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CBT36K Assembly Manual 

PREFACE: 

This is the assembly/instruction manual for the CBT36K, a DIY kit-version 
of the CBT36 system,  a floor-standing CBT circular-arc high-end 
loudspeaker  line  array.  The  system  is  sold  as  a  do-it-yourself 
(DIY) loudspeaker kit by 

Dayton  Audio

. The system is also available as 

a  completed  unit.  The  CBT36  is  a  floor-standing  5  ft.  tall  two-way 
curved line array that provides sonic accuracy, low distortion, and sound 
field coverage control surpassing even the finest high-end loudspeakers.  

One  additional  amazing  feature  of  the  CBT36  is  that  it  is  time  aligned 
and linear phase not only at a “magic listening spot” in front of the array 
but  at  locations  on  the  floor,  to  locations  above  the  array,  and 
locations at extreme off-axis horizontal angles! 

The  CBT36  is  based  upon  declassified  military  research  on 
uniform-coverage  underwater  sound  transducers  originated  by  the  US 
Navy  in  the  late  70s  and  early  80s.  CBT,  which  stands  for 

C

onstant 

B

eamwidth 

T

ransducer,  is  a  term  coined  by  the  military 

researchers  in  their  technical  papers.  The  system  is  designed  by 
Marshall  Kay and Don Keele

.

 

Each array features 18 Dayton Audio 3.5" ND Series drivers along with 
72 specially  designed  1/2"  aluminum  dome  tweeters,  and  is  available 
in  kit  form  as  well  as  a  fully  assembled  product.  The  CBT36  will 
redefine your expectations of audio reproduction system performance! 

Page 

2

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Содержание Epique CBT36K

Страница 1: ...CBT36K Assembly Manual Constant Beamwidth Transducer System Signature Series...

Страница 2: ...phase not only at a magic listening spot in front of the array but at locations on the floor to locations above the array and locations at extreme off axis horizontal angles The CBT36 is based upon de...

Страница 3: ...INSULATION 24 5 6 ATTACH WIRES TO RESISTORS 24 25 5 7 ATTACH LEAD WIRES TO SPEAKON CONNECTOR 25 6 MOUNT DRIVERS ON FRONT PANEL 26 32 6 1 PREPARE PAINTED FRONT PANELS FOR DRIVERS 26 27 28 6 2 PARTS AND...

Страница 4: ...ROSSOVER SETUP 58 70 12 1 SETUP OF BEHRINGER DCX2496 ULTRADRIVE PRO DSP CROSSOVER 58 67 12 2 CONNECT THE BEHRINGER DCX2496 CROSSOVER TO THE SYSTEM 68 12 3 CROSSOVER FILTER EQ SETTINGS TABLE 69 70 13 S...

Страница 5: ...nual describes the assembly process of the CBT36K curved arc high end loudspeaker array sold by electronic supplier Parts Express It includes many sections to aid in the assembly procedure Two appendi...

Страница 6: ...repare the resistors 8 Prepare the connecting wires 9 Mount mid bass drivers and tweeter PC board modules to front panel 10 Wire mid bass drivers and tweeter PC board modules 11 Test polarity and shad...

Страница 7: ...ing line level connections and speaker cable connections to power amps 17 Power up for the first time and make sure it works 18 DONE Whew Enjoy 1 3 WORK AREA Find a comfortable well lit place to assem...

Страница 8: ...items 2 1 1 Tools 1 Wire stripper 2 Wire cutters 3 Needle nose pliers 4 4mm or 5 32 Allen Hex tool 5 2 Phillips screw driver 6 Ratchet with adapter for a Phillips screw driver 7 Sharpie felt tip pen...

Страница 9: ...t and is easy to use It will generate continuous sine square signals plus log linear stepped continuous sweeps from arbitrary start stop frequencies 2 2 3 Speaker Connector Cable and Wiring Options 2...

Страница 10: ...ts express com dayton audio dta 120 class t mini amplifier 60 wpc 300 3800 2 2 4 2 Dayton Audio APA150 150W Power Amplifier http www parts express com dayton audio apa150 150w power amplifier 300 812...

Страница 11: ...mponent test system 390 806 2 2 7 Measurement Microphone Options These are optional advanced measurement tools 2 2 7 1 Behringer ECM8000 Measurement Microphone http www parts express com behringer ecm...

