THTR 357-Intro to Audio Technology Tech Lecture 7: Block Diagrams

THTR 357-Intro to Audio THTR 357-Intro to Audio TechnologyTechnology

Tech Lecture 7: Block DiagramsTech Lecture 7: Block Diagrams

IntroductionIntroduction

This section discusses block diagrams and speaker This section discusses block diagrams and speaker plots, with specific application to theatre plots, with specific application to theatre productions. productions.

Remember that although there is still a great deal Remember that although there is still a great deal of variety used in graphically notating sound of variety used in graphically notating sound systems (even thought sub-committees exist in systems (even thought sub-committees exist in AES USITT and NSCA to standardize these AES USITT and NSCA to standardize these symbols)symbols)

7.1 General Discussion7.1 General Discussion

A block diagram is a graphic description of the A block diagram is a graphic description of the signal path through a device, or series of devices.signal path through a device, or series of devices.

The block diagram consists of individual The block diagram consists of individual functional entities connected in a specific way.functional entities connected in a specific way.

The purpose of a block diagram is to present the The purpose of a block diagram is to present the logical structure of equipment in simple, readily logical structure of equipment in simple, readily accessible form.accessible form.


Example:Example:The sound designer, or system engineer sends a block The sound designer, or system engineer sends a block diagram to the shop, and the shop builds and installs the diagram to the shop, and the shop builds and installs the

system according to the block diagram.system according to the block diagram. This happens frequently on touring shows, or shows This happens frequently on touring shows, or shows

designed by out of town designers, etc. designed by out of town designers, etc. The system engineer or designer may never see the system The system engineer or designer may never see the system

until after it has been fully installed. Mistakes can be until after it has been fully installed. Mistakes can be extremely costly, both in terms of time and money. extremely costly, both in terms of time and money.

Because of the high cost of mistakes, great care must be Because of the high cost of mistakes, great care must be exercised when preparing block diagrams.exercised when preparing block diagrams.


Examples of Block Diagrams:Examples of Block Diagrams:– Signal processing equipment (mixers, delays, eq., etc, found Signal processing equipment (mixers, delays, eq., etc, found

in product data sheetin product data sheet– Instruction manualInstruction manual– System Block Diagram (e.g. theatre productions, touring System Block Diagram (e.g. theatre productions, touring

shows, etc. NOTE: see Section 17, pp. 213-224 of Yamaha shows, etc. NOTE: see Section 17, pp. 213-224 of Yamaha Manual)Manual)

Be carefull not to confuse Be carefull not to confuse blockblock diagrams with diagrams with schematicschematic (component level) diagrams. (component level) diagrams.


Two Fundatmental Caveats:Two Fundatmental Caveats:

Always organize the block diagram to show Always organize the block diagram to show how the signal flows through the system.how the signal flows through the system.

Remember that the block diagram presents Remember that the block diagram presents the logical organization of a device or a the logical organization of a device or a system.system.


We will concentrate on symbols commonly We will concentrate on symbols commonly used in System Block Diagrams, such as used in System Block Diagrams, such as those used to prepare sound systems for the those used to prepare sound systems for the Performing Arts, sound system consulting Performing Arts, sound system consulting and contracting, etc. and contracting, etc.

For variations that relate to reading or For variations that relate to reading or creating component block diagrams, consult creating component block diagrams, consult the text.the text.

7.2 Symbolic Conventions7.2 Symbolic Conventions7.2.1 Amplifiers7.2.1 Amplifiers

Amplifiers are always denoted by a triangle.Amplifiers are always denoted by a triangle. System Block Diagrams typically show power System Block Diagrams typically show power

amplifiers (although amplifiers (although outboardoutboard preamplifiers preamplifiers appear as triangles also).appear as triangles also).

We use two types: single channel (often used with We use two types: single channel (often used with amps bridged for mono output), and dual (most amps bridged for mono output), and dual (most common type, used with amps powering two full common type, used with amps powering two full range loudspeakers, or the low frequency and high range loudspeakers, or the low frequency and high frequency drivers in bi-amped systems).frequency drivers in bi-amped systems).

Preamp or Single Channel Power

Amplifier

Two Channel Power

Amplifier

7.2 Symbolic Conventions7.2 Symbolic Conventions7.2.2 Other Devices7.2.2 Other Devices

All other devices that exhibit unity gain, or loss are All other devices that exhibit unity gain, or loss are denoted with a rectangle, except loudspeakers.denoted with a rectangle, except loudspeakers.

