Friday, May 18, 2018

SoX on steroids -- Part II

As some people were asking me about sox performance on the RPI, I now did some testing.

I ran pretty much the same benchmarking tests on my PI3 as I did on the NUC.

Saturday, April 14, 2018


Anybody out there still ripping CDs?  Or is it just me. ;)

Last weekend I figured that a track was missing.

OK. Quick decision taken. ReRip that CD. 
Yep - I still keep my CDs in the attic. 

ReRipping "quickly" turned out into a major exercise. 

Tuesday, April 10, 2018

SoX on steroids

The quest for better performance will never end.

This time it's SoX - "The Swiss Army Knife for Soundprocessing"

We use it on e.g. Logitechmediaserver for samplerate conversions (SRC).
I use it for highest quality SRC to 352k8/384k for one of the DACs I'm running.

Perhaps there's something to gain in that area!?!?

Tuesday, February 6, 2018

Raspberry PI - The Audio Engine - Part 9 - USB HUB Control

We're still on the way to collect this or that crumb that's been left on the table.
This exercise is for those who followed my advise to use an external network dongle. 
And for those who still enjoy playing around with our little gadget. 

Today we're looking at how to control our USB devices. 
As you probably already know the RPI Ethernet port is part of the PI USB infrastructure - The PI comes with a combined Ethernet-USB chip. IMO the weakest and most annoying part of the PI! 

A fellow programmer - Yutaka from Japan - has written a nice little tool to control USB-Hubs. 
It has been written in 2006 and - guess what - it still works.

Monday, January 29, 2018

RaspBerry Pi - The Audio Engine - Part 8 - Network Dongle

Now I'll explain how to install an external ethernet dongle to our Audio Engine. 

First you should read the general article  I wrote some time ago. 
There I'm outlining why this exercise could be of interest for you. 
On PI Zeros that'd be a must-do exercise anyhow.

Saturday, January 27, 2018

RaspBerry PI - The Audio Engine - Part 7 - Realtime Kernel

A realtime kernel. The cream of the cake for a Linux based Audio Engine.

Did you know? Even the Squeezebox Touch was running a realtime-kernel almost
10 years ago!

A realtime kernel allows a much faster task switching thus much lower latency
compared to normal kernels. It's usually used in time-sensitive industrial 

From my experience this extremely low latency can make a difference for our purpose as well. 

Most of my mods you've seen so far follow the logic of reducing distractions to the audio stream. An rt-kernel very well adds to that logic. 

Thursday, January 25, 2018

RaspBerry PI - The Audio Engine - Part 6 - DSD Native

Part 6 of the series is dedicated to show how DSD-native playback can be achieved
on a RPI running piCorePlayer.  

DSD is quite a fashioned feature since a couple of years. It's a niche format though. However. There's a small community considering it a must-have-feature for audiophile audio playback systems. 

This exercise will show you how to get DSD working in your LMS/squeezelite environment.  

NOTE: This guide requires piCorePlayer 3.5

Saturday, January 20, 2018

RaspBerry Pi - The Audio Engine - Part 5 - Custom squeezelite

This is not the first post of this series. I strongly recommend to start @ Part1

Most of the project is done. If you're still not happy with the result!?!? Hmmh.

OK. We could do a little more. ;)


Perhaps you should wait  for another week trying this Measure. I strongly recommend to get used to the performance of your recently manipulated PcP setup first. 

The result of this exercise might not be that earth shattering as you'd expect it to be.

What can we still do !?!?

There are two big areas that still can be addressed. 

1. The squeezelite binary
2. The kernel

Friday, January 19, 2018

RaspBerry Pi - The Audio Engine - Part 4 - Advanced OS Tuning Measures

Nice to have you back @ Part 4 of the series.

By now you already should have a nicely running audio system based on the Raspberry PI3, a nice little HAT DAC and piCorePlayer as audio engine.

This part of the "RPI Audio Engine series" will cover some more modifications.

As with all tuning measures the ultimate goal is to make the system more efficient and to get rid of distractions. 

Everything until now, including some basic tweaks (HDMI off/WLAN off etc.), could be accomplished by using the WEB GUI.

Now it's time to switch to commandline.  Some might don't like it. Some might be afraid 
of it. You might reconsider.

Keep in mind. You can't do much wrong. If so. Just restore your backed-up SD-card, if anything has gone south.

I'll try to walk you through the journey. Tweak by Tweak.

Still. Remember. Everything you do you do at your own risk! Just to be clear about that.

