We’ve been considering this issue since as far back as 2008: GuitarToolkit customers have long been asking for a way to tune their electric guitars and basses without needing to power up an amp. We looked into what it would take and started building prototypes in 2009. At around the same time, the lightbulb went off: “Wow, if we could connect an electric guitar as input to an iPhone, and still have headphone audio coming out, we could do some really interesting things …” and this eventually led to our forthcoming AmpKit app.

Today, after a full 10 generations of prototypes, we’re thrilled to be collaborating with Peavey Electronics on the commercial realization of our explorations: AmpKit LiNK, a guitar and bass interface that, paired with AmpKit, bring full-scale amp and effects simulation to iPhone, iPod touch, and iPad users. (AmpKit LiNK is available for preorder here.)

OK, so let’s look at the challenges of interfacing a guitar through the iPhone’s headset connection. One *could* simply rig up an adapter cable that would connect a guitar signal to the iPhone headset input, and a headphone jack to the iPhone headphone output; our first prototypes did just this, and there’s even a commercial product made this way. But you would encounter a number of problems.

1- The iPhone will (possibly intermittently) fail to detect that an audio device has been plugged in to the headset jack. The iPhone is looking for the electrical signature of its earbud headset, which includes an electret microphone. A guitar signal directly connected to the mic input is very different electrically; in our experience, a directly-connected guitar signal will “kind of work sometimes,” which can be a highly frustrating experience.

2- The incoming guitar signal will suffer severe attenuation of its high frequencies, resulting in an awful, muddy sound. This is again due to the different electrical characteristics of the guitar signal versus the electret microphone the iPhone expects.

3- You’ll get really nasty feedback if you try to use headphones with a high-gain guitar amp simulation. The issue is that, in the cable between the iPhone and the interface, the faint, low-current guitar signal runs right alongside the comparatively high-current headphone signal, using a common ground. The result is that the outgoing headphone signal bleeds onto the incoming microphone signal, a phenomenon known as crosstalk. Now, if you happen to be simulating an amplifier on your iPhone, especially a high-gain amp like a Peavey ValveKing® or 6505® Plus, this crosstalk turns into the ugly screech of feedback.

Over the course of our 10 prototypes, we grappled with each of these problems in turn. Here’s how we solved them in the AmpKit LiNK interface:

#1: The failure-to-detect problem requires a bit of circuitry such that the iPhone sees the electrical characteristics it expects with the earbud headset’s electret mic. Result: immediate and consistent detection of the connected interface by the iPhone OS.

#2: The muddy sound issue involves a more significant set of circuitry, which transforms the guitar signal such that it has the signal characteristics of an electret mic to the iPhone, while at the same time preserving the full frequency spectrum of the guitar signal. The result: a very nice, rich guitar signal which sounds great when run through an amp simulator.

#3: The toughest nut to crack was the feedback issue. We found that using a well-shielded cable between the interface and the iPhone was not by itself enough. Instead, we had to tackle the heart of the problem: the high current levels needed to drive headphones. We incorporated a tiny but powerful headphone amplifier inside the AmpKit LiNK interface itself, which enabled a radical reduction in the current flowing between the iPhone and the LiNK. Between great cable shielding and the current-reducing benefits of moving the headphone amp inside the interface, feedback on high-gain amps is virtually eliminated. You can still cause feedback if you crank a super high-gain amp up to max volume, and do the same with your iPhone hardware volume control. But this is actually fairly realistic: a real amp would have feedback under similar conditions.

AmpKit LiNK is powered by two AAA batteries. Buyers of guitar interfaces should bear in mind that, if the headset guitar interface you’re considering isn’t powered (with batteries or an external power supply), you’re almost certain to have feedback problems when simulating high-gain amplification over headphones.

Also note — anyone who owns an iPad should consider cable length. AmpKit LiNK’s cable is long enough to connect to a docked iPad with the LiNK laying flat on the table. A shorter cable would leave the interface dangling off the side of the iPad, which is likely to result in an iPad crash of the physical variety.

