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Six Four
03-14-2005, 09:01 PM
Would a 1983 Mercury Blk max 150 have a big enuff charging system to hold up a battery runing a 500 watt amp and a set of 8 in subs????

pyro
03-14-2005, 09:53 PM
Not running the amp at high levels for a long time! Think about it:
16 amp charge system: 16 X 12 = 192 watts
40 amp charge system: 40 X 12 = 480 watts
...And this is just how much the motor can SUPPLY! And then you factor in the ignition system and other misc electronics...
(When the engine is running, the system may actually be supplying between 12 and 14 volts)
The amp will easily consume more power from the 12v system than its rated output power, because of inefficiency, much of the energy is wasted as heat. A 500 watt amp can routinely DRAW over 600 watts from the 12 volt system with the stereo only cranked up 2/3 of the way! This may be OK for 10 minutes of loud cranking audio, but will drain you down quickly. The amp will only draw a small amount of power at most reasonable volume levels, maybe less than 50 watts, so use it reasonably, and you'll be OK.

-chad

Six Four
03-14-2005, 10:15 PM
Not running the amp at high levels for a long time! Think about it:
16 amp charge system: 16 X 12 = 192 watts
40 amp charge system: 40 X 12 = 480 watts
...And this is just how much the motor can SUPPLY! And then you factor in the ignition system and other misc electronics...
(When the engine is running, the system may actually be supplying between 12 and 14 volts)
The amp will easily consume more power from the 12v system than its rated output power, because of inefficiency, much of the energy is wasted as heat. A 500 watt amp can routinely DRAW over 600 watts from the 12 volt system with the stereo only cranked up 2/3 of the way! This may be OK for 10 minutes of loud cranking audio, but will drain you down quickly. The amp will only draw a small amount of power at most reasonable volume levels, maybe less than 50 watts, so use it reasonably, and you'll be OK.

-chad

thanks, I'll just stick to my radio and some 6x9's

pyro
03-15-2005, 11:20 AM
There's nothing wrong with adding a sub or two, just don't crank the hell out of it for more than a few minutes at a time. At most listening volumes, the amp will not add a lot of current draw.

KaptainKirk
03-15-2005, 11:29 AM
Farad Caps in the equation?????????

WATERWINGS
03-15-2005, 12:29 PM
I am running two amps, (1020 watts) and all I do is charge the batt every time I come in, but if I play it real loud for more than two CD's , (wide open), it will be slow to crank.

150aintenuff
04-02-2005, 12:38 AM
the sure fire way to ensure a strong battery at the end of the day of rocking is 2 batterys, big capacity ones at that... ( interstate, optima, ect.. (not cheepo crap) a efficient set of speakers and a very efficvient amplifier.. I have a 700 W ( rated) Sony Xplode powering a 12" kicker dual coil sub and 2 6.5" and 2 6x9" ran off of deck power for mids and highs( rated 48W a channel) ( reality is 300W for sub and 24W perchanel highs) and ca listen to it all day at resonable volume ( still talk over it) and be fine... can run about 3 hrs before the deck shuts off due to low voltage at 11.5 V under full tilt volume.. had capasitors on prior sterio and draw is still there but the spikes that can trip fuses and peek out the draw capibility on a battery is elliminated... it did however clean up some EMI and other noises I had comming through the power lines.

sho305
04-05-2005, 10:26 AM
I wouldn't worry about it if you have a good battery. I would try for 10" if you can fit them, they will give more thunder for the same power and move more air. You can do what I do, and take a jumper pack and run the battery out (well close). Then jump it and go home. That way you know how long you can go. In fact for <$40 and light weight, why not have a jumper with you all the time if you are going to be cranking the tunes? They even have a voltage meter too.

You can use lighter subs maybe, a bigger ported box, that might help it be more efficient but will limit power handling. However a smaller amp can be as bad because it will distort that type of setup and trash it faster.

Another option is to go with a 4ch amp and 4-6x9s, its not that bad if you get the right 6x9s that have some bass. Some high power speakers don't get the bass you know, that can make a big difference at medium system power levels say 100-500max total. Lastly you can always get a big booster.

Yeah a lot of stuff is figured on 14.5 volts, as that is what a car running will have. Obviously there is a difference to 12 volts, maybe under that when the battery goes down. So for the same volume your wattage use would go up as the voltage went down, providing the amps can do it. 300watts/14.5=20.7 amps....300watts/12v=25amps. Of course, how many times have you blown a 20 amp fuse on your 300watt amp?;) Lotsa bs there. Most of the cars I had the sub amp would start cutting out at high volume and then I knew it was time to start it up. No capacitors on that.

pyro
04-05-2005, 11:14 AM
If your 300W amp has a 20 amp fuse, it's not a 300W amp. Sometimes they say "300 Watts Max Power" on the front of a 100W amp, that's where the BS usually is. "Max" ratings are an invented number that doesn't apply to any real-world factors.

