Aftermarket Car Alarm.. Want to make it louder

[Matt G]

Anybody know a good car siren? Not the whole system just the siren. My car has a 740T Hornet Siren.. it is loud but I don't think its loud enough.. If I'm inside my house and it goes off I can't hear it.

[CAMAROWIDBASS]

go with multiple sirens, or if thats not loud enough get a train horn.

[Matt G]

Originally posted by CAMAROWIDBASS:
go with multiple sirens, or if thats not loud enough get a train horn.

should i just splice the positive and negative?

If I splice it I think I might run into difficulties.. the wire is very thin

[CAMAROWIDBASS]

noo you just cant splice into the wire, you have to use a relay.

[Matt G]

I am pretty new to wiring, can you explain what a relay is, where i can pick one up and how much it would cost

[CAMAROWIDBASS]

how many more sirens do you plan on adding on?

*some* alarm systems can handle up to 2 sirens total when you wire them in series.

Relay is like anywhere from 99 cents to $3.00 depending on where you get it.

If you want to go all out like me on my camaro i have 4 exterior sirens, and 2 interior mini piezo sirens. Then you will need a heavy duty relay, more like $5.00 or so.

[Matt G]

where do you have these exterior sirens? I have one siren now inside my engine bay, I would like to add another one on the opposite side of the bay and see how loud it gets

[Matt G]

okay went to radio shack today, asked the manager what kind of relay i should get to run another alarm off of and he tells me i shouldn't use a relay.. i should go through the brain,
but i don't think he has any idea what he is talking about please tell me what voltage and what kind of a relay i should get

[CAMAROWIDBASS]

its just a regular 12 volt relay, you can get them at auto zone.

You know like the type of relays in your fuse box, like that.

[nda0602v6]

HERE is a link to a (30-amp) 12volt automotive relay.

Check your alarm (brain) and see if it has aditional output triggers or see how many aditional sirens can be hooked up to the main "siren output." OR You can just wire up multiple sirens using a relay because the sirens will draw their power from the relay's power source instead of the brain....all the alarm brain will do is activate the "relay" which in term sends current to the siren(s). If you're going to use a relay, I'd recommend using a relay SOCKET. Just makes it easier to wire instead of working with those little terminals on the relay.

[nda0602v6]

Here's one way to use a Relay to power multiple sirens. If you wire it this way, make SURE the "siren output" coming out of the brain is in fact a (+) output. Also, make sure to fuse the Relay's power source.

[Matt G]

There are 3 wires that go to my siren, red & white(pos + neg) and a green which i imagine is the wire running from the brain.. if i'm right is the green wire a positive/negative brain wire


...and if its not a wire from the brain what is it?

[nda0602v6]

Your alarm should've come with some type of wiring diagram which gives the color codes and functions of each wire going to the brain. What's the brand name of your alarm system?

[Matt G]

hornet 740T, i have a manual.. just have to look for it, think its in my room somewhere

[CAMAROWIDBASS]

I feel sorry for the sucker that breaks into my car, i just got a hold of 2 air sirens along with a 12V 40A compressor. I just tested it to make sure it worked and damn is it loud.

Ill take it to my installer this weekend so he can put it in. :D