Almost all of our speakers have the option to be delivered as 8 ohm, 20 ohm or with a transformer as standard products. You will notice that the speaker names in all of our datasheets have a (T) in them (e.g. HP-20 (T)). The T in our product names means that it is the transformer version. If you want to order a speaker in 8 ohm, you should omit the T (e.g. HP-20, 8 ohm). Our horn speakers can be customized in all kinds of impedances from 2 – 50 ohm or more.

Most of our products are available with different options for terminal block (e.g. ceramic), as well as with or without capacitor.

Ask us about specialities and modifications! We can for instance modify:

  • Color.
  • Cable Gland quantity, type and placement.
  • Volume control.
  • Cabling.
  • Transformer tappings.
First figure Second figure
0 No protection 0 No protection
1 Protected against a solid object 50 mm or greater 1 Protected against vertically dripping water
2 Protected against a solid object 12 mm or greater 2 Protected against vertically dripping water, when tilted 15 degrees
3 Protected against a solid object 2,5 mm or greater 3 Protected against water spraying at an angle up to 60 degree
4 Protected against a solid object 1 mm or greater 4 Protected against water splashing from any direction
5 Dust protected 5 Protected against jets of water from any directions
6 Dust tight 6 Protected against powerful jets of water from any directions
7 Protected against immersion between a depth of 150 mm and 1000 mm
8 Protected against submersion
Explosion Protection
An explosive atmosphere is built up by a mixture of flammable gases, vapours, mists or dust with atmosphere air.If the mixture (flammable material/air) has the right ratio it can be an ignition source and create an explosion. Factors for creating an explosion:
  1. Air (or in fact oxygen in the air)
  2. Flammable material (substance)
  3. Ignition source

There are two main principles to avoid an explosion; primary and secondary precautions.

Primary explosion protection can be achieved by (when an ignition source are present):
  • Using natural or forced ventilation to llimit the explosive concentration
  • Avoiding flammable materials (substance)
  • Using inert gas in the atmospphere (e.g. Nitrogen)

If still an explosive atmosphere can be created in a area it is only one way of avoiding explosion, Ignition Control

Type of ignition sources

  • Hot surfaces
  • Flames and hot gases
  • Mechanically produced sparks
  • Electrical equipment
  • Transient currents
  • Static electricity
  • Lightning strikes
  • Electromagnetic waves
  • Optical radiation
  • Ultrasound
  • Chemical reactions
  • People (indirectly)

Where do we find explosive atmospheres?

  • Metal surface grinding, especially aluminium dust and particles
  • Oil refineries, rigs and processing plants
  • Gas pipelines and distribution centres
  • Printing industries, paper and textiles
  • Aircraft refuelling and hangars
  • Chemical prosessing plants
  • Grain handling and storage
  • Sewage treatment plants
  • Surface coating industries
  • Underground coalmines
  • Woodworking areas
  • Sugar refineries
  • Vessels/ships
  • Power plants


Where a potential explosive atmosphere can occur, certain safety levels need to be taken into account regarding the possible danger of an explosion in this area. The areas therefore need to be devided into zones according to presence of the flammable materials. 

Zone 0 Zone 1 Zone 2
A place where the explosive atmosphere of flammable gas is present continously or for a period of frequently A place where the explosive atmosphere of flammable gas is likely to occur in normal operation occasionally A place where the explosive atmosphere of flammable gas is not likely to occur in normal operation, but if it does occur it will only be present for a short period
Zone 20 Zone 21 Zone 22
A place where an explosive dust atmosphere is present continuosly or for a long period of time A place where an explosive dust atmosphere is likely to occur during normal operation A place where an explosive dust atmosphere is not likely to occur during normal operation, but if it does occur it will be present for a short period
Typical concentration of gases in the air where an explosion can appear (% of gas in air):


Examples of the criteria for the mixture of flammable materials (gas) towards air in such a way that an explosion can occur are:
LEL Explosion UEL
Methane 4,4% 16,5%
Propane 1,7% 10,6%
Butane 1,4% 9,3%

100V Line speaker systems are sometimes referred to as “constant-voltage system” it is the most economical way to install a multi-speaker sound system. The term 100V system relates to the maximum output voltage of the amplifier. To generate this high voltage the amplifier is equipped with a step-up transformer, which increases the normal output voltage of around 30 Volts, up to 100 Volts

The main difference between a low-impedance speaker system (4 or 8 Ohms) is the way the individual loudspeakers are connected to the amplifier, with the conventional low-impedance system special care has to be taken to maintain the correct impedance for the amplifier.

In a 100V line system, a large number of single loudspeakers each equipped with a step-down transformer can be connected to one single speaker cable. With the 100V line installation, each speaker or speaker cabinet is equipped with a step-down transformer

A step-down transformer has relatively high impedance at the primary side and the secondary side of the transformer matches the speaker impedance (typically 8 Ohms). The primary side of the transformer normally has several tapping’s, these are marked in watts and are used to enable each speaker to be set at different volume levels. The total primary wattage should not exceed 90% of the amplifiers output. A step-down transformer will be required for each loudspeaker cabinet connected to the amplifier.

Search across our wide range of loudspeakers, from industrial to commercial applications.