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Operation Manual

I-Tech Series 

Power Amplifiers

page 44

9 Appendix B: Setting Sensitivity for Best Gain Staging

Optimized system gain structure maximizes signal to noise within the sys-
tem. Adjusting your amplifier to fit within an optimized system gain struc-
ture is accomplished by properly setting both the sensitivity and 
attenuation controls within the amplifier. I-Tech amplifiers offer 149 sensi-
tivity and gain settings allowing very fine adjustment of the amplifier’s gain 
and voltage sensitivity. The Appendix section of the I-Tech Application 
guide (online at www.crownaudio.com) provides charts with sensitivity in 
volts and gain in dB for each sensitivity/gain setting.

With other amplifiers, it is often necessary to apply attenuation in order to 
achieve the desired sound pressure level. Large amounts of attenuation are 
not necessary with I-Tech amplifiers and can, in fact, degrade performance. 
The attenuation adjustment should only be used for small (3 dB) or tempo-
rary adjustments in amplifier gain. Instead, set the sensitivity/gain of your 
I-Tech amplifier so that you can achieve the desired output with the attenu-
ators at or near 0 dB.

Example: Suppose that you are using an I-T8000 with the sensitivity/gain 
set at 1.4V/37.1 dB. After optimizing the gain structure of the rest of your 
system you find that attenuating the amplifier by 10 dB produces the 
desired loudness. The same output level, with improved signal-to-noise 
ratio and headroom, can be achieved by using 0 dB of attenuation and by 
setting the amplifier sensitivity/gain to 5.81V/27.0 dB (37 dB – 10 dB = 
27 dB).

Note: as indicated in the online appendix, the list of possible sensitivity 
settings is different for each position of the max input setting. If, while 
adjusting sensitivity/gain in your amplifier, you do not find the setting you 
need, try changing the status of the max input setting and search again.

Summary of Contents for I-Tech I-T4000

Page 1: ... manual was deemed accurate as of the publication date However updates to this information may have occurred To obtain the latest version of this manual please visit the Crown website at www crownaudio com Trademark Notice Crown Crown Audio IQ IQ System BCA and Amcron are registered trademarks of Crown International IQwic and TCP IQ are trademarks of Crown International HiQnet is a trademark of Ha...

Page 2: ...10 Protect the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus 11 Only use attachments accessories specified by the manufacturer 12 Use only with a cart stand tripod bracket or table specified by the manufacturer or sold with the apparatus When a cart is used use caution when moving the cart apparatus com bin...

Page 3: ...7 Electromagnetic Compatibility Product Family Standard for Audio Video Audio Visual and Entertainment Lighting Control Apparatus for Professional Use Part 2 Immunity EN 61000 4 2 2001 Electrostatic Discharge Immunity Environment E2 Criteria B 4k V Contact 8k V Air Discharge EN 61000 4 3 2001 Radiated Radio Frequency Electromagnetic Immunity Environment E2 criteria A EN 61000 4 4 2001 Electrical F...

Page 4: ... or to the 5 way binding posts as in Figure A 1 4 Turn down your mixer master faders Plug the power cord into the amplifier and then into an AC outlet Turn on the front panel power switch The LCD Control Screen will light up Figure A 3 5 Using both Encoder knobs Level controls set Attenuation to 0 dB Press the Menu Exit button then the Next button to access CH1 Sensitivity Turn an Encoder knob ful...

Page 5: ... across the red binding posts of both channels Figure A 5 Do not use the black binding posts in bridge mono mode 8 Turn down your mixer master faders Plug the power cord into the amplifier and then into an AC outlet Turn on the front panel power switch The LCD Control Screen will light up Figure A 3 9 Using both Encoder knobs Level controls set Attenuation to 0 dB Press the Menu Exit button then t...

Page 6: ...cators and Connectors 15 4 Advanced Operation 16 4 1 Advanced Operation Table of Contents 16 4 2 Navigating the LCD Control Screen 17 4 3 Presets 22 4 4 Digital Audio Options AES EBU 22 4 5 TCP IQ Networking 23 4 6 Software Controllable Onboard DSP 29 5 Troubleshooting 32 6 Specifications 34 6 1 Performance 34 6 2 Charts 36 7 AC Power Draw and Thermal Dissipation 37 8 Advanced Features 40 8 1 Prot...