Stay tuned to this blog as well as @AmpKit on Twitter for news on AmpKit and AmpKit LiNK. You can also send us your questions about AmpKit or AmpKit LiNK here.

When Apple announced in April that WWDC 2010 would take place June 7-11 at the Moscone Center in San Francisco, we immediately saw it as a must-attend event for Agile Partners. With the opportunity to learn more about the latest advancements in iOS technologies, take advantage of hands-on labs, and benefit from one-to-one interactions with Apple engineers, we knew WWDC 2010 would be an invaluable experience for our team as we continue to develop innovative applications for iPad, iPhone and iPod touch.

We kicked off our visit to northern California with a weekend get-together at Yosemite. The breathtaking views and tranquil trails (with an unexpected abundance of snow still on the ground) made Yosemite the perfect way to charge up for WWDC. To top it off, the talented chefs among the members of our team made sure everyone was well nourished with some incredibly tasty meals!

After driving from Yosemite back to San Francisco, our participation in WWDC started at 6:00 a.m. on Monday, June 7 as we lined up to attend Apple CEO Steve Jobs’ keynote address. The keynote address was filled with exciting announcements that culminated with the introduction of the new iPhone 4. Then, along with 5000 developers from around the world, we started digging into a wide variety of technical sessions and hands-on labs led by Apple engineers. Our team had come prepared with several questions related to our on-going projects and it was great to discuss them one-on-one with some of the 1000 Apple engineers attending WWDC.

The week was also packed with special events including awesome lunchtime presentations by speakers from Pixar, NASA and CNN. Evening activities included the perennially entertaining “Stump the Experts” Apple trivia event (hosted by some of the most knowledgeable and colorful Apple engineers you’ll ever meet) and the WWDC Bash at Yerba Buena Gardens with surprise musical guest, OK Go.

For our team, the highlight of the week occurred on Tuesday evening when Agile Partners was honored with a 2010 Apple Design Award for our TabToolkit for iPad app. We shared the stage with eight other developers whose applications also demonstrated technical excellence, innovation, superior technology adoption, high performance and outstanding design in the eyes of the Apple judges. It was a proud and humbling moment that inspired all of us at Agile Partners to keep working hard at continuously improving our craft.

We’re not a group that rests on our laurels — by now, we’ve all returned safely home and are preparing for some exciting days and weeks ahead. We’re at the beginning of Agile Partners’ most prolific period of product launches yet, with new products around the corner that we believe will delight our customers. Armed and energized by what we learned and experienced during the week of WWDC 2010, we’re ready to create many more memorable moments. Stay tuned!

What is it that got me thinking about developing an app like Second Opinion?  Focus groups.  You know, the kind where someone is paid to interact with or critique someone else’s work.  These studies can be great, providing multiple, anonymous and–most importantly–unbiased data points from unrelated 3rd parties.  The kind of responses you can’t get get as easily from co-workers, employees, or consultants; where politics cast shade, even when there’s the best of intentions.

Having designed and participated in a number of these studies, one “gotcha” is–because for the participant, this is not an anonymous experience–participants sometimes feel social pressure to answer a particular way. To seem smarter, for instance.  A common focus group observer “trick” is to “watch what they do, not just listen to what they say,” to compensate for this effect.   Remove all relationships between the “asker”, “answerer” & “moderator”, and the truth finds its way to the surface more easily: the model behind Second Opinion.

So, let’s make it personal–I have questions. Usually it’s about something outside of my areas of expertise (I’m better with power tools than picking outfits; I can critique the heck out of a film, but won’t know if the wine I choose will offend my vinofile friends).   I wanted my own focus group … and Second Opinion became my tool for everyday crowdsourcing.   The wisdom of the crowd provides the “real answer” (i.e., what is commonly perceived to be true) in a way that friends and experts–by their very nature–may not.

