1. Sound Re-enforcement System (PA) at St. James Church, Taunton
Current situation, as discussed with installer Dan Saturday 22nd March 2014
File: SJC_PA_3Oct15_v4.ppt P.A Team

2. Introduction
The information in this document was largely gleamed during a handover meeting with Dan on 22nd March Richard, Bob and Norman attended.
This is a record of the system configuration at this date, anticipating that this will change.

3. Simplified Block Diagram (system)
Mixer Head Unit B
Stage Box
Front of house speakers
Foldback
Mixer Head Unit A
Foldback
LS Management System (Bottom)
Main Amplifier
(4 channels) x4
Loop Amplifier
100 V line amplifier
Various locations
Main Amplifier
(4 channels) x4
LS Management System (Top)
Sub Amplifier
(single channel)
NOTE: The outputs from the two mixer head units are just ‘T’ed together
Sub Amplifier
(single channel)

4. Simplified Block Diagram (sources)
Rack mounted
UHF Radio Mic Receivers
VHF Radio Mic Receivers
Mixer Head Unit B
Stage Box
Mixer desk
Lectern mic
Mixer Head Unit A
Mixer desk
Cat-5 Ethernet

5. Rack Layout Photo now out of date text Mixer Head Unit B
Mixer Head Unit A space
UHF Radio Microphones (x2) RM distribution amplifier
LS Management System (x2)
Main Power Amplifier 1
Main Power Amplifier 2
Sub Power Amplifier 1
Sub Power Amplifier 2

6. Other equipment
Older VHF radio microphone receivers located above the entrance door to the vestry
Loop amplifier on shelf adjacent to LHS of organ. Loop is installed at ground level, around congregational area only, i.e. not the chancel
VHF and UHF radio microphone antennas on RHS of organ, both feeding distribution amplifiers into multiple receivers
100 V line amplifier feeding multiple auxiliary loudspeakers within the building
Foldback loudspeakers utilising self-powered PA units

7. Power Amplifier Gain Settings
Need a better photograph

8. Loudspeaker & Power Amplifier Mapping
Sub N ?
Sub Amp 1
Sub S ?
Sub Amp 2 NF FL FR SF 3 M1 M2 1
Amp 2 - ch 3
Amp 1 - ch 1
Amp 1 - ch 2
Amp 2 - ch 1 RL RR M3 M4 NR
Amp 1 - ch 3
Amp 1 - ch 4 SR 4 2
Amp 2 - ch 4
Amp 2 - ch 2
name
cable
amplifier
Key
Plan view of front of house loudspeakers, chancel at the top

9. Loudspeaker Channel Filters & Delays
Sub N ?
zero
Sub S ?
zero NF FL FR SF
HPF 68 Hz
HPF 68 Hz
HPF 68 Hz
HPF 68 Hz
6m,17.47mS
2 m, 5.82mS
2 m, 5.82mS
2 m, 5.82mS RL RR
HPF 68 Hz
HPF 68 Hz NR
8 m, 23.29mS
8 m, 23.29mS SR
HPF 98 Hz
HPF 98 Hz
15m,43.67mS
11m,34.02mS
name
filters
delays
Key
The loop and 100 V line feeds have zero delay
Plan view of front of house loudspeakers, chancel at the top

10. LMS Output Gain Sub N ? Sub S ? NF FL FR SF ? ? ? ? ? ? ? ? RL RR ? ?NR ? ? SR ? ? ? ?
name
Gain
Key
EQ profile
Loop
100 V ? ? ? ?
Plan view of front of house loudspeakers, chancel at the top

11. Behringer Loudspeaker Management System channel mapping
Amplifier
Sig Cable
LS Cable LS
Top ch 1
Main Amp 1 ? M1 FL
Top ch 2 M2 FR
Top ch 3 M3 RL
Top ch 4 M4 RR
Top ch 5
Sub Amp 1
Sub N
Top ch 6
Sub Amp 2
Sub S
Bottom ch 1
Main Amp 2 1 SF
Bottom ch 2 2 SR
Bottom ch 3 3 NF
Bottom ch 4 4 NR
Bottom ch 5
Loop Amp
Bottom ch 6
100 V line
This table needs extending to show the complete signal path

12. Fostex mixer desk
The input channels of the mixers follows standard PA practice, i.e. matched to signal source. It should not be necessary to record these.
Desk A (Left Hand Side) used for music group.
Aux 1 is run Pre-Fade for foldback use
Aux 2 is run Pre-Fade for foldback use
Aux 3 is fixed as Post-Fade and is used for foldback use when absolutely necessary (not recommended)
Desk B (Right Hand Side) used for voice / radio microphone channels.
Aux 1 is generally run Post-Fade with the Lecturn Mic channel run as Pre-Fade. Aux 1 is monitored using the Pre-Fade Listen (PFL) otherwise known as ‘Solo’. This monitoring output feeds the local CD recorder.
The two mixers currently run isolated.