The name of the device is centered in the box, or The name of the device is centered in the box, or placed nearby if it is not practical to include it in placed nearby if it is not practical to include it in the box.the box.

All devices on the block diagram (including All devices on the block diagram (including amplifiers and loudspeakers) must show make and amplifiers and loudspeakers) must show make and model number.model number.

Unity Gain or Attenuating

Device

Yamaha Rev 5

7.2 Symbolic Conventions7.2 Symbolic Conventions7.2.2 Other Devices7.2.2 Other Devices

Straight lines of medium thickness are used to Straight lines of medium thickness are used to show equipment interconnection.show equipment interconnection.

Where there is potential ambiguity regarding Where there is potential ambiguity regarding inputs and outputs, the name of the input or output inputs and outputs, the name of the input or output (as it appears on the rear of the device) is shown in (as it appears on the rear of the device) is shown in the box.the box.

This is almost always the case with mixing consoles.This is almost always the case with mixing consoles.

Mackie 16041

2

Sub Out 1

Sub Out 2

7.2 Symbolic Conventions7.2 Symbolic Conventions7.2.3 Loudspeakers7.2.3 Loudspeakers

Loudspeakers are shown as a single driver, even if Loudspeakers are shown as a single driver, even if they employ passive crossoversthey employ passive crossovers

Biamplified loudspeakers are shown as separate Biamplified loudspeakers are shown as separate elements to make connection to amplifier channels elements to make connection to amplifier channels clear.clear.

Loudspeaker Biamplifierd

Loudspeaker

7.2 Symbolic Conventions7.2 Symbolic Conventions7.2.4 Other Commonly Used Symbols7.2.4 Other Commonly Used Symbols

FaderPadTransformerSwitchMikeAutoformerSignalGround

EarthGround

ChasisGround

IntercomHeadsetStereoHeadsetOscillator


MaleConnector

FemaleConnector•ConnectedCrossed PathsUnconnectedCross PathsReel to

ReelDeck

KeyboardCassette DeckCD

PlayerMiniDisc

PlayerOrInsert Point


A Title Block should include the following A Title Block should include the following information:information:

Title or VenueVenue Name, AddressDirected by:Scale: NoneDate:Sound Designer:Plate: of bySystem Block DiagramSystem Designer:Revised:

7.3 Notational Conventions7.3 Notational Conventions

Block diagrams usually are created so that signal Block diagrams usually are created so that signal flows from left to right--inputs on the left, and flows from left to right--inputs on the left, and outputs on the right. outputs on the right.

Feedback loops such as signal processors will Feedback loops such as signal processors will typically be routed in the opposite direction.typically be routed in the opposite direction.

Offstage VoiceAKG 535

22 27 28 Effects 3 (Post)Effects 2 (Post)YamahaSPX 1000

Lexicon 224 InLexicon224

2930Effects 2 (Post)

7.2 Symbolic Conventions7.2 Symbolic Conventions7.3 Notational Conventions7.3 Notational Conventions

It is usually not necessary to provide individual labels for It is usually not necessary to provide individual labels for separate channels of two channel devices such as separate channels of two channel devices such as processors, amps and speakers. Convention dictates that processors, amps and speakers. Convention dictates that the top or left component is the left channel or channel 1, the top or left component is the left channel or channel 1, and the bottom or right component is the right channel or and the bottom or right component is the right channel or channel 2.channel 2.

Crown Macrotech1200 Truss Center

Meyer UPA 1B

7.5 Analysis of Simple Block Diagrams7.5 Analysis of Simple Block Diagrams

Pin 1 of XLR is groundPin 1 of XLR is ground Pin 2 (hot) is transformer isolatedPin 2 (hot) is transformer isolated Differential input amplifier (e.g. balanced) vs. single-endedDifferential input amplifier (e.g. balanced) vs. single-ended Rotary gain controls gain of amplifier, not level going into Rotary gain controls gain of amplifier, not level going into

amplifier 6-40 dBamplifier 6-40 dB

+-


Pin 2 (hot) goes to + of amp (e.g. normal polarity)Pin 2 (hot) goes to + of amp (e.g. normal polarity) Pin 3 (neutral) follows - sign through to pin 3 of line outputPin 3 (neutral) follows - sign through to pin 3 of line output Note that most single ended amplifiers invert the polarity of Note that most single ended amplifiers invert the polarity of

the signal. This may or may not be restored to normal the signal. This may or may not be restored to normal polarity internallypolarity internally

