ORBIS RELIABLE CONFERENCING

Transcription

1 ORBIS RELIABLE CONFERENCING CONFERENCE TECHNOLOGY MADE IN GERMANY DESIGN GUIDE Edition 1/2015 english

2 INTRODUCTION Since 1924, beyerdynamic has been researching, developing and selling new audio technologies. Our philosophy is to develop and manufacture first-class audio products. For us, the use of stateof-the-art technologies, as well as a high quality standard, have always been paramount. beyerdynamic systems are employed throughout the world for the benefit of communication. Our equipment can be used for meetings and conferences of any size, in town halls and hotels, banks or corporate conference rooms. beyerdynamic conference systems are easy to install and set up, and are therefore ready to operate at any time and any place. This Orbis Design Guide from beyerdynamic serves as a planning aid for beyerdynamic conference systems. It is aimed at architects, planners and installation companies. In addition to the general principles for wired digital communications technology, this document provides information about components, applications and cabling of the Orbis conference system. Do you have any questions or suggestions for the Orbis Design Guide? The beyerdynamic Conference Team will be pleased to help. Phone: +49 (0) / conference@beyerdynamic.de

3 CONTENTS 1. Basic principles Microphone types Dynamic microphones Electret condenser microphones True condenser microphones Polar pattern Revoluto a revolution in conference technology Basic principles Revoluto, an alternative to gooseneck microphones? Wired, digital conference system Orbis Components Application On the table In the table Under the table Audio Block Diagram Cables

4 Basic Principles 4 1. Basic principles 1.1 Microphone types Microphones are mainly differentiated according to their type i.e. the type of the electro acoustic transducer and polar pattern. Nowadays the following types are mainly in use: Dynamic microphones Dynamic microphones work on the principle of electro-magnetic induction. In dynamic microphones the speed of the diaphragm movements causes the signal, not the current deflection. This is the reason why a dynamic microphone is also referred to as a velocity microphone. Dynamic microphones are mainly used for live applications. TG V 50 d Ribbon microphone A ribbon microphone is another type of dynamic microphone. This microphone type closely combines the transducer type and acoustical function. The diaphragm of the ribbon microphone is a fanfold aluminium ribbon, which is 2 to 4 mm wide and some centimetres long. The ribbon has a thickness of only a few microns. In ribbon microphones, a current is induced at right angles to both the ribbon velocity and M 130 magnetic field direction. As the sound wave causes the ribbon to move, the induced current in the ribbon is proportional to the particle velocity in the sound wave. Ribbon microphones have an almost linear frequency response; their extremely light diaphragm provides good pulse behaviour. The ribbon is open to sound both front and back. Therefore, the acoustical principle corresponds to a pressure gradient microphone. This results in a figureeight polar pattern. Ribbon microphones are not suitable for miking very low frequencies. Moving coil microphone The moving coil microphone is a type of dynamic microphone. The name refers to the construction of the transducer: With moving coil microphones a small movable induction coil is attached to the diaphragm. When the diaphragm vibrates, the coil moves in the magnetic field, producing a varying current in the coil through electro-magnetic induction. These are the advantages of this microphone type: Relatively robust to mechanical stress High SPL capability (useful when singing or playing loud instruments) No supply voltage needed Relatively inexpensive Due to the coil mass, moving coil microphones provide a limited reproduction spectrum and poor pulse behaviour. They are suitable for close miking, because non-linear distortions are rare with high sound pressure levels. Dynamic microphones are widely used on-stage for live applications. Sound waves Diaphragm Permanent magnet Coil Signal Diagram of a moving coil microphone Permanent magnet Fanfold aluminium ribbon Sound waves Diagram of a ribbon microphone Signal Electret condenser microphones The electret condenser microphone is a type of condenser microphone. Between the plates of the capacitor is an electret film, which conserves the diaphragm bias. In the microphone capsule there is a preamplifier to amplify the weak signal streams. The needed voltage is volts and therefore less compared to true condenser microphones. The power requirement is < 1 ma and makes these microphones ideal for the use with mobile devices (e.g. beltpack transmitters). With a market share of 90% the electret microphones are the most commonly used microphones throughout the world. Electret condenser microphones are produced in large quantities because of their extremely compact construction, the low price and the audio quality, which is sufficient for many applications. These microphones are found in almost every advanced voice communication tool (e.g. headsets, mobile phones, hearing aids etc.). The size of the microphone capsule is mostly between one millimetre and one centimetre. Good electret condenser microphones provide a frequency response between 20 Hz and 20 khz as pressure microphones (omnidirectional microphones). Electret condenser microphones are not suitable for high amplitudes, because in this case they produce non-linear distortions. Classis GM 31x