13. Outstanding Information and Tests
Loudspeaker Management System (LMS) output levels and equalisation settings
Investigation of LMS limit points and the effect on audio quality (especially the loop and 100 V line as these seem to be regularly limiting
Gain structure across system, with particular attention to the mixer desk indications relative to the rest of the system. Some limiting seems to be occurring when the desk is indicating -10 dBm.

14. Other notes from meeting
Loudspeaker Management System (LMS) equalisation profile intended to achieve flat response out of each speaker. All correction is using attenuation, not boost, maximum of 2.3 dB. All input channels use same profile.
High Pass Filters crossover at 68 Hz and 98 Hz.
Same DSP profile used on both LMS units.
Power Amplifiers all set for maximum input of 0dBm to give maximum output of amplifier.
LMS password is Either ‘Page Lock’ or a ‘Global Lock’ for all pages can be used.
LMS has three inputs but can only summate two of them, i.e. A+B, B+C or A+C.
LMS has used default labels for routing and hence do not always make sense.
Configuration profiles can be saved to internal memory, memory card or via serial link to PC.

15. Thoughts for development (updated 2)
Tidy up PA rack cabling, including labelling of all cables >> largely complete.
Move both mixer head ends into view arch >> complete
Conduct further Radio Frequency Interference (RFI) tests and resolve, possibly including the installation of a local clean earth. >> stage box cable (snake) rewired both ends and RFI filtering modified.
Use of radio microphone for lectern (now regularly used)
Better foldback speaker positioning (in progress)
Relocate the loop amplifier where we can get at it
Investigate high pitched tone, believed to be electrical feedback between hearing aid induction loop and chancel guitar >> confirmed, resolved by using new guitar pickup.
Unless I have made a mistake (could be!), the channel mapping from the Behringer LMS to the amplifiers is a bit funny, e.g. the bottom LMS seems to feed the top amplifier and vice versa. We might wish to make this a bit more logical.
Move to direct MP3 recording. >> PC recording using WMA format in trial.
Combining of both desks, i.e. one set of master gains used. Or combine using one of the aux outputs into one channel of the other mixer.

16. Next steps Check LMS input channels use flat EQ, or record EQ profile
Check LMS input channel gain and routing / summation
Record gain on LMS for each output channel
Check LMS output limits, per channel
Populate any missing data on plan layouts (earlier in this document)
Create Excel sheet table listing signal path for each channel (see next page), taking data from the plan layout sheets and possibly other records. This will become the master record.
Consider renaming speakers >> maybe also reassign amplifier channels as we have noted that the two FOH amplifiers have different power ratings?????

17. Excel signal path parameters
This chart will be used to record signal paths from the Loudspeaker Management System (LMS) onwards.
It is anticipated that the following columns will be used, amongst others: (see diagram on next page for LMS unit block diagram)
LMS unit (top or bottom)
LMS input channel 1 gain (of ‘off’ is no route)
LMS input channel 1 delay, EQ, Dynamic EQ
LMS input channel 2 gain (of ‘off’ is no route)
LMS input channel 2 delay, EQ, Dynamic EQ
LMS input channel 3 gain (of ‘off’ is no route)
LMS input channel 3 delay, EQ, Dynamic EQ
LMS output channel (1 to 6)
LMS output gain
LMS output limiter setting
LMS output EQ profile (multiple columns for each sub-band?)
LMS output delay
Cable name
Speaker name or load name, e.g. NF, loop, etc
A separate chart may be used for the mixer inputs, however, this is likely to all change so it may not be worth recording these.

18. Behringer LMS
This is the signal flow diagram of the Behringer Ultradrive Pro DCX2496 Loudspeaker Management System.