Camera Audio Cable: How to Add a Microphone to a CCTV Camera

If your camera has a camera audio cable (a lead marked AUDIO IN, usually ending in an RCA plug), you can add sound by connecting a powered, or "active", microphone to it. The audio input expects a signal that has already been amplified, so a plain passive microphone gives silence or a faint hiss. Once the mic is wired and powered, you still need to switch audio on in the app before anything is recorded.

This guide covers how to identify the lead, choose the right type of microphone, wire it safely, and test it. If your camera already has a built-in microphone and the clips are simply silent, the fix is different — see why security camera recordings have no sound.

Step 1: Work out what audio leads your camera actually has

Many cameras sold for homes have a microphone built into the body and no external audio lead at all. Fixed outdoor models with a bundle of cables coming out of the back (often called a pigtail) are more likely to have one. Look at each connector on that bundle and read the small tags or printed labels:

• AUDIO IN or MIC IN: this is where an external microphone connects. On most models it is an RCA (phono) socket or plug, often white or red.
• AUDIO OUT or SPK: this is for a speaker. A microphone plugged in here will not work.
• ALARM IN / ALARM OUT: these are for sensors and sirens, not sound, even though they can look similar.
• Power (DC) and network (RJ45): the usual leads you already connected during setup.

If none of the labels says audio, check the manual or the label on the camera body. If there is no audio input listed, the camera cannot take an external mic, and no adapter will change that. In that case, the realistic choice is a security camera with microphone built in.

A camera with a built-in mic may also have an AUDIO IN lead. On some models, plugging something into it switches off the internal microphone; on others both are mixed or the menu lets you choose. The manual for your model is the only reliable source on this.

Step 2: Understand why a passive mic gives silence

This is a common reason behind "I added a mic and nothing happened".

• A passive microphone (like a basic dynamic or headset mic) produces a very small electrical signal. A computer or a mixing desk boosts it with a preamp before it is usable.
• A camera's audio input is usually a line-level input. It assumes the boosting has already been done. Feed it a passive mic and the signal is so weak it sounds like silence, or a very quiet hiss.
• An active CCTV microphone (often sold as an "audio pickup") has a small amplifier inside. It needs its own power, and in return it outputs a signal strong enough for the camera.

So when you shop for a camera mic cable or a microphone, look for wording such as "active", "amplified", "pickup" or "with built-in preamp". A phone headset mic or a cheap clip-on mic for a computer is almost always passive and will not work on its own.

A note on the term camera mic adapter: an adapter that only changes the plug shape (for example a 3.5 mm jack to RCA) does not add any amplification. It is useful to make the plugs fit, but it does not turn a passive mic into an active one.

Step 3: Choose an active microphone that fits your setup

Before buying, check three things against your camera's manual and the microphone's label:

1. Power requirement. CCTV pickups typically run on low-voltage DC, sometimes the same supply type the camera uses. Read the voltage printed on the microphone and on your power adapter, and make sure they match. Do not guess.
2. Connector. Most pickups have three wires: one for power, one for ground (shared), and one for the audio signal. The signal wire often ends in an RCA plug, while the power wire connects to a DC splitter or a terminal block.
3. Where it will go. Indoor pickups are usually small and not weather-sealed. If the microphone must sit outside, choose one made for outdoor use, or mount it under cover.

Some pickups have a small sensitivity or volume adjuster. That is helpful in a noisy shop or a large room, because you can turn it down to reduce background hum.

Step 4: Wire the microphone (power off first)

Work with the power switched off. If the camera is on a ladder, a wall or a roof, have someone hold the ladder, and if any part of the wiring involves mains electricity, use a qualified electrician.

1. Unplug the camera's power supply (or switch off the PoE switch port if it is powered over the network cable).
2. Connect the microphone's signal lead to the camera's AUDIO IN. RCA to RCA where possible. If the plugs do not match, use a plug adapter of the right type.
3. Connect the microphone's ground to the ground of the power supply. On many pickups the ground is shared between power and signal, so this happens automatically through the RCA shield and the DC plug. Check the microphone's diagram.
4. Connect the microphone's power. Common ways are a DC splitter cable that feeds both the camera and the mic from one adapter, or a separate adapter for the microphone. If you share one adapter, confirm it has enough spare capacity for both devices; the label on the adapter and the mic tell you their ratings.
5. Seal outdoor joints. Bare RCA and DC joints collect water. Use a weatherproof junction box or wrap them with self-amalgamating tape, and keep the joints off the ground.
6. Keep audio wiring away from mains cables where you can. Running the mic lead alongside a power cable often adds a low hum.

Then restore power.

Step 5: Switch audio on in the app

Wiring alone may not be enough. On some models the audio setting is off by default, especially where audio is optional. Menu names vary a little by app version and model, but the path is usually similar:

1. Open the app and tap the camera.
2. Open the camera's settings (often a gear icon).
3. Look for Audio, Sound, Record audio or an entry under Recording or Video settings.
4. Turn audio on. If you see a choice between an internal and external microphone, pick external.
5. If there is an input volume or gain slider, start in the middle.
6. Save and wait a moment for the camera to apply the change.

