2004 VIBE M&T amp help!

[Stockintoshockin]

I have a 2004 Vibe M&T with single disc factory HU. I have some tech questions. The front speakers were so so when i got my vibe i replaced them with a Alpine Component speaker in the factory locations. They sound better then stock. The rear speakers on the other hand play about 1/2 to 2/3's of the volume of the front with the fader centered. They also have about as much bass as a gameboy speaker. I have heard the M&T Amp is 200 watts. (1) Is it evenly distributed as 50x50x50x50 and the front speakers are just a better set up? (2) The rear speakers are even right to left no abnormal distortion just quiter is this normal? (3) I have heard the factory amp is for 2 ohm speakers is this true? (my new front speakers are 4 ohm and still plenty loud) (4) I am also looking for a wiring diagram for my factory audio set anyone got one?

[joatmon]

welcome to genvibe (1) no idea(2) never noticed(3) Although I have never verified it myself, that's been the consistent statement here over the years, so I take 2 Ohms as ture(4) http://forums.genvibe.com/zero...o.gif will show the connections to the M&T amp

[Stockintoshockin]

thanks you so much for the diagram i can live with just that answer if no one else knows the others

[audiovibe]

Welcome to Genvibe!!1. The factory system is 200 watts max or yes 50 per channel max, but in real world everyday conditions you have 7-15 watts at most. you will get the 50 watts per channel from the amp once in its life but that will be just before lightning strikes. The reason the GM is advertised it as 200 watts was for marketing. Aftermarket companies such as Alpine use the same tactics, because who wants to buy a radio with 15 watts per channel. The aftermarket companies used to do this religiously to drive headunit sales well past amplifier sales; the reason it worked is because who will spend $400 for a 50x4 amplifier when you can get a CD player that does 50x4 for $200. Since 2006 aftermarket companies are no longer able to just post the inflated output alone, they also have to post the RMS wattage or the true output of the internal amplifier in the headunit. So take the Alpine IVA-W505 for instance, even though it says it is max 50x4 it also says power rating 18x4.2. It has been so long since I have used rear speakers in the vibe but the rear output should have been about the same as the output of the front speakers. Yet the output in the front would be louder from the front because of the tweeter. Because of the position of the tweeter in the sail panel and the general frequencies handled by the tweeter it tends to draw the music more in that direction. At the same time you will hear the mid and mid bass frequencies from the rear as you are closer to that speaker then you are to the front speaker. Kinda like if you have a friend stand 5ft behind you and 10 ft in front of you, both shoot you with a water gun at the same time, you will register the hit behind you first because the water had to travel a shorter distance and got to you first. The reason the tweeters will not follow this rule is because there are no tweeters in the rear to draw back. The frequencies the tweeter produce. the higher the frequency the much more efficient it is to producehere is an example of a scale from 200HZ-475hz.http://www.dosits.org/science/whatis/al ... .mp3notice how the sound changes?3. The factory amplifier can drive a 2ohm load as that is how it was designed. At the same time the amplifier would have no problem driving a 4ohm load. In theory going from a 4ohm load to a 2ohm load will yield twice the power output, meaning that if you want it loud that would make more sense because you would get more power. That is true to an extent the downside is running 2ohm will create more heat and inaudible distortion because there is more current being passed through then the same setup running at a 4ohm load. so even though the factory amp drives a factory 2ohm speaker you would be fine to replace it with a 4 ohm aftermarket speaker (more on this in a min). Going the other direction is where you will run into issues. Using a radio that is rated to drive a 4ohm load and installing 2ohm driver can create some issues. Heat will be one of the biggest issues because of the added current needed to produce the power. When you start using that extra current it will create the heat this will in turn make the radio less efficient at producing power. Now instead of the theory of getting double power from the 2ohm load you are only getting 1.5 times the power and twice the heat. this is what leads to speakers failing due to thermal issues. (That is just an example I really don't think it is possible to make a speaker fail from a radio due to thermal issues).Now back to using a 4ohm driver on an amplifier designed to play at 2ohms. This is such a better option because it is so much more stable. This works just opposite of a 4ohm radio driving a 2ohm speaker. So now your wondering why is it better to have 1/2 the power output? The trade off from efficiency alone is greater, because of less heat and current needed to drive the speaker. The power being produced from the amplifier is a byproduct of the current and heat so it is not really a factor because it is easily over come. This is where the sensitivity of the speaker will come into play. lets say the factory 2ohm speaker had a sensitivity of 87DB, you would have to replace it with a 4ohm driver with 90db to achieve the same loudness. For every 3DB gain you have the equivalent of doubled power, meaning that if an amplifier output 50 watts at 2ohm and your 2ohm speaker was rated at 87db you would need a 4ohm speaker rated at 90db to yield the same results at 25 watts from the same amplifier. You would still reep the benefits of the 2ohm load without the issue of heat and current possibly causing damage to your speakers. This is why the alpines are still pretty loud they are just more efficient then the factory drivers.Hope I gave some clarification to the matter, probably a little deeper then you wanted but hey knowledge is power right?Aron

[Stockintoshockin]

well I can tell you from experience now. (1) The amp isn't evenly distributed power The front door receives more then the front tweeter and more then the rear speakers do. Also it is a 6 channel amp not 4. (2) In my case the rear speakers were quieter because, I believe they had aged or worn and lessor amp output. (3) yes the amp is for 2 ohm and yes it drives my front 4 ohm speakers just fine as well as my 2ohm rears. In the end my new rear speakers still lacks bass. Over all they sounded good in the mid to high frequency. Well some bass wasn't good enough for the 300 bucks that is bolted on to my back seats so....New HU installed and I removed the amp and used the wiring diagram above to cut and soder the wires in to by pass it. In the end I have a more balanced, clearer and richer sound. (note: If you are by passing the AMP be where there is more wires then shown on the diagram!!! and a few are the same colors matching pairs, so I used guess and check method which worked fine)

[AdmRose]

So audio, if I'm reading your post right:4 ohm head unit driving a2 ohm amplifier using speakers rated for 2 ohms is more efficient then 4's all around?

[audiovibe]

If you are using the factory amp then the minimum load the radio can take would not be a factor. The reason this would be is the radio would just be sending a signal to the factory amp, I don't believe there would be any impedance rise or drop as there would be when a speaker is hooked directly to a radio. Yes a 2ohm stable amplifier (such as the factory M&T amp) could be more efficient running at a 4ohm or 8ohm load. This would be determined by the speakers one chose to replace the factory speakers. Lets say that the factory 2 ohm speakers have a sensitivity of 87db, for a 4ohm driver to achieve the same loudness you would need a sensitivity of 90db, an 8ohm driver would need a sensitivity of 93db. Theoretically going from a 2ohm load to a 4ohm load will cut power by 50%meaning the speaker will need to be more efficient at making music to obtain the same loudness. Once again in theory every 3db gained is equivalent to doubling the power. The part where you will gain efficiency would be when running a 4 or 8ohm driver the amp will have to work less. When this happens you achieve 2 things, less heat and less distortion while keeping the same level of loudness.