m100 power ratings

Need help with your car stereo system? Have a technical question? Post here.
Post Reply
User avatar
Havoc
Posts: 12
Joined: Fri Nov 09, 2007 8:59 am
Contact:

m100 power ratings

Post by Havoc »

Hey guys,

Quick question here, I been getting alot of different numbers about the output wattage of my m100. My manual states @ 13.8v it will output 250x2 2ohm stereo, 455x1 4ohm bridge. PG's webfaq states @ 14.4v it will output 230x2 2ohm stereo, 500x1 4ohm bridge. Ampguts has it rated @ 13.8v as 230x2 2ohm stereo, 455x1 4ohm bridge and @ 14.4v as 250x2 2ohm stereo, 500x1 4ohm bridge.

I am running 2 JL 12w3v2 D4's and can run either 2ohm stereo or 4ohm bridge. The 2ohm stereo config seems to put out more power to the subs and less hot than trying the 4ohm bridge. Which configuration actually produces more power or are they the same? An email from a rep at PG stated that the 4ohm bridge would produce about 20 more watts per channel than the 2ohm stereo config, however that seems far from my actual results. Feel free to toss any ideas and or comments my way :lol:
Thanks
Power is not given....
...it is taken
User avatar
Eric D
Short Bus Driver
Posts: 4259
Joined: Sat Dec 30, 2006 8:50 am

Post by Eric D »

It should be the same. If it is not, I think your amp is defying physics.
User avatar
Havoc
Posts: 12
Joined: Fri Nov 09, 2007 8:59 am
Contact:

Post by Havoc »

Thanks for getting back to me on the subject. Is there a way to check output with a DMM while using the different loads? And yes i'm sure my amp is limited to the laws of physics like other amps :wink: . I'm just trying to get some advice and or information from people that have real world experience. Since the m100 manual lists lower power output at 4ohm bridge than 2ohm stereo, I have become a bit confused as to which is really the better setup for higher output. Thanks again for you help.
Power is not given....
...it is taken
User avatar
Eric D
Short Bus Driver
Posts: 4259
Joined: Sat Dec 30, 2006 8:50 am

Post by Eric D »

Since electrically your amp will produce the same power at 4 ohms mono as it will at 2 ohms stereo, this is a matter of personal taste, not power levels.

If you have some music with stereo bass, you will benefit from stereo subs. You also need a divider in your enclosure for stereo wiring, as each sub would require its own volume when wired this way. If you don’t have a divider, you are forced to bridge the amp at 4 ohms.

Very little bass is stereo, so there are only specific tracks you will notice this on.

Also, when you are talking 400W or so of power, a difference of 50W would not even be noticeable to the human ear. So, there is no gain in picking the higher powered choice, even if your amp actually made more power wired differently.
User avatar
Bfowler
Briaans..... BRIAAAAANNNNNNS
Posts: 10769
Joined: Wed Dec 06, 2006 11:06 am
Location: So easy, a cavewomen could do him

Post by Bfowler »

An email from a rep at PG stated that the 4ohm bridge would produce about 20 more watts per channel than the 2ohm stereo config
which rep said that? that just dont make no sense
my ex-girlfriend said "its car audio or me"
i've had tougher choices at a soda machine...
User avatar
soth
Posts: 368
Joined: Tue Jan 16, 2007 10:48 am
Location: Southeast Kentucky

Post by soth »

Bfowler wrote:
An email from a rep at PG stated that the 4ohm bridge would produce about 20 more watts per channel than the 2ohm stereo config
which rep said that? that just dont make no sense
Phil
Head Unit: Eclipse CD5000
Amp1: Ti 500.4
Amp2: MPS2500
Crossover: Audiocontrol 6xs
High/Mids: ID CD1-E v1 Horns
Midbass: IDQ 6.5 v2
Subs: IDQ 12 v1
EQ: PG EQ215-X
User avatar
Havoc
Posts: 12
Joined: Fri Nov 09, 2007 8:59 am
Contact:

Post by Havoc »

Soth is correct, the rep was Phil. Thanks again guys for responding to my post.
Power is not given....
...it is taken
User avatar
Bfowler
Briaans..... BRIAAAAANNNNNNS
Posts: 10769
Joined: Wed Dec 06, 2006 11:06 am
Location: So easy, a cavewomen could do him

Post by Bfowler »

I'm not question Phil's expertise...that just makes no sense to me.

crazy.
my ex-girlfriend said "its car audio or me"
i've had tougher choices at a soda machine...
User avatar
soth
Posts: 368
Joined: Tue Jan 16, 2007 10:48 am
Location: Southeast Kentucky

Post by soth »

Bfowler wrote:I'm not question Phil's expertise...that just makes no sense to me.

crazy.
*nod* :)

If you can hear/see a difference between the 2 ohm stereo v/s 4 ohm bridged then something is probably wrong for sure. From the sounds of it Havoc can really tell a difference between the two. If it was a few watts you couldn't tell a difference at all. From the sounds of it the bridge function just isn't putting out the power it should.

If that is the case is there anything that would be the obvious as to why the bridge is not putting out the power it should?

Could the switch be bad or whatever it is that switches between the stereo and bridge mode?

Just some ideas :) :)
Head Unit: Eclipse CD5000
Amp1: Ti 500.4
Amp2: MPS2500
Crossover: Audiocontrol 6xs
High/Mids: ID CD1-E v1 Horns
Midbass: IDQ 6.5 v2
Subs: IDQ 12 v1
EQ: PG EQ215-X
User avatar
Eric D
Short Bus Driver
Posts: 4259
Joined: Sat Dec 30, 2006 8:50 am

Post by Eric D »

I can think of only one reason why bridging would not be as loud as stereo. The phase is wrong somewhere.

For example, if you send a right channel signal into an amp, and a left channel into an amp, except the left channel is 180 degrees out of phase, the amp will “bridge” this signal, and the sum will be zero. You will have no output from the amp.

So, if one channel were 90 degrees out of phase with the other, it would only add half of the voltage and you would get about 56% of the power you are supposed to be getting.

No amplifier is perfectly in correct phase between the channels. This would imply that stereo use is better, as it would give you more power, but this is not really true either. If the amplifier is not in perfect phase, and you run it stereo for more power, your woofers will be out of phase by this same amount, and they will acoustically sum to the same thing, gaining you nothing.
User avatar
Eric D
Short Bus Driver
Posts: 4259
Joined: Sat Dec 30, 2006 8:50 am

Post by Eric D »

If a device further up the signal chain is using time alignment right to left, and is applying it to the same signals which feed the woofer amplifier, this would account for the loss of phase, and lower bridged power output.
Post Reply