siren inside the vehicle?

Nobody pays attention to car alarms in public. The last time I installed a car alarm in one of my own vehicles, I decided to use that 120 dB to my advantage. I stuck the siren up behind the steering column, firing downward with the wiring loomed in with the rest of the car's stock electrical system... And there's a lot up in that neighborhood... Fuse box, Gauge Cluster, Ignition wiring... It woulda been hell to trace anything down to cut the alarm off. I hide a little 12v backup battery up behind the gauges. If some b*stard wants to steal my stereo, he sure ain't gonna be hearing it any time soon. Basically, in addition to attracting attention, which never happens, I like to use the siren as a deterrent. How long can someone stand sitting in an enclosed vehicle with a siren in their ear? I'm kinda sadistic when it comes to thieves. I think they deserve it. Whaddya think? Anyone else put the siren inside the vehicle? Off topic: I also like to backstrap my head units and fill the heads of the screws in with solder or RTV sealant. Basically, if you're gonna be ripping the stereo out, it's gonna be useless because you're more likely gonna rip that amplifier heat sink off of the rear of the head unit. I use heavy duty pipe strap from Home Depot for backstrapping. I usually bend it off rather than cutting it nicely so there's lots of nice sharp edges up behind the head unit. Once, I even glued some razor blades to the back of the head unit.I zip tie the wiring away from the sharp edges. If the head unit has an external DC/DC converter like my old early 2000's Kenwood KMD-X92, I tie that somewhere away from the unit. Worked out well in a buddy's Corolla. He had the same unit. It got stolen because there was nowhere to backstrap it... Too much plastic ductwork. I've personally never had anything stolen. I hope nobody ever does either. The blood will be a pain to clean up.

I thought it was a common practice (or recommendation) for internal sirens for any alarm system - whether domestic or car (with a ramp-up!). The exception is when you don't have insurance to cover for willful or negligent hearing damage. Razor blades here would probably be considered criminal the same as broken glass and sharps on fence tops etc. That is intentional damage - not deterrence. I would only use it if bloodied blades triggered some accidental explosion that negated any chance of law suit or revenge. I have a few web-cams inside my cabin. All angles are covered. I risk a fire bombing etc if discovered too late, but hopefully the strange real-time antennas means they'll simply cut their losses and leave.

Internal sirens are an old but wonderful idea.

I wish my airbags would deploy when my siren goes off and a pressure sensor on the seat is active. Hopefully it will teach the thieves if not knock them out.

What a coincidence! It must have been the forced entry or wiring disturbance that set the bags off! I can just imagine them KO'd - head or legs on the rear parcel tray. LOL!

if you place a siren inside, what you would want is a piezo siren that is small and loud. Just hide that under the passenger side and always carry some ear plugs with you incase you need to use the valet switch. they are really loud