This article is still Work-in-Progress!  Latest update: Jan-24-2018

Raspberry Pi - The Audio Engine - Part 2 - piCorePlayer settings

In Part 2 of this series I'd like to cover general settings for piCorePlayer that I'd recommend to look at.

Just to remind you. All settings assume a RPI3 as a base.

The main assumption still is that the PI runs as playback engine only. Meaning.
there's a seperate LMS server out there.

Wednesday, January 10, 2018

Raspberry Pi - The Audio Engine - Part 1 - Introduction

Since 2013 I'm using and working with the Raspberry Pi as audio streamer. 
I'm also contributing this or that to certain community projects.

Why Raspberry PI?

The Raspberry PI family is by far the most successful single-board-computer (SBC) out there.
Even though the PIs architecture and hardware can NOT be considered top notch (other SBC do (much) better at similar price levels), a PI can very well serve the purpose - to act as a rather serious audio transport. 
Not as an off-the-shelve installation, no, it requires some tweaking to get serious quality audio from that device. 

What makes a device like the RPI a success story is its wide market presence,
great and innovative SW (manufacturer+community) support and OEMs flooding the market with all kind of (quality) gadgets.
Many other SBC companies failed to succeed (beyond becoming a niche product), because they were not able comply to these factors - even providing a much better HW wouldn't help. Without being able to address the key area - proper and long-term SW support - these devices are pretty much worth nothing. 
Providing, evolving and maintaining quality SW is a continuous process over a long period in time.  That's what many manufactures underestimate! And that's why they usually fail.
And that's the main reason to go for a PI.

Thursday, October 12, 2017

Raspberry Pi - The Audio Engine - Part 3 - squeezelite and DAC settings

In Part 3 of this series I'd like to share some lines about the parameter settings of squeezelite.

squeezelite comes with numerous options that can change it's performance
as well as its functionality.

For this exercise I'll obviously be using  piCorePlayer once more. 

The LogitechMediaServer (LMS) setup I basically covered in the LMS configuration article.

Monday, August 28, 2017

LogitechMediaServer - Settings Guide

I consider the LogitechMediaServer (LMS) the best music server out there.

The LMS is the server part of a very powerful client/server audio streaming environment 
and requires a compatible streaming client, such as squeezelite

Here you might find some useful information and hints for a high performance setup.

Sunday, August 13, 2017

networking - RPI dongle your net

I'd like to share an - IMO - nice alternative network setup solution for the RPI3.

The solution will nicely add to or you might also call it  - enhance - earlier described networking solution.  

Tuesday, May 2, 2017

networking - my audio data highway

Years back I mentioned that the network and associated components do have quite an impact on your audio performance. 
Meanwhile this became common knowledge in - let's call it - audiophile minded circles. 

As usual, I prefer reasonably (priced) highest performance solutions. 
Usually a healthy mix of DIY efforts and commercial stuff gets me there. 

Today I'd like to introduce my "currently" preferred "audio" streaming network solution.

Tuesday, April 11, 2017

Raspberry PI - I2S-HATs @ 384k

Today I'd like to share how to introduce 352k8/384k upsampling 
by running LogitechMediaServer as server and squeezelite as a client.

This post, from a hardware perspective,  pretty much relates to my 

RPI I2S HAT DAC projects I've been running over at DIY-Audio.

Some DACs (TI PCM51xx family) have shown a slightly improved performance 

while running upsampled material. That's the main reason for writing all this up. 

Wednesday, April 23, 2014

Shoot the Trouble -- USB Audio Interfaces

With all the very interesting Raspberry Pis and other ARM devices around, Linux becomes more and more interesting for many people. Great audio transports can be build at 100$.
Not to forget. Tablet and Phones are mainly Androids and that is just another Linux, using the same soundlayer (Alsa) then all other Linuxes.

Manufacturers usually still do not commit to support Linux or Android properly.
Which is insane. The vast majority of mobile device out there are Androids.

However. Many devices work or partially work under Linux, because manufacturers comply to general USB Audio Standards (UAC1/UAC2). Meanwhile even Pro Audio companies like RME offer a "Class Compliant" mode for their newest generation of USB devices. (In the RME case they do officially focus on OSX though.)

Anyhow. Even though things are getting better, there are still plenty of  cases where you'll experience NO SOUND.

That doesn't necessarily mean that your device won't work under Linux.

This article outlines a little guideline for troubleshooting your USB audio interface under Linux.
It should give you certain hints what to look for.

However. Just to make it clear from the very beginning.

I won't support anybody, who got issues with his interface!!! Checkout Google or the community.

