Voices (and not the kind in your head)

[misskitty]

So my physics class is studying sounds and light waves right now. We were discussing how different things affect the sound waves. My question relating to biology is this: my mother and sister and I sound very much alike...except that they tell me my voice sounds as though it is a lower pitch than theirs. Why is this?

 

[KingNothing]

Maybe because it is a lower pitch? I don't see what the question is - two voices can sound alike and have overall lower frequencies (pitches).

 

[Moonbear]

Do you mean how your voices sound to someone else? Or how they sound to yourself? When you hear yourself speaking, you're not only hearing the sounds as they are transmitted through the air, but also as the vibrations are transmitted through your own body (your ear is detecting sound via vibrations), so you will sound differently to yourself when you are speaking than you will if you record your voice and listen to yourself on a recording.

If you are asking why different people sound different, it is related to the length and thickness of the vocal chords, which is variable.

 

[cronxeh]

Would the shape of your tongue and flexibility of its muscles also affect it? If you make sounds with your tongue, I guess it would make sense, right Moonbear?

 

[Huckleberry]

I think it has to do with the pitch and frequency of your voices.
Interval Frequency Ratio Examples
Octave 2:1 512 Hz and 256 Hz
Third 5:4 320 Hz and 256 Hz
Fourth 4:3 342 Hz and 256 Hz
Fifth 3:2 384 Hz and 256 Hz
Your voices can have a different pitch but still have a resonance with the sound of your family members.

http://www.glenbrook.k12.il.us/gbssci/phys/Class/sound/u11l2a.html

Huck

 

[Moonbear]

Would the shape of your tongue and flexibility of its muscles also affect it? If you make sounds with your tongue, I guess it would make sense, right Moonbear?

Okay, makes sense to me. Of course the sounds we make also require that we force air past those vocal chords, so yeah, breath control would affect the sounds, and since some people can sing on key, we have voluntary control of the pitch. Though, I don't think we can control the timbre as much. I'm not really sure what the physics are of timbre vs pitch...sort of the way you can play a middle C on a bunch of different instruments, so the pitch is the same, but you still know the sound of a trumpet from that of a piano, so there are other aspects to sound quality other than just frequency (pitch is frequency, isn't it?). Is timbre amplitude? Or noise (no pun intended)? Or what? I'll welcome the input of physicists on this question, since I really can't be of any help beyond length and thickness of vocal chords.

 

[Hurkyl]

Timbre is the relative strength of the harmonics.

When you play a middle A (440 Hz) on any instrument, it is also producing harmonics -- sounds that occur at integer multiples of the fundamental frequency. So, the instrument is also making sounds at a pitch of 880 Hz, 1320 Hz, 1760 Hz, et cetera. Your ear naturally blends them together into a single sound, and their relative strengths yield the timbre of the sound.

 

[KingNothing]

Hurkyl, I knew what harmonics were and what they had to do with timbre, however I've never known why harmonics happen, and why some instruments produce different harmonics. Why?

 

[Ouabache]

I knew what harmonics were and what they had to do with timbre, however I've never known why harmonics happen, and why some instruments produce different harmonics. Why?

Depending on the shape and density of the material, more than one frequency have natural resonances within an instrument. Not only the fundamental, but each of the harmonics will resonate with varying amplitudes.
The vocal chord and the associated cavity with shaping mechanisms such as the tongue and cheeks, also comprise an acoustic resonant system. The nearest musical instrument analogous to our voice may be a clarinet or bagpipe (they each use a vibrating reed adjacent to a resonant cavity).

Here is a great illustration. Find a piano, open or lift the cover to the strings, depress the pedal that creates a sustain and sing a pitch towards the strings. You should hear, not only the fundamental string vibrating, but also a composite of harmonic resonances (additional vibrating strings) of attenuated amplitude.

 

[hypnagogue]

Timbre is the relative strength of the harmonics.

That's one aspect that goes into determining timbre, but it's not the only one. This site (first Google return on "timbre," FWIW) defines it as follows:

Sounds may be generally characterized by pitch, loudness, and quality. Sound "quality" or "timbre" describes those characteristics of sound which allow the ear to distinguish sounds which have the same pitch and loudness. Timbre is then a general term for the distinguishable characteristics of a tone. Timbre is mainly determined by the harmonic content of a sound and the dynamic characteristics of the sound such as vibrato and the attack-decay envelope of the sound.

The Wikipedia entry on timbre also suggests that psychoacoustics (how the brain processes auditory information once it's reached the ear) is an important component: "The physical characteristics of sound which are used in the determination of timbre are spectrum and envelope, but psychoacoustics also plays an important and little-understood part."

One piece of evidence that might demonstrate the importance of psychoacoustics in determining timbre is the following tidbit, from the previous page: "Some investigators report that it takes a duration of about 60 ms to recognize the timbre of a tone, and that any tone shorter than about 4 ms is perceived as an atonal click."

 

[Hurkyl]

Ah, that's good to know. I guess I was just talking about the spectrum then -- I didn't realize the envelope was a component of timbre.

 

[misskitty]

Do you mean how your voices sound to someone else? Or how they sound to yourself? When you hear yourself speaking, you're not only hearing the sounds as they are transmitted through the air, but also as the vibrations are transmitted through your own body (your ear is detecting sound via vibrations), so you will sound differently to yourself when you are speaking than you will if you record your voice and listen to yourself on a recording.

If you are asking why different people sound different, it is related to the length and thickness of the vocal chords, which is variable.

I meant how they sound compared to someone else. I new about how they sound to me.

