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Double Bass Anyone analysed acoustics.....?

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Pbassred

Feb 21, 2004
755
7
65
Hatfield, Herts, UK
#1
I read the FAQs and searched so don't throw rocks ok?

Has anyone ever carried out a technical investigation into the sonic differences between a double bass and and electric Fretless (lets leave the frets out for now!). Obviously they sound different, but where does that come from?

Does the DB have a faster decay? More low Fequencies? Harmonics from the wood (which?), does it echo? Does the Electric have a more even (and less natual) frequency response?

Ok go! :hiding:
 
#2
I don't think you need a technical analysis. You could do scientific studies, but one's ear is far better, as far as the real world.

Acoustics do have all those qualities you mentioned. Some are dictated by the strings you use...then there is the construction of the bass, be it carved or laminate or hybrid...then there's age and so on, ad ifinitum.

I have played lots of EBs and also own an EUB as well as my UB. Funny how years ago, I always tried to get my Fenders to sound like UBs. There's no substitute when it come to moving all that air. I think that's what it really comes down to.

gomez
 
#8
No, really, strings vibrate in fractions, so as a whole, as a half, as thirds, as quarters, fifths etc.

A longer string makes a more audible upper frequency. That is the throaty mid range sound you hear, and higher ringing.

As the string vibrates, it stretches and contracts. That part is similar to electric bass, but on the upright the top moves, so the stretching and contracting is more evident. It almost sounds like Vibrato sometimes.

Those are two things I see immediately from scientific observation.

If you have a crt TV or monitor, you can watch the string under the constant strobe light of the screen and see these things for yourself.

Lower input into the string has a more even response, and sounds more even, pulling the string very hard makes the change in impact and decay more apparent.

I have no spectrum analysis, I prefer to think of all this as art meets quantum physics in action.. Good luck figuring out what you want to figure out.
 
#10
Pbassred said:
No you missunderstand the question. I know where the differences come from. I understand what the differences are in the construction and technique.
what I am asking is about differences in the audio spectrum and envelope.
Click to expand...

you already said that.
Alex told you the double bass had stronger harmonics and therefore more overtones. that means the double bass will have a larger "audio spectrum"...i don't know what you mean when you talk of the "envelope"...i use my ears to decide what sound i like rather than scientific instruments and studies...perhaps you should do a little googling if you're bored, fella.
 
#12
He wants to know how the waveforms differ. Like if he graphed the signal and analyzed it to characterized the difference in the signal. Eg. spectral content, phase relationships, attack, decay... (By enveloped I think he is refering to a plot that connects the tops of the peaks together and the bottoms of the valleys together.)

PBassRed - you might enjoy reading this:

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It probably also has a bunch of interesting references, if you're into that sort of stuff.


Cheers,

Jim
 
#13
I've just plotted a really simple magnitude response plot of the frequencies of the UB and EB in steady state. Obviously the harmonics move over time, but the spectral envelope is relatively constant in steady state and I've just taken a frame of audio from steady state.

The arco UB shows a richer set of mid to higher harmonics with various resonances (peaks in the envelope) and these contribute to the perceptual 'richness' of the UB sound - compared to the EB which generally has a smooth monotonically decreasing envelope (i.e. no resonant peaks besides the first one).

The frequency response of the plucked EB and the pizz EB are quite similar spectrally, but the EB has a bit more higher harmonics. The main perceptual differences will primarily be in the temporal changes - UB pizz has shorter sustain than EB.

Hope this helps...
 

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#15
Well frequency analysis is typically done with an FFT (Fast Fourier Transform). You take a signal's time waveform and the FFT allows you to analyse the frequencies that make up the signal (in terms of sine and cosine waves).

I just did it in Matlab (software made by mathworks)...
 

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