Choosing The Correct Speaker Cabinets - Hartke TX300 Manual Del Usuario

Choosing the Correct Speaker Cabinets

When choosing a speaker cabinet to use with your Hartke TX300, there are many specifications
to consider (impedance, power handling, frequency response, etc). While most specs are pretty
straight forward, there is often questions about impedance. Basically, impedance is the amount
of current that will flow through a speaker at a certain voltage. It is measured in Ohms (Ω). The
actual impedance of a speaker is not constant across all frequencies. So, for convenience we
use the term "nominal impedance", which refers to the impedance that a speaker presents to an
amplifier at a reference frequency.
A typical speaker has an impedance rating of 4Ω, 8Ω, or 16Ω. Generally, the lower the impedance
of a speaker, the more power will be developed by a given amplifier. For example, a 4Ω speaker
will extract more power from your amplifier than an 8 ohm speaker. If you connect a speaker
with an impedance lower than the rating of the amplifier's output, the amplifier can overheat
and damage the power output section. It is important to learn how to connect multiple speaker
cabinets safely without damaging the speakers or the amplifier in this way.
Typically, amplifier speaker output jacks and speaker cabinet input jacks are parallel connections,
and will follow the rules described in this section. When speakers are connected in parallel, the
impedance is reduced. The formula to calculate the total impedance of your speaker system is:
If all speakers have the same impedance, the total impedance will be equal to the impedance of a
single speaker divided by the total number of speakers. For example, if you have two 4Ω speakers
connected in parallel, the total impedance is 4 divided by 2, or 2Ω. You must be careful when
connecting speakers in parallel to an amplifier. The impedance can quickly fall below safe levels.
This is especially true when connecting speakers in parallel to a bridged amplifier.
The amplifier can deliver 300 watts of power to a minimum 4Ω speaker load. When choosing
speakers, make sure that they can match or exceed the output power of the amplifier, or you can
damage the speakers.
TX300 - 300 Watt Bass Amplifier
1/R = 1/R + 1/R
t 1
Where "R" is the impedance of a speaker cabinet.
Typical Impedance Calculations
16Ω +
8Ω +
8Ω +
8Ω +
16Ω +
4Ω +
4Ω +
+ 1/R + ... 1/R .
2 3 n
16Ω = 8Ω
16Ω = 5.3Ω
8Ω = 4Ω
16Ω + 16Ω =
16Ω + 16Ω +
8Ω = 2.7Ω
4Ω = 2Ω
4Ω
16Ω = 4Ω
9