About Speaker LF Resonance

If you are running an IR direct to PA and a power amp/cab from output 2, would you match the LF Resonance to the IR or the physical cab for best results?
 
waxcalifornia said:
If you are running an IR direct to PA and a power amp/cab from output 2, would you match the LF Resonance to the IR or the physical cab for best results?
Click to expand...
That depends. What's more important to you: what the audience hears or what you hear?
 
Interesting read.

Looking at the default parameters for the Jazz120 model in Axe-FXII Quantum 10 I read resonance values of 2.5. Since the Roland Jazz Chorus features a rather straight forward solid state output stage, I would assume a very low output impedance --> very high damping factor

--> resonance of 0. --> ???

Edit: just realized, that there are Roland Jazz Chorus with and without mixed feeback ...
So of course the question should be modified: modeling the type without mixed feeback would need a resonance of = 0 ?

Similar topic:
For the tube amp experts: the Marshall Major features a so-called "ultralinear design" output stage, which is characterized by a significantly reduced output resistance --> increased damping factor. Anybody here with the technical background to give an estimate on an appropriate damping factor / resonance setting to emulate this ?

Sorry if my English is funny - not a native speaker.
 
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FractalAudio said:
The resonance Q is a bit more difficult to calculate. It is derived from the bandwidth at the points where the impedance "gain" is the square root of the resonance impedance gain. IOW, if the impedance is, say, 10 times the nominal impedance then the bandwidth is given by the frequencies where the response is 3.16 times the nominal impedance. For our example the resonance gain is 5 (40 / 8 = 5). So the bandwidth is the frequencies at which the impedance equals sqrt(5) * 8 = 18. From the graph this is approximately 75 Hz and 130 Hz. Q is defined as f0 / bw so our resulting Q is 100/60 = 1.67. Most speakers have a Q of around 2.0 or so. Again the exact value isn't overly critical and don't be afraid to try extreme settings (you can't break anything).
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@FractalAudio

Please confirm my math:

144 ohm (resonance peak impedance).
96Hz (resonance frequency).
14 ohm (nominal impedance).

144/14 = 10.3
sqrt(10.3) * 14 = 45 ohm

At 45 ohm: 80Hz, 113Hz (from graph).
BW: 113 - 80 = 33

Q = Rf/BW = 96/33 = 2.9
 
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James Freeman said:
@FractalAudio

Please confirm my math:

144 ohm (resonance peak impedance).
96Hz (resonance frequency).
14 ohm (nominal impedance).

144/14 = 10.3
sqrt(10.3) * 14 = 45 ohm

At 45 ohm: 80Hz, 113Hz (from graph).
BW: 113 - 80 = 33

Q = Rf/BW = 96/33 = 2.9
Click to expand...
Here are the values:
LF Res Freq: 96.5
LF Res Q: 1.55
LF Resonance: 8.96

HF Res Freq: 1253
HF Resonance: 7.51
HF Slope: 2.9

I don't want to publish the math because then someone can reverse engineer our curves.
 
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