Can you use a 3.5 mm jack as a mic?
What is a 3.5 mm jack?
A 3.5 mm jack, also known as a headphone jack or aux jack, is a standard audio connector used in many consumer electronics devices. The name refers to the size of the connector, which is 3.5 mm in diameter. 3.5 mm jacks are commonly used for analog audio signals like headphones, speakers, microphones, or line-level connections. They have been a standard feature of portable devices like smartphones, tablets, laptops, handheld gaming systems, and more for connecting headphones or external speakers.
The 3.5 mm connector has been widely adopted as a standard and replaced larger audio connectors because of its compact size. Despite recent trends of removing the 3.5 mm jack on some smartphones, it remains extremely common. When people refer to a device having a headphone jack, aux jack, or 3.5 mm jack, they are talking about this nearly universal audio port.
Can a 3.5 mm jack be used as a microphone?
Yes, a standard 3.5 mm audio jack can be used as a microphone input with the right adapter. The 3.5 mm jack is capable of carrying both input and output audio signals. This is because it actually has three connection points – left audio, right audio, and ground. Some 3.5 mm jacks also include a fourth connection point for a microphone.
To use a 3.5 mm jack for a microphone input, you need an adapter that supports TRRS – Tip, Ring 1, Ring 2, Sleeve. The tip connection is used for left audio out, ring 1 is right audio out, ring 2 is used for the microphone input, and the sleeve is ground. With this wiring, a TRRS adapter allows the mic and headphone signals to share the jack.
As explained in this Headphonesty article, many modern smartphones and audio devices support TRRS on their 3.5mm jacks, so a TRRS adapter can enable mic input. However, you need to verify compatibility to ensure proper operation.
Adapter needed
To use a 3.5 mm jack as a microphone, you’ll need a TRS (tip, ring, sleeve) to TRRS (tip, ring, ring, sleeve) adapter. This is because standard 3.5 mm headphone jacks use the TRS wiring configuration, which contains separate left and right audio channels but no microphone input. TRRS wiring adds in a third ring contact to enable mono microphone input in addition to the stereo headphone output.
The main difference between TRS and TRRS is that TRS only carries stereo audio output while TRRS allows a mic input over the same 3.5mm plug. So to convert your TRS headphone jack into a usable microphone input, you need a simple adapter that bridges the gap in wiring configurations.
TRRS wiring
TRRS stands for Tip, Ring, Ring, Sleeve, referring to the four segments of a 3.5mm audio jack. TRRS wiring allows a single 3.5mm jack to integrate both headphone and microphone functionalities. The wiring is as follows:
- Tip – Left audio channel
- Ring 1 – Right audio channel
- Ring 2 – Ground
- Sleeve – Microphone
This wiring scheme allows stereo audio to be output through the headphone speakers, while also accepting mono input from a microphone. The extra segment compared to traditional TRS jacks is what enables the combined headphone/microphone functionality. To utilize a 3.5mm jack as a microphone input, it needs to follow the TRRS scheme.
For more details on TRRS wiring, refer to this helpful guide: https://www.circuitbasics.com/how-to-hack-a-headphone-jack/
Compatible Devices
Many devices have built-in compatibility with using a 3.5 mm jack as a microphone, including:
- Smartphones – Most modern smartphones include a combo audio jack that supports TRRS connections for headsets with an integrated microphone.
- Tablets – Tablets with a 3.5mm combo jack can also utilize TRRS adapters and headsets as a microphone solution.
- Laptops – Many laptops have a combo audio jack capable of TRRS input and can function as a mic with the proper adapter or headset.
- Gaming Controllers – Gaming controllers and headsets that connect via 3.5mm often rely on TRRS standards for their integrated mics.
For devices without native TRRS support, an adapter can add compatibility. Overall, the vast majority of modern consumer devices are designed to support audio input via a TRRS 3.5mm connection out of the box.
Microphone quality
Using a 3.5 mm jack as a microphone will result in lower quality audio recordings compared to professional XLR or USB microphones. This is because 3.5 mm jacks and the supporting audio components in consumer devices are designed primarily for headphone output rather than high-fidelity input [1]. The microphone quality you can achieve depends on the audio components built into the specific device.