5 Basic Principles True condenser microphones The true condenser microphones operate according to the physical principles of capacitors. As the diaphragm displacement produces the signal and not the diaphragm speed, condenser microphones are also referred to as elongation receivers. Condenser microphones are available in most different designs, as this term only designates the transducer principle. The term, however, has been established as a microphone category, because the sound properties are closely connected with the transducer principle. MC Polar pattern The polar pattern of a microphone indicates how sensitive it is to sound arriving at different angles about its central axis. Normally the polar pattern is shown with a logarithmical scaling. You can differentiate between the proportions in the direct and diffuse field. The polar pattern depends on the design of the microphone capsule and the exterior (e.g. shotgun microphone). The strength of the directivity is described with the sound power concentration. An omnidirectional microphone absorbs the sound pressure from all directions. The directivity is designated by characteristical patterns: Omnidirectional (undirected) Figure-eight (dipole = opposing polarity on the front and rear) Lobe (shotgun) and others such as with Revoluto Principle In a condenser microphone there is a thin diaphragm in front of an insulated metal plate. A potential gradient is ensued between the diaphragm and plate when an electrical voltage is applied. This assembly corresponds to a plate capacitor, which has an electrical capacity. When sound makes the diaphragm vibrate, the distances between the two capacitor plates and the capacity of the capacitors change. These variations in capacitance effect variations in voltage an electrical signal. A voltage source is needed to achieve the potential gradient between the capacitor plates and to supply the impedance converter. Normally, the 48 volt phantom power of the preamplifier or mixing console is used. Omnidirectional Figure-eight Diaphragm Backplate electrode Sound waves Signal High-impedance resistance Voltage supply Lobe Diagram of a condenser microphone MC 840 Condenser microphone

6 Basic Principles 6 Mixed forms are: Cardioid (mixture between omnidirectional and figure-eight) Wide cardioid Supercardioid Hypercardioid The higher the directivity, the higher may be the distance between sound source and microphone without changing the proportion of the diffuse sound to the direct sound. Omni Cardioid Supercardioid Hypercardioid Figureeight Distance Wide cardioid Supercardioid Cardioid Hypercardioid The polar pattern strongly depends on frequencies and is normally stated in data sheets from a frequency of 1 khz. Furthermore, the sensitivity decreases with higher frequencies. In addition to the angle of radiation, the polar pattern states more parameters such as the directivity factor, the guiding dimension and the sound power concentration. The polar pattern of microphones is measured in the direct field D in anechoic chambers, even when the lobe polar pattern of a shotgun microphone is only used in the room field R or diffuse field. In the diffuse field each directional microphone loses is bundling polar pattern. This means: The efficiency of the sound focusing polar patterns is only valid within the reverberant radius; outside this radius the directivity decreases with increasing distance to the sound source. The directivity only depends on the acoustical construction of the capsule not on the transducer type. A pressure microphone has no directivity, i.e. the polar pattern is omnidirectional. A pressure-gradient microphone (e.g. ribbon microphone) provides a figure-eight polar pattern. Special constructions of the capsule or the electrical mixture of the signals of two neighbouring capsules provide polar patterns between omnidirectional and figure-eight. Standardised intermediate forms between omnidirectional and figureeight polar pattern are wide cardioid, cardioid, supercardioid and hypercardioid. The lobe polar pattern is typical for an interference tube (shotgun microphone; sound-direction dependent cancellations due to acoustical efficient propagation time). On the front, the lobe polar pattern accepts only higher frequencies in a very narrow area. This polar pattern strongly depends on frequencies. On the rear, the pickup capacity is reduced and diffuse, i.e. indefinite. Due to the complex conditions of the sound field, the real polar pattern individually differs from these theoretical patterns. Strong deviations of the patterns are present, when the wavelength of the signal frequency moves in the area of the capsule diameter. Therefore, these distortions are the less, the smaller the diameter of the diaphragm. The most frequent deviations are found with pressure-gradient microphones whose polar pattern has been modified from a pure figure-eight to cardioid. Pressure microphones provide directivity with high frequencies due to the pressure build-up and the sound shadow caused by the microphone body. In conference applications microphones with cardioid polar pattern are predominantly used. The maximum cancellation is at 180, i.e. directly from behind. From the front, the pickup range is wide so that little movements of the speaker do not affect the sound or volume.

