28 replies to this topic

[Jackman]

It seems to be big bass notes, it seems to cut out then play them after so its deffo a voltate/amps problem.

Got a few things to check. I know my old system used to do it too but ive come to a point where i should sort it instead of ignoring it.

[daemonchild]

What speaker wire are you using? Nice thick stuff, or thin stuff?
Just wondering if you're trying to put too many amps (BIG bass note + loud) down a high impedance wire (thin) and this is causing a protection circuit to pop? Almost like the wire isn't connected.

Just an idea.

[Jackman]

Thick stuff to the sub then the cable that came with the other speakers connected to the amp. (According to the audio shop they are more than enough)

The other speakers id say medium size.

[pbrain]

Yes.

That ohm things clever but id expect it to cut out randomly not before a big bass note?

Big bass notes are when the amplifier is pushing at most, so this the most likely time to pass out! have you measured the voltage at the back of the head unit? most HU will run from 10-16v. when engine running there should be 13.8+v at the battery.

if after all the checks it still does it, it could well be a faulty HU...loads of potiental problems such as worn out amp chip, capacitor fault, loose solder joint etc. try another HU if possible.

[Jackman]

Head unit is under a year old and the old head unit did it with a differnt amp. Im deffo going towards a feed problem to the head unit or a battery problem.

[pbrain]

ok. so that rules HU as the cause somewhat (as long as the problem hasn't caused any damage). now check speaker cables and supply cables for shorts, damage, rusty/corroded/dirty or loose connections.

[Jackman]

Will do, job for tomorrow night

I do believe its a feed problem as i turned the heater on today and the surge turned the radio off (Could do with a bigger battery anyway)

[M44K TS]

I had the same problem a few years ago, turns out it was to do with the earth for the head unit, where it earths itself to the car body, it had corroded, so a fresh earthing point sorted it. I think if it was a speaker shorting out, the headunit ould still be powered up but just no sound, (i'm currently having problems in the Maserati with this as the speaker cut outs are very shallow.

[Jackman]

Right Update for you all.

I think ive solved it, big bassy song on, volume upto 20 and nothing.

Wires, same thickness from live to radio and earth to radio - not that.
Speaker shorts - None, wrapped the rear ones in insulation tape to make sure, still did it.
Thickness of wires from the HU to speakers fine.

Removed the rear speaker connection as they sounded "funny". - Can turn the volume up and no cutting out.

What do people think, have the speakers died? (They are on the rear shelf above the sub, recon that may have killed um?) They were second hand before i got them so have had a fair bit of use.

Ta

Jackman

[mintom]

Good thick enough and correct supply connections to head (there can be two power connections, one for battery etc to keep clock going, and the other with ignition to supply main power), check. Good thick enough and correct earth connections to the head, check.

Sounds like it's driving two of your speakers well (assuming you have four speakers). disconnect these and try the other two speakers on the same channels of your head unit - working the same? This will sanity check both your other speakers.

Assuming your head unit has four individual channel outputs with the same rating, now connect the speakers you know work, to the other two channels of the head. Do they still sound the same? that could point to the head unit.

Second possibility, when I last wired up a head unit (aeons ago, not a car hifi buff in the mini, just has to sound ok), I didn't get my connections right the first time, when I mapped the power and speaker connections to the iso connector to go to the head unit. Make sure all the connections +/- to the speakers are directly and individually connected to the head, and no earths are commoned up or anything silly like that. Sorry for sounding dumb, but it's just a logical sanity check I would do as an amateur.

One other thing, your sub isn't connected to anything at present is it? I take it that would just have something like a line out from the head with its own amp? these sorts of things just worth disconnecting while diagnosing other stuff.

[Edit - I'm only thinking of the simplest setup (going on my limited knowledge) and if you've got crossovers or anything like then somebody else is going to have a better idea!]

Edited by mintom, 25 September 2009 - 08:31 AM.

[Jackman]

Right head has 4x50 outputs, 3 aux outputs (2 normal one sub)

Head goes to 2 6x9's and 2 13cm (disconnected)

One output via amp goes to 2 13cm components at the front and other via amp goes to the sub.

Tried the disconnecitng of the 6x9's too and it still cut out. Im thinking that there is a problem with the rear 13's in the parcel shelf.

[g8ndj]

I had the same problem it ended up being to much power being taken from the battery. give it a charge and see what happens. It solved my problems.

[leaky]

Mine does this. I thought it was the battery as well because after a few time of doing it I then couldn't start the engine. When I got the rest of the stuff of my install I'm going to buy a big pug diesel battery as I'm told their the best ones for a mini. I also don't have an amp. Just the head unit and 4 speakers.

[pbrain]

Mine does this. I thought it was the battery as well because after a few time of doing it I then couldn't start the engine. When I got the rest of the stuff of my install I'm going to buy a big pug diesel battery as I'm told their the best ones for a mini. I also don't have an amp. Just the head unit and 4 speakers.

don't forget...you can only get out what you put in! if you have a big battery and it runs down, it'll take a fair amount of current to recharge. i'd invest in a red-top (you can get these cheaper now) faster recharge and give's better starting at lower charge levels and fit's in the mini's battery hole. also if you plan on more audio gear, upgrade the alternator if possible.