And, while Second Opinion can be a really useful tool for getting others’ opinions  in a crowdsourcing sense, we learned something else about it: it is an absolute blast to use!  Both answering questions and asking questions is addictive fun.  We’ve put together a few videos to show you just how much fun:

We’re very excited about the Second Opinion launch, and are curious to see what people will ask–and learn.  Why not give it a whirl: download Second Opinion from the App Store (free, with optional in-app purchases).

Far more advanced than the basic sheet music viewers that simply display PDF or image files, TabToolkit is the only app that can smoothly render entire pages of crisp, engraved music in standard or tablature notation, on-the-fly.  You can see TabToolkit for iPad in action in this YouTube video.

We redesigned TabToolkit specifically for iPad to take full advantage of the unique features of the revolutionary device — the large display, Multi-Touch interface and incredible speed. It’s amazing how smoothly you can scroll through music with TabToolkit on iPad or jump to any point of a song by simply tapping or dragging the music on the screen. We think musicians will really enjoy viewing crisp, sharp music notation on the high resolution iPad screen.

Already one of the highest-rated music apps for iPhone, TabToolkit also enables users to listen to and control the audio of individual instrument tracks. Being able to control the audio of individual tracks makes it really fun to practice music with TabToolkit. For example, you can mute the guitar part of a song you’re learning while being guided by the bass, keyboard and drum parts playing in the background. It’s like you’re playing along with an entire band.

While other guitar tablature apps available for iPad and iPhone display only text tabs, TabToolkit fully supports “rich tabs” that include multiple instruments and the ability to hear an entire song performed. Similarly, while a few sheet music apps have appeared, these simply scroll static images or PDF pages. Because TabToolkit understands the underlying music, it accurately renders music on-the-fly in any notation, page size and orientation. TabToolkit also simultaneously renders perfectly synched multi-track audio for the song, including effects like guitar bends and slides.

TabToolkit supports text, PDF, Power Tab and Guitar Pro file formats (Power Tab and Guitar Pro files are required to experience TabToolkit’s full visual and audio capabilities). The app also has easy-to-use file upload and download features, enabling users to take their music with them wherever they go.

TabToolkit for iPad is already getting a lot of attention, particularly on Twitter. For example, @jimsylee tweeted “TabToolkit for iPad is looking veryyy nice”, @ayapejian said “TabToolkit looks great on the iPad, time to throw out all my printed guitar tabs – very happy!” and @gbevin said “TabToolkit for iPad looks mindblowing!!”  And the folks over at Mac|Life have already posted this TabToolkit for iPad article.

We’re proud that we’ve successfully tackled many tough challenges with TabToolkit, but what’s most important is that our customers enjoy our apps, find them useful and provide feedback to help us continuously improve them.  That’s Agile Partners’ commitment and what we’re focused on.

Jumping between samples is a core activity when you’re jamming out with Star6.  In release 1.0, you had to hit the sample button at exactly the right instant to keep your music “on the beat” … tough to do, even for experienced DJs. In Star6 1.1, jumping between samples is automatically quantized. You simply select what beat interval you want to quantize on, from 1/16th of a beat up to 4 beats. Then when you jump from one sample to another, Star6 automatically delays the jump so that your sound stays lined up on the beat interval you selected.

Besides keeping you lined up on the beat, quantizing also makes it possible to easily alternate between two samples, playing, for example, 6 beats from sample A followed by 2 beats from sample B, and back again. For me, this one feature makes Star6 1.1 a huge improvement.

Another big win in 1.1 is a raft of BPM-related changes. First of all, we’ve put the BPM control right on the main process screen. This control works in three different modes. First, you can touch the + or – buttons to move up or down a single beat at a time. Next, if you touch and hold, you get “alarm clock mode” where the BPM moves up or down faster the longer you hold. And finally, we’ve added a very nice scrubbing mode: if you touch and hold the BPM button, then move up or down, BPM follows that movement. So you can move from 120 BPM to 303 BPM in a split second by moving your finger up an inch — fun!