7 Revoluto Technology Revoluto a revolution in conference technology Basic principles First things first: the new Revoluto microphone unit does not just mean that gooseneck microphones disappear from conference microphone units, but also that feedback susceptibility is decreased and S/N ratio improved in comparison with the gooseneck microphone. All this, despite the fact that the unit is positioned up to 80 cm away from the speaker on the far side of the table. A revolution indeed! In the last few years, innovation in conference technology has mostly taken place in the field of signal processing and transmission, one example being the changeover to a fully digital world. This, however, does not mean that there is no more potential to be discovered in the acoustic realm. And Revoluto is impressive proof of this. Most people would agree that forests of gooseneck or foldaway stem microphones on conference tables are not exactly easy on the eye. Camera technicians have repeatedly called for the situation to be remedied. Furthermore, such set-ups are often a source of annoyance for the equipment providers, as visitors often play around with the microphones, resulting in damage. Gooseneck and stem microphones (with foldaway, rotating or other designs) feature directivity capsules, almost exclusively with cardioid characteristics. These are operated in close proximity to the sound source. The reason for this is the high ratio of direct sound (the speaker) to indirect sound (from the loudspeakers) necessary for a sufficiently loud audio transmission with the help of loudspeakers in the same room. Only in this way can feedback be avoided to a large extent. In a normal arrangement of conference microphones, playback speakers are provided at all units, providing what is known as a distributed sound system. In comparison to the playback produced by ceiling loudspeakers or central loudspeaker arrangements, these have the great advantage that each participant is sitting within the so-called reverberation radius of the nearest loudspeaker. Reverberation radius refers to the distance from the sound source (here, the loudspeaker), where the amount of sound directly received is exactly the same as the amount of sound received by reflection. This ratio is of crucial importance for speech intelligibility. When one considers the physical background to the task, which boils down to an increase in distance, one will first of all logically come across the inverse-square law, according to which the sound pressure level drops as the distance from the sound source increases. An immediate consequence of this is that if it were possible to increase the distance, the dependence of the transmission volume on the speech distance would also be reduced, as the signal would then be located on the flatter part of the characteristic curve. This is therefore a worthwhile goal, when we consider that speakers either feel compelled to move around or consistently ignore the microphone, often to the outrage of sound technicians and interpreters. Although interference shotgun microphones do focus the sound, they also have the disadvantage that the shotgun polar pattern is very narrow, causing any sideways or vertical movement on the part of the speaker to create a drastic drop in level. Additionally, even with a short shotgun attached, such microphones extend too far towards the sound source due to their sheer size. Once it was established that the ratio of direct to indirect sound is the deciding factor for conference applications, work began on designs that would eliminate indirect sound even further, thus pushing the ratio towards a greater amount of direct sound (see, for example, the cardioid level microphone, where a vertical microphone column narrows the shotgun polar pattern vertically, much like the well-known column loudspeakers). Another example is beam forming using microphone arrays. The latter is only really conceivable for special applications, but it is not suitable for conference purposes. The cardioid level microphone, with its vertical rejection, aims at masking the sound components arriving from ceiling speakers or those reflected by ceiling and floor and originating from the playback loudspeakers in the room, while the horizontal shotgun polar pattern should be as wide as possible to give the speaker freedom to move. Beam-forming methods with arrays fixed on one level mostly process longitudinal sound waves, in other words those from sources infinitely far away. This is not the case in conference use. What is more, such an arrangement is far too big and cumbersome to be implemented. In order to move closer to a solution which allows the microphone to be moved considerably further from the source, the changes to be made at the same time must result in the energy received from undesired sound sources (neighbouring units, indirect sound) increasing less significantly than the direct sound energy received from the sound source. Otherwise the distance cannot be increased. It must also be ensured that loop gain does not increase, as the feedback limit would otherwise inevitably be exceeded. To put it a different way: if the speech distance is increased, the correspondingly adjusted pick-up equipment must compensate for the loss in level to which the signal is subject, according to the inversesquare law, on its way from the sound source to the equipment, without increasing the sound received from other directions. At first, this seems contradictory and therefore not feasible. Revoluto solves this problem with a special arrangement of the capsules and provides an excellent concentration on the sound source; the pickup pattern corresponds to a 30 cm wide corridor. Compared to an individual microphone capsule, the dependence of the volume is clearly lower so that the speech distance can vary between 30 cm and 2 m (depending on the installation and surroundings). The optimal speech distance is between 60 and 80 cm. Furthermore, the probability of popping noise is nil when close miking. Patents protect the design and technology of Revoluto. If, however, you simply increase the distance, by integrating the capsule into the microphone unit, for example, the ratio of direct to indirect sound quickly worsens, leading to immediate feedback from the loudspeakers also located in the room as soon as any attempt is made to restore the desired volume by increasing gain. A typical speech distance for a conference microphone is cm. With an increase in distance to 80 cm (ideal position on the far side of the table), this is more than tripled, which means a level loss of over 10 db. With a loss of 10 db, a conventional conference unit is made completely redundant. It is simply not practical.

