Jan Abildgaard Pedersen is Dynaudio’s chief technology officer. He knows everything about digital signal processing (DSP). And he’s putting all that knowledge into the company’s range active of active speakers – the Focus XD and Xeo.
“Traditional” hi-fi people might see Jan as the devil incarnate (he really isn’t; he’s a lovely fellow), but that’s probably down to a misunderstanding of what DSP is. Or, rather, a distasteful memory of what it was: a somewhat shonky way of trying to make an imperfect situation better. And doing it badly.
The theories behind DSP are decades old – more than half a century, in fact – and it took until the development of the CD format for them to be put into practice (when they were already quite long in the tooth).
The technology relies on computing horsepower to deliver results. The more, the better. And because the processors of the day weren’t up to the job, those results just weren’t up to snuff.
What isn’t DSP?
When most people think of DSP, they think of algorithms that attempt to make your living room sound like the Royal Albert Hall, or that add huge, unnatural reverb effects to the sound. We aren’t talking about stuff like that, or even upconverting stereo (or mono) sound to multichannel format. This is all about far more fundamental concerns: phase, detail, dynamics and timing.
Essentially, DSP compensates for the laws of physics that acoustic designers wish didn’t exist. It’s there to account for challenges that your room, or the physical design of the speaker, present – without any loss of information. The idea is that it makes speakers sound as they should.
It can iron out certain frequencies, and prevent the loss of information in the signal path. It can manipulate the signal to offset irregularities in the room itself. For Dynaudio it’s all about getting as close to the original recording as possible, regardless of the situation the speaker finds itself in.
And doing that in the digital domain is far easier than it is with an analogue signal.
Digital is a collection of ones and zeroes; voltage or no voltage. If the voltage is above a certain threshold, it’s a one – below it, it’s a zero. And that gives leeway: if the threshold is 2.5V, then anything below it is a zero – so while the information going in might have irregularities, the information coming out does not. It’s the same every time.
Working in digital and correcting for those irregularities opens up a world of possibility when it comes to reproducing sound.
In the case of the Focus XD and Xeo, one of the applications is as simple as the rear knob, which lets you tell the speaker where it is in relation to the room: in a corner, next to a back wall, or free-standing. The DSP takes that into account and is designed to make sure the speakers sound the same whichever position they’re in.
After all, that’s why you bought the speakers – for their sound. Why would you put up with it being different depending on where you had to place the cabinets?
It works in the crossover, too. Because active speakers have a separate amplifier for each of their speaker drivers, DSP gives the engineers far more control over the individual frequencies they deal with – and, therefore, their overall performance. It means they can use more sophisticated, lower-distortion high-order circuits, and get closer to eliminating the natural distortion any physical speaker inherently has.
And because the advanced DSP systems Dynaudio uses are so powerful, they can do that with all the data Hi-Res Audio chucks at them just as easily as they can with the relatively sedate pace of ones-and-zeros thrown out by CDs.
What else can it do?
There’s more on the horizon. Jan and his team, working at Dynaudio’s brand-new R&D centre at its headquarters in Denmark, are busy working on some astonishing tech that could revolutionise the way we listen to music. And it’s all down to DSP.
“We’re also exploring how it can redefine the experience – without compromising audio quality.” Room adaptation is one of those opportunities, he says – and it’s far more far-reaching than the little knob on the back of the current active speakers. “We want a speaker that’s designed and tuned in our listening rooms to sound exactly the same in any other room,” he says.
The goal is for the home listener to hear precisely what the engineers did – and it involves a massive amount of measuring, algorithms, data… and patience.
The team is also researching the viability of ‘sound zones’. “Classical music is playing at the sofa, and rock is playing by the armchair, in the same room, from the same speaker system, without affecting each other,” Jan says. Yes, Sound Zones are a theoretical possibility with the tech he and his engineers are pursuing.
But there’s one thing DSP can’t do – and that’s make a bad speaker sound good. Jan says they always start at the base level with a good loudspeaker; the extra computing power is just the icing on the cake.
So, no – DSP isn’t evil. In fact, it could very well be the redemption of traditional hi-fi.
To find out more about Dynaudio’s active speakers, click here >>