+-


11 stages of EQ in series:11 stages of EQ in series:High Pass Filter (variable frequency)High Pass Filter (variable frequency)Low pass filter (variable frequency)Low pass filter (variable frequency)9 Bands of graphic EQ with variable boost/cut9 Bands of graphic EQ with variable boost/cut

Transformer isolated balanced outputTransformer isolated balanced output

+- HPFFrequency

LPFFrequency

Band 1Boost/Cut

Band 9Boost/Cut


Non-inverting circuit in which pin 2 is hot. ALWAYS Non-inverting circuit in which pin 2 is hot. ALWAYS make sure by consulting owners manual or checking.make sure by consulting owners manual or checking.

Fixed gainFixed gain EQ/Bypass switch EQ/Bypass switch EQ feeds single ended non-inverting amplifier EQ feeds single ended non-inverting amplifier

+- HPFFrequency

LPFFrequency

Band 1Boost/Cut

Band 9Boost/Cut


Block diagram shows only logic structure of device.Block diagram shows only logic structure of device. Input control level in a buffering amplifierInput control level in a buffering amplifier Low pass anti-aliasing filter to prevent digital distortion. Low pass anti-aliasing filter to prevent digital distortion.

Dry signal picked off after this point.Dry signal picked off after this point.

+A/DD/AMemoryVCO(CLock)

LFO-InputInputLevelAnti-Aliasing

FilterFeedback

In/OutFeedback

LevelFeedbackPolarity

MixOutputReconstruction Filter

DelayTime

ModulationRate

Modulation Depth

Delay Time Select


Feedback combined with original signal next. Note that Feedback combined with original signal next. Note that feedback loop is analogue. Note polarity reversal switch and feedback loop is analogue. Note polarity reversal switch and level control in feedback loop. Feedback allows creation of level control in feedback loop. Feedback allows creation of multiple echoes, reverberation, flanging, etc. depending on time multiple echoes, reverberation, flanging, etc. depending on time delays chosen.delays chosen.



FilterFeedback

In/OutFeedback



DelayTime

ModulationRate

Modulation Depth

Delay Time Select


A/D converts analogue to digital.A/D converts analogue to digital. Memory delays signal (note user controls).Memory delays signal (note user controls). D/A follows and converts signal back to analogue.D/A follows and converts signal back to analogue. Dry/wet mix control followed by low pass filter to remove memory's Dry/wet mix control followed by low pass filter to remove memory's

clock frequency.clock frequency.



FilterFeedback

In/OutFeedback



DelayTime

ModulationRate

Modulation Depth

Delay Time Select


Voltage controlled oscillator (VCO) controls clock rate which Voltage controlled oscillator (VCO) controls clock rate which controls delay time. Low frequency oscillator (LFO-controls delay time. Low frequency oscillator (LFO-typically .01-20 or 100 Hz) allows delay time to be modulated typically .01-20 or 100 Hz) allows delay time to be modulated by, in this case, a triangle wave. LFO frequency controls rate by, in this case, a triangle wave. LFO frequency controls rate of modulation.of modulation.



FilterFeedback

In/OutFeedback



DelayTime

ModulationRate

Modulation Depth

Delay Time Select

7.6 The Speaker Plot7.6 The Speaker Plot

The Speaker Plot is a separate but crucial diagram The Speaker Plot is a separate but crucial diagram used in sound system design. used in sound system design.

The Speaker Plot is not intended to show how The Speaker Plot is not intended to show how equipment is connected, or to give an understanding equipment is connected, or to give an understanding of signal flow, but to depict the location of sound of signal flow, but to depict the location of sound system components that have an important physical system components that have an important physical relationship to the theatre space. relationship to the theatre space.


The speaker plot includes all loudspeakers, The speaker plot includes all loudspeakers, practicals (i.e. sound effects devices such as practicals (i.e. sound effects devices such as doorbells, wind machines, telephones, etc.), racks, doorbells, wind machines, telephones, etc.), racks, consoles, microphones and cables shown in their consoles, microphones and cables shown in their exact location in the space. exact location in the space.

Where possible, and necessary to the proper Where possible, and necessary to the proper installation, objects are shown scaled to proper installation, objects are shown scaled to proper size.size.

