There's Life Above 20 Kilohertz!

[bcgood]

Here's an article I ran into for the first time tonight.

I enjoyed reading it, perhaps you will to.

There's life above 20 kilohertz! A survey of musical instrument spectra to 102.4 kHz

[Audiop]

Not exactly news.. the article or the content. It has been mentioned many times before on GS (both the article and the content).

Anyway I'm going into town to load up on popcorn.. assuming this will be another heated 38 pages thread!


/Peter

[dcollins]

Originally Posted by Audiop

Not exactly news.. the article or the content. It has been mentioned many times before on GS (both the article and the content).

Anyway I'm going into town to load up on popcorn.. assuming this will be another heated 38 pages thread!

I hope not.


DC

[bcgood]

What's with these homies dissin my thread?

Why do they gotta front?

[Audiop]

Sorry bc, I did not mean to be disrespectful, it's just it really is old news and have been debated to death in several threads the latest time.

However I do like the neutral position the author of the article takes which is in contrast to several other authors who seems to want to prove something to give weight to their beliefs.

Yes, instruments produce energy in the area above the audible range. Typically the level is very very low and checking the equal loudness curves makes you realise that it's not likely to be of any significance.

I use high bandwith gear myself but becasue that often translates to higher fidelity in the last audible octave, not the ultra stuff which is inaudible.

Remember, there are lots of studies that show the insignificance of ultrasound in audio and the few who claim to prove the opposite is very questionable and has yet to be repeated. I've also seen people with a possible interest involved in those studies which again is very questionable.

Again, sorry if I came across as a dizzing homie!


/Peter

[bcgood]

Oh no worries, just having some fun with Weezer lyrics 2 C if anyone would catch it since DC mastered their last album.

I'm still open to this one either way. I would love to sit down and do a real test sometime as I feel I have the ears for it. Maybe someday I'll buy all the gear I've ever been interested in, even in the slightest; when I'm a zillionaire....

Yea, that's the ticket!

[Audiop]

I have an open mind but I also use rational and logic when setting priorities..

Speculation is fun sometimes and to some degree but in the end I want to see something with substance.


/Peter

[kjg]

don't feed the trolls, Peter

now, where's that ultrasonic heterodyning thread?

[Audiop]

Originally Posted by karyoky****

hi,

well, the fact that high frequency sounds exist is obviously of some significance.

Yes, for bats and other animals.

everything in God's creation has some significance and purpose.

I think that is a disucssion we better pass on.. these discussions tend to get dirty enough without mixing religion and politics.


/Peter

[Table Of Tone]

That'll be the air we breath!

[doorknocker]

There's Life Above 20 Kilohertz........





...if you're under 20!!!!

[Lagerfeldt]

Heh

I can't hear anything above 19 kHz.

[Table Of Tone]

Originally Posted by Lagerfeldt

Heh

I can't hear anything above 19 kHz.

Hello mate!

18Khz for me but I'm an old barsteward!

[lerone]

I believe thats where the Martians live, or so I'm told.

[doug hazelrigg]

Sheet, I have trouble hearing 16 khz, unless it's cranked

[bcgood]

One thing that I really did think a lot about while reading that article is a symphony concert I went to a month ago. It was in the Mondavi Center which is an extremely nice acoustic space. I loved how smooth the sound was, no grain at all just huge 3D smoothness surrounding me. It would be so great if someday we can closely re-create this type of sound to the listener via technology and engineering.

[dcollins]

Originally Posted by karyoky****

hi,

as i said.

If there were mic, speakers or hair-cells for >20kHz things might be different.

I think it's quite obvious some instruments generate harmonics out to channel three. That's really all Professor Boyk shows there.


DC

[dcollins]

Originally Posted by bcgood

One thing that I really did think a lot about while reading that article is a symphony concert I went to a month ago. It was in the Mondavi Center which is an extremely nice acoustic space. I loved how smooth the sound was, no grain at all just huge 3D smoothness surrounding me. It would be so great if someday we can closely re-create this type of sound to the listener via technology and engineering.

You might have a look at:

AES E-Library: Perceptual Soundfield Reconstruction


DC

[bcgood]

Originally Posted by dcollins

You might have a look at:

AES E-Library: Perceptual Soundfield Reconstruction


DC

Hi Dave, have you ever listened to a properly set up system with speakers for this? I've listened to some nice recordings made with "Fritz" on my studio headphones that sounded nice and realistic but honestly only a shadow, a reflection of the real deal.

[Key]

Originally Posted by bcgood

One thing that I really did think a lot about while reading that article is a symphony concert I went to a month ago. It was in the Mondavi Center which is an extremely nice acoustic space. I loved how smooth the sound was, no grain at all just huge 3D smoothness surrounding me. It would be so great if someday we can closely re-create this type of sound to the listener via technology and engineering.

I believe you can but I do not think it is dependent on ultrasonic content. It is a challenge to get high frequencies to reproduce over loudspeakers in an omni directional manner though. The omni directional polar patter for the majority of the bandwidth and the off axis frequency response I believe are the main factors preventing this kind of realism.

