Kent Clelland

Interview by Jonathan Leonard

Software developer Kent Clelland of Native Instruments has been working on a new plugin called Spektral Delay.

A very innovative product, it allows for real-time FFT to divide each channel of a stereo signal in up to 160 separate frequency bands for individual control. These bands can then be selectively raised or lowered in level, and then their delay time and feedback changed as well. The interface presented is elegant, and the engine is fast.

Kent took a few moments from the NI booth at winter NAMM 2001 for an interview.

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Jonathan: Ok! We have Kent...

Kent: Clelland.

Jonathan: Yeah man, so, talking to Kent from Native Instruments. You're one the developers for the new Spektral....

Kent: I developed the new Spektral Delay in conjunction with my partner, Joachim Haas. Its a project we have been working on for the past five years and since I have been working with Native Instruments the past almost two years now, we have decided to take the project into the realtime world through the experience of Native Instruments and its been very successful for us.

Jonathan: Sweet! So, I checked out some of the demos and stuff...lets say I am someone who has a pc for post production. some mild software synthesis...what would someone like me use the spektral plugin for?

Kent: The spektral plugin is very unique in the sense that it offers you a super-wide range of possibilities. You can go in there and really isolate single frequencies and do microscopic sort of editing of the frequencies individually to correct small problems. Say, in a mastering or a post production situation. But on the other hand, you can go in there and re-sculpt the entire spectra into something totally different than the original input material.

Jonathan: Sure. And this is more than just something that is a simple high resolution multi-band equalizer.

Kent: Definitely, NOT. This is real time FFT processing. Its the first real time FFT processing from Native Instruments and I would say its the first real time FFT processing product that breaks the $200 barrier. So what is particularly special about it is that ah...yeah it does...you said 'its not a simple thing'. Its definitely NOT a simple thing; its actually the exact opposite. Its a very complicated technology that we have spent, really, literally, years trying to simplify into a very intuitive and simple to use graphical user interface.

Jonathan: Which it is. I think the graphical user interface is very elegant and simple to use as demonstrated by Jake. You can immediately begin doing some really really cool...

Kent: Thats exactly right. Thats one of the things that was the biggest challenge for us was how to deal with such massive amounts of complex data yet give the user very simple control over this kind of thing. Previously if you wanted to do this kind of delay or spectral processing, you really had to be a programmer just to wade through the amount of data in order to achive just the most simple results. But now the basic simple tools that everyone is used to using, that we provide with spektral delay; you can go in with just a pencil and draw eq curves or delay curves which makes it very very simple to use. And a very powerful tool.

Jonathan: Sure, so you don't have to use this as a delay processor on seperate frequencies. You can actually use it as a multiband eq at the same time.

Kent: Exactly. You can use it as a multiband eq, you can use it to fix small problems with your mix, for example. We also offer a wide range of what we call input modulation plugins which offer a very creative range of different spectral distortions, so to speak. Ranging from minute subtle things like taking random holes out of the spectrum; to doing pseudo time compression-expansion effects. Which for the sound designer or the sound effects designer; is an incredibly creative tool.

Jonathan: Yeah definitely. I saw that yesterday. You can get some almost kind of granular effects in terms of being able to seperate...

Kent: Yes. Realtime Granular synthesis is really one of the big creative features of the spectral delay because not only is everything fully MIDI automate-able but there is also built in LFO. so you can get your curves and your gestures flying around on the screen so FAST that you are just MASTICATING this signal into something which is just the sonic or the spectral essence of the sound but no longer organized in the original way it was input into the system.

Jonathan: Totally. And that comes through in the brief example I was given. The source material was contorted from something that was just a basic kind of notch frequency subtraction getting those different effects, to completely different sound-morphing possbilities. Its really cool and its really fast. Where does the FFT come in?

Kent: Well basically what happens is the audio signal comes in and is immediately analyzed using the Fast Fourier Transform process. Now this has previously required supercomputers or very very intensive CPU processor usage. But we have spent many years optimizing this process and working to make it so it will operate in real time. Of course we offer the possibility for people to decide at what resolution they would like to analyze the frequencies at. So those people with fast computers can have much higher quality resolution in their FFT analysis and resynthesis. However we also offer the possibility to reduce that analysis level or that analysis resolution so that people with computers which are not so fast can still have a very good time with the program.

Jonathan: Yeah I think so because I saw it working- totally doing all that stuff, and CPU utilization didn't seem that out of hand at all.

Kent: Yeah, on a G4 400 I can run two instances of the stereo spektral delay and one instance of the mono version with absolutely no problem in my mix with a whole bunch of other tracks going...

Jonathan: Thats amazing! Having run on other systems; pc's and Macs-having run FFT analysis programs just for trying to figure out or analyze an artifact or something you can just about bring the machine down.

Kent: Yeah it used to be the kind of thing where you would think about, sort of ponder what you wanted to do with the spectrum, write a program to do it, go to bed and wake up the next morning to see if it actually worked. But now we just go in there, turn it on...we make our gestures, draw in what we want to hear and we hear it immediately because the real time sonogram are always running. You see the input signal and you have really a reference as to what you can do. What sonic or spectral kind of material you have to work with. And so as soon as you go in there and start editing the matrices, you see the input and the output which makes it a very intuitive way to work.

Jonathan: Wow. This sounds like THE TOOL that someone like you or I have been waiting for, for all these years to really have almost total control over the frequency domain.

Kent: That's absolutely right. I mean I've always been the kind of person who instead of using something off the shelf or some piece of hardware to make my music and my sound; I have always opted to make my own software so I sound like ME. But the cool thing about the spektral delay is that yeah, it gives you those tools to really develop your own kind of sound. Every sound you put into it is going to have a different spectra and you can analyze that and do whatever you want with it and really decide how YOU want to sound.

Jonathan: Now is there any way...does the FFT capability in this paticular plugin have any...did you guys put in any functionality where you can kind of record the sonogram or pattern or audio source, and then turn around and be able to apply this to another audio source?

Kent: At this point, no. We have programs which do something very similar to this. However, these programs will not be released until a little bit later. Spektral delay is the first in a series of spektral processing software.

Jonathan: As a whole series?

Kent: Exactly. And the delay is the first in a series.

Jonathan: So do we have some resynthesis to look forward to?

Kent: Pardon me?

Jonathan: Do we have some resynthesis to look forward to?

Kent: Oh, definitely. There are very very exciting things to come from the spektral series.

Jonathan: Excellent! Well...Kent, thanks for taking the time to come out here and talk to the folks at Sonikmatter and stuff. I definitely love the work you are doing so far and its going to be helping me in my music.

Kent: Great, thanks a lot Jonathan!

Jonathan: Thanks man!

For more information about Spektral Delay and other Native Instruments products, visit the Native Instruments site.