Страница 12: ...anel to the enclosure 20 per enclosure NOTE These screws are not supplied separately The come with the un finished cabinet assembly and attach the front panel to the cabinet The front panel will be re...

Страница 13: ...connectors and wiring is found at http www n4tze com speakonconnectorwiring pdf 11 2 3 1 2 15 Resistor Non Inductive Wire Wound 1 0 Ohm Mills brand 12W 1 Tolerance 12 10 3 1 2 16 Resistor Non Inducti...

Страница 14: ...Bass wiring 17 36 3 1 2 21 Tweeter Module Assembly Four tweeters mounted on PC board Dayton Audio model ND13TG 8 The 3 4 diameter wide range tweeters are made by Dayton Audio and feature a 0 5 edge dr...

Страница 15: ...RED Stranded 25 ft spool tinned copper conductor Consolidated brand For tweeter wiring 26 1 3 1 2 30 Hook Up Wire 24 AWG YELLOW Stranded 25 ft spool tinned copper conductor Consolidated brand For twee...

Страница 16: ...ing all 20 of the 20 x 1 5 inch machine screws using the Allen tool specified above and set it aside for the moment If you are new to finishing it is best to finish your kit in groups For instance sta...

Страница 17: ...he Parts Express catalog is General Motors Paint Code 3986 called medium garnet red See Ditzler PPG http paintref com cgi bin paintdetail cgi ppg 3986 http paintref com cgi bin colorcodedisplay cgi di...

Страница 18: ...d drivers are completely quiet 5 1 2 Check ND91 Voice Coil Polarity 5 1 2 1 Connect test leads Connect test leads to the ND91 RED clip to the terminal and BLACK clip to the terminal 5 1 2 2 Connect th...

Страница 19: ...ding from the measurements for each driver You may also use the Parts Express WT3 to measure the impedance This reading is very sensitive to noise and vibration Make this measurement in a quiet area 5...

Страница 20: ...esistors in parallel as follows 1 5 Ohm and 5 Ohm two pairs 2 3 Ohm and 3 Ohm two pairs 3 2 Ohm and 2 Ohm two pairs 4 1 5 Ohm and 1 5 Ohm two pairs 5 2 6 Bent Lead Parallel Resistor Configurations Thi...

Страница 21: ...r wires have to be connected to the same terminal All wire is either 18AWG or 24 AWG stranded See instructions in next two sections The short section following the tables recaps the preparation of the...

Страница 22: ...n in the following table Note the listed quantities in this and the following tables are for a pair of CBT36s Notes for the 18 AWG wire table For wire ends that need to be Tinned heat the wire with an...

Страница 23: ...te Item 18 is below in the 24 AWG Solid Wire Table Notes for the 24 AWG wire table For wire ends that need to be Tinned heat the wire with an 800 degree soldering iron and apply just enough solder so...

Страница 24: ...ibe attachment of wires to the shading resistors Note Two sets of each of the following resistor combinations must be prepared for the left and right pair of CBT36s 5 6 1 Locate Parallel Resistors Loc...

Страница 25: ...remember to use the end of the wire with 3 4 of insulation removed Attach Long Lead Wires to Resistors Locate the remaining single resistors and connect wires as follows NOTE You should have two comp...

Страница 26: ...THAT THE DRIVER LOADING AND CONNECTING ALL THESE WIRES TO THE DRIVERS WILL GO QUICKLY AND YOU WILL SOON BE LISTENING TO YOUR NEW SPEAKER 6 1 PREPARE PAINTED FRONT PANELS FOR DRIVERS Orient panels face...

Страница 27: ...THIS MIRRORED ARRANGEMENT WILL ENSURE THAT THE WIRE ROUTES POSITION THE INPUT AT THE BOTTOM OF THE PANELS 6 1 2 Number each Driver Position Using Fig 7 as a reference number each driver position and...

Страница 28: ...refully on the following pages and you won t make a mistake 6 2 PARTS AND TOOLS FOR DRIVER INSTALLATION Parts and tools needed for driver installation This photo shows a layout of the front panels alo...

Страница 29: ...e on Front Panel Carefully position the tweeter modules on the panel Be sure to check the location of the red terminal for proper orientation 6 3 4 Tweeter Module Terminal Orientation The tweeter term...