Also new on BPM is the ability to control whether pitch varies with the BPM change. Previously Star6 always used granular synth magic to keep the pitch the same, but in 1.1 you can toggle it so pitch varies up and down with the BPM. This can produce some great effects (think James Brown as fast chipmunk) but also causes less distortion when you modify the BPM on certain types of music. For example, if you’re working with the ambient loops from FM3’s Buddha Machine, BPM changes work much better in “vary pitch” mode.

Previously, Star6 would force all samples within a session to run at the same BPM. In Star6 1.1, you can now vary the BPM for each sample. This is helpful when you’re working with samples that are less beat-driven than the typical club / dance music — again the Buddha Machine samples come to mind. And finally, we’ve added a tap-to-BPM bar on the options screen, so you can easily match speeds with the music you’re listening to.

One more notable change to Star6’s control interface is around the reset button. Star6 has always had reset, which returns the six granular synth settings back to their starting (neutral) position. In 1.1, the reset button has been expanded to also reset effects and reversing; so if you have a sample playing with synth effects plus DSP effects plus running in reverse, a single tap of reset puts everything back to neutral. What’s even more powerful in 1.1 is that, if you tap reset again, it “un-resets”: that is, all those processes and effects you just turned off are turned back on in a single click. This makes some really amazing toggles possible, from wildly crunched to original sample, back and forth, just by toggling reset.

We’ve added support for downloading and installing entire sample packs in a single click, via Mobile Safari or from within Star6’s News area. We did this by registering a custom protocol, star6://, when the app installs. If you then click on a star6:// link within Mobile Safari, it automatically loads Star6, downloads the sample pack, and creates a new session for those samples. The format of a sample pack isn’t complex, just a zip file with the samples and some optional metadata, so you can publish your own star6:// downloads if you choose to.

You’ll notice a fairly significant change to Star6’s look and feel in 1.1. We had a chance to sit down and walk through Star6 with Apple’s Eric Hope, an iPhone User Experience Evangelist, at the recent Tech Talk in Seattle. Eric enjoyed Star6’s rather unique and non-standard styling and colors, but suggested a more rounded, 3D look. We’ve taken Eric’s advice and think you’ll like the results. We’ve also cleaned up many other aspects of the UI and UX, particularly the session listing screen.

All in all, in our most humble opinion, Star6 1.1 is twice as much fun! Let us know what you think.

Less than a month after their launch in the iTunes App Store, the  Merck Manual apps are already proving to be convenient resources valued by healthcare professionals and consumers on the go. Both apps have received excellent reviews and are among the Top Paid Apps in the medical category.

Customer comments and reviews for the Professional Edition (App Store link) have come from a variety of sources. Rickkus wrote in the Australia App Store, “Lots of cross references and they are all linked. Just click the link and you are there. Much more information than similar medical apps I have bought, and less than half their price.” In the US App Store, Nursemedic99 commented, “If you like the Merck Manual, you’ll definitely like this app. I use it on a regular basis. It’s well worth the $30 to have the Merck with you at all times.” Before purchasing the app, a healthcare professional who works in a hospital contacted us to confirm that a WiFi/Internet connection is not needed (“we do not have WiFi in my area”). We confirmed that’s true and  then modified the App Store description to emphasize that particular feature of the app. The Professional Edition app has also received positive reviews from lawyers. Jeff Richardson, an attorney and publisher of iPhoneJD.com, wrote a high quality and in-depth review where he concluded, “I suspect that many lawyers have, like me, found the need to look up medical terms, such as during a break in a deposition…the Merck Manual apps are excellent sources of medical information and it is very useful to have all of this information at your fingertips on the iPhone for quick and easy access.”

