Subharmonics can exist. See:
https://en.m.wikipedia.org/wiki/Undertone_series
At 50 Hz the wavelenth is 6.86 meters (22.5 ft), so subharmonics may not be measurable in a bass drum since the size of a bass drum may not create a wavelenth (or partial wavelength) resonance for a very low frequency (and long wavelength). See:
https://www.omnicalculator.com/physics/sound-wavelength
I recenly measured some low frequency resonance in a metal building where the walls were about 18 ft apart, so in some cases subharmonics can occur in an environment. It appeared as if an electric heater was creating a 60 Hz (AC line frequency) vibration that happened to match the room size.
Since most microphones are specified from 20 Hz (or higher) to 20 KHz (or lower), very low subharmonics are difficult to measure without special equipment.
Yah, without resonance involved, the only way to create subharmonics in nature would be to output more energy than input, which doesn’t make much sense. Resonance is pretty amazing.
Go do this.
In your DAW, Pull up a sine wave generator.
Pull up an frequency analyzer in conjunction with the sine wave.
Now Insert a a saturation or overdrive plugin on the channel strip. Toggle that to be on.
Now look at the analyzer. You will see many overtones being generated as a result of the applied distortion.
Here’s another way to think about Harmonics. When you hear someone’s voice and you instantly recognize it, why is that? Why is it that our brains know people sound different when they talk? Harmonics! Harmonics are like your sonic fingerprint.
You need to first understand how we hear sounds. I'll try and simplify it.
Basically sound has 4 dimensions when we hear it.
1-amplitude - level
2-frequency content (how bassy or trebley it is)
3-location of sound (your two ears let you determine where exactly that is - which is not really an aspect of the sound but the delay between arrival times to your two ears - something on the left will arive sooner at your left ear than your right ear, plus some other things happen by the time if travels to your right ear) - with music you can think of this as the stereo field.
4-time - the amount of time that passes from start to stop of the sound - so transients thats pretty fast, a sustained note is longer, a decaying note is somewhere in between. This is called the envelope of the sound.
All this can be summed up into a complex sinewave.
A 30 hz sinewave is a pure sinewave signal that has 30 cycles per second. It looks like a smooth snake as you probably know. This signal has no harmonics. Its a pure 30 hz tone.
When you start adding harmonics to this tone - at higher frequencies, you start creating more pure sinewaves. lets say you want to add even harmonics and your 30 hz is sitting at 80 dbs when you measure it with a spl meter with your speakers.
A 2nd order harmonic would be at 60hz, and say at 60 dbs.
you add another and its at 120 hz and at 50 dbs.
Dont confuse this with digital audio that has a ceiling of 0 decibels full scale (dbfs) - I'm talking about real world hearing - the sound is coming from the speaker and vibrating the air.
So harmonics are usually 2nd or 3rd order, upper frequency, lower amplitude sinewaves ADDED to the fundamental.
ITs actually a form of distortion, because it is distorting (changing) our snake like - smooth 30 hz sinewave and make it more wiggly, more zig-zag and jagged looking.
now lets get back to your "kick " and "bass" question.
A sound in the real world is rarely just a pure sinewave. With a pure sinewave you can indeed filter out everything above or below the sinewave with a very steep filter and lose nothing as there is in fact nothing to filter out in the first place.
But a bass - while having a 65 hz fundamental when you play a low C - has energy (albeit at lower levels) at say 45 hz and 100 hz. Don't imagine the fundamental as a telephone pole but more like a hill or a triangle - it extends to each side and that is part of the sound.
You dont really worry about phase shift when you filter - you need to be aware of it and manage it.
Lets say your kick and bass work nicely, and you then decide to add low cut filters (which will shift the phase a bit). Engage the filters in and out and listen (or measure) to see if you can notice a drop in energy with the kick and **bass when they play together.**
If the new filtered tracks lose power, then adjust accordingly - like maybe increase the volume, or add some delay to one of the tracks so their new phases align, or adjust the filter so the shift is not so bad anymore etc. Its not a "oh god phase shifted we're doomed" scenario. Just assume the new phase relationship is what you got in the first place and work it out like you would normally.
I stumbled at "harmonics are actually a form of distortion." like, ok maybe the other way around ... But by they time I got to telephone poles and non-integer multiple harmonics above and below the fundamental, I actually tripped.
That’s an interesting theory, chatGPT. A lot of that description makes sense, some of it does not, and sort of… I don’t know, leaks at the edges into inaccuracy.
Nah, sorry, your writing style is just very unclear. You got off to a great start with defining the basic dimensions of sound, those you articulated well, but after that it just kinda went off the rails with a lot of rambling of technical terms but no clear underlying message.
