Sounds, frequencies, SPL reference

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jqp

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Sounds, frequencies, SPL reference
« on: 1 Oct 2003, 06:12 pm »
When considering speakers and their specifications you need to understand the basics of the music you will want your speakers to reproduce.

Frequency of a sound is measured in Hertz, or cycles/second.
SPL = Sound Pressure Level, measured in decibels(dB).  A 3dB gain is a doubling of the loudness of the sound.

The table below is cobbled together from several sources...

                                                                                                                                   
InstrumentFrequency range HzSPL Range dB
Pipe Organ BIG16.00 - 2,093.0035 - 110
Piano (concert)27.50 - 4,186.0060 - 100
Bass Tuba43.65 - 349.23
Double Bass41.20 - 246.94
Timpani 165.40 - 110.0035 - 115
Cello65.41 - 987.77
Trombone82.41 - 493.88
Guitar82.41 - 880.00
Voice(Bass)87.31 - 349.23
Voice(Baritone)98.00 - 392.00
French horn110.00 - 880.00
Viola130.81 -1,174.00
Voice(Tenor)130.00 - 493.88
Voice(Cntralt)130.81 - 698.46
Violin196.00 - 3,136.0042 - 95
Clarinet164.81 - 1,567.00
Trumpet164.81 - 987.7755 - 95
Flute261.63 - 3,349.30
Voice(Soprano)246.94 - 1,174.70
Cymbals?40 - 110


These frequency ranges are the "natural" frequencies and do not include harmonics (higher and lower over- and under-tones which are said to make music sound like "music")

The Bass range is generally below 400Hz
Mid-bass is 80-400Hz
Sub-Bass is 20-80Hz

Midrange (Mids) falls in the 400Hz-2500Hz range.
This is where most musical tones and voices fall.

Treble (Highs) is 2500Hz (2.5KHz) and up.

(These ranges are not cast in stone)

Human hearing is generally 20Hz-20,000Hz. Often there is hearing loss in certain ranges or above a certain high frequency, say 16,000 Hz. Guitarist Leo Kottke was diagnosed with "machine-gun trauma" in Germany - hearing loss in the 3000Hz range. Note that the guitar's natural range is about 80-900Hz so he is probably missing some of the higher harmonics only.

Sound Pressure Levels of 80 dB can damage your hearing over time. In fact, orchestra members can suffer hearing damage, so it is not just a problem with rock and roll.

You will probably listen at reasonable levels most of the time, with occaisional forays into the higher SPLs to wow your friends, or to see if the 1812 Overture really can blow your woofers (it can).

It costs more, often substantially more, to get as good SPL levels in the lower bass range as in the mids and highs. So many speakers begin to "roll off" below the mid-bass range (80Hz). You may be able to live with this. If not, you will want subwoofers, or you will want a more capable speaker that can really get down low with some authority.  Of course, both options cost more.

warnerwh

Sounds, frequencies, SPL reference
« Reply #1 on: 2 Oct 2003, 05:26 am »
Thanks for the breakdown of instruments and their frequencies. Where do cymbals fall?

Captain Humble

Sounds, frequencies, SPL reference
« Reply #2 on: 2 Oct 2003, 06:23 am »
jqp,
Great post!
Thanks.

jqp

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Sounds, frequencies, SPL reference
« Reply #3 on: 2 Oct 2003, 03:40 pm »
Quote from: warnerwh
Thanks for the breakdown of instruments and their frequencies. Where do cymbals fall?


SPL of Cymbals is added - anyone know the frequencies?

MaxCast

Sounds, frequencies, SPL reference
« Reply #4 on: 2 Oct 2003, 04:37 pm »
To double the volume (spl) an amplifier must provide 10 times the power (watts).

Room gain can boost bass frequencies by 3dB.

As you move xx feet from your speaker the spl will drop by xx.
(need some help with this one)

Sean Parque

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Sounds, frequencies, SPL reference
« Reply #5 on: 3 Oct 2003, 11:57 pm »
Quote from: MaxCast
To double the volume (spl) an amplifier must provide 10 times the power (watts).

Room gain can boost bass frequencies by 3dB.

As you move xx feet from your speaker the spl will drop by xx.
(need some help with this one)


As you move 1M or 3.275' from your speaker, the spl will drop by 6dB.

Sean

azryan

Sounds, frequencies, SPL reference
« Reply #6 on: 1 Nov 2003, 05:42 pm »
"-As you move 1M or 3.275' from your speaker, the spl will drop by 6dB."

