Metrum Acoustics, Dutch made DAC’S, Heard Globally!
Metrum Acoustics is a leading manufacturer of a well-formed range of Digital to Analogue converters, Digital Pre-Amplifiers and Power Amplifiers.
A brand of ALL-Engineering BV, Metrum Acoustics has continuously made waves in the national and international press with the unique sound of its DACS.
Starting in 1989 with electrostatic speaker field developments, the company over time evolved in a leading Digital to Analog conversion product company. Today Metrum Acoustics is a household name for artists, music professionals, audiophiles and lovers of sublime sound alike!
Throughout the existence of Metrum Acoustics, a diverse range of acoustic system products have been created, always relying on sound electronic design principles. Digital signal processing has played a significant role in more recent developments.
In hi fidelity audio Metrum Acoustics attention was initially drawn to the limited availability of certain componentry. Established manufacturers supplying these key components decide how signals should be processed. No alternatives are available and therefore this greatly influences the sound image that is realized.
Current trends among manufacturers are to use the technique of ‘oversampling’ or ‘up sampling’ within the digital to analogue chipset itself. This forces designers to utilise this method of signal conversion for their own products. It also means that many brand systems use the same building blocks and consequently sound the same. The sound images created by such systems can betray the componentry that has been implemented. These sampling techniques were introduced to fulfil the need ‘to smooth’ the conversion process from digital to analogue and prevent phase distortion. Particularly during the years following the introduction of CD replay, conversion methods proved insufficient regarding sonic artefacts. In response, strong filtering methods were employed and the oversampling technique was born. These techniques however had disadvantages which manifest themselves for example in areas of transient response.
Headquartered in the Netherlands, Metrum Acoustics was founded by Cees Ruijtenberg who started his career in audio with electrostatic loudspeaker panels and amplifiers. The company started to expand as of 2010 with the introduction of its first DAC, in a market which is growing year over year because of growing enthusiasm and adoption of streaming music offerings like ITunes, Tidal, Deezer, Spotify, SiriusXM and many others.
One of the reasons what makes Metrum’s products unique, is the fact that we use our own DAC chips, branded Transient. Transient is not only used in Metrum’s own product line up, but also used in various OEM products in the audio market. Besides the fact that Metrum products do have a unique sound because of its own DAC chips, is that we apply the Non-Oversampling (NOS).
Converting data into an analogue signal is the name of the game for digital music systems. So, plugging in a dedicated DAC can only improve things right.
Delivering precise digital to analogue conversion is difficult. It requires the use of the best available components, but also extreme care and attention to the engineering of the power, the clocking system and the output circuitry. Otherwise the sound is compromised before it even arrives at your music system.
And this is where Metrum Acoustics stands out.
Today there is a growing view that ‘non-oversampling’ or NOS for short, offers many benefits but without the compromises mentioned above. AE dedicated considerable time and attention to researching the NOS premise and found its audible benefits valid up to a certain point. The question then remained how to remove these sonic artefacts without resorting to oversampling. This question was answered by the first product made by AE the NOS mini DAC Quad, a digital to analogue converter designed and manufactured with modern high speed industrial grade chip sets, free from most of the disadvantages of the past. These techniques are improved over time and used over the entire range of products. The most important result is the sound, which was never so close to the analogue origin.
Metrum Acoustics has been visionary in NOS, hence the reason so many audio users worldwide have adopted one or more of Metrum’s DAC’s.
All the designs made by Metrum Acoustics are manufactured in house, which means that we have full control over the production process, including the print designs, documentation, software, manufacturing and quality assurance.
A relatively simple NOS Mini DAC was the first Metrum DAC, a competitively priced DAC that shocked the hi-fi community because it offered such high quality. This converter was the first to use a high speed R2R ladder converter made for industrial rather than audio purposes. The Mini DAC was soon followed by the more sophisticated Quad and Octave DACs, the latter using external power supplies. One step leads to another and having started with two DAC chips (Duo), Metrum moved onto four (Quad), eight (Octave) and finally the sixteen converters in the Hex, a DAC that was extremely well received in the audiophile community. The AURIX headphone amplifier for the expanding personal audio market became available in 2013. After that came the PAVANE DAC, the product that prompted the press to go crazy over Metrum Acoustics quality products. The latest audio products are the JADE, a Digital Pre-Amplifier and the ONYX, a powerful DAC with superior sound quality.
The first Metrum DACs were literally made on the kitchen table, but they became so successful that Cees approached an engineering company to take over production. Not much later this cooperation led to a new partnership. This company works for industrial suppliers and OEM companies and can meet the high-quality standard set by Metrum Acoustics. Both companies gained from the partnership; Metrum Acoustics no longer needs the kitchen table and can rely on modern production and logistics capacity, meanwhile All Engineering uses Cees for some of their design and consultancy work. Metrum Acoustics delivers its products to any place in the world through a dealer network, or direct to customers if no dealer is available. Worldwide delivery is just one of the reasons that Metrum products need to be extremely reliable, no one wants to send repair jobs around the world.
All circuits are designed from scratch, followed by board layouts and pre-production samples. As soon as the definitive circuit board is ready for production and components are ordered, a third company starts producing the empty boards. When these come into the warehouse they are made ready for SMD components by using a template to apply a paste of glue and solder to the spots where the small parts will stick. A large machine using rolls of SMD parts, places each chip, capacitor, resistor etc. on the board. The next step is to put the stuffed board in an oven, where the glue particles vanish and the components sink into the solder. This is the basis of what is called Surface Mount Technology (SMT) which is very reliable, parts can be small and processors measuring only 17x17mm with 256 connection points on the bottom can be soldered in place. Bigger parts like power capacitors need to be placed by hand and fixed using a solder wave bath to make the connections.
The finished boards are visually inspected by comparing them against a photographic reference. A job done by a machine that shows if parts are missing, incorrect or not exactly in place. This comparison is far more reliable than can be done by eye, primarily because machines never get tired. Connections are checked from samples under a stereo microscope, which is also used to make minor adjustments on the boards when they deviate from the master.
The next step in the process differs for Metrum Acoustics finished products and Transient (OEM) boards. OEM boards are electrically tested without attaching wires, using pins that connect to the printed circuit boards from a template and connecting them to measuring equipment. The Metrum Acoustics products are tested as soon as they are built into their housing and all wires are in place, soldered or pushed into the connections. This is followed by a 24-hour burn-in for each device. After the burn-in the same measurements are repeated before the casework is closed. It’s a lot of labor intensive work, but it makes sure that failures are kept to an absolute minimum.
The PAVANE DAC was the first to use Metrum’s Transient modules. These contain industrial R2R ladder converters and additional circuits. A small piggyback board holds the FPGA based Forward Correction Module, splitting the 24-bit digital signal into two 12-bit streams before actual conversion to analogue takes place. The FPGA works at a 400MHz clock speed and applies the algorithm Metrum Acoustics uses for this technology, an approach hardly ever seen before in conversion products for (high end) audio.
Today Metrum Acoustics is a thriving manufacturer of Digital to Analogue Converters, Digital Pre-Amplifier and Power Amplifiers. We are growing everyday with the loyal support of our clients, the ongoing recognition by press and reviewers and are dedicated to bringing new exciting audio products to market.
Metrum Acoustics Cees Ruijtenberg has seen his dream come true, the dream of bringing superior sound to music lovers of all origin, and with the ever growing and dedicated team will continue to do so.