Jump to content
IGNORED

The Audiophile Challenge


Dragon

Recommended Posts

 

from what i gather the beat frequency will actually sound like tremolo effect, you won't magically get a tone at that frequency.

yes you do, you'll only hear a tremolo if the difference between the 2 freqs is below the audible range...

 

EDIT: Doing it 'properly' and you do indeed get creation of the exact pure sine waves at the difference of the other frequency you modulate it with. Physics/Maths wins !

good to know it works! :thumbsup: what soft are you using?

 

now i'm confused, i do what? you don't get a third tone out of combining two sines, you just get a frequency of a tremolo out of that difference. is that what you mean?

 

here's a file where i combined a 30 and 31khz tones. there's nothing else on the spectrum and naturally you can't hear anything.

1.flac

Link to comment
Share on other sites

I'm not sure how you do it on other audio editors but in Cool Edit/Audition I when I mix-paste'd the two waveforms I had to set it to 'modulate' rather than 'overlap', which summed the amplitude of each sample. Otherwise (like you say) you just end up with two high/inaudible pitched sine waves happily playing together without any beating/interaction

Link to comment
Share on other sites

now i'm confused, i do what? you don't get a third tone out of combining two sines, you just get a frequency of a tremolo out of that difference. is that what you mean?

you do get a second sine yes, if the difference is up to about 40hz you get an LFO which you perceive as a tremolo but if the difference is over 40hz you start hearing a tone... same happens with a sequence of noise clicks, just keep increasing the frequency of that sequence and over about 40 you'll get a tone, at 440hz you get an A4, etc...

 

There are two types of combination tones: sum tones whose frequencies are found by adding the frequencies of the real tones and difference tones whose frequencies are the difference between the frequencies of the real tones. "Combination tones are heard when two pure tones (i.e., tones produced by simple harmonic sound waves having no overtones), differing in frequency by about 50 cycles per second %5BHertz%5D or more, sound together at sufficient intensity."%5B2%5D

Combination tones can also be produced electronically by combining two signals in a circuit that has nonlinear distortion, such as an amplifier subject to clipping or a ring modulator.

Edited by THIS IS MICHAEL JACKSON
Link to comment
Share on other sites

aren't you doing a bit of an AM/FM synthesis instead of emulating that beating thing when you do the modulate thing? the idea of beat frequency is simply two frequencies arriving at the same place. i do get the beating effect when i mix two sines in the audible range in the same manner.

http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/beat.html

Link to comment
Share on other sites

aren't you doing a bit of an AM/FM synthesis instead of emulating that beating thing when you do the modulate thing?

Very possibly, yeah I think you're right !

 

i_have_no_idea_what_im_doing_meme_640_21

Link to comment
Share on other sites

i must admit i'm also confused but lookie here, from the same page you linked eugene:
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/london.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/subton.html#c1

Edited by THIS IS MICHAEL JACKSON
Link to comment
Share on other sites

i'm confusing these examples of beat effect with the intermodulation distortion because what i learned about IMD was that the new frequencies are are generated at summing and subtracting the difference between the 2 tones to the original tones... you have 270 and 275 MHz, the difference between them is 5 Mhz, so the new frequencies will be at 265 Mhz and 280 Mhz... but at the same time in this wiki page it also says that the resulting frequencies are the sum and difference between the 2 original tones, which would lead to 5 Mhz and 545 Mhz... :scratches head:
800px-RF_Intermodulation_at_280_MHz.jpg

Edited by THIS IS MICHAEL JACKSON
Link to comment
Share on other sites

while we're at it there's also this cool effect which in fact is the same effect, when you mix 2 white noise sources with a time difference you'll get a frequency with the same period as that time difference, eg. Δt=1ms ---> f=1kHz

it doesn't happen only with white noise it also happens with a complex signal like a song or anything...

Link to comment
Share on other sites

while we're at it there's also this cool effect which in fact is the same effect, when you mix 2 white noise sources with a time difference you'll get a frequency with the same period as that time difference, eg. Δt=1ms ---> f=1kHz

it doesn't happen only with white noise it also happens with a complex signal like a song or anything...

well, duh, that's basically how a phaser/flanger works... :facepalm:

Link to comment
Share on other sites

Haha, was thinking that :) (though still, you mentioning about a further frequency being generated is interesting - I'm wondering if that's the most noticeable component to the ears rather than the phasing ?)

