Analog vs digital input for a class D amplifier?
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An Edifier rep told me that the signal conversion process inside their bookshelf speakers with a class D amp would be more like an ADC (analog to digital converter) which made me think giving it a digital signal would be better, but after looking into myself I thought it still made more sense that the conversion from an analog signal to PWM is less lossless than giving the class D amp a digital signal. My rationale is that PWM in a class D amp is more like converting one type of analog version to another type of analog, not analog to digital, in which case the speakers are doing more processing on the signal, but I don't really know.

So is it better to go digital or analog input on a class D amp, or are both about the same? Can the design implementation affect which is better in a particular set of speakers?
 
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You didnt list the model of the edifier speakers, but I'm assuming that they have a built in digital to analog converter (dac). I do not know if it also included analog inputs as well, but I would hope that it would. Basically, if you already have a dac that you are using and are happy with, then use it and hook it up to the analog inputs if available on the speakers. If the speakers do not have analog inputs or you want to try their on board dac, hook your source (pc, cd player, etc) straight to one of the digital connections on the speakers (usb, optical, coax, etc) and do not use your dac at all. I'm not even sure there is a standalone device for changing analog sound to digital on the fly like what is mentioned (although I may be wrong here) but I would strongly advise against using such if it did exist.
 
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It's the Edifier R1280DB. It has RCA analog inputs, digital coax and optical inputs. This is more about a class D amplifier and what is the most lossless way to send a signal to it assuming the digital and analog source signals would be theoretically the same quality (which usually isn't the case however), if there even actually is a difference? I was just a bit thrown off by the Edifier rep saying that the class D amp accepts a digital signal directly but that an analog signal needs to be converted to digital for the class D amplifier.

According to the wikipedia article on class D amplifiers, "It is also possible to synchronize the modulator clock with an incoming digital audio signal, thus removing the necessity to convert it to analog. " So it's possible that the amp in these speakers was only designed to directly accept a digital signal even though it is possible to implement class D amps to accept either one or both. So in this particular model, apparently the analog input signal is being converted to digital before the amplifier, even though it doesn't necessarily need to be so in all class D implementations.
 
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flailure

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Yeah, that rep makes no sense, amplifiers amplify, they do not convert. Unless an amplifier has some sort of digital to analog converter before it, it does not take a digital signal in. Do not take an analog signal and convert it to digital just so that the speakers can re convert it to analog, that makes no sense.
 
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What do you think about this? https://en.wikipedia.org/wiki/Class-D_amplifier#Basic_operation
"It is also possible to synchronize the modulator clock with an incoming digital audio signal, thus removing the necessity to convert it to analog."

PWM is strange because it uses an on/off operation mode coupled with length of time to represent amplitude, so it's like half digital half analog in how it works. I remember reading a bit about it and still don't completely understand how or why it works.
 
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flailure

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I would not convert an analog signal to digital for that, its just another way of processing. If, however, you already have a digital signal you want to run this way be my guest, just follow the manufacturers instructions on how to input it for it to function.
 
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An Edifier rep told me that the signal conversion process inside their bookshelf speakers with a class D amp would be more like an ADC (analog to digital converter) which made me think giving it a digital signal would be better, but after looking into myself I thought it still made more sense that the conversion from an analog signal to PWM is less lossless than giving the class D amp a digital signal. My rationale is that PWM in a class D amp is more like converting one type of analog version to another type of analog, not analog to digital, in which case the speakers are doing more processing on the signal, but I don't really know.

So is it better to go digital or analog input on a class D amp, or are both about the same? Can the design implementation affect which is better in a particular set of speakers?
I would suggest not to obsess about conversion, and just enjoy how convenient it is to have all those inputs options. My opinion comes from the idea that most AD DA operations are a lot more accurate than what a transducer does to an electrical signal. So it shouldn't be worrisome to have them applied one extra time, as they probably still won't be the weak link in the chain.
Some really cool speakers do that, sometimes before applying super duper fancy onboard DSPs. I guess old school purists hear about that and pull out a cross to push back all the evil thoughts contained in the design of such products, but modern audiophiles who understand a little more about sampling and reconstruction should have no reason to fear conversions in either directions.
 
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Yeah, that rep makes no sense, amplifiers amplify, they do not convert. Unless an amplifier has some sort of digital to analog converter before it, it does not take a digital signal in. Do not take an analog signal and convert it to digital just so that the speakers can re convert it to analog, that makes no sense.
It is a common scenario today to convert analog to digital and back to analog. Many powered speakers (even small desktop models) use a DSP chip to equalize the frequency response and implement high and low pass crossover filters in the digital domain. When analog input is used, it will be first digitized before going to the DSP. Actually many DSP chips take analog signals directly and have the digitizer integrated into the chip.

So is it better to go digital or analog input on a class D amp, or are both about the same? Can the design implementation affect which is better in a particular set of speakers?
The implementation always matters. Try both inputs and see if one sounds better than the other on your speakers.
 
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I doubt it makes any difference.
 
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