I'm trying to figure out how to create a circuit that connects an external audio source, like my electric guitar, to the iPhone's external microphone input. I've searched online and mostly found expensive mixing consoles without any detailed specs. I have some experience with building audio circuits and I'm specifically looking for what the iPhone requires in terms of input levels and impedance to recognize a microphone is plugged in. I already own a lightning to headphone/microphone adapter and I'm aware that iPhones can be quite picky about what's connected. For example, if I'm plugging something into the headphone jack, it needs to have an impedance of around 32 ohms for the phone to recognize it as headphones. My goal is to send a signal from my guitar, which outputs roughly 60mV, into the iPhone so I can use a practice app without disturbing anyone. I know newer iPhones have good input frequency response, but I'm not aiming for professional quality, just enough to practice silently. If anyone can share the specifics of what signals I need to send through the mic input, I'd really appreciate it!
3 Answers
I just posted my own DIY solution for connecting a guitar to the iPhone using a simple circuit. Unfortunately, I can't share it here due to image limits, but you can check it out in the DIY Electronic Projects community [here](https://www.reddit.com/r/DIYElectronicProjects/comments/1o81sug/diy_guitar_to_iphone_interface_via_mic_input_with/). It might help you out!
The original iRig from 2010 did something similar, but it's a bit outdated now. However, there are cheaper alternatives available like TRRS splitters with a quarter-inch input for guitars. Just be cautious about sound feedback if you're using them for live performance. For better quality, you should consider getting a USB audio interface designed for guitars, especially those that work with iOS, which can connect easily if you have the right adapter.
Definitely understand the desire to keep costs down. While they can help for practice, sometimes combining signals can get tricky. Testing your DIY setup first sounds like a smart move before diving into a pre-made solution.
You might want to check out devices like the Square payment card readers that used to plug into the iPhone's 3.5mm audio jack. They had specific electrical setups for audio input, though they might not help much with DIY specs since they're proprietary. But generally, you'd need the right electrical conditions to trigger the iPhone's mic input to recognize audio signals. What you're aiming to do is definitely feasible if you can get your circuit tuned to those specs!
I see what you're saying, but I’m really after the actual specs for the electrical setup to build my own circuit. I know the basics about the lightning port handling more than just audio; it can switch between outputs based on what's connected. What I need to know is the specific conditions to apply to the microphone wires so the iPhone recognizes that there's a mic plugged in.
Thanks for the link! I might grab one of those cheap interfaces just to see how they work inside. My main goal right now is to practice with my iPhone along with a metronome app. Do you know if those metronome apps can output through the iRig along with the guitar signal? I'm trying to avoid shelling out for something too expensive for just practicing.