The Home Edition (App Store link), which is among the top 20 paid apps in the medical category as of this writing, is proving to be a valuable resource for consumers. In the US App Store, Kessee wrote, “Great reference too, easy to navigate, tons of info at a reasonable price!!” and Mehall7 commented, “Easy to use and well worth the price. You won’t regret buying this.” Heather Leister, TheiPhoneMom who’s been mentioned in TechCrunch on more than one occasion, wrote, “This is one heck of an impressive app” and “I’m the type that likes to go into a doctor’s appointment having done some research and love having all this medical information on my itty bitty phone.” In his thorough review of the app at Medtapp.com, family physician Dr. Jojo Ferrer noted that the app enables users to “report bugs, suggest features, and sign up for the newsletter. Kudos to Agile Partners for enabling these in-app; it shows how much importance they give to customer feedback.”

As we said in our blog post when the apps launched, we’re proud of the work with our partners at Merck on the iPhone versions of The Merck Manuals. It’s now fulfilling to see the apps starting to be recognized as valuable references for consumers and healthcare professionals alike. To learn more about both iPhone applications, please visit the Merck Manuals page.

A Bit of History
In 1899, the pharmaceutical company Merck first published a small book titled Merck’s Manual of the Materia Medica. The Merck Manual (as it was later known) became a favorite of those involved in medical care or in need of a medical reference. Albert Schweitzer carried a copy to Africa in 1913 and Admiral Byrd brought a copy to the South Pole in 1929.

By the 1980’s, the book had become the world’s best-selling medical reference and was translated into more than a dozen languages. In 1997, The Merck Manual – Home Edition was published. Written in everyday language, the Home Edition is meant for anyone interested in medical care, but who may not have a medical degree. It has received critical acclaim and sold over 4 million copies worldwide.

The Merck Manual iPhone Apps
Agile Partners collaborated with Merck to bring the trusted content of the The Merck Manuals to the iPhone and iPod touch. “For over 100 years, healthcare professionals have relied on The Merck Manual for essential information on diagnosing and treating medical disorders,” said Robert S. Porter, MD, Editor-in-Chief of The Merck Manuals. “These two iPhone applications now provide the trusted information in a form that is even more valuable for consumers and healthcare professionals on the go.”

The Home Edition app for consumers puts the trusted medical reference at the user’s fingertips, whenever and wherever it’s needed … while on the soccer field, a family vacation, a business trip abroad or getting ready to see a physician. An “Emergencies & Injuries” section that is accessible from the home screen was developed expressly for the application.

The Professional Edition app for healthcare professionals addresses thousands of diseases and treatments, features clinical approaches to each category of disorder, and provides specific guidance on patient evaluation. The app includes a ‘Find by Symptom’ section that is accessible from the home screen.

Agile Partners and The Merck Manuals
Agile Partners’ contributions to the The Merck Manuals actually began well before the development of the iPhone applications. In 2005, Agile helped Merck develop The Merck Manuals Online Medical Library which includes the Home Edition and Professional Edition. The online Home Edition won the 2005 Webby Award for Best Health Website and was a finalist in the prestigious Best Practices category. (The 2005 winner in the Best Practices category was a small, up-and-coming company named Google.)

We’re proud of our work on the online and iPhone versions of The Merck Manuals, and hope they continue to serve as valuable references for consumers and healthcare professionals alike. To learn more about both iPhone applications, visit the Merck Manuals page.

When TabToolkit launched two days ago, Dave at fretbase.com wrote, “Just like GuitarToolkit, we love TabToolkit because it does exactly what it claims it will do … when you load your Power Tab and Guitar Pro tabs, TabToolkit makes you feel like you have been transported into the future.” Dave continues to say, “We think it is well worth its price of $9.99 and a must have for all guitar players who play with tablature.” Travis Ehrlich at geardiary.com wrote yesterday, “Agile Partners have really outdone themselves with this app! TabToolkit is attractive, easy to use and fast … this is a quality app!”

Matt Rosoff at cnet’s Digital Noise blogged, “…a very sophisticated app that performs well — no freezes or stutters, as I’ve experienced with other music-oriented apps.” TabToolkit was named a Cult of Mac Favorite by Lonnie Lazar, who also commented, “I can say without reservation that Agile Partners have created an incredibly useful, well-thought-out app.”