But I have been noticing speaker manufacturers reaching up higher and higher with the frequency response as well as the polar pattern. So maybe they are a couple steps a head of us.

[dax4]

I have only recently begun lurking on GS - I am amazed how much resistance there is to this research. Intermodulation of harmonics is not a sci-fi issue. Take a 40 kHz wave and a 50 kHz wave - they will modulate together to create a wave at their coincedental nodes with a fundamental frequency of their common denominator - this being 10kHz. Audible.

.. I think. But that's why I still listen to analogue. What I hear above all else is harmonic richness.

-~ happy in my ignorance ~-


(maybe someone with an sinewave generator could prove this - create a wave at say 40k then sum in another wave starting at 20k and sweep upwards - in theory nothing audible should pop out ... )

[Key]

Originally Posted by dax4

I have only recently begun lurking on GS - I am amazed how much resistance there is to this research. Intermodulation of harmonics is not a sci-fi issue. Take a 40 kHz wave and a 50 kHz wave - they will modulate together to create a wave at their coincedental nodes with a fundamental frequency of their common denominator - this being 10kHz. Audible.

SO why would you need a chain that records 40kHz to record 10k?

[dax4]

because the 10k only comes after summing the channels

but I just realised - this is the mastering forum - so I am ducking out now, need to do more lurking , sorry ..

[Key]

I guess it depends on the circumstances. But if it is an acoustic sound I believe the summing takes place int he acoustic realm and not the electronic or digital.

[Audiop]

Originally Posted by dax4

I have only recently begun lurking on GS - I am amazed how much resistance there is to this research. Intermodulation of harmonics is not a sci-fi issue. Take a 40 kHz wave and a 50 kHz wave - they will modulate together to create a wave at their coincedental nodes with a fundamental frequency of their common denominator - this being 10kHz. Audible.

.. I think. But that's why I still listen to analogue. What I hear above all else is harmonic richness.

-~ happy in my ignorance ~-


(maybe someone with an sinewave generator could prove this - create a wave at say 40k then sum in another wave starting at 20k and sweep upwards - in theory nothing audible should pop out ... )

Intermodulation only occure if there's significant nonlinearities and the air is not nonlinear enough for this to happen.

If you hear something it will be from the nonlinearities in electronics and speakers.


/Peter

[Audiop]

Originally Posted by Key

I believe you can but I do not think it is dependent on ultrasonic content. It is a challenge to get high frequencies to reproduce over loudspeakers in an omni directional manner though. The omni directional polar patter for the majority of the bandwidth and the off axis frequency response I believe are the main factors preventing this kind of realism.

But I have been noticing speaker manufacturers reaching up higher and higher with the frequency response as well as the polar pattern. So maybe they are a couple steps a head of us.

There are several ways of dealing with this and one could argue the problem is the same with two channel stereo.

One can use directional speakers like cardioids or dipoles or one can use multiple tweeters in a traditional speaker to end up with a more even energy response in the room.

I think todays technology allows for a very realistic reproduction and I'm looking at some options for this right now. I'm going to use 4-6 discrete ambience channels feeding at least two speakers from every channel. One channel will be for height and mounted in the ceiling. Two or three main channels plus aprox. ten ambience channels will never be the norm for reproduced music in the home though.. needless to say..



/Peter

[Table Of Tone]

Originally Posted by doug hazelrigg

Sheet, I have trouble hearing 16 khz, unless it's cranked

Pardon...?

[bcgood]

Originally Posted by Table Of Tone

Pardon...?

[turtlerock]

Originally Posted by Lagerfeldt

Heh

I can't hear anything above 19 kHz.

gee lagerfeldt buy the look of your avatar you have aged TWENTY years since last time i dropped in the forum
no wonder your hearing has dropped a bit !
nice photo btw
err in a non man to man kinda way : )

[Key]

Originally Posted by Audiop

There are several ways of dealing with this and one could argue the problem is the same with two channel stereo.

One can use directional speakers like cardioids or dipoles or one can use multiple tweeters in a traditional speaker to end up with a more even energy response in the room.

I think todays technology allows for a very realistic reproduction and I'm looking at some options for this right now. I'm going to use 4-6 discrete ambience channels feeding at least two speakers from every channel. One channel will be for height and mounted in the ceiling. Two or three main channels plus aprox. ten ambience channels will never be the norm for reproduced music in the home though.. needless to say..



/Peter

You are correct I think. Dipole, Omni, and Cardiod are the way to go. And of course it's not easy to tell what are what by looks alone.

And this imo does not solve a lot of glaring problems. Of course it can be subjective and as you have observed there can always be more speakers.

I personally feel the biggest problem with stereo and realism is a lack of coverage. For me 4 speakers is the minimum to get sufficient coverage and let the illusion take over instead of a recording in front of my face.

Even though I love 4 speakers and see it as a great alternative to 2 I can still pick apart some problems with the illusion and have started using dipolar rears. So I am technically up to 6 or 8 speakers and I am only really going for hoizontal coverage and no height.