Am I looking to make smoke here, or will I be ok?

[psy4s 10+ year member]

I am rebuilding a 1967 Camaro. For the front speakers I have JL Audio C3-650 Component Convertible rated at RMS 75 Max 150 and in the rear I have Rockford Fosgate 8" M282B Rated at 100 RMS 200 Max, and for an amp I have a new HIFONICS ZXi 150.4 4CH AMP that I bought for $230 shipped. I am also running Two Optima Deep charge batteries in the trunk, because the car is Fuel injected, with an electric fan, and two electric fuel pumps, and a 120 Amp alternator. I do not think electricity is a problem, but is this amp going to smoke these speakers? I was told it is ok to go beyond the rated power as long as it is clean power.

I am a long way from having the car ready to put power to anything, I just do not want to start the first drive with a cabin full of smoke. The new Zeus amps are CEA-2006 certified so I think it should put out close to what it is rated.

I could move down to the HIFONICS ZXi 80.4 Zeus Series 4CH AMP it is only rated at 80 per, but I always thought it was better to go over rather than under.

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[vaiboy 10+ year member]

It's normally okay to go a little over RMS but there is still a thermal limit to how much power a voice coil can handle before it burns.

If you are worried you could always limit the amps output when you set your gains.

You will want to set the amps gains using a DMM, basically you are testing the voltage output of your amplifier there are several tutorials for the proper procedure if you search, you will just be making one small change.

To determine your target voltage you will use the formula V = √ (Power x Impedance)

Normally with a 150W/channel amp and 4Ω drivers the formula would look like this.

V= √(150 x 4)

V= √600

V= 24.5

If you wanted to limit the output to 100W you would replace the 150 in the formula.

V= √(100 x 4)

V= √400

V= 20

 

[psy4s 10+ year member]

I respect your opinions or I would not be on this page. I am sure this is a silly question for many of you, But as I try to research anything about Car Audio it gets pretty confusing. I read where one person says he is putting 300w through a set of JL C5 speakers, when they are only rated for 75 RMS/ and 150w Max. Many I see say you Must use Morel, or Focal, others say they love their Kickers. Trust me, Car engine web sites seem a lot easier to follow.

Understanding that as a Vet my hearing is pretty much crap, but I can still hear music. I want a system that is clear, and tight. Can I tell the difference between Focal speakers and JL Audio, I would say NO!, But I can tell the difference between Fishers Home Stereo speakers, my old Bose 901’s and my current Definitive Technologies BP-8080ST towers. In the car there is a whole new consideration. I have a 530 hp 383 Chevy v8 with Pypes Stainless duel Exhaust. Even with the sound proofing, it is never going to be a quiet car. I have to find something that can play my music, (the Eagles, Steve Miller Band, Rush, REO Speedwagon, Nazareth, RUSH, etc.) clear and loud enough to hear over the engine. So groan if you must, but I am serious about my question. If I weren’t, I would not have asked.

 

[Sleeklsc 5,000+ posts]

Just cause someone has a 300 watt amp to a set of speakers doesn't mean the speakers are seeing 300 watts.. The amp is capable of putting out that much power but it's highly unlikly giving it's all the the speakers. You can have a 1000 watt rms amp hooked up to a single 12" 500rms subwoofer and be completly fine if it's setup correctly.

You should be just fine.

 

[Sleeklsc 5,000+ posts]

Also, why are you using marine speakers in the rear? And very expensive one's at that. Just curious.

 

[Jasonc13 10+ year member]

Sweet Camaroeace:

 

[psy4s 10+ year member]

Also, why are you using marine speakers in the rear? And very expensive one's at that. Just curious.

I have been looking for an 8 inch round speaker, and the places top hear speakers are pretty thin around here. I was able to hear a set of these, and they sounded real clear, and real strong. I guess it is a Go with what you know thing. You can get these for $180 which is not too bad. I looked at SST8.2 SOUNDSTREAM speakers for $119 but I have not herd them, and I did not want to buy something I can not hear and no one can tell me anything about.

 

[BnGRacing 10+ year member]

The wattage ratings on speakers are usually more of a marketing tool than anything else. Since there's no industry standard that's enforced, you can't really judge one brand to another on power ratings.

Some say that power ratings are a guideline, I wouldn't even go that far. What I will say is that bass will kill your speakers. Use the crossovers on the amp to filter out low frequencies and you're probably OK. If you want bass, get some infinite baffle "free-air" subwoofers and mount them on a board behind your rear seat. It's an old car, might as well do car audio the old way, right?

 

[vaiboy 10+ year member]

The RMS ratings for speakers are "continuous", meaning the voice coil can dissipate the heat generated by a 75W constant tone. The voice coil can dissipate the heat generated by a stronger signal, but not continuously, the higher the wattage the shorter the duration. Since music is not a continuous tone it is possible for the voice coil to handle the stronger signal without burning up, but if you feed too much power to the speaker even the shorter duration tones in music can do damage.

You wont really know if your system will be loud enough in your car until it is installed and you can listen to it with the engine running. I would suggest starting by setting your gains to the RMS rating of the speakers. If you think it needs more then you can increase the gains, but really there's only a 3dB difference between 75W and 150W.