Страница 30: ...t Panel Install all tweeter modules using the 6 32 x 5 16 screws Material List item 7 Do not over tighten because the MDF material will strip out easily If you do strip a hole this is easily repaired...

Страница 31: ...a un used gasket attached to its rear 6 4 2 Install Mid Bass Drivers on Front Panel Install all the ND91 mid bass drivers with the supplied 6 32 x 5 16 screws Material List item 7 Again avoid over tig...

Страница 32: ...ape over the holes This will be removed later Brush a small amount of nail polish on each screw head where it contacts the driver PCB For an example of the nail polish being applied to a screw see pho...

Страница 33: ...h to the speakers 7 1 1 Mid Bass Driver Symbol The following speaker symbol represents the ND91 8 mid bass driver 7 1 2 Mid Bass Schematic The following diagram shows the schematic of the mid bass sha...

Страница 34: ...n each panel At this point you don t need to wrap the wire around the terminal just stick it through the terminal and leave it straight This is clearly shown in the next photo in the Bank 1 Wiring Dia...

Страница 35: ...o minimize stray strands insert the wire into each terminal and leave the wire straight After all wires have been inserted then go back and wrap them around the driver terminals 7 2 1 2 After all Mid...

Страница 36: ...round Terminal on Mid Bass Driver View of red wire wrapped around the terminal of the ND91 7 2 1 4 Procedure to Hook Three Wires to Mid Bass Terminal Only two wires will fit in the ND91 terminal At lo...

Страница 37: ...ck to Bank 3 7 8 9 10 6 Gray 24 Black 17 Red 6 Gray 6 Gray Bank 2 Wiring Diagram Bank 2 input 4 Red 27 Red to Bank 5 1 5 1 5 ohm Note 1 5 1 5 is notation for two resistors in parallel The actual value...

Страница 38: ...shown in the photo until all soldering is complete NOTE The dangling resistors in the above and the following photo will later be attached to the backs of the drivers with adhesive 7 2 4 Banks 4 and 5...

Страница 39: ...f Mid Bass Bank 4 and 5 Drivers with all Connections in Place View of mid bass drivers in banks 4 and 5 after wiring After all wiring is installed and you have verified resistors are in the correct lo...

Страница 40: ...TWEETER MODULE SHADING NETWORK SCHEMATIC In this and the following sections both the tweeter schematic and tweeter wiring diagrams are shown 7 3 1 Tweeter Module Symbol The following symbol represents...

Страница 41: ...T36 tweeter shading network schematic The dashed lines are U jumpers or resistor leads soldered to the PC board 7 4 TWEETER MODULE SHADING BANK WIRING DIAGRAMS AND ASSEMBLY STEPS The next sub sections...

Страница 42: ...ter modules do not have these series U Jumpers but instead are connected with wire Refer to the wiring diagram for each of the banks and notice that some locations don t use series U jumpers but rathe...

Страница 43: ...For clarification examine the photo above and refer to the bank 2 wiring diagram shown previously in Fig 15 7 4 3 Bank 3 Tweeter Wiring Diagram 11 12 13 14 Bank 3 Input 4 5 Black 4 5 Red 4 5 Black 4...

Страница 44: ...er wiring 24AWG and cutoffs from resistors Resistor Lead see photo below Fig 17 Banks 4 and 5 wiring diagram of the tweeter module shading network 7 4 4 1 View of Banks 4 and 5 Tweeter Module Wiring V...

Страница 45: ...ering Insulated Wire Jumpers to PC Board Make sure wire is exposed before soldering Note the nail polish applied to the mounting screw The nail polish will prevent the screw from coming out and will a...

Страница 46: ...top tweeter module and work your way down toward the bottom 8 2 3 Solder Insulated Lead Connections Attached to Tweeter Modules The next four photos indicate how to solder the insulated leads resistor...

Страница 47: ...to allow any trash to fall into the ND91 magnet hole FOR PROPER OPERATION OF THE MID BASS DRIVERS THE MAGNET HOLES MUST REMAIN OPEN 8 3 2 Apply Glue to Magnet Apply a small bead of hot glue to the mag...

Страница 48: ...2 inch length 8 4 3 Wrap the Caulk Around Jumper Wrap the caulk around the long jumpers as shown 8 4 4 Press the Caulked Wire to the Magnet Press the caulk against the magnet and form a mound to hold...

