Overkill

[Shojahan]

Ay yo mayyn,

My new amp has a 90A fuse and rates at 4 X 120 watts RMS. My Pioneer 6.5 front speakers rate at 50 watts RMS.

The reason I got this amp was to bridge the rear channels to my subwoofer. But I'm concerned that even with the gains all the way down on the front channels, it might still draw enough power to blow those Pioneer 6.5 speakers.

My first question is do you think my fears regarding the RMS disparity has any basis? My second question is why does the word "subwoofer" get spell-checked on a Car Audio forum?

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[disturbed471985 5,000+ posts]

yes just set gains with dmm.

 

[imp4pdabest 10+ year member]

I didn't know the word subwoofer gets spell checked.

Best advice to not blow your rear speakers, set your gains with a DMM. A lot of times, RMS numbers are off by a lot. I've owned speakers that were rated only 50rms, but I gave them twice the power daily. Just depends on how good the speakers are. But to be safe, get the amp tuned.

 

[quackhead 10+ year member]

Ay yo mayyn,
My new amp has a 90A fuse and rates at 4 X 120 watts RMS. My Pioneer 6.5 front speakers rate at 50 watts RMS.

The reason I got this amp was to bridge the rear channels to my subwoofer. But I'm concerned that even with the gains all the way down on the front channels, it might still draw enough power to blow those Pioneer 6.5 speakers.

My first question is do you think my fears regarding the RMS disparity has any basis? My second question is why does the word "subwoofer" get spell-checked on a Car Audio forum?

What brand/model is the amp in question?....It either pushes alot more than rated, or very inefficient, guessing by the 90A fusing....2 ohm stable bridged?...I use 60 watt Quarts on 125w/ch rms amp rated at 12.5v. I have had zero problems with them in the last 5 yrs..but I use my ears to determine how hard I push them as well.

 

[trumpet 5,000+ posts]

The amplifier's fuse rating is not the best indication of how much power it can actually make or how much current it will pull. RMS Power ratings on speakers are not an indication of how much power they can handle before blowing. You don't need to match the amplifier and speaker power ratings. Put this all together and there's no reason that amplifier can't be used safely on those speakers, provided you use some common sense and take care with the gain settings and the volume knob.

 

[quackhead 10+ year member]

The amplifier's fuse rating is not the best indication of how much power it can actually make or how much current it will pull. RMS Power ratings on speakers are not an indication of how much power they can handle before blowing. You don't need to match the amplifier and speaker power ratings. Put this all together and there's no reason that amplifier can't be used safely on those speakers, provided you use some common sense and take care with the gain settings and the volume knob.

this is true..I apologize if I misled anyone...but since it was mentioned by op, i figured to comment on it....it's not the best indicator, but it's a good one....that's why I asked the make/model of the amp...I figure such a high fuse requirement may indicate the ability for it to multiply it's output as load decreases....were talking a 480 watt amp with a 90 amp fuse....i'm real curious.

 

[trumpet 5,000+ posts]

Here's something to ponder:

I have a dual fused distribution block for my two amplifiers running my system. The speaker amplifier has 75 amps of fuses yet the power distribution block supplying it has a 20 amp fuse. I have never had to replace that 20a fuse, even after upgrading from a 2 x 120W amp to a 4 x 145W amp. The first amp was A/B and the second amp is Class D.

 

[maylar 10+ year member]

Depending on the sensitivity range of the amp and the preout voltage of your HU, you might be forced to accept not being able to turn the volume control up all the way. Other than that it's fine to have more power then you need.