Page 7: ...hannel AC mains indicator in power switch glows green when AC power is present Light weight due to aluminum chassis spe cial internal construction and switching power supply Thermal management controller and two dis crete thermal zones with variable speed fans forced air cooling The rear rack ears have a built in EZ Rack Pin for easier installation Advanced protection circuitry guards against shor...

Page 8: ...ounterclock wise Use a standard 19 inch 48 3 cm equipment rack EIA RS 310B See Figure 2 1 for ampli fier dimensions You may also stack amps without using a cabinet NOTE When transporting amplifiers should be supported at both front and back When using an equipment rack mount units directly on top of each other Close any open spaces in rack with blank panels DO NOT block front or rear air vents The...

Page 9: ...g basics Always use shielded wire for input wiring The higher the density of the shield the outer conductor the better Spiral wrapped shield is not recom mended When using unbalanced lines keep the cables as short as possible Avoid lengths greater than 10 feet 3 meters Do not run the audio input cables together with the high level wiring such as loudspeaker wires or AC cords This lessens the chanc...

Page 10: ...lly wired high quality two or four conductor heavy gauge speaker wire and connectors Use Class 1 output wiring You may use a 4 pole Figure 2 1 Balanced Analog Input Connector Wiring or AES EBU Digital Connector Wiring Figure 2 2 Unbalanced Analog Input Connector Wiring 2 Setup Speakon connector Figure 2 3 or banana plugs spade lugs or bare wire for your output connectors Figure 2 4 To prevent the ...

Page 11: ...re stereo speakers to the Speakon connectors use one of these methods Method 1 Table 1 and Figure 2 6 Wire one Speakon cable connector to two speakers Insert the Speakon cable connector into the amplifier s top Speakon connector Method 2 Table 2 and Figure 2 7 Plug the Channel 1 speaker into the Channel 1 top Speakon connector and plug the Channel 2 speaker into the Channel 2 bottom Speakon connec...

Page 12: ... 4 IMPORTANT Turn off the amplifier and unplug its power cord INPUTS There are three ways to connect an input signal to the amplifier Figure 2 9 Connect an analog signal source to the Channel 1 amplifier input Connect an AES EBU digital signal source to the Digital Input IN connector NOTE Crown provides a reference of wiring pin assignments for commonly used connector types in the Crown Amplifier ...

Page 13: ...ng subsonic signals to the amplifier High level low frequency signals from breath pops or dropped micro phones can blow out drivers To prevent subsonic signals use one of these methods Insert a highpass filter between mixer output and amplifier input or between mixer and limiter Use the I Tech s onboard DSP to set up a highpass filters Switch in highpass filters at your mixer Set the filter to as ...

Page 14: ...ur ing Thermal Level Control TLC limiting H Thermal Indicator Red LED one per channel illuminates when the channel has shut down due to thermal stress or overload I Fault Indicator Red LED one per channel flashes when the ampli fier output channel has stopped operating Usually this means that the amplifier must be serviced Signal Indicators Three green LEDS per channel indicate the ampli fier s in...

Page 15: ...h current 60A color coded 5 way binding posts Accepts banana plugs spade lugs or bare wire F Power Cord Connector Standard 20 amp IEC inlet Voltage range is indicated above IEC inlet G Reset Switch Circuit Breaker If the current draw of the amplifier exceeds safe limits this breaker automatically disconnects the power supply from the AC mains The switch resets the circuit breaker DIGITAL INPUTS SE...

Page 16: ...n 30 4 6 20 Memory Backup Configuration 30 4 6 21 Input Signal Router 31 4 6 22 Filters 31 4 6 23 Delay Latency 31 4 6 24 Noise Generator 31 4 6 25 Sine wave Generator 31 4 2 Navigating the LCD Control Screen 17 4 2 1 Introduction 17 4 2 2 Basic Menu 17 4 2 3 Advanced Menu 18 4 2 4 Monitor Menu 19 4 2 5 Operation Examples 21 4 2 6 Menu Tree 21 4 3 Presets 22 4 3 1 Introduction 22 4 3 2 User Preset...