Страница 49: ...mount of movement decreases as you move up towards the top of the speaker crossing the bank boundaries along the way 9 1 3 Tweeter Test Requires More Voltage Now we will repeat the test for the tweete...

Страница 50: ...80 Watts of power Due to the small size of the battery it can only deliver this power continuously for no more than about a minute 9 2 VERIFY SHADING BANK ATTENUATIONS 9 2 1 Connect Power Amplifier to...

Страница 51: ...module 1 and measure the voltage across all 18 modules by following the steps in the next subsection Even though some modules are in parallel it is a good idea to measure the voltage across each modu...

Страница 52: ...Install the Speakon connector with wires attached on the rear of the cabinet Orient as shown with the metal insert up Install two 6 x 3 4 inch screws Material List item 9 10 2 1 Load Acoustic Filler...

Страница 53: ...tions so the joints are tight 10 3 3 Cut Gaskets at Slots Cut the gasket in each screw slot and also at each slot at the end of the cabinet for both the mid bass and tweeter compartments 10 3 4 Push G...

Страница 54: ...CBT36K Assembly Manual Page of 89 10...

Страница 55: ...cabinet and install all screws After all screws are installed work your way around the cabinet tightening in a zigzag pattern See the next page for troubleshooting screw installation problems DO NOT...

Страница 56: ...C Audio SweepGen signal generator a suggested generator test setup is shown at the end of this section in subsection 10 2 3 Generator Settings 11 2 1 Mid Bass Test 1 We will start with the mid bass dr...

Страница 57: ...panel settings for the PC Audio SweepGen signal generator for the 50 Hz to 1 kHz sweep refer to the previous Audio Measurement Tools section for more information on this generator Either a Fast smooth...

Страница 58: ...speakers or two 2 way speakers plus a subwoofer A table at the end of this section has a complete list of all the crossover filter and equalization settings that are required for the CBT36 This table...

Страница 59: ...ter types might work we cannot guarantee the performance of CBT36 if you choose a different crossover filter Here are examples of filters in the following listing BUT24 FREQ 20Hz means a Butterworth h...

Страница 60: ...low notes such as bass clarinet and pipe organs and allow the greater overall volume level 12 1 6 DSP Crossover Architecture The Behringer DCX2496 architecture is broken down into sections and some se...

Страница 61: ...DCX249 6 aspx 12 1 9 2 Configure RS232 Serial Communications Channel Navigate to setup page 5 of 5 on the DCX2496 and make sure that port is set to PC RS232 Press SETUP PAGE and use the PARAM to highl...

Страница 62: ...When you press one of the output keys the display will show 1 of 8 possible pages Navigation to a specific field is accomplished the same way as for the input channels using the PAGE PARAM and KNOB Ot...

Страница 63: ...for the right channel input B Remember that the third input C is not used Navigate to input A page 3 of 5 Press INPUT A PAGE PAGE and use the knob to turn the EQ ON The following photo shows the DCX2...

Страница 64: ...rameters to TYPE OFF The next photo shows the front panel display after these steps are completed 12 1 10 9 Step Seven Set Up Tweeter EQ The following six steps set up the tweeter EQ on output three w...

Страница 65: ...two steps the following photo shows the display for output one Not shown is the corresponding photo for output four 12 1 10 15 Step Twelve Set Up Subwoofer Filter Set the subwoofer low pass filter cro...

Страница 66: ...dB octave or 3 3 dB decade above 200 Hz See section titled The Flat Energy Response Debate in Appendix 2 for an explanation of the need for these two different response settings Each set shows the ac...

Страница 67: ...ver transfer functions LF blue HF red 12 1 11 4 Resultant CBT36 System Frequency Responses in Rolled Off Mode 1 dB octave Fig 25 CBT36 axial frequency responses 2 m out 1 m high with crossover is set...

Страница 68: ...ly to the left and right mid bass power amplifiers Outputs 3 and 4 connect respectively to the left and right tweeter power amplifiers Optional left and right sub woofers can connect respectively to o...

Страница 69: ...4 High Shelf 3240 3 0 6 5 High Shelf 6430 3 0 6 6 High Shelf 12800 3 0 6 7 High Shelf 20000 3 0 6 CD Correction Filter Rolled Off Mode Setting 1 Low Shelf 401 2 0 6 2 Low Shelf 805 2 0 6 3 High Shelf...

