Hello everyone
For my study project, I'd like to simulate the Larsen Effect (feedback) which occurs when the guitar is too close to the amplfier.
So, I'd like to simulate my guitar amplifier (Marshall MG10) by following this schematic : ElectroSmash - Marshall MG10 Analysis.
First of all, is mine correct ? (attached file)
I simulate the speaker with the Thiele&Small parameters provided on the electrosmash website, and do an equivalent circuit, but i'm note sure if that's correct...
So, the aim is to calculate the frequencies for which the feedback occurs.
But I have no idea where to start 😕
I'd would like to show the influence of the Distance between the guitar pickup and the speaker, the Gain/Volume, and the Angle between the pickup and the speaker axis.
So I assume I should close a loop somewhere to model the positive feedback...
Then after the simulation, I'd would like to compare with my measures in real life.
Can anyone suggest me something ? I'd appreciate it 🙂
Thx ! (sorry for the poor English)
For my study project, I'd like to simulate the Larsen Effect (feedback) which occurs when the guitar is too close to the amplfier.
So, I'd like to simulate my guitar amplifier (Marshall MG10) by following this schematic : ElectroSmash - Marshall MG10 Analysis.
First of all, is mine correct ? (attached file)
I simulate the speaker with the Thiele&Small parameters provided on the electrosmash website, and do an equivalent circuit, but i'm note sure if that's correct...
So, the aim is to calculate the frequencies for which the feedback occurs.
But I have no idea where to start 😕
I'd would like to show the influence of the Distance between the guitar pickup and the speaker, the Gain/Volume, and the Angle between the pickup and the speaker axis.
So I assume I should close a loop somewhere to model the positive feedback...
Then after the simulation, I'd would like to compare with my measures in real life.
Can anyone suggest me something ? I'd appreciate it 🙂
Thx ! (sorry for the poor English)
That's a very interesting idea for a project, but also could be very ambitious as a significant amount of sophisticated modelling will be needed.
The effect of distance between guitar and speaker could be modelled as a pure time delay, which results from the speed of sound.
One thing you didn't mention is that you also need a model of a guitar string and the pick-up. (The sound from the speaker forces the string to vibrate, and the resulting variation of magnetic reluctance in the 'magnetic flux circuit' of the pick-up causes an induced voltage signal in the pick-up coil.)
There is also a type of feedback which would occur even without any strings, in which the pick-up is microphonic, but this (should) only occur when the pickup is close to
the speaker and it is a non-musical high-pitched squeal.
I think it may even be possible to get another type of feedback, when the pick-up is extremely close to the speaker coil, by direct magnetic coupling. (Not recommended!)
I would suggest starting with extremely simple models of the various subsystems and progressively enhancing the accuracy of these models. That way you will have some results to show from an early stage in the project.
The effect of distance between guitar and speaker could be modelled as a pure time delay, which results from the speed of sound.
One thing you didn't mention is that you also need a model of a guitar string and the pick-up. (The sound from the speaker forces the string to vibrate, and the resulting variation of magnetic reluctance in the 'magnetic flux circuit' of the pick-up causes an induced voltage signal in the pick-up coil.)
There is also a type of feedback which would occur even without any strings, in which the pick-up is microphonic, but this (should) only occur when the pickup is close to
the speaker and it is a non-musical high-pitched squeal.
I think it may even be possible to get another type of feedback, when the pick-up is extremely close to the speaker coil, by direct magnetic coupling. (Not recommended!)
I would suggest starting with extremely simple models of the various subsystems and progressively enhancing the accuracy of these models. That way you will have some results to show from an early stage in the project.
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