Discovered something weird about my setup today

[bballer123 10+ year member]

Today I was in the car with a friend and I thought I had blown one of my front speakers on the right side. So I adjust the settings so music is on the right side only. The bass must have jumped by about 10 DB just by having it set to that one side. I thought maybe because there were less vocals (only one side playing music), I just noticed more bass. That was wrong. I opened the trunk of my suv and saw that the subwoofer was moving considerably more than it has ever before. When I put the balance back to normal, the bass dropped back to normal also.

Before I added the subwoofer, I had a stock 6 speaker monsoon system in my car. When I added the sub, the install shop said they could add it straight to the stock radio/cd/headunit...whatever you wanna call it.

I have a 12" type r hooked up to an alpine m350 amp.

So I was just wondering, why would something like this happen?

Thanks.

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[KaeZoo 10+ year member]

It's sounds like the line-out converter or high level input they used to provide a signal for the amplifer was mis-wired. If they connected the two channels in opposite polarity, it would kill the signal when it was summed by the mono amp. The install shop should be able to fix it very quickly.

 

[bballer123 10+ year member]

The subwoofer sounded strong and clean when the balance is in the middle but even louder when the balance is to the left or right side.

Would it still kill the signal?

I dont know anything about wiring or electrical stuff, but would is it possible that because the signal is being sent to less speakers, the subwoofer is actually recieving more power or a stronger signal?

 

[Blunt 10+ year member]

sounds outta phase to me

 

[KaeZoo 10+ year member]

Are there RCA connectors plugged into the amp? If so, unplug one of the two RCA plugs and see if you get the same effect. If it gets louder, they miswired the LOC.

 

[RandyJ 10+ year member]

Here is the thing, he is using a LOC on a stock head unit, right? Therefor, there is no dedicated sub out, which means that his amplifier is receiving a signal from stereo. This also means that the out is now a fading-out. It will perform just like the speakers do now, because it is on the same line as the speakers. When the balance is all the way rightm the full signal is being sent to the right side, as well as the amp, vice versa for the left. If you have the materials, use a 2chan amp and two speakers, and you will be able to clearly see the difference.

 

[KaeZoo 10+ year member]

Here is the thing, he is using a LOC on a stock head unit, right? Therefor, there is no dedicated sub out, which means that his amplifier is receiving a signal from stereo. This also means that the out is now a fading-out. It will perform just like the speakers do now, because it is on the same line as the speakers. When the balance is all the way rightm the full signal is being sent to the right side, as well as the amp, vice versa for the left. If you have the materials, use a 2chan amp and two speakers, and you will be able to clearly see the difference.

Balancing a signal all the way to the right doesn't increase the output on the right channel (compared to having the balance centered). It just attenuates the left channel. Were that not true, then an amplifier would never put out its full rated power when playing both channels at once.

When you connect a mono amplifier to a LOC wired to the left and right speakers, it's really no different than connecting it to the front or rear pre-outs on a head unit, which is done all the time. The only difference is that it's not possible for a left and right pre-out to be out of phase with each other. It is possible to wire a LOC so the outputs are out of phase, and the result would be what he's describing.

 

[Blunt 10+ year member]

Balancing a signal all the way to the right doesn't increase the output on the right channel (compared to having the balance centered). It just attenuates the left channel. Were that not true, then an amplifier would never put out its full rated power when playing both channels at once.
When you connect a mono amplifier to a LOC wired to the left and right speakers, it's really no different than connecting it to the front or rear pre-outs on a head unit, which is done all the time. The only difference is that it's not possible for a left and right pre-out to be out of phase with each other. It is possible to wire a LOC so the outputs are out of phase, and the result would be what he's describing.

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[bballer123 10+ year member]

Balancing a signal all the way to the right doesn't increase the output on the right channel (compared to having the balance centered). It just attenuates the left channel. Were that not true, then an amplifier would never put out its full rated power when playing both channels at once.

Yeah when I balance it to the right/left the individual speakers dont get any louder. Only the subwoofer increases in volume.

I went into the shop that did my install and they said it is normal because it is picking up both channels in the subwoofer. He said the there are 2 ways to get around this. Have it only wired to the right/left side which will miss some of the beats in the songs. Or get an aftermarket HU.

I didn't really understand why the output of the subwoofer would decrease by having it playing both channels. I would like to trust him, but as little as I understand what you guys are saying, his reasoning makes even less sense.

What do you guys think of what he said?

THanks.

 

[KaeZoo 10+ year member]

His explanation doesn't cut it. It's not normal for a mono amp to reduce its power output when it's connected to a stereo signal, except under rare conditions when the bass passages in a song are recorded out of phase for effect. You're describing a power drop that's visible to your eye when you're looking at the subwoofer. That's a pretty substantial difference. It should not be doing that. The input was miswired, pure and simple.

Are there RCA cables connected to your amp, or was it connected through the high-level input plug?

I noticed on a post of yours in another topic, you mentioned that your amplifier has the gain set near max and the bass boost all the way up. Usually when I install an amp on a line-out converter, I can keep the gain pretty low. If you need a maxed gain and high bass boost to get decent bass from a 12-inch Type R in the back of an SUV, that's another clue that something's wrong.

I think when you finally get the problem fixed, you're going to be amazed at what you've been missing all this time.

 

[bballer123 10+ year member]

I think when you finally get the problem fixed, you're going to be amazed at what you've been missing all this time.

Well I took what the install guy said into consideration...somewhat. So today, I took the left RCA connector out of the amp. Right when I did this, the subwoofer started bouncing a lot more than when it connected with both Right and Left RCA.

Now I am really amazed by how loud this is. I always read on here that the type-r could produce loud bass and previous to unplugging that left RCA, I thought I was just expecting too much out of only 350 watts. It is plenty louder than my friends who have 1200 watts rms and 2 12's.

My only concern - is this going to hurt the amp/sub at all?

Thanks

 

[Silver 10+ year member]

Are you leaving one RCA unplugged?

Get that shiz fixxed.

 

[bballer123 10+ year member]

The way to fix it is to get an aftermarket head unit. I don't know if I can get one anytime soon.

Will it hurt anything by leaving it unplugged? I know it's weird and kinda ghetto, but it sounded better and the amp is hidden behind the sub box.

THanks.

 

[KaeZoo 10+ year member]

The way to fix it is to take it back to the shop and make them wire the LOC correctly. If it's a chain store, you can try taking it to a different store location so they don't have a motive to pretend it was done right the first time. If it's an independent shop, talk to the manager. The simple fact is that your system wasn't wired correctly. They owe you a fix.

 

[bballer123 10+ year member]

I think I did talk with the manager/owner. It is Il Style Audio in Arlington Heights just in case anyone around Chicago was wondering. My dad is not on good terms with the guy that I talked with because he yelled at the installer about a couple things that the installer did that my dad was not happy with.

It may have been that he was just trying to brush me off and get rid of me.

To check the wiring of the LOC would the front panel area have to be taken off? Or is it something that a friend could do?

When I talked to the guy on the phone, he said that the LOC might be miswired and it would take a max 20/30 minutes to fix it. When he came out though, I turned on the car and he almost immediately said it's 100% normal when I balanced it left/right. He might just not wanna deal with me anymore. Also, if the install place keeps trying to say it's normal for this, where should I go from there.

Not to nag or anything, but is it going to affect anything in a negative way by leaving that left RCA unplugged?

THanks.