If you have comments for improving the article please let me know.

Tuesday, September 3, 2013

Hirez - Treasure Island - Part II

Today we cover HiRes (that covers DSD as well) vs. Redbook.

In the first blog about Hirez I covered the base HiRez material.

My conclusion was.:

Hirez material quite often seems to get resampled and remastered from unknown raw masters (formats).
There is usually nothing like a real "master" for sale out there.

Friday, January 25, 2013

Squeeze Me Lite

Latest update: 16-Aug-2017 


I'd like to introduce you to a my favorite audio application - a squeezebox streaming client - called squeezelite.

squeezelite is a versatile, highly efficient squeezebox emulator that runs on all PC platforms, micro computers, like a Raspberry Pi,  even on routers or NAS and also on the Squeezebox Touch .  Even commercial streamers make use of it.

It's opensource and it's free. And it's IMO been and still is a major enabler for streaming quality audio at home.  

Wednesday, October 10, 2012

The silent death...

Hi folks.

Do you sometimes have the feeling, of not feeling comfortable the way you handle and administrate your valuable music ( and video and image) collection?

You don't really know -- if all the audio file integrity is still given  (after all those years of moving files here and there) !?!?

Loundess war - finally over ???

Hi folks.

Anybody heard about EBU R128??

To be honest. I didn't until recencly.

I accidently stepped  over EBU R128 (EBU=European Broadcasting Union, R128=Recommendation 128) while looking for a better ReplayGain solution.

R128 finally defines a standard how loudness should be measured and applied in an acceptable way.

The standard was based on  ITU BS.1770 ( International Telecommunications Union) released in 2006.
ITU BS.1770  has been widely applied in the broadcasting scene.
EBU R128  significantly enhanced that standard by a function called gating (You'll learn more about it later on.)  The original ITU BS.1770 has been updated to ITU BS.1770-3 by now and includes the gating function as proposed by EBU R128.

Not only us - audio geeks - have a huge problem with low quality music and messup of audio data due to "Loudness War" - NO - broadcasters face the same challenge on a daily basis.  They can not sit down and change the volume on every piece they are broadcasting.

They have to normalize audio of much more media sources, such as speach, film, commercials, podcasts, audio asf. And by doing so, they're compressing and messing with  the audio data even further.

Wednesday, August 8, 2012

Ever heard about Full Digital Amps ??

(Sometimes they are also called PowerDACs or Direct Digital Amps or All Digital Amps btw.)

No !?!?

...the end of seperate  DAC + AMP decade might be near!!! ;)

For those of you who got tired to run after every new DAC and amp (I did), and
those who've read the 1000th review of another miracle  DAC (I did), or those
of you who got more confused then enlightened with the endless number
of DACs of choice out there (I did again), or those who look for a very small,
cost efficient and still great sounding system ... (Oh -- I'm talking about myself..)

Appendix 1: Market overview
Appendix 2: Patent
Appendix 3: DDX320 Modifications

Thursday, November 3, 2011

Touch Toolbox 3.0


Squeezebox Touch Toolbox

NO Longer Supported!!!!!!!!!!!!!!!!

Unfortunately I can't support my Touch Toolbox any longer.

Why? I don't have a working Squeezebox Touch anymore.

You'll be 100% on your own, if you continue to run the Toolbox.

If you keep running the Toolbox, you keep running it at your own risk - as always (see also Disclaimer on the right hand side).

As ususal, the Toolbox can be removed by a hardware reset (black button on the back of the Touch).

And remember: The Toolbox and EDO  shall not be installed at the same time!!

I'm still watching the Touch Toolbox Thread at
If you have any questions, meet me there. I won't answer private mails!

Thx to all of you, who tried and appreciated the Toolbox for quite a long period of time.

Note: If there is anybody out there, who would donate a SBT to me - I just need it for design, testing and support - I'd more than happy to continue this project.
I'd even consider to launch a TT4.0.



Wednesday, November 2, 2011

Touch Toolbox 3.0 - HW and Network

This blog is Part II of the Touch Toolbox blog.

Over here  I'll touch upon HW modifications, the network and server environment from a HW perspective.

I consider all this an integral part of your streaming solution. All this will also make a difference.

1. Power supply
2. Lan optimization
3. SPDIF data link
4. Onboard modifications
5. Server considerations

You really should have a look at it.  You'll also  find some easy to implement tweaks.

Thursday, May 19, 2011

Hires Audio - Treasure Island


Lets dig up some treasures. It's time to run another little study.

post over at Audio Asylum was referring to quite an interesting article about "fake" HiRes-Audio. files.

