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Bass Guitar Frequency Reproduction
Posted: Wed May 12, 2010 11:19 pm
by jbass
Let's say you have a bass rig with a speaker that's rated down to 60 Hz. How is possible to get solid reproduction of the 31 Hz B string from such a cabinet? I know this has something to do with the second harmonic of the lowest notes, but I'm not clear on how all this works. Is this effect only in play until the fundamental of a note is at or above the roll-off frequency of the driver? I'm just trying to broaden my understanding.
Re: Bass Guitar Frequency Reproduction
Posted: Wed May 12, 2010 11:30 pm
by wallywally
Here is my limited $.02. The second harmonic is normally the strongest sound from a bass guitar. The longer the scale the stronger the root note. Example: a low B on a piano will have a lot more 31hz content than a low b on a 5 string bass.
Re: Bass Guitar Frequency Reproduction
Posted: Wed May 12, 2010 11:51 pm
by jbass
OK, that makes sense. So we are actually hearing the fundamental to some extent, but the harmonic structure of the bass is such that the second harmonic is stronger than the first. Does that sound right?
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 3:53 am
by WB
jbass wrote:So we are actually hearing the fundamental to some extent, but the harmonic structure of the bass is such that the second harmonic is stronger than the first. Does that sound right?
From what I've seen, the fundamental and first harmonics on my electric bass are about equal in output, but the fundamental decays quicker than the first harmonic. I think that's pretty much typical.
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 7:04 am
by Bill Fitzmaurice
WB wrote:jbass wrote:So we are actually hearing the fundamental to some extent, but the harmonic structure of the bass is such that the second harmonic is stronger than the first. Does that sound right?
From what I've seen, the fundamental and first harmonics on my electric bass are about equal in output, but the fundamental decays quicker than the first harmonic. I think that's pretty much typical.
The lower you go the less fundamental there is. With a low B there's not much at all with electric bass cabs. It's a matter of the tone being defined by the speaker more than the source.
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 8:33 pm
by jbass
Bill Fitzmaurice wrote:The lower you go the less fundamental there is. With a low B there's not much at all with electric bass cabs. It's a matter of the tone being defined by the speaker more than the source.
Is this because the lower frequencies are reproduced with increasingly less volume due to the downward slope of the response curve below the roll-off point?
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 9:14 pm
by Bill Fitzmaurice
jbass wrote:Bill Fitzmaurice wrote:The lower you go the less fundamental there is. With a low B there's not much at all with electric bass cabs. It's a matter of the tone being defined by the speaker more than the source.[/quote
Is this because the lower frequencies are reproduced with increasingly less volume due to the downward slope of the response curve below the roll-off point?
It's because your bass doesn't have a 96 inch scale, and speakers capable of running flat much below 60Hz at high output are rare.
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 9:29 pm
by tdogg
some bass players are working towards producing more fundamental (35" scale basses or longer, 21" woofers, bi-amping, etc) but that doesnt change the way our ears work. IMO in most live music you really dont need the lower fundamentals. in rock music it usually ends up sounding like poop.
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 10:46 pm
by jbass
Bill Fitzmaurice wrote:It's because your bass doesn't have a 96 inch scale, and speakers capable of running flat much below 60Hz at high output are rare.
OK, so this boils down to mechanical physics. Now I understand this a lot better. Thanks.
Re: Bass Guitar Frequency Reproduction
Posted: Thu May 13, 2010 11:10 pm
by jbass
tdogg wrote:some bass players are working towards producing more fundamental (35" scale basses or longer, 21" woofers, bi-amping, etc)...
I've read about electrics with scales up to 38", but I would imagine it would be pretty difficult to reach the first few positions if the bass is being played horizontally unless you had long arms and long fingers. Maybe not. I've also read about a few companies that are producing basses with low F# and low C# strings. I wonder if you can even distinguish between the notes when they're that low!
Re: Bass Guitar Frequency Reproduction
Posted: Fri May 14, 2010 7:21 am
by Bill Fitzmaurice
jbass wrote:I've also read about a few companies that are producing basses with low F# and low C# strings. I wonder if you can even distinguish between the notes when they're that low!
You can't distinguish pitch much below 50Hz. Pitch, tone, definition, it's all in the harmonics. If it was not so you would not be able to tell a bass from a bassoon, or a piccolo from a violin.
Re: Bass Guitar Frequency Reproduction
Posted: Fri May 14, 2010 7:46 am
by tdogg
jbass wrote: Maybe not. I've also read about a few companies that are producing basses with low F# and low C# strings. I wonder if you can even distinguish between the notes when they're that low!
you can, but your hearing the first harmonic of that note, which is the same as the fundamental of the F# and C# on a "regular" bass. so it works out. at least thats how i understand it, please correct me if im mistaken
Re: Bass Guitar Frequency Reproduction
Posted: Fri May 14, 2010 12:52 pm
by loupey
These are 'wavelet transforms' of 2 bass guitar tracks (solo). The horizontal line is TIME, the vertical FREQ, and the colors, INTENSITY. red being the strongest, blue the weakest, and yellow the middle. A full screenprint would have lost too much resolution.
The graph is limited to 10Hz - 1KHz. The lowest 'red' is the low B string (31Hz).
Clip1a = 5 string studio track that sounds deep, mellow, barely any highs or mids. You can see the 3 harmonics (1st harmonic = fundamental tone).
Clip2a = my 5 string bass, flat EQ, direct. 9 harmonics visible.
I don't know for certain if the Clip1a is direct or from a speaker. I know Clip2a is direct, no speaker.
I think that is correct, tdogg. * I mean an F# is ~23Hz...but I'd say you'd be hearing the 3rd harmonic (2nd overtone) @ ~69Hz, but feeling the 2nd harmonic @ 46Hz.*
*EDIT: F# = 23hz, not 16hz.
http://en.wikipedia.org/wiki/Harmonic