Electro-Voice MTL-2B User's Manual
Contents
1. Materials 14 ply birch plywood Finish Black carpet Hanging Two point flying system tracks accept Kinedyne 32102 1 and 32111 1 fittings Dimensions Height 91 4 cm 36 00 in Width 57 2 cm 22 50 in Depth 75 9 cm 29 88 in Net Weight 78 9 kg 174 Ib Shipping Weight 83 9 kg 185 Ib DESCRIPTION The Electro Voice MTL 2B low frequency loud speaker system is a member of the family of Manifold Technology MT loudspeaker sys tems designed for high level sound reinforce MTL 2B Manifold Technology Low Frequency Sound Reinforcement System EVX 180A woofers for explosive impact reliable bass Smaller MT rectangular enclosure High acoustic output low distortion Manifold Technology enables smaller and lighter loudspeaker arrays MT systems with different coverage patterns and output capabilities may be mixed and matched Unique rigging scheme for flexible array design and quick assembly Available without rigging hardware ment in concert sound touring and permanent installation applications The MTL 2B is a manifoided vented box low frequency system with a rectangular enclosure utilizing two very high power 18 inch woofers This configuration results in remarkably high acoustic output from a small enclosure The MTL 2B may be com bined with other members of the MT 2B and MT 4B loudspeaker family The combination of the MTL 2B loudspeaker system and the MTH 2B midbass mid frequen2. acoustic output Itis therefore highly recom mended that a high pass filter be used to pro tect the system against subpassband signals A high pass filter 3 dB down at 32 Hz with a minimum slope of 12 dB per octave is sufficient to provide adequate protection for the MTL 2B Without protection subpassband signals may bottom the woofers i e cause the voice coils to strike the back plate which can result in damage to the speakers Even if bottoming does not occur the subpassband signals waste amplifier power cause undue mechanical stress on the speakers and result in high levels of loudspeaker distortion USE IN MULTIPLES MTL 2B systems may be used in multiples to increase acoustic output When two loudspeaker systems are placed side by side a 6 dB in crease in maximum acoustic output power is possible at low frequencies assuming all woof ers are operating with the same polarity This increase occurs because at low frequencies the woofer cones from the two systems mutu ally couple acting as a single cone with twice the area and therefore twice the efficiency providing a 3 dB increase in sound pressure level The second 3 dB comes from the dou bling of the power capacity by adding a second system Mutual coupling occurs when the cen ter to center spacing between the two loud speaker systems is approximately one half wavelength or less When the spacing is greater than one half wavelength as would occur if t
3. Electro Voice SHOWN WITHOUT GRILL SPECIFICATIONS Frequency Response measured in farfield calculated to one meter on axis swept sine wave one watt input into LF midband anechoic environment see Figure 1 37 200 Hz Low Frequency 3 dB Down Point 45 Hz Usable Low Frequency Limit 10 dB down point 35 Hz Half Space Reference Efficiency 6 8 Long Term Average Power Handling Capacity per ANSI EIA 426 A 1980 see Power Handling Section 1 200 watts Maximum Long Term Average Midband Acoustic Output 82 watts Sensitivity SPL at one meter indicated input power anechoic environment band limited pink noise signal 1 Watt 99 5 dB 1 200 Watts 130 5 dB Beamwidth angle included by 6 dB down points on polar responses indicated one third octave bands of pink noise see Figures 3 and 4 80 to 160 Hz Horizontal 240 45 25 80 to 160 Hz Vertical 200 60 40 Directivity Factor R Q 63 to 100 Hz Median see Figure 5 2 20 0 38 0 34 Directivity Index 80 to 160 Hz Median see Figure 5 3 41 dB 0 70 dB 0 72 dB Distortion 0 1 Full Power Input see Figure 6 Second Harmonic 50 Hz 0 6 100 Hz 0 4 Third Harmonic 50 Hz 0 8 100 Hz 0 4 Transducer Complement Two EVX 180A Box Tuning Frequency 37 2 Impedance LF1 and LF2 paralleled see Figures 2 amp 7 Nominal 4 ohms Minimum 3 6 ohms Input Connections Neutrik Speakon NL4MPR Enclosure
4. cidental or consequential damages in cluding without limitation injury to persons or property or loss of use Some states do not allow the exclusion or limitation of incidental or consequential damages so the above limitation orexclusion may not apply to you Other Rights This warranty gives you specific nights and you may also have other rights which vary from state to state after re Electro Voice Speakers and Speaker Sys tems are guaranteed against malfunction due to defects in materials or workmanship for a panas of five 5 years from the date of origina purchase The Limited Warranty does to burned voice coils or malfunctions such as cone and or coil damage resulting from improp erly designed enclosures Electro Voice active electronics associated with the speaker sys tems are guaranteed for three 3 years from the date of original purchase Additional details are included in the Uniform Limited Warranty statement Electro Voice Flying Hardware including en ciosure mountec hardware and rigging acces sories is quaranteed against malfunction due to defects in materials or workmanship for a period of one 1 year from the date of original purchase Additional details are included in the Uniform Limited Warranty statement Electro Voice Accessories are guaranteed against malfunction due to defects in materials or workmanship for a period of one 1 year from the date of original purchase Additi
