
RaspyFi - Pi never sounded so good - gglanzani
http://www.raspyfi.com/
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nichodges
I've been using this for a couple months now.

Setup was perfect, as per the instructions without anything weird popping up
(which has happened on every other Pi project I've done)

Streaming FLAC from a network drive was jumpy, so I bought a USB drive to plug
in which is loaded with my FLACs.

The Pi is plugged into a Scot Nixon USB Chibi DAC, and then a Rotel 1080 pre
and power amp.

I did some A/B tests comparing the Pi to an Airport Express running RCA's
directly into the pre amp, and the difference is huge. Lower noise floor, much
better separation, and a lot of detail. I'd suggest anyone who's wondering
should give it a go. Also the mPad app on iPad and iPhone works perfectly.

~~~
GotAnyMegadeth
Have you managed to get it working with Spotify?

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nichodges
Given I have an Airport Express as well - no. My PyFi is just for FLACs, I
still use the Express for radio/spotify/soundcloud.

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antocv
Great reuse of MPd/c instead of writing something else homemade.

I wonder why this isnt more easier, people love to listen to music, from
various sources to various speakers, sometimes I want to play it perhaps on my
phone whats available on the raspfi, and sometimes to play what is on the
phone but not on the NAS/usb-stick through the raspfi connected speakers
(without attaching wire to the phone), and this solution seems to falter
here... and sometimes I would like to give control of the playlist to a
friends phone, or play the music on his device through mine. Why are these
scenarios so difficult to do, it is 2013 and we have all the pieces? And yet
it is such a hassle. (How come everything sucks so much?)

Ive been trying for years now, without success. Its always some library or
quirk thats missing. Tomahawk-player is the best I came so far, together with
DLNA, but it doesnt have a good android client yet.

~~~
mikelangeloz
Hi, I'm RaspyFi founder. The points you made are exactly what we have in mind
for future releses: 1- multiple users playlist 2- multiroom support

Some of the things you mentioned can be already done. A friend of you can
enqueue songs on raspyfi's playlist. The PI can handle 10 simoultaneus clients
connected, that means also collaborative play queue. Hope you're enjoying
RaspyFi

~~~
antocv
Would it be possible to add a kind of auto-discover of a web-interface to
control the RaspFi? So that friends/guests dont have to install a client or
any other app, just by what is bundled on an android, I believe most already
have some kind of DLNA, Samsung S3 has it, but they call it Kies or ShareAll
or something. So a guest would discover the RaspFi, and control it/manage it
like any other dlna device. Do we need to develop some kind of adapter between
dlna - mpd?

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egeozcan
I happen to have a bunch of FiiO E10s a E07K-E09 combo and a raspberry sitting
idle. I can't even begin to tell how excited I am. I'll test this tonight
(that'll be, in 7 hours) and hopefully give an update on how things went.

~~~
egeozcan
After an hour of testing, I'd say it has some rough edges but audio-quality-
wise, it beats my windows 8 based setup (used e07k which is amplified by e09
in both). It must have been bit-perfect but this feels more spacious and
punchy, even. Maybe its the geekiness affecting my opinion. Haven't yet tested
the e07k on my mac mini though.

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ejstronge
I'm not familiar with using DACs to connect my digital gear to speakers. How
noticeable is the sound quality differnce?

I've used a 3.5mm to RCA cable to connect my computer to external speakers
before - is there something about the Raspberry Pi that would make this cable
a bad choice, or is using a DAC just an overall better choice for good sound
quality?

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harrytuttle
Musician (keyboard/synth) and ex Electrical Engineer here.

As usual, it depends.

In this case on how good the DAC and filtering is on the Pi. All an external
DAC does is move the concern away from the computer's built in DAC therefore
avoiding any noise and obvious distortion. It costs only a few $ so I'd
imagine the DAC/filtering is crap on the Pi.

However, if it sounds ok to you, it probably is ok. This is the main thing as
listening is subjective.

You can spend a fortune on making it sound better quality but there is little
return on this. Most of it is just prattery and rip off merchants.

