Choice of power and speakers cable
The following system for calculating and identifying the cable is not the most "right", many companies (not
only in the audio sector) have their own standards to determine the right section of the conductors, it
depending on the destination and the temperatures of use etc.
However, using this table, it can be almost guaranteed that the maximum voltage loss does not exceed 0.4V
if you pay attention for connections and if we consider a standard quality of copper.
Calculation of the POWER cable section:
-
Once you have chosen the amplifier configuration (stereo, mono, multichannel etc.), add the total
RMS power which we will call "
PotRMS
".
-
Choose the working voltage, normally you opt for 13.00 "
Volt
".
-
Estimate the efficiency "ŋ" that is normally valid:
50% AB class amplifier in stereo @ 2 Ohm (or bridge mono @ 4Ohm)
60% AB class amplifier in stereo @ 4 Ohm
70% D class amplifier
Finally we perform this simple calculation:
PotRMS
/
Volt
/ (
ŋ/100)
=
Ampere
And we will find the necessary current in
Amperes
, using the tables on the next page we identify the
necessary cable section, as shown in the following example.
Example:
Power RMS = 125+125Wrms=250Wrms=”
PotRMS
”
Voltage = 13,00 “
Volt”
Efficiency = 60% = “
ŋ
”
Perform this calculation : 250/13/(60/100)= 32
Ampere
Now, watching the “POWER CABLE SELECTION” table on the Appendix A, we identify the closest value that
includes our value (32 Ampere) in the “REQUIRED CURRENT” column, so let's take the “40A” row. For
example, if you have to install the amplifier with a cable 4 meters long for the positive and 1 meter for the
negative (total 5 meters), the column to be crossed is the one marked "5m". This intersection shows a value
of 13.33mmq which, watching the table “CONVERSION AWG <> mmq”, it meet the AWG = 6.
Calculation of the SPEAKERS cable section:
I
=sqr(
P
/
R
)
Where
I
is the required current
sqr is the square root operation
P
is the power (rms) delivered to the speakers
R
is the impedance of the driven system
Example:
Power delivered
P
=500W
Impedance of the system
R
=2 Ohm (example a couple of woofer that has 4Ohm impedance installed in
parallel)
We'll have
I
=sqr(500/4) so the current is
I
= 11,1 A
Audio Solution - Flagship user manual v.14
23
Summary of Contents for FLAGSHIP M
Page 1: ...FLAGSHIP M manuale utente ITALIANO 2019 2021 Audio Solution Flagship User Manual ver 1 4 ...
Page 7: ...Fig 3 SCHEMA CABLAGGIO Audio Solution Flagship user manual v 14 7 ...
Page 14: ...FLAGSHIP FLAGSHIP User manual ENGLISH Audio Solution Flagship user manual v 14 14 ...
Page 19: ...Fig 3 WIRING DIAGRAM Audio Solution Flagship user manual v 14 19 ...