a fuse are you sure
i always though they were light bulbs

 

a fuse doesnt eat up power.. a fuse blows when it seems more surrent than it's rated at.. they're light bulbs.

 

It's a fuse in the circuit, it may glow like a lightbulb, and work like a lightbulb, but in this circuit it's called and reffered to as a fuse.
but for others it's a lightbulb.

It's a mulcher, it's a desert topping, it slices it dices and saute`.., heck it's a mulching desert topping !!

 

Yea.. I've seen fuses in home audio crossovers designed to protect woofers... these are a little different if you ask me...

Fuses have low resistance that stays relativly constant... these have a higher resistance that will increases as they get hot...

thats how they limit power, I presume...

 

I'm not sure why nobody understands how a light bulb works (AC or DC) and how an amplifer works and how they can interact with each other.

A light bulb has a voltage range it can work with to produce light from. What do amplifers do? They produce varying levels of voltage in the form of Alternating Current (AC). Okay, so the light bulb will light up when it sees a certain amount of voltage. The amplifier produces output voltage but is constantly varying with the transients of the music. The more you turn it up, the more voltage is produced. The more volts the light bulb sees, the more it produces light. A 12v lamp equates to quite a decent amount of RMS wattage that an amp can produce. As was said already, it burns off extra voltage that amp produces in order to save the tweeter. I had a system quite some time ago that when first installed would blow tweeters easily (the amp I had on them wasn't all that huge but I didn't want to turn the gains off and the xover point was fine). We put a light bulb on each tweeter circuit and the problem was solved. Did the tweeter sound disapper as the volume got high because of this burned off voltage? No. In fact it seemed to stay at a very nice level with them. Don't think they cause wicked dips or anything like that in your tweeter response because I have some personal experience to show that they don't.

Anyway, I just thought I'd throw some info in there about the topic. In short, don't worry about the blinking lights in your xover. They are a good thing for your tweets [img]smile.gif[/img]

 

I personally don't think you need em if you have mids and tweets that are properly matched with a crossovers.... but I guess they eliminate user error caused by overpowering (what about the mid?) or clipping... Plus it's got a cool factor... so thats all good....

But, a 5watt autobulb is going to be like 3ohms cool and 30ohms hot....

It's late and my brain is having some trouble here... but giving a 4ohm speaker system recommended RMS power with 9db of crest factor would give the bulb an average resistance well over 20ohms... it will only 'burn off' about 4watts of 160 available... but it will also decrease available amp power by more then 6db at the tweeters nominial impedance....

edit, BTW I figured all this considering that bulb resistance should be linear with input....

edit again.. for 60watts the average bulb resistance I get is around 15ohms for the 5w bulb & 9db CF...

[ September 13, 2004, 08:27 PM: Message edited by: Haunz ]

 

The Punch 5 1/4" component set is rated for 60 watts power handling (RMS). I am using a Pioneer 50 watts (RMS) amplifier. This should match the pair very well.

This is why I had the question in the first place. It seems a little odd that when the speakers are being fed with less than their rated power, the lights/protection is coming into play.

I wondered if this was just to add a little flash or pizzaz to their component set or if it protected the tweeter. It would appear that it does both.

Thanks,
Brad

 

more often you blow your speakers due to under-powering more than overpowering. An under powered speaker blows because you lose cone control and the voice coil heats up and seizes.
It takes a lot of juice to overpower a speaker to blow it, to the point where you might launch the cone accross the room. Hope this helps [img]graemlins/headbang.gif[/img]

 

[img]graemlins/jack.gif[/img]

 

Anyone know the acual value of these bulbs ?

I pulled the 5watt bulb in my example up there out of a hat...