In his own words, John Jefferis explains the INs and OUTs of Bass Delivery MJ Style

“First and foremost, MJ Acoustics is an audiophile Company. We take great pride in designing and building products with exceptional performance. Because of our total commitment to performance, we more often than not, adopt unusual solutions to otherwise straightforward problems.

All MJ subwoofer products are designed to be used with both High-Level (loudspeaker) inputs and Line-Level inputs, together if required. We only use the highest quality connectors. For example, the High-Level connectors are not the usual cheap binding posts, or those horrible, spring-loaded connectors. MJ uses Neutrik Speakon connectors for these critical connections. The Speakon ensures a gas-tight connection, which does not deteriorate with age. The line level uses high quality panel mounting Gold Plated RCA phono connectors. To allow independent control, the High-Level and Line-Level inputs have separate volume controls on all models, some with Twin Crossovers also. This is why an MJ product is equally at home in both an exclusively 2-channel audiophile system as it is, in a multi-channel, surround system used with Hi-Definition 192Khz audio or Home Cinema. Perhaps even more importantly, they can be used with both systems connected so that the user can choose whichever they wish and still enjoy the benefits of the MJ Sub-bass system.

We always recommend that the audiophile connects to their system using the Neutrik high-level connector or when provided an additional set of Line-Level Pre-outputs from a Pre-Amplifier. The reasons for this are two-fold.

Firstly, in the case of only one set of Pre-outputs from a Pre-amplifier, it is simply absurd to have a very high quality preamp in your system and then load it with a sub in parallel with the power amplifier. There are circulating currents within the signal ground and these can cause mutual coupling within the signal ground of the preamp. At this stage, the delicate signals are at their most vulnerable. The direct connection between pre and power amp is the best choice for an audiophile connection.  More modern and costly pre-amplifiers provide for an additional set of outputs that are independent and fully buffered from the main set and duplicate this output.  This type of connection is also excellent.

Secondly, by connecting at high level the subwoofer will receive exactly the same signal quality of bass as the main speakers. The overall quality of reproduction in a system consists of the main speakers, the amplifier and the room acoustics. Change any one of these and the sound will change. One of the most critical aspects of adding a subwoofer is that it should integrate into the main audio system. By ensuring it receives the same quality and dexterity of bass as the main speakers, helps to achieve this.

This is further augmented by our design of Bass frequency Control filtering. We always allow the user to set this from 20 Hertz up to 120 Hertz. Many of our rivals offer an inferior setting, often up around 50+ Hertz. Remember our lowest setting of 20 Hertz determines the upper knee of the sub’s frequency response. The lowest frequency of the subwoofer is always below this and is totally unaffected by the filter settings. In other words, the filters just limit the upper frequency response of the sub.  If you input 5 Hertz you will get 5 Hertz output.

Why choose such a low setting for the filter setting? Because this ensures that an MJ can be integrated into virtually any system, no matter how large the main speakers. Remember, integration is the essential goal in a high quality system.

To further ensure tight integration, by offering  121 discrete musically correct steps on the Crossover filter with our Reference and Master-Class series. The infinite adjustment so accurately settable is the backbone of audiophile integration. Many other subs will be boosting the main speakers’ sound, whether the listener wants it to or not.

We are often asked: “Are two subs better than one?” Two subs will help iron out the usual room response peaks and troughs. It also more than doubles the dynamic range and offers a tighter and more controlled bass. There are also spin-off benefits to the way we perceive that sense of “air” around instruments and the feeling of acoustic depth in a recording. These are subtleties that are totally masked if the sub is not correctly integrated into the system. Two separate and carefully positioned bass producers help achieve these subtle improvements.

Another question often asked is: Are two large main speakers better than two smaller ones, plus a subwoofer?” No.  With a large speaker, there is more boxy radiation as the larger the cabinet sides the stiffer a cabinet must be manufactured to compensate. This is inevitable and actually gets worse the larger you go in cabinet size.  Consider, also that two very large speakers obtained to get more bass output will not provide the integration of bass that a subwoofer in the system can.  Substantial vibrations from the main speaker bass driver will affect both the midrange unit and worse, the delicate tweeter driver. These extra vibrations are radiated into the room and mask the stereo sound image. Additionally, the bass driver in a multi-unit system is fed via a passive crossover. This crossover puts an impedance between the bass unit and the power amplifier meaning the amplifier has less control over the main speakers bass driver.  There is far more risk of “room boom” with a larger speaker, particularly in a smaller room.

It follows then that no matter what size your main speakers are, you need a subwoofer to provide the bass in the lower octaves that are not being released from the main speakers.  The final point is the simple fact that what goes into a speaker does not come out.  A speaker is a passive device that can only attenuate the signal at frequency specific points to make the bass sound more proportional to the mid-band and upper frequencies.  Only an active speaker could do this and the subwoofer is the active part of the system that provides the integration of bass with the mid-band and upper frequencies.

With the right design of subwoofer, this is not a problem. The MJ sub-bass is simply dialled in up beneath the main system (using the DAMP 3rd Gen crossover), such that “room boom” is totally avoided. However, the very deep bass that is felt rather than heard, is still comfortably within the range of the system. When one remembers that the additional benefits of removing the bass vibrations from the main speakers help ensure a cleaner signal, there is a further reason to opt for an MJ sub in combination with aesthetically pleasing smaller speakers.  Quite often it is the addition of a subwoofer from MJ that makes the biggest impact on improving an audio system as a whole.  Many times we have seen that people have been delighted to keep their beloved main speakers as the addition of bass in the lower octaves had hitherto never been presented to their ears before in a way that only an MJ sub-bass system can do.  Benefits of experiencing a fuller bandwidth system offer improved transparency and stereo imaging which are aspects of audio performance that provide far greater value than the extra simply bass!

There is an old saying that we recite from a Rolls Royce design engineer responsible for developing the integrity of the fan blades in jet engines, “the quality will be remembered long after the price is forgotten”.  This very much epitomises the ethos behind the design of all MJ products.

When its sound right it is just simply REAL!

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