Loudspeakers - how?

[Beedster]

40 minutes ago, Steve Browning said:

It's fascinating isn't it?

Many moons ago I had an Altec loudspeaker that needed reconing. It was an insurance job and so I took it to the chap for the work. He asked if I wanted a generic cone or the proper Altec one. I made the schoolboy error of suggesting there would be no difference and then spent the next 90 minutes listening to him tell me why that wasn't so!!

Yep, fascinating is certainly the word, and the idea that there's no such thing as sound until it meets an ear/brain system stands as a wonderful metaphor for so many other things humans tend to argue about

[leftybassman392]

12 hours ago, Beedster said:

Great thread

Psychoacoustics is where the idea of audio objectivity disappears, as has been nicely out above. If a speaker was plugged into an amp in the woods, turned up to 11, but no-one was there to hear it, would it even have made a sound.......

Some would say that there is no spoon speaker.

[Chienmortbb]

13 hours ago, Beedster said:

Great thread

Psychoacoustics is where the idea of audio objectivity disappears, as has been nicely out above. If a speaker was plugged into an amp in the woods, turned up to 11, but no-one was there to hear it, would it even have made a sound.......

Chaos theory says that if the oft quoted butterly was directly in front of the speaker, a sunami would hit Japan soon after.

Edited September 2, 2020 by Chienmortbb

[Beedster]

The false fundamental idea appears a clear example of how technology fool's the brain, in fact, in real terms I guess it's an example of VR? Not sure how accurate my thinking is, but I'd assume that throughout millions of years of evolution, any given series of harmonics wouldn't have been heard without the fundamental being there somewhere, even if it was below the threshold for hearing (it had to be there to have generated the harmonic series in question). So our brains evolved to recognise, and then to predict the presence of the fundamental from the harmonic series. And as we can now produce those harmonic series with the aid of tech, we are in fact tricking the modern brain into hearing something that isn't there because our ancient brains learned that it was a reliable prediction? Are there any other similar acoustic phenomena? 

[missis sumner]

Have you ever thought about how magnetic tape works?  Wow!  How do you get that sound down in + and - ?

[leftybassman392]

54 minutes ago, Beedster said:

Are there any other similar acoustic phenomena? 

Well, there's our ability to locate multiple sound sources in 3d space with our eyes closed ( a phenomenon that is exploited by a recording technique called binaural recording)...

[Stub Mandrel]

1 hour ago, missis sumner said:

Have you ever thought about how magnetic tape works?  Wow!  How do you get that sound down in + and - ?

It's not digital... there is an ultrasonic bias signal mixed with the audio signal that makes all the magnetic domains jiggle about. During silence, all the domains average to zero. At other times the audio affects the net alignment of domains so the final signal is proportional to the audio (ignoring frequency dependent effects that are processed out). This means the signal can be read back with no more than a simple coil that creates an electrical signal as the magnetic field changes.

[missis sumner]

34 minutes ago, Stub Mandrel said:

It's not digital... there is an ultrasonic bias signal mixed with the audio signal that makes all the magnetic domains jiggle about. During silence, all the domains average to zero. At other times the audio affects the net alignment of domains so the final signal is proportional to the audio (ignoring frequency dependent effects that are processed out). This means the signal can be read back with no more than a simple coil that creates an electrical signal as the magnetic field changes.

Magic!

Then how do compact discs work ?

[Bill Fitzmaurice]

https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio

[Stub Mandrel]

2 hours ago, missis sumner said:

Magic!

Then how do compact discs work ?

Fairy dust.