8 Revoluto Technology 8 Polar pattern of a Revoluto microphone Vive la revolution! This is one of the reasons why the Revoluto microphone units have such excellent protection from feedback in conference applications. Compared to other set-ups with conventional individual microphones, the level of protection is at least 4 db, and typically even 6 db greater even with person-to-mic distances of up to 80 cm. Moreover, the microphone unit can be placed on the opposite side of the table, leaving enough space for documents. In spite of the large person-to-mic distance, optimal speech intelligibility is attained, as are very good useful sound pressure levels (gain before feedback Revoluto, an alternative to gooseneck microphones? Compared to gooseneck microphones, Revoluto provides many advantages: Better visual impression of the speaker Sound and volume are relatively independent of the speech distance Clear separation between neighbouring speakers No popping or plosive noise Little space required on the table (suitable even for small desks) Of course Revoluto is not a universal tool. Especially in rooms with reverberant walls where strong reflexions from the speaker hit the microphone, standard gooseneck microphones achieve better results. This refers especially for reverberation rooms (rooms with a long reverberation time of 1 second). If in doubt, it has to be tested with a kind of sound check, whether Revoluto meets the requirements. Nobody can do magic As with every new piece of innovative technology, there are some limitations that come along with the outstanding advantages. In the case of Revoluto, it depends on the application. Microphone units using Revoluto technology lack the intelligence to determine whether the signal is being picked up from the person speaking or from sound waves bouncing off a wall behind that person. In the case of the latter, there are unwanted reflections, which could lead to worse intelligibility, especially in rooms with echoes. In addition, attaining sufficient volume in a conference room is possible only with difficulties due to the increased tendency towards feedback (see gain before feedback). Seldom, there may be a comb filter effect, in spite of filters, with extremely reflective table surfaces. The sound waves reach the microphone capsule both directly and indirectly via the reflection from the table's surface. Both sound waves overlap and can lead to cancellation at different frequencies.

