What was the artistic process that you and Rick Smith from Underworld went through to adapt the music for the interactive iDrum model?

Actually, everyone in the Underworld camp was asked to make a list of possible contenders and from that list Rick and I discussed which tracks would be the most suitable in terms of user interactivity and also with a view to encompassing a wide range of Underworld songs.

Using the Underworld Live multi-tracks I would then break each song down into component parts and start reprogramming for iDrum. Rick was always the barometer as to whether a particular tune or the component parts were working or not and I'd make adjustments accordingly.

I knew we'd attained the goal of making a song as much fun as possible for the user to interact with when I'd ask Rick for his opinion and he'd completely ignore me. I'd then watch him while he jammed with that track before emerging anything up to an hour later, grinning and saying, "Bloody Marvelous."

What was the technical process you went through in adapting the songs?

We started with the Underworld Live multi-tracks which are a mixture of audio and MIDI parts, sampling from their 'special 909' wherever necessary. The main criteria was distilling the original song until you had the essence of what made it great and then to try and break that essence down further into samples that would entice the user into playing... or, to use a word that's crucial to the Underworld philosophy, "jamming."

Once we'd done that, it was a case of using the desktop version of iDrum and reprogramming the song with the essential parts, both to audition the components within the context of the rebuilt song and to test the groove. If Rick felt a particular sample or loop wasn't engaging enough for the user, we'd change it and because Rick was often busy writing for the new album. Darren Price was brilliantly attentive when it came to throwing me alternative samples and loops.

Additionally, because for Underworld, 'the groove' is everything, occasionally I'd have to move a loop slightly to firm up the feel of the song. But once this was completed and Rick was happy, we'd mix the song, testing on the iPhone app via different sets of headphones as well as through their big Funktion One system. What was bizarre with the latter is there's this tiny little phone plugged into their Funktion One PA and it's generating this massive sound. The audio quality and the tactile nature of iDrum was such that Rick immediately raised the idea of incorporating it into a live show.

Did you run into any technical challenges when adapting the songs, and did you use any iZotope software or treat the raw samples any way?

I'm a huge fan of RX, Radius and Ozone but, bizarrely, this is probably the only project that I've done in recent years where I didn't use any of those tools. The fact is that the Underworld Live set has been refined over the years so the raw samples were great from the off and didn't need treating. Sometimes I'd have to boost the level of a sample to make it sit, but Rick decided early on that he didn't want everything normalized because the space in the overall mix could vanish. I have to say I questioned this at first but after we did a test using normalized and non-normalized versions of Dark Train it was clear that he was absolutely correct.

Technically, the main challenge was in adapting the songs to iDrum's 16 steps, 16 instruments and 16 patterns. With some tracks that made things nigh impossible. For example we talked about breaking down the main Rez riff into individual notes but quickly realized that wasn't going to be possible if we were going to keep any other instruments. However, I do believe there's a beauty in limitations which makes you think in different ways so you overcome them and the song that highlights this is "Born Slippy." Essentially, the first chord in "Born Slippy" plays over 2 bars so we chopped it into two one bar segments taking care to put a tiny fade in between each one. What's really neat is that it works in the context of chained patterns but also the second part of the chord can also be jammed with independently.

What was the idea behind VoxJam track?

We wanted to do something unique which really played to the strengths of iDrum and the idea of using spoken words instead of drums really came from a long term project of Rick's called "Bungalow With Stairs." This is often used within tomato projects or art installations, and we thought it'd be a really neat thing to let people play with something that had no previous form or existence - that way they could get truly creative without ever comparing it to something that had gone before.

The vocal samples in VoxJam actually come from "Best Mamgu Ever" (Oblivion With Bells) and are taken from a non-gated version of the vocals you hear on the original track. We took a bass note and a chord from "Beautiful Burnout" and combined them with pulses from "Glam Bucket" and a chord very reminiscent of the one played at the end of the Everything, Everything DVD. The tempo was set at 70 BPM so other samples within the app could fit nicely. For example, importing the "Crazy" vocal from "Pearl's Girl" or the "Mo Move" Violin Echo works brilliantly.

For more information on Underworld, visit www.underworldlive.com. For more information on Dave Spiers, check out GForce Software.