Meyer Sound Ashby-5C Operating Instructions Manual page 12

CHAPTER 2: CONNECTING ASHBY LOUDSPEAKERS
Cable Length and Gauge
The maximum cable length depends on the type and number
of loudspeakers looped and the gauge of the cable. Table 1
shows the maximum cable length for Ashby loudspeakers
using 18 AWG cable with only 1 dB of peak SPL loss.
CAUTION: The minimum cable gauge and type
!
of wire must conform with national and regional
electrical and building codes where loudspeakers are
installed. The maximum number of loudspeakers
shown in Table 1 results in a maximum 3 second aver-
age power within Class 2 wiring limits in most coun-
tries.
Using 18 AWG wire, a single Ashby-5C loudspeaker can use
up to 450 ft of cable (300 ft for Ashby-8C) from the MPS Power
Supply and lose no more than 1 dB of peak SPL. Unlike 70 V
line-distributed loudspeakers, Ashby loudspeakers do not
suffer gain loss with the long 18 AWG cables.
Table 1: Maximum cable length using 18 AWG cable
Model Number of loud-
speakers
Ashby-5C
Ashby-8C
Table 2 shows the maximum cable runs for a single channel of
an MPS Power Supply powering up to 3 Ashby-5C or one
Ashby-8C and one looped Ashby-5C, with different wire
gauges. Table 3 shows the same information for European
cable gauges.
Table 2: Maximum cable length for different numbers of Ashby
loudspeakers using four different gauge wires (AWG)
Maximum Cable Length (ft)
Number of
Model Loud-
speakers
1
Ashby-5C 2
3
1
Ashby-8C
2*
*Applies to one Ashby-8C with one looped Ashby-5C
12
Maximum Cable
Length (ft)
1 470
2 235
3 156
1 313
2 157
12 AWG 14 AWG 16 AWG
0.0016 0.00253 0.00402
Ω Ω Ω
( /ft) ( /ft) ( /ft)
1800 1125 700
900 550 350
600 375 237
1200 750 475
600 375 237
NOTE:
from long analog audio cables. For lengths
greater than 500 ft Meyer Sound recommends using
low capacitance shielded audio cable or AES Digital
audio cable. Discuss expected high frequency loss with
the cable manufacturer to determine acceptability.
Table 3: Maximum cable length for different numbers of Ashby
loudspeakers using four different gauge wires (m)
Number of
Model
Loud-
speakers
Ashby-5C
Ashby-8C
*Applies to one Ashby-8C with one looped Ashby-5C
NOTE:
from long analog audio cables. For lengths
greater than 150 m Meyer Sound recommends using
low capacitance shielded audio cable or AES Digital
audio cable. Discuss expected high frequency loss with
the cable manufacturer to determine acceptability.
The maximum total cable resistance between one Ashby-5C
loudspeaker and its external power supply is 6
one Ashby-8C.
When using the maximum number of loudspeakers per chan-
nel (3 Ashby-5C or 2 Ashby-8C), it should not exceed 2
Calculating the Maximum Cable Length
18AWG
The maximum cable length for an Ashby loudspeaker can be
0.00636
calculated using the formulas shown below. The Wire Resis-
Ω
( /ft)
tance Per Foot (WRPF) is the resistance (in
individual wire of the chosen gauge. Enter the WRPF in the
450
equations below to determine maximum cable length. The
225
equations compensate for round trip length.
150
For 18 AWG, WRPF = 0.006385
Ashby-5C: Maximum length (ft) = 3 / (WRPF x # of Ashby-5C)
300
Ashby-8C: Maximum length (ft) = 2 / (WRPF x # of Ashby-8C)
150
To calculate the maximum length in meters, substitute the
Wire Resistance per Meter for the selected wire gauge.
Some high frequency loss can occur
Maximum Cable Length (m)
2.5 mm2 1.5 mm2
0.0052 0.01076
Ω Ω
( /m) ( /m)
1 480 260
2 240 130
3 160 87
1 320 175
2* 160 87
Some high frequency loss can occur
Ω
1.0 mm2 0.75 mm2
0.02087 0.03307
Ω Ω
( /m) ( /m)
135 80
70 40
45 27
90 55
45 27
Ω , and 4 Ω for
Ω .
Ω) for one foot of