9 Revoluto Technology 9 Yet another aspect of physics makes Revoluto technology truly suitable for practical applications: with a speaker-to-mic distance ranging from 30 cm to 80 cm, the volume varies only by a max. of 3 db. The active conference participants can lean forward, lean back to relax or even stand up. Optimal intelligibility, constant voice tone quality and a constant and very good sound pressure level revolutionary! Revoluto optimal voice range

10 Orbis 10 Microphone Positioning When notebooks are being used, it is also necessary to consider the microphones. Notebooks should always be positioned to the side of the microphones. Otherwise, when opened, the LCD screen would obstruct the sound. This also applies to free- standing monitors. Sufficient distance is the key to the directional effect and good feedback suppression. Moreover, notebooks often have fans at the back. The noise of the fan would then be picked up by the microphone. 2. Wired, digital Conference System 2.1 Orbis Reliable, intuitive, functional this is Orbis, the new digital wired conference system. The product family consists of several components: Accessible desktop or built-in microphone units with a loudspeaker and a detachable gooseneck microphone as well as a control unit with an innovative operating concept - easy to install or freestanding. The new conference system combines design and the discreet integration into high-quality furniture with reliability and ease of use. Due to numerous customisation options the microphone units can be adapted to customer requirements. The housings are available in different colours and the plastic plates leave complete freedom regarding the design: logos can be integrated, the colour and the material can also be changed. Two Revoluto microphones should not be directly placed back to back, because the loudspeaker of the second built-in or desktop microphone unit will be picked up by the microphone and cause feedback. The minimum distance should be 15 to 20 cm cm 15 cm In order to avoid feedback, the minimum distance between external loudspeakers and the Revoluto microphone should be 5 m. 5 m For more information about application examples, please refer to the beyerdynamic Revoluto Design Guide.

11 Orbis Components Orbis System Overview

12 Application Application The Orbis product family provides different options of application, which will be presented in the following. A maximum of 100 microphone units can be connected in two lines to the Orbis CU control unit (2 x 50). For maximum reliablility the system can be connected in a ring to the control unit. With redundant operation, a maximum of 50 microphone units can be operated with one Orbis CU control unit. Connection of the Orbis MU21/23 microphone units in a ring Orbis CU control unit On the table For on the table applications the Orbis MU 21/23 microphone units are used. This is the simplest and most common method, which is often used in mobile applications. Connection of the Orbis MU21/23 microphone units in a daisy chain Orbis CU control unit max. 50 microphone units in a ring max. 50 microphone units in line 1 max. 50 microphone units in line 2

13 Application In the table For flush-mount installations the Orbis MU 41 and Orbis MU 43 microphone units are available. These types of microphone units have no loudspeaker, but the optional CA OL loudspeaker module is available. Connection of the Orbis MU41/43 built-in microphone units in a ring Orbis CU control unit Connection of the Orbis MU41/43 built-in microphone units in a daisy chain Orbis CU control unit max. 50 microphone units in line 1 max. 50 microphone units in line 2 max. 50 microphone units in a ring

14 Application Under the table The under the table application is the most discreet variant. For this the Orbis SU 63 system unit is used, which can be programmed as delegate or chairman microphone unit. It can mounted under the table or integrated upright into an armrest. It can be used with a gooseneck microphone of the Classis microphone series, installation mounting (ZSH 50 or GMS 52) and button (CA OP 2, CA OP 2 C, CA OP 2 F). Connection of Orbis SU 63 system units in a daisy chain Connection of Orbis SU 63 system units in a ring Orbis CU control unit Orbis CU control unit max. 50 system units in line 1 max. 50 system units in line 2 max. 50 system units in a ring

15 Application 15 Orbis SU 63 wiring diagram Example: 5-pin XLR socket

16 Audio Block Diagram Audio Block Diagram The microphone signals of the microphone units are individually transmitted via the Orbis bus to the control unit. Inside the control unit the microphone signals are mixed and transmitted to the different outputs. Depending on the setting on the control unit, the signal from the Aux In input is also mixed. The audio signal for the SD card recorder can be configured via the serial interface. Microphone Unit Speaker Mic Volume Microphone Unit Microphone Aux In Loudspeaker Max. NOM = 8 Speaker Headphone Aux In Channel Selector Aux In Audio Out Mic Aux In Balanced Output Unbalanced Output Mic Aux In SD-Card Recorder Control Unit RS 232 controlled

