www.madmaxmovies.com

OUT-FUCKING-STANDING!! I followed this build from its inception, and honestly did not think you'd get this close to authenticity... Seeing the film screenshot and yours side-by-side a few pages back seals the deal. Great job!!

Hey, thanks, Soulblinder! Comments like that from the real fans truly make my day!

Uncle Drax, it may be the computer that I'm using, but I can't see the pictures you mentioned. I'd love to see a bird's-eye view of us out there.

Next up for The Machine is the November Road Warrior Weekend Event in Cali, then then February Detroit Autorama, and then the May Motor City Comic Con (with Bruce Spence!) here in the Detroit area.

Be there!

HUMVEE Driver

Nevermind, Uncle Drax, I see it.

Very cool; thanks for sharing!

HUMVEE Driver

Is there anyone out there with experience in installing vehicle PA systems? My original PA system plugs into the cigarette lighter and it's not as loud as I want it to be. Also, some people said that when I did the Humungus speech I sounded garbled. So (for better clarity and more volume) I bought a top-of-the-line emergency vehicle radio thing with a PA switch, and I tried hooking it up to a 100 watt speaker. This system is wired directly to the battery. I don't have it wired up yet, but I'm hoping to find someone who knows about this stuff and can give me some pointers. I tried contacting numerous car audio places and they weren't any help.
So, help!
HUMVEE Driver

You got an ex-sparky (electrician) here.

Rule one, make sure you use a fuse between your battery and PA. If you don't have a fuse panel, use an inline one.

If your 'car' has a negative earth (the battery negative connects to the chassis), then you only need to run the red wire from the positive to the PA, then connect the PA negative to the body.
You'll need two wires to the speaker(s)

As for the sound being muffled, that is usually a result of
a)holding the mike too close to your mouth (it should be about 1 inch away)
b)putting too much volume into the speakers

In my case, I use 3 speakers to distribute the sound.
umm...did I cover everything, or did I miss the point entirely?

Hey thanks Daz! I've got the wiring all taken care of. (My Dad's an ex-sparky too and he's been helping me with the wiring.) We have a fuse in there and we are checking to make sure that what is hot is supposed to be and vice versa. I guess I'm wondering about the volume (or lack thereof) and the power source. Will I get more power/volume from a system wired right to the battery vs one that is plugged into the cigarette lighter? Will a modern 'radio' work with an older speaker? (That is my current set-up.) Is there any way to make it louder?

HUMVEE Driver

HUMVEE Driver wrote:Hey thanks Daz! I've got the wiring all taken care of. (My Dad's an ex-sparky too and he's been helping me with the wiring.) We have a fuse in there and we are checking to make sure that what is hot is supposed to be and vice versa. I guess I'm wondering about the volume (or lack thereof) and the power source. Will I get more power/volume from a system wired right to the battery vs one that is plugged into the cigarette lighter? Will a modern 'radio' work with an older speaker? (That is my current set-up.) Is there any way to make it louder?

HUMVEE Driver

Only the US call positive, hot. Aussies call it positive. If on the 240v on a house, we call it active, ouch, or $%@^&*^$

A cig lighter socket will provide about 15 amps. Direct to the battery, you can pull 300amps(for short periods, like when starting).
Realistically, it will make little difference in your set up, unless your blowing the cig lighter fuse.

However, the loudness is determined by the amount of watts the radio can output. 20W is normal for a car stereo. To get louder than that, use an amplifier. A quick ebay search shows some for $50 that can do 200w RMS.

battery->radio->amplifier->speaker
|
battery -------------

If you are using a PA, some of them use a step up transformer, making the amp no good. If youre jury rigging a salvaged PA from a building, that may be the case.
The speaker also makes a difference. What are you currently using?

240v in a house? Wow, is that standard? You can get that over here, but I'm pretty sure most US homes are 120v. Ok, back on topic...

The 'radio' (or siren) I'm using is a professional one made for fire trucks or police cars. You have a knob for three different types of sirens, the PA itself, the airhorn, etc. So I know it has to be loud as #@$%.

Here is a link to it:

http://www.galls.com/google/style.html? ... tyle=SK124

The speaker is an old one, but it's labeled 100 watt. I tested it beforehand by putting the wires to a car battery and I got some static, so I know it works. I'll try to take a picture of it.

I had the whole thing hooked up and got nothing, then I took a close look at the diagram and realized I needed to splice in one of the positive wires. So this Sunday I'm going to do that and see what happens. I'll let you know.

Now, say I get it working... how long can I talk before killing the battery? Humungus' speech is only about a minute and thirty seconds.

I really appreciate your input! Thanks!

HUMVEE Driver

DONOT CONNECT 12v TO YOUR SPEAKER! SEE BELOW

Yeah, USA is 120v (it gives you a tingle), and Oz uses 240v (bites like a funnel web spider). 3 phase is fun, as is the 400vdc used on ships and trains. You don't get a second change with that.

That looks like a good siren unit, I can see it's rated at 100 watts output. First of all I would suggest using a horn speaker, not a 'normal' car speaker.

Something like:
http://www.galls.com/google/category2.h ... g&cat=2660
Or find a cheaper one or two on ebay that are 100w.

Being that they sell that, and it is rated at 100watts (the power it draws),and 120db (I guess it's actually a little less than that, as manufacturers over estimate the figure -120db is the noise of a jet taking off at 60 ft.) it will be about as loud as a car airhorn. Yeah, people will hear your voice.

I'd say go for a speaker like that. I have 3 like that mounted in my grill to get the noise out:-)

Looking at the wiring diagrams on their site:
http://www.galls.com/DOCUMENTS/SK124_Ga ... _ST160.pdf

You basically supply power to the siren.
Then run 2 wires from the unit to the speaker. The speakers should not be connected to 12! the unit will power them.
Personally, I'd use either the lighter socket, or run it from the accessory line, so that you need the engine on to use it. Otherwise you may forget and leave it on, and flatten your battery.

Battery goes to pins 1 and 2.

Try that, and the unit should light up.
Next, connect the speakers (brown wires) goes to pins 7 and 12.
Try that, and it should work!
You only need 4 wores for the basic PA use. Get that working the we'll attack the rest.

I'd say you'd be able to use it almost indefinatly with the engine running, or about 1-2 hours with the car off.

Too bad your not in Oz, otherwise I'd say to come over and we'd knock it over in an hour then have a few beers.