im sure most of you who have an aftermarket alarm must have at least one backup siren. so you guys may answer the following questions for me:
1. does adding more backup sirens mean less volum? e.g the 1st one you add gives out 12v when the 2nd and the third one are added, it's not gonna be as loud as one?

2. is it better off to install a backup siren inside or outside the car?

3. did you extend the key hole for the backup siren to an accessable but secured spot or it is still on the siren? i've asked two installers and they gave me two different answers, so im wondering.

4. should i put the brain in a hidden spot underneath the dash or there's a better place to hide it? im thinking about put it hehind the dash but not in the hood, possible?

it's great if you can answer me these questions.

 

1. The physics of sound don't follow conventional thinking...... I'll put it like this: a Marshall Full Stack guitar amp is only 6db louder than a Half Stack, yet you never see Jimi Hendrix, Jimmy Page, or David Gilmour use half of a Marshall Stack amp! (the full stack is considered just for show). Hence, two sirens aren't much louder than one. The only attribute of having two of them, you can mount one in the trunk, and have the sound in multiple directions.

2. You can install a 130db high frequency siren under the dash..... that way if someone acutally makes it into the car and gets under the dash to find all the wiring, they have this pizzo-electric buzzing painfully in their ear.

3. Refer to answer to #1.

4. That's the right spot.... hidden, difficult to access, and hide the wiring (loom and black tape everything, so you can't tell what is what!)

 

thanx fastball

refer to ur asnwer for question 4, did you mean the spot underneath or behind the dashboard?

 

most alarm brains are in the exact same place....under the dash on the driver side...its just easier for the installer...

heres some tips....somehow after the install mask all the wires black....dont put the sticker of the brand of alarm you have on your window...if the LED has the brand name on there, cover it.

all of the above gives clues as to which alarm you have.

2 sirens is good..the traditional under the dash, and another inside the cabin. there are sirens small enough to put inside of the vents, although that made block airflow.

 

thanx for the tips. one last question, does ur backup siren have custom external key hole for ease of access when you wanna shut it down?

 

back up sirens only go off when your original siren goes off. so if you disarm your alarm, the back up siren will turn off.

 

Oops! I meant under the dash. If you have the patience and are flexible you can get the box so far up the dash and out of the way, even you won't find it if you forget where you put it!

 

The only problem about mounting it there, is finding a good way to secure it so that it doesnt shake. I have to open un my dash and see how much space there is.

 

find a place to screw it onto...or use lots of zipties.

 

I would stay away from the battery backup siren, if you intentionally disconnect the main battery it will go off. This means you have to mount it in a vulnerable position so that you can use the key to shut it off. I would instead get a backup battery (DEI makes one) and maybe use two sirens. Hide them well (mines behind the fender) and loom the wiring. The battery backup continues to power the alarm after the main battery is disconnected. Don't stick the alarm brain under the driver's side dash, they'll rip it out in seconds.