That's a point source speaker. A line source speaker is only 3db.

And isn't that 'at double the distance' for either one not 'per meter' like seems to be implied here my Max and Sean?

Meaning -if you're 2 meters away from a point source and it's 86db there, then it'll be 80db at 4 meters away, not at 3 meters. Right?

"-Sound Pressure Levels of 80 dB can damage your hearing over time."

Really?? I think that SPL level is low. Where did you get that from? We'd all have hearing damage from all our speakers if that was true. And it'd be pointless for any of us to have amps that put out more than 1 Watt is we valued our hearing.

"-In fact, orchestra members can suffer hearing damage, so it is not just a problem with rock and roll."

True, but both get MUCH louder than 80db and why that hearing damage prob. comes up.

Great chart of the fundamentals, but this line?....

"-These frequency ranges are the "natural" frequencies and do not include harmonics (higher and lower over- and under-tones which are said to make music sound like "music")-"

It makes it sound like it's a 'rumor' that harmonics matter.

Harmonics ARE greatly important. 100% as important as the fundamental -which then greatly effects this freq. chart.
Cymbals can go out to 100,000Hz (not that we can hear that or would want to -I still don't understand why some speakers try to recreate these inaudible ranges when the only thing it can do is damage the audible range we actuall NEED them to play).

Harmonics are what makes any two instuments playing the same fundamental tone sound like two diff. instuments.
This issue of Harmonics is what makes charts like these so tough to learn anything from -though this chart IS totally accurate.

Take a Violin....

196Hz to 3,136Hz.... ok, but it's the harmonics that make a Violin sound like a Violin and not a Piano or a Clarient playing the Exact same notes.

(As stated already) Harmonics are multiples of the main frequency above and below, so w/ almost ANY instrument multiply and divide these fundamentals a few times and you'll see we're talking about a LARGE audible range when you include a few orders of Harmonics.

I heard (I'm not sure though) that harmonics of some instruments can sometimes be louder than the fundamental tone even.
Talking about instruments and freq., but ignoring Harmonics is pretty pointless.

Take a look at the vocal ranges...
Pretty much all of them are under about 1,000Hz on the chart (again.. that's accurate for the fundamental)...

A newbie might look at this chart, and think then that the tweeter in whatever speaker they own is 'not doing anything' when a voice is singing (or 'hardly doing much', or something like that).

My current speakers are 2-ways and cross at about 1,200Hz. I can unplug the woofer section and still totally hear any vocals in any song. They're clear and detailed...there's just no weight to any of them.

Plugging in the woofer section and unplugging the treble section, I can still hear the vocals, but this time there's no detail to any of them. Like they're all muffled and lifeless.

Hard to put a 'percent' on what I hear from both sections... but it sounds about 50/50 to me from woofer and planar treble sections even though technically... the 'fundamental tones' of voices are mostly always coming from the woofers only.

I've never seen a chart that added harmonics onto the list and showed how strongly they effect the actual instrument that's named on the chart.
If anyone can find one like that... I think that'd be great.


As for what's Bass, Mids, and Treble... there seems to be two 'camps'....

The 'typical speaker driver camp', and the 'audible octave/musical instrument camp'...

jpq pretty much listed the speaker driver version going by the idea of where a typical dome tweeter crosses over (~2500Hz), and how low a typical midrange cone usually runs down to be crossed w/ a bass cone (~250Hz-500Hz).

The other 'camp' divides up the three ranges in fairly balanced full octaves and ignores what typical speaker drivers can or can't do.

(found here at S'Phile...   http://www.stereophile.com/fullarchives.cgi?50    along w/ lots of other good info.)
 
Bass ~20-160Hz (3 octaves).
Midrange ~160-1300Hz (3 octaves)
Treble ~1300-20,000Hz (4 octaves)

jqp

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Sounds, frequencies, SPL reference
« Reply #7 on: 1 Nov 2003, 06:03 pm »
"I've never seen a chart that added harmonics onto the list and showed how strongly they effect the actual instrument that's named on the chart. "

It would be a shame if you did not come up with this as you did a nice job of presenting why harmonics in many ways "are" the music!

