Hi!
I've been trying to figure out Gunnes Focusing https://www.fulcrum-acoustic.com/assets/pdf/whitepapers/improving-loudspeaker-transient-response-with-dsp-2005.pdf . One scenario mentioned in the paper is to remove some LTI reflections from compression driver and horn combination. I had an idea if some of the horn reflections Gunnes is fixing could be measured with the compression driver itself, since I can't imagine I could measure them (or identify them from a measurement ) with a measurement microphone.
Anyway, I've been using a simple 1.5v battery + toggleswitch to provide a transient signal to a compression driver and record the impulse with mic pre connected to the driver terminals. The measurement shows all kinds of resonances, since there is no damping for the driver other than the mic leads attached (with U-pad). Some of the resonances measured must be the driver diaphragm resonating, but there might be the horn reflections recorded as well.
My procedure has been like this: switch the battery on, start measurement (ARTA) procedure and switch the battery of to get an impulse measured. The driver is not in normal position when doing it like this, since there is DC potential while starting the measurement / transient.
Tried to use amplifier to provide a proper signal from computer, but cannot measure simultaneously, amplifier dampens the whole thing.
I was wondering if there was a simple (or complicated) electrical circuit that would enable me to switch the signal generating part effectively out from the circuit (DUT) automatically after the transient signal is over and before the reflections happen so that the measurement of the reflections could be taken?
Round trip from diaphragm to horn throat and back would be maybe ~10cm, ~0,3ms, so the transient should be over and "signal generator" out from the circuit before that.
Signal could be provided through a power amp, or with a battery + some circuitry to get DC free impulse.
I've found out that a Monostable multivibrator could provide a transient, but cannot figure out how to best utilize it in this application. I tried quick simulation of simple battery + capacitor + switch jig with TinkerCAD for DC free transient, but the capacitor would be in parallel with the driver while taking measurements so probably not worth trying. Also TinkerCAD has only piezo speaker in the library, impedance of which is unknown, and didn't have time to make electrical model of a speaker driver with passive components So, thought to ask from the GroupDIY for tips.
Thanks, any feedback welcome!
I've been trying to figure out Gunnes Focusing https://www.fulcrum-acoustic.com/assets/pdf/whitepapers/improving-loudspeaker-transient-response-with-dsp-2005.pdf . One scenario mentioned in the paper is to remove some LTI reflections from compression driver and horn combination. I had an idea if some of the horn reflections Gunnes is fixing could be measured with the compression driver itself, since I can't imagine I could measure them (or identify them from a measurement ) with a measurement microphone.
Anyway, I've been using a simple 1.5v battery + toggleswitch to provide a transient signal to a compression driver and record the impulse with mic pre connected to the driver terminals. The measurement shows all kinds of resonances, since there is no damping for the driver other than the mic leads attached (with U-pad). Some of the resonances measured must be the driver diaphragm resonating, but there might be the horn reflections recorded as well.
My procedure has been like this: switch the battery on, start measurement (ARTA) procedure and switch the battery of to get an impulse measured. The driver is not in normal position when doing it like this, since there is DC potential while starting the measurement / transient.
Tried to use amplifier to provide a proper signal from computer, but cannot measure simultaneously, amplifier dampens the whole thing.
I was wondering if there was a simple (or complicated) electrical circuit that would enable me to switch the signal generating part effectively out from the circuit (DUT) automatically after the transient signal is over and before the reflections happen so that the measurement of the reflections could be taken?
Round trip from diaphragm to horn throat and back would be maybe ~10cm, ~0,3ms, so the transient should be over and "signal generator" out from the circuit before that.
Signal could be provided through a power amp, or with a battery + some circuitry to get DC free impulse.
I've found out that a Monostable multivibrator could provide a transient, but cannot figure out how to best utilize it in this application. I tried quick simulation of simple battery + capacitor + switch jig with TinkerCAD for DC free transient, but the capacitor would be in parallel with the driver while taking measurements so probably not worth trying. Also TinkerCAD has only piezo speaker in the library, impedance of which is unknown, and didn't have time to make electrical model of a speaker driver with passive components So, thought to ask from the GroupDIY for tips.
Thanks, any feedback welcome!