Hi. I have some measurements voltage vs current here. Current drive for better sound | Baffless
I don't work with closed boxes or passive crossovers so in that case things can be a lot different probably.
But for open baffle current drive produces less distortion in acoustic signal for sure. It is also dependant on the driver. I have measured 3 different drivers and all of them measures better with current drive. At Fs i saw both ways. One driver performs better with voltage another with current.Thats measuring. Thats why i am developing current drive amp which has the possibility to use voltage drive at Fs. Prototype works so it is just a matter of time when i will make more measurements. This summer for sure.
For my ears sound is better with current drive for sure, that is why i am using them.Also sound is very pleasant with kind of "velocity feedback" derived from voltage and current. I have experimented a little, but put aside this idea for now. Measurements are not better.About the same o worse, but the sound is very very interesting.Just can't do any conclusions.
Have in mind that equalizing voltage and current drive for the same FR will not provide the same impulse response. Unless you use kirkeby inverse or alternative methods. So around Fs you get very different time domain picture with undamped resonance frequency. That could be one of the reasons for a good sound. But even with perfect impulse inverse current drive is what i prefer a lot. It just introduce latency in DSP.
Also current drive could be a passive solution for open baffle fast roll off at low frequencies. Cheap and nice solution for diy open baffles🙂
Voltage is just the reason for the current to appear. And the current makes things to move. You can have voltage but no current and no work done. Sadly that all audio drivers are designed for voltage drive.
I don't work with closed boxes or passive crossovers so in that case things can be a lot different probably.
But for open baffle current drive produces less distortion in acoustic signal for sure. It is also dependant on the driver. I have measured 3 different drivers and all of them measures better with current drive. At Fs i saw both ways. One driver performs better with voltage another with current.Thats measuring. Thats why i am developing current drive amp which has the possibility to use voltage drive at Fs. Prototype works so it is just a matter of time when i will make more measurements. This summer for sure.
For my ears sound is better with current drive for sure, that is why i am using them.Also sound is very pleasant with kind of "velocity feedback" derived from voltage and current. I have experimented a little, but put aside this idea for now. Measurements are not better.About the same o worse, but the sound is very very interesting.Just can't do any conclusions.
Have in mind that equalizing voltage and current drive for the same FR will not provide the same impulse response. Unless you use kirkeby inverse or alternative methods. So around Fs you get very different time domain picture with undamped resonance frequency. That could be one of the reasons for a good sound. But even with perfect impulse inverse current drive is what i prefer a lot. It just introduce latency in DSP.
Also current drive could be a passive solution for open baffle fast roll off at low frequencies. Cheap and nice solution for diy open baffles🙂
Voltage is just the reason for the current to appear. And the current makes things to move. You can have voltage but no current and no work done. Sadly that all audio drivers are designed for voltage drive.
Hi Baffless,
You puzzle me: equalizing voltage and current for the FR will not provide the same impulse response.
Would you be so kind as to show the measurements? In my book amplitude and phase are always linked, so I am really curious to see otherwise.
You puzzle me: equalizing voltage and current for the FR will not provide the same impulse response.
Would you be so kind as to show the measurements? In my book amplitude and phase are always linked, so I am really curious to see otherwise.
Two situations in example. voltage and current drive at resonant frequency. Very different. If you stop voltage in voltage amp the cone will stop very fast , if you stop current in current amp it will oscillate quite long. Damping is different about 10 times.
What i have is this. It's above resonance. At Fs oscillations would be longer.
What i have is this. It's above resonance. At Fs oscillations would be longer.
Yes that my sentence should be corrected. It is confusing. I by default separate phase from frequency in my mind. So if someone say that corrected FR i think they left phase as it was and corrected only frequency.
But a frequency response has two parts, the magnitude response and the phase response. They are linked together.
If you change the frequency response (magnitude) you also change the phase response, you can't manipulate them separately (except with some digital IIR techniques which is not the case here I believe).
So how can you separate frequency response (magnitude) and phase response in any meaningful way?
Jan
If you change the frequency response (magnitude) you also change the phase response, you can't manipulate them separately (except with some digital IIR techniques which is not the case here I believe).
So how can you separate frequency response (magnitude) and phase response in any meaningful way?
Jan
@Jan: precisely my point.
Baffles: would you be so kind as to show overlays of the -claimed- identical amplitude plots with some detail, say 2 dB/div?
Baffles: would you be so kind as to show overlays of the -claimed- identical amplitude plots with some detail, say 2 dB/div?
Depends on the filter type you use. You can manipulate phase and frequency separetly. In Rephase you can try it. There is separate section for phase and frequency manipulating. FIR Filters are nice thing just latency is added
Nobody denies the possibilities of FIR filtering. I was under the impression we were talking analogue systems..
I think the question is still, should an impulse from an equalised response (IIR, mag and phase like jan/Boden suggest because the system is a linear one and that's what it requires), so the response is the same when driven by a V source or an I source, be any different?
@Scottjoplin - true, but the magnitude response and the phase response are still locked together (in analog filters). Change one, you change the other.
It's a no brainer: if you do a low pass, you have to accept a change in phase response. You cannot do (in analog) a low pass filter rolling off the magnitude response without changing the phase response as well.
Jan
It's a no brainer: if you do a low pass, you have to accept a change in phase response. You cannot do (in analog) a low pass filter rolling off the magnitude response without changing the phase response as well.
Jan
I'd agree that linearity would be the main difference. Frequency response and transient response, same thing..
Didn't Baffless say the impulses shown were different and they'd been EQed in response but not phase using FIR?
Didn't Baffless say the impulses shown were different and they'd been EQed in response but not phase using FIR?
