The iPad is often perceived as a fun yet altogether unnecessary gadget, and that leaves many wondering whether they can justify the purchase when their existing equipment will probably do. Despite being a great eBook and magazine reader, a games console and quite possibly a productive accessory too, the iPad really excels when it comes to making music.

This might just be the excuse you need to drop next month's wages on Apple's flagship device, though you shouldn't expect much for free. iOS has a swelling catalogue of melody, beat and noise generators which are considerably cheaper than the hardware they are designed to replace.

If you're looking to make music with your shiny new tablet then this is the right place to start.

Impaktor ($4.99)

Introducing one of the most innovative musical apps on the App Store, Impaktor is a fully-fledged drum synth that takes a unique approach when it comes to input. Instead of tapping on-screen in order to register kicks, snares and hi-hats the app uses your device's microphone to allow you to play whatever surface your iPad or iPhone is currently sitting on. This is a universal app which means that's one price to pay to make complex loops and patterns on all of your devices.

This requires headphones (without a microphone) and as you can imagine offers one of the most useful and immersive drumming experiences on iOS. Really, you can make a solid 6-track loop with this, export it to WAV or AudioBus and even use the program with your mouth, which means anyone can create convincing drum loops - all you need is a quiet environment. Because this is a drum synth, there are no samples used so finding a unique sound is a simple case of fiddling with the included settings, or modifying one of the many presets.

http://www.youtube.com/watch?v=KjWT5ixO9Ck

CP 1919 ($9.99)

An obscure yet affordable synth app which functions like no other - a physics-based fluid simulation is somehow attaches to a synth engine with 24 oscillators resulting in a unique, droning wall of sound that is going to be hard to replicate elsewhere. Naturally being a fluid-driven synth you can manipulate the fluid with your fingers while adjusting sliders to create unique sounds for use in compositions.

There is also a keyboard interface, so you're not strictly limited to new-age noise making but let's be clear this is definitely one of the more restrictive synths on this list. If you're into dark ambient sounds or fancy tweaking an interface that looks like a Joy Division album cover then this one is for you.

http://www.youtube.com/watch?v=ROkEG7z-AoQ

Addictive Synth ($9.99)

Another moderately priced synth, another highly-rated noisemaker. The onus here is on simplicity and the ability to create complex sounds in a user-friendly manner. There are still knobs to twist and buttons to push, but it wouldn't be much of a synth app if there wasn't. Addictive Synth comes with a few very strong features not least a particularly powerful arpeggiator and a spectral noise generator.

There are a ton of included sounds with which to create wistful melodies and grinding bass grooves, though the presentation isn't quite anywhere near what some of the more expensive apps offer. For the money you won't get another app that can do quite so much.

http://www.youtube.com/watch?v=ekI7_Osoers

GarageBand ($4.99)

The cheapest app here and the only one on the list from our dear overlords, Apple's GarageBand might be synonymous with five-minute messabouts but it's not to be discounted. Included are a good range of keyboard instruments, many of which can be tweaked, as well as virtual orchestras, support for guitar input and smart instruments that take much of the effort out of creating impressive sounding songs.

I've made no secret of my adoration of this app and I think it's one of those must-have iOS apps for the money. There's also support for jamming which involves connecting a few iPads and iPhones together wirelessly and capturing all played audio on the host device. It's no iKaossilator or Animoog, but it reaches far broader audiences and is very user friendly.

http://www.youtube.com/watch?v=ZMRTvU17dMI

Figure ($0.99) [No Longer Available]

Figure is very different to the rest of the apps here in that it's the fastest yet probably most restrictive way of making music. Little comes close in terms of workflow speed, but then again this becomes its limiting factor as well. With three layers (or channels) to play with, Figure allows you to choose from a decent selection of in-built bass, lead and drum sounds which you can then arrange as you please. There are a few modifiers for each sound, but don't expect anything amazing (and you will get slightly tired of the same-old sounds after a while).

Despite originally being an iPhone app the iPad version is virtually identical and thanks to the extra screen real-estate allows for much finer control over your composition. Since my initial gushing review there are even more features including UI enhancements, new sounds and wireless start technology for chaining devices.

http://www.youtube.com/watch?v=gLLjRH6GJec

Sunrizer ($9.99 iPad) or Sunrizer XS ($2.99 iPhone/iPod Touch)

From the same developers as Impaktor comes Sunrizer, a convincing synth for iPad which also comes in a slimmed-down iPhone version that costs a third of the price. Featuring two "warm-sounding" analog modeled oscillators, 2 sub-oscillators and more options than most beginners will ever need, Sunrizer is capable of producing some wonderfully complex sounds. If you're not keen on figuring out what all the buttons do then you'll still be able to jump right in with over 380 presets included.

The app is fully MIDI-compatible, which means you can plug in your MIDI keyboard using the Apple USB connector, commonly sold as a camera connector. Sunrizer is easy to program thanks to MIDI Learn, allowing you to quickly choose hardware controls for the many variables. Export to DropBox and file sharing is useful, but not as useful as AudioBus export which will rock your world once you've built up a decent catalogue of similar apps.

http://www.youtube.com/watch?v=tYbikIySzk0

TouchOSC ($4.99)

TouchOSC is not a music-making app per se, but instead offers a hardware-like control interface for compatible desktop software. That means you can use it as an interface for Open Sound Control-compatible software for performing live or simply getting more hands-on with your set-up. Compatible apps include big names like Apple Logic Pro/Express as well as Ableton Live, Renoise, Reaktor, REAPER and many, many more.

While touchscreen-based music controllers are never going to offer the level of tactile control seen in dedicated hardware efforts, TouchOSC closes the gap considerably. It does this with it's aggressively afforable price point, excellent compatibility and the best feature of all: a completely customisable layout. You can literally design from the ground up to suit your particular workflow with a variety of sliders, buttons and even XY pads which can then be assigned a function within your digital audio workstation. The perfect accompaniment to any live performance or studio set-up at a fraction of the price of a hardware controller.

http://www.youtube.com/watch?v=4v_Eb2j0vZ8

AKAI iMPC ($6.99)

Finally for a slight twist on the music-making angle I've decided to include another software replacement for what is a legendary piece of hardware, iMPC. Imitating the iconic Akai MPC range of samplers, this iPad-only app is the closest you'll get to owning a real-life MPC without spending hundreds of dollars. In fact, it's only $6.99 for the moment (though I expect that price will be rising at some point).

So it's not as dynamic as an actual MPC, you'll notice a few things you want to do with your fingers are near-impossible on this iPad version but that doesn't mean it doesn't rock. Oh it rocks, with a proper sampling interface, the legendary MPC workflow, 16 pads, 16-level control and a ton of in-built sounds to get you started. This is one of the best apps on the store for sheer entertainment value, particularly if you're always tapping your fingers and coming up with beats.

http://www.youtube.com/watch?v=QDAwVNz3aXs

Did I miss your favourite iPad music making apps? What do you think of this list? Add your own recommendations in the comments, below. If you've created any music with your iOS device then I'd love to hear it too!