Difference between revisions of "FAQ about audiological issues"
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==What is meant by speaker sensitivity?== | ==What is meant by speaker sensitivity?== | ||
| − | Speaker sensitivity is the level produced by the speaker at one meter distance, when supplied with one watt of power from an amplifier. It’s a way of describing how well the speaker produces acoustic energy, based on a given input. The level is measured in dB SPL – this shorthand for ‘sound pressure level’ – sound is basically fluctuations in air pressure, so any time you see SPL, this means ‘sound in the real world’. So, let’s say we have a speaker with an 87dB sensitivity, and a speaker with a 90dB sensitivity – the 90dB speaker is going to be considerably louder, as every 3dB added represents a doubling of power. | + | Speaker sensitivity is the sound level produced by the speaker at one meter distance, when supplied with one watt of power from an amplifier. It’s a way of describing how well the speaker produces acoustic energy, based on a given input. The level is measured in dB(SPL) – this shorthand for ‘sound pressure level’ – sound is basically fluctuations in air pressure, so any time you see SPL, this means ‘sound in the real world’. So, let’s say we have a speaker with an 87dB sensitivity, and a speaker with a 90dB sensitivity – the 90dB speaker is going to be considerably louder, as every 3dB added represents a doubling of power. |
The sensitivity of a speaker is often specified for a 2.83Vrms input signal. This is because this equals one watt of power when the impedance of the speaker is 8 Ohm. | The sensitivity of a speaker is often specified for a 2.83Vrms input signal. This is because this equals one watt of power when the impedance of the speaker is 8 Ohm. | ||
Latest revision as of 10:25, 23 November 2023
What is meant by speaker sensitivity?
Speaker sensitivity is the sound level produced by the speaker at one meter distance, when supplied with one watt of power from an amplifier. It’s a way of describing how well the speaker produces acoustic energy, based on a given input. The level is measured in dB(SPL) – this shorthand for ‘sound pressure level’ – sound is basically fluctuations in air pressure, so any time you see SPL, this means ‘sound in the real world’. So, let’s say we have a speaker with an 87dB sensitivity, and a speaker with a 90dB sensitivity – the 90dB speaker is going to be considerably louder, as every 3dB added represents a doubling of power.
The sensitivity of a speaker is often specified for a 2.83Vrms input signal. This is because this equals one watt of power when the impedance of the speaker is 8 Ohm.
In the case of headphones the sensitivity is expressed in dB(SPL) per milliWatt input power (dB/mW).
What is impedance?
You will often see impedance mentioned when researching speakers, and amplifiers. Impedance is basically resistance measured at a given frequency, given as a value in Ohms (Ω), and is incredibly important to consider when setting up an audio system as it determines the ‘load’ placed on an amplifier by the speakers. For example, let’s say we have an amplifier that is rated to deliver 100W into an 8Ω speaker load. If we were to then use speakers with an impedance of 4Ω with the same amplifier, the amp would then need to supply 200W as a halving of the impedance results in a doubling of the required power due to the reduction of the load on the amplifier. In a situation such as this, if the amp can’t supply the required power for a lower impedance, then it can result in overheating, and damage to the amplifier and speakers. For this reason, it is important to pay attention to amplifier specifications, and suggested impedance ratings.