Subwoofer Audio Pro Mondial S.3
Get the speaker system low bass is quite simple - you need to take a 18-inch speaker and put it in the body size of a refrigerator. And make a professional stage acoustics, but for home systems, this method is not always appropriate. With the advent of home theater subwoofers have become huge demand, forcing acoustic engineers to find new ways to solve the classic problem - how to get a deeper bass in a compact package. The most promising developments, in my opinion, are the super-efficient sound absorbers such as activated carbon (it successfully uses KEF), and servo sensor controlling the displacement of the diffuser.
The latter method is rather complicated for practical implementation - amplifier with a positive operating system can become a generator, if the phase and frequency characteristics of the entire tract will not be strictly optimized. Swedish engineer Carl Eric Steil in 1978 figured out how to solve the problem, and in the same year was created by Swedish subwoofer B2.50 same company Audio Pro. The demonstration, organized in New York on the 61 th Conference of AES, is a sensation and brought fame to the manufacturer. The system has been patented under the brand name ACE-Bass (Amplifier Controlled Euphonic Bass) and used for 30 years in active subwoofers Audio Pro.
The principle of action of ACE-Bass consists in that the high-speed circuit monitors the displacement cone (more precisely, the voice coil) and optimizes the amplitude of the output signal of the power amplifier. General feedback thus obtained is positive, and the output impedance of the amplifier - negative. Accordingly, reduced distortion, improved electrical damping of the head, and the control of the moving system can improve its return on frequencies below resonance.
For a more exact alignment parameters of the amplifier and the bass head operating range model Mondial S-3 is limited to 100 hertz, although usually working to 150 subwoofers It narrows down the scope - from subcompacts or flat satellite unit will not dock. But this disadvantage is compensated by the ability to reproduce low bass: the diffuser diameter of 8 inches (200 mm) lower bound is declared (and confirmed by our measurements) at 27 Hz. Acoustic design - bass reflex, its port in the form of a narrow slit is on the rear wall. Built-in amplifier has an output of 200 W RMS, which is sufficient for scoring rooms up to 30 - 40 m2. Massive heat gives us hope that it works in a traditional class AB, and not pulsed D.
The list of standard regulations: level cutoff frequency bass within the 50 - 100 Hz and phase inversion 0/180 deg. But there is a very useful feature that extends the capabilities of the subwoofer - the presence not only of "hot" inputs, but also outputs. And on the last signal is fed through a filter with a cutoff frequency of the RF 100 Hz and a slope of 6 dB per octave. Thus, Mondial S-3 is very easy to integrate into the system for both home cinema and hi-Fine 2.1 - band playing satellites will be limited from below by the subwoofer. Turn on when the signal on any of the inputs.
The exterior of the bass machine matches the style of the entire line of Mondial. Root shell is made from MDF and covered with imitation leather, which gives it a somewhat exotic, yet stylish look. Not to leave fingerprints on porous surfaces, you can use the white gloves, available in the kit. Grill tight recessed flush with the frame, which eliminates jitter and other unwanted overtones. Made unit carefully and, despite its compact dimensions, rather massive. Inclusion is indicated by two LEDs - blue front and red rear.
Setting a cut-off frequency of 80 Hz, I connected the subwoofer to the AV-receiver Sony STR-DA5300ES. The menu has designated our front speakers Monitor Audio Gold Reference 20 as "small", although in fact it is quite large and deep voice. Bass machine confidently seize the initiative in the lower register, adding to the sound of a fair amount of subsonic components. Sounding Mondial S-3 is different from most competitors is very quick response and the ability to reproduce the sharp claps, just shoot, which is why the sound of a drum kit is surprisingly natural. The only thing that can be criticized Swedish engineers - for a speed-section diffuser reflex is insufficient, and the air coming out of the slot with a characteristic rustle. But note overtones outsiders can only at high volume, and then if you put the subwoofer close to a wall. Theatrical special effects are transmitted more than adequately, ie with depth and energy inherent in a more powerful large-caliber drivers. The subwoofer is very easy to operate - it is very sensitive to the settings specified in the menu system, and gives the output exactly what it wanted to achieve from.
A musical material also feels good speed, lower case seems big, but sometimes somewhat simplified. But we're talking about a compact subwoofer with 8-inch head, and with such dimensions require more simply is not fair.
