Flawed Intonation Options

[bassrun]

Based upon my own positive experience with the StroboFlip as well as the enthusiastic reviews that I read at the iTunes app store--but in spite of some conflicting reports on the Unofficial Martin Guitar Forum (www.theunofficialmartinguitarforum.yuku.com)--I purchased and installed iStroboSoft. Unfortunately, I'm experiencing the same problem that I read about on the UMGF.

Specifically, when I carefully tune each string with iStroboSoft, the result is a poorly tuned guitar. On the other hand, using either a standard electronic tuner or the free iPhone app "Tuner," the result is a perfectly tuned guitar. The problem is with the 4th and 6th (D and low E) strings--the other 4 strings are tuned properly by iStroboSoft.

Anecdotal reports on the UMGF (http://theunofficialmartinguitarforum.yuku.com/topic/83559/master/1/?page=2) indicate that this intonation problem can be cured by subsequent installation of Guitar ToolKit. But I sure as heck don't want to pay $10 for GTK just to fix iStroboSoft.

Are you aware of this problem? Has anyone discovered a no-cost fix?

--John

[Marshall Johns]

John,

Thank you for your contact.

Are you using the Peterson adaptor cable or the built-in mic? Is this an iPhone 3G or 3Gs? iPod?

The installation of GTK does not seem to be a valid remedy for this. Installing one app to fix another does not make sense aside from the fact that it may prompt for a rebooting of the device. Rebooting the device after installation of iStroboSoft is recommended and explained in the App Store description. This may be the fix for other users if they did not originally power cycle their devices.

If your device is a 3Gs, this may be the issue. We have recently identified that the 3Gs adds a high-pass filter on the built-in mic that carries over to the line/mic-in connector. The filter is set steeper than on the 3G at approximately 250Hz. The strings you mentioned are located under this frequency and may be problematic to tune.

The noise filter and boost may improve your readings. If you are using an adaptor cable, plug in the adaptor cable WITHOUT plugging in your guitar or mic, run the noise filter, then connect your instrument/mic.

For 3Gs users, we are looking to address the issue of the high-pass filter, as many other audio measurement applications are at this time, and will release an update when possible.

[bassrun]

Marshall--

Thanks for your reply. I just left you a phone message, not realizing that you'd already replied to me online.

I'm using a 3Gs without an adapter cable--just the built-in mic. And yes, I agree that installation of GTK sounds like a dubious remedy!

When you recommend rebooting, you're just talking about powering off the iPhone, or is there some other more fundamental rebooting routine? I did power off my iPhone, and it didn't help. I also tried toggling both the noise filter and the boost setting, but with no effect.

Interestingly, the free iPhone app "Trace Tuner" (which is not nearly as sophisticated as iStroboSoft) registers the pitch of my strings perfectly, so I'm surprised that iStroboSoft would have problems with the high-pass filter. If the problem is with the iPhone's built-in mic, does this really make sense?

Is there any thing special about the Peterson adapter cable? Is it anything more than a 1/4" to 1/8" adapter?

--John