Associate
- Joined
- 27 Apr 2004
- Posts
- 2,377
Thinking about hifi equipment earlier, and ways to improve sound quality, I had an idea for an amp & driver combo.
It's based on the assumption that the transient response of an amp plays a significant role in determining the sound quality. So I wondered, how can you improve the transient response?
Now, I really have no idea whether this system would work, and more importantly, whether it would sound any better than existing types - and that's why I'm posting here, to see if anyone has ever seen anything similar, or had similar ideas. Just wanting criticism I suppose, to see whether its feasible.
With that said, I'll describe the idea. The transient response is improved by only ever applying the full rated voltage to the drivers, so as to exert maximum force on the cone; the driver is either compressing or rarefying at full velocity.
Because we listen to sound pressure levels, not voltages, the driver has a microphone mounted in front of it (though I suppose it could be mounted internally too?); it should produce better sound by perfecting the pressure output, rather than the driving voltage.
The output of this feedback microphone, and the input signal voltage, are connected to a comparator (as shown below). The output of this comparator will thus be high (if the driver must compress more to achieve the correct pressure level) or low (if the driver must rarefy to achieve the correct pressure level).
This output is then used to continually switch the direction of the current driving the driver (using a MOSFET H-Bridge), and the overall effect is that the pressure level follows the input voltage.
Here's a schematic.
I am aware of several pitfalls of this idea; because the amp uses the output of the driver in order to run, it would be necessary to have one amp for each driver, and these would have course have to be after the (active) crossovers.
Also due to the cost and difficulty of sourcing suitable P-Type MOSFETs, I have used N-Types throughout the H-Bridge; those acting as current sources would require a higher gate voltage than provided by the output of the comparator - this could be achieved with a voltage doubler, which I have not included for the sake of simplicity.
Am I crazy or could this work?
It's based on the assumption that the transient response of an amp plays a significant role in determining the sound quality. So I wondered, how can you improve the transient response?
Now, I really have no idea whether this system would work, and more importantly, whether it would sound any better than existing types - and that's why I'm posting here, to see if anyone has ever seen anything similar, or had similar ideas. Just wanting criticism I suppose, to see whether its feasible.
With that said, I'll describe the idea. The transient response is improved by only ever applying the full rated voltage to the drivers, so as to exert maximum force on the cone; the driver is either compressing or rarefying at full velocity.
Because we listen to sound pressure levels, not voltages, the driver has a microphone mounted in front of it (though I suppose it could be mounted internally too?); it should produce better sound by perfecting the pressure output, rather than the driving voltage.
The output of this feedback microphone, and the input signal voltage, are connected to a comparator (as shown below). The output of this comparator will thus be high (if the driver must compress more to achieve the correct pressure level) or low (if the driver must rarefy to achieve the correct pressure level).
This output is then used to continually switch the direction of the current driving the driver (using a MOSFET H-Bridge), and the overall effect is that the pressure level follows the input voltage.
Here's a schematic.
I am aware of several pitfalls of this idea; because the amp uses the output of the driver in order to run, it would be necessary to have one amp for each driver, and these would have course have to be after the (active) crossovers.
Also due to the cost and difficulty of sourcing suitable P-Type MOSFETs, I have used N-Types throughout the H-Bridge; those acting as current sources would require a higher gate voltage than provided by the output of the comparator - this could be achieved with a voltage doubler, which I have not included for the sake of simplicity.
Am I crazy or could this work?
