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Useful information about transducers and small speakers
Transducers and small speakers are electromechanical components that emit acoustic signals. They are used, for example, as a buzzer or alarm notification for events. Miniature loudspeakers can not only play simple sound sequences, but also play back speech contents. The products in this category are still only used as functional loudspeakers, because they offer only a low sound quality due to their very compact design and can only reproduce certain sequences as sounds. The offer is therefore mainly aimed at hobbyists and professionals.
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How do sound transducers and small speakers work?
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This is important when selecting transducers and small speakers
How do sound transducers and small speakers work?
Sound transducers are electromechanical components. They convert electrical signals into acoustic signals.
The piezoelectric effect is often used as a converter principle: When current flows, the mechanical components change their shape. This deformation is transmitted mechanically to the transducer diaphragm, which produces an acoustic signal.
The following models differ in the complexity of sound reproduction:
Sound transducers in simple design can only produce certain sounds. These are continuous tones, interval tones or alarm sounds such as siren tones.
Speakers, on the other hand, can, as their name implies, also “speak”, i.e. play back incoming electro-acoustic signals in a comprehensible way.
Tip: The sound is generated by the oscillating air of a sound wave or by an electromagnetic field driven by a coil. The vibrating diaphragm of the acoustic signaling devices makes the respective vibration audible. In some small loudspeakers, the frequency oscillation is also technically amplified so that a humming or even a noticeable swinging of the entire component occurs, i.e. a vibration alarm.
This is important when selecting transducers and small speakers
Practical advice
Especially when space is limited at the desired location, micro-loudspeakers or electrodynamic acoustic components are preferred because of their compact design to use normal loudspeakers with good sound.
Basic questions for selection
When selecting a transducer or small loudspeaker, it is primarily relevant to the purpose for which you require an acoustic signal transmitter. There are three questions:
What sounds should the transducer produce?
Simple sound transducers only produce fixed sound sequences when an electrical signal is present. Speakers, on the other hand, can reproduce more complex voice signals in a comprehensible way.
How loud should the acoustic signal be?
Depending on the application, a rather loud or quiet acoustic signal is desired. The perception is largely related to the size of the area to be covered, the other background noise and the expected attention of the target persons. For example, a small sound pressure level is sufficient for electronic test setups, as the user turns to the signal at full concentration. Even battery warning tones do not have to sound very loud. For evacuation systems in larger rooms or entire building parts, however, a strong sound source is of course required. You can choose between 65 to 120 dB noise-reduction converters.
Where should the transducer or small speaker be installed?
When selecting the part, you should pay attention to the shape of the part and to the appropriate dimensions. In addition, you need sufficient space for cables and possible amplifiers. The mechanical fastening method also plays a role.
Note: Sound will be affected if the transducer is installed in a concealed way. Because then the sound waves cannot spread evenly.
Acoustic characteristics
Decibel is a logarithmic variable as an auxiliary unit in electronics and acoustics. It describes the perceived noise. Sounds from 0 decibels can be heard. The normal call volume is about 55 dB. With an increase of 10 dB, the volume is already doubled. The sound pressure level is measured using microphones.
The resonance frequency of a transducer tells a little about the wavelengths of the generated acoustic signals, which was in turn an influence on the range of the audible signal. The lowest available frequency of 4.5 Hz is a continuous tone generator. The highest frequency is buzzer. Sound waves between 16 Hz and 20 kHz can be heard by humans.
Electrical parameters
Surge converters as electrodynamic components have no fixed resistance, but an impedance that causes a phase shift between current and voltage due to the integrated voice coils. Impedances are also specified in the unit Ohm.
In addition to the permissible input voltage, the maximum load capacity in watts must be observed when selecting sound transducers and small loudspeakers.
Note: Refer to the specifications on the product pages and the related documents for download for details on each model.
Installation options
There are several options for the installation of transducers and small loudspeakers: For front installation or screw fixing, the housing of the signaling device is fixed mechanically. The electrical signals reach the input of the transducer via cables. The connection of the frequently open cable ends requires electrical expertise. For PCB transducers for PCB mounting, soldering techniques or plug-in systems are used.
Info: In most cases, a switch or a more complex electronic control is upstream of the transducer, which transmits an electrical signal when the signals are supposed to sound.
Tip: If a small speaker is to be installed, it requires an additional line at the input next to the power supply, which transmits complex audio content.