The precursor of ICE502 von Backes & Muller can transmit digital signals unadulterated in an active speaker. We have tested it along with the BM line 15.
If there were a prize for understatement in the high-end segment, the ICE502 by Backes & Muller would be a hot contender for the title. Not only that they their front panel and display behind a Matt acrylic glass pane hides and extremely unimpressive comes also in size and weight for a high end device, their functional diversity you would not even guess due to lack of controls in my wildest dreams.
B & M ICE502: Connections
The paper form is a Stereo preamplifier. And in fact can choose and select the volume with the volume knob – the only control on the front page – the owner between eight input sources. The sheer number of potential sources may impress already, but the diversity is important for everyday music listeners: in addition to two analog inputs and two classic S/PDIF RCA- and the 502 also offers a XLR input labeled optical connections AES / EBU. This picks up signals from professional digital sources like network players, CD drives, mixers, or DAT players. Course in all common resolutions, also 192/24, for the lovers of hi res downloads one absolutely necessary feature.
As high resolution, you can transfer the data directly from your PC or Mac to the B & M. For this purpose the eighth input the type of USB, which then is logged into the computer as a sound card or audio device, which is done usually automatically. The ICE is not just a precursor, but at the same time D/A converter. Where are doing hard, to refer to them as such has it in addition to the two pairs of analog outputs (RCA and XLR) but still a couple of digital outputs, also in the balanced XLR.
B & M BM line 15: Construction
Owners of Active speakers with digital input will choose the digital connection option, an adapter on RCA is here no problem, provided there is no AES/EBU input available. The signal always includes both channels, so must be selectable in the box be if it transmits the left or right channel.
It is preset in the BM Line 15. The three way active speaker represents something of a link between the two series at B & M, she owns but already the full digital switch electronics and all the expensive BM25 and BM35, Equalizer features sets of sound conversion but on conventional dynamic chassis.
B & M BM line 15
The midrange tweeter is clay split between three, with the arrangement shall cause so midrange, tweeter, midrange – according to the specifications of D’ D’appolito – a location of all sound events on vertical sound movement. The B & M pioneer Johannes Siegler speaks of a “virtual coax”, so approaching a point sound source, which can be reached only by adhering to the D ‘ D’appolito rules with a low crossover frequency (1500 Hz). So that the tweeter is neither distorted nor takes damage, a particularly effective and yet phase linear Digital FIR crossover is used here.
The two 12 cm measuring midrange driver with carbon fiber cone are installed behind a slot, which joins harmoniously the sound leadership of the tweeter, and to perpetuate the horizontal dispersion of all three drivers. The sound wall made of artificial stone is not this plan, but like a big sound management slightly towards the sides rounded – limited the angle on a sensible commercial area of about +-60 degrees and also effectively reduces the occurrence of edge reflections. A sensor control of the medium or even tweeters is not used with intention; the digital crossover can linearize the movement of drivers without measuring perfectly, as well as optimize the timing.
The two Bass drivers with 20 cm diameter play up to 400 Hz up and have an inductive acceleration transducer behind their carbon fiber cone. So the electronics can possible deviations from the music signal – whether correct compression or vibration – actively and without noticeable delay on the amplifier. Is driven any of the three branches of the drivers of its own, in the case of the bass 180 Watt sine wave high Power MOSFET amplifier.
The use of classic analog power amplifier technology and State of the art digital filter is no contradiction for Siegler. On the contrary: only the modern FIR turnout allow high side slopes and best equalization options, without distorting the signals in the time – and phase. On the other hand he speaks to a best possible control of the chassis the MOSFET power amplifiers, which can be reached only with direct connection to them. The amplifiers are not entirely conventional: they include an analog volume control, which can be also controlled remotely from prepress and thus yields the best possible signal to noise.
B & M ICE502 & BM line 15: hearing test
In the age of surround and network technology of inclined HiFi testers over a component, forward the without any installation and setup process plays just from plugging in. This pleasant genus that belongs definitely ICE: Linn Akurate DS network players provided the data of the digital “reference recordings” in the unusual resolution 176/24 – no problem for the ICE, which processed the data stream from the first second and gave volume-regulated on the BM Line 15. Richard Strauss’s “Dance of the seven veils” tinged with great unity and coherence, the dynamic energy built up slowly and completely of course that, the Orchestra sounded homogeneously and full bodied.
Who has associations with cool, technical sound when the keyword “fully digital system”, let by the B & M system, a better instruct: already bribed with conventional connection option via a controlled AES/EBU Signal chain at the analog played “calling all stations” (from Genesis) with a cosy warmth and her outstanding musical sense of timing. The sometimes somewhat casual bass portions of the recording came her full-bodied but never spongy. Due to the incredible uniformity they felt, here to listen to a wide strips or a purist two-way box instead of a so complex chain more.
In the final chorus of Beethoven’s 9th Symphony (Haitink, LSO) allowed the BM15 then dynamics on resolution demonstrate. And how she did it! Singers and instrumentalists completed them with instinctive accuracy and left as the musical event itself when leaning back easily track the listener. Her power kept it to the drum beats and the massed tutti first for themselves, without cluttering the quiet passages such as the usage of the baritone. Their spatial representation was extremely accurate, marked tone-color of a certain coziness, staggered but not excessively far in depth, but always relatively straightforward.
Also with the beautiful, new world of music from the PC, the ICE502 harmonized beautifully: the connection of USB input with the PC after a short confirmation of the appropriate driver managed easily, and Carlos of Santana’s “you are my child” (featuring seal) grooved on the BM15 with perfect sense of rhythm and a Foundation playing tired to the point go, it was a real pleasure. The full digital B & M combination is concepts, the future belongs to the one of the high-end apparently future-proof – and no doubt.
Connections and volume control
Digital signals in PCM format (Pulse Code Modulation) are generally specified sampling rate, Word width. On CDs word width is stored, the music signal with 44.1 kHz (i.e. 44 100 sampling values per second) and 16-bit representing 65,536 different gradations of volume or a maximum dynamics of 96 dB.
To regulate digital signals in the volume is technically feasible; because a level of digital zero is not possible, each level control corresponds to a reduction and thus a theoretical loss of momentum. For 16 bit signal processing is not recommended it. The digital volume control the ICE 502 therefore regulates all signals, also the CD play to 24-bit.
More consistently, it is in connection with a Backes & Müller active speaker of the BMLine series. These boxes have the ability to accept getting an uncontrolled signal of maximum dynamics on their digital inputs and only by using a control signal directly in the final stages analogous to adjust the volume. It has the theoretical advantage that the full digital dynamics is transferred and processed by the Digital FIR soft little songs controlled from and selected volume is low. The level is lowered before so really at the immediate end of the entire chain, in the respective amplifiers for bass, midrange and tweeters.
FIR turnout of BM15: be controlled from PC
The high performance DSP-based crossover the BM line 15 provides not only a coherent time and phase – distribution of frequencies in three ways. The computing power can be used also for extensive Equalizer features and space adaptation. The optional FIR-Control Software allows you to set three additional fully parametric filter in addition to the two broadband Shelve filters to adjust treble and bass acoustics and site. The latter can be adapted in usage frequency and quality, such as when a resonance or sound reflection narrow-band should be hidden in the room. A Delay function for centimeter-accurate distance correction is also possible. The software runs on standard PCs, the box is connected to the serial port by means of adapter and “remote-controlled”. Various EQ settings can be stored in and later play back to the box.
B&M ICE502 + BM Line 15 im Test
Aktivbox Backes&Müller BM 35
Aktivbox Backes&Müller BM 35
Datenblatt: Backes & Müller BM35