Stereo and AMP Power question????

[natedog337]

I'm purchasing 4 new speakers for my pontoon boat. They are infinity 4 ohm speakers with 225 watt max. I'm looking to power them with a marine amp (60W RMS x 4 channels at 4 ohms and ?1% THD + N). Wondering is this amp will be under powering the new speakers. My current head unit is a jensen 4x40 watts stereo. I don't know much about stereos but im assuming my stereo is powering my current four 4 ohm speakers at 40watts per speaker. Will the marine amp only give me 20 watts more power since it is a 60w rms. Wondering if i'd even notice the difference if that was the case. Again sorry but im ignorant with stereos and amps. Thanks for the info......................

 

[Silvertip]

Re: Stereo and AMP Power question????

You may be confusing speaker wattage (the amount of power the speakers can handle) with the amp/stereo power output wattage. And then there are all sorts of power ratings (Peak, Peak-to-Peak, RMS, etc) so you need to compare the numbers and make sure you are comparing apples to apples. 225 watt speakers means they can "handle" that amount of power from the amp or stereo. It is not as thought the speakers are "demanding" that amount of power. I guess I question the need for the amp in the first place since 40 watts should be enough power to drive you off the pontoon and raise the ilk of other boaters and home owners on this body of water -- unless of course you are on a very large body of water. And since you are adding an amp, does the pontoon have another battery specifically for accessories. And does the engine have an alternator with enough output to keep TWO batteries charged. Most outboards do not have very high output alternators so you would need to run wide open for hours to come even close to fully charging a deeply discharged battery(ies). There is no free lunch here. More power means more battery power is needed. Batteries need to be recharged quickly so an on-board charger is likely needed so you can plug in at the dock to top off the batteries.

 

[KD4UPL]

Re: Stereo and AMP Power question????

I strongly suspect your current Jensen is not rated at 4 x 40 watts RMS. It is probably a peak rating with a fairly high level of distortion. You will need to consult the manual to find out the RMS rating of it's built in amp. I would bet it's around 17 to 20 watts RMS.
4 x 60 watts RMS in a boat should be plenty of power. In any case, most any amplifier will provide better sound than the built in amp in most any stereo so I would definitely install the amplifier.
As Silvertip noted, feeding it sufficient voltage and current to operate is an other matter.
I'm going to assume your pontoon has an outboard, most of which don't generate a lot of excess charging amperage. I'd look into that first.

 

[swire]

Re: Stereo and AMP Power question????

Your current radio is 4x40 which is the peak power. It is only pushing about 13 watts RMS. The new amp is 60 watts RMS which could be anywhere from 180 to 250 watts peak. Then manual should tell you the peak power. Any way you look at it the new amp will be providing 4 to 5 times the power that your radio is.

 

[sevillity]

Re: Stereo and AMP Power question????

I agree with all the above. I can atest from experience that you will notice a SIGNIFICANT improvement in clarity, power, and overall sound quality having your speakers powered by an amp. Just be sure your 225watt speakers are rated for at least 60watts RMS or more(they likley are). If you don't already, you may want to add an extra onboard battery to supply power to the amp connected with a batery switch. It won't take long to drain a battery running using this more powerful stereo. It would be aweful if your tunes left you stranded!

 

[ve3rpm]

Re: Stereo and AMP Power question????

Into the fray... If a speaker is rated at 225 Watts, assuming it's RMS, then it means that 225 Watts RMS are required to attain full throw. Less power and you run the risk of clipping. RMS is calculated as Peak X .707 = RMS (root mean square)

 

[Ciera2450]

Re: Stereo and AMP Power question????

the first post stated infinity speakers with 225 max. they are likely about 100watts rms. The amplifier providing 60w rms....

The speakers and amp will sound great.

 

[bouttime007]

Re: Stereo and AMP Power question????

I'm purchasing 4 new speakers for my pontoon boat. They are infinity 4 ohm speakers with 225 watt max. I'm looking to power them with a marine amp (60W RMS x 4 channels at 4 ohms and ?1% THD + N). Wondering is this amp will be under powering the new speakers. My current head unit is a jensen 4x40 watts stereo. I don't know much about stereos but im assuming my stereo is powering my current four 4 ohm speakers at 40watts per speaker. Will the marine amp only give me 20 watts more power since it is a 60w rms. Wondering if i'd even notice the difference if that was the case. Again sorry but im ignorant with stereos and amps. Thanks for the info......................

Remember, RMS is simply the normal operating level over a period of time. Peak wattage is only going to be measured in seconds, and is usually a bogus # anyway. RMS is mainly what you want to consider when setting up a system.

That amp probably wont be underpowering the speakers, but its not all that much RMS either. It should suffice till you decide its not loud enough.

That Jensen is not pushing much more than 17 watts per channel RMS, which should suffice till you decide its not loud enough.

I think you will be ok with what youve got right now. Set it up and see if trips your trigger, if it doesnt, chuck the Jensen and get a Clarion. LOL

 

[ve3rpm]

Re: Stereo and AMP Power question????

