DAC Audiolab M-DAC
Externally, the M-DAC is markedly different from all the converters, which are still offered the audio industry. It is relatively small and lightweight, powered by an external adapter, but at the same time looks like a very serious device. The rear panel of five digital inputs: a pair of coaxial, pair of optical and USB. Output terminals too much: digital presents jack TosLink and coaxial, analog - linear stereo pair RCA and balanced XLR. There are also additional slots and intended to connect the IR control system components Audiolab. Contrast monochrome OLED-display on the front panel displays a lot of information. On the "facade", in addition to the usual input selector button, there is a rotary volume control (he and balance control), digital filtering mode switch button, enter the setup menu and dialing out. As you can see, the functionality M-DAC, rather similar to the pre-amplifier. And the parameters and capabilities will significantly outperforms 8000DAC - previous DAC Audiolab, released in 1992.
The "brain" of novelty is a 32-bit high-performance chip ESS Sabre32 9018, capable of processing within a digital audio with up to 84.672 MHz. Of course, with external sources of M-DAC runs on standard sampling rates - up to 96 kHz/24 bit on optics and USB and up to 192 kHz/24 bit through the coaxial input. Analog output stages, developers also not saved by applying high current balanced circuitry in class A. Yes, and all the other units converter made to the conscience. Digital section is mounted on a four-layer circuit boards, resistors are used throughout with minimal deviations, capacitors - either foil or ultra internal resistance in the food chain ten low-noise regulators. For the device cost about $ 1,000, in addition manned remote control, all very convincing and promising.
But the most interesting offer if you press Menu. It displays an extensive interface settings, where you can set the sample rate of the digital output, the types of information displayed on the display, turn the volume control via USB, turn off the volume control on the analog outputs, thereby making them fixed on the level. This - not all. On the menu you'll find a few unique features: testing for bit-fidelity, restoration LSBs and D3E-correlator.
The first will allow you to make sure that the chain from the source is working properly. Test is carried out for any input, just need to pre-load the site Audiolab special text file and transferred to digital media to play it during the scan. But by and large in the testing need only input USB. And certainly the first exam on the "originality" will fail. The fact that the data that you get a computer, do not often follow a bit-by-bit, simply because they pass through the built-in audio mixer further processed by the processor are recorded in its internal devices, etc. The instructions to the M-DAC is explained in detail how to properly configure the drivers on your computer, music player and other software components of Windows Vista, Windows 7 or Mac OS, to obtain data on the converter is bit-for-bit identical with the code to play audio files.
Another feature is also related to the quality of sound. In converter Audiolab integrated analyzer so-called "fixed structures" found in the data stream. As a rule, they have no relation to the original audio information, and appear in the quantization process and digitization in the form of a regular second harmonic. And these unwanted processor modifies the structure on the basis of a certain probability model, ie "dilutes" random data. And there are two degrees of processing - with partial substitution of structures or complete.
The developers claim that the decorrelator D3E very effective in eliminating the "digital" harmonics. But on hearing the change of regimes decorrelator indistinguishable - perhaps because those "fixed structure", with which he intended to fight, are rare and very short-lived. But as they say, and thank you for this. At least, D3E works delicately and precisely does not spoil anything. This is not a mandatory primitive "soaping" Noise Shapping in the CD-players twenty years ago.
Deserve a separate description implemented in the M-DAC digital filtering algorithms. The main one is the most advanced Optimal Transient, which has three sub-mode processing of low-level signals. In technical terms, it is formally degrades the signal, but gives a gain in the subjective perception of digital sound. These algorithms are effective in suppressing high-frequency oscillations (eg, ringing) that occur during the conversion in the signal amplitude to the rapid release and beyond.
Other modes are represented by the following set: traditional filtering algorithm Sharp Rolloff a slump outside the playback range; Slow Rolloff with gradual decline; Filter Minimum Phase, not giving anticipatory vibrations, but not too effective in suppressing the subcarrier frequency sampling; Optimal Spectrum, implemented in the mathematical model of quantization and does not rid of the digital "ringing".
Now how all this affects the sound. Basically position Optimal Transient XD sound processor does not cause any issues at all. It is ordered, there is no apparent anomalies in the scene or in the dynamics of any tonal balance. At the edges of the range is not lost musical information, in the middle register nothing dissonant in the upper band of the overall cleanliness. M-DAC on the music data in this mode can be compared to any available audiophile DAC.
Switching to Optimal Transient DD revives the sound makes it subjectively more "large". As if the added dynamics in the space of an additional depth, all of the virtual sources are becoming more corporal, a side effect is only a "ballooning" of the sound images. With this setting, pleasant to listen to large symphonic compositions. As if transplanted from the back rows closer to the stage.
The third mode, which is simply called Optimal Transient, on the contrary, is not impressive. It feels as if the signal passed through the squelch. Playing becomes softer and more delicate, sharpness out of it, but lost significantly and detail (especially against the background mode Optimal Spectrum, which later). But at the same time - brightens the scene! Probably, such an algorithm is useful when listening to soundtracks that are recorded too hard, in digital. Other use I can not see him.
In position Sharp Rolloff sound after all these settings immediately seems less enjoyable. More bass, but it is less picky. In the upper register is added "tin" shades. Switching to Slow Rolloff helps loosen stain on the top and in addition to making the middle of a convex, but the sound is already some "flashy". Plus, this function can only see that it gives perhaps the most informative playing in the middle register. Benefits of Minimal Phase appear only in the bass and sredenechastotnoy bands. The sound is well developed, endowed with force, conquering harmonic richness. But in the upper range of dynamics and clarity is not added - is just some semblance of abundance trebles. Algorithm Optimal Spectrum enjoy all digital maniacs only. Intense sound, the impression of the most detailed, although this feeling is deceptive. Scene as if filled with some unhealthy unheard-ringing energy. And the focus, and the separation in place, but not the contour and explicit, as in the default mode.
However, the developers even in the instructions to the M-DAC warns all modes except the default, serve only to compare. Otherwise, how to know the digital sound?
