Emperor-TK
Well-known member
I just got a new toy at work, which led me to think about a new (I think) compressor topology... the chemical compressor. Before I start, let me just say that I'm not going to build this, or even research it. I don't think that it will be simple or practical, just interesting as a concept. I'm just presenting this idea as a curiosity.
I just purchased a new pH meter for field use, and the probe that goes with this meter is a solid state design known as an ISFET (ion sensitive FET). As I understand it, the traditional transistor gate is replaced with a proton sensitive layer that will adjust the source-drain current proportionally to the concentration of H+ ions in the solution. Some of the aqueous surfactant systems that I work with are sheer sensitive, where the surfactant phase orderings change with physical disturbances, and as a consequence, the amount of free ions (including H+) in the bulk aqueous phase changes proportionally. Hypothetically, I can make up one of these solutions, insert an audio transducer as a way of imparting sheer, and measure the change in pH as a function of the audio's amplitude (and possibly frequency) with the ISFET.
I suspect that the slow response time of the ISFET probe and the aqueous system itself are pretty much deal breakers for a practical compressor, along with strong hysteresis in the solution. However, I suspect that it might be possible to make one with limited functionality (with attack and release times on the order of 10-30 seconds). The ISFET is what put the compressor idea in my head, but a traditional 19th century electrochemical pH probe would work too, generating a voltage differential as a function of acoustic sheer. My system might even work directly as half of an electrochemical cell.
Imagine running a session where you need to add a little more vinegar to the compressor to get it to sound the way you like. Would threads at the lab read like "what's better to mod my compressor, malt vinegar or distilled white'? Malt vinegar of course sounds warmer, distilled white is clearer and more open sounding. :green:
-Chris
I just purchased a new pH meter for field use, and the probe that goes with this meter is a solid state design known as an ISFET (ion sensitive FET). As I understand it, the traditional transistor gate is replaced with a proton sensitive layer that will adjust the source-drain current proportionally to the concentration of H+ ions in the solution. Some of the aqueous surfactant systems that I work with are sheer sensitive, where the surfactant phase orderings change with physical disturbances, and as a consequence, the amount of free ions (including H+) in the bulk aqueous phase changes proportionally. Hypothetically, I can make up one of these solutions, insert an audio transducer as a way of imparting sheer, and measure the change in pH as a function of the audio's amplitude (and possibly frequency) with the ISFET.
I suspect that the slow response time of the ISFET probe and the aqueous system itself are pretty much deal breakers for a practical compressor, along with strong hysteresis in the solution. However, I suspect that it might be possible to make one with limited functionality (with attack and release times on the order of 10-30 seconds). The ISFET is what put the compressor idea in my head, but a traditional 19th century electrochemical pH probe would work too, generating a voltage differential as a function of acoustic sheer. My system might even work directly as half of an electrochemical cell.
Imagine running a session where you need to add a little more vinegar to the compressor to get it to sound the way you like. Would threads at the lab read like "what's better to mod my compressor, malt vinegar or distilled white'? Malt vinegar of course sounds warmer, distilled white is clearer and more open sounding. :green:
-Chris
