Thanks Hugo.
Marcel: there is never any feedback from the loudspeaker to the speakerdriver. This is why digitally driving the speaker (through reconstruction filter) won't work (or poor quality sound) (?) This is why "digitally" (meaning yes/no brickwall rail to rail edges on a discrete clock) driving the speaker at 320 kHz is too low, and should be done e.g. at 2.8 MHz. (?)
Marcel: there is never any feedback from the loudspeaker to the speakerdriver. This is why digitally driving the speaker (through reconstruction filter) won't work (or poor quality sound) (?) This is why "digitally" (meaning yes/no brickwall rail to rail edges on a discrete clock) driving the speaker at 320 kHz is too low, and should be done e.g. at 2.8 MHz. (?)
When there is no feedback from the loudspeaker, that means that any imperfections of the output stage and the power supply directly impact the output signal. You are then basically making a power DAC with the power supply as voltage reference. It will work, but it will be difficult to achieve very good sound quality.
I think it makes more sense to drive a class-D stage with a pulse-width modulator or with a sigma-delta modulator with an embedded pulse-width modulator than with a plain old single-bit sigma-delta modulator. The switching frequency can then be much lower, for example 320 kHz instead of 2.8 MHz, which hopefully leads to less disturbances on the power supply/voltage reference. I have zero experience with class-D amplifiers, though.
Hans, it is up to you, but maybe you would get more answers from people with experience with class-D amplifiers if you had the part from post #8 onward split off and put in a separate thread in the class-D subforum. You can type a request for that and use the Report button to send it to the moderators.
I think it makes more sense to drive a class-D stage with a pulse-width modulator or with a sigma-delta modulator with an embedded pulse-width modulator than with a plain old single-bit sigma-delta modulator. The switching frequency can then be much lower, for example 320 kHz instead of 2.8 MHz, which hopefully leads to less disturbances on the power supply/voltage reference. I have zero experience with class-D amplifiers, though.
Hans, it is up to you, but maybe you would get more answers from people with experience with class-D amplifiers if you had the part from post #8 onward split off and put in a separate thread in the class-D subforum. You can type a request for that and use the Report button to send it to the moderators.
I remember that about ten years ago there was an announcement for a speaker that had many coils, and each coil is driven by an amplifier such as ( my catch) each is a Bit part of a Byte. Clarion had a flyer explaining it. I don't see it applied, even if it was for car. Maybe graphene is the new thing applied to loudspeaker technology...I dunno!?
So that was a system for a compact all digital way to make sounds. Probably the speaker part had not been resolved. But I 'm unaware of today's progress in digital, in general...Like Mp3 and the likes, also in video. But I believe we are leaded, hence the progress in science and technology, by what satisfies most (our senses) so sort of natural selection.
Sort of...
Sort of...
Motorola wasn't sold to Freescale. Freescale was created from Motorola's semiconductor business.
Maybe using only 1 speaker and many coils was a way to eliminate crossover-circuits? I idn't look into Clarion.
"all digital", so more than 1 class-D (amplifying) ADCs involved?
You're right, I hadn't heard of Freescale before I discovered the Motorola DSP56001 datasheet suddenly had a "changed manufacturer"...
My new project, involving a class-D amplifying DAC, will be equiped with some sort of DSD output. Investigating what format to use, I came across https://en.wikipedia.org/wiki/Direct_Stream_Digital#DSD_embeds_in_PCM_based_file_formats, where it says:
"... A DoP stream is designed to sound like low volume noise when played back by a PCM-only DAC..."
"Exactly" like in my MP3-player-before-it-existed, post #2: "... My data sounded as noise, but luckily the Marantz could handle it (input by S/PDIF)..."
(!!!)
"... A DoP stream is designed to sound like low volume noise when played back by a PCM-only DAC..."
"Exactly" like in my MP3-player-before-it-existed, post #2: "... My data sounded as noise, but luckily the Marantz could handle it (input by S/PDIF)..."
(!!!)
Works something like this?:
https://www.audiosciencereview.com/forum/index.php?search/43463138/&q=josedgm&o=relevance
Didn't look into Clarion yet; going to view above https now...