Meyer Sound Ashby-5C Operating Instructions Book Manual page 8

CHAPTER 2: CONNECTING ASHBY LOUDSPEAKERS
Cable Length and Gauge
The maximum cable length depends on the type and number
of speakers looped and the gauge of the cable. Table 1
shows the maximum cable length for Ashby speakers 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 speakers are
installed. The maximum number of speakers shown in
Table 1 results in a maximum 3 second average power
within Class 2 wiring limits in most countries.
Using 18 AWG wire, a single Ashby-5C loudspeaker can use
up to 450 ft of cable (300 ft for Ashby-8C) from the Power Sup-
ply and lose no more than 1 dB of peak SPL. Unlike 70 V line-
distributed speakers, Ashby speakers do not suffer gain loss
with the long 18 AWG cables.
Table 1: Maximum cable length using 18 AWG cable
Model Number of
Speakers
Ashby-5C
Ashby-8C
Table 2 shows the maximum cable runs for a single channel of
an MPS-488HP 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
speakers using four wire gauges (AWG)
Maximun Cable Length (ft)
Number of
Model
Speakers
1
Ashby-5C 2
3
1
Ashby-8C
2*
*Applies to one Ashby-8C with one looped Ashby-5C
8
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
speakers using four wire gauges (m)
Number of
Model
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
speaker and its external power supply is 6
Ashby-8C.
When using the maximum number of speakers per channel (2
Ashby-5C or 3 Ashby-8C), it should not exceed 2
18AWG
Calculating the Maximum Cable Length
0.00636
Ω
( /ft)
The maximum cable length for an Ashby loudspeaker can be
calculated using the formulas shown below. The Wire Resis-
450
tance Per Foot (WRPF) is the resistance (in
225
individual wire of the chosen gauge. Enter the WRPF in the
equations below to determine maximum cable length. The
150
equations compensate for round trip length.
300
For 18 AWG, WRPF = 0.006385
150
Ashby-5C: Maximum length (ft) = 3 / (WRPF x # of Ashby-5C)
Ashby-8C: Maximum length (ft) = 2 / (WRPF x # of Ashby-8C)
To calculate the maximum length in meters, substitute the
Wire Resistance per Meter for the selected wire gauge.
Some high frequency loss can occur
Maximun 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 one
Ω .
Ω) for one foot of