Page 17: ...ting around in the Menu is intuitive Here are the basic opera tions Press Menu Exit to enter the main menu Press Next to go to the next item in the menu Press Prev to go to the previous item in the menu Turn or press either Encoder knob to change the value of the dis played parameter Press Menu Exit to leave the menu and return to the Attenuation screen at any time Basic Menu Items CH1 Sensitivity...

Page 18: ...DVANCED MENU When you see this screen press an Encoder knob to enter the Advanced Menu described next You can go to the Advanced Menu screen from the Attenuation screen by pressing Menu Exit Prev Prev Me You Amp Finder Allows users to identify a specific amplifier in a large network of amplifiers without having to compare address infor mation Me you can be turned on off from software and or the fr...

Page 19: ... Input AES EBU Input Trim Sets the gain of the AES EBU digital input signal Turn an Encoder to change the gain 12 0 12 0 AES EBU Input Trim AES EBU Input Trim 13 5 13 5 dB dB 4 2 4 MONITOR MENU This menu lets you monitor the status of the amplifier Starting from the Attenuation Screen press Menu then press Prev Or starting from the Advanced Menu screen press Next to go to the Monitor Menu screen T...

Page 20: ...emented and the operating time since the error is displayed To clear this screen press and release an Encoder The display will prompt you to confirm your choice by pressing and holding the Encoder NOTE You must use IQwic to enable error reporting and set its limits 44 44 Low Limit Load Errors Low Limit Load Errors 32 32 120 1 Hrs 120 1 Hrs 120 1 Hrs 120 1 Hrs Last Last High Limit Load Errors This ...

Page 21: ...2 6 Menu Tree As a handy reference Figure 4 2 shows the menu structure of the LCD control screen Once you are in a menu you can loop through its selections using the Next and Prev buttons The Menu Exit button returns you to the Attenuation screen which you see on power up You access the Monitor Menu title screen from the Attenuation screen by pressing Menu Exit Prev You access the Advanced Menu ti...

Page 22: ...up in IQwic Setting the parameters of the DSP in the I Tech amplifier is done using the IQwic software not by the amplifier s LCD Control Screen For example if you want to set filter Q compression ratio or graphic EQ you would do so within the IQwic software Adjusting DSP parameters within IQwic can be done in two ways with a software Wizard or directly The Wizard asks a series of questions to hel...

Page 23: ...s based on the IP address of the destination An IP address is made of four numbers separated by periods Each number can be zero to 255 The last number can never be a zero or 255 For example 126 126 17 1 could be an IP address 126 126 17 0 would not be a valid IP address A TCP IP or IP address has two parts the NETWORK ID and the HOST ID The NETWORK ID identifies the network and the HOST ID identif...

Page 24: ...ory 5 certified cable connecting it to a central con centrator most often a switch as in Figure 4 3 Detailed instructions follow 1 Using a standard Category 5 cable connect the network connector to a 100 Mb port on an Ethernet switch that is used to form the TCP IQ control network For more detail see Sec tion 9 TCP IQ Network Basics If the amplifier is not to be connected to a TCP IQ control netwo...

Page 25: ... NOT on the same network they are highlighted in the list 4 Make sure that each component has its own TCP IP address and there are no duplicate addresses The same holds true for IQ addresses 5 Assign a subnet mask Make it the same for all devices on the network If the network you are assembling will interconnect with other networks your network is considered to be a subnet within the larger networ...

Page 26: ...parated by periods For example 126 126 0 1 Select a subnet mask The subnet mask is four numbers between 1 and 255 separated by periods For example 255 255 0 0 1D Click OK and close the Control Panel At this point some computer operating systems will require a restart Figure 4 7 Internet Protocol TCP IP Properties Window 4 Advanced Operation The Internet Protocol TCP IQ Properties window appears Fi...

Page 27: ...covered Components 2B Once TCP IQ Utility has launched select a single component and click on Set Address In the Set Address window Figure 4 10 set up a TCP IQ address it must be unique Then set up the same Subnet mask for all of the components as well as the master computer Set the IQ address and select Send Code 2C Close the software Repeat as necessary Figure 4 10 Set Address Window 3 Launch IQ...

