tower speakers cutting out at loud volumes

I have some tower speakers that are roughly based off of the nvs addictions, so they can take alot of power (400W+ apiece). We I turn the volume all the way up, they cut in and out.

Normally I would think that the amp is clipping at the top of it's output range. However, I originally had my RF Power series amp 350Wx2 and it was doing the same thing. I then hooked up a smaller RF amp 150X2 and it still does it just not as bad.

I then decided to run another large gauge power cable from the second battery in the bow directly to the amp but the problem still continued.

So I am still thinking that it is a power problem not an amp or speaker issue. When I first built the speakers I powered them off of my denon home receiver 150W per channel and had no cutting out. My big RF amp is of the old school variety and is built like a tank.

The boat is a '03 SANTE with the stock alternator and dual batteries. Do you guys think that I need a cap or something else? What about the ground? The original ground wire was run between battery to the ground distribution block. In my old days of car audio I would use the shortest possible ground..usually less than a foot.

Thanks in advance.

Brandon,

Sounds like your amp might be going into protection mode. I had the same problem just recently. I called up Kicker and they told me that the speakers which were supposed to be 4 ohms each were probably like 3 ohms. He said it happens and even they do it. My speakers are MB Quart. I ended up just running the speakers in parallel instead of series. No problems at all now.

I originally thought that too. However, on my old RF Power amp, that thing can handle a 1.5ohm load. I used to run a 10w6 back in the day when they were 3ohm dual voice coils (i think).

The way I originally had them wired is 4ohm per channel. I then tried to run them in series at 8ohms and had the same problem.

do you have enough battery reserve to power them? I was having a similar problem on my boat with my 2 amps and it turns out that it's just that the battery was low. I'm adding a second and got a trickle charger and the problem is solved.

That may very well be a problem. However, I do have two batteries. The amps that I am using is the stock 4-channel kicker amp for the interior speakers and sub, and then the RF 750W amp for the tower speakers.

I would start at the battery Then check all the terminations. I had the same thing happen last year, turned out a 4 gauge crimp was bad.

sounds like a bad connection somewere in your system I would first shorten the runs run everything on the bench (so to speek) pull your amp and your speakers put them on a dedicated power supply and play with it that way. eliminate as many connections as you can like your tower connection. then try pulling and tightning EVERYTHING. youll find it. TR has the right idea bad connections are the route of all evil in the electrical world.
JJ

Does it only happen at the end of the day? Mine will work fine turned up all day then short out towards the end of the day but the sub will still work. The stereo guy said the amps were just overheating.

It seems to get worse as the day goes on. That may be heat or a connection getting looser as the day goes on. The reason I don't think it is overheating is the fact that it will do it cold.

Have your batteries load tested. you should see 12.4-12.5 on a voltmeter (min) with the boat off. any less and your batteries are not fully charged to start the day.

I just rechecked them today....i just replaced teh alternator belt because it broke. I got a good day of riding on the belt, and the batteries are now reading 13.6V with the engine off.

So I think I have narrowed it down to two possible things...

1) Gain not matching/adjusted correctly between the head unit and my amp. Not sure what the preamp output is on the XMD1 but will find out tomorrow with an oscilloscope. Also gotta look up what the spec on the amp is for input level.

2) The original way it is wired is using a very long ground. I have the 12V+ hooked up to the bow battery and the ground is still off of the back battery. This makes for an extremely long path for return power since it is basically making the trip all the way around the boat. I will try to fix this by running a short ground <3' from the bow to the amp.

Rockford amp will shut down if Voltage peaks over 16v or drops to 9v.

So I have eliminated #2 in my list of problems. I reran power and ground cables using 1 Gauge wiring that was only 4' long directly from the front battery. This has seemed to lessen the problem. I have now been able to hook my 700W RF amp and have it at about 3/8 Gain without any clipping. I will have to wait until I get my oscilloscope from work to tweak it. It's kind of hard to adjust it without really pissing off the neighbors.

Anyone think that I might be suffering from insufficient power supply that would be fixed from using a capacitor? Again, thanks for all the help.

If your batteries are charged up and you are running 1 gauge wire i would venture to say that a cap would not help. There are a multitude of variables so an inet forum may not be the best help. Are you sure your batts are 13.6V not 12.6V? One other thing to try is the remote turn on. Do you have the remote turn on straight from the HU? You may want to try a true +12V through a relay (from the battery) for an amp turn on. You may also do this for the +12V for the HU. Can you "test" the speakers again? That would be the quickest way to determine if it is the speakers or the system. Also does the XMD1 have a settingto adjust the output gain? I remember reading about Clarion units that do this however i do not know which unit or units that do this?