If the camera is recorded by a separate recorder (an NVR or DVR) instead of only the app, audio usually has to be enabled for that channel on the recorder as well. Check the recorder's channel or encoding settings.

Step 6: Test live view, then a recording

Test in this order so you can tell where a problem sits:

1. Live view. Open live view and tap the speaker icon so it is not muted. Have someone talk near the microphone at normal volume.
2. A short recording. Let the camera record a minute or two with someone talking, then play it back in the app.
3. A clip on another device. If you copy clips to a computer and hear nothing, try a media player that supports many formats, such as VLC, before assuming the camera is at fault.

What each symptom usually means

What you hear	Most likely cause	What to try
Complete silence	Passive mic, mic not powered, audio off in settings, or mic plugged into AUDIO OUT	Confirm the mic is active and powered; recheck the lead label; check the app setting
Very faint sound	Low mic sensitivity, gain too low, or a long thin cable	Turn up the mic's adjuster or the app's gain; shorten the cable or move the mic closer
Constant hum or buzz	Mic cable near mains wiring, or a ground loop from two separate power supplies	Re-route the cable; try powering mic and camera from the same supply
Loud distorted sound	Gain too high, or a mic placed right next to a speaker or machine	Lower the gain; move the mic
Sound in live view but not in recordings	Recording audio is a separate setting on some models, or the recorder channel has audio off	Check recording settings in the app and on the recorder
Sound in the app but not on a computer	The computer's player cannot decode the audio track	Play the file in a player that supports more formats

If the picture and sound drift out of sync, that is usually a network or playback issue rather than the microphone. The no-sound troubleshooting guide covers that in more detail.

Where to place the microphone

Placement matters more than people expect:

• Close to the area you care about. A pickup near a counter or a door picks up voices far better than one high up in a corner of a large room.
• Away from fans, air conditioners, fridges and speakers, which can drown out speech.
• Not right beside the camera's own speaker if your camera has talk-back. This can cause echo or screeching when you use two-way audio. If talking through the camera stops working properly after you add a mic, see how to fix two-way audio.
• Under cover outdoors, angled slightly down so rain does not sit on the grille.

Recording audio: check local rules first

In many places, recording people's conversations is treated differently from recording video, and the rules can be stricter for audio. This is especially relevant in shops, offices and rental properties. Check local rules before you add a microphone, and tell people that sound is being recorded, for example with a clear sign.

In a workplace, think about whether you need sound at all. Video alone covers most security needs. Our office security camera setup plan covers where cameras should and should not point. If you later decide you only want video, turning the microphone off explains how to make sure recordings are truly silent.

When to get help

Stop and ask for help if:

• Your camera's leads are unlabelled and you cannot find a manual for the exact model.
• The microphone and camera need different power types and you are not sure how to supply both safely.
• Any part of the job involves mains wiring, working at height or drilling through outside walls. Use a qualified electrician or installer.
• You hear nothing even with a known-good active mic, correct wiring and audio enabled. The audio input on the camera may be faulty; contact the seller with the model number and a description of what you have tested.

Install or resell cameras?

Customers often ask for sound after the camera is already up. A few habits save return visits:

• Ask about audio during the survey. If the customer wants sound, choose a model with a built-in mic or an AUDIO IN lead from the start, rather than trying to add one later.
• Carry a known-good active pickup so you can tell quickly whether a silent channel is the camera, the mic or the settings.
• Label every joint in the junction box (power, mic signal, ground) for the next person who opens it.
• Mention local rules on audio recording and suggest a sign, so the customer is aware before switching sound on.

If you install or sell cameras and want to learn about the dealer program, see Yoosee business partner information.

Frequently asked questions

Can I plug any microphone into the camera's audio cable?

No. The audio input on most cameras expects an amplified, line-level signal, so it needs an active (powered) microphone. A passive mic, such as one from a headset, produces too weak a signal and usually sounds like silence.

Is an IP camera with mic better than adding an external one?

For most homes, yes, because there is nothing extra to wire, power or weatherproof. An external pickup makes sense when the camera must be high up or far from the people speaking, since the mic can then sit closer to the conversation.

How long can the microphone cable be?

It depends on the microphone and the cable quality, so check the pickup's manual for its recommended maximum. As a general guide, keep the run as short as practical and away from mains cables, because longer runs pick up more hum and lose volume.

Do I need a separate power supply for the microphone?

Not always. The mic and the camera can often share one adapter through a splitter cable, which can also help avoid hum from a ground loop. Only do this if the adapter's rating covers both devices and both need the same voltage; otherwise use a separate supply.

Will the external mic also let me talk through the camera?

No. A microphone only carries sound from the scene to you. Talking back needs a speaker, either built into the camera or connected to an AUDIO OUT lead, and two-way audio support for that model.

My camera has no audio lead. Is there any adapter that adds one?

No adapter can add an audio input the camera's hardware does not have. If you need sound, the practical option is to replace the camera with a model that has a built-in microphone or an AUDIO IN lead.