5. cy high frequency loudspeaker systems form the MT 2B full range system There two models in the MTL 2B series the MTL 2BCF carpeted finish with flying hardware and the MTL 2BC carpeted finish without flying hardware The MTL 2B is a vented box design comprised of two EVX 180A 18 inch woofers each facing into a manifold chamber at the center of the enclosure This manifolding technique U S Patent 4 733 743 results in increased acoustic loading yielding increased low ire quency efficiency and reduced distortion over conventional direct radiating designs in a re markably small enclosure MTL 2B is typi cally 2 3 dB more efficient than horn loaded enclosures of equivalent size in the 40 80 Hz range Additionally by having the motor struc ture on the outside of the enclosure this radical design allows for efficient heat transfer from the loudspeakers to minimize thermal build up dur ing extended periods of high power operation The EVX 180A was designed to deliver the highest possible low frequency output and is ideal for manifolding in the MTL 2B enclosure lts extended 4 inch diameter voice coil design assures linear low distortion output at extremely high power levels while its robust mechanical design is capable of withstanding the high acoustic pressures developed in the manifold chamber during explosive instantaneous power peaks MTL 2B SPECIFICATION GRAPHICS FIGURE 1 Frequency Respo
6. fficient assembly To facilitate service a variety of screws washers and hex key wrenches are provided with each loudspeaker system In addition there are wiring diagram labels in convenient locations inside the sure FREQUENCY RESPONSE MTL 2B frequency response shown in Figure 1 was measured both with and without equalization and crossover filters on axis in the farfield in an anechoic environment using a swept sine wave signal When measured with an electronics the Dx34 digital electronic unit was used to provide the necessary crossover filters and equalization With the crossover in place a high pass protection filter was applied to the low end of the low frequency section One watt of power 2 00 volts rms at 70 Hz was applied to the midband of the low frequency section The sound pressure level was normal ized for an equivalent one meter distance DIRECTIVITY The directional response of the MTL 2B was measured in an anechoic environment at a ee a ee distance of 6 1 meters 20 feet using 1 3 octave filtered pink noise A full spherical mea surementsystem was used The polarresponse of the loudspeaker system at selected 1 3 octave frequencies is shown in Figure 3 The frequencies selected are fully representative of the polar response of the system The beamwidth of the system utilizing the complete 1 3 octave polar data is shown in Figure 4 The Directivity Factor Q R and Directivi
7. ime delay polarity and gain ad justment the parameters of which all programmed and stored by the user In the Zero ODING erro rand time alignmen t between frequency bands In addition the out put levels of each frequency band are set so that with the output level controls set the zero dB position the loudspeaker system will have a flat frequency response in an anechoic envi ronmentwhen used with amplifiers having iden tical gain ELECTRICAL CONNECTION AND SYSTEM WIRING Electrical connections to the MTL 2B are made on the back of the enciosure via a 4 pin connec tor There are two connectors on the input panel to allow paralleling of other MTL 2B systems The Neutrik Speakon NL4MPR is used for both connections One mating Neutrik Spea kon NL4FC cable end connector is supplied with each loudspeaker system The pin assign ments are as follows Pin 1 LF1 Pin 2 LF 17 The MTL 2B has two 8 ohm woofers with one nnecied to Pins 1 1 and the other to Pins 2 2 2 2 A wiring diagram the system is shown Figure 7 The electrical mpedance versus frequency is shown in Fig FLYING THE MT SYSTEMS A manual entitled the MT available from Electro Voice and is included with each flying MT loudspeaker system A brief ntroductory overview is included here The MT Fiving Manual should be consulted for com plete structural specifications and detailed in forma
8. loudspeaker enclosure shall be 36 00 inches high 22 50 inches wide and 29 88 inches deep and shall weigh 174 pounds The loudspeaker system hall be the Electro Voice MTL 2B MTL 2BCF r MTL 2BC 4 Q UNIFORM LIMITED WARRANTY Electro Voice products are guaranteed against malfunction due to defects in materials work manship tor a specified period as noted in the ouble stud ring fittings In individual product line statement s below orin the individual product data sheet or owner s da ee e pe See u other than as specified in product data sheet or owners manual d malfunction re sulting from misuse or abuse of the product or e malfunc tion occurring at any time pairs have been made to the product by anyone other than Electro Voice or any of its authorized service representatives Obtaining Warranty Service To obtain warranty service a cus tomer must deliver the product prepaid to Electro Voice or any of its authorized service representatives together with proof of purchase of the product in the form of a bill of sale or Pet invoice list of authorized service representatives s available from Electro Voice at 600 Cecil Street Buchanan MI 49107 616 695 6831 or 800 234 6831 Incidental and Consequential Damages Excluded Product repair or replacement and retum to the cus tomer are the only remedies provided to the customer Electro Voice shall not be liable for any in
