I, for one, welcome our new DSP overlords

Post date: Sep 2, 2015 4:14:32 AM

I did something the other day that I honestly thought I'd never do again: I bought a commercial speaker.

Here was the story. At my current office, the noise level needs to be down pretty quiet. Something like the Speedster--which I gladly rocked daily at my last job--would have been overkill. So I was stuck with either crappy Dell USB-powered computer speakers, or an even crappier "soundbar" attached to the bottom of my monitor. Either way, I was getting crap. I lusted for bass, maybe just a hint of bass... even a low midrange. I needed some real speakers, badly!

I went to my stash(es) in search of small drivers that could make a tiny computer speaker. However, I ran into the same problem I've written about in the past: it seems that--regardless of the driver--in an enclosure smaller than 4 Liters, I just can't get satisfactory bass. Basically, nothing below 100 Hz, and usually a large hump around 150 Hz. And that ain't bass. In fact, if anything I'd rather have no bass than have that annoying 150 Hz boxy "punch."

Am I banging against the limits of the laws of physics and acoustics? Perhaps. But there is a digital solution: EQ. That's right, with the slide of a fader, I can suck that 150 Hz bump into oblivion. And while I'm at it, why not boost around 60 Hz? Is this sort of frequency shaping any different than what Linkwitz does with his brilliant designs? Using EQ placed before the amplification stage can make good economic sense. It saves one not just money on passive crossover components, but also on lost energy being thrown away as heat through large coils and resistors.

Maybe EQ is too garish of a word; let's say "Digital Signal Processing" instead. So what can DSP do for us designers? Um, with the cheapness of computers and microprocessors these days, pretty much anything we can dream up--once someone comes up with an turnkey solution for DIYers to implement. In my opinion, as neat as MiniDSP and Ultimate Equalizer are, there's still too much setup, and too much ancillary equipment needed for there to be a mass appeal.

Thus, most of the good DSP toys are still in the hands of the manufacturers. I went over to Best Buy to take a listen to what kinds of DSP magic was currently available on the consumer market. Specifically, the little Bluetooth speakers. There were definitely some interesting performers breaking the size/performance barrier, but one stood out heads and shoulders above the rest: the unassuming Sony SRS-X33. Here was a device about the size of a pound of butter that was putting out REAL bass down to 60 Hz. Not fake bass; not harmonics. Of course, without DSP, this would not even be possible. In addition to that, seeing some measurements of the speaker shows that Sony's engineers put a lot of effort into shaping the overall response to make a great-sounding speaker, not just something to play background music or have a cheap party. The Sony's FR is in Blue in that link. Notice the big fat dip around 150 Hz. Coincidence? I think not! (Not my measurements, but a good article. Full link here)

And at $100, really the Sony SRS-X33 is not that bad of a deal. It's actually on the low end of what are considered "good sounding" Bluetooth speakers--not that that metric has much of any meaning to me. So to put it into terms I could understand in order to justify the purchase: it's the same price as a pair of Dayton RS180, or about 1/2 the price as one 5" Scan-Speak Revelator woofer.