Link to comment
Share on other sites

Haha, was thinking that :) (though still, you mentioning about a further frequency being generated is interesting - I'm wondering if that's the most noticeable component to the ears rather than the phasing ?)

:brainknot: lol, not sure what u mean, i mentioned a further frequency regarding IMD and combination tones, not phasing... :) Edited by THIS IS MICHAEL JACKSON
Link to comment
Share on other sites

Will be very interested to hear the results of these blind tests. I highly doubt we can discern a difference even if we think we can Intrigued

 

 

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

I promise I'll get to this!

 

Medical thing seems to have been a false alarm thankfully, but I worked 6 days this week (today's the last one) not counting wrk I have to do from home tomorrow, and am generally burned out.  But I have a short week next week so I'll be rested up and fresh on Monday or Wednesday.

 

Your physical and mental state have a much bigger (real, researched and demonstrated although I'm not going to bother digging up citations) effect on how you perceive sound than mp3 compression does, so if I'm going to do this I want to be rested.

 

That's also another reason why, on the listening end, these debates are pretty moot.  Not getting enough sleep makes a bigger difference than good lossy compression does.  Moving your head an inch to the right has a bigger effect than lossy compression.

Link to comment
Share on other sites

Hell, if I have a laptop in front of m when I'm listening to music on a stereo system, whether or not the lid is open has a bigger effect - actually it has a really big effect, the reflections from the back of the laptop screen really mess up the center of the stereo image, especially low mids.  More than m3 does, mp3 mostly just kills transients.  But hell, a couple months ago I had a spider plant above one of my speakers and one of the runners dropped down so it was hanging in front of the midrange driver, and that had as much of an effect on transients and high frequency response as I hear in a well compressed mp3 (except since it was only one speaker it also messed up the imaging and made all of the high frequency content sound like it was panned a bit to the opposite side).  Which is to say, totally obvious if you're listening carefully but also so subtle that in practice it's irrelevant.

Edited by RSP
Link to comment
Share on other sites

I think a more interesting discussion would be whether the audiophile industry is, in fact, exploiting people on the autism spectrum. 

 

When I was looking for one of the links I posted earlier I happened to also find out about sensory processing disorder, which I'd never heard of before somehow.  From what I've read about it since, it's actually pretty common the most ambitious estimates are something like 20% of humans qualify for the label to some degree, although that seems absurdly high), and it's basically a neurological difference that makes some people much more acutely aware of subtle differences in sensory input, especially sound.  Not, like, extra acute senses - everyone who doesn't have an actual sensory impairment can detect the same stimulus least a bit - just an extremely heightened neurological sensitivity to and awareness of it.  There's a very high rate of comorbidity between SPD and autism spectrum disorders (those Polynesian navigators that people have been talking about lately, for example).  There's also a very high comorbidity between autism spectrum disorders and OCD spectrum disorders.  That seems like a perfect storm for selling people expensive snake oil.

 

Anecdotally, I worked at a pretty serious used record shop for about 7 years and in my experience there at least, being an audiophile seemed to have a pretty high comorbidity with ASD.

 

I don't know, I find stuff like that pretty interesting and this has also made me feel a bit more sympathetic to audiophiles and even less sympathetic to the companies that sell audiophile bullshit.

 

 

 

I also found a link to an Amazon seller who was hawking $13,000 audiophile HDMI cables but f course I didn't bookmark it. 

 

EDIT: the HDMI cable might have been linked somewhere in the hundreds of comments on one of the articles I linked to the other day, actually, but I've got to get ready for work so I can't check now.  It's worth trying to find, though. The comments on the Amazon item page were gold.

Edited by RSP
Link to comment
Share on other sites

Beteen working at that record store and having had mostly musician and artists for friends since high school I've known a lot of nutters, so this is the sort of thing that I think about pretty regularly.

Link to comment
Share on other sites

 ...but the difference between 320kbps mp3 and CD audio is night and day.

 

Your physical and mental state have a much bigger (real, researched and demonstrated although I'm not going to bother digging up citations) effect on how you perceive sound than mp3 compression does, so if I'm going to do this I want to be rested.

 

That's also another reason why, on the listening end, these debates are pretty moot.  Not getting enough sleep makes a bigger difference than good lossy compression does.  Moving your head an inch to the right has a bigger effect than lossy compression.

 

i see progress.

Link to comment
Share on other sites

  • 4 years later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.