SPS Series

Sonitron Polymer/metal Speakers (SPS) produce high sound quality with low distortion and guarantee the perfect reproduction of music and speech. They have a very flat design and are delivered with an open front. They can be used in difficult environmental conditions and applications because of resistance of the front to water, humidity, vibrations, and dust. Piezoceramic speakers feature a low weight and low energy consumption relative to their sound output levels. They do not generate an electromagnetic field, making it easier for designers to ensure that their products meet EMC requirements and regulations.

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  • Very flat and solid design construction 
  • Dust, water- and shockproof
  • Resistant to temperature variations 
  • Broad frequency range in small size 
  • Combined use as speaker/micro
  • no electromagnetic field (EMC) 
  • Little energy required at low frequencies
  • Less current consumption needed in the leads to the speaker 
  • 60% higher acoustic output for smaller speakers compared to electrodynamic speakers 
  • Low weight
  • Low distortion 
  • High impedance
  • Can be driven directly by IC
Home EquipmentCommunication equipmentTalking buzzer & doorbellComputer equipment 
Cars, busses, and trains Vending machinesIndustrial equipment Portable voice recorders 
Paying systemsMobile phone Car audio system






ModelOperating voltage

( Vac pp)

Frequency range (Hz)Max SPL

(dB @1m, average 4 points)

ApplicationsCapacitive loadDimensions mm (LxWxH)
SPS-2220-031-24700-2000085*GSM, GPS, MP3, camera,…70nF22x20x2
SPS-3530-035-60700-2000081PDA,GPS, notebooks,…220nF43.5x39x2
SPS-4640-035-60400-2000083PDA,GPS, notebooks,…225nF50×43.6×2
SPS-8770-035-60200-2000084Computers, …580nF87x70x2


*@10cm, designed for headphone applications!



Theoretical the main impedance of the piezo speakers is a capacitive reactance and follows an asymptotic function.



The typical practical impedance values (+/- 20%) for frequencies of 100Hz up to 20kHz of our speakers are as follows:


Capacitance (+/-20%)70 nF220 nF225 nF225 nF580 nF
Z @ 100 Hz22360 ohm5714 ohm6210 ohm3845 ohm2314 ohm
Z @ 1 kHz2162 ohm603 ohm680 ohm445 ohm266 ohm
Z @ 2 kHz1183 ohm311 ohm360 ohm223 ohm133 ohm
Z @ 5 kHz497 ohm127 ohm143 ohm92 ohm54 ohm
Z @ 10 kHz245 ohm65 ohm73 ohm45 ohm28 ohm
Z @ 15 kHz168 ohm43 ohm49 ohm31 ohm19 ohm
Z @ 20 kHz125 ohm32 ohm37 ohm23 ohm14 ohm




Sound pressure level vs. frequency




Dimensions ( All dimensions in mm) 








Product codification 


List of available products 




Mounting guidelines 

The SPS speakers can be mounted in several different ways. The mounting methods illustrated below are recommended to mount all the SPS speaker models. Please keep in mind that not too much mechanical stress is placed on the frame of the piezoceramic speaker after mounting.







Important note:

Piezoceramic speakers produce sound by the forward and backward movement of a flat membrane. During this movement, the membrane creates an air pressure wave in front and at the backside of the membrane. A forward movement will create a slight overpressure at the front side and a slight underpressure at the backside and vice versa. It is therefore important that the front and backside are acoustically isolated from each other to avoid air pressure cancellation and consequently a serious reduction of the sound output.



When a speaker is mounted in a panel or in the wall of a housing, the front side is acoustically isolated from the backside.