PDA

View Full Version : whats the Watt limit?



Strippoker
10-06-2007, 10:06 AM
Ok so most people know we at Ultra hold the record for the loudest stereo in a boat. But here is the question what is the limit when it comes to stereos in a boat. Sure its great to have a big system but when does it go from big to "duta duh"? You know the stereos Im talking about that take 2 small city generators to keep them going for 2 minutes. Guess im curious seeing how a "safe boater" wouldnt be running full throttle with a stereo so load he cant hear other boats. :idea:

Jordy
10-06-2007, 10:07 AM
What?? :D

Strippoker
10-06-2007, 10:09 AM
What?? :D
:D lol huuuuh?

Phat Matt
10-06-2007, 10:11 AM
My stereo is pretty loud but when I am running I turn it off. And by running I don't mean cruising the channel, cuz then it is loud. :D

hkunz
10-06-2007, 10:32 AM
Doesn't this fall into the category of "if it don't go, chrome it"? LOL
Anyway.
Back when I used to pay attention to that kind of engineering, I remember reading that you could work it backwards using mathematics. Take the dB level that you are looking for (I'd go with a max that is just below the pain threshold, say 120, 140, whatever you are willing to put up with), then add for the distance from the emitter to the ear, so 3 dB per foot, in a 6 foot wide boat that's 9 dB, (now we are at 129 dB from the emitter), then divide for the efficiency of the emitter (x dB emitted per watt input). That gives you the power in watts per emitter of clean sine wave. Then you calculate for the type of amplifier (A, B, push-pull, etc.) what the max signal strength is for a pure sine wave (the hardest signal to duplicate, since it encompasses all frequencies). You want the amp output at a pure sine wave level to equal the power at the input of the emitter at a pure sine wave. Repeat for each frequency or frequency range.
You'll have to know the engineering specs for each component or design that you are using (people don't make thier own amplifiers or speakers anymore) to plug in to your calculations. Make sure that when comparing parts that the specs are for the same levels, i.e, peak vs. RMS vs. peak to peak, etc.
This will give you the practical limit for use INSIDE the boat. If you are looking to impress others with a stereo outside the boat, your emitters should point outwards, then do your initial calculations with distance to the prospective listeners/torturees. The Bud Lite pontoon supposedly has 20,000 watts, and we were in pain at 100 feet.
As for powering them, add a second alternator with a dual charging system, and 6 Optima blue-tops to start, then build from there.
Since we don't listen to the stereo when the boat is on (the motor makes the best music:D ) it doesn't have to be that loud.

Strippoker
10-06-2007, 10:45 AM
only 20,000 watts close but not the arc boat.
http://www.arcaudio.com/album/Arc%20Garage/dk_truck_boat_quad/slides/DSCF0076.JPG
over 25,000 of power, multiple generators and power supplies, a onboard computer system (12) 15inch subwoofers and a huge array of components

phebus
10-06-2007, 10:53 AM
I have a slow boat, so I have a loud stereo. :D

Havasu Hangin'
10-06-2007, 11:01 AM
only 20,000 watts close but not the arc boat.
http://www.arcaudio.com/album/Arc%20Garage/dk_truck_boat_quad/slides/DSCF0076.JPG
over 25,000 of power, multiple generators and power supplies, a onboard computer system (12) 15inch subwoofers and a huge array of components
I bet I could build a louder stereo with less than 1,000 watts.
:idea:

Cheap Thrills
10-06-2007, 11:50 AM
I bet I could build a louder stereo with less than 1,000 watts.
:idea:
Ding ! ;) You posted that wile I was working on this..
Why is it that when people talk about sound pressure levels and wanting more, they automatically talk about more power. If your speakers, (Transducers being the proper terminology) are reaching max X with 1kw, 10 kw isn't going to be any louder. If you want more volume move a larger volume of air. Meaning more or better or more & better speakers.
I run a professional grade stage sound system at home and I can guarantee you this 5kw@8ohm stack of Peaveys & QSCs will hold it's own with any 20kw + marine /mobile system out there without breaking a sweat just because it is properly configured with several large cabinets moving extremely large quantities of air. Plus in the mobile industry your advertised power ratings are usually at the lowest acceptable impedance of the amplifier.
Sure that nice (Insert Brand Name Here) is rated 1kw but that's probably at 2 Ohm or less. Raise the impedance to 8 Ohm a real working world level and you're going to be sadly disappointed at the numbers. But that's another subject I shouldn't have gotten into on this thread.
This is not a bash on anyone here. And I'm sure you guys have some incredibly insane sounding systems. I don't doubt some of which are quite painful to listen to at high levels.
I am just stating that a higher wattage output does not necessarily translate into a louder system and is only part of the equation. How much is too much power? Well personally I don't think there is such a thing but if I had to sum it up simply, for a confined airspace such as mobile /marine applications.
Too much power is the inability to use that power you have due to insufficient amount of movable airspace. Or the inability to dissipate the heat generated by the amps and speakers due to insufficient airspace.
Rock On http://www.***boat.com/image_center/data/500/party0030.gif
T.

hkunz
10-06-2007, 12:51 PM
Yup, pretty much what he said:)
I only worked in the electronics portion of the systems, we didn't really get into sound pressure. Before long, some civilian contractor/engineer with a computer figured out how to build a complete turnkey system that allowed for the sound waves to be reproduced in phase over fairly long distances (600-foot long hanger bays, 1,000 foot long flight decks, etc.) so that the announcing system was actually clear and understandable over the whine of jet engines, APUs, forklifts, and fighter pilots, and we turned the whole thing over to the contractors. Much better operation, and now all I know how to do is wire up stuff that someone else engineered, or better yet, watch the contractors do it. Though no longer in that business, it's nice to understand the theory.

Havasu Hangin'
10-06-2007, 01:16 PM
Ding ! ;) You posted that wile I was working on this...
If you want a big number, just let me pick mic placement...lol.
:idea:
"More" is not always better. IMHO, in something as weight-sensitive as a boat, "more" is just for show.
But what the hell do I know?
:messedup:

Cheap Thrills
10-06-2007, 01:35 PM
If you want a big number, just let me pick mic placement...lol.
:messedup:
I literally spit my drink on that. you owe me a beer. :D
Yup, pretty much what he said:)
I only worked in the electronics portion of the systems, we didn't really get into sound pressure. Before long, some civilian contractor/engineer with a computer figured out how to build a complete turnkey system that allowed for the sound waves to be reproduced in phase over fairly long distances (600-foot long hanger bays, 1,000 foot long flight decks, etc.) so that the announcing system was actually clear and understandable over the whine of jet engines, APUs, forklifts, and fighter pilots, and we turned the whole thing over to the contractors. Much better operation, and now all I know how to do is wire up stuff that someone else engineered, or better yet, watch the contractors do it. Though no longer in that business, it's nice to understand the theory.
I believe you're referring to a Phased Focused Horn Array. and is excellent method of covering large areas with intelligible speech. or narrow group of frequencies. The phasing and distancing of the drivers cancel out standing waves which can result in a (for lack of better word) muddying effect of the sound. I have read of some noise cancellation methods using the same type system that cancels out the ambient noise with a computer sampled and controlled reflection of the ambient noise in 180* out of phase.
Anyhoo wayyy off topic now. :D
Take Care.
T.

76ANTHONY
10-06-2007, 02:17 PM
so i guess my sparkomatic stereo and 6x9's arent in the top ten???:D

73kona455
10-06-2007, 02:31 PM
so i guess my sparkomatic stereo and 6x9's arent in the top ten???:D
you could upgrade to a Roadmaster brand..lol:D

76ANTHONY
10-06-2007, 02:32 PM
you could upgrade to a Roadmaster brand..lol:D
i was thinking maybe i'll pull out the old concord cassette deck, wooohooo:D

Strippoker
10-06-2007, 02:39 PM
Man Im rolling old school 8 tracks with house speakers cant touch that.

ROZ
10-06-2007, 03:17 PM
220 , 221 whatever it takes.... :cool:

76ANTHONY
10-06-2007, 03:22 PM
Man Im rolling old school 8 tracks with house speakers cant touch that.
ohhhhh shiat, i guess i best be shuttin the hell up, that shiat is rolloin deep there:eek: :D :D