I have a 4 channel 320 watt amp in my car for the main speakers, 80W X 4, and it has a pair of 25 amp fuses, one for each stereo pair.

As I previously stated, amps are not anywhere near 100% efficient. Much of the energy they draw is wasted as heat. A 300W amp OUTPUTS 300 watts to the speakers, but it will actually DRAW 400-500 watt peaks of power from then system.
The fuses' rating, multiplied by 12 (for watts), will usually be around double the amp's rated output power. The amp will only draw this large amount of power if its circuitry fails or malfunctions, thus blowing the fuse and protecting other circuitry from further damage. This is not a benchmark for comparison since each amp is differently designed and built, but typically the fuse rating (or total sum if there's two) will be around double the amp's rated output.

When you want to talk about amp output, the only wattage rating that matters is the WATTS RMS rating, and even this rating is not standard, since many amps are rated with 13.8 Volt supply, rather than 12 volts.
"Max", "peak", or "music" power are nonsense bull-schmidt ratings, and they are usually only printed on the tops of cheap, crappy amps.

Like Sho said, a quartet of properly mounted 6 X 9's can output a lot of low-end without needing a sub, except when huge amounts of volume is desired. If this is the case, the 6 X 9's should be powered by a separate 4-channel amp with a high-pass crossover feature to remove the lowest bass tones from the 6x9's to avoid distortion. The subwoofer and its separate amp will produce those tones instead.

Sealed, non-ported subwoofers typically have the most accurate sound reproduction. No boomy "peaks" at certain frequencies, no "muddy" tones, etc. They are NOT always the most efficient at turning WATTS into sound VOLUME, but they usually sound the best. A good quality 10" dual-voice coil sub in a sealed box, powered by a good quality 100x100 or 150x150 watt amp (with the low-pass crossover feature to remove highs), will provide plenty of low end for most marine systems without draining your battery or weighing you down too much. I'm personally a big fan of the Infinity Perfect sub, because of its high efficiency and good power handling.

The "Bazooka" 150W powered subs are also very efficient and cost-effective for moderate bass. They are nice and small, good sound for moderate volume levels.

-Chad

sho305
04-06-2005, 11:41 AM
Good points pyro. I have two older amps for example; a blaupunkt 120 and a 300 pyramid. I used both on various sub setups mostly 2 or 4 10"s with an electronic x-over. The pyramid was looser and worked better with a tighter sub box, but overall they were about identical in volume performance. I liked the blaupunkt a little better though, as I like looser boxes that really get down to the bottom. It had more dampening on the subs for sure. I mostly used larger ported boxes, could really shake the car for this low buck setup. To be honest, I didn't want it to go any louder. Usually I ran the same or slightly smaller clean amp for the mid highs with this subs setup. It was a very good sounding system that would blow the 30 amp fuse on the battery for the two amps, once in a while. I made larger and lesser systems, but it sure was hard to make the larger systems work as well. The quality of your crossovers was the number one thing that killed sound also.

Yeah I like big ported boxes but you can't run them with huge power. At that level though, you will get a lot more out of your mid-sized amp with ports. It depends on the app of course, but half the time I could tune the subs that way even. Just loosen the box until they are moving good, and that is the most you will get out of a cheap standard sub at that power. If that aint enough, you need twice the amp and better sealed box subs, or a sub with a correctly tuned box it is rated for. On the other hand, the sealed boxes are smaller...and do have better sound. I just wanted thump though.

You find certain things that work well, so you use them! Phillips tweeters were the best years ago...pyle subs were very durable if not the best sound. But now there are just tons of types and brands, still many are not that good. It sucks because nobody can go and test all the stuff to find out what they needed. Back when I was really into it Kenwood speakers were popular, but very bright. So, if you needed bright in your app they were great, if not they sounded like a tin can buzzing in your ear. Anyway, if I were going low buck/lower power the subs would be the last thing I would be spending on. I would try to go 10" rather than 8", or a single 10/12" that will handle more power can also work. Of course if you distort them and really beat them, then you better spend more.

BTW, if anyone has used unpowered sub tubes please post. Preferably 10-12" subs. Interested in what you think about the sound from them in that light package.