Страница 70: ...High Pass 1000 24 2 Low Pass OFF Tweeter EQ 1 Parametric 1000 4 5 6 3 2 High Shelf 1000 4 0 12 3 Parametric 1140 2 4 10 4 Parametric 1240 1 5 10 5 Parametric 3850 5 0 5 6 High Shelf 7010 3 0 12 7 Del...

Страница 71: ...vers The MUTE buttons on the front of the crossover can be used to good advantage here to MUTE an output channel you don t want to listen to First mute the tweeter channel and you only be listening to...

Страница 72: ...Y HIGH END AUDIO SYSTEM Fig 26 System connections for hooking up a pair of CBT36 systems with signal sources crossover EQ D A converters power amplifiers and sub woofers Note that the CBT36 systems ar...

Страница 73: ...gh efficiency The tweeters are mounted on PC boards in groups of four to ease assembly and optimize center to center spacing Eighteen four tweeter assemblies 72 tweeters in all are then mounted on the...

Страница 74: ...on in this appendix titled CBT36 Sensitivity and Maximum SPL for detailed information 14 1 10 System Requirements The system must be bi amped and requires an active DSP based loudspeaker crossover EQ...

Страница 75: ...r of the cabinet with bracing and mid woofer locations indicated The right illustration shows a front panel view of the CBT36 with the 18 mid woofers and 72 tweeter mounting holes shown Fig 27 CBT36 c...

Страница 76: ...erent frequencies 80 to 300 Hz 94 dB 800 Hz 89 dB 8 kHz 79 dB 14 1 12 5 Crossover Bi amped at 1 kHz with 4 th order Linkwitz Riley filters 24 dB octave slopes This very low crossover frequency insures...

Страница 77: ...separate containers All drivers and remaining parts are shipped in separate containers 14 1 13 CBT36 Impedance Magnitude and Phase vs Frequency The complex impedance magnitude and phase of the LF and...

Страница 78: ...both sections exhibits very low variation and is extremely well behaved Fig 30 Impedance phase of the LF section of the CBT36 The LF phase is also very well behaved and exhibits variations of only abo...

Страница 79: ...a pro sound configuration See previous comments in section CBT36 Specifications in Brief under specification Maximum Input Voltage and Power Fig 32 Graph of the approximate CBT36 2 83 Vrms 1m sensitiv...

Страница 80: ...and descriptions 14 1 15 1 Traditional 1 m Response Curve at 1 m from bottom of system 1 m high This frequency response was measured over a reflective ground plane at 1 m out from the bottom of the s...

Страница 81: ...4 1 Extremely Even and Uniform Frequency Response The CBT36 has very even frequency response from listening points ranging from up and down side to side and from near to far Up Down The frequency res...

Страница 82: ...d dots indicate loudspeaker locations a circular spherical cap array b elliptical toroidal cap array and c circular arc line array The first two arrays a and b control coverage in both planes while th...

Страница 83: ...g array the drivers in the center of the array are at a maximum while the drivers at the outside of the array are attenuated For the CBT36 ground plane array the drivers on the bottom near the floor a...

Страница 84: ...along with their attenuations Table 1 CBT36 Woofer and Tweeter Attenuation Banks Bank Number Attenuation Mid Bass Tweeters 1 Bottom 0 dB 6 Woofers Drivers 1 6 24 Tweeters Drivers 1 24 2 2 5 dB 4 Woofe...

Страница 85: ...he following figure shows the front panel of the CBT36 with the driver banks and attenuations indicated The CBT36 shading schematics are shown in the Shading Network sections of this assembly manual F...

Страница 86: ...HF bi amplification Secondly the circular shape guarantees circular constant phase wave fronts in the vertical plane from points very near the array to points very far away This means that the vertic...

Страница 87: ...r array is a power rolloff with increasing frequency as compared to a straight line array In the case of a curved arc CBT loudspeaker array the power rolloff is 10 dB decade or 3 dB octave throughout...

Страница 88: ...ow a photo of the rear side of both front panels laid out side by side will all wiring completed Carefully compare your final completed assemblies with this detailed high resolution photo before you a...

Страница 89: ...daytonaudio com epique tel 937 743 8248 info daytonaudio com 705 Pleasant Valley Dr Springboro OH 45066 USA 5 Year Limited Warranty See daytonaudio com for details Last Revised 11 8 2017...

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