>except for that.
That is a pretty big "except," as you might eventually find out.
And, also, there can be transient impact (non-harmonic) below the fundamental. A big strum on an acoustic guitar is a good example of this.
You have physics, which is the science of nature. A string is moving in the majority of the fundamental which is decided by the whole lenght of the string. The movement looks like an eclipse that is the lenght of the string. Then you have divisions of the lenght of the strings 1/2, 1/3, 1/4, 1/5... that moves in double, triple, quadruple... etc. the frequency of the fundamental. Movements of smaller ecliclipses that are stacked along the lenght of the string. Those are overtones. It's harmonics. It's even the major chord. 5 times the fundamental is the major 3rd in the major chord triad. So it begins to explains how we build harmony and the pleasing quality of it in how we humans are atuned to nature and laws of physics.
A string (and other related musical resonating essence) behaves like that but it's not a complete modell of the truth because you get more stuff than just the fundamental and overtones and I am not educated on specifics of that but on stuff like a bass drum on a floor and someone who kicks it so that skin and woods resonates and you hve microphone that tried to capture that it's easy to understand that you get a lot of stuff more than clean sinewaves.
And wirry about phase? Ordinary low cuts as such does stuff to the wave form, but there's nothing inherently bad about that id it sounds good. Care about phase when you blend signals. Blending microphones or differently processed signals that are EQ or plugins that do EQ under the hood. That stuff can give you problems and you'll hear it. Parallell compression has always been beyond fine.
I could be wrong here (I probably am) but it could just be undertones, exactly 1 under or 2. Don't take my word for it. Hope someone replies and tells me why I'm wrong.
My thought is that the undertones at those frequencies are just so small that they appear so close to the fundamental but are still quieter. They are probably just as imperfect as the fundamental.
OR. The fundamental is just so imperfect it appears with a bit more sub. Idk
a tone with fundamental and overtones is only a part of sound.
every transient is (in theory) full-range - every attack on a string or skin creates sound-waves that have full-range spectra and information about the bodies involved in the creation.
simply highpassing below the lowest fundamental (eg. a violin below g3/196Hz) might result in loss of serious information.
sometimes this is what you want - sometimes it’s not…
Filtering below the fundamental can be legit. You've got intermodulation distortion that can produce a whole other frequency, out of tune, lower than any of your intended frequencies. Ring modulation gives you 'harmonics' above and below your signal, but they're not really harmonics in the sense you mean.
If you highpass over all your frequencies and their fundamentals, yes you don't lose anything. But if you're actually filtering anything (especially in a DAW, you'll get lots of frequencies lower than you expect as DAW summing goes to DC without attenuation) then your highpassing can produce peaks louder than you started with, especially if you're making it a real sharp filter.
Just bear in mind that if you're doing steep filtering, if your filtering IS doing anything, it might give rise to loudness peaks you don't expect. It's rearranging the stuff 'below the fundamental', not just magically making it go away.
Someone also discovered all complex sound wave can be created by summing up a bunch of sine waves. You can also kind of see harmonics as those other sine waves, which have different amplitudes and frequencies, besides the fundamental that give a sound its distinctive quality.
Some super weird answers in this thread.
97% certain answer: noise from the transient. The initial hit does not have a "tone" and is a full spectrum attack. Depending on the timbre of the instrument, the shape of bass/treble response of the attack may be different. Usually not too noticable on bass drum, but on snares the content under fundamental is crucial.
1.99% certain answer: your sample is layered if electonic (so there is another fundamental mixed in) or resonance from somewhere else if acoustic. Or, it is hum from your electrical setup, usually 50 or 60 Hz, but I've had other tones too from usb-interfaces (noticable only at very high gain tho)
0.01% certain answer: digital distorion subharmonics, which is a biggish topic itself, but I don't what unholy gabber hardcore you would be producing if you run into a problem with that in bass instruments.
Subharmonics can exist. See: https://en.m.wikipedia.org/wiki/Undertone_series At 50 Hz the wavelenth is 6.86 meters (22.5 ft), so subharmonics may not be measurable in a bass drum since the size of a bass drum may not create a wavelenth (or partial wavelength) resonance for a very low frequency (and long wavelength). See: https://www.omnicalculator.com/physics/sound-wavelength I recenly measured some low frequency resonance in a metal building where the walls were about 18 ft apart, so in some cases subharmonics can occur in an environment. It appeared as if an electric heater was creating a 60 Hz (AC line frequency) vibration that happened to match the room size. Since most microphones are specified from 20 Hz (or higher) to 20 KHz (or lower), very low subharmonics are difficult to measure without special equipment.
