car stereo output power

[topiman]

Hi

 

I'm using a Kenwood KDC 4547U running on 12V onboard for music:

http://s921.photobucket.com/user/mapleaudio/media/KDC4547U.jpg.html

 

It has 50W output, and I've got 70W speakers attached

 

The sound is great but once I turn it up to around 22 anything with bass gets a bit distorted and above that it actually turns the stereo off / resets it

 

So my question is - does this happen because there's simply not enough power going in (12V) - or is it the stereo / speaker combo ?

 

Looking at other car stereos they all seem to have the same spec in terms of output etc

 

Thanks in advance...

[steelaway]

Hi

 

You need to know what power (watts or amps) the head unit requires and make sure the supply cables are big enough for this load.

They could be substantial.

 

Alex

[Paul C]

Probably a combination of the two - the distortion is simply down to the low quality of the stereo or speakers at high power output, and the turning off will probably be due to low voltage, due to voltage drop along the (I'm guessing long) wires.

 

Were the 50W and 70W ratings peak, RMS, something else? There are a number of different ways of measuring the power, and with peak being the highest number, marketeers tend to promote this.

[Chalky]

Hi

 

I'm using a Kenwood KDC 4547U running on 12V onboard for music:

http://s921.photobucket.com/user/mapleaudio/media/KDC4547U.jpg.html