There’s plenty of rightful skepticism about the use of mainstream displays for multitouch in general purpose computing. And why not? As a full-time replacement for other input, multitouch probably doesn’t make sense. But for music, the equation is changing. Multitouch capabilities are showing up on commodity-priced PC computers like the multi-touch enabled HP laptop models – the tx2z seen here starts, incredibly, at US$850. And because computer musicians are looking for more control, having a touch-enabled display (even single-touch) just makes sense.

The screen for a laptop musician is a huge piece of real estate. Finally, instead of sitting dumbly in front of you glowing, it can become an X/Y controller or give you shortcuts for controls or provide additional parameters. Yes, using a touchscreen exclusively can result in the dreaded “gorilla arm.” The ergonomics of using a vertically-oriented screen are extremely poor – if you use it exclusively for an extended period of time. But if you look at the way people are using these touchscreens, for incidental control in combination with other things – and the ability of convertible laptops to transform into a horizontal orientation – I think this is no longer the deal killer it once was.

At top, an HP laptop ($850) plus the free version of Sensomusic’s Usine is all you need to create a multitouch interface for Ableton Live. Correction: right now this is limited to single touch only, but multitouch is supported in the hardware, in drivers, soon in Windows 7, and support is promised for a future version of Usine. The point still stands — as does the ability to optimize controls for your fingers. Being able to use more than one at once will, of course, be that much better.

Fractal (see Myspace) uses the combination to play Ableton Live with some simple controls. If you get hooked on Usine, you can get the full “Pro” version for EUR70 with additional patches and objects.

The one major remaining obstacle to multitouch, at least, is cost. If you don’t especially fancy buying a new HP laptop, add-on kits still run in the range of US$800-900 (meaning, ironically, you might as well just buy the HP instead). Laptop vendors are still slow to adopt the technology, though that could change when Windows 7 ships later this year. (On the other hand, tablet PCs, even when they were shipping in relative quantity, often were constrained in available configurations and either skimped on specs or demanded a significant premium.)

But let’s not complain too much. The simple reality is you can add an HP laptop now to a live rig as a performance instrument for under a grand.

No doubt about it: touch is coming to more screens near you. But there’s no need to disappoint your current beloved laptop. $200 kits can turn your laptop into a functioning touchscreen.

Now, as I’m working with JazzMutant’s Lemur this week, before you get excited, this is no Lemur – or even anything like your iPhone or iPod touch. Sensitivity and accuracy are workable, but not exceptional, the overlay is pretty simple (as you can see in the video) rather than integrated with the display, and this is single-touch only — not multi-touch. Lastly, on a conventional laptop that isn’t convertible, you may miss the ability to fully extend your laptop perpindicular to your body. (Having the screen be parallel can put your arms in a fatiguing position.)

But that said, there’s a lot of potential once you have the ability to reach over and make quick gestures on a laptop screen that control a set. You might make your own instruments and effects or controller dashboards in a tool like Processing or Reaktor. And at $200, this could be a brilliant way to retrofit a machine and breathe new life into it. There’s support for Mac, Windows, and Linux; you just plug in via USB.