Quantcast
High frequencies - Gearspace.com
The No.1 Website for Pro Audio
High frequencies
Old 30th January 2009
  #1
Lives for gear
 
Schaap's Avatar
 
🎧 15 years
High frequencies

After a discussion we did a little experiment with high frequencies that most people cannot hear.
Hightones


Henk
Old 30th January 2009
  #2
Lives for gear
 
🎧 10 years
Hi!

What did you hope to find out and what did you find out?


/Peter
Old 30th January 2009 | Show parent
  #3
FAT
Gear Maniac
 
🎧 10 years
In recording - very high frequencies intermodulate with lower high frequencies. Gotta record and reproduce them right - otherwise everything will sound like crap.
Old 30th January 2009 | Show parent
  #4
Lives for gear
 
Schaap's Avatar
 
🎧 15 years
Quote:
Originally Posted by Audiop ➑️
Hi!
What did you hope to find out and what did you find out?
/Peter
Hi Peter,


Basically:

1. It seems that if one cannot hear indivudal high frequencies, together
those freq's can give a tone or sound that one can hear.

Given that eg., if you boost or shelf the eq from 18kHz (or bit lower) to
give some 'air' it could be that you enhance the sound in
the high spectrum at lower frequencies which are more noticeable - just a hypothese.
On the other side there are people that persistent claim to cutoff all above 16-18 kHz
because most people on the earth are not able to hear it.

2. If in this example a sinus of 22 kHz affects the sound in a way
(and you should try even higher freq's!) So if you want to record
'true as your source' the 44.1 kHz falls short, given you use
a mic that captures those high frequencies.

Anyway, some 'food for thoughts'
Old 30th January 2009 | Show parent
  #5
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by Schaap ➑️
1. It seems that if one cannot hear indivudal high frequencies, together
those freq's can give a tone or sound that one can hear.
Hi!

Well, the thing is that the level (SPL) of ultrasound needed to give audible intermodulation products in the air is so high it will not happen with normal music.

The files you prepared can not be used to investigate this since the nonlinearity in the electronics and speakers will produce IMD that will give a false result or impression of the test.

What you need to do to investigate this is to play back single sines in differerent chanells and speakers to avoid intermodulation in the playback chain.

I have done that and could hear nothing.

I used a 23kHz and 24kHz sine played back via two chanells at reasonable level and the result was dead silent.

I have confimred that I can hear up to 21.5khz at high levels and I have measured the speakers as being more or less flat up to 40khz.


/Peter
Old 30th January 2009 | Show parent
  #6
Gear Guru
 
Ethan Winer's Avatar
 
🎧 15 years
Quote:
Originally Posted by Audiop ➑️
the level (SPL) of ultrasound needed to give audible intermodulation products in the air is so high it will not happen with normal music.
Yes, when IM products are created it happens inside the ears. But the music doesn't have to be terribly loud to generate IM products. I can hear IM tones when I play the glockenspiel in a local orchestra. If I play a minor third or major second etc on high notes loudly, I can clearly hear the low frequency difference tones generated in my ears. I doubt people in the audience hear that though.

--Ethan
Old 30th January 2009 | Show parent
  #7
Lives for gear
 
Schaap's Avatar
 
🎧 15 years
Quote:
Originally Posted by Audiop ➑️
Well, the thing is that the level (SPL) of ultrasound needed to give audible intermodulation products in the air is so high it will not happen with normal music.

The files you prepared can not be used to investigate this since the nonlinearity in the electronics and speakers will produce IMD that will give a false result or impression of the test./Peter
OK. But when you do a close recording of an instrument with lots of harmonics, cymbals, percussion etc. you pick up quite a lot of high frequencies> 15 kHz so I wonder if the electronics and speakers may be a part then of the reproduced sound, what you hear.

