How to Use a Professional Microphone with Singing Apps Like Smule
If you enjoy singing on Smule and want to take your recording quality to the next level, this guide walks through exactly how to connect a professional XLR microphone to your phone. The setup costs a little over $100 and works with iOS and Android.
Choosing a Microphone
This guide assumes you've already chosen a microphone. If not, the Audio-Technica AT2020 is a strong starting point — it delivers excellent quality at a reasonable price and is widely used for home vocal recording.
You may also want to consider a pop filter to reduce plosive sounds (the hard "p" and "b" sounds that clip mics), and some basic acoustic treatment to reduce room noise and echo. Even something as simple as recording in a closet full of clothes makes a significant difference — often more than any gear upgrade.
The Audio Interface
A professional XLR microphone can't plug directly into a phone — you need an audio interface to convert the analog signal to digital. One of the most cost-effective options for a single vocalist is the Focusrite Scarlett Solo 3rd Gen, which retails for a little over $100.
The Scarlett Solo has two inputs: one XLR port for a microphone (or other device) and one 6.35mm (¼″) port for an instrument. For a solo singer just connecting a mic, this is more than enough. Larger variants like the Scarlett 18i8 exist for bigger productions, but they're overkill here.
Each input has its own level knob for independent adjustment. The XLR port also provides 48V phantom power, which condenser mics like the AT2020 require to operate. Note that phantom power won't pass through external devices like effects pedals — so if you're adding anything between the mic and the interface, confirm that device can also supply 48V.
Connecting to Your Phone
The Scarlett Solo connects to your phone via USB-C. Depending on your device:
Newer Android phones — use a USB-C to USB-C cable directly.
iPhones/iPads — use a USB-C to Lightning cable.
Older Android phones — use the included USB-C to USB-A cable with a USB-OTG adapter.
Once connected, your phone's audio will route through the Scarlett's built-in headphone jack. Depending on your headphones, you may need a 6.35mm (¼″) to 3.5mm (⅛″) adapter.
Monitoring While You Sing
With the Scarlett plugged in and headphones connected, press the Direct Monitor button on the interface. This routes your mic audio directly to your headphones in real time — so you can hear both your voice and the backing track simultaneously as you record.
You'll likely need to balance three levels: the input gain knob for the mic, the volume on your phone, and the output knob on the Scarlett. Take a few minutes to dial these in before you start recording. Once you find a good balance, it'll hold across sessions.
When you're done recording, press Direct Monitor again to remove the live mic from your headphone mix. Then you can listen back to the finished take cleanly.
Common Issues
The "Vocal Match" slider in Smule will sit very far to the right — because audio is arriving via fast direct USB rather than through the phone's internal mic path. Smule's auto-detection usually gets close, but fine-tune manually for best sync.
Your vocal will be noticeably louder than with a standard wired headphone mic. You'll likely need to lower the vocal volume in Smule to match the song. This is a better problem than being too quiet — just dial it back.
If you notice distortion when singing loudly, turn the input knob counter-clockwise to reduce the signal level going to the phone. A little goes a long way.
If your device can't deliver enough power, try a powered USB hub between the phone and the interface, or a cable that simultaneously draws power from a wall adapter.
Quick Alternative: iRig Pre 2
If the Scarlett setup feels like more than you need right now, the iRig Pre 2 from IK Multimedia is a simpler analog option.
iRig Pre 2
Smaller and cheaper than the Scarlett. Runs on a 9V battery. Plugs directly into your phone's headphone jack or Lightning port. Audio quality is a step below the Scarlett interface, but it's very reliable with Smule on iOS and essentially plug-and-play — no drivers, no power issues.
Final Notes
Once your setup is dialed in, it works with any singing app — not just Smule. The Scarlett Solo also doubles as a basic home recording interface for other uses: it has left and right line outputs so you can connect to a speaker system, soundboard, or DAW if needed.
The total investment is modest for what you get: a genuinely professional vocal signal path, running through a phone app, with real-time pitch correction and effects layered on top. For serious Smule singers, it's hard to beat.