17 Cable Cables CA OC Orbis cable For Orbis the worldwide standard of Cat5e network cables with RJ45 connectors is also used. The pin assignment is according to the EIA/TIA T568B standard. Both connectors have the same pin assignment which results in an 1 : 1 (even) cabling for all cables used for the Orbis system. Cable: The cable corresponds to the CAT5e category Type: F/UTP (overall shield as foil shield, wire pairs unshielded) External diameter: 6 mm Cross section: AWG24/7 (wire 7xAWG32) Connector: As connector a shielded RJ45 connector is used. Note: The more microphone units are operated in one line, the more important is a large cross section of the cable, as the power supply is also effected via the wires of the cable. This is the reason why all beyerdynamic CA OC cables for Orbis base on AWG24 cables. CA OC Orbis cable Pin assignment The Orbis CA OC cables are wired according to the TIA-568B standard and the CA OC connector is shielded. An 1:1 cabling (even) is easy to recognise if you put both connectors next to each other and compare the sequence of the wires. If both connectors have the same assignment, then it is an 1 : 1 cabling. 1 : 1 cabling Pin assignment

18 Cable 18 Background Information on Network Cables In daily use the cables are referred to as Cat cables. These cables are mainly used for telecommunication or computer technology. A network cable is set up by wire pairs which are twisted (twisted pair). The data signals are transmitted via these wire pairs in a balanced form. Twisted balanced pairs have the advantage that electromagnetic interferences from the outside are almost completely cancelled out. The network cables are mainly distinguished according to the performance (category) and their structure (type of the shielding). Division in categories The most important distinguishing feature is the maximum operating frequency of the cable. The higher the category, the higher is the maximum transmission frequency of the cable. More important parameters are the impedance of the cable, the attenuation and the crosstalk within the cable. EIA/TIA 568 ISO/IEC EN max. Impedance Application Cat khz 100 ohms analogue voice transmission - - Class A 100 khz 100 ohms analogue voice transmission Cat. 2 - Class B 1 MHz 100 ohms ISDN Cat. 3 - Class C 16 MHz 100 ohms 10Base-T, 100Base-T4, ISDN Cat MHz 100 ohms 16 MBit Token Ring Cat. 5 Cat. 5 Class D 100 MHz 100 ohms 100Base-TX, SONET Cat. 5e Cat. 5e Class D 100 MHz 100 ohms 1GBase-T Cat. 6 Cat. 6 Class E 250 MHz 100 ohms 1GBase-T, 155 MBit-ATM, 622-MBit Cat. 6A Cat. 6 A Class E A 500 MHz 100 ohms 10GBase-T - Cat. 7 Class F 600 MHz 100 ohms 10GBase-T (bis 100 Meter) - Cat. 7 A Class F A 1000 MHz 100 ohms 10GBase-T, 40GBase-T4 and 100GBase-T Shielding In addition to the division into class and categories you refer to the composition of coating, shield and wire pairs when speaking about twisted pair cables. Basically you distinguish between shielded and unshielded cables. In contrast to the shielded cables (STP and FTP) the unshielded cables (UTP) have a significantly poorer quality of transmission which has a negative effect at high transfer rates and long cable lengths.

19 Cable 19 Nomenclature With the ISO/IEC-11801, a designation system in the format XX/YZZ was introduced. It is: XX for the overall shielding: U F S SF unshielded foil shield braided shield braided and foil shield Y stands for the wire pair shielding: U unshielded F foil shield S braided shield F/UTP cable, used in the Orbis system ZZ stands for the type of stranding: TP Twisted Pair QP Quad Pair Twisted Pair cable (TP) U/UTP F/UTP S/UTP U/FTP S/FTP F/FTP SF/FTP Overall shielding Wire pair shielding Wire mesh X X X Foil (F) X X X Wire mesh Foil (F) X X X X Wire cross section The wire pairs in the cables are either rigid wires or flexible wires. The cross section is often stated as AWG (American Wire Gauge). The smaller the number the larger is the cross section of the wires. AWG table for single-wire conductors AWG Diameter [mm] Cross section [mm 2 ]

