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Do i have to match wattage between amps in a 5.1 /7.1 HT Setup?

918 Views 3 Replies 3 Participants Last post by  deneb
Equipement list:

Anthem AVM30 THX ULTRA2 Certified,

Anthem MCA30 (225wpc / 180w x3 all channels driven),

Snell LCR 500 THX Ultra Certified Center (150w max amplifier), 90db sens (could be 88db)

Snell B-Minor Fronts (400w max amplifer), 86db sens

Snell SUR 500 THX Ultra Certified Dipole Surrounds (150w max amplifier), 90db sens (could be 88db)

Toshiba HD-DVD XA2 (hdmi 1.3a)

Panasonic PDP50HD8UK with hdmi 1.0 blade

The last purchase to complete my home theater is a two channel amp: The top contendors are:

Anthem MCA20 (225wpc / 190w x2 all channels driven) for my fronts use the MCA30 for center and rears.

Anthem PVA2 (120wpc / 105w x2 all channels driven) for my rears.

Crown or Behringer 200+ watt pro audio amp for my fronts / MCA 30 for my center and rears.

My question is how important is it to have matching wattages between speakers . amps. Already my fronts have 4db Sensativity Difference meaning i will have to turn the other channels down or turn their channel up. Does this mean i should get a higher wattage amplifier, in which case maybe i will have to adjust the levels less.

What happens if i have 200 watt amps for front 3, and 100 watt for rear speakers, does that mean my output will be limited by the lowest amplifier rating? or does that just mean that there will be less headroom and more distortion on my rear channels then my fronts? Can i easily get 75dbs with little to no distortion from a 105 watt amp from speakers with 90db sensativity

I have an SPL meter, so calibration won't be an issue, i just want to make sure i can set it at THX levels (75db) and not be introducing any bottlenecks in my system by having too many or too little watts on my new amps / to my speakers.
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Any wise words of advice?

You are fine, no need to fret at all. You can adjust the respective gains through your processor. All you need is an SPL meter, match the levels with your processor, and you are good to go.

The only bottleneck will be quality of the components and speakers you are using, and of course the room acoustics. Amp WPC will not be an issue
Your total output won't be limited by the channel with the least wattage, it will only mean that particular channel won't have the headroom of other channels and output will be reduced, though even halving the amp power will only reduce output by 3db as long as all the speakers have the same sensitivity rating.

As long as you had equal power across the front, I don't think a lower power amp for your surrounds would be a huge issue, as long as you can still match the levels and not drive the lower power amp into clipping when the front, higher power amps are just cruising along.
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