54 replies to this topic

[Brams96]

So you have:

HU - Sony 4x45 USB Mp3 Cd jobbie

Alpine MRF T222 (LINK)

Fusion - Encounter 6.5" components
Fli - Integrator 6x9
And a set of dual cone alpine, 4" component speakers

Basically you have too many speakers!

The Alpine amp can drive a 2 or 4ohm load per channel so run the 6.5's from one channel of the amp and the 6x9's from the other, you will have lost any fade/balance between the chanels though, and run the 4" components from the head unit. Otherwise disconnect the 4" components, run the 6.5's from the front channel of the HU and the rear channel goes to the amp and 6x9's.

Either way you should only be driving 4 speakers directly from the HU.

[mymini007]

So you have:

HU - Sony 4x45 USB Mp3 Cd jobbie

Alpine MRF T222 (LINK)

Fusion - Encounter 6.5" components
Fli - Integrator 6x9
And a set of dual cone alpine, 4" component speakers

Basically you have too many speakers!

The Alpine amp can drive a 2 or 4ohm load per channel so run the 6.5's from one channel of the amp and the 6x9's from the other, you will have lost any fade/balance between the chanels though, and run the 4" components from the head unit. Otherwise disconnect the 4" components, run the 6.5's from the front channel of the HU and the rear channel goes to the amp and 6x9's.

Either way you should only be driving 4 speakers directly from the HU.

I thought I was!?!?

The amp is driving the 6x9s and the rest are coming off the HU. just tried to do a diagram on cad but cant work out how to get it up on here.

[Brams96]

The amp is driving the 6x9s and the rest are coming off the HU.

Head unit can drive 4 speakers, yes. But what you're doing is driving the 4" and 6.5" speakers from the head unit AND driving the 6x9's from one of the same channels as one set of speakers so effectively running 4 speakers from 2 of the channels and 2 from the other. The 4 speakers being driven from the 2 channels of the HU are basically making it try and drive a 2 ohm load instead of 4 ohms.

just tried to do a diagram on cad but cant work out how to get it up on here.

If you click on Browse and search for your picture (jpeg are the best) then click UPLOAD.

Have a look at the diagram below for how it should all be wired.

Attached Files

•  Basic_Amp_Wiring_1.JPG   106.91K   17 downloads

Edited by Brams96, 07 June 2010 - 11:44 PM.

[mymini007]

Yes, that looks about right. Will my amp work with option 2 then? I thought I could only run 2 set of speakers from my amp. Would it be worth putting in another amp to option 2? Or just do it as you have drawn?

[Rich.]

Mymini007 is not running a cheap headunit, it can easily power 4 speakers. There is an underlying fault here causing problems.

Which it clearly is doing fine up until a certain level, which is where it kicks in. If you think about it he will be driving 4 speakers probably rated at 100w a piece plus. The headunit will probably be delivering 30w a channel max despite what it says on the box.

This is what i carnt understand about car audio. In the professional audio bussiness, we spec amplifiers with usually double the rated output of the speakers, so its not possible to overload the amplifier. A blown speaker is alot cheaper than a blown amplifier, and a decent sound technician should be able to hear a speaker distorting and know when to turn it down.

So basically i would say this is your problem, your just asking too much from the headunit's amplifier.

Im not sure everything said below is correct. Are you running the output for your amplifier from a pair of phono outputs on the back of the HU rather than one of the speaker channels? If so, running too low of an impedance isnt your problem, as you still technically only running one speaker per channel. If your running the signal from a speaker channel with one of those little gadgets that takes the powererd feed and turns it back into a low voltage singal again then whats said below could be correct, but i would have thought you would just take it out of the AUX output on the back of the HU?

Rich

[mymini007]

Im not sure everything said below is correct. Are you running the output for your amplifier from a pair of phono outputs on the back of the HU rather than one of the speaker channels? If so, running too low of an impedance isnt your problem, as you still technically only running one speaker per channel. If your running the signal from a speaker channel with one of those little gadgets that takes the powererd feed and turns it back into a low voltage singal again then whats said below could be correct, but i would have thought you would just take it out of the AUX output on the back of the HU?

Rich

?

I did not understand a word of that. !

My amp has a big blue double cable that has 2 plugs on each end, red and white I think?
They plug into the amp at one end and the red and white plugs at the HU. There is a small blue wire that goes fron the blue wire on to the hu and to a deely that says remote on the amp. amp is fused and hard wired to the battery.

The 4 speakers in the front are coming off the 4 ports provided by the big black plastic block of wires that were in the car.
Hope that makes sense.

[Rich.]

Right, in which case its not an Impedance problem. Your runnign 4 channels from your H's amp and the seperate amp of the bypassed output, which is fine. I would now almost guarentee that its your overload protection kicking in. The best way to confirm this is to unplug the amplify to reduce the power drain on the electrical system, have the engine running and no other electrical items turned on if possible, then turn the stereo right up, there should be more than enough power available to power the HU to max volume there, so if it still cuts out its the Overload, if it dosnt, then its a voltage drop from the amp drawing so much current, and you would need to upgrade your electrical system.

Rich

[mymini007]

ok, unplugged amp so no power is going to the 6x9s, turned up the hu to 17, think it goes to 30. 17 is as high as i got before it cuts out,

Or do I need to turn the amp off all together?

In which case I will have to wait for the rain to stop.

Edited by mymini007, 08 June 2010 - 04:12 PM.

[Brams96]

Try disconnecting all the speakers and then turning the head unit up and see if it cuts out still, this will tell you if it's the speakers drawing too much power or if the head unit itself is causing the problem. Can you tell us what the model number of the HU is?

[Rich.]

Yep, i agree with that.

Try disconnecting 2 first and see if you can get it to go higher, then none and see if it will crank to full volume.

Rich

[mymini007]

Sony MEXBT3600U



Sony head unit

[mymini007]

Disconnected, two of the 4 speakers, so the HU is running the 4" alpines, and the amp, It cut out once on the way to work this morning, but I came to work on the worlds bumpiest road with no issues, so its not a loose connection, am thinking of getting another amp, and running all the speakers off a 4 channel amp so nothing will be coming from the HU, will this work?

[Rich.]

Should work fine. You will probably find the sound quality will increase aswell providing you use a decent amp.

Rich

[mymini007]

Should work fine. You will probably find the sound quality will increase aswell providing you use a decent amp.

Rich

Just been chatting to the stereo bloke in halfords and he thinks one of the speakers may be cross wired or is shorting out that is making the HU cut out, so I figure if I am fitting a new amp I will have to strip it all down anyway.

Can you recommend a 4 channel amp that will not be too big to blow the speakers, i was looking at a vibe A3 for £99 but I think it may be too big?

[Rich.]

Personally i would take anything someone from halfords tell you with a pinch of salt, but thats just my expierience of them.

Personally i would reccomend the rockford fosgate P300.4. But thats because i love Rockford kit, personally though i dont think you would find a better amp for the money.

http://cgi.ebay.co.u...=item19bb8f76a0

Rich