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View Full Version : Monsoon Amp with Aftermarket 4 ohm 6x9's


Gor
10-18-2004, 08:24 PM
After hearing many horror stories and "oh, don't do that, it'll sound crap!" stories about the Monsoon stereo system and aftermarket speakers, I decided to do some experimenting.

I work for an electronics company as an electronics engineer, so I'm well versed in Ohms, Volts, Amps, etc.

If the Monsoon amplifier was designed to drive 2x 2 ohm loads, then from what I can hear, it does a really good job with 2x 4 ohm loads.

This is what I did:


Pull back seats forward and kneel on them :) ... then remove the four plastic "push-screws" which hold on the rear shelf.
For each speaker, determine which wire pairs are the LOW FREQUENCY and which are the HIGH FREQUENCY outputs from the Monsoon Amplifier.
Disconnect the 6x9 speakers and Un-hook the little plastic clips which hold them to the metal frame.
Carefully lift up the rear shelf in the center and pop one side out. (This gives enough room to remove the speakers and their holders which are clipped together as one unit.)
Remove the actual speakers from their plastic holders and replace them with Pioneer TS-G950M 6x9, 3-way speakers. (I had to clip off one of the little hooks and plasic posts on each holder to get the new speakers to fit.) These speakers are rated at 4 ohms with a sensitivity of 93dB.
Lift up the center of the rear shelf again to pop back in the side which you removed.
Insert the four "push-screws" to hold the rear shelf.
Using a soldering iron (an electronics iron - not a cheapo $10 one from Radioshack or a plumbing iron!) disconnect the thinner insulated wires from the speaker terminals on each 6x9 speaker. These wires lead to the mid-range driver and tweeter on the Pioneer 6x9's. NOTE: do not disconnect the copper braid voice coil wires!
Observing speaker polarity, connect the LOW FREQUENCY amplifier output to the main speaker terminals. Do this for both left and right speakers.
Strip and tin the insulated wires you previously disconnected on both left and right speakers.
Observing speaker polarity, connect the HIGH FREQUENCY amplifier output to the wires you have previously disconnected and stripped.


What this accomplishes:

Disconnecting the mid-range and tweeter connections from the main speaker terminals isolates them from the woofer, hence you connect your LOW FREQUENCY amplifier outputs to these for bass reproduction.

Connecting the HIGH FREQUENCY amplifier outputs to the wires you disconnected, feeds this signal to the mid-range driver and tweeter, reproducing the treble.

Result:

Good sound! Believe me, it works!
Plenty volume, Deep Bass (have my bass control set at 0) and lots of crisp treble.

Of course it's possible that this is just a freak incident and that I got lucky, but I doubt it.

I think this approach will probably work for other 2 and 3 way speakers.

I've attached a pic of the speakers I used to replace the stock ones.

JoeyK
10-18-2004, 08:58 PM
Lol,.. & @ only half the power. Ask the guys @ Monsoon.com when they get the site back up. They'll tell ya the same thing I did. Anyone can divide the woofer & tweeters on a 6x9 but that's not where the true problem lies. The Monsoon amp will give you 1/2 the power & no more w/ a 4 ohm woofer. period/end of story/that's all she wrote.

what's a 2 x 2 ohm load & a 2 x 4 ohm load?

Gor
10-18-2004, 09:17 PM
JoeyK,

Yeah it stands to reason that if you double the load on anything you will only dissipate half the power, but we're not talking purely resistive loads here, we're talking inductive also. The amplifier is driving speakers, and speakers contain coils, which are inductive.

We're also talking about Music... Saying "half the power" in music terms does not necessarily mean "half the loudness". The system sounds great to me, and I'll be glad to give anyone a demo!

"Full power" through a 2 ohm speaker with poor sensitivity might sound the same as "Half the power" through a 4 ohm speaker with better sensitivity.

A "nominal" 4 ohm, 2 ohm, or whatever load means that, at some frequencies, the impedance to the signal may be higher and, at other frequencies, it's lower. As the impedance drops, the amplifier can increase its output but must draw more current to do so. A theoretically perfect amplifier will double its power every time the impedance drops by half, but in reality few are capable of this.

See what I mean? This is a sticky area - there's no black and white to it.

Audio power and quality is all subjective, so there's no argument really. All I intended to do is illustrate how to replace your stock speakers with aftermarket speakers and get a good sound.

BTW, let me clarify:

2x 2 ohms = there were two stock speakers...
2x 4 ohms = there are two new speakers..... ;)

P.S: I won't bother contacting Monsoon, as I've heard that they're secretive about their system ... why? lol....
I'd love to get my hands on the internal schematics for the Monsoon amp so I don't have to reverse-engineer it myself. I'm sure you could bypass the crossovers inside the amp or modify it some way for 4 ohm loads.