Within this article it's been stated that several HiRes audio downloads are potentially fakes.

What is HiRes? What is a HiRes fake?

The problem. The term HiRes is neither being protected, nor it clearly defines what can be expected.

The only thing that's defined is "HiRes Audio = audio data with greater than 44.1kHz samplerate"

Then. Why did HD-Tracks accept to replace potential fakes???  (for those complaining!)

Saturday, May 14, 2011

CD Extraction

With this article I'd like to tackle an issue, which always makes me feel odd
when thinking about it.

"CD Extraction"...

... do I really have it 100% under control ...

... after hundreds of rips and years of active involvement in Computer based audio !?!?!

I just read two articles in the latest issue of the german audio magazine  "Stereo". Stereo is one of the biggest, if not the biggest of its kind over here in Germany.
I do think they got quite a good reputation in the market. 

This month (05/11) Stereo stuck their heads into Computer CD-drives and extraction software to compare the results generated by the tools and drives.

The real interesting thing about it was the result of it.
The soundquality ranking of extraction results on different drives and different software in particular - got my full attention.
As a matter of fact according to Stereo, drives make a difference and tools make a difference on soundquality too - and they are not talking about subtle differences if you look at the SQ-ranking. There are drives going as low as 88% (SonyOptiArc DRX-S 77 U) and extractions tools as low as 94% (EAC!!!!) on the SQ ranking.

Guess what. EAC - was the worst of all.

Do I have a reason to question that Stereo article, assuming somewhat professional test-cases and setups (using Accurate Rip etc.) !?!?!


Thursday, April 21, 2011

Resampling - If you can't avoid it...

(Last update: Mar-28-2018)


I've been looking at the subject of audio data resampling now and than.
Somehow you can't avoid looking into it - for several reasons.
In my case some of my HW setups suggest to use resampled data 
to achieve a potentially better performance. 

While scanning the net I stepped over a lot of very fragmented and also incomplete 
Quite some stuff out there has a marketing flavor attached to it. 
And obviously you'll find numerous different opinions about the best way doing things.

With this post I'm trying to cover certain aspects, such as

* What is resampling or upsampling/downsampling or oversampling?
* Why resampling?

* Quality factors and quality targets
* What tools and applications 
* Conclusion

* Implementation on LogitechMediaServer
* Offline resampling
* Sox installation/update and compilation (script)

Let's get started.

Annex 1: Script to compile latest Sox for Debian/Ubuntu systems
Annex 2: Sox LMS upgrade on Debian/Ubuntu systems

Thursday, November 11, 2010

soundcheck on Hifi-Music-World 2010 presenting a Touch based solution

Last weekend I had been invited to present a streaming solution based around
my fully tweaked Touch to the public on the biggest german DIY fair (Hifi-Music-World 2010) in Stuttgart.

Silvercore (a manufacturer of  real great sounding tube-amps, transformers, pre-amps and now  also a DAC  and Bastanis  , who produces my all-time f
avorite speakers, were teaming up for a gig.

Surprisingly I was invited to present my streaming solution based on a Squeezebox Touch, feeding their system.

Me on the "other" side!?!? Feeding such equipment on a show.  Brave guys!

Hmmh. I thought - why not I know what I'm doing. Lets give it a try.

Wednesday, August 11, 2010

(Digital) Volume Control


There are lots of discussions ongoing if one should go or not go for digital volume control.

This is the way I see it:

It'll depend how well it performs.

First of all it doesn't cost you anything, it is easy to handle, makes certain quite expensive audio HW obsolete, resolves quite some analog volume control associated problems and it can sound damn good.

Wednesday, June 16, 2010

Computerized Audio


The "audiophile" audio world is heading towards computerized audio.

Though there'll be high hurdles to cross to evolve into the computerized audio world for the
wider "audiophile" community. 

To accomplish and maintain an audiophile setup using a PC, a network and an audio interface must be considered a pretty complex undertaking.

You need to have a pretty good understanding of computers and networks and associated audio devices and of course the software driving all that.

You need to continuously follow up on these. The entire setup  needs to be thoroughly planed,  selected and integrated to meet the high demands of the typically very demanding audiophile person.

Transferring your music data to the PC and maintaining your database
must be considered a major challenge too.

It is getting better nowadays, with automatic grabbing boxes and professional grabbing
services. Still getting a consistent database in place means a lot of extra manual extra work.

All this, just to replace a single CD player? Does all this effort makes sense?  

Honestly, I am really not sure.