® M44 Multisonic Imager ® M86 Multisonic Imager Oper ation Manual Miles T echnology Inc.
Miles T echnology Inc.
M44 and M86 Multisonic Imager Operation Manual ABOUT THE M44 and M86 ® Multisonic Imagers are precision electronic audio devices which enable a sound system to provide the many advantages of stereo sound to off-center listeners. They also improve the stereo sound quality for all listeners. Miles Technology's patented Multisonic Imaging System provides stereo sound localization using three loudspeakers for the front soundstage.
M44 and M86 Multisonic Imager Operation Manual M44 and M86 Quick Start Instructions 1. 2. If possible save the box, packing, and your Authorized Dealer sales receipt, which validates the warranty period if it starts later than the date of manufacture. For units without this documentation, the three-year warranty starts at the last day of the month of manufacture as indicated by the serial number. 5. For intended operation, three loudspeakers are needed. They are placed at left, center, and right.
M44 and M86 Multisonic Imager Operation Manual Contents 1 Multisonic Imaging Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 1 Multisonic Imaging Description ® The Miles Technology Multisonic Imaging System greatly enhances the acoustic sound quality of all stereo program sources using three loudspeakers rather than just two. Multisonic Imaging is an electroacoustic audio imaging process which increases the clarity, focus, and listening area of a stereo sound system while using any stereo audio program source. This is accomplished without the need for any special encoding process.
1 Multisonic Imaging Benefits ® The Miles Technology M86 Multisonic Imager will benefit a sound system in many ways: ® Multisonic Imaging With patented Multisonic™ Imaging, the “sweet spot” is enlarged to practically the whole room, allowing an entire audience to simultaneously hear great stereo sound.
1 Focused Center Sounds intended to be at front and center are clearly localized there with excellent focus and intelligibility for all listeners. This improvement, compared to traditional stereo, is dramatic. More Even Sound A “wall of sound” is created which provides more even and well-balanced sound distribution while maintaining correct localization. Listeners hear the sound stage, not the loudspeakers.
1 Applications There are many applications that can benefit from ® the use of Miles Technology's Multisonic Imaging: Auditoriums and Performing Arts Centers: The Multisonic Imaging system makes the often-desired left/center/right front-of-house system a convenient reality. Vocal intelligibility is greatly enhanced by the center channel, and overall music program subtleties are brought out.
2 Each side-channel output has a portion of the opposite channel subtracted, with the exact proportion and level for the side channels precisely maintained, according to the C/S Image Balance control position. The center channel is created by summing the processed left and right output signals. This signal will always be 6 dB higher (louder) with any center-panned signal information, compared to side-panned signal information.
2 front soundstaging. Furthermore, this switch can be left on all of the time (used for all 5.1 sources); in virtually all cases the sound will be improved. If a full 5.1 source is not used, the left and right connections of the 5.1 input can be used as an additional stereo input. In this case, the 5.1-toMultisonic switch should be pressed, and the 5.1 level control will act as a separate level control for this stereo input.
2 1 2 3 The Multisonic Imager 4 Fig. 3 M86 Front Panel 5 1 6 7 8 9 10 11 10 12 10 13 10 14 15 6 7 8 9 10 11 10 12 10 13 15 2 Fig. 4 M44 Front Panel Control Functions: Front Panel Refer to Figure 3 (M86) or 4 (M44). 1. Stereo Input LEVEL control: Adjusts the stereo-input gain and overall volume level; can be used to compensate for different incoming signal levels. All outputs levels will be affected simultaneously.
2 subwoofer. Or, when pressed, the filter prevents the subwoofer from reproducing higher frequency components of its program material. mV). The red light indicates the clipping distortion of the audio signal. The green light should flash with the signal most of the time; the red light should not light—if it does, the input or output level is too high. 7. L/C/R Output HPF switch: This applies highpass filters to the Left, Center, and Right Outputs.
2 Control Functions: Back Panel Refer to Figure 5 for M86 or Figure 6 for M44. 1. AC Input Power: This is for connection to the ac power mains. Be sure that the correct voltage is applied, according to the power supply setting you have. The voltage is set to either 120V or 240 Vac with inside jumpers (see page #). The unit may be left on indefinitely or switched with other equipment. When switching the ac power with other equipment be sure that the power amplifiers turn on last. 2.
2 The Multisonic Imager Specifications Front Panel Controls Stereo Input/Image: Level, C/S Image Balance, Surround 5.1 Input: Level, 5.1-to-Multisonic switch Discrete Sub Input: Low-Pass Filter switch Output Levels: Subwoofer Level, Center Level, Left/Right Level, Surround Level Output Switches: L/C/R Output High-Pass Filter, LC and CR Setup.
12 2 M86 Internal Block Diagram The Multisonic Imager Fig.
2 M44 Internal Block Diagram The Multisonic Imager 13 Fig.
3 3 System Design and Installation Equipment Selection The complete design of a multichannel sound system is complex and beyond the scope of this manual; however some basic guidelines are included here to illustrate the differences between multichannel and conventional or stereo systems. Multisonic Imaging systems are designed much like conventional stereo systems. The addition of a center loudspeaker, carefully integrated with the left and right loudspeakers, is the main difference.
