Silence your acoustic piano. Practice whenever you want

Piano, Classical Music, Piano Player, Pianist, Man

I have a Pfeiffer piano, roughly 40 years old. Pfeiffer is a premium brand, using in my case premium hammers, and using a Renner mechanic. They provide their mechanics to the most reknowned brand, e.g. in a Steinway & Sons Model D (Hamburg) you will find one. So naturally, I was quite nervous on touching my piano.

When I asked my local piano builder, while he was tuning my piano, if he could recommend a digital piano (e.g. Yamaha P-125 or so), he instead offered up the idea to retrofit my piano to be a silent piano with a retro-fit system.

I decided to buy the adsilent system, which supposedly is one of the best of the available systems, and it can export the sound as midi via USB or Bluetooth, has line-out, headphone jack, metronome, different sounds, can record your play and play it and all that fancy stuff you can do with an app. Hooking the system up to GarageBand, Pianoteq or any DAW/Sampling solution should be totally possible, I haven’t tried it though. Moreover, when I contacted their sales people, the founder of the company kindly responded to my questions in detail. Great service!

So, when the time came, the piano builder took my piano apart, put an optical sensor bar below the keyboard, reflectors on each key, added a stop bar and reconfigured the release. Surprise: even though in forums people complain about the release being too far away from the strings and thus the key action and ability to play with quick repetitions or pianissimo is getting worse, this hasn’t been the case for me.

My release is in average at 2,5mm, previously it was at about 1-2mm. This makes me very happy, because playing feels the same for me when in acoustic mode and additionally the digital playing is awesome, providing some high quality samples of pianos, even though there is the tinies bit of a feeling that is different – maybe it would go away with a foam covered stop bar instead of a felt covered one, but I haven’t used the available premium bar yet. Still, it feels 99% like before or playing acoustic.

So if you have an acoustic piano and consider buying a digital one, maybe retrofitting your acoustic one is an option. It all is dependent of having the right person doing the retrofit though – you need an expert in piano building and somebody who is regulating the release and dampening of your instrument with passion – in my case it took the piano builder and his son some hours to install the silent system.

Next step is going to be hooking it all up with a computer, and then with a Raspberry Pi 4 to test out Pianoteq 7.1 for ARM to see, if it can maybe even improve on the factory-installed sounds. They are actually quite good, but according to the web, Pianoteq seems currently be the leader in “physical modelling” a piano sound, which – at least in the long run – should be superior to a recorded/sampled instrument as it is trying to emulate the physical swinging and proliferation of sound as it would be happening in a real piano instead of playing recordings.

Help to automatically select NordVPN server on your router

Just a quick service post and reminder to myself: To update the NordVPN server to the currently least loaded one for a given country, I’ve written some scripts that can be used when restarting the VPN connection or periodically to keep the OpenVPN configuration always updated.

Basically, those scripts download a template config from NordVPN and afterwards uses their website backend API to determine the currently least used server using curl and jq.

You can find the scripts in my GitHub repository.

Dive into Spring Cloud Data Flow on Kubernetes with Minikube for Mac OS

So you want to run Spring Cloud Data Flow on Kubernetes. Let’s start. First you must install Kubernetes and Helm. As a Kubernetes distribution, I used minikube and installed it using homebrew

brew install minikube helm

For Spring Cloud Data Flow, I use the Bitnami helm charts here. To deploy Spring Cloud Data Flow, you need to execute the following two commands, which will install a rabbitmq pod, a MariaDB pod, Spring Cloud Data Flow Server and Skipper and the corresponding services for the pods. You may want to start minikube with more CPUs and Memory as we are deploying quite a few artefacts, so the start command gets some more parameters:

minikube start –cpus=4 –memory=8192
helm repo add bitnami
helm install scdf bitnami/spring-cloud-dataflow

You can get data flow dashboard with the following command:

export SERVICE_PORT=$(kubectl get –namespace default -o jsonpath=”{.spec.ports[0].port}” services scdf-spring-cloud-dataflow-server)
kubectl port-forward –namespace default svc/scdf-spring-cloud-dataflow-server ${SERVICE_PORT}:${SERVICE_PORT} &
open “${SERVICE_PORT}/dashboard”

That’s it.

Indian Butter Chicken

If you have been searching for a recipe of original tasting butter chicken, the like you get at restaurants in Mumbai (like Saffran in Lower Parel), search no further: I found an original tasting recipe on YouTube that is just delicious. You don’t need that much sugar though, instead of 4 tablespoons of sugar, I only use one (and yes, I do like sugar).

Improve VPN performance on ODROID N2

I like to secure my home network with a VPN, so I have used single board computers for years for that. I started with the Raspberry PI 1, upgraded to BananaPi 1, then upgraded to an ODROID C2, tried out the new Raspberry PI 3, before ending up with my current ODROID N2. I upgraded frequently, as running encryption on these small computers maxes out their CPU capability with ease, and OpenVPN only uses 1 CPU Core, so having a multi-core CPU does not help a lot in this use case. Also, even though my ODROID N2 has hardware accelerated AES encryption, unfortunately, the SHA512 hash algorithm used by my VPN provider is not hardware accelerated. In addition to the VPN, I use the ODROID as PiHole to filter ads and trackers on a DNS network level and also as a network backup server that emulates an Apple Time Capsule.

In this post I talk about how I was able to get better VPN performance.

It has happened several times to me that openvpn was slow, and not delivering more then 40 MBit/s on the connection. Instead I saw a rather high cpu/interrupt load for ksoftirqd/0. After a lot of searching, I figured out that it was using one of the 2 “little” ARM A53 cores instead of the faster ARM A73 cores. On the ODROID N2 the little cores are cores 0-1, the big cores are 2-5 (for some details on the processor architecture, see

The solution? Setting the CPU affinity, meaning the preference where the openvpn process runs, to the faster CPU cores by changing the startup script (/etc/init.d/openvpn) to startup the openvpn process using taskset:

DAEMON="taskset --cpu-list 2-5 /usr/sbin/openvpn"

Depending on your system, you may also want to change the Systemd service to execute the openvpn process with taskset, too. You can prepend the taskset command from above in the service definition file in:

/lib/systemd/system/[email protected]

and then run:

systemctl daemon-reload
systemctl restart openvpn

After a short speedtest, I now reach more than 300 MBit/s with OpenVPN running with AES-256-GCM and SHA-512 encryption.