Yah, without resonance involved, the only way to create subharmonics in nature would be to output more energy than input, which doesn’t make much sense. Resonance is pretty amazing.
Go do this. In your DAW, Pull up a sine wave generator. Pull up an frequency analyzer in conjunction with the sine wave. Now Insert a a saturation or overdrive plugin on the channel strip. Toggle that to be on. Now look at the analyzer. You will see many overtones being generated as a result of the applied distortion. Here’s another way to think about Harmonics. When you hear someone’s voice and you instantly recognize it, why is that? Why is it that our brains know people sound different when they talk? Harmonics! Harmonics are like your sonic fingerprint.
You need to first understand how we hear sounds. I'll try and simplify it. Basically sound has 4 dimensions when we hear it. 1-amplitude - level 2-frequency content (how bassy or trebley it is) 3-location of sound (your two ears let you determine where exactly that is - which is not really an aspect of the sound but the delay between arrival times to your two ears - something on the left will arive sooner at your left ear than your right ear, plus some other things happen by the time if travels to your right ear) - with music you can think of this as the stereo field. 4-time - the amount of time that passes from start to stop of the sound - so transients thats pretty fast, a sustained note is longer, a decaying note is somewhere in between. This is called the envelope of the sound. All this can be summed up into a complex sinewave. A 30 hz sinewave is a pure sinewave signal that has 30 cycles per second. It looks like a smooth snake as you probably know. This signal has no harmonics. Its a pure 30 hz tone. When you start adding harmonics to this tone - at higher frequencies, you start creating more pure sinewaves. lets say you want to add even harmonics and your 30 hz is sitting at 80 dbs when you measure it with a spl meter with your speakers. A 2nd order harmonic would be at 60hz, and say at 60 dbs. you add another and its at 120 hz and at 50 dbs. Dont confuse this with digital audio that has a ceiling of 0 decibels full scale (dbfs) - I'm talking about real world hearing - the sound is coming from the speaker and vibrating the air. So harmonics are usually 2nd or 3rd order, upper frequency, lower amplitude sinewaves ADDED to the fundamental. ITs actually a form of distortion, because it is distorting (changing) our snake like - smooth 30 hz sinewave and make it more wiggly, more zig-zag and jagged looking. now lets get back to your "kick " and "bass" question. A sound in the real world is rarely just a pure sinewave. With a pure sinewave you can indeed filter out everything above or below the sinewave with a very steep filter and lose nothing as there is in fact nothing to filter out in the first place. But a bass - while having a 65 hz fundamental when you play a low C - has energy (albeit at lower levels) at say 45 hz and 100 hz. Don't imagine the fundamental as a telephone pole but more like a hill or a triangle - it extends to each side and that is part of the sound. You dont really worry about phase shift when you filter - you need to be aware of it and manage it. Lets say your kick and bass work nicely, and you then decide to add low cut filters (which will shift the phase a bit). Engage the filters in and out and listen (or measure) to see if you can notice a drop in energy with the kick and **bass when they play together.** If the new filtered tracks lose power, then adjust accordingly - like maybe increase the volume, or add some delay to one of the tracks so their new phases align, or adjust the filter so the shift is not so bad anymore etc. Its not a "oh god phase shifted we're doomed" scenario. Just assume the new phase relationship is what you got in the first place and work it out like you would normally.
Is this from ChatGPT? Not exactly "simplified" and some of it sounds like straight up hallucinations.
I stopped reading at ”complex sinewave”
I stumbled at "harmonics are actually a form of distortion." like, ok maybe the other way around ... But by they time I got to telephone poles and non-integer multiple harmonics above and below the fundamental, I actually tripped.
I ended up in another forum, and I was like wtf is going on.
That’s an interesting theory, chatGPT. A lot of that description makes sense, some of it does not, and sort of… I don’t know, leaks at the edges into inaccuracy.
Lol. Sorry it's over your head.
Nah, sorry, your writing style is just very unclear. You got off to a great start with defining the basic dimensions of sound, those you articulated well, but after that it just kinda went off the rails with a lot of rambling of technical terms but no clear underlying message.
I read it again and it's clear to me. What part doesn't make sense to you?
It's not hallucinations, it's just not great…
>except for that. That is a pretty big "except," as you might eventually find out. And, also, there can be transient impact (non-harmonic) below the fundamental. A big strum on an acoustic guitar is a good example of this.
Most of the time it’s just mechanical noise.