From a recording versus listening point of view: don't worry too much. The
content is more important than the device reproducing it. Also the device that
produced the sound initially and the device that recorded it isn't necessarily
all that good quality and neither was the mixer monkey who compressed it to
fuck.

~~~
cnvogel
Yes, if it sounds ok, it's probably ok. But nevertheless, let me annoy
everyone with a few technical details:

Directly connected audio on the Raspberry PI is through a PWM output and
connected low-pass filter. It's implemented as a 10-bit timer (or so...) that
overflows at the audio sample rate (e.g. 48kHz), and the control value for the
PWM are the audio samples that are fed to the PWM block via DMA.

[http://www.raspberrypi.org/wp-
content/uploads/2012/02/BCM283...](http://www.raspberrypi.org/wp-
content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf) (page 138)

[http://www.raspberrypi.org/wp-
content/uploads/2012/10/Raspbe...](http://www.raspberrypi.org/wp-
content/uploads/2012/10/Raspberry-Pi-R2.0-Schematics-Issue2.2_027.pdf) (page
2, lower right)

Basially this means that...

1\. audio sample rate is limited to 48kHz because of the sample-rate/number-
of-bits tradeoff (it is not a real problem at all, but looks weak in a "audio
DAC" comparison)

2\. dynamic range is limited to 60dB, around the quality of cassette tapes
because we only have 10 PWM bits

3\. the PWM signal (square-waves) will have many high-order harmonics which
are not filtered well by the simple RC lowpass. Some of it might be mixed back
into the audible range by nonlinearities in your amplifier or your
loudspeakers, or at least waste power and unnecessarily heat up your
amplifier. Especially with Class-D (?) switched amplifiers this might be
audible.

~~~
cnvogel
I've checked the output with a scope: It's indeed a PWM signal, but not the
canonical PWM with fixed frequency and varying duty-cycle but something more
sophisticated. PWM nevertheless, probably there's some shaping being done by
the Videocore-Code (through which the audio data is routed).

I've tested the output with a sound-card (M-Audio Delta 44, via a Yamaha
MV12/4 Mixing console as preamp) that has (at the test-settings) a noise-floor
of ~-130dB/Hz. If I let the raspberry-pi play a sine-wave, I get harmonics at
~60-66dB down from full-scale.

I suspect that this is unshaped quantization noise, so this would compare the
suspicion that the PWM resolution is 11 or 12 bit.

Here's a screenshot of a frequency analyzer plugin running while recording the
audio output of the RPI, for comparison I put in the same sine being played by
the 16bit DAC of my mobile phone, here the harmonics are down -90dB or more.

[https://picasaweb.google.com/lh/photo/fWlV5aan-94e9GOpXJaLm9...](https://picasaweb.google.com/lh/photo/fWlV5aan-94e9GOpXJaLm9MTjNZETYmyPJy0liipFm0)

Sinewave has been generated with the command

    
    
       $ sox -n -t wav - synth 60 sine 1013.0  | aplay
    

on the raspberry pi.

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jimmcslim
Wonder if there's much of a chance of them cracking the extremely tight
synchronisation side of things for multi-room audio without the Sonos price
tag

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zokier
Doesn't PulseAudio do synced multiroom audio fairly easily?

[http://www.hackerposse.com/~rozzin/journal//whole-home-
pulse...](http://www.hackerposse.com/~rozzin/journal//whole-home-
pulseaudio.html)

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djfergus
Doesn't the RPI have a HDMI port? Can you pull digital audio from there? Ie
why the need for a USB dac?

Also, any chance of an arm port of some room correction dsp software?

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slowdown
I agree, the sound quality difference in an Audiophile setup will be
phenomenal between a USB source and a HDMI Source for the same lossless track
played. Thumbs up for HDMI.

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rdale
Most modern audiophile DACS have asynchronous USB inputs, and hardly any have
HDMI. I assume that is because the designers of the DACs all think USB works
better than HDMI for high quality 2 channel audio.

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c54
For some reason I misread the title and thought this was going to be an
article criticizing the new product

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GotAnyMegadeth
This looks great, has anyone tried it out yet?

