The 5 most important parameters of a Speaker

Understanding the characteristics of a car speaker is of paramount importance when setting up an automotive sound project. It is based on these characteristics that we will know more precisely the power and frequencies that the speaker will be able to convert into audio through its structure.

In this post we will cover the 5 most important parameters of a speaker explaining in detail what is the function of each one so that you understand a little more about the functioning of a speaker and do not choose the wrong model for your project.

1 - Power:

As it couldn't be different, the power is one of the most important parameters when choosing your speaker, after all, nobody would buy a speaker without first knowing its power, right? Power is measured in Watts RMS and is nothing more than electrical energy transformed into sound waves.

Mistakenly, many enthusiasts and even manufacturers give the power information in PMPO which is completely erroneous since the PMPO power can be a value far beyond the real power (RMS) of a speaker. Therefore, never take power into account in PMPO, but in RMS.

2 - Frequency Response:

Every speaker has an operating frequency range. This name is called the frequency response. In the case of woofers and subwoofers , as they are large speakers, their function is to emit low frequencies (sub-bass, bass and in some woofers, medium-low).

The drivers emit medium-low frequency, medium-high and in some cases even treble. And super-tweeters only emit high, high frequencies. If we look at any manual, the frequency response has two values ​​measured in Hz (Hertz), initial range and final range of response.

These are the values ​​that the speaker can emit at the minimum and maximum frequencies respectively. For example, if a speaker's manual says that the frequency response is 50Hz to 1000Hz (or 1kHz), it means that the lowest frequency it emits is 50 Hertz and the highest frequency is 1000 Hertz.

3 - Sensitivity:

Sensitivity is a measure of the electrical signal sent to the speaker and the sound pressure that was obtained from that signal. Most manufacturers do the tests with 1 Watt of power at 1 meter of distance through a pink noise (very similar to the “hiss” that TV's make when there is no signal). This measure is called decibel (dB).

If you look at the speaker manual, it will be there as follows: Sensitivity 1W @ 1m: 94dB SPL. This means that your speaker propagates 94 decibels with 1 Watt of power at a distance of 1 meter.

For comparison, a normal conversation between two people emits a sound power around 60 dB or a rock show that emits something between 120 dB. We warn you that it is not recommended to be exposed to frequencies above 85 dB (mainly at high frequencies) as it can cause serious damage to the ear.

4 - Impedance:

As we previously explained in another post ( see here ) impedance is the sum of the 3 resistors [electrical (coil), magnetic (interaction between the coil and the speaker magnet) and mechanical (spider and cone suspension)] that a speaker faces when it receives the electrical signal from the amplifier.

The unit of measurement to represent the impedance is the word Ohm (symbol: Ω) which is the unit that measures the electrical resistance of a conductor or resistor standardized by the SI (International System of Units).

5 - Resonance frequency:

As we saw in item 2, each speaker has a frequency range in which it operates. Depending on the speaker, the efficiency of emitting a given frequency may be greater than another. This is called the resonance frequency, that is, it is the frequency that the loudspeaker emits most efficiently (highest response).