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Bad Speakers Cast a Bigger Shadow

by Bryon Moyer

January 30, 2012 at 1:44 PM

Let’s face it: a lot of the speakers we have these days are crappy. I know how my laptop sounds; I used to attribute that partly to what I assumed was a cheap sound card (since, why would you put an expensive one in something with crappy speakers?). Later, I retired that laptop for use as a “gateway” for things like Netflix and Pandora, driving into a monitor that also had speakers. And those speakers also sucked.

But when I connected the laptop audio to real speakers, suddenly I got rich sound like I had never heard from a computer (although I’m sure it would have sucked for an audiophile…). In other words, it wasn’t the sound card at all: it was the speakers that transformed music into a tinny mishmash.

I had a conversation the other day about this with Les Tyler, president of THAT Corp., which has a division dedicated to dbx technology for TV audio. They’re trying to address this issue, since no one who makes monitors or TVs (in particular) seems to want to use decent speakers – they’re often not even willing to have the speakers face the audience (what a concept!). It’s a cost thing; video is king; audio is… well, perhaps it’s a throwback to Warner Brothers’ Harry Warner in the ‘20s: “Who the hell wants to hear actors talk?”

In case you think they’re going to find a way to get 12”-woofer base out of a 1” speaker, they will assure you that “we can’t change the laws of physics.” But they say that they make bad speakers sound better, essentially by measuring the transfer function of the speakers and then applying the inverse to the sound in a DSP software algorithm.

It’s not quite that simple –the actual inverse transfer function would apparently be huge, so it’s a good approximation. The function is also a function of loudness, and, hence, must operate dynamically to keep the signal from overdriving the speaker.

The solution is split into two pieces: the TotalSonics piece is what ends up in the TV itself, adjusting the sound in real time. Their TotalCal product is used by developers to calibrate the solution to the specific system and speakers. It’s a microphone that measures the sound quality of unassisted sound; those measurements are used to determine the corrections.

There’s one other TV sound problem they’re trying to correct: that of varying loudness levels. This has actually been addressed legislatively through the CALM law that says that ads can’t scream any louder than the rest of the programming. But that only applies to a given channel. Different channels may have different loudness levels. Their TotalVolume solution is aimed at “equalizing” the volume of different channels.

That last bit actually has another application of interest to me. Because my sound goes through an oldish amplifier with a manual volume knob, I find I’m constantly getting up to adjust when changing from one or another movie on Netflix or between audio channels like Pandora, soma-fm, or my local radio station’s stream. I suppose I would be thankful if that getting-up process were the only exercise that got me off the couch, but it’s not, so I’d love some equalization in the laptop. And it is something dbx-TV could do, perhaps in the future. But there’s no specific plan for it yet. Oh well… I can hope…

Channels

Computers. Consumer Electronics. Embedded.

 
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