How To Directly Connect A Microphone To A Speaker

Generally speaking, there are multiple devices and gain stages before a mic signal is sent to a loudspeaker and projected as sound. However, it is certainly possible to connect a microphone directly to a speaker.

How to plug a microphone into a speaker: To plug a microphone into a speaker physically, we must identify the speaker input connector and then use the proper cable adapters to send the mic output signal to the speaker input. Note that, without amplification, a mic level signal is far too weak to drive a loudspeaker.

In this article, we'll discuss how to properly and improperly connect a microphone to a loudspeaker.

Be sure to check out My New Microphone's article How Do Microphones Work? (The Ultimate Illustrated Guide)!

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Connecting A Microphone Directly To A Loudspeaker

Some powered loudspeakers will have mic inputs. In this case, it is easy to connect a microphone directly to the speaker and have the internal amplifier of the speaker boost the mic level signal to the speaker level.

Mic inputs are generally XLR. The same is true for loudspeakers with mic inputs. Therefore, when using a professional microphone with an XLR output, we only need an XLR cable to connect the mic to the loudspeaker!

Let's look at two examples of powered loudspeakers that have mic inputs:

The first is the Yorkville YX15PC, a 15-inch 300-watt powered loudspeaker. Let's take a look at the rear inputs of this loudspeaker:

To the right in the picture below, we see the mic input and the mic input gain dial above it. This input is an XLR input, which means an XLR microphone can be connected to this loudspeaker by a single XLR cable.

The second is the Electro-Voice ELX200-12P, a 12-inch 1200 Watt 2-way powered loudspeaker. Let's take a look at the rear inputs of this loudspeaker:

Here we see two combination inputs (XLR and 1/4″ TRS) that accept both line level signal and mic level signal.

Typically, as previously mentioned, microphones will connect via the XLR input, but mic level signals can also be sent through the 1/4″ TRS connection. Input one also includes an Aux In, which connects via RCA connectors.

We see gain knobs to the right of each input. As expected in a combo jack, the lower half of the gain applies reasonable gain to line level signals. In contrast, the upper half applies the gain necessary to boost the relatively low mic level signals.

This is by far the easiest way to plug a microphone into a speaker but is often not possible.

There are a variety of reasons why plugging a microphone directly into a loudspeaker will not work, including the following:

• Passive loudspeakers: passive loudspeakers do not have amplifiers and therefore cannot apply any gain to the mic level signal. A mic level signal is far too weak to drive a speaker.
• Active microphones: active microphones require some sort of power in order to function (typically DC bias or phantom power). Some active loudspeakers, like the Mackie SRM150, provide phantom power so that active microphones can function properly while being directly connected. However, many loudspeakers do not have such an option.

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Passive Vs. Active/Powered Loudspeakers

Let's briefly discuss the difference between passive and active/powered loudspeakers.

Powered loudspeakers have built-in amplifiers and require power to function properly. The powered speakers that feature mic inputs are designed with enough gain to boost a mic level signal to a speaker level signal.

Powered loudspeakers, therefore, do not require external amplifiers. However, they can still be used (and often are used) with multi-channel mixing boards and amplifiers.

Passive loudspeakers, on the contrary, have no internal amplifiers. They require no external power but need external power amplifiers to feed them speaker level signals (boosted from the mic or line level).

To simplify what was just said, I've added a small table below to describe the main differences between passive and active/powered loudspeakers:

	Passive Loudspeakers	Active Loudspeakers
Require External Power	No	Yes
Internal Amplifiers	No	Yes
Can Connect Directly To A Microphone	No	Yes

To learn more about active and passive speakers, check out the following My New Microphone articles:
• What Are The Differences Between Passive & Active Speakers?
• Why Do Loudspeakers Need Power & How Are They Powered?

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Passive Vs. Active Microphones

The terms “passive” and “active” also apply to microphones.

Passive microphones do not require any external power. They do not have any internal amplifiers (though passive step-up output transformers can boost the output voltage of a passive microphone).

Passive microphones include moving-coil dynamic mics and the majority of ribbon dynamic mics.

Active microphones require external power (either through DC bias voltage, phantom power, or a separate power supply). The active components within active mics include vacuum tubes, FETs, and the printed circuit boards of many microphones.

Vacuum tubes and FETs both act as impedance converters and as “pseudo-amplifiers” and require power. Vacuum tubes require more power and so tube mics are often designed with their own power supply unit. FET (and JFET) microphones can run on the relatively low 48 volts DC phantom power or even a lower DC bias voltage.

