A tuning surprise

[KevinH]

I tuned one of my guitars this morning, using the ProGuitar Tuner app on my phone, played a bit then moved to a different room. The guitar sounded a little out of tune. I checked it, and sure enough some of the strings were as much as 6 cents off.

Out of curiosity I went back to where I tuned it earlier and found that it was in tune again. So then I checked 3 different rooms, while keeping the same position of the phone relative to the guitar, and the tuning was different in all of them, though the biggest difference was still 6 cents. I used an E4 tuning fork to check my phone app and sure enough it read right at 329.6 Hz.

Given the differences in how each room reflects sound waves I suppose this shouldn't be a surprise. But it was.

[why2]

Very interesting.

I can perceive different tonal qualities from a room change but I haven't noticed a tuning change.
I'm getting out the StroboPLUS!

why2

So I used the Claxton Malabar and really didn't see any change in tuning. Humidity around here is up from monsoon action (great thing!).

[nickv6]

Interesting post. Are there big differrnces in the humidity between the rooms or are you suggesting it's just the shape of the rooms? Very worthwhile trying to work out what's going on I'd say.
Nick
Oh, and how long in the next room before you tuned it again?

[jjbigfly]

Could it be that the phone tuner works with the actual sound and not the vibrations? If so, then changing rooms would change what the phone tuner is hearing. The tuners I have work with the vibrations of the instrument.
Not that’ I would know, but it sounds like it’s reasonable…..

[Rudy4]

Ceiling fans can throw off the response of a phone-based tuner. Just a thought, since I know this to be true.

I believe all phone-based tuners work with the built-in microphone. Even if they worked by contact they would still be using the phone's mic element.

[rick-slo]

Temperature changes will change tuning frequency.

[KevinH]

Originally Posted by nickv6

Interesting post. Are there big differrnces in the humidity between the rooms or are you suggesting it's just the shape of the rooms? Very worthwhile trying to work out what's going on I'd say.
Nick
Oh, and how long in the next room before you tuned it again?

No, the rooms are connected, but of very different shape. One was my den where I sit in front of large (but quiet) computer screen. The other rooms were 2 to 3x bigger in size.

Originally Posted by jjbigfly

Could it be that the phone tuner works with the actual sound and not the vibrations? If so, then changing rooms would change what the phone tuner is hearing. The tuners I have work with the vibrations of the instrument.
Not that’ I would know, but it sounds like it’s reasonable…..

Yes, I think that's what's going on. Room size/shape is really the only difference. Same RH and temp.

Originally Posted by Rudy4

Ceiling fans can throw off the response of a phone-based tuner. Just a thought, since I know this to be true.

I believe all phone-based tuners work with the built-in microphone. Even if they worked by contact they would still be using the phone's mic element.

Yes, I've fallen into the fan trap before. But no fans running in this case.

Originally Posted by rick-slo

Temperature changes will change tuning frequency.

Yeah, but the room temp should be close. They're connected rooms. No HVAC running. My hygrometers shown the RH and temp to be close. Seems like it must be proximity to walls, and the acoustic properties of the room?

I'll probably try this again to see if its repeatable.

[RussellHawaii]

I’d be curious if you get the same result with a clip-on tuner? That is, if the result is repeatable as is.

[EZYPIKINS]

Try this.

Same room. Hold neck dead level. Tune. Then raise neck, where headstock is up by your head. Retune.

Next hold neck so headstock is pointing down, level with your hip.

Tune will be different every time. Just by gravity.

The more sensitive your tuner, the more you will notice.

[RJVB]

I don't know this tuner app, but I do know accuracy can vary a lot between apps.

I use the Airyware tuner app, which I've verified to give the same results (offset in cents) as my luthier's big Peterson tuner. The paid version even has a calibration feature that allows you to tell it what "silence" sounds like where you are.

It's easy enough to rule out the tuner though. You should be able to hear a 6 ct tuning difference.