Need sound system advice

[bluewater19]

Re: Need sound system advice

Micheal,<br />I have a 1000 watt rms digital 1 channel sub amp made by mephis audio works powering 2 JL audio 10" subs(2 ohm) in a 4th order bandpass box inside my cabin with a 1000 watt peak power 4 channel zapco amp running four MB Quart 6x9's (2ohm load) and four MB Quart 6 1/2's(also 2 ohm) and one 750 peak watt old school fosgate 2 channel amp running 2 MTX truck boxes that I can move around when beached. They are all controlled through a JVC head unit.<br />The 6 1/2's are mounted in the cabin and the 6x9's are mounted in the cockpit area.<br />All three amps are mounted inside the cabin.<br />The Head unit is also in the cabin with a remote in the cockpit. <br />I have 2 interstate deep cycle marine batteries in parallel mounted to an Isolator for the stereo system.<br />The boat suff is all on the Starting battery like stock. <br />My boat has a 55 amp alternator and It ususally keeps up fine with keeping the batteries charged. I play my music pretty soft now.<br />I like being able to hear it when cruising though!!<br />I use a cheapo 2/10/50 amp charger to keep my batteries topped off at home. <br />This system has worked fine since 2001.

 

[18rabbit]

Re: Need sound system advice

Micheal - shoot me an email at BrainDeadBunny@yahoo.com

 

[waterone1@aol.com]

Re: Need sound system advice

Bluewater, you said that you had a four channel Zapco amp running four quart 6X9's (two ohm load).....are those 2 ohm speakers ? It seams that you toss around the 2 ohm load spec like it is a desirable thing ?? While it is true that under ideal conditions a power amp will (if designed for it) put out more power at 2 ohms than 4, the dampening factor(the ability of the amp to control the back EMF of the speaker motor assembly) goes way down at 2 ohms as opposed to 4 ohms. Also the stress on the output transisors (or mosfets) and the stress and likely sag of the power supply, in my opinion creates more of a liability than an asset when running a system at 2 ohms.

 

[bluewater19]

Re: Need sound system advice

Waterone,<br />Mosfet<br />Metal oxide semiconductor field effect transistor.<br /><br />The zapco amp is 2 ohm stable.<br />The memphis is 1 ohm stable<br />Fosgate 2 ohm stable also.<br /><br />If you reread above I state four 6x9's and four 6 1/2's on the Zapco amp.<br />How else would you wire it as to have 4 speakers in cockpit and 4 is cabin with one 4 channel amp???<br />Two 4 ohm speakers per channel parallel =2 ohm load per channel.<br />If I wire series instead of parallel thats an 8 ohm load per channel.<br /><br />These amps are highend units designed to power multiple speakers with 2 ohm total resistance.<br />I have never had a problem with any of my amps overheating. I also have a 1 farad cap wired to each amp to prevent power loss under high load.<br /><br />I am curious as to how would you wire this system without adding more amps or losing any speakers??<br /><br />You seem very up on this subject. Do you work with electronics for a living???<br /><br />I am an electronic tech for the dept of navy and work on high power(50KW+) VLF LF and HF radio transmitters every day.<br />While I don't wire stereo systems every day I do grasp the basics.<br /><br />Thanks

 

[18rabbit]

Re: Need sound system advice

I have an AM/FM clock radio w/9v battery backup. Don’t know how many watts it puts out but there is a 4-in speaker mounted in the cabinet.<br /><br />Edit: make that a 3-in speaker.

 

[swist]

Re: Need sound system advice

Don't do it. It's a safety as well as noise-pollution issue. It will keep you from hearing horns and other signals, and will make it difficult to monitor your VHF. Keep the ghetto blasters in cars.

 

[waterone1@aol.com]

Re: Need sound system advice

Blue water, sorry I misread your post that you had 8 speakers on that 4 chanel amp. By the way yes, I do work in electronics, have done so for about 25 years. You are correct, I would add an amp. While pushing everything to it's absolute limit works for some folks, I always take the more conservative approach, I never run anything below 4 ohms unless it is an emergency situation.

 

[michealprater]

Re: Need sound system advice

A few years ago I could understand the arguement of not running your amps at a 2 ohm load. But with the way amps are built now days, 2 ohm stable, that is exactly what they are STABLE at 2 ohms. In fact most subwoofer manufacturers now offer 2 ohm subs. Why you ask? Because todays amps have no problem pushing them, and the amp still stays cool because it was designed to do so. In competitons, several people are now dropping their ohm loads to 1, to get the most possible power out of smaller amp ratings. If you equipment is older, avoid 2 ohm loads or lower. However, if you are buying new equipment, there is no arguement, drop it to a 2 ohm load. It will not hurt a thing.

 

[waterone1@aol.com]

Re: Need sound system advice

If maximum sound level is your most important objective sure, run it as low as the amp will take. They have been making professional power amps for several years that are stable down to two ohms, yet most of the professionals do not design permanent installs to run at 2 ohms nor do they run their "portable" systems at 2, they know better.

 

[michealprater]

Re: Need sound system advice

I do not want to argue this, but what is the point of manufacturers making 2 ohm subs?

 

[chuckz]

Re: Need sound system advice

Actually, Techron has made amplifiers that will drive loads less than one ohm. These amplifiers will work in the voltage mode or current mode. They were routinely used in the low ohm, current mode to drive ESS vibration systems.<br /><br />Why 2 ohm speakers? In an amplifier system powered from a car or boat electrical system the maximum supply voltage is nominally 12 volts and cannot be changed. The speaker's impedance determines the maximum current. Power equal voltage times current. In order to increase the power output you can't increase the source voltage. Therefore, you have to decrease the speaker impedance, resulting in increased current and power.<br /><br />In an amplifier designed to handle the current, driving two ohms loads is no problem.

 

[ebsworj]

Re: Need sound system advice

I think it would be very interesting to see everyones ages that are associated with this thread. It seems there is a huge age gap that may be accounting for posts telling people what THEY think someone shouldn't do with their stereo v.s. contributing any info. I mean this is the "NEED SOUND SYSTEM ADVICE THREAD". <br /><br />I'll start I'm 26 and think a large stereo is whats needed on large lake to hear the music at WOT. I have no interest in forcing my music on others and stay away from fishmen based on common sense. If I'm in the middle of a HUGE lake blasting music don't come fish by me.<br /><br />Thanks for all the good information so far!

 

[michealprater]

Re: Need sound system advice

I am 27 I was the one who needed advice. My question was more about how to power the system on a boat than about what ohm load to drop it my speakers to. I have been doing car stereo installs since I was 16, but since cars alternators are so much better and stronger that boats, I needed advice on getting more juice.

 

[captharv]

Re: Need sound system advice

My advice for charging the batteries is to get a shore power, "smart" or 3 stage automatic charger. Plug it in when at the marina or on the trailer in your yard.<br />All those amps should drain about 25 amps per hour<br />(class A audio) <br />So, 2 hrs is 50 Amp Hours (AH)<br />Alternator charging is done with a regulated voltage, and tapers off in current as the battery charges up.<br />IF the motor has a 35 A alternator, then,with the stereo and amps running, there is nothing left for charging the battery. <br />Even with a 50 amp alternator, it would take many, many hours to recharge the batteries.<br />Is that what you wanted to know?<br />Captharv