All condenser microphones are active, and so are USB/digital mics. Some ribbon dynamic microphones are active if they have active components.

For more information on passive and active microphones, check out my article Do Microphones Need Power To Function Properly?
To learn about phantom power, check out my detailed article What Is Phantom Power And How Does It Work With Microphones?

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Getting The Mic Level Signal To Speaker Level

We've discussed connecting a microphone directly to an active loudspeaker and using the speaker's gain to boost the mic level signal to speaker level effectively. We've also discussed the instances where this is not possible.

Let's now look at alternative (and arguably more common) methods of connecting a microphone to a loudspeaker and getting the mic level signal to the speaker level.

To simplify things, let's quickly discuss mic level, line level, and speaker level:

• Mic level: Mic level is generally between 1 to 100 millivolts AC (-60 to -20 dBV).
• Line level: Nominal line level is 1 volt (1 dBV).
• Speaker level: Anywhere from 1 V (0 dBV) for small speakers and headphones to upwards of 100 V (40 dBV) for large speakers.

To bring a mic level signal up to a speaker level signal, we must apply gain and amplify the signal.

We may amplify the signal from mic level to line level to speaker level. Alternatively, as is the case with connecting a microphone directly to the loudspeaker, we may amplify straight from mic level to speaker level.

To amplify a signal, an amplifier requires external power. The most common amplifiers in the chain of connecting a microphone to a loudspeaker are:

• Powered mixer: a powered mixer is capable of amplifying signal at its input and output and will often provide enough gain to boost a mic level input to a line level signal as well as a line level signal to a speaker level signal at its output.
• Power amplifier: a power amplifier can take line signals from a passive or active mixer (or microphone) and boost it to speaker level for the connected speaker level.
• Powered loudspeaker: a powered loudspeaker, as we've discussed, has an internal amplifier and will boost mic and line level signals to a speaker level that will drive the built-in speaker.

Now let's look at the various combinations we can use to not only connect a microphone to a loudspeaker but to do so in a way where the mic signal is able to drive the speaker:

1. Microphone into a powered loudspeaker.
   
   This means plugging a microphone directly into a loudspeaker, which we've discussed earlier.
   
2. Microphone into powered mixer into power amplifier into passive or active loudspeaker.
   
   A powered mixer can boost a microphone's signal to either line or speaker level. If the mixer outputs line level, the outputted signal may be boosted to speaker level by a power amp before reaching a passive or active loudspeaker.
   
3. Microphone into powered mixer into passive or active loudspeaker.
   
   A powered mixer can boost a microphone's signal to either line or speaker level. If the mixer outputs speaker level, the outputted signal may be sent straight to a passive or active loudspeaker.
   
4. Microphone into passive mixer into power amplifier into passive or active loudspeaker.
   
   A passive mixer will not amplify the mic signal, that would be the function of the power amp. If the power amp outputs a line level signal, a powered loudspeaker could boost that line level signal in order to drive the signal. If the power amp outputs a speaker level signal, it could drive a passive or an active loudspeaker.
   
5. Microphone into passive mixer into active loudspeaker.
   
   A passive mixer will not amplify the mic signal, but the passive mixer's output can be boosted by the active loudspeaker in order to properly drive the speaker.

For information on mic level, line level, and speaker level, check out my article Do Microphones Output Mic, Line, Or Instrument Level Signals?

My New Microphone has plenty of helpful articles on amplifiers and loudspeakers. Check them out by clicking the links below!
• Articles on amplifiers
• Articles on loudspeakers

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Related Questions

What do you plug a microphone into? Although microphones can plug into any type of audio input (given the proper adapter cables), they typically plug into mic inputs with mic preamplifiers. These inputs/preamps provide the necessary gain to bring the mic level signal to line level for use with other audio equipment.

For a detailed account of microphone connections and connectors, check out my article What Do Microphones Plug Into? (Full List Of Mic Connections).

Can you connect a microphone to a Bluetooth speaker? A Bluetooth speaker is designed to connect to a Bluetooth speaker. Regular microphones, however, require some sort of Bluetooth transmitter in order to connect to a Bluetooth speaker.

For more information on Bluetooth microphones and their wireless connections, check out my article How To Connect A Wireless Microphone To A Computer (+ Bluetooth Mics).

To learn more about Bluetooth speakers, check out my article How Do Bluetooth Speakers Work & How To Connect Them.