mx5cartalk.com

So I have a simple car audio set up.

Clarion head unit with two rca out. heading to a 4 channel PA amp.

Front channels running 6.5 inch splits and rear running 10 pioneer sub.

head unit is only running the head rest speakers.

ok, the problem is when the bass kicks in in some songs.. general dance music with the constant thudding is fine, but when you move to more RnB and more dynamic bass songs where a deeper bass note is held for longer intervals, the system draws too much power from the car and causes and idle dip.

how can a stabilize it so this doesn't happen? its very annoying.

easiest fix is to just get rid of the sub or tune down the volume but that won't work for me.

Sounds like you are drawing more power than the cars electrical system can handle.

I'm sure someone will know the real answer, but I would think a bigger alternator or a great big capacitor which covers the power spikes that the amp is drawing.

http://www.onlinecaraudio.info/Car_Audi ... _Them.html

J

yep farad capacitor is the go

mine i think was 299 fusion one

but there are alot of different brands out there and depending on your system will deppend on how bigger unit you need!

The Capacitor will only be a band-aid sollution to the problem of not enough power being provided to the amp. If you were to have a long note the capacitor will be drawn down to zero quite quickly. Have you got at least 4GA power and earth wire with an equally capable fuse? Good earth connection? Decent battery? These would be my first point of call.

Also, if the headunit with not much power capacity for the main channels, when you drive them hard you'll draw current away from the RCA outputs. It's unlikely to be this one though, but you could test by disconnecting the headrest speakers or fading to the RCA's, usually rear.

get a high drain battery normally solves it, earthing could be a problem but it's unlikely since the battery is in the boot and most amps are earthed to battery connection or to battery earth

read this
http://www.caraudioaustralia.com/forums ... opic=45079

1. Get a better battery. No, its doesn't need to be a $500 Optima or Odyssey, just a nice Exide or Century or SuperCharge with 500+CCA & 120+ minutes reserve.. budget $120-180.

2. Upgrade the earths. Buy 4 gauge cable. Replace the battery -ve to chassis earth and engine block to chassis earth straps with the 4g. While your at it, run another 4g from the battery -ve to the firewall.

3. Upgrade the earth cables on your amps to 4g. The +ve should also be 4g.

4. Get an auto-electrician to check out the alternator and see how healthy it. You can also ask them to upgrade the alternator to battery charge wire to something bigger while you're at it.

5. Clean your battery terminals & clamps with steel wool or sand paper for a good clean connection.

In 99% of cases these simple steps will solve any problems you have with lights dimming, etc. Caps are worthless, spend the money on cable or battery upgrades.

As I understand it the earth from the amp should always go to the body of the car regardless of where the battery is. I'd say this would be to simplify the body/-ve connection. Not upgrading the body to -ve terminal is like using a straw on your air intake. No matter how powerful your turbo is it can't get enough air.

Alternator is less likely to be the issue as the majority of the instantaneous current comes from the battery or capacity, with the alterator topping the battery up.

actually one of the most common advised ways to reduce \"noise\" is to do a direct connection from the headunit to the battery, the reason why this isn't normally done is the resistance of the wire running from an amp in the boot to the battery under the bonnet is so long it's a pain to run and the resistance gets too high over such a long distance in wire because the cross-sectional area is small compared to the car body

the battery itself actually acts like a capacitor since it's impossible to make a totally DC power supply directly from a generator/alternater due to the way they work

but the stock battery grounding should be upgraded if you run at high power from it because stock it is only 8 gauge

also maybe it's just your amp using too much power, most car amps are class A or class AB, not so common is class D amps
class A amps are only 20-30% efficient this means for every 100W input you only get 20-30W output so running high powers will create alot of drain
class AB amps are more efficent at about 40%
Class D amps are in a class of their own no pun intended they are just soo Efficent in comparison more than twice as efficent as a Class AB amp so they use alot less input power for the same output

re the battery, you can get an odyssey from mania for $260. i got one a coupl e of weeks ago and it's been great so far. my radio used to cut out every now and again and that has not happened since i got the odyssey. the cutting out may have been due to the dodgey terminals on my old battery more than the fact that the radio was drawing too much current tho.
actually the best thing about this battery is that is so small and you can mount it laying down on it's side. so i can now fit a guitar hardcase in the boot.

SM wrote:actually one of the most common advised ways to reduce "noise" is to do a direct connection from the headunit to the battery, the reason why this isn't normally done is the resistance of the wire running from an amp in the boot to the battery under the bonnet is so long it's a pain to run and the resistance gets too high over such a long distance in wire because the cross-sectional area is small compared to the car body

the battery itself actually acts like a capacitor since it's impossible to make a totally DC power supply directly from a generator/alternater due to the way they work

but the stock battery grounding should be upgraded if you run at high power from it because stock it is only 8 gauge

I've heard of that one to, but I thought it worked the other way around. In anycase, it's likely not the source of the problem, rather the quality of the earth/-ve connection is.

SM wrote:also maybe it's just your amp using too much power, most car amps are class A or class AB, not so common is class D amps
class A amps are only 20-30% efficient this means for every 100W input you only get 20-30W output so running high powers will create alot of drain
class AB amps are more efficent at about 40%
Class D amps are in a class of their own no pun intended they are just soo Efficent in comparison more than twice as efficent as a Class AB amp so they use alot less input power for the same output

Hence your Class-D reference below???

Class D are the best for Subs, however as their switching speed is limited to a lower range comapred to an A or B class amp, they are not well suited to full-range amplification. Great bang for your buck though.

class D kinda sounds like ass tho doesn't it?

i'm probly speaking outta my ass, but i thought AB was the way to go for sound quality? (or pure class A preferably, but they are too inneficient for car audio as you mentioned)

edit - yeah, basically what brad said

yea Class A was the one for good quality but it was inefficent
pure class B had too much distortion
Class D is efficent but the costs are high due to the complex output filter that they need, originally they wern't great but now they are close to Class A for Quality