Use a light bulb to protect your panels

[ScottGardner]

Since I bypassed the passive Xover in my Aerius I's I've been worried about the panels. I was using an external digital XO that has built-in limiters but I have since removed that.

Someone on the RME site pointed this out:

http://www.eden-electronics.com/info/articles/tweetertext.htm

It says the best approach is to use a calibrated light bulb!

Anyone heard of this?

I'm going to try it and see how it sounds.

 

[Audiophiliac]

This isnt a direct response to your query, but the crossovers for my car speakers have a light bulb in them to protect the tweeter.

 

[ScottGardner]

The link I gave above does actually talk about protecting tweeters. Maybe the panels are not as fragile.

Still the fact the light bulbs act as limiters when the current gets high and shows this action by lighting up would serve as a visual indication that the panels were being pushed too hard. (that is if the proper wattage bulb is being used)

 

[Tj Bassi]

Interesting, but I havent found much info on calibrated bulbs.

The average tungsten filament light bulb has a fairly high filament temperature coefficient....there is a huge inrush current when first energized but the (quickly) rising filament temperature throttles that current way down. I recall a project from some years ago where we were designing labroratory heater controllers and were using bulbs to simulate the heater loads....the bulbs were good loads if used at close to their rated wattage but not very consistent at low current levels....leading me to believe that the filaments are not manufactured to tight specs....other than to have the proper temp co to prevent premature burning out (the 'fuse' as mentioned in the article).

If you find more on the 'calibrated bulb' theory please follow up.

Tj

 

[nsgarch]

The link I gave above does actually talk about protecting tweeters. Maybe the panels are not as fragile.

The issue is not that panels aren't fragile, they're simply not an electrodynamic device. A lightbulb won't protect an electrostatic device, which is basically a capacitor through which no current can flow (they can only charge and discharge yummy!)

JBL still builds lightbulbs into their little pro monitors to prevent overloading the dome tweeters.