Page 28: ...resses This area is for your notes such as the IQ address or the component type In the CD ROM that came with your I Tech amplifier is an Excel spreadsheet that you can use to keep track of TCP IQ addresses EXAMPLE OF AN IQ ADDRESSING WORKSHEET ADDRESS IQ ADDRESS MODEL DESCRIPTION CHANNEL 1 CHANNEL 2 126 126 0 1 COMPUTER 126 126 0 2 2 I T8000 1 RACK ROOM LEFT CLUSTER RIGHT CLUSTER 126 126 0 3 126 1...

Page 29: ...limiting their drive level The thermal limiter feature of the I Tech s DSP can be set to engage at a pre selected thermal level 4 6 6 Power Standby Control Each channel can be independently turned on and off 4 6 7 Signal Mute The output signal of each channel can be independently muted This function produces 60 dB or more of attenuation 4 6 8 Polarity Inverter The input signal polarity of each cha...

Page 30: ...u must enter the loudspeaker s nomi nal impedance Attack Time Sets the attack time of the limiter The attack time is defined as the time it takes the limiter to attenuate the output signal by 20 dB The range is from 1 second to 30 seconds Release Time Sets the release time of the compressor The release time is defined as the time it takes the limiter to increase the output signal by 20 dB The rang...

Page 31: ... and Linkwitz Riley 4 Lowshelf Low frequency shelving EQ Highshelf High frequency shelving EQ Lowpass EQ Variable Q from 0 1 to 35 Highpass EQ Variable Q from 0 1 to 35 Parametric EQ Variable Q from 0 1 to 35 All Pass 1st and 2nd order All Pass filters provide no gain change to the output but provide a phase change at the selected frequency This corrects the phase relationship of the output withou...

Page 32: ...l level that is too high Turn down your amplifier level controls Encoders or turn down the input signal until the clip light goes out Note If the signal sounds distorted even though the Clip LED is off the input signal may be distorted before it reaches the amplifier input Check gain staging and output levels of the mixer or preamp 5 Troubleshooting Off Flashing On means that the LED can be off or...

Page 33: ...to speaker failure There is a short on the amplifier output First disconnect your speakers from the affected channel s one by one to determine if one of the loads is shorted CONDITION No input signal Signal indicator is not flashing even though audio is applied and the channel is ready POSSIBLE REASON Input signal level is very low CONDITION Data indicator not flash ing even though host computer I...

Page 34: ... maximum input level 15 dBu or 21 dBu depending on setting of maximum input level Latency analog digital inputs Analog 1 13 mS Digital See Table 5 below Analog 1 13 mS Digital See Table 5 below Analog 1 13 mS Digital See Table 5 below A D D A Converters 24 bit 96 kHz Cirrus Logic 24 bit 96 kHz Cirrus Logic 24 bit 96 kHz Cirrus Logic Digital Input AES EBU 24 bit 32 96 kHz Onboard sample rate conver...

Page 35: ...Line Connector USA UK European Australia India USA UK European Australia India USA UK European Australia India Construction I T4000 I T6000 I T8000 Ventilation Flow through ventilation from front to back Flow through ventilation from front to back Flow through ventilation from front to back Cooling Dual zone microprocessor controlled continuously variable speed fans Dual zone microprocessor contro...

Page 36: ...ion Manual I Tech Series Power Amplifiers page 36 Figure 6 1 Typical Frequency Response 1W Figure 6 3 Typical Damping Factor vs Frequency Figure 6 2 Typical Crosstalk vs Frequency 6 Specifications 6 2 Charts ...

Page 37: ...0 8 0 95 0 9 53 182 157 Idle awake 1 6 1 4 1 3 172 587 505 1 8th Power Pink Noise 8 Ohms Ch Typical of program material 16 Ohms Bridge just at clip 4 Ohms Ch 8 Ohms Bridge 2 Ohms Ch 4 Ohms Bridge 1 3rd Power Pink Noise 8 Ohms Ch Typical of program material 16 Ohms Bridge with severe clipping 4 Ohms Ch 8 Ohms Bridge 2 Ohms Ch 4 Ohms Bridge Load Thermal Dissipation 305 1413 356 5 3 94 6 59 6 64 9 11...

