My new iPhone 6 plus is the best hand held tuner I have ever used. The response is incredibly smooth and predictable and it seems more accurate than any other hand held tuner I own or have used. The big screen on my "plus" makes it seem even more deluxe, especially when you get really close to spot on tuning and the alignment bars decelerate gracefully and come to a rest.
 
It's been a real pleasure to use, but for the past couple weeks I've been relying on it's microphone and using it in quiet settings.
 
Last night I learned about and ordered a new plug in attachment for my iPhone tuner:
 

 
I found out about it at the Peterson website and then learned that many vendors carry this part so you can purchase one easily.
 
I ordered my new plug in attachment cable last night and it will arrive on Tuesday. :-)
 
 

See now you just cost me some money. I didn't realize Peterson had a strobe tuner app. 
 
http://www.petersontuners../index.cfm?category=150

I've got the Peterson, as well. Works great. iStuff isn't all bad.

Hi Mike,
 
The TC Polytune app is also excellent.
It's smoother and easier to use than the actual pedal.

Hi Jim,
 Thanks for the heads up. Polyphonic tuning? Wow! That app is freaky deaky.
 
 :-)

And the opposite:
The HT6 polyphonic tuning pedal from Digitech works great (smooth)... but the app jumps around too much for quick tuning.   

Is there nothing these phones can't do? Scary.

 
I fail to see the need to use one's phone, especially a 700$ one, for a tuner.
 
Than 1/8" connector sure looks flimsy and can it even be repaired ?
Where do you put the phone when you're tuning ?  Balance it on your knee ?
 
I'd go with a tuner pedal or a vst tuner.  Just about anything but a phone.
 
 
 

I've got several other hardware tuners, and I have some tuner apps in the DAW.
 
This is my favorite tuner. I just love using it.
 
I've wanted a real Peterson stroboscope for a long time, but this little phone rig seems to be working great.
 
 
 
 
I am curious about the cable, and would have simply wired my own up but I wasn't clear on how they get from 1/4" TS female to the 1/8" TRRS male.
 
It also occurred to me that it may have an attenuation pad in the head of the cable to protect the phones input.
 
After I have a clear idea of what is going on I am going to wire up a nice flexible cable with a 1/4" male TS and the 1/8" TRRS.

mike_mccue
After I have a clear idea of what is going on I am going to wire up a nice flexible cable with a 1/4" male TS and the 1/8" TRRS.

Soldering a 1/8" trrs must be a lot of fun