What would be the effect?

[Jeff T]

If the size of the power wire from a dist block to an amp was too small, even slightly, what would be the ultimate effect? Amp overheat and shut off? What is the impact to sound quality?

Here is why I ask this question. I'm trying to pinpoint the driver of an ongoing issue that I have. At high, but reasonable volume, my tower speakers will dim after a few minutes. They will still produce sound, but they sound muffled. I'm checking a number of things, including battery supply, gain settings, loose connections, etc. I was thinking today about my actual power cables. I'm running a 0 gauge from the batt to the block (roughly 18-20ft) and 8 gauge from the block to amp(s). The run from the block to the amp powering the tower speakers (wetsounds pro 80s) is about 1.5ft. The amp is the kicker 650.4 bridged.

If my power cable from the block to the 650.4 was slightly too small, would it cause this problem? I don't have this issue with any of the other speakers/amps (kicker 350.4 and 750.1).

[lee]

We had a customer with that probem and Wetsounds told him it could be the crossover inside the speaker. He would need to send the speaker back for them to check out and repair or replace.

[mtnsmith]

Holy Cow, two sentences Lee!!!


Are you running seperate grounds back to a single battery? I had a bad crimped ground terminal that bolted to the battery on the lead to my tower speaker amp and was causing a similar issue. Just something else to check I guess.

[Jeff T]

We had a customer with that probem and Wetsounds told him it could be the crossover inside the speaker. He would need to send the speaker back for them to check out and repair or replace.

I sincerely hope this isn't the case. I'm not sure what I'm going to do if it is.

[Jeff T]

Holy Cow, two sentences Lee!!!


Are you running seperate grounds back to a single battery? I had a bad crimped ground terminal that bolted to the battery on the lead to my tower speaker amp and was causing a similar issue. Just something else to check I guess.

For both power and ground, I have 8 gauge from amp to dist block and 0 gauge from dist block to batt.

[dogbert]

On many of the better amplifiers, the amplifier will clip if it's not getting enough voltage or too much voltage. My bigger worry on a cable that's too small would be the heat build-up. Do you have a fuse at the distribution block or is it just connected there?

That said, if your ground isn't big enough, it could cause the voltage to drop to nothing...I've seen that happen before. You can verify that by creating the issue and testing the voltage at the amp with a multi-meter. If you see voltage fluctuation, you know it's the culprit.

As for the size of the cable, you'll need to find a wiring chart to compare the number of amps (amperes) you are drawing (look this up in your amplifier manual specs) and the length of the run. For short distances you are probably ok.

Another possibility is that you are pushing the amp beyond its limits or you have another set of speakers that are causing the amp channels to clip.

Last, but not least, what size wire are you running to your tower speakers? If it's not big enough, you could be experiencing some issues as well.

spharis posted some wiring charts on here somewhere, just search for them.

[chpthril]

In short, a 1.5' run of 8ga is fine for the 650.4

The manual actually list 8a as the minimum wire size.

[wetsounds1]

Jeff T,

Sounds like you are clipping your amp.

Our tower speakers have a protection built into the crossover to attenuate the horn when the crossover sees a clipped signal. (which is why you mention they sound muffled, the mid bass still plays but no horn, the mid bass can take more abuse than the horn) The horn will mute until the signal is unclipped. Which usually happens when the volume is turned down.

I set it very high so most do not hit it. If you are hitting it. Back down your gains on you amp. You are putting out distortion which is what kills speakers and this protection is in there so you don't blow them.

You should also look at what max volume your head unit is on etc..

Here is a step by step I have posted before on setting gains. Follow this and you will never hit it again.

Setting the gains on an amplifier.

1)Unplug all the RCA’s. Turn all the gains down.

2) Turn the radio up to find the maximum volume. Set the system with the head unit volume at 80 to 85% of max. This is the loudest the radio should go. Radios will create distortion the higher the volume is turned up. Which will create distortion on the output signal before reaching the amps. So find a safe easy to remember volume. If the head unit is 35. Max should be 28 to 30. If the head unit is 40. Maximum should be 30 to 35 and so on.

3) Once you have found the maximum volume set point. Turn the radio back down. Use a test CD that you are familiar with.

4) Plug in just the RCA’s for the in boat speakers. Set the high pass crossover at around 80HZ to 100HZ.

5) Turn the radio up to the max safe level found in step 2.

6) Slowly turn the gain up until you hear the speakers distort. Slowly back off the gain from that point a small amount until you hear the speakers play as loud as they can with no distortion.

7) Unplug the RCA’s from that amp and plug the RCA’s into the amp running the tower speakers. Set the high pass crossover on the amp for the tower speakers at 80HZ to 100HZ.

