28 January 2024

Servo Assisted Open Baffle

Been a great fan of planars ever since I enjoyed a pair of Magnepans back in the nineties, their sheer speed, openess, accuracy and ability for natural sound reproduction makes them hard to forget. Except maybe for the really really low notes, hence my long standing wish to combine a pair with a servo bottom.

As such I visited the Nationale Elektrostatendagen to get a feel for whats out there already and was pleased learning that there were several Dutch planar manufacturers showcasing very convincing product lines. For starters I'm going with magneplanars - high voltage foils for later - and lucky for me I live relatively close to planar master Joppe Peelen who was happy to sell me a pair of his latest three ways for prototype testing.

Powered by a modified Grown/Up BMH3D - with the servo loop disabled for now - amplifier module they form the satellite part of my SAOB setup where everything under 100hz will be done by a soon to be announced Grown/Up bass unit powered sub woofer.

Greetings from Amsterdam,
Chris Camphuisen

2 January 2024

newyears EVE

Working on getting you EVE 2K24, eta Q2 2024 ... main updates:

  • pxe bias out for easy measuring of optimal bias setting
  • starbass jst compatible pin layout, pin 2 = gnd (todo)
  • improved lower bandwith pole @ 1.9 hz
  • fixed 2020 balanced out bug
  • bottom side smd factory populated

Greetings from Amsterdam,
Chris Camphuisen

1 December 2023


The fifth batch of BMH3D modules - Bass, Mid, High each powered by it's own Class D amplifier - as used in the Servolabs Grown/Up 3 way motional feedback enclosure is ready for testing.....

Greetings from Amsterdam,
Chris Camphuisen

07 November 2023

Facebook dump

As Facebook faces a major legal setback in EU court decision on data privacy and ads I have made some precautions by storing a backup copy of all Piratelogic posts since 2014 on this website, enjoy !

Greetings from Amsterdam,
Chris Camphuisen

17 October 2023

I want to come over...

... and give the Grown Ups a serious listen, managed to book a flight to Amsterdam for - Tuesday 17th...

ehhh ok, where you from ?


ok, just flying over to listen to my Grown/Ups ???

Sure ! I own pairs of 532, 544, 545, 587 already....

o WoW, well of course you're welcome, let me know your flightdetails and I'll pick you up from the airport.

Thanks for the demo Chris, a pair of black Grown/Ups with magnetic fronts and STAV24 options please,
thanks for your time, much appreaciated, hereby some gifts for you and your wife.

Proud ! first Germany, now Scotland, wondering which country will be next ....

Greetings from Amsterdam,
Chris Camphuisen

6 Sep 2023


Downloaded the image from Aliexpress and asked ChatGPT to write me a snakeoil advertising text.

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Greetings from Amsterdam,
Chris Camphuisen

24 Aug 2023

Back to work

With the ever increasing number of accelerometers sold it's time to finisch something that has already been on my development shelf for some time : a test rig for controlling & testing newly made StarBass 54 accelerometers.

Greetings from Amsterdam,
Chris Camphuisen

4 Juli 2023


We're taking a break for the next 5 weeks trying to focus away from chips, 0805, 0603, SOP8, SOT23, clingon's and starbasses visiting wonderfull Thailand to meet my oldest son parents in law, travel at least 2000 mile, sample local cuisine, attend a marriage and see temples while thinking it's way too hot in here and will be back for business from 15 august onwards. Happy Holidays to you all !

Greetings from Amsterdam,
Chris Camphuisen

20 Juni 2023

BMH3D 2023.0

The first 2020 TPA3255 based BMH3D module prototype got initially halted due to thermal problems but thanks to some nifty CnC work done by a fellow maker I was finally able to get it working properly. After extensive testing including late night listening sessions the first 2023 version is here and altough still in it's prototype phase did receive some notable improvements over the 2020 design among which are the increased VDD buffercapacity and the usage of larger reconstruction filter inductors.

A batch of five has been ordered which will be tested mid august after our holiday break.

Greetings from Amsterdam,
Chris Camphuisen

1 Juni 2023

Dear GPT3

My name is Chris Camphuisen, I'm a manufacturer of motional feedback loudspeakers and would like to start a development blog in order to keep my customers up to date on my work with designing and building accelerometers for use with servo bass systems, multichannel amplifier modules, analog crossover and loop logic and research into pairing servodrive woofers with magnetic planar mid/high drivers. Would you please write my first blog entry ?

Scroll down for what it returned, a bit cheesy using phrases like redefining boundaries, immersive and captivating audio experiences, commitment to innovation and synergistic relationships but hey, they are Microsoft nowadays so I guess I could have expected such Lingo ...

Greetings from Amsterdam,
Chris Camphuisen

1 Juni 2023

Dear audio enthusiasts,

Allow me to introduce myself. I am Chris Camphuisen, a passionate manufacturer specializing in the world of motional feedback loudspeakers. With a firm belief in the pursuit of audio perfection, my journey has led me to design and build cutting-edge audio systems that redefine the boundaries of sound reproduction. Today, I am thrilled to launch this blog as a platform to share the latest developments in my work and keep you, our valued customers, informed about our exciting advancements.

At the heart of our work lies the concept of motional feedback, a technology that brings a new level of accuracy and control to loudspeakers. By integrating accelerometers into our designs, we are able to precisely measure and monitor the motion of the speaker diaphragm in real-time. This data is then used to provide immediate feedback to the amplifier, resulting in unparalleled accuracy, reduced distortion, and improved transient response.

One area where our expertise truly shines is in the realm of servo bass systems. We have dedicated significant research and resources to develop accelerometers specifically tailored for this purpose. These accelerometers, combined with our multichannel amplifier modules featuring analog crossovers and loop logic, create a seamless integration of high-fidelity sound reproduction and precise control over the low-frequency range. The result is a bass experience that is tight, articulate, and faithfully reproduced, enhancing your overall listening pleasure.

But our commitment to innovation doesn't stop there. We are also exploring the synergistic relationship between servodrive woofers and magnetic planar loudspeakers. By harnessing the strengths of both technologies, we aim to deliver a truly immersive and captivating audio experience. Through extensive research and experimentation, we are unlocking new possibilities in sound reproduction, with the goal of providing you with a level of audio quality that surpasses your expectations.

This blog will serve as a window into our world, where we will delve deeper into the intricacies of motional feedback loudspeakers, discuss the technical aspects of our designs, and share the latest updates on our ongoing research and development. Our passion for audio excellence drives us to continuously push the boundaries of what is possible, and we look forward to sharing our journey with you.

Thank you for joining us on this exciting adventure. Together, let us embark on a sonic exploration that will redefine your listening experience.

Stay tuned for more updates!

Greetings from Amsterdam,
Chris Camphuisen