Help!!!

[cigarlvr]

I have a 08 Coupe that I have been going round and round with. I had a set of the Boston Pro put in the front and then running a alpine MFP 550 to drive it bridged to just the front. I am using the factory amp to power the back but have a his they can't get rid of. It isn't noticible with the tunes cranked as long as the song is playing but if it song slows down you get the hiss. They are able to get the hiss to go away but the gains have to be turned way down on the system and then no power. I am also using an audio control dql-8. I have had it back several times to the radio place but they can't seem to fix it and they keep saying it is a cheep radio that is just putting out this hiss. I haven't seen anyone else with this problem so I beg for help. They have checked the ground and that is fine. Any Ideas PLEASE???

[jblaust]

try pulling the fuse for the daytime headlights. You can find it by looking in your owners manual and it will tell you which fuse to pull. With the fuse out see if you still have the hiss. I had a similar problem. I took the fuse out and the hiss went away. Something about low voltage pulse power to the daytime lights. You can also just turn on your headlights to make the daytime lights turn off to test this theory.

[jblaust]

I have heard you can use a couple of large magnetic filter collars that go around the power and ground wires to your amp that may filter out this sound. I havent tried it yet. Just been riding without the daytime lights. I didnt like them anyways.

[dking99]

Just out of curiosity, did you bridge the 4 channels into 2 channels and run them each to the component set? Why not keep 4 channels and run one to each of the drivers and one also to each tweeter?

[cigarlvr]

I sure wish it was that simple. The noise is a hiss and light hum sound. No motor noise when reving. Any other ideas?

[cigarlvr]

and only drive with me in the car so didn't care about the back ones.

[JamieJam1AIM]

root of all evel Chheck your RCA's Cheap RCA's will cause hum and hiss especially if they arent tightly bound... Im not saying spend 100+ on Monster cables but go to radio shack first buy a simple set and test the theory.. If that cures the issue then go buy a high quality piece engine noise is from bad ground or a bad amp usually depending on where you grounded the dql or the amp can cause engine noise.. hiss is from processing or transmission wires hence why when you wire a real concert hall you use 3 prong XLR cables not 1/8th inch heads3et cables.. LOL Hope this helps Let me know what you find and we'll see the next step..
JJ

[jblaust]

and only drive with me in the car so didn't care about the back ones.

Did u try pulling the fuse for the daytime lights? My problem was when the volume was low you would hear the hiss/hum through the mids/hi's. You didnt hear it with the volume up. With the fuse pulled for the daytime lights the hiss went away. You can also just turn the head lights on to make the daytime lights turn off. Thats how I found the problem. We checked everything, swapped amps, grounds, rca's, speakers, power source and couldnt fix the problem. We even made sure the power and rca's were on different sides of the car to not make interferance. We also tested moster cables and filters just run across the car for a quick test, nothing helped. Then I noticed when you turn the headlights on and the daytime lights go off that the problem went away. I pulled the daytime headlight fuse and problem was solved until I can find a better solution. I was told magnetic collar filters around the power and ground wires would help. This problem pops up in other cars also with the daytime headlights. I was told it is a low voltage pulse power source going to the daytime lights that creates the hiss/hum sound with the volume turned down.

[cigarlvr]

But no help I could have only wished.

[jblaust]

sorry...it worked for me...

[dking99]

which speakers have the hiss? The fronts or the rears?

[cigarlvr]

The alpine amp is powering the front ones only and the factory is powering the rear but the factory one is a very low level amp so that is the reason it isn't maginifying the sound in the back and no hiss there is what I am being told.

[dking99]

You didnt answer my question...which speakers have the hiss? Front or rears?

I dont know the answer to my question above, but if I were to guess, your fronts have thr hiss...

The fronts and the rears are 100% completely independant of one another right now. The main differences are the two amps powering each set of speakers.

I think you have the gain levels incorrect (fronts) for the output of the stock rear speakers. If your head unit is like mine, for a CD, the volume maxes aout around 20-24...I am not in the car, but I think that is right. Lets say the # is 20.

If this is the case, set the head unit to 20 and use the gain on the amp (fronts) and adjust that to it's highest volume with no distortion. Now both your Alpine amp (fronts) and stock amp (rears) are balanced.

I have no clue what the problem is, but if it is the rears that are hissing, it is not the Alpine amp's fault. If it is the fronts that are hissing, it is not your head unit's fault.

[Accordlover]

Does Active Noise Cancellation have anything to do with this...

[dking99]

How can anyone solve this problem? You havent told us which speakers are hissing!

FRONT or REAR

[cigarlvr]

FRONT are making the hiss and the ANC has been disconected.

[ZedsDead]

I have a very similar setup...

BA Pro 60 in front (sx60 in rear) driven by an Alpine F600.

Couple of things here:

1) The amplifier gain is a control that lets you boost the input signal voltage. The amplifier expects 8 volts and if your input signal is less then that, you must boost the input gain. Input gain settings range from about .5 volts to 8 volts. Using a voltage meter, measure the voltage of the RCAs. If they are at 8 volts, set the amplifier gain at minimum (no boost). If it is less then 8 volts, increase the gain by the relative amount.

If you have 8 volts, and boost if further (to like 12 volts), you will most certainly get noise (hiss).

2) The Pro60 tweeters are metal and extremely bright. When mounted in the upper door and/or dash, they should be set to -4 db. When set to 0db, and in this location, you will hear all hissing.

3) Suspect the High Low converter, these always add noise. Your amp has a built-in Speaker Level input so there is absolutely no need for this item. Run the front speaker output directly in to the amp and set the amps input gain to minimum. Line Level Converters are notorious for adding hiss.

4) These speakers want 125 watts RMS and your amp provides 90 watts RMS. With the input gain set correctly, it will not be as loud as you would expect. You may want to bridge it so that you are feeding 250 watts per channel just be careful not to overheat the speakers. TRUST ME, they can handle the power but if you crank it for long periods of time... the may melt.

Also, remember that this system has DSP and will change the eq at various volume settings. You may want to think about the JL Audio Cleansweep or similar.

[dking99]

ZedsDead...

Is there any advantage to running the tweeters and mid range drivers on seperate channels? In other words, power your Boston Pros with a 4 channel amp...

[ZedsDead]

absolutely and those speakers are specifically designed to do that! You may want to use a seperate, low power amp for them.