GolfGTIforum.co.uk
General => Car audio => Topic started by: Len on 12 April 2011, 13:38
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I have a Sony 4 channel amp that works the front door speakers and 2 channels bridged to a sub.
Was checking my sysytem and the front speakers were working fine but the sub wasnt!
So I checked the speaker cable to the sub and was fine. Checked the earth and all the terminals on the amp and all seemed fine.
So in a bit of a tizz I slammed the hatch down hard, the sub sprang into life!
So my question is should I be looking for a new amp?
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Try switching it around. See what happens.
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What? The outputs from the amp? Swap the fronts with the sub? That what you mean?
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Yeah 4ch amp. Ch 1 front left, ch 2 front right, 3&4 sub.
Try 1&2 sub and 3&4 front left and right.
Does it have adjustable x over on all channels? You'd need to lpf 1&2 for the sub and hpf for 3&4 on the fronts.
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The fronts are bass speakers, that make any difference?
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I'm lost now sorry mate.
What do you mean by bass speakers?
I thought you said it was front door speakers.
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I have coax mid/tweets in the dash run off the HU and the front door speakers are mid/BASS run off the amp.
They are SPL Dynamics HF-6.1
Second edit:- 45 - 5000 HZ is the frequency response of those door speakers.
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Ok so your kind of running active.
That's fine. On the 4ch do you have the same controls (filters) on ch1&2 as on ch3&4. If so when you change them over to test ch3&4 just mirror them. Ie make 3&4 the same as 1&3 were and vise versa. Were just trying to establish if the problem happens on all 4 ch or just 2.
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Active?
Not sure!
Think it only has one "volume" control on the amp. Not sure about filters? :undecided:
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All they do is stop nasty freqs speakers don't like destroying them.
You don't want to play a 30Hz tone through a tweeter. It's not going to last very long.
Any luck finding out the problem?
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Nah too busy driving the weekend or partying! :wink: :grin:
Yea I realise about frequency stuff, why the mid/tweets aint amped!
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Oh and I still dont know why my HU cuts out above volume position 20! :angry:
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If it cutting out over a certain level that sounds like the internal amp cant cope with the power needed - how old is this head unit?
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Not sure as I bought it S/H.
Its an Alpine CDA-7894RB with 4x60W int amp.
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Sub is working fine and swapping channels made no difference!
But its still cutting out above 20 on the volume setting! :angry:
Ran it at 20 for a while then moved it up one notch at a time. Lasted at 22 for a while so tried 23 and it cut out right away!
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It's not the outputs then. One down!
Have you another amp to try?
When it cuts out, does the hu turn off or the amp?
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I lost off abit on page two but heres a thought.
Maybe you have damaged the voice coil/motor on the sub so its shorting at certain levels. (would explain the slamming of the boot kicked it into life :wink: )
Have you got an ohm meter handy. A multimeter that measures resistance.
If so disconnect the sub.
Wire the terminals of the sub upto your multimeter. + to +, - to - for example.
Set it so measure resistance.
slowly and evenly/gently near the centre of the sub at the sides of the dustcap Press the sub cone downwards slowly.
The resistance on the meter will change but it should not go really low or to zero. If it does then your sub is causing the system to cut off as its damaged.
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The HU cuts out! Then when you turn it down it comes back.
Yea have multimeter. So the sub speaker totally disconnected? OK will give it a try.
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Maybe test the system with the sub disconnected as well.
Oh I do have another amp, but its a really crap budget amp 4 channel, think its called Jackson. :embarassed:
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I wouldn't of thought the amp would be causing the HU to cut out.
Try running a new earth cable to the HU.
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Hmmm that means pulling the HU out! Absolute bugger to get back in! :angry:
Oh well if I want the volume........
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Hmmmm bit like the blind leading the blind here :wink:
Len have you got your HU wired directly to the battery or just running from the existing dash wiring?
Did you know the 4x60W alpines MUST be wired to the battery due to the high currents they draw?
Although this is unlikely to cause the HU to shutdown it's worth doing to avoid toasty wiring looms.
I would say the cutting out is quite likely due to it simply being a faulty headunit. I have seen this several times in the past, I used to have a kenwood which had a certain volume above which it would simply switch off. It would be interesting to see if the HU switches off when there are no speakers connected to it.
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Yes it is connected direct to the battery, with an inline fuse, although the actual cable is not very meaty and have been meaning to run a new cable.
Will try no speakers then and let ya know!
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Hmmmm bit like the blind leading the blind here
Ok this blind person will shut up and leave. I'll go back to talkaudio were ive helped since 01 and back to the audio forums i moderate.
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Snoopy what's ya TA login?
I'm b-chi. Been on there oodles. Try not to take offense mate, not in the Ta spirit.
How are people going to learn if people aren't willing to help. It's very difficult to fault find over an internet forum.
Don't mean to offend anyone with this next comment. But there are a lot of people on this forum (and others I'm sure), who aren't into audio as much as say you and I, or don't have masses of experience, or have even been told diff info by a shop/installer so think that's right. Who wants to be proven wrong? Last comments aren't relating to this thread.
On another point. Were you on the M40/A34 junction last weekend LEN. Saw a blue 5 dr with gold rims.
Following on from tobz point. Try a different HU to see if it still happens.
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On another point. Were you on the M40/A34 junction last weekend LEN. Saw a blue 5 dr with gold rims.
What Easter weekend? Nah not me! Oh hang on a mo, if was weekend before I was on my way back from Leeds and Charity RR day, on the Sunday about midday. Coming off M40 going south onto the A34. So yea probably was me!
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Yeah that's it.
I got a little excited when I saw it lol.
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Only a little? :grin:
I wasnt really looking around as thats one of the dodgy junctions where folk get in wrong lane, usually but seems they have changed it and actually improved things!
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Well one puzzle solved, kind of!
Cutting out does not happen with engine on!
So it must be some kind of power issue.