Ich habe sämtliche Verträge mit der Lautsprechermanufaktur Heyder (LMH) gekündigt und die Nutzung meiner Erfindungen und DRBA Horn Designs verboten.
Die LMH hat trotz Aufforderung weder die Prototypen der Hörner herausgegeben, noch hat sie in sonstiger Weise mit mir Kontakt aufgenommen.
Ich bitte um Verständnis, dass zu diesem Zeitpunkt keine weiteren Angaben gemacht werden.
Hi,
for more frequent posts and also other non-horn related stuff, I have created an Instagram account: @drba.sphericalhorns
https://www.instagram.com/drba.sphericalhorns/profilecard/?igsh=NndvdG5qN2JyaTlk
Writing technical articles is very time-consuming, and it requires a different level of care and accuracy. Instagram seems to me to be very suitable for occasional brief information and reports. 
I’ve already mentioned that my great passion is analogue music playback and records in particular. If you take a closer look, you will realise that the signal has to be filtered before it can be cut into a master lath. Low frequencies are attenuated and high frequencies are boosted in order to achieve roughly equal levels. This is usually referred to as an inverse RIAA filter. During playback, a corresponding reciprocal RIAA filter is applied in order to achieve a straight frequency response. The following article was written back in 2018, when Sowter helped me build an LCR-RIAA filter with twice the impedance of the usual 600 Ohm modules. At that time, Sowter still offered a custom design service.
The development process, theoretical principles and practical tips were summarized in a white paper and Brian Sowter published the white paper on his web site:
https://www.sowter.co.uk/pdf/LCR-RIAA%20Ahlswede.pdf
I didn’t have my own website back then. I would therefore like to publish the topic again in this article.