20 Cable 20 Flexible cables are made of single wires. In the following there are two examples for the popular AWG26 and AWG24 cables. Size AWG Maximum cable lengths The maximum length is limited by the influence of line effects on the signals, such as cable attenuation, crosstalk, noise etc. So that with the maximum number of 50 microphone units per line long enough cables can be used, the signals are regenerated in each microphone units. Single wires Number x AWG 7x34 10x36 19x38 7x32 10x34 19x36 41x40 Control unit to the first microphone unit: 80 metres Cable between microphone units: 80 metres These maximum lengths cannot be increased by a larger cross section. Descriptions for single and stranded conductors single wire: e.g. AWG 26/1 or AWG 24/1 stranded: e.g. AWG 26/7 or AWG 24/7 RJ45 connector The RJ45 connector is also widespread and has been standardised in the 1970s. In English the letters RJ stand for Registered Jack, which means standardised socket. Note: There are different connectors for single wire and stranded cables. Pin assignment according to EIA/TIA 568A/B The pin assignment of the RJ45 connector has been standardised by the Electronic Industries Alliance (EIA) and Telecommunications Industry Association (TIA) organisations. Two different but common contactings were considered. The only difference between TIA-568A and TIA-568B is the interchange of the pairs 2 and 3 (orange and green). Both standards wire the contacts straight through. This means that the contact 1 on one side is connected with contact 1 on the other side which is maintained with all eight contacts. Whether the cables are issued according to TIA-568A or TIA-568B does not matter, because they are wired 1 : 1. System wiring With the following tables and diagrams you can check a system design for maintaining all cabling rules. Basing on the frequently used AWG26 and AWG24 cables (original Orbis system cable) you can find out the maximum possible cable length by using the tables and diagrams. All details refer to the Orbis MU21, MU23, MU41, MU43, SU63 microphone units. In the calculations the contact resistance on the connectors and sockets as well as the aging are considered. System cable AWG 24 AWG 24 Initial length CU to MU Number of microphone units Length MU to MU System Wiring General limits for the Orbis cabling The cables used in the system digitally transfer all control and audio signals to and from the control unit and are used to power all microphone units. With the system wiring or the verification of a design it has to be tested if the power supply of all microphone units is ensured. Cross section The cross section of the cables decisively determines the voltage drop on the cables and limits the maximum number of microphone units which are powered via one line. It has to be considered that the minimum cross section must not be less than AWG26 (AWG28, AWG30, etc.) because of the internal overcurrent disconnection , ,5 12, , , ,5 2,5 1, ,5 0 0 The table displays how long the cables between the microphone units may be. As the cable length also depends on the initial cable length (from the control unit to the first microphone unit), you will find details to different initial lengths in the columns.

21 Cable 21 Orbis CU MU/SU MU/SU MU/SU MU/SU initial cable The initial lengths of 10, 20, 50 metres refer to our standard lengths in catalogues, 80 metres is the maximum possible length of a cable. The two lines of the control unit should be considered independently. Both lines must be checked individually whether the limits are adhered to. In the redundant mode (ring configuration) it must be checked for both directions if the limits are adhered to in a worst case scenario (interruption directly on the control unit). The following diagrams display the connection from the table graphically. Diagrams Maximum AWG 24 cable length for Orbis Cable length between MU to MU m CU to first MU 20m CU to first MU 50m CU to first MU 80m CU to first MU Number of MU's

22 Cable Detailed section of maximum AWG24 cable length for Orbis Cable length between MU to MU m CU to MU 20m CU to MU 50m CU to MU 80m CU to MU Number of MU's

23 Cable 23 System cable AWG 26 For cables with a cross section of AWG26 apply the same information as for AWG24 cables. AWG 26 Initial length CU to MU Number of microphone units Length MU to MU Maximum AWG 26 cable length for Orbis Cable length between MU to MU m CU to first MU 20m CU to first MU 50m CU to first MU 80m CU to first MU Number of MU's

24 Cable Detailed section of maximum AWG26 cable length for Orbis 9 8 Cable length between MU to MU m CU to MU 20m CU to MU 50m CU to MU 80m CU to MU Number of MU's

25 Notes 25

26 E1/C Orbis Design Guide (07.15) beyerdynamic GmbH & Co. KG Theresienstr Heilbronn Germany Tel. +49 (0) 7131 / Fax +49 (0) 7131 / info@beyerdynamic.de For further distributors worldwide, please go to Non-contractual illustrations. Contents subject to change without notice.