The new Raspberry Pi 4B has been received
with open arms by the computer press.
It performs like an entry level desktop computer,.
So audio lovers want to know how much better
it is for music reproduction.
The processor on 
the Raspberry Pi 4B now is a quad core ARM
Cortex A72 CPU running at 1.5 GHz.
Although it runs at only a slightly higher
clock frequency, it has three times the performance
of the Raspberry Pi 3B+.
Add to that the LPDDR4-RAM in stead of the
LPDDR2 RAM found in earlier models and you’ll
understand why it does number crunching at
a far higher speed.
There also is an option now to boot from USB
and since the Raspberry Pi 4B now also has
USB 3.0, further speed improvements can be
made.
For video lovers: The Raspberry Pi 4B now
supports 4k video over two micro HDMI ports.
There are three versions of the 4B, the only
difference being the amount of RAM.
That can vary from 1 to 4 GB.
Another good thing about the 4B is the gigabit
network adaptor.
Previous models were limited to 100 Mbit ethernet
that had to share throughput with USB.
A short note on the power supply: don’t
use smart power supplies, like the ones that
come with Apple Macbooks.
Due to a design flaw in the Pi, only dumb
power supplies will work.
There clearly is a hefty performance improvement
on all sides.
The question is what that will do to audio.
Let me first make clear that using any Raspberry
Pi for audio without the addition of a special
sound card will work but the analog output
sounds horrible while using the USB to feed
a USB DAC also leads to very poor sound quality
due to the polluted USB signal.
You should use a sound card in the shape of
a HAT board.
I have tested the Raspberry Pi 4B agains the
Pi 3B+ using an Allo Boss 1.2 DAC board and
the Allo DigiOne Signature SPDIF board.
The Boss was powered using the sBooster BOTW
P&P ECO.
In it’s turn the Boss sent the power to
the Pi.
The DigiOne Signature was used with two power
supplies: the same sBooster plus a cheap switching
mode power supply.
Both were connected to the DigiOne’s specific
power inputs.
For reviews of the Boss and the DigiOne Signature
see the links below this video in YouTube.
I started with installing RopieeeXL, the new
version of Ropieee that not only makes the
Pi a Roon Endpoint, it also makes it an Airplay
and DLNA renderer.
A short review will follow suit.
I also installed Volumio 2 to test a more
processor intense program.
More on both programs in their reviews, links
below this video in YouTube.
In general the Raspberry Pi 4B sounds somewhat
less open, has slightly less sibilance control
while the stereo image was narrower.
Only when playing the Boss DAC with Volumio
the low end was slightly defined but everything
else stays the same.
You might wonder why a better computer produces
a lower sound quality.
I have no means of measuring this but in general
faster processors generate more electric and
electromagnetic noise for a number of reasons.
The HAT boards are mounted on the Pi at only
2.5 cm distance.
The Allo Boss does some filtering, the DigiOne
Signature has fully galvanic separation and
even then there is influence from the PI to
the HAT board.
It is to be expected that simpler DAC board
even suffer more.
I have not tested this, though.
Now, let me be somewhat more precise about
the sound penalty for using the Raspberry
Pi 4.
If you own a stereo like my sub € 1000 setup
3, I wouldn’t loose any sleep over the difference
between the Pi3B+ and Pi4B.
If your stereo is more like my € 4000 setup
2 or better, I would definitely go for the
Pi 3B+ for as long as it’s available.
I am in the privileged position to be able
to look inside very good sounding dedicated
streamers and they almost always have relatively
lightweight CPU’s.
And I have often hear designers saying that
USB2 is better for DAC’s than USB3.
It’s not really strange, normal 44.1 kHz
16 bit audio has a data throughput of 1.41
Mbit per second and even 192 kHz 24 bit signals
only do 8.46 Mbit/s.
USB 2 has a data signalling rate of 480 Mbit/s,
which is about 57 times as high.
Even if the transport overhead is subtracted
there is ample bandwidth for two channel audio.
The same goes for Ethernet.
A 100 Mbit network is more than fast enough
for audio, provided the network is not used
for other high bandwidth activities like watching
video and backing up large volumes while listening
to audio.
If there is, you might consider separating
your audio network from the rest.
A simple way is to connect your audio related
equipment to one switch and patch that to
the rest of the network.
Connecting a hard disk directly to your audio
gear, like a USB drive directly to the Raspberry
Pi is no bad idea either.
The KISS principle is still valid:Keep It
Simple Stupid.
That’s it for this week.
There will be another video next Friday, as
always at 5 PM central European time.
If you don’t want to miss that, subscribe
to this channel or follow me on the social
media so you’ll be warned when new videos
are out.
If you liked this video, give it a thumbs
up.
Many thanks to all that support this channel
financially, it keeps me independent and thus
trustworthy.
If you also feel like supporting my work,
the links are in the comments below this video
on Youtube.
I am Hans Beekhuyzen, thank you for watching
and see you in the next show or on theHBproject.com.
And whatever you do, enjoy the music.