3 Installation External Signal Processing General Concept The Multisonic Imaging System is easily implemented with various types of signal processing equipment. The number of channels needed depends on the specific application. Figure 9 shows a typical signal processing sequence for most applications. Generally, signal processing which is primarily intended to correct or modify the program material should be ahead of the M86.
3 loudspeaker (after the Imager). Each loudspeaker system can be equalized independently. This is applicable for clusters, multi-way systems, and unmatched center loudspeakers. However, if only one stereo source is to be used, then a two-channel stereo loudspeaker equalizer may be placed just ahead of the Imager; this way it will correct all of the loudspeakers (left, center, right, left surround, right surround, and sub).
3 Room Acoustics The optimum achievable quality of stereo imaging is very dependent on the room acoustics. Generally, the deader the room, the better the imaging. Live rooms provide their own ambience which can be detrimental to the sound system. Any hard flat surface, of large area, will create sound reflections which can be especially harmful to imaging and overall sound quality. Such surfaces may need acoustic absorption treatment, especially if they are near or opposite the loudspeakers.
3 the maximum listening area with best possible imaging while keeping the center loudspeaker from being too far away. This is a goal; in practice, there is quite a bit of flexibility in the exact placement. If possible, the left and right loudspeakers should about as far apart as the width of the stage or performance area. Installation loudspeaker needs to be located more in line with the left and right as shown in Figure 12.
3 level to compensate for the increased distance to the listeners. The Center Loudspeaker The center loudspeaker should be equidistant from the left and right loudspeakers. Whenever possible, it should also lie on a plane formed by the listener and the left and right loudspeakers. That is, it should be horizontally aligned from the listener∗s viewpoint, as shown in Figure 14.
3 a Multisonic array just like the front. Also the sides can be set up the same way for very effective side imaging. An M44 Imager is used for each sound stage array. System Interconnection Grounding and Balanced Cable Connections As with any signal processing equipment, the M86 should have its chassis grounded. Proper chassis grounding will ensure both user safety and maximum RFI protection. This is achieved by plugging the line cord into a grounded outlet.
3 Bridged Center Connection With One Stereo Power Amplifier One characteristic of Multisonic Imaging is that the center-loudspeaker signal is always an exact electrical sum of the left and right signals. Therefore it is possible to connect the center loudspeaker in a bridging configuration so that one stereo power amplifier can drive all three front loudspeakers. This economical approach is useful for systems which will utilize only two-channel stereo (left/right) signal sources.
3 Setup Adjustment Procedure This setup adjustment will produce correct level balance of all of the loudspeakers so that Multisonic Imaging operates perfectly. Typically the levels are set using the amplifier gain controls, while the Imager’s output controls are straight up. Although the description here is quite detailed, this procedure is really very simple, and often can be done in just a few minutes.
4 should sound like the center loudspeaker is actually on, even though it’s disconnected. 6. Reconnect the center loudspeaker and return the LC and CR Setup switches to the out position. 7. Correct system connection and operation can be verified using the LC and CR Setup switches independently as described in sections A1-A8 above.
4 Many recordings are recorded with a somewhatnarrow sound stage. This studio mixing approach provides more consistency for monophonic reproduction. By setting the C/S Image Balance control toward "sides", perhaps at the 1 o∗clock or 2 o∗clock position, a full-width perspective can be restored without sacrificing image clarity. Some recordings are recorded with a wide image, or they may seem to have a weak central area.
4 Normally the C/S Image Balance control is left centered. However it can be used to change the pan control range available at each input of the mixing console. M86 Operation Vocal Cancellation When set slightly toward Center, it will limit the pan control range to a narrower soundstage. This may be useful when the left and right loudspeakers cover most of the audience and stereo soundstaging at the fringe areas is a priority.
5 Troubleshooting Guide 5 Troubleshooting Guide System Problems No output Check if the Power indicator is on. If not, check the power supply connection and make sure the ac outlet is on. If the Power indicator is on, then check the Level controls and all input and output connections. If everything seems to be in order, and there is certainly an input signal, but there is still no output, call customer service.
5 Troubleshooting Guide near a power amplifier or any big power transformer. Try increasing the distance to any nearby power equipment. Sometimes RFI can induce hum in the system. This could result from a nearby transmitter or a lamp dimmer on the ac line. If proper grounding technique does not solve this, then an RF filter for the ac line (such as Radio Shack 15-1111 for moderate suppression) might be helpful.
5 Troubleshooting Guide Balance is off; sound is lopsided Check the program source for channel balance. This symptom is usually caused by an unbalance in the source. Compare with Mono source material. Make sure the amplifier gains are set correctly with the setup procedure. Won't image left or right Verify the polarities of the loudspeakers. This is done with the setup procedure. You should be able to hear solid phantom imaging at left-center and right-center.
6 Product Support Sound Quality Weak bass Verify correct polarities of all loudspeaker connections. If an external active crossover is used, make sure it is set up correctly. If the low bass is to be summed to mono, use only the center output of the Imager. This will be very effective for crossover frequencies around 100 Hz or lower. Weak dialog This problem sometimes occurs with surround-sound movies, and in general it is due either to a poor mix or excessive dynamic range.