Good post on a very important point. I do disagree with one thing. I have 2 different steel string flat-top acoustic guitars, with the same brand and guage strings on them, same number of frets. They sound very different to me, although to many they both sound like "guitars". In addition to harmonics, there is tone, timbre, wave shape etc. - that comes from the body of the instrument - that make instruments sound so different.

azryan

Sounds, frequencies, SPL reference
« Reply #8 on: 2 Nov 2003, 08:21 pm »
"-It would be a shame if you did not come up with this as you did a nice job of presenting why harmonics in many ways "are" the music!"

Well, the problem is that to make this chart you'd have to record all these instruments and put the info on a computer that shows you what was recorded which includes all the harmonics and their strength and graph it out. I'm not in a position to be able to do that.
 
I figure SOMEONE musta done this though and shoved it online... but I couldn't find one in recent searches.

I know I've seen a chart once that had a band for the fundamentals of diff. instuments (the notes they play) and then extended the band to how far out the harmonics typically go. That's close to what I'd want to see posted here and shows just how FAR beyond the fundamentals most instruments play.

"-I do disagree with one thing.-"

What exactly do you disagree with? Are you saying I said all guitars sound alike? Let me make it clear... they don't.
And the harmonics are the main reason for why two guitars or any two DIFFERENT instuments sound diff.

It's also the reason why some instuments can sound about the same playing the same notes like maybe a Violin or a Viola or Cello playing the same note. Damn hard to say which it is at times, but if you can then it's harmonics that are making the diff.

If your two guitars sound diff. (and I believe you that they do), the guitar bodies are effecting the resonances of the sound after you pick the same note on each. Perfectly normal. That's what guitar bodies do.

Play the same note w/ the same type of strings on a Fender strat and Les Paul UNAMPED where the solid bodies don't do hardly anything and the two will sound about the same. Basically no harmonics beyond the string's own harmonics which being the same string and note... will be the same.

"-They sound very different to me, although to many they both sound like "guitars".

Well, I'm sure they both sound like guitars to you too right??? They ARE guitars so they pretty much HAVE to by definition. hehe

You're just better able to tell the however subtle diff. between 'em compared to other people. Like how many of us can tell things about speakers and our sig. others or friends can't hear any damn diff.

"-In addition to harmonics, there is tone, timbre, wave shape etc. - that comes from the body of the instrument - that make instruments sound so different."

You should look up what those words mean. Timbre and tone are the pretty much same thing. Both are bacially harmonics in musical instruments.
In speakers they basically both mean the freq. response. Rolled off highs will be 'tonally' dull. Very flat speaker is 'tonally' very accurate.

Timbre is this diff. between two instruments or speakers (now you don't have to look it up. heh).

Wave shape... you'll have to say what you mean that.

 "-These frequency ranges are the "natural" frequencies-"

'Natural freq."? That's not really an accurate term.

If you want to use that term then it'd HAVE to mean fundamental freq. (which is what you should have written) PLUS the harmonics because that's what acutally comes out of these instruments 'naturally'.

And I don't get your point about the body of the instument effecting sound? Of course it effects sound. That was MY point I was trying to make to you, but you talk about how you disagree with me? I don't get 'how' you disagree or with 'what'?

On the chart you posted it's only made up of the fundamental freq. the instruments make (which are exact freq. and easily charted). That's only a part of the sound you hear and what 'sound' is from each of these instruments on the chart. Sometimes a small part, often a large part, sometimes larger than the original freq.

It depends on the instrument and the note being played.

Like how you can play the same note on an elec. keyboard, but change the sound to a bazillion diff. things. That's harmonics, and here there is NO physical piano or guitar, etc.. body, and the note and volume stay the same. And that's all sound is.

Without harmonics all instuments would sound the same and all sound like clean sine waves, which is pretty much impossible to do non-electronicly.

Maybe you think the guitar's body's effect on the sound is something diff. than harmonics? It's not. It's the thing the mainly CREATES those harmonics. You can't talk about a guitar's sound and skip such a HUGE element of it's sound.

What 'Sound' is not mystical or magical all these special elements. It's really pretty simple.
Fundamental, harmonics and amplitude. I'm 'pretty sure' that it.

Once you record the sound of a guitar or piano, etc... as a simple waveform... if you play that back on a stereo that is very accurate you'll be getting pretty much the same sound that came out the guitar or piano, etc... even though the speaker is not (hopefully) adding it's own cabinet sound or driver resonating (and why speaker design is in this way totally opposite of instrument making).

Part of my point was that if someone goes by this posted chart they're not even close to getting an accurate idea of the actual sound that comes out of the listed instruments, and what's recorded, and what's spit out their speakers.