be monitored through speakers. Speakers and headphones require speaker level audio signals. These signals range greatly depending on the size of the speaker but almost always require amplification from line level. Related articles:• Why Do Speakers Need Amplifiers? (And How To Match Them)• What Is A Headphone Amplifier & Are Headphone Amps Worth It? Headphone and power amps supply the necessary gain to boost line level signals to speaker level signals for playback and monitoring in headphones and loudspeakers/monitors. For more information on microphones signals, check out the following My New Microphone articles:• Do Microphones Output Mic, Line, Or Instrument Level Signals?• What Is A Microphone Audio Signal, Electrically Speaking? Let's look at the signal path from a microphone to the playback system in the studio and on the stage. Signal Flow From Mic To Playback In The Studio There will be two types of rooms in a typical studio setting: the live room and the control room. The live room is the soundproof room where the microphones record sound. The control room is set up with the console or DAW, where the mics are monitored and the audio is mixed. Studio monitors (loudspeakers) and headphones are commonplace in the studio environment to monitor the microphone signal. Monitors and headphones are popular monitoring choices in the control room, whereas headphones are the go-to in the live room (for bleed and feedback reasons). So how does the microphone signal get to the playback devices? This largely depends on the studio, whether the audio equipment is digital or analog, how many in-line processors are used, and other factors. Let's look at some basic signal flows for a microphone in the studio (note that this is a basic signal flow and that there are typically more devices in-line than shown): Studio (DAW) Signal Flow: Microphone To Headphones MicrophoneMic preampAnalog-to-digital converterDigital audio workstation inDigital audio workstation outDigital-to-analog converterHeadphone ampHeadphones Studio (Analog) Signal Flow: Microphone To Headphones MicrophoneMic preampAnalog recording console inAnalog recording console outHeadphone ampHeadphones Studio (DAW) Signal Flow: Microphone To Monitors MicrophoneMic preampAnalog-to-digital converterDigital audio workstation inDigital audio workstation outDigital-to-analog converterMonitor ampStudio monitors Studio (Analog) Signal Flow: Microphone To Monitors MicrophoneMic preampAnalog recording console inAnalog recording console outMonitor ampStudio monitors Signal Flow From Mic To Playback On Stage In live performance scenarios, the microphones are nearly always in the same room as the loudspeakers. On top of monitoring (which happens through loudspeakers and in-ear monitors), the microphone signal must typically be sent through loudspeakers for the audience to hear (unless the entire audience is fitted with headphones). Having monitors and loudspeakers in the same room as live microphones is a recipe for feedback. For more information on microphone feedback, check out my article 12 Methods To Prevent & Eliminate Microphone/Audio Feedback. Let's look at some basic signal flows for an on-stage microphone (note that this is a basic signal flow and that there are typically more devices in-line than shown): Stage (Digital Board) Signal Flow: Microphone To Loudspeakers MicrophoneMic preampAnalog-to-digital converterDigital mixer inDigital mixer outDigital-to-analog converterPower ampLoudspeakers Stage (Analog Board) Signal Flow: Microphone To Loudspeakers MicrophoneMic preampAnalog mixer inAnalog mixer outPower ampLoudspeakers Stage (Digital Board) Signal Flow: Microphone To Monitors MicrophoneMic preampAnalog-to-digital converterDigital mixer inDigital mixer auxiliary outDigital-to-analog converterPower amp [or wireless in-ear monitor transmitter]Monitors [or in-ear monitors] Stage (Analog Board) Signal Flow: Microphone To Monitors MicrophoneMic preampAnalog mixer inAnalog mixer auxiliary outPower amp [or wireless in-ear monitor transmitter]Monitors [or in-ear monitors] Related Questions Can you use a speaker as a microphone? A typical loudspeaker is designed just like a moving-coil dynamic microphone capsule/cartridge, only bigger and in reverse. Therefore, by wiring a loudspeaker backward, we may effectively use it as a microphone. Related article: How To Turn A Loudspeaker Into A Microphone In 2 Easy Steps. Can you use a microphone with a Bluetooth speaker? Although a typical microphone does not have Bluetooth capabilities, microphones of all types can be connected to Bluetooth speakers via Bluetooth transmitters. BAM is a great example of an XLR Bluetooth mic transmitter. Microphones with built-in Bluetooth also exist on the market. Related articles:• How Do Bluetooth Speakers Work & How To Connect Them• How To Connect A Wireless Microphone To A Computer (+ Bluetooth Mics)