Edifier MR4 Studio Monitor review – Minimalist studio speakers for the small desktop and the even smaller wallet

Built-in chassis

The Edifier MR4 studio monitors are characterized by selected components that ensure a balanced and precise sound reproduction and have actually been optimally adapted to the price. The typical silk dome tweeter has a diameter of one inch (approx. 25 mm). The dome tweeter is made of silk with a special coating that ensures smooth and detailed high-frequency reproduction. Silk dome tweeters are known to produce less distortion and deliver a pleasant, not overly harsh sound for a rather affordable price. The tweeter covers the frequency range from around 2 kHz to 20 kHz and is designed to provide clear and precise highs

The cone woofer has a diameter of 4 inches (approx. 102 mm). It uses a polypropylene cone that is reinforced with MICA. This combination ensures a flexible yet rigid cone that enables a fast and precise response to audio signals. The built-in woofer covers the mid and low frequencies, typically from 60 Hz to 2 kHz. It delivers solid and well-controlled bass and clear mids, which are responsible for the majority of music and speech information. Of course, you can’t expect deep bass, but the lower limit of 60 Hz is ok.

Teardown: Housing

However, the cut-out for the rear plate as a platinum carrier is cut out in a rather adventurous way, which stands out visually from the otherwise cleanly manufactured housing. This looks like manual reworking to ensure that what belongs inside fits in again. The glued blocks serve to stabilize the side panels, which are glued together. You can do it this way, even if real triangular brackets would of course be more stable. But given the small dimensions, it’s fine. After all, hardly anyone is likely to unscrew it.

The tweeter sits firmly in a rectangular recess and is screwed in from the inside, the feeds are plugged in, not soldered.

In contrast to the R1280 Studio, there is also no free-hanging longitudinal capacitor soldered; this has been solved somewhat differently here using a separate cable (PCB with separate tap), even if it is not a genuine passive crossover as a more complex LC element.

Teardown: PCB and components

The main PCB with the amplifier and all inputs sits on the mounting plate already mentioned, as does the digital switching power supply; the loudspeakers and the front controls are connected with plug-in cables.

However, what at first glance looks like an active crossover (DSP with two channels for bass/mid and treble) is actually not. The longitudinal capacitor is located on the circuit board of the active speaker. A simple parallel circuit, whereby a longitudinal capacitor keeps the low frequencies away from the tweeter (behind the red plug on the left). However, the frequencies above 2 kHz are then also sent in parallel to the woofer/midrange driver, which is not really a great idea. But crossovers cost money…

The printed circuit board from Rong Hui Electronics (HUIZHOU) C0. Ltd suggests a TAS5713 from Texas Instruments in the imprint, but something completely different has been installed.

The AD82584D from EMST is also a 25 W stereo amplifier IC, designed as an open loop Class D. A 16-channel EQ and DRC are also on board. Theoretically, even 25 watts per channel are possible here (or 50 watts in a mono bridge circuit), but after simple measurements I assume a maximum of 10 watts of continuous sine wave per channel. This means that the manufacturer’s specifications in RMS should also be correct and you can do without a heat sink, as the circuit board is completely sufficient.

The PCM1808 is a high-performance, cost-effective single-chip stereo analog-to-digital converter with an unbalanced analog voltage input. It uses a delta-sigma modulator with 64-fold oversampling and includes a digital decimation filter and a high-pass filter that removes the DC component of the input signal. For various applications, the PCM1808 supports master and slave mode as well as two data formats in the serial audio interface. It is suitable for a variety of cost-sensitive consumer applications that require good performance and operation with a 5 V analog supply and a 3.3 V digital supply.

The TLV320DAC3203IRGET (sometimes referred to as DAC3203) is a flexible low-power, low-voltage stereo audio codec with programmable outputs, PowerTune functions, fixed predefined and parameterizable signal processing blocks, integrated PLL, integrated LDO and flexible digital interfaces. The extensive register-based control of power, input/output channel configuration, gains, effects, pin multiplexing and clocks allows the device to be precisely adapted to its application.

The whole thing is completed by various operational amplifiers, which brings us to the end. Practical and free of frippery. Switching between the Monitor (neutral) and Music (bathtub) profiles is done via DSP, as is the entire sound and volume control. Good and inexpensive.