9. moving the grille using a 2 Phillips screw driver The woofers can be unbolted using a 5 32 inch hex key wrench and slid straight out of the manifoid chamber There is a wiring diagram label for the system located on the underside of the input panel As a further ser vice convenience a hardware kit that includes a 5 32 inch hex key and an assortment of spare screws and washers are included with every MTL 4B loudspeaker system woofer failure will require the entire driver to returned to an authorized Electro Voice ervice center for repair The following parts are available from the Electro Voice Service Department in Buchanan Michigan om 00 MTL 2B Service Data Sheet 53448 LF 818 2389 EVX 180A Driver ARCHITECTS AND ENGINEERS SPECIFICATIONS The loudspeaker system shall be low fre quency system and shall operate from 37 200 Hz with a sensitivity of 99 5 dB for one watt at one meter The system shall consist of two 18 inch woofers manifolded at the center of a vented box enclosure have a total input im pedance of 4 ohms and have a power rating of 1 200 watts as per ANSVEIA 426 A The loud Speaker system shall have an enciosure con structed from 0 75 inch thick 14 ply birch ply wood be finished with a black carpet ora black textured paint have a black nylon grille and have a two point rigging system that will accept Kinedyne 32102 1 of 32111 1 type double stud ring fittings if applicable The
10. nse ATT Can Te TT TE UT NE FIGURE 5 Directivity vs Frequency SPL dB FREQUENCY IN HERTZ 120 ze I TEE TI TITTEN ET LET TAT TT fi e A A T TE ee 1 EEE EHI Y BEIN FIGURE 2 vs Frequency IMPEDANCE 1 FREQUENCY IN HERTZ FIGURE 3 Polar Response 5 dB PER HORIZONT AL DIVISION VERTICAL FIGURE 4 Beamwidth vs Frequency j mE BEAMWIDTH IN DEGREES 648 PR RADA All versions of the MTL 2B are constructed of 0 75 inch thick 14 ply birch plywood and ex tremely well braced to survive the rigors of the road The MTL 2BCF flying and MTL 2BC systems are covered with black Ozite Super TNT carpeting the most rugged in the industry The MTL 2BCF system incorpo rates a unique two point flying system All mod els feature a black nylon cloth grille The RD 1 removable dolly is available for transporting the MTL 2BCF and MTL 2BC on their sides APPLICATIONS The MTL 2B is ideal for any professional con cert sound touring or permanent installation application requiring high sound pressure lev els at low frequencies with low distortion from a compact enclosure The Manifold Technology design maximizes the aco
11. onal details are included in the Uniform Limited Warranty Statement Service and repair address for this product Electro Voice Inc 600 Cecil Street Buchanan Michigan 49107 616 695 6831 or 800 234 6831 Specifications notice subject to change without company 600 Cecil Street Buchanan Michigan 49107 MANUFACTURING PLANTS AT E BUCHANAN E NEWPORT TN SEVIERVILLE TN OKLAHOMA CITY OK ME GANANOQUE ONT Electro Voice Inc 1995 thy n U S A Number 532448 9502
12. tion on safely suspending and using the Mi systems larmiaf FIYI 9 is 15 MTL 2BCF carpeted is the version of the MTL 2B loudspeaker system that includes fly ing hardware The MT systems incorporate a unique two point flying system that permits wide range of vertical angle adjustment and offers maximum flexibility in array design and plementation for both touring sound and per manent installations The quick release craft L track type hardware design allows ar rays loudspeakers to be assembled and disassembled very quickly and offers such fiexibility in the vertical angling of cabinets that pull up points are usually unnecessary Fur thermore all of the flying MT 2B and MT 4B loudspeaker models include the same rigging hardware allowing the different models to b mixed as necessary througnout an array a 4 ow ELECTRO VOICE omarxi The rigging track accepts Kinedyne 32102 1 and 32111 1 type el iri 12 r nm nm rra der AA en w flying hardware accessories for use with the MT loudspeaker systems CAUTION The MT loudspeaker systems should be suspended overhead only in ac cordance with the procedures and limita tions specified in the MT Flying Manuai and manual update notices FIELD SERVICE In the unlikely event that the MTL 2B should require service the 18 inch woofers can be accessed from the front of the enclosure by re
