So, I have this CRAZY idea (It's crazy!) for a little more juice from the stock system...

According to Oliver Shultz, the stock amp is 20 watts, I assume that would be average (RMS). I dunno if this is accurate.

The replacement I have from Rodney is capable of 60 watts RMS and is 8 ohm.

Now, I would like to get more power from the stock amp, and assuming the stock subwoofer was also 8 ohms, the only way to do this would be to lower the resistance of the new subwoofer.

For instance, if I wanted to triple the power from 20 watts RMS (stock) to 60 watts RMS to match the new speaker, I would have reduce the new subwoofer's resistance to 2.666666 ohms, which is one third of 8 ohms. I could do so by wiring a 4 ohm resistor between the terminals of the subwoofer, (putting it in series).

So, to recap, my questions are, what is the stock subwoofer's resistance, and, what is the stock amp's power rating?

And if the answers to the above are 8 ohms and 20 watts RMS, would soldering a 4 ohm resistor between the positive and negative poles on the subwoofer provide the desired result? Or would there be a small explosion in my interior followed by fire and lots of pain?

------------------
Thanks Aus!
More info at: https://www.fiero.nl/forum/Forum1/HTML/043357.html

Most of these speakers are 10 ohm impedance ,why not just use a 4 ohm and you would be good to go .

Because my Rodney sub is 8 ohm.

quote Originally posted by Bigfieroman: So, I have this CRAZY idea (It's crazy!) for a little more juice from the stock system... According to Oliver Shultz, the stock amp is 20 watts, I assume that would be average (RMS). I dunno if this is accurate. The replacement I have from Rodney is capable of 60 watts RMS and is 8 ohm. Now, I would like to get more power from the stock amp, and assuming the stock subwoofer was also 8 ohms, the only way to do this would be to lower the resistance of the new subwoofer. For instance, if I wanted to triple the power from 20 watts RMS (stock) to 60 watts RMS to match the new speaker, I would have reduce the new subwoofer's resistance to 2.666666 ohms, which is one third of 8 ohms. I could do so by wiring a 4 ohm resistor between the terminals of the subwoofer, (putting it in series). So, to recap, my questions are, what is the stock subwoofer's resistance, and, what is the stock amp's power rating? And if the answers to the above are 8 ohms and 20 watts RMS, would soldering a 4 ohm resistor between the positive and negative poles on the subwoofer provide the desired result? Or would there be a small explosion in my interior followed by fire and lots of pain?

Yup, it's a crazy idea - sounds good, but won't do what you're after.

Assuming you did connect a resistor like you describe and the amp was capable of delivering that much current then 20 watts would go to the speaker and 40 watts would be dissipated in the resistor. No gain in audio power would result.

However, the amp isn't capable of sourcing that much current - not for very long, anyway. Smoke would result...

Even if the amp could handle that amount of power draw, the sound quality would be terrible. You'd probably get alot of clipping. And like Whuffo said, the extra power would be eaten up by the resistor (and turned into heat) anyway.

While replacing the original 10 Ohm speaker with an 8 Ohm speaker will probably be OK, anything with a lower impedence may be asking for trouble. If the stock amp plus Rodney's sub don't have enough "oomph" for you, you should start looking into aftermarket components.

Unfortunately, you won't be able to magically get 60watts rms out of the stock amp. If you want more oomph, you could probably find a cheap 4 channel amp that would do exactly what you wanted. A cheap 4x25 amp could power both your front speakers, and you could bridge 2 channels to power your 8ohm sub with about 50rms. I gotta run for now, but if you want more info pm me.

------------------

Actually, I got fed up with the crappy bass and took the stock sub out to see if the previous owner installed Rodney's sub right. I have seen things the guy had done elsewhere and I was suspicious.

Turns out I was correct in my suspicions. First, he routed speaker wirebetween the grate and the housing, allowing pressure to leak and cracking the housing. Also, he tightened the 8 bolts around the outside WAY too much and cracked the housing at every screw. Some cracks were 1/4" wide (I think pressure can get through that? /sarcasm)

He also installed the sub like a fricking retard. He must have thrown away the instructions, because he dremeled off some of the metal ring on the speaker to get it fit in the plastic grate with the bracket on top, like the stock speaker. The gasket was squished to about 2 mm thick. The trump card was the wiring. He took a short lenth of speaker wire and attached it to the stock wiring with twist caps. Then he stripped 1/2" off the other ends, and put the wire through the hole in the connection tabs, and bent it over to hold it in place. The wire was corroded really badly, I cannot believe the thing still worked.

I have installed a new sub from Rodney correctly, and plan on running the wire out of the port when I get the new housing from the Fiero store. I will SOLDER it to the tabs, and SOLDER/HEAT SHRINK WRAP it to the stock wires. I swear, I think this guy had a learning disability.

[This message has been edited by Bigfieroman (edited 04-04-2005).]

And then you have to worry about IMPEDANCE MISMATCHING...

Basically the maximum power through two resistors is when they're both equal.....

In other words, the stock amp will only work at full capacity when it's connected to the right load, whether it's 8 ohms, 10ohms, 4 ohms, whatever.