There's no doubt that a soundtrack can significantly enhance the immersiveness and emotional impact of films and TV programs. But can some audio accompaniment do the same thing for books? New York City-based startup Booktrack thinks so and has released an iOS app - with an Android app also on the way - that adds soundtracks to eBooks. As the user reads they can listen to ambient background noise relevant to the book's current setting, specific sound effects synchronized to the text as it is read, and music. But does a soundtrack "boost the reader's imagination and engagement" as the company states, or does it just create another distraction to be overcome when delving into a book on the bus on the way home? I decided to download the app and find out.

Like most people, I find the best environment in which to immerse myself in a good read is a near silent one, which is why the concept of adding some audio accompaniment to a book seemed a bit counter productive to me. But, keeping an open mind, I downloaded a couple of Booktrack books from the iTunes app store and gave it a whirl.

Rather than showing up in iBooks, the books all appear as individual apps on an iPad/iPhone or iPod touch. Unsurprisingly, they're also much larger than your average eBook - the two I downloaded were 43 MB and 53 MB. Upon startup you'll be presented with a quick start guide to show you how to navigate the book. There's the standard swipe to turn pages and a single tap will pause the audio. As with most eReader apps, there's a selection of fonts to choose from (Palatino, Times New Roman and Georgia), choice of color scheme (white on black, black on white and sepia), and the ability to enlarge or reduce the size of the text.

When reading, the app is designed to learn your reading speed and adjust the soundtrack so it matches up to where you are in the text. As you make your way through the text a progress indicator lets you know where you're peepers should be looking to match the soundtrack. If you're falling behind or speeding ahead then a periodic double tap of the word you're up to will reset the progress indicator and the soundtrack. You'll probably have to pull it into line quite a few times when you first start up, but it learned my approximate reading speed pretty quickly.

The default progress indicator consists of an arrow in the right hand margin that makes its way down the screen to indicate which part of text the audio is currently synchronized with. There's also the option to have each individual word highlighted by an underline or ball in sequence. The arrow indicator is distracting enough - my eyes were constantly darting over to the right of the screen to check if I was keeping pace with the soundtrack - but an underline or blue ball shooting along under the text turned the usually relaxing act of reading into a downright stressful experience. Thankfully, the progress indicator can be turned off altogether, but then you won't know where the soundtrack is up to. No matter how well you've trained the app, I don't know anyone that reads at a perfectly consistent rate.

The audio itself is broken up into three layers: Ambient, which plays general background noise to set the scene - birds chirping while a character walks through the woods, for example; Sound Effects, which includes specific noises mentioned in the text - knocking on a door, etc.; and Music, which is tailored to the mood of the scene. The volume of the three audio layers can be altered individually to let users find their preferred mix.

The default setting sees all three audio layers activated, but after only a few minutes I was forced to first turn the music down, which was quickly followed by turning it off altogether. Not because it didn't suit the mood of the scene - if I was watching a movie I'm sure the music would have been appropriate - but it was just too distracting. So instead of drawing me into the book, it did exactly the opposite.

This left the sound effects and ambient noise. The sound effects were the next to go. Like the music they were too distracting, but for a different reason. The sound effects only came up when a specific reference was made to a sound in the text, which made it feel like I was listening to an audio book. As a result I kept waiting for the dialogue to be spoken as well. It was also distracting if I wasn't up to exactly right place in the text when a sound played - I'd either be surprised by a sound just ahead of time or reach the mention of a sound and be waiting expectantly for it to play.

This left only the ambient noise. Unsurprisingly this was the least intrusive of the three audio layers - maybe because it wasn't as time specific as the others. As a result, it was the only one I could probably get used to. Still, even the crackling of the fire in Holmes' sitting room eventually became too distracting and I was forced to turn the ambient sound off completely too - leaving... a standard eBook.

The lead investor of Booktrack is Peter Thiel, who also co-founded PayPal. Somehow I don't think he'll be seeing the same level of success here. But I'm just one person so what do I know? Some people might love this. Thankfully Booktrack has made it easy for people to make up their own minds by offering five of its six launch titles available for free in the iTunes Store. The sixth, The Power of Six by Pittacus Lore sells for US12.99. An additional five titles are listed as "coming soon" on the Booktrack website.

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