I saw that there are some threads that talk about the ace bass system, in particular referring to the patents: US 4118600 and US 4797933.
I would like to create such a system with a DSP like adau1701 and since I have no experience with DSPs in general I ask if anyone has already created something like this and if it is possible
I would like to create such a system with a DSP like adau1701 and since I have no experience with DSPs in general I ask if anyone has already created something like this and if it is possible
I suppose with a good ADC, you could. But its quite straight forwards I think and I'm not sure a DSP would add anything really... Kalle took charge of the physical entities by representing them in R, C and L... what more do you want?
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I may misunderstand the OP intention. With DSP you can equalize the frequency response to look alike ACE Bass response, but it is not the same thing as changing the woofer Qts parameter with ACE Bass circuit, for example. Or the intention is to replace all analog circuitry of ACE Bass (except the sensing feedback resistor) with DSP?
If you have read through the threads related to ACE-BASS via DSP you probably have seen the problem: latency. Latency through the ADC+DSP loop produces phase shift. At some (higher) frequency this phase shift will result in positive feedback and the system will be unstable. Even with a "fast" hardware DSP processor this frequency might be only a few hundred Hertz. All frequency content must be eliminated well below this frequency, and that can restrict the performance. Make sure to study this problem carefully before you attempt such a feedback system using DSP.
in fact that was my intention. leave current feedback opamp (ACE2) and replace the other opamps which seem to me to be only band pass (ACE1), high pass (HP) and all pass (AP), with reference US497933 fig.4
@ CharlieLaub
I haven't read the threads related to ACE-BASS via DSP,
Could you give me the links, please?
I haven't read the threads related to ACE-BASS via DSP,
Could you give me the links, please?
My problem is that I failed the simulation referred to in figs. 5a and 5b of US4118600.
In the treads I found the formulas provided by Baldin, but they are not correct, or maybe I'm wrong? (I studied the theory 50 years ago and now it's difficult for me to remember it)
In the treads I found the formulas provided by Baldin, but they are not correct, or maybe I'm wrong? (I studied the theory 50 years ago and now it's difficult for me to remember it)
"The plurality of parallel impedances have values which cause the loudspeaker to exhibit apparent mechanical parameters which are substantially different from the actual mechanical parameters in the bass response of the loudspeaker"
if the goal is to change the apparent mechanical parameters to achieve a better response - e.g. boost the low end - why do it with feedback when it can be done with a Linkwitz transform (feedforward / equalization) ???
Its Hoffman's iron law either way
if the goal is to change the apparent mechanical parameters to achieve a better response - e.g. boost the low end - why do it with feedback when it can be done with a Linkwitz transform (feedforward / equalization) ???
Its Hoffman's iron law either way
Sorry, didn't read closely enough to realize you were talking bass reflex.
My suggestion for BR is simply to change the Q of the high pass filter. Your bass reflex needs a high pass filter. Typically one uses a filter with a Q of .707., e.g LR filters. To boost at/just above the cutoff frequency just raise the Q. easy to do in DSP and to see the results in simulation.
My suggestion for BR is simply to change the Q of the high pass filter. Your bass reflex needs a high pass filter. Typically one uses a filter with a Q of .707., e.g LR filters. To boost at/just above the cutoff frequency just raise the Q. easy to do in DSP and to see the results in simulation.