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Capital Audiofest

We are pleased with the very good rating of stereophile about our custom & subway at the Capital Audiofest (Thx to

“An assembled TU-8600 sounded amazing driving a pair of AER twin-paper-cone, full-range drivers in shallow, cleverly made Plexiglas horns (3900 Euros/pair for the drivers, 3200 Euros/pair for the enclosures). Judging from the smooth, wide-range, and altogether non-problematic sound I heard from those 106dB-sensitive, easy-to-drive (16 ohm) German-made loudspeakers, I can only conclude that the best Lowther-like drivers are no longer made by Lowther—far from it.”


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The Excenter

The extraordinary design of the Excenter successfully combines the beneficial acoustic properties of spherical horns, open baffles and point sources in a single speaker. The horn is powered by a full-range speaker; a subwoofer takes over only under one hundred hertz. This low crossover frequency has great advantages and was one of the aims in developing the big horn. It is important to note that the human voice in its transmission range, which reaches down to eighty-five hertz in its deepest tones, is transmitted without breakage by just one chassis.

Go to Excenter

Customer Gallery

In the category “customer gallery” we show the “living rooms” of our customers. Here an exclusive system in Russia. The chain of the absolute top class components  is completed by our BD4 with ecentric horn. Our valued customer is excited and sent us a self-measured frequency response. Our Excenterhorn with BD4 driver delivers a nearly linear frequency response of 80 Hz – 60 kHz.

>History of the system over approx. 25 years

Customers about AER

Some of our customers have been experiencing AER products for decades.

Mr. Werner Schäl summarized his satisfaction in a forum post:

I am using the AER BD3 by Filip Keller for 4 years now. I’ve never used a speaker for such a long period of time. The reason is simple: I am always pleased to listen to these speakers. My electronic gear changes quite often for my system is improving by the time. The loudspeakers are able to reproduce anything that is fed to them. At the beginning I had some problems with “crisp” highs, but this was was definitely caused by wrong electronics and cables for the use of these loudspeakers.
I’ve been compulsively into this hobby for 30 years now. Of course, I will never be able to enjoy all the products available, but almost everything I’ve heard yet (at high-end trade fairs, in private, at showrooms) I estimated far worse compared to my listening experience at home. And there, the Keller-drivers have the hugest part in it.

Of course this is not yet perfect, but expanding and testing makes the whole hobby so interesting to me. Also, I’ve already heard a Visaton B200 in different cases, but I think it didn’t sound as fresh and open and clean in the heights as the BD3 chassis.

When hifi-driven people listen to these speakers, so far everyone has been enthusiastic about them. Of course, they are expensive, but as a reward one finds a lot of work, a lot of development work and experience in the chassis. If I calculate what I might have spent on speakers in the last few years, my choice was reasonably priced after all.”


We would like to thank Mr. Werner Schäl for his kind contribution.

Customer Feedback BD3 Driver

We are constantly improving our Loudspeakers and Chassis.
Here is feedback from a satisfied customer:

Dear Mr. Filip Keller,

Today I  recieved the AER-BD3 Chassis to upgrade my AER-BD1.
A quick reconstruction and then the first test-listening. I expected the new Chassis to sound better, but I hardly imagined such a great leap forwards in performance. I was actually happy with my old Chassis, but the new ones are better in every respect…even though they’re not yet „worn-in“. Many thanks!…also for the informative discussions we had which lead me to upgrade with the BD3.

Hoping to meet you soon
Friendly greetings

>To the BD Chassis Page