225X.707=159
Sure they will sound great? If you run 100 Watts less, you will not get the bass that the drivers are built to reproduce. Just letting you know. They are good speakers and don't fudge the numbers. I would tend to believe the data the Manufacturer provided.

 

[ve3rpm]

Re: Stereo and AMP Power question????

RMS is always the operating level. You basically lose 30% of your voltage once you actually require current flow. It's has nothing to do with time.

 

[bouttime007]

Re: Stereo and AMP Power question????

RMS is always the operating level. You basically lose 30% of your voltage once you actually require current flow. It's has nothing to do with time.

Well Im no expert by any means but...

The "operating level" is an equation that incorperates time of the sound wave(s) too.

Complicated signals (music) are irregular waves, and the power is changing continuously, so to figure out "RMS" power in a complex irregular waveform you do what? Is it not a timed sequence?


RMS power rating is a measure of continous power measured in watts and the device is either able to provide or accept the specified power over a significant length of time without fail.

On the other hand, peak power is simply a measure of how much power can be generated or handled for a very short period of time.


Bouttime...LOL

 

[ve3rpm]

Re: Stereo and AMP Power question????

http://myhometheater.homestead.com/rms.html

 

[hrdwrkingacguy]

Re: Stereo and AMP Power question????

A 50 watt amp or a 150 watt amp is better then deck power any day...The engineering of it isn't important...All that matters is decks aren't made for power and an amp is the better way to go...Get something that is close to the wattage of the speakers per channel and it will sound fine...I defy anyone to show me there acoustically perfect sound stage on their boat...

 

[j_martin]

Re: Stereo and AMP Power question????

Don't pay any attention to Ve3rpm.

I don't have time or inclination to debate him. Just ignore him.

 

[bouttime007]

Re: Stereo and AMP Power question????

Don't pay any attention to Ve3rpm.

I don't have time or inclination to debate him. Just ignore him.

Done deal J.

 

[ve3rpm]

Re: Stereo and AMP Power question????

(Don't pay any attention to Ve3rpm.)

Kinda funny. I thought that the forums were here to help one another. If you want to fight physics, that's just fine. It won't work but it's still fine. There are lot's of tutorials on-line concerning audio. Try wikipedia, or a myriad of other sites that can be trusted. It'll pretty much prove me right and the other guy somewhat mistaken. I just keep thinking I would be remiss if I didn't try to do the best I could. I have gotten a lot from these posts, and it seems prudent to try to help others in return. Anyone reading this just has to google about sound and audio to learn the truth. You be the judge... Someone should have gone to school or read a book concerning audio before offering advice. Maybe it sounds good in your boat, but it could sound better, if you weren't so afraid to admit you don't know what you are talking about when it comes to audio...

 

[j_martin]

Re: Stereo and AMP Power question????

Must be true. I read it on the internet.

Never mind 45 years of electrical engineering experience.

 

[ve3rpm]

Re: Stereo and AMP Power question????

More posts, but less actual knowledge. 45 years in the biz would kinda make one think you knew what you were talking about. If you wanted to help, then actually share the truth. Sorry about the bruised ego however if the internet isn't to believed then try the library.
I'm new to boats but not new to audio. It seems sad that you prefer to encourage someone to ignore the facts. How long you have been doing this? Help the guy out and show that your education didn't go to waste. Better yet, toss out some actual numbers to prove what I have said wrong. (good luck).

 

[j_martin]

Re: Stereo and AMP Power question????

225X.707=159
Sure they will sound great? If you run 100 Watts less, you will not get the bass that the drivers are built to reproduce. Just letting you know. They are good speakers and don't fudge the numbers. I would tend to believe the data the Manufacturer provided.

RMS means root mean square. Your simplistic equation implies pure sine waveform, not multiple harmonic audio, however,
Power would be 225 X .707 X .707 for wattage, which would put it at 112 watts RMS.

RMS is always the operating level. You basically lose 30% of your voltage once you actually require current flow. It's has nothing to do with time.

Huh? Do you understand voltage, current, and power (E I = W)

Into the fray... If a speaker is rated at 225 Watts, assuming it's RMS, then it means that 225 Watts RMS are required to attain full throw. Less power and you run the risk of clipping. RMS is calculated as Peak X .707 = RMS (root mean square)

225 max would mean that's the maximum it would take. More would clip, or smoke. Less would only drive it smoothly.

Regurgitating what you've read without understanding is not wisdom, and ad hominem attack is really foolish. If you really want to be an engineer, go to school and pay attention.

 

[natedog337]

Re: Stereo and AMP Power question????

Another question for this thread!! my new speaker/amp setup is complete. Four new infinity 4ohm speakers (225watt max) being powered by a (60watt rms x 4) marine amp. I currently have a dual purpose marine battery (120 reserve) and a jump pack on board. Again, i'm usually sitting on sandbars for about 5 hours with the radio going. The amp manual states that the maximum current draw is 40amps. Now i'm wondering if my setup will be good enough without a second battery or in your opinion i'll end up with a dead battery often.