Backes & Muller BM 35

Her novel cylinder wave radiators depicts music as accurately as no other speaker. Technically is the active speaker BM 35 a revolution – even?

  1. Backes & Muller BM 35
  2. Data sheet

For the purists with LP Leno and tube amp the BM 35 speakers by Backes & Muller must seem like a shock: with digital active crossover, for chassis calculated by the Fraunhofer Institute and connectors for a laptop.

B & M Chief developer Johannes Siegler, very successful in the Studio are strange nostalgic impulses. But can clean up a single box with the stubborn prejudices against the active such as digital technology? She can. Depending on the music and listeners it needs for only a few minutes: with a spatial figure, as the high end world has never heard.

In the middle of high-frequency

While many manufacturers of high end now access to the shelves of same chassis, the Central transducer of BM 35 is so unusual that even experts immediately can guess how it works. It is not a Ribbon, but a line of spotlights with dynamic drive. From 800 to 20,000 hertz he supposed to narrow the radiation in the height – reflections on floor and ceiling in the room be reduced so immensely, the location is better.

Many other technical principles also promise this bundling – in contrast to ribbons and d ‘ D’appolito arrangement this behavior through but keeps the B & M spotlight at all pitches. This is ensured by the wooden sound leadership, which also prevents edge reflections. Front four Cone chassis, sit over each other similar to a sound source mounted, the two outer hide gently — so even mid tones are bundled similar to clear, but evenly. It will be even more complex at the back of the BM 35: The two 25-centimeter, sub bass are mounted at a great distance to each other. This has the advantage that they stimulate the vertical space resonance far less than a single woofer.

Total digital

The waiver of a bass reflex resonator contributes to a dry and balanced bass experience, as well as the sensor control, in which the electronics continuously adjusts the position of the membrane to the music signal and to prevent distortion, compression, and vibration to. Centrally there is an enclosed Chamber for the electronics, the amplifiers are built in classic A/B technology.

Digital, however, is the complete turnout electronics: A digital signal processor (DSP) with 32-bit resolution distributes the signals to the output stages not only ensures a straight response and optimized also the phase response: all frequencies are emitted at the same time, even the linearity plays time correctly. Calibration each copy via microphone and laptop guarantees absolute equality of pair – important for a good illustration.

Even without a PC, the owner can customize the three parametric filters, as well as an additional location equalization with jog. It was also necessary in the case of AUDIO listening area, in which a space fashion caused cancellations in the bass. The new no longer has the polarizing waist of older B & Ms – it appears despite the height of 1.70 m slim and elegant. Side panel and sound management are made of solid wood, the baffle for the midrange speakers, however, consists of polished stone. Solid workmanship is evident inside: thick, BA.33 MDF walls and separate housing for low – and midrange driver, which should be immune due to oblique construction against standing waves.

Music… nothing

As a candidate for the reference class the BM 35 with the Focal Grand utopia got tough competition – and purposed with Berlioz’s “Te Deum” (AUDIO Super listening course CD 5) complex food. Where the focal only outlined the positions of 400 musicians, the Backes was each to its proper place: incredible! It allowed a hearing by the music, a tracking of each individual voice even on less favourable seating. Mr Lothar Brandt attested to her “picture sharpness a reading glasses” – but with the width of a panoramic painting. The focal countered somewhat overemphatic articulation with a smoother, fuller tonal vocal reproduction.

The once popular test track “Tricycle” of flim & the BB, the deep bass with unknown precision from the regulated woofers surged’s, the focal noticeably softened this bass beats. The BM 35 detailed honesty can be but also sobering. Weaknesses of the recording technology exposes them mercilessly.

It was approaching the moment of truth, the grading. The focal had to admit defeat when it comes to illustration and ESS, in the bass was powerful, less accurate for it. Despite their victory is good for you as a working reference but only very conditionally for the editorial – how should you test with her a power amplifier? The appropriate B & M-CD Player even preamp and transformer eliminates thanks to consistent digital connection. Also high tech can be very consistent – and wonderful sound.


The BM 35 by Backes & Muller could be a new era in the history of the high end establish with their technology – the Digital active-high-end. Ultimately it is their sound but, more specifically: your impressive set design, this hitherto unmatched detailed and almost walkable spatial representation of the music that distinguishes it from all other speakers. This works perfectly without even damped room and a precise list. It’s great that such a revolution is finally once again comes from Germany!

Backes & Müller BM35

Manufacturer Backes & Muller
Price €56000.00
Rating 107.0 points
Test procedure 1.0




Technical data and test results

General data
Dimensions (W x H x D) 33.0 x 173.0 x 48,0 cm
Weight 150.0
Surfaces Solid wood and stone front
Color any wood
Technical characteristics
Bass principle Way closed
Number of ways 3 1 / 2
Working principle of full Active
XLR connectors
Space adaptation Digital location correction, equalizer
Surround complementary.
Laboratory characteristics
Maximum volume upper value
lower cut-off frequency (-3dB)
Lower cut-off frequency (-6 dB)
Nominal impedance (audio)
Ultimately precise, neutral and accurate mapping.
Voices bring something, deep bass could be more important.
Bass quality 100
Bass depth (bass Foundation) 100
Attention to detail (precision) 115
Dynamic 110
Maximum level (vitality) 100
Neutrality 105
Imaging 110
Spatial (airiness) 110
Processing outstanding
Sound judgment outstanding 107
tested in issue: 2 / 07