TOSLINK was developed in the early 1980s as a simple interface for sending digital audio over fiber optic cables, and despite its age, is still featured on plenty of modern home entertainment devices. As demonstrated by [DIY Perks], this old tech can even be taught some new tricks — namely, transmitting surround sound wirelessly.
Often, a TOSLINK stream is transmitted with a simple LED. [DIY Perks] realized that the TOSLINK signal could instead be used to modulate a cheap red laser diode. This would allow the audio signal to be sent wirelessly through the open air for quite some distance, assuming you could accurately aim it at a TOSLINK receiver. The first test was successful, with the aid of a nifty trick, [DIY Perks] filled the open TOSLINK port with a translucent plastic diffuser to make a larger target to aim at.
The rest of the video demonstrates how this technique can be used for surround sound transmission without cables. [DIY Perks] whipped up a series of 3D printed ceiling mirror mounts that could tidily bounce laser light for each surround channel to each individual satellite speaker.
It’s a very innovative way to do surround sound. It’s not a complete solution to wiring issues—you still need a way to power each speaker. Ultimately, though, it’s a super cool way to run your home theater setup that will surely be a talking point when your guests notice the laser mirrors on the ceiling.
We’ve seen some other stealthy surround sound setups before, too.
[Thanks to jenningsthecat for the tip!]
Hope that pretty lights it won’t atract JDAMs.
And why you didn’t mention the hobbit house where you can use those speakers?
9 months old video…
Hello!
One downside of long transmission line speakers: building up the resonance to get the sound pressure takes time, which creates lag, which is the very thing that he’s trying to avoid, and it kills the transient response (e.g. drum hits).
It’s great for those movie effects with a long bellowing bass, because you don’t care whether the constant droning comes 300 ms late, but for listening to music it’s just going to muddle it completely.
Also, killing the resonance takes time, so when the speaker stops vibrating the entire tube is still ringing with the sound for tens of cycles before the sound goes away. You could mitigate that effect by adding dampers, but then the resonance won’t build up as strongly and the bass becomes muted.
In other words, making a tiny driver sound big by adding a huge resonating volume to it is a gimmick.
For the sound to reach the speakers with a 300ms delay, the source had to be around a hundred thousand km away…
You will need a pretty powerful laser, and play from (or to) somewhere in space. A third of the distance to the moon, give or take.
That was in terms of the resonance. At 30 Hz one cycle takes 33 ms and if it takes 10 cycles to build up the resonance, then the sound pressure is going to reach peak 330 ms later.
Though sound travels at 340 m/s so technically just 102 m away would be consistent for 300 ms.
So the effect is like a big stadium. The mid and high range speakers are right in front of you, and the subwoofer, at least in terms of peak sound pressure, is a football field away from you.