Most smartphones, laptops, and audio interfaces contain basic microphone preamps and analog-to-digital converters designed for voice calls and simple recording. This results in higher noise, less gain, poorer frequency response, and lower bitrates than professional microphones and preamps. However, quality can vary significantly depending on the device. For example, newer smartphones tend to have improved audio components compared to older laptops.
For casual voice calls, live streaming, and basic recordings, using a 3.5 mm jack as a mic into a modern smartphone produces usable results. But for professional broadcasting, podcasting, or music recording, an XLR or USB microphone is recommended for better quality. Expect background noise, echo, clipping, and thin frequency response when using a basic 3.5 mm mic jack.
Using a Headset
One of the easiest ways to use a 3.5mm jack as a microphone is by using a headset that has a built-in mic. Many gaming headsets and mobile headsets include an integrated microphone along with the headphone speakers. These headsets are designed to plug directly into a 3.5mm audio jack and provide both input and output capabilities.
Headsets with a built-in mic allow the 3.5mm jack to function seamlessly as a microphone and headphone connector. They have all the necessary wiring and components inside to enable the microphone and headphone features over a single 3.5mm plug. This makes headsets with integrated mics a plug-and-play solution for using a 3.5mm port as a mic.
The main benefit of using a headset is that it enables simultaneous microphone and headphone usage through the one 3.5mm jack. The headset handles splitting the signals so that the mic input and headphone output can work at the same time over the single interface. This avoids the need for any kind of adapter or splitter accessory.
Overall, a headset with an integrated mic is one of the simplest ways to utilize a 3.5mm audio port for both microphone and headphone connectivity. The all-in-one design makes 3.5mm headset mics a convenient option requiring no additional hardware or configuration to function as a microphone and headphones.[1]
Sources:
[1] https://www.ebay.com/itm/335088628879
TRRS Adapter
To use a 3.5mm headphone jack as a microphone you’ll need a TRRS adapter. This converts the microphone input from the headphones into a standard TRRS output that can be used for recording audio.
When buying a TRRS adapter it is important to match the headphone pinout to the adapter. There are two standards, OMTP and CTIA, which use different pinouts for the headphones. An OMTP adapter will not work properly with CTIA headphones and vice versa. For example, according to Crutchfield, OMTP headphones have mic and ground separated while CTIA has mic and ground together.
Before purchasing a TRRS adapter, check whether your headphones follow the OMTP or CTIA standard. The adapter must match the headphone pin configuration for the microphone input to work properly.
Troubleshooting
If you are having issues using a 3.5 mm jack as a microphone, here are some troubleshooting tips:
First, check the adapter wiring to make sure it supports TRRS and has the correct pinout for microphone input. Some adapters may only support stereo audio output and not mic input, so verify it is wired for mic functionality. Refer to the adapter documentation to confirm the pin assignments (source).
Next, ensure your device is compatible with using the 3.5 mm jack for a microphone input. Some smartphones, tablets, and laptops may not support this configuration, so check your device specifications. If the mic input is not supported, you may need to use a USB microphone instead (source).
Finally, if you have a combination headphone/mic port, try disabling the headphone mic function in your sound control panel/settings if it is interfering with recognizing your 3.5 mm mic input. This prevents the device from defaulting to the built-in mic.
Conclusion
In summary, a 3.5 mm jack can be used as a microphone in many cases by using a TRRS adapter. The key points are:
- 3.5 mm jacks support 4 conductor TRRS wiring that allows audio input and output.
- With a TRRS adapter, a 3.5 mm port can function as a microphone input.
- Compatibility depends on hardware support for TRRS and mic input on the specific device.
- Quality may not match a dedicated external mic but provides a convenient option.
- Headsets with an inline mic use TRRS for both mic and headphone audio.
Overall, while a 3.5 mm jack is designed mainly for audio out, with the right wiring it can provide a handy microphone input for many devices and users.