TabToolkit has also captured the attention of mobile technology bloggers. Over at thismobilelife.com, the headline was, “TabToolkit: The Guitarist’s NEW Best Friend!” At TotalApps.com, David Kint wrote, “If you had asked me two weeks ago if I ever thought such a multi-featured application would run on an iPhone or even be possible I would have had serious doubts. Yet, here it is. If you own a guitar and an iPhone then the TabToolkit and GuitarToolkit are two essential applications you really must own.” Palm Sounds featured the TabToolkit video.

Finally, we’re fortunate to have received incredible feedback from TabToolkit customers around the world. JackHarteveld in the UK wrote, “This is a fantastic app, definitely worth the price! A clean, easy way to take tabs with you, with the added bonus of letting the device play the songs out for you! A great companion to GuitarToolkit and a highly polished app; an easy recommendation for guitarists.” NickMaher in Australia wrote, “Very polished application, well worth the money” and Vab-1971 in Belgium said, “Application très soignée, un vrai régal.” I’m not entirely sure what that last comment says, but it  came with a five-star rating!

Thank you to all the writers who reviewed TabToolkit in the first two days of its launch, and a special thanks to TabToolkit customers around the world for providing us with your comments and feedback.  Please keep it coming — we’re dedicated to enhancing TabToolkit and all our products, and keeping our customers happy!

If you’re unfamiliar with what a tablature (or tab) file is, it’s a simplified form of music notation that started out for guitar music, but has expanded over the years to enable the creation of complete music compositions. Wikipedia entry for tablature

TabToolkit was a significant technical challenge in a number of ways. By rendering out music notation in realtime and coupling it with synthesized instrument output, we feel like we’re really expanding the capabilities of the platform. We initially planned on launching 1.0 without synthesized audio, but after hearing a prototype implementation work for the first time, we realized we just had to do it.

Creatively, there were plenty of hurdles to overcome as well. We had to create our own font for the music notation display. The combination of Adobe’s licensing options and the lack of good, freely available music notation fonts made creating our own the most compelling option.

A few of the features in TabToolkit:

• Support for the following tab formats: Guitar Pro, Power Tab, text and PDF *
• Audio synthesizer allows you to hear the instrument being played
• View both standard music notation and tablature notation
• Automatically scroll through music with tempo control
• Turn on a metronome with a wide range of sounds
• Select from multiple instrument tracks
• Display a fretboard (guitar or bass) or keyboard that shows finger positions
• Upload tab files directly from your Mac or PC
• Download tabs from the Internet using the built-in web browser
• Portrait and landscape orientations for viewing while docked or on a music stand
• Built-in help, news and feedback support features
• Lefties welcome! Lefty-mode inverts the fretboard to display correct finger positions

* Instrument audio, metronome, auto-playback, music notation and multiple tracks are suppported for Guitar Pro and Power Tab files

Buy it in the App Store or visit the TabToolkit page to learn more.

• Includes chords for alternate tunings. Massive chord library (over 500,000 chords now).
• Chord finder: simply touch the notes on the fretboard that make up a chord, and GuitarToolkit tells you what that chord is! This is a lot of fun and a great way to learn about those great-sounding chords you’ve been playing.
• You can now create your own custom tunings
• Metronome is more stable and accurate
• Direct support for 6- and 12-string guitar, 4-, 5- and 6-string bass, banjo, mandolin, and ukulele with a full chord library, standard and alternate tunings for each instrument
• You can change the reference pitch from A440
• Added the ability to show notes or intervals on chords
• Added the ability to show intervals on scales
• High contrast mode for the tuner
• More chord types added
• Help, news and feedback system added

Screenshots of a few of the new features:

High Contrast Tuner Mode	Chord Finder
New Instruments	Alternate Tuning Chords
Note Intervals	Ukulele!

Take a look a GuitarToolkit product page for more info or open GuitarToolkit in the iTunes App Store.