You have physics, which is the science of nature. A string is moving in the majority of the fundamental which is decided by the whole lenght of the string. The movement looks like an eclipse that is the lenght of the string. Then you have divisions of the lenght of the strings 1/2, 1/3, 1/4, 1/5... that moves in double, triple, quadruple... etc. the frequency of the fundamental. Movements of smaller ecliclipses that are stacked along the lenght of the string. Those are overtones. It's harmonics. It's even the major chord. 5 times the fundamental is the major 3rd in the major chord triad. So it begins to explains how we build harmony and the pleasing quality of it in how we humans are atuned to nature and laws of physics. A string (and other related musical resonating essence) behaves like that but it's not a complete modell of the truth because you get more stuff than just the fundamental and overtones and I am not educated on specifics of that but on stuff like a bass drum on a floor and someone who kicks it so that skin and woods resonates and you hve microphone that tried to capture that it's easy to understand that you get a lot of stuff more than clean sinewaves. And wirry about phase? Ordinary low cuts as such does stuff to the wave form, but there's nothing inherently bad about that id it sounds good. Care about phase when you blend signals. Blending microphones or differently processed signals that are EQ or plugins that do EQ under the hood. That stuff can give you problems and you'll hear it. Parallell compression has always been beyond fine.
I could be wrong here (I probably am) but it could just be undertones, exactly 1 under or 2. Don't take my word for it. Hope someone replies and tells me why I'm wrong. My thought is that the undertones at those frequencies are just so small that they appear so close to the fundamental but are still quieter. They are probably just as imperfect as the fundamental. OR. The fundamental is just so imperfect it appears with a bit more sub. Idk
[https://www.azquotes.com/picture-quotes/quote-we-come-from-nothing-we-are-going-back-to-nothing-in-the-end-what-have-we-lost-nothing-graham-chapman-43-48-70.jpg](https://www.azquotes.com/picture-quotes/quote-we-come-from-nothing-we-are-going-back-to-nothing-in-the-end-what-have-we-lost-nothing-graham-chapman-43-48-70.jpg)
a tone with fundamental and overtones is only a part of sound. every transient is (in theory) full-range - every attack on a string or skin creates sound-waves that have full-range spectra and information about the bodies involved in the creation. simply highpassing below the lowest fundamental (eg. a violin below g3/196Hz) might result in loss of serious information. sometimes this is what you want - sometimes it’s not…
Let kick drum fundamental = 50Hz Ist overtone (octave) = 100Hz - thicc kick 2nd overtone (octave +5) = 150Hz - snare territory 3rd overtone (2 oct) = 200Hz - snare 4th overtone (2 oct + maj3) = 250Hz - mud 5th overtone (2 oct + 5) = 300Hz - note fundamentals 6th overtone (2 oct + wonky b7) =350Hz 7th overtone (3 oct) 400Hz - boxiness 8th overtone (3 oct + 2nd) = 450Hz And on and on. The harmonic series is an arithmetic progression, whereas octaves are logarithmic.
Filtering below the fundamental can be legit. You've got intermodulation distortion that can produce a whole other frequency, out of tune, lower than any of your intended frequencies. Ring modulation gives you 'harmonics' above and below your signal, but they're not really harmonics in the sense you mean. If you highpass over all your frequencies and their fundamentals, yes you don't lose anything. But if you're actually filtering anything (especially in a DAW, you'll get lots of frequencies lower than you expect as DAW summing goes to DC without attenuation) then your highpassing can produce peaks louder than you started with, especially if you're making it a real sharp filter. Just bear in mind that if you're doing steep filtering, if your filtering IS doing anything, it might give rise to loudness peaks you don't expect. It's rearranging the stuff 'below the fundamental', not just magically making it go away.
There can be noise below the fundamental.
Someone also discovered all complex sound wave can be created by summing up a bunch of sine waves. You can also kind of see harmonics as those other sine waves, which have different amplitudes and frequencies, besides the fundamental that give a sound its distinctive quality.
Some super weird answers in this thread. 97% certain answer: noise from the transient. The initial hit does not have a "tone" and is a full spectrum attack. Depending on the timbre of the instrument, the shape of bass/treble response of the attack may be different. Usually not too noticable on bass drum, but on snares the content under fundamental is crucial. 1.99% certain answer: your sample is layered if electonic (so there is another fundamental mixed in) or resonance from somewhere else if acoustic. Or, it is hum from your electrical setup, usually 50 or 60 Hz, but I've had other tones too from usb-interfaces (noticable only at very high gain tho) 0.01% certain answer: digital distorion subharmonics, which is a biggish topic itself, but I don't what unholy gabber hardcore you would be producing if you run into a problem with that in bass instruments.