DIY Perks video: DIY Surround Sound... USING LASERS!

[Hg201]

 

[musicisair]

The laser transmission is pretty neat. Do you think these speakers will perform well?

 

[musicisair]

He talks about how he manages time alignment of the center channel, by putting the tweeter on top of the mid woofer. But then he mounts the woofer above the TV, far above anyone's listening position, likely putting every listener in an null at some frequencies.

Actually, all speakers appear to far above the listening position, and not angled at the listeners. The design and build seems amazing, but the placement seems problematic.

 

[karrtoons]

It's like r/TVTooHigh but for speakers


edit: r/speakerstoohigh already exists .. heh

https://imgur.com/pbB9JA4

 

[tmtomh]

Agree about the center speaker being too high - but his time-alignment point about center channel tweeter and mid is valid: he says the goal is to keep them aligned horizontally off-axis and his vertical mounting design does that.

Regardless, it's a small issue in context - the core idea that he executes here is genius, regardless of how feasible it might or might not be for most folks. Great entertainment, great proof of concept, and great ingenuity, IMHO.

 

[musicisair]

Agree about the center speaker being too high - but his time-alignment point about center channel tweeter and mid is valid: he says the goal is to keep them aligned horizontally off-axis and his vertical mounting design does that.

EDIT: never mind my comment below. I misunderstood/misread.

-- original comment--

I was thinking that since the center channel is mounted horizontally (long ways), and placed far above the listening position, it would put all listeners at every possible seated listening position vertically off-axis. And since the tweeter position doesn't help mitigate the vertical off-axis response there is a good chance they'll find themselves in a null. Maybe a super steep XO slope mitigates this (in which case off-axis nulls in any direction aren't much of a problem).

Am I off(-axis ) in my thinking here?

 

[voodooless]

The YouTube channel DIY Perks did a fun little creative project in which he not only made some interesting DIY active speakers, but also fitted them with an interesting way of delivering audio to them: via wireless toslink!

The TLDR: replace the Toslink transmitter with a laser diode and fit the room with mirrors so that you direct the laser beam back into a standard spdif receiver at the speaker with the dust cover removed. Pretty cool

 

[AnalogSteph]

Really neat, although I do wonder where the volume control is. If you wanted super low latency it could also be done with FM in the analog domain like @pma's project:

Analog audio signal transmission via optical fibre (with test files)

Analog audio signal transmission via optical fibre Intro Though contemporary individual SOTA audio sources (DACs) and preamplifiers and power amplifiers are at the parameters level that any improvements remain inaudible, after the components are interconnected via shielded or coaxial cables...

www.audiosciencereview.com

 

[alex-z]

The laser portion of the project is extremely cool.

My first critique is that using a 4" driver + transmission line for bass extension isn't great. It will play deep but with significant group delay and SPL limitation, for similar cost and total build size you could do a bass reflex 6" instead.

The second thing is claiming that HDMI audio extractor as lossless is misleading. While it does bit-accurate DTS and Dolby Digital decode, those are lossy and old formats, often noticeably worse than Dolby Digital Plus, Dolby True HD, DTS HDMA, etc.

 

[MCH]

This solves the wiring problem in the 5.1 i was planning to build and i was struggling with + gives a use to a 8 channel 4x toslink board i built some time ago. Genius! just feel ashamed for not thinking about this before, specially the trick of the mirrors fixed to the ceiling....

 

[goryu]

genius...

 

[MKreroo]

Does the plastic cover diffuse light have any impact on the signal? I imagine there might be some (not all the laser is entering the receiver?) but I don't have much understanding in how data is transmitted in optics.

 

[tmtomh]

Does the plastic cover diffuse light have any impact on the signal? I imagine there might be some (not all the laser is entering the receiver?) but I don't have much understanding in how data is transmitted in optics.

It's a good question. But since he apparently experienced no dropouts, stutters, clicks, or other issues, it would seem that it works fine. Presumably the diffusion is relatively minor.

 

[goryu]

similar:

Go Wireless With This DIY Laser Ethernet Link

Most of us have Ethernet in our homes today. The real backbones of the Internet though, use no wires at all. Optical fibers carry pulses of light across the land, under the sea, and if you’re…

hackaday.com

 

[MCH]

Does the plastic cover diffuse light have any impact on the signal? I imagine there might be some (not all the laser is entering the receiver?) but I don't have much understanding in how data is transmitted in optics.

The laser might be more powerful than the stock led. He didn't mention it, but the question is if the transmitter he uses has juice enough to power the laser or if he is using a different supply to the laser. Toslink transmitters have 3 pins; GND, VCC and the signal pin. The led is always when there is no signal. I don't recall if he explains how he achieved to operate the laser like that, and his lasers have only two cables..... You might need need an additional power line and a sort of MOSFET triggered by the signal to get a strong output, no idea.

 

[RickS]

Seems cool, but what happens when the laser gets blocked? For that matter, no vision safety concerns?

 

[musicisair]

Seem cool, but what happens when the laser gets blocked? For that matter, so vision safety concerns?

Someone didn't watch the whole video.

He reflects the beams along the ceiling.

 

[RickS]

Someone didn't watch the whole video.

He reflects the beams along the ceiling.

More like not at all!

Sound like a mancave feature. My wife would hate it.

 

[musicisair]

More like not at all!

Sound like a mancave feature. My wife would hate it.

It's not absolutely horrible. Its uses a bunch of tiny articulating mirrors mounted on the ceiling. Like this:

 

[RickS]

It's not absolutely horrible. Its uses a bunch of tiny articulating mirrors mounted on the ceiling. Like this:

View attachment 415508

Yep, hate