I was lucky enough to get my hands on a preview copy of TabToolkit, the latest in creative musical software from Agile Partners.

I’ve been a huge fan of their first release, GuitarToolkit, which is a fantastic, must-have app for guitarists. It includes a tuner, a metronome, a chord book and a scale chart for just about every variation you could think of on a guitar (it also supports bass guitar and ukulele now, too).

TabToolkit is an incredibly ingenious app which can pull guitar tablature files from your favorite tab website, format them specifically for the iPhone or iPod Touch and then, depending on the type of the tab, allow you to play along with it as it shows you proper fingerings for each chord. TabToolkit supports Power Tab and Guitar Pro files as well which will show more than the simple text tab pictured above.

According to Agile Partners’ press release, “TabToolkit has a built-in synthesis engine to let you hear the music for your score. The ability to hear an instrument play notes is a huge help in learning new music. If things are moving a little too fast, you can slow the tempo down to a crawl and learn tricky parts one note at a time.”

Aside from a metronome that plays along side of you and a variety of instruments to choose from for note reference, there’s a built-in web browser that allows users to navigate to their favorite tablature websites, look up the tab that they want and after it recognizes the tab, TabToolkit will download it and store in the tab library. I’ve been using this app non-stop for days.

TabToolkit is an incredible companion app to go along with GuitarToolkit and frankly, any guitarist should own both. They’re beautifully designed apps created by active musicians who just happened to be very skilled in Objective-C programming too.

TabToolkit retails for $9.99 and is available in the App Store now.

Interview: Jack Ivers of Agile Partners, makers of the iPhone app GuitarToolkit

It’s been quite a while since the last update, what have you guys been working on for GuitarToolkit?

Yes, it has been a while … we’ve been very busy with two other music apps - Star6, which is a sample-based musical instrument, and another app, a companion to GuitarToolkit, which has been submitted but hasn’t yet reached the store. But we’ve also been working on GuitarToolkit 1.3, which is our biggest update yet, and that’s saying something, because we’ve done massive updates in previous GuitarToolkit releases. This is definitely the biggest.

What are the features you’re most excited to release in the 1.3 update?

First of all, some huge changes relating to chords.

Number one has to be the chord library. We’ve increased the chord library from a bit over 1,500 chords in the prior release to - get this - 500,983 chords in release 1.3. We’ve done this by adding new chord types, providing chords for all alternate tunings - one of the most consistent requests we’ve had from customers - and adding four new instruments with chords: banjo, mandolin, ukulele, and 6-string bass.

We’ve also added a chord finder:  you can simply touch the notes on the fretboard that make up the chord, and GuitarToolkit tells you what the chord is! This is a lot of fun and a great way to learn what those great-sounding chords you’ve been playing actually are.

We added two new chord display modes: in addition to showing finger positions, you can now see notes and intervals.  So, let’s say you’re looking at a C 7 chord, in notes view, you’d see C, E, G, and B♭on the fretboard, in intervals view, you’d see 1, 3, 5, and ♭7. This seems small but in practice it is amazingly useful, a great way to learn what notes actually make up different types of chords.

Second, some important changes to the tuner.

We now allow you to change the reference pitch - the default is A=440 tuning, but you can now change this up or down.  A lot of pro musicians, especially classical musicians, need this capability, because orchestras often tune to a different reference pitch such as Philharmonic (A=433).

We’ve added a high-contrast mode for the tuner, which is easier to read from a distance or for those of us who are farsighted. Here’s a screenshot:

Third, the metronome (although it looks the same to the user) has been completely rewritten using a different technology so it is precisely on the beat, all the time.  It also runs in background while you’re using other GuitarToolkit features and continues to operate, precisely on beat, with the device locked.

Finally - take a close look at the screenshot - we’ve internationalized GuitarToolkit for French, German, Spanish, Italian, and Japanese.

Will you be updating GuitarToolkit Lite also, for iPod Touch users?

Yes, we will continue to update GuitarToolkit Lite.  It’s important that people understand, though, that from the 2G iPod touch onwards, the touch supports tuning using the earbud mic, so for most people, it’s definitely better to buy GuitarToolkit rather than Lite.

If so, how does that update differ from the update for the full version?

It will be everything but the tuner. The 1.3 release for Lite should happen a few weeks following the GuitarToolkit release.

How has the development process been creating this application that guitar players call “priceless?”

Pretty much everyone on the GuitarToolkit development team is a guitar / music enthusiast, which helps a lot. Our customers have been fantastic, with great suggestions and an amazing willingness to post comments about GuitarToolkit on the App Store and on Twitter. From an iPhone development perspective, we try to create apps that combine an amazing user experience - high “awesomeness factor” - with solving really hard technical problems.

Specifically in the most recent update that you plan to submit to Apple tomorrow, have there been any obstacles that you’ve had to overcome in designing or programming the application?

There were two really touch technical challenges with GuitarToolkit. One was embedding music theory into the app, so that we could “understand” guitar chords - generate them, look them up. And how do you determine a good chord? Or determine which chord is the best fit when you’re doing a lookup.  A challenge to say the least.

Getting the metronome to operate absolutely precisely was also a big challenge, one where the normal approaches which involve an asynchronous event model just don’t work.

Hard problems are fun, though!  We thrive on them.

How many people does Agile Partners have working on GuitarToolkit?

Six people with varying degrees of involvement.

Moving forward past version 1.3, can you talk about a feature or two that users can expect to see in the future? Things you’d like to do or add to the application?

We’re already thinking about release 1.4. Improving scales is high on the list.  And more good things in the works for tuner and chords.

The biggest new thing for GuitarToolkit customers, though, beyond 1.3, is going to be the companion product. We’re not talking about it until we get App Store approval but as soon as we do, we think GuitarToolkit customers will be very jazzed.