Midiplus MI 5 - active Bluetooth monitors
The Midiplus brand is becoming more and more recognizable in our market. And that's good, because it offers functional products at a reasonable price. Such as the compact monitors described here.
M.I. five belong to a group active two-way loudspeakersin which we feed a signal to only one monitor. We will also find it in him volume control and power switch. This solution is based on an active-passive structure, in which all electronics, including power amplifiers, are placed in one monitor, usually the left one. The second is passive, receiving a loudspeaker level signal from the active monitor, that is, several or tens of volts.
Usually in this case, many manufacturers go for a simplified approach, connecting the speakers with a single-pair cable. This means that the monitor is not two-way (with separate amplifiers for i), but broadband, and the split is done passively using a simple crossover. This often comes down to a single capacitor because it is the easiest and cheapest way to "separate" high frequencies from the entire audio spectrum.
True two-channel amplifier
In the case of M.I. five we have a completely different solution. The passive monitor is connected to an active four-wire cable, and this is a sure sign that the monitors offer active bandwidth sharing and separate amplifiers for and. In practice, this translates into the possibility of more accurate frequency shaping and filter slope in the crossover, and, as a result, a more controlled reproduction of the key sound of the group from the crossover frequency.
Someone may pout: “What difference does it make, because these monitors cost less than 700 zł - for this money there are no miracles! Plus that Bluetooth! In some ways, this is correct, because for this money it is difficult to buy the elements themselves, not to mention all the technology behind the monitors. And still! A bit of Far Eastern magic, exceptional efficiency of logistics and optimization of production costs, incomprehensible to Europeans, contributed to the fact that for this amount we get a rather interesting set for listening to a home studio or multimedia station.
design
The signal can be entered linearly - through Balanced 6,3 mm TRS inputs and unbalanced RCA and 3,5mm TRS. The built-in Bluetooth 4.0 module can also be a source, and the total signal level from these sources is adjusted using a potentiometer on the rear panel. A switchable shelving filter determines the level of high frequencies from -2 to +1 dB. The electronics are based on analog circuits., two amplifier modules operating in class D, and a switching power supply. The build quality and attention to detail (such as the acoustic insulation of the speaker jacks and TPCs) speaks to the serious approach of the designers to the theme.
The monitors are sold as a pair, consisting of an active and passive set, connected by a 4-wire speaker cable.
In addition to the three types of line inputs, the monitors offer the ability to send a signal via Bluetooth.
monitors have a bass-reflex design with a direct output to the rear panel. Due to the use of a 5-inch diaphragm with a fairly large diaphragm deflection, it was necessary to use a case with a depth somewhat greater than would seem from the proportion of the dimensions. A passive monitor has no electronics, so its actual volume is larger than that of an active monitor. This was also thought of, adequately compensating for this by increasing the amount of damping material.
The working diameter of the woofer diaphragm is 4,5″, but according to the current fashion, the manufacturer qualifies it as 5″. Woofer is installed in the recess of the front panel with profiled edges. This is an interesting and rare design that allows you to increase the acoustic diameter of the source of low and medium frequencies. The tweeter is also interesting, with a 1,25″ dome diaphragm, which has practically no analogues in this price range.
idea
performs its function when playing bass from 100 Hz and above, and in the range of 50 ... 100 Hz it is courageously supported by a very well-tuned bass reflex. The latter, given the dimensions of the monitor, is relatively quiet and does not introduce significant distortion. All this speaks of the optimal selection of elements and a thoughtful, well-made design.
The frequency response of the monitor, taking into account the three positions of high-pitched filtering. Below are the characteristics of the 55th and 0,18th harmonics for all filter settings. The average THD is -XNUMXdB or XNUMX% - a great result for such small monitors.
At mid frequencies, it begins to lose its effectiveness, which drops by 1 dB at 10 kHz. Here you always need to find the optimal balance between factors such as price, bass processing quality and distortion level. This is a real balancing act on a fine line, and even manufacturers who are recognized as leaders do not always succeed in this art. In the case of MI5, I have no choice but to express my respect for the work done by the designers, who knew very well what and how they wanted to achieve.
Frequency characteristics of individual signal sources: woofer, tweeter and phase inverter. Skillfully selected split parameters, high-quality drivers and an exemplary design of the bass-reflex port make the monitor sound very interesting.
The frequency separation is 1,7 kHz and the driver reaches full efficiency at 3 kHz. The slope of the crossover filters was chosen such that the total loss of efficiency at the crossover frequency was only 6 dB. And since this is the only price you have to pay for smooth processing of frequencies up to 20 kHz, I really like such things.
Comparison of characteristics and harmonic distortion when playing a signal through a line input and a Bluetooth port. Other than the delay seen in the impulse responses, these graphs are almost identical.
I don't know where the developers got this driver from, but this is one of the most interesting compact dome tweeters I've ever heard. Since it has a diameter of 1,25″, rare even in what are considered professional monitors, it can easily take on processing from 1,7kHz while maintaining an average second harmonic level of -50dB relative to the fundamental frequency (we are talking about just 0,3, XNUMX%). Where do the seams come out? In the direction of distribution, and in view of the desktop nature of these monitors, it does not matter at all.
On practice
The sound of MI 5 looks very solid, especially in terms of price and functionality. They sound friendly, intelligible, and despite their lower mid-range efficiency, they represent the bright side of the sound, maybe even too bright. There is a solution for this - we set the top-shelf filter to -2 dB, and the monitors themselves are set to “slightly divergent squint”. As long as the room isn't pulsing with traditional home studio 120-150Hz, we can expect quite a reliable listening experience during arranging and initial production.
Bluetooth playback is almost the same as cable playback, except for about 70ms of transmission delay. The BT port is reported as MI 5, offering a 48kHz sample rate and 32-bit floating point resolution. The sensitivity of the Bluetooth module has been significantly increased by installing a 50 cm antenna inside the monitors - this is another proof of how seriously the designers approached their work.
Summation
Surprisingly, given the price of these monitors and their functionality, it's hard to talk about any shortcomings. They will definitely not play loudly, and their accuracy will not satisfy the needs of producers who love complete control over impulse signals and selectivity of instruments. The lower midrange efficiency is not for everyone, especially when it comes to vocals and acoustic instruments. But in electronic music, this function is no longer so important. I could assume that the sensitivity control and power switch are on the back, and the power cord is permanently plugged into the left monitor. However, this is not something that affects the functionality of MI 5 and its sound.
With their price, decent workmanship, and attention to sonic detail in playback, they're perfect for starting your music-playing adventure. And when we grow out of them, they will be able to stand somewhere in the room, allowing you to play music from your smartphone.
See also:
