Usually we are talking about the average density of 1's in a stream of bits.
However, one bit can have a value of 0 or a 1. If the bit a 1, then its density of 1's is 100%. If its a 0 then the density of 1's is 0%.
However, one bit can have a value of 0 or a 1. If the bit a 1, then its density of 1's is 100%. If its a 0 then the density of 1's is 0%.
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Right.
Usually we LP filter the bitstream to get the analog output of a DSD dac. Assuming its running in PDM mode (Pulse Density Modulation). Sometimes we might be able to operate the dac in PWM mode instead, but we still LP filter it.
Usually we LP filter the bitstream to get the analog output of a DSD dac. Assuming its running in PDM mode (Pulse Density Modulation). Sometimes we might be able to operate the dac in PWM mode instead, but we still LP filter it.
Cool...so I was thinking of playing around with a PDM mic.
I kinda wanted to go like this:
PDM mic -> Intel i7 windows PC --> DSD512 file
Without DAC /PCM conversion . LP filters etc ok.
I kinda wanted to go like this:
PDM mic -> Intel i7 windows PC --> DSD512 file
Without DAC /PCM conversion . LP filters etc ok.
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A DSD dac is typically clocked at some frequency (because all dacs need a time reference and also a voltage reference). For DSD512, the DSD clock (BCLK in common I2S parlance), is usually clocked at 22.5792MHz or at 24.576MHz (which may be notated as DSD512/44 or DSD512/48). First question might be whether if your PDM mic is clocked or free running? If clocked, then at what frequency?
There could be some other questions after that, but probably good to start with some basic stuff.
There could be some other questions after that, but probably good to start with some basic stuff.
Thanks Mark.So it can be done - PDM mic -> DSD without PCM ?
All I have ATM is the DSD DAC (Ultimate Stars Dual AK4495 384KHz 32Bit DSD DAC ) and a (good) Windows machine.
What PDM mic would be good for my application?
Cheers
All I have ATM is the DSD DAC (Ultimate Stars Dual AK4495 384KHz 32Bit DSD DAC ) and a (good) Windows machine.
What PDM mic would be good for my application?
Cheers
Well, its not quite that simple. A dac like AK4495 is probably not a real DSD dac any more than its a real PCM dac. Most dac chips like that operate internally in some mode that might be described as PCM-Narrow or DSD-Wide. IOW, its maybe a 5-bit dac that is oversampled to make it perform like the equivalent of a 24-bit PCM dac or else like a DSD dac. There are some finer details that could be discussed, like volume control bypass mode, dynamic element substitution, etc., but still some of how a particular chip dac works remains a company secret.
So far as I know there is maybe only one real DSD dac chip left, if it still is. Other than that, there are discrete resistor DSD dacs you can build.
Anyway, what is your purpose in all this? To record with a mic, to make a PA system, or what?
Reason I ask is there are probably some better ways to get results you want than you have thought to ask about so far, unless perhaps you already really know a lot about what you are doing in this area.
So far as I know there is maybe only one real DSD dac chip left, if it still is. Other than that, there are discrete resistor DSD dacs you can build.
Anyway, what is your purpose in all this? To record with a mic, to make a PA system, or what?
Reason I ask is there are probably some better ways to get results you want than you have thought to ask about so far, unless perhaps you already really know a lot about what you are doing in this area.
Thanks again Mark.
My DSD music files sound great thru my 'dsd dac' so it got me wondering if there's a future in pure pdm..
My purpose: With many affordable PDM mics on the market to play with, and as I have the capability to 'play' DSD files, maybe I could play around with PCMless digital audio , altho now it's not seemingly that simple..
Sorry, no grand plans to build PA /recording studio ATM
What is the 'real' DSD chip?
My DSD music files sound great thru my 'dsd dac' so it got me wondering if there's a future in pure pdm..
My purpose: With many affordable PDM mics on the market to play with, and as I have the capability to 'play' DSD files, maybe I could play around with PCMless digital audio , altho now it's not seemingly that simple..
Sorry, no grand plans to build PA /recording studio ATM
What is the 'real' DSD chip?