dunghnguyen wrote:@PeterB: Hi bro! It seems I found something out from you here since you were aware I am a newbie in one another thread in this Rune forum.
I intend to build Rune like a transport to play 2 channels audio controlled by smartphone so I am considering about the HiFiBerry DAC+. I wish to be shared from you:
- it has 3 ports out of coaxial / optical / USB ?
- it is 24 bit / 192kHz ?
- about its sound quality?
- the original HDMI output signal of Pi2 seems low, I tried it out to Yamaha receiver that I felt really low compare to Kodi case to play, hope it is better in case of HiFiBerry DAC+ ?
First, I have no idea why the analog output seems to be low. There may be something you can do to improve it, but you also have to consider what the output is driving (connected to).
The Pi alone (with no addon board) has a very basic analog output which uses PWM (pulse-width-modulation) instead of a modern DAC. You get at most 10-bit quality with a low SNR (signal-to-noise ratio). Not intended for hifi, not by itself.
By comparison, the HiFiBerry DAC+, or the IQ Audio DAC, or any similar DAC that you add on to the Pi is much, much better. They are capable of 24-bit/192KHz.
I can't really hear the difference between a good source file encoded at a lower resolution and frequency and 24/192, not like I can hear the difference between a typical MP3 and lossless wav or flac. No way I am ripping my library again just to get 24/192 files
The sound quality of most addon boards is very good, with little or no audible distortion, flat to well over 20KHz, because the typical DAC chip used on these boards does not require an aggressive low-pass filter. This also means there is little or no time-domain distortion. The downside is that if you have headphones which accentuate high frequencies (like typical Sennheiser headphones for example), then highs will seem bright compared to other sources. If you have headphones which are essentially flat like my AKGs, it will sound natural. With most speakers you will not be able to tell. Mid-highs, mids, and bass are all very natural.
There are two types of output boards. One kind has the S/PDIF digital outputs (COAX and optical), and the other kind has RCA analog outputs, basically a line-out to a preamp, receiver, amp, etc. You get one or the other, not both.
The third type of board is an integrated DAC and class-D amplifier. That was the original subject of this thread.