8) Slowly turn the gain up until you hear the speakers distort. Slowly back off the gain from that point a small amount until you hear the speakers play as loud as they can with no distortion.

9) Unplug the RCA’s from that amp and plug the RCA’s into the amp running the subwoofer. Set the low pass crossover on the amp for the subwoofer at 80HZ. If there is a bass boost knob. Turn that knob all the way up. (as this is what most people will do anyway so you can set the system safely with no worries that they will blow anything)

10) Slowly turn the gain up until you hear the speakers distort. Slowly back off the gain from that point a small amount until you hear the speakers play as loud as they can with no distortion.

11) Turn the radio back down and plug in all RCA’s and do a final check with everything playing. You should now have the gains set at “unity” Meaning they are all at the same level and you are matched across the board.

12) Note that you can adjust the high pass and low pass filters to tailor the sound to each boat. As you can set the high pass higher to get more volume but at the expense of losing some low end mid bass.


Tim
Wet Sounds

[philwsailz]

X2

Jeff T-

There is no issue with your power wire sizing, and the problem you describe would not be due to the wiring.

Tim is on it; follow his recommendations for re-checking gain.


Let me add this though, Excessive bass signal from your head unit can be causing the amps to clip prematurely.


If you have your BASS tone control turned way up, AND you have LOUDNESS or BASS BOOST turned ON at the head unit you need to reset everything to OFF or as "flat" a setting as possible for setting the system up per Tim's instructions AND for normal listening. In fact, do this for bass, mid and treble controls. That is where the radio is going to put out the cleanest signal, which will give your amps the easiest signal to work with.

These low frequency "enhancers" that are provided in a lot of head units are really bad when used to excess. They just cause everything to work harder than necessary.


If you find that you need more bass at flat settings, you can turn these on a little with very little bad effect, but if you find you really have to turn the bass controls way up, it should be telling you that you need more subwoofer(s) and maybe additional amplification to drive them.

You might find that adjusting the gain up a little on the subwoofer amp section, or adjusting gain down on the full-range amp sections provides a better tonal balance for your ears, without the need for adjusting things at the head unit to get more bass.

[Jeff T]

Thanks everyone. The HU settings are off, but i will double check. I will fix the gain settings.

[philwsailz]

Thanks everyone. The HU settings are off, but i will double check. I will fix the gain settings.

Pay particular attention to Tim's item 12. If you have not engaged the hi-pass crossovers on your tower speaker amp, it can cause you problems.

An initial setting that makes sense to me would be somewhere in the 50-80 Hz range hi-pass, limiting bass for the tower speakears.

Double check though with Tim for an ideal hi-pass crossover setting for your 80's

[Jeff T]

ok, so here is a question. My amp has two amps built in (amp 1 and 2). Each has it own set of controls (gain, xover, etc.). I have the RCA lead split so that each amp is receiving a signal.

So, do i adjust both gain control knobs together at the same time, or one then the other?

[philwsailz]

If one thinks about it, each half of the amp is really a stereo amp. It is jus that the two stereo amps share a common power supply.

If you are bridging a pair of Pro 80's, one speaker will be on Amp1 and one speaker will be on Amp2. You can go through the gain setup procedure for the one of the speakers, and then the other.

If you have four pro 80's, a similar situation will be there, and you can adjust amp1 and then amp 2.

The benefit in doing both at the same time is to counteract any potential power supply sag; the common power supply is the key issue here. You might find that you set amp 1 up for clean, and then turn amp 2 up to a similar gain setting that both clip. If that is the case, turn both gain controls down a little at the same time to a similar clean non-clipped gain setting. It is not that complicated, and while it can be intimidating, it is not a huge deal to goof up a little in the process, as long as the end result is clean sound for all channels at the same time.
You really should have no concern about damage either way.

[chpthril]

ok, so here is a question. My amp has two amps built in (amp 1 and 2). Each has it own set of controls (gain, xover, etc.). I have the RCA lead split so that each amp is receiving a signal.

So, do i adjust both gain control knobs together at the same time, or one then the other?

Completely unrelated to your problem, but if you have a ZX series 650.4, correct me if i'm wrong Phil, you shouldn't need to split the RCA's, you just need 1 set of RCA's going into Amp1

[philwsailz]

Completely unrelated to your problem, but if you have a ZX series 650.4, correct me if i'm wrong Phil, you shouldn't need to split the RCA's, you just need 1 set of RCA's going into Amp1

Depends on if you are bridging, and whether or not you want stereo sound.

If you are bridging, and use the internal signal pass through, you will be plugging left and right RCA's both into amp1. Amp one will be bridged, and thererfore will be playing a mono-summed signal.

See it?