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When I was a high schooler, I built a system in my room. Like this amazing thing, it was something I felt needed to stay intact. I can identify with the guys
by ddingus 3y ago
When I was a high schooler, I built a system in my room. Like this amazing thing, it was something I felt needed to stay intact. I can identify with the guys last wish and also know for sure it won't ever happen.
Honestly, it was OK. We did not have a lot growing up and so I had scrounged this and that often building things custom to take advantage of the room and passive acoustics to get good sound.
I, and friends and family, listened to a lot of music on it.
Then I did something one day that would turn out to be special!
Just for kicks, I wondered whether recording using the same speakers that would play the recording back would sound good.
Turns out yes! It was a little like a hologram. If you played those recordings in my room, you would hear the house! Mom cooking in the kitchen, living room TV, complete with CRT wine, in the living room, people talking...
It was all there! And one could place the sounds as if they were really happening. Listening in, say the middle of the night, was dramatic. With eyes closed, it was like midday. Hard to tell otherwise.
And those recordings only worked on that system, in that room.
Today, I bet software would tease out what I did on a wider range of listening scenarios. But back then, some considered it magic, and only in that room.
So when I left home, I left it all and some tapes and encouraged anyone wanting to hear family life from some years ago to go and listen before it all gets torn apart.
My mom sold the house and that was the end of an era. Sadly, the tapes have been lost too.
All I know is you can use a capable preamp to record through your speakers and when that recording is played on that system, it will be magic!
- pizza 3y agoThat's an amazing idea..
- ddingus 3y agoTurns out it was! But, the amazing outcome was limited to playback on that system. Playback on another one sounded good, even better than mine, but the illusion I described was not there.
- pizza 3y agoI guess it must be a combination of getting both the frequency response and phase response just right. It won't be any where near as good but you might be interested in Room Eq Wizard too
- ddingus 3y agoIt is the phase relationships for sure! Those are what places everything. Well, most everything. Frequency response changes do it too. Front/Back for example. Frequency response curves are very different. If the overall EQ is close, it all seems to work. But moving stuff has a tighter tolerance from what I remember.
- deleted 3y ago[deleted]
- kenhwang 3y agoIt's like a multi-speaker version of binaural recordings! Binaural recordings already have very realistic playback on headphones. So I'd imagine using multiple speakers would be a trip for everyone in the room. I assumed you flipped the speakers around to record?
- ddingus 3y agoNope. Left them in position. Moving things tends to break the illusion.
- Nition 3y agoWhat a cool idea. I'm really surprised that using big speakers as microphones still let you pick up the CRT whine way up at nearly 16KHz! I would have thought you'd be mostly picking up bass. I guess the size of a tweeter at least, isn't that much bigger than what's in a dynamic microphone.
- ddingus 3y agoI had smaller 3" drivers mounted high, near the ceiling. In the cabinet with them were even smaller tweeter type, dome shaped that I am sure picked up the high end. I am not sure I used the big drivers at all for recording. Hard to remember.
- kevindamm 3y agoReminds me of how you can get a mold of your ears made to put over a mic, then the recordings sound more like they're coming from outside your ears when you hear them even with in-ears.
- flyinghamster 3y agoBinaural recordings can also be made with small in-ear mics (be careful, they'll pick up clicks from your eardrum when you swallow), or a close approximation by clipping omnidirectional mics to your glasses. Or, if you're made of money, there are purpose-built dummy heads like this: https://www.neumann.com/en-en/products/microphones/ku-100/ https://www.neumann.com/en-en/products/microphones/ku-100/
- tomcam 3y agoMagical! Never thought I’d apply that term to a Hacker News post
- smallhands 3y agorecording through the speaker!! please explain how is that possible!!!!
- kadoban 3y agoSpeakers and a certain kind of microphone are exactly the same thing at the basic level. Sound hitting the diaphram (the bit that moves to produce sound) of a speaker will cause a voltage to be produced on the speaker wires that can be recorded.
- HelloNurse 3y agoMost types of speaker are a microphone, they just need to be wired up correctly (hence the mention of a "capable preamp") to be used as one. For example, a piezoelectric device that deforms when driven by an electric current produces a little current when deformed by external forces.
- ddingus 3y ago"Capable" As in capable of amplifying the low signal from the speakers reasonably without too much noise. There is likely a proper term I do not know.
- ddingus 3y agoLook at dynamic microphones. Check this out: (this is where I got the idea of recording through speakers) In 8th grade, I took apart a dynamic microphone I had picked up from radio shack. It was essentially a tiny speaker! Naturally, I went ahead and connected it to the headphone jack of a portable cassette recorder and... Heard some of the BEST sound I had ever heard out of small electronics! It was not loud, but it was detailed and full so long as one held the mic right against the ear. I bought another one and mounted both of them inside some hearing protection type ear covers, essentially turning them into a sort of weird headphone. Later on, a friend showed me a Walkman type radio / cassette player and the little open air type speakers it came with looked a whole lot like the dynamic mic "speakers" did and had a similar sound too. I had come close to producing open air type listening gear on my own. My first attempt at stereo listening failed because I just did not have a great head mount. Went with the ear protection gear because that fit well and did make the most of the great, but somewhat quiet sound the little plastic cones in the cheapo dynamic mic could deliver. Had I been able to come up with a suitable mount, it was extremely likely I would have ended up with two small speakers resting right on my ears Walkman style. In any case, that is when I realized speakers can be microphones and that lead up to the point of discussion here now.
- antongribok 3y agoReading this for some reason reminded me of the Virtual Barber Shop: https://m.youtube.com/watch?v=IUDTlvagjJA https://m.youtube.com/watch?v=IUDTlvagjJA (Use headphones and close your eyes.)
- ddingus 3y agoThat is a great soundscape
- ncr100 3y agoTurning a cute tragedy of an obsessed man into a significant eavesdropping technology exploit and privacy nightmare... Peak hacker news discussion!
- ddingus 3y agoI identified with that guy having made something similar that would only work where it was made. I am not sure many of us find ourselves having done that.