7.6 The Speaker Plot7.6 The Speaker Plot Where possible, and necessary to the proper installation, Where possible, and necessary to the proper installation,

objects are shown scaled to proper size. In situations where objects are shown scaled to proper size. In situations where an object is physically smaller than can be accurately an object is physically smaller than can be accurately depicted, or size is not of concern in the implementation, a depicted, or size is not of concern in the implementation, a symbol may be used, accompanied by an explanatory key. symbol may be used, accompanied by an explanatory key.

If the Sound System Designer is responsible for If the Sound System Designer is responsible for intercommunications systems, these locations must intercommunications systems, these locations must also be included on the Speaker Plot. also be included on the Speaker Plot.

Key:microphonespeaker cableheadset cableheadset


The Speaker Plot is typically constructed using the The Speaker Plot is typically constructed using the Ground Plan and Section of the set and Ground Plan and Section of the set and auditorium, as furnished by the scene designer.auditorium, as furnished by the scene designer.

Hopefully, the Ground Plan and Section will be Hopefully, the Ground Plan and Section will be submitted in software form, to make it easy for the submitted in software form, to make it easy for the Sound System Designer to modify into a useful Sound System Designer to modify into a useful form. form.


These modifications include:These modifications include:1. Remove all non-essential details from the plot such as set 1. Remove all non-essential details from the plot such as set dimensions, labels, construction notes, etc. If an item has no dimensions, labels, construction notes, etc. If an item has no bearing bearing on the sound installation it probably is not needed on the plot;on the sound installation it probably is not needed on the plot;

2. Keep the basic outline of the set, or sets, but use a very light guage 2. Keep the basic outline of the set, or sets, but use a very light guage pen thickness to ensure that the scenic elements always appear in the pen thickness to ensure that the scenic elements always appear in the background;background;

3. Use a slightly thicker pen to draft cables, including snake, speaker 3. Use a slightly thicker pen to draft cables, including snake, speaker cables, etc.cables, etc.

4. Use an even thicker guage to draft objects such as speakers, console 4. Use an even thicker guage to draft objects such as speakers, console location, rack locations, etc.location, rack locations, etc.


5. Make sure that speaker dimensions are accurate, and shown 5. Make sure that speaker dimensions are accurate, and shown on both the Ground Plan and the Section. This is necessary to on both the Ground Plan and the Section. This is necessary to make sure that:make sure that:

They fit in the scenery the way they are intended to fit;They fit in the scenery the way they are intended to fit;

They aren't in the way of other scenery;They aren't in the way of other scenery;

They have clear, unobstructed sightlines to the audience, if desired;They have clear, unobstructed sightlines to the audience, if desired;

The location of the horns is clearly specified.The location of the horns is clearly specified.

6. The Speaker Plot is typically given to the Tech Director, who is 6. The Speaker Plot is typically given to the Tech Director, who is responsible for any working drawings that need to be responsible for any working drawings that need to be accomplished to get the speakers rigged, located in scenery, etc.accomplished to get the speakers rigged, located in scenery, etc.

7.7 The Shop Order7.7 The Shop Order

The final component of the technical drawings is the shop The final component of the technical drawings is the shop order.order.

The shop order is used to collate every piece of equipment The shop order is used to collate every piece of equipment required by the production.required by the production.

Rental Shops typically prepare their bids based on the shop Rental Shops typically prepare their bids based on the shop order, and producers base their budgets on the shop order.order, and producers base their budgets on the shop order.

Therefore, every single piece of equipment, cable, Therefore, every single piece of equipment, cable, interconnect, direct box, transformer, snake, etc., must be interconnect, direct box, transformer, snake, etc., must be accurately specified in the shop order.accurately specified in the shop order.

7.7 The Shop Order7.7 The Shop Order

If this doesn’t happen, there will typically be no If this doesn’t happen, there will typically be no money in the budget to rent additional money in the budget to rent additional equipment, and the sound designer will have to equipment, and the sound designer will have to figure out how to do without. figure out how to do without.

Shop orders that are consistently erroneous or Shop orders that are consistently erroneous or incomplete will cause sound designers or incomplete will cause sound designers or systems engineers to get very good at job systems engineers to get very good at job

hunting!hunting!

Documents

THTR 357-Intro to Audio Technology Tech Lecture 7: Block Diagrams