Another thing(maybe related) what puzzles me is that when one put 'air' EQ, say a shelfboost from 15 kHz, on a recording/mix in general one notices a different perception even if they're not able to hear a 15 kHz sinus.
Old 30th January 2009 | Show parent
  #8
Lives for gear
 
gwailoh's Avatar
 
🎧 15 years
I can hear the dog whistle at the end of Sgt. Pepper. Does that count?
Old 30th January 2009 | Show parent
  #9
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by Schaap ➑️
OK. But when you do a close recording of an instrument with lots of harmonics, cymbals, percussion etc. you pick up quite a lot of high frequencies> 15 kHz so I wonder if the electronics and speakers may be a part then of the reproduced sound, what you hear.
Yes, most electronics and speakers are nonlinear enough to give intermodulation products which should not be there. Typically electronics have increased distortion towards higher frequencies. That's one reason to keep ultra sound OUT of the recording. Most of that is taken care of by the CD format brickwall filter but we can possibly expect problems with SACD, DVD-A and the equivalent.

Quote:
Another thing(maybe related) what puzzles me is that when one put 'air' EQ, say a shelfboost from 15 kHz, on a recording/mix in general one notices a different perception even if they're not able to hear a 15 kHz sinus.

Likely there will be a small EQ effect below that point that is audible even if a person can not hear 15k. The shelf is a shelf and not a brickwall filter and we can often hear small shifts of much less than a dB in the band that we actually hear.


/Peter
Old 31st January 2009 | Show parent
  #10
FAT
Gear Maniac
 
🎧 10 years
Quote:
Originally Posted by Ethan Winer ➑️
Yes, when IM products are created it happens inside the ears. But the music doesn't have to be terribly loud to generate IM products. I can hear IM tones when I play the glockenspiel in a local orchestra. If I play a minor third or major second etc on high notes loudly, I can clearly hear the low frequency difference tones generated in my ears. I doubt people in the audience hear that though.

--Ethan
Ethan, you're too busy looking at the audience's boobs to care about what they're hearing when you play your little glock.
Old 31st January 2009 | Show parent
  #11
Gear Guru
 
Ethan Winer's Avatar
 
🎧 15 years
Do you mean boobs who are in the audience, or boobs on the women in the audience? That's a big difference you know!
Old 31st January 2009 | Show parent
  #12
Gear Guru
 
theblue1's Avatar
 
🎧 15 years
This thread seems to be going south quickly...


heh


With re audibility of overtones -- existing testing supports existing theory: if your ear cannot perceive a given fundamental, it will not be able to perceive an overtone at that frequency. (This refers to free air audio -- not bone conduction, which is a whole 'nother can of worms but, happily, one most of us don't have to worry about too much unless we're also developing bone-conduction hearing aids.)
Old 1st February 2009
  #13
Gear Maniac
 
rashman's Avatar
 
🎧 15 years
and the final verdict is?

in the end are these ultrasonic frequencies important or not? I'm concerned about making the decision to stay 44.1 or going higher. I've analysed many highend records and they are mostly cut steeply above 16 to 18k.
Old 1st February 2009 | Show parent
  #14
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by rashman ➑️
in the end are these ultrasonic frequencies important or not?
There are several studies that tells us no, UHF is not audible other than when such inaudible frequencies cause audible distortion in imperfect electronics and speakers. There are no (to me) known studies that indicates that we can hear +20k information.

Quote:
I'm concerned about making the decision to stay 44.1 or going higher. I've analysed many highend records and they are mostly cut steeply above 16 to 18k.
Sample rates is another thing actually since different filters and aliasing can cause audible effects. Some converters simple perform better at higher rates.


/Peter
Old 4th February 2009 | Show parent
  #15
Gear Maniac
 
rashman's Avatar
 
🎧 15 years
thanks Peter. Very useful.
Appreciated.
πŸ“ Reply

Similar Threads

Thread / Thread Starter Replies / Views Last Post
replies: 59 views: 16540
Avatar for matt9b
matt9b 26th March 2016
replies: 894 views: 287371
Avatar for ardis
ardis 24th June 2021
Post Reply

Welcome to the Gearspace Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…

Forum Jump
Forum Jump