 

[misskitty]

I think it has to do with the pitch and frequency of your voices.
Interval Frequency Ratio Examples
Octave 2:1 512 Hz and 256 Hz
Third 5:4 320 Hz and 256 Hz
Fourth 4:3 342 Hz and 256 Hz
Fifth 3:2 384 Hz and 256 Hz
Your voices can have a different pitch but still have a resonance with the sound of your family members.

http://www.glenbrook.k12.il.us/gbssci/phys/Class/sound/u11l2a.html

Huck

Ok that would make sense. Could it also be how different people interpret the sound of our voices? Is it possible to have the same frequency and voice pitch with someone else? Does it happen in families?

 

[Huckleberry]

The pitch of a voice is made of many different frequencies combined. These frequencies all interact with each other to create a rich sound. Voices are very distinct from one person to another but I imagine there are voices that are so similar as to be indistinguishable to the human ear. As family members often share physical traits, it is possible that the similarities in your vocal chords, lungs, throat, mouth, tongue, teeth etc. could produce a similar pitch. I find it unlikely that your voice is indistinguishable from your family members unless you are identical twins. More likely is that your accent, slang, and manner of speech are learned traits that you have in common with your relatives.

People tend to hear what they are trained to hear. For example, if you heard a Japanese person speaking English you could probably tell that they were Japanese. The l and the r sounds are difficult for them to distinguish because they are similar in the Japanese language. So when they speak in English these sounds get confused, but the Japanese person doesn't hear it like you do. The same can be said for any language.

 

[Ouabache]

Is it possible to have the same frequency and voice pitch with someone else? Does it happen in families?

Yes, all the female voices in my family sound very similar and often hard to tell apart over the telephone. Same is true for many of the male voices in my family. We have inherited genes that have coded for very similar configurations of our vocal chords and associated resonant cavities.

People tend to hear what they are trained to hear. For example, if you heard a Japanese person speaking English you could probably tell that they were Japanese. The l and the r sounds are difficult for them to distinguish because they are similar in the Japanese language. So when they speak in English these sounds get confused, but the Japanese person doesn't hear it like you do. The same can be said for any language.

Interesting that you mention Japanese, I recall an interview on U.S. National Public Radio with a woman researching pitch and memory. We commonly recall memories of concepts and images, but how many can recall a specific audio pitch? Several members of my family can. We've inherited perfect pitch which comes in handy because most of us are also musicians.

Back to the interview of the woman on NPR... She wanted to find out if those people who speak tonal languages also recall specific pitch. Many Southeast Asian and African languages are tonal, including Chinese, Japanese, Vietnamese.. (by tonal, the meaning of a word is conveyed not only by consonants and vowels, but also by the pitch it is spoken. Linguistics is not my forte, so a better description of tonality in language may be viewed at --->http://www.mnsu.edu/emuseum/cultural/language/tonal.html

Perhaps some PhysicsForum members who speak tonal languages can help me out here

This researcher found they indeed recall specific pitch, just like those of us who exhibit perfect pitch. Perhaps this ability to remember pitch is more common than previously supposed. As in all languages, tonal languages are learned by children. Their brains are in a mode for language acquisition. Perhaps more of us who learn non-tonal languages could develop memory for pitch, if it is reinforced at a young age.

 

[misskitty]

Ouabache, that is really interesting. The females in my family all sound riduclously alike. Its kind of funny when I answer the telephone and a family friend mistakes me for my mother and asks if my husband is home.

 

[DeepThunker]

Go to this site
http://www.falstad.com/fourier/
When here play with the java.

When a piano is played, say 440 hertz, the strings around it, as well as the wood box, resonate. That is to say vibrate. The other string's notes will never be as loud as the 440 hertz note you played. This makes sense as you have energy transfer loss. Because the notes are resonating the other notes are in phase with the Original note.
The waves blend together and create a Fourier note. Since instruments of the same type are made precise, this note becomes that instruments sound. Trumpets always sound like trumpets. Ones made of silver sound different than the normal brass ones. This is because the materials resonate differently.
To answer your question: Your family shares genes for how you are structured. Vocal chord size and tightness can change the timbre. Also I sense you are a singer. When you singer it is important to have open space in back by raising the soft pallate. Similar to biting into an apple or yawning. What happens when you do this? Sound bounces of more things(resonates more in the process) and comes out rich and opera like. When you sing eeeeeeeeee really annoying-like, you switch the amount of resonance and sing a peircng note.

 

[Ouabache]

When a piano is played, say 440 hertz, the strings around it, as well as the wood box, resonate. That is to say vibrate. The other string's notes will never be as loud as the 440 hertz note you played. This makes sense as you have energy transfer loss. Because the notes are resonating the other notes are in phase with the Original note.
The waves blend together and create a Fourier note.

I am familiar with Jean Baptiste Joseph Fourier. He pioneered what is known today as Fourier Analysis, while experimenting with the propagation of heat, along the shores of the Nile, while serving in army of Napoleon.

I've never heard it called a Fourier note. I must amend my earlier post, where I said only harmonics are generated. The other frequencies are overtones of the fundamental 440Hz. Overtones are made up of harmonics, which are integral multiples of the fundamental, plus non_integral multiples or inharmonic overtones.They are (as you mentioned) lower in amplitude. If you were to input those frequencies to a spectrum analyzer (which plots freq versus amplitude), you would see a nice graph of that relationship.

I have heard that our brain may believe it is hearing the fundamental, when only overtones are present. I haven't personally tried this but do know other musicians who have confirmed this.

 

[Evo]

Ok that would make sense. Could it also be how different people interpret the sound of our voices? Is it possible to have the same frequency and voice pitch with someone else? Does it happen in families?

My younger sister and I sound identical. Even my mother can't tell us apart. The first time I noticed it was when my sister left a message on my answering machine and I was confused at first, because I thought it was me. She sounds just like my recorded voice sounds to me.