Page 38: ... 1 0 0 95 60 205 177 Idle awake 2 1 1 7 1 6 225 767 660 1 8th Power Pink Noise 8 Ohms Ch Typical of program material 16 Ohms Bridge just at clip 4 Ohms Ch 8 Ohms Bridge 2 Ohms Ch 4 Ohms Bridge 1 3rd Power Pink Noise 8 Ohms Ch Typical of program material 16 Ohms Bridge with severe clipping 4 Ohms Ch 8 Ohms Bridge 2 Ohms Ch 4 Ohms Bridge 6 6 4 2 3 8 57 6 91 2 99 8 392 1338 337 593 2024 510 13 6 8 1 ...

Page 39: ... 1 1 0 62 212 183 Idle awake 2 0 1 8 1 6 213 726 625 1 8th Power Pink Noise 8 Ohms Ch Typical of program material 16 Ohms Bridge just at clip 4 Ohms Ch 8 Ohms Bridge 2 Ohms Ch 4 Ohms Bridge 1 3rd Power Pink Noise 8 Ohms Ch Typical of program material 16 Ohms Bridge with severe clipping 4 Ohms Ch 8 Ohms Bridge 2 Ohms Ch 4 Ohms Bridge 441 1504 379 8 3 63 6 103 3 5 1 4 7 14 6 68 8 2394 603 14 2 764 2...

Page 40: ...uired power at the output stage These transformers must be large to operate at 50 to 60 Hz standard AC supplied by the power company By contrast switching power supplies can operate with a much smaller and lighter trans former because they first convert the AC up to a much higher frequency thereby reducing waste Power Factor Correction PFC controls how your amplifier draws current from the AC main...

Page 41: ...he use of an IP router Component firmware upgrades via the network Ethernet Networks are established through the use of either a hub or a switch These devices are centralized in the network and transfer the Ethernet data from point to point Ethernet data is transferred in data packets that have addresses coded into their structure Hubs and switches decipher these addresses and route the data packe...

Page 42: ...ed on the outside of every IQ component and is shown in hexadecimal for mat as 6 two byte octets such as 00 0A 40 00 DC 2F Internet Protocol IP Address The IP address of a component is assigned during the setup of the network and identifies the IQ compo nent to a larger audience Because the MAC address is limited to a sin gle physical LAN communications between LANs is impossible solely through th...

Page 43: ...IP addresses can be assigned to a particular LAN The Subnet Mask is also four numbers 0 255 sepa rated by periods For example a subnet mask of 255 255 0 0 and an IP address of 126 126 1 123 says that all IP addresses in that LAN are in the IP address range of 126 126 1 1 to 126 126 1 255 If a TCP IQ controller is on a different network than the TCP IQ compo nents communications must occur through ...

Page 44: ...ssary with I Tech amplifiers and can in fact degrade performance The attenuation adjustment should only be used for small 3 dB or tempo rary adjustments in amplifier gain Instead set the sensitivity gain of your I Tech amplifier so that you can achieve the desired output with the attenu ators at or near 0 dB Example Suppose that you are using an I T8000 with the sensitivity gain set at 1 4V 37 1 d...

Page 45: ... being sent to the factory for service Please complete the SRA by going to www crownaudio com support factserv htm If you do not have access to our website call 1 800 342 6939 extension 8205 and we ll create the SRA for you 2 See packing instructions that follow 3 Ship product to CROWN AUDIO FACTORY SERVICE 1718 W MISHAWKA RD ELKHART IN 46517 4 Use a bold black marker and write the SRA number on t...

Page 46: ...er or our factory All expenses in remedying the defect including surface shipping costs in the United States will be borne by us You must bear the expense of shipping the product between any for eign country and the port of entry in the United States including the return shipment and all taxes duties and other customs fees for such for eign shipments HOW TO OBTAIN WARRANTY SERVICE You must notify ...

Page 47: ...st insurance closing costs and other finance charges less a reasonable depreciation on the product from the date of original purchase War ranty work can only be performed at our autho rized service centers We will remedy the defect and ship the product from the service center within a reasonable time after receipt of the defec tive product at our authorized service center HOW TO OBTAIN WARRANTY SE...

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Page 49: ...________________________ Other equipment in your system _________________________________________________________________________________________________________________________________________________________ If warranty is expired please provide method of payment Proof of purchase may be required to validate warranty PAYMENT OPTIONS I have open account payment terms Purchase order required PO __...

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