Twin Alert

The Twin Alert is a unique product which combines both speaker and sounder elements in one single unit. The speaker enables keypad tones and setting mode to be heard, and benefits from an independent volume control. If more than one Twin Alert is to be used, then the volume can be independently adjusted according to customer requirements. The speaker has a 300 Ohm impedance, enabling more than the usual two 16 Ohm extension speakers to be fitted to a system.

The sounder provides a high volume internal siren, over-riding the speaker volume control when activated. This acts as a high pitched deterrent to intruders and an unmistakable warning siren to inhabitants, having a peak sound output in excess of 100dBA at one metre.

Both the speaker and sounder elements are manufactured using piezo ceramic, making this unit more hardwearing than a traditional speaker. The Twin Alert is housed in a robust ABS 3mm thick case, with a five-way cable entry for ease of installation and can be either ceiling, wall or corner mounted.

By installing the Twin Alert rather than individual speaker and sounder units, cost savings can be made both in terms of the purchase price and the time required on site.

What our experts say ...

Most currently produced intruder alarm panels provide an output for the connection of a loudspeaker to give exit/entry and alarm conditions, plus a separate switched 12v output for powered sounders. Often during a genuine activation the loudspeaker alarm output is insufficient to have a deterrent effect. Up to now the only alternative has been to fit both a loudspeaker and a powered internal sounder, such as a sound bomb. Unless great care is taken with siting, in a domestic installation this can end up looking untidy.

Pyronix has come up with a clever solution in the form of the new Twin Alert, combining both an extension speaker and piezo sounder in a single housing. It also has the advantage of being cheaper than two separate units, which cannot fail to please every installer!

Features

The Twin Alert is a combined internal speaker and sounder designed for use with intruder alarm systems having both a loudspeaker output and a switched 12v output for a sounder. The unit can be configured using removable jumpers for positive or negative switching, and copes with eight or 16 Ohm speaker outputs.

The supply voltage tolerance is from 9v to 14.5v DC, and the Twin Alert consumes 30mA quiescent and 160mA in alarm condition. Sounder output from the piezo element is 100dBA at one metre, and the loudspeaker output has an on-board volume control for exit and entry tones. A lid tamper switch is fitted. Twin Alert carries a two year warranty.

Construction

The Pyronix Twin Alert housing is moulded from white 3mm thick ABS with a removable cover secured by two screws, and has a double-sided PCB with discrete components of mixed surface mount and wired construction.

It is of circular shape in plan view of 90mm in diameter, and 46mm in height. The team considered the design to be rather odd, with opinions divided as to its looks. As with all Pyronix products the board is neatly packaged, but the small terminal blocks, jumpers and connectors can be somewhat fiddly for chubby fingered engineers. Dismantling the unit causes a problem, as the small pozidrive headed screws are deeply recessed, making the correct sized screwdriver imperative. Unfortunately not many engineers have a size 0 pozidrive screwdriver in their toolkits, but the ubiquitous slightly rounded terminal driver that all engineers carry can probably do the job!

The case has three cable entry tunnels at the rear, plus various knock-outs for side and rear cable entry. Cable strainers are provided, and well moulded lugs locate the PCB securely and positively. The case also features 45 degree chamfers on all four sides, although it would be unusual to have the unit fitted in a corner.

Performance

The unit was Bench Tested by the panel, and performed well. The independent volume control for the loudspeaker part of the unit is very useful, as it allows the exit/entry tones to be adjusted separately from the control unit. The internal sounder produced a high pitched piezo noise, sufficiently loud to make any intruder retreat from the area.

The piezo element is mounted in the lid of the Twin Alert, and is connected to the PCB in the base of the unit by a flying lead and mini-plug connection. Unfortunately the leads are rather short, which resulted in a member of the test team managing to rip one of the connections from the piezo element while trying to dismantle it.

This was probably more to do with ham-fistedness than poor design, but nevertheless could be a problem on site if a spare were not available.

Having dismantled the unit, we found on re-assembly that it is possible to insert the PCB in the wrong orientation, which means that the PCB mounted tamper switch does not come into contact with the projecting lug on the case lid, as the lid only fits in one direction.

However this only a niggle and is unlikely to go un-noticed, as by fitting the PCB back to front the cable strainers are opposite to the terminal block.

Instructions

Pyronix has always provided clear, simple graphics-based instructions with all of its products, and the Twin Alert is no exception. Dimensions, layout, mounting and connections are illustrated, with text and tables covering installation, connections and jumper selection.

A useful table covers connections to all popular panels including Scantronic, Ademco, Menvier etc. Mention is made that multiple units may be connected, but one omission is that no mention is made of how speaker impedance is affected. Should the speaker side of the unit be wired in parallel or series?