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Cone displacement question

T

The Gaz

Sep 24, 2008
27
0
#1
After doing a lot of reading here and other places, I'm trying my hand at modeling some driver cab configurations in Bassbox Pro 6 and WinISD Pro.

I have a question about interpreting the cone displacement graphs and placing them in context of bass guitar. I'm wondering if the signal level I should be inputting is the rms power of my amp (200W in my case) or something else. I'm wondering because I read that the fundamental of a note only accounts for about 20% of it's total power, but I don't know if that's true and can't find any other info on the topic.

I attached an example. Would this mean this design would fart out around 100Hz with a 200W amp, or am I interpreting it incorrectly? I'm wondering if say, a low E, is actually putting out 200W 100Hz when my amp is set for max clean output power. Hope that makes sense.

In essence I'm really just trying to figure out how to practically interpret the cone displacement data, so any tips would be great!

Thanks!
 

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#2
It would fart out with a pure sine wave arounf 70..80Hz powered with 200 Watt. But it would not fart out with a spectrum that starts at 50Hz with the Fundamental and spreads also power to a wide range of Overtones.
The total then may be 200 Watt as well but the speaker would not fart.

If you want to know the exact excursion for a bass guitar signal needs to analyse the spectrum of the signal and then evaluate excursion for each particular frequency of the whole spectrum.

However the main problem is the random appearance of transients. Transients appear just the moment of a stroke to the string. Even touching a string with the fingers will cause transients, or some damping tecniques as well.

EQ settings influence excursion because a decent bass boost shifts the majority of power to the low end.

There are a very lot of varibales that influence excursion althogh the pure number of watts remains at a similar number. It's hard to predict an excursion unless all of these parameters are unknown.
Not to forget that string B0 will cause more stress to the speaker then string E1.

Different cab tunings influence the power handling as well. A tuning of 50Hz is more robust to random transients then a tuning of 60Hz bcause excursion then will noticable increase.
 
#3
The Gaz said:
After doing a lot of reading here and other places, I'm trying my hand at modeling some driver cab configurations in Bassbox Pro 6 and WinISD Pro.

I have a question about interpreting the cone displacement graphs and placing them in context of bass guitar. I'm wondering if the signal level I should be inputting is the rms power of my amp (200W in my case) or something else. I'm wondering because I read that the fundamental of a note only accounts for about 20% of it's total power, but I don't know if that's true and can't find any other info on the topic.
Click to expand...

Have a look at Invalid Link Removed. In particular, figure 3 and the accompanying text.
 
#5
bump

It makes me wonder this thread has not any more hits and posts but the subject relates to cone displacement?
It makes me wonder because cone displacement is one of most popular subjects discussed on talk bass?
 
Last edited:
#6
My speaker design program includes an estimate of cone excursion when the speaker is fed with an equal mixture of 4 harmonics. It is the "waveform based" curve in the graphs.

Invalid Link Removed

The program is experimental, could contain bugs, yadda yadda. Also, if your amp has a "scooped" voicing, which is not uncommon, then your signal may already be pretty heavy on the fundamental.
 

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