13. ty Index D are shown in Figure 5 Complete AcoustaCADD data is available for the MTL 28 loudspeaker system DISTORTION Distortion for the MTL 28 shown in Figure 6 was measured on axis in the farfield in an anechoic environment ata level of 0 1 times the full power rating 120 watts as per the AES standard The sound pressure level was nor malized for an equivalent one meter distance Plots of second and third harmonic distortion are shown referenced to the fundamental POWER HANDLING CAPACITY Electro Voice components and systems are manufactured to exacting standards to ensure reliability in continuous use in arduous real life conditions Besides utilizing industry standard power tests extreme in house power tests which push the performance boundaries of the loudspeakers are also performed for an extra measure of reliability The MT systems are rated as per the ANSI EIA 426 A Loudspeaker Power Rating Full Range Test which uses a shaped random noise signal to simulate typi cal music to test the mechanical and thermal capabilities of the loudspeakers Specifically the MTL 4B passes the ANSI EIA 426 A power test with the following test parameters LF Section LF1 amp LF2 paralleled EMAN 1 200 watts total Test Voltages 58 7 volts rms 117 4 volts peak Asa 1 15 x R 2 88 ohms each input SUBPASSBAND SPEAKER PROTECTION Below the enclosure tuning frequency cone excursion increases rapidly with little increase in
14. ustic output per en closure frontal area acoustic output per sure bulk volume and acoustic output per enclosure weight of the loudspeaker system This enables loudspeaker arrays to be con structed that are significantly smaller and lighter than would be obtainable with conventional loudspeaker system designs The MTL 2B may be combined with other members of the MT 2B and 4 loudspeaker family providing the array designer a variety of coverage angles acoustic output and enclosure sizes from which to choose For full range applications the MTL 2B may be combined with the MTH 2B or MTH 4B midbass mid frequency high frequency loudspeaker systems The MTH 2 94B sys tem has a rectangular enclosure that is dimen sionally identical to the MTL 2B For maximum acoustic performance of the MT loudspeaker systems the Electro Voice Dx34 digital elec tronic crossover equalization time delay imiter unit is recommended Careful attention was paid to details to provide both the touring company and sound contractor a convenient and timesaving sound reinforce ment package The MT 2B dimensions were chosen for efficient truck pack and high density array design The systems may be stacked four high and three wide or three high and four wide in a standard truck box enabling 12 000 watts of sound system to be accommodated only three feet of truck floor length The two point rigging system offers flexible array design and e
15. wo systems were widely spaced the maximum acoustic power output increase is limited to the 3 dB power handling increase Additional sound pressure level can also occur from the increased directivity that results when multiple systems are closely arrayed together if two systems are placed side by side the beamwidth of the combined systems at low frequencies will be approximately one half the beamwidth of a single system in the plane that they are arrayed Adding additional systems will reduce the beamwidth further at low fre quencies Systems can be arrayed both hori zontally and vertically to increase directionality in both planes LOUDSPEAKER LOCATION Low frequency loudspeaker systems such as the MTL 2B are often located on the floor or close to wails This is often convenient and provides additional acoustic loading toincrease the low frequency efficiency of the system Because there is typically little directional infor mation present in program material below 125 Hz the audible location of the low frequency loudspeaker system will not be particularly evi dent with the low frequency systems located on the floor separated from the higher frequency systems positioned overhead for the desired locational cues and uniform audience cover age Other situations however may benefit from having the low frequency systems suspended overhead along with the higher frequency sys tems Floor space may be limited or sightlines ma
16. y be a problem on the main floor seating area requiring low frequency systems to suspended overhead higher crossover fre quencies or program material with low frequency locational cues may require may require the low frequency systems to be located near the higher frequency systems or a particular geo metric layout of a venue and sound system may require low frequency systems to be suspended overhead for even coverage In theseinstances it may be possible to regain much of the effi ciency lost by removing the low frequency sys tems from the floor by closely spacing the systems to increase the mutual coupling and by constructing the low frequency array in a manner that increases the low frequency direc tivity CROSSOVER EQ AND TIME DELAY The usable frequency range of the MTL 2B low frequency loudspeaker system is 32 200 Hz A crossover frequency of 160 Hz with 24 dB per octave slopes is recommended For full range applications one of the MTH 2B midbass mid frequency high frequency loudspeaker systems is recommended for use with the MTL 2B For optimal acoustic performance the Electro Voice Dx34 digital electronic crossover equalization time delay unit is recommended The 34 is a programmable two in four out digital electronic unit which may be configured for stereo two way mono three way plus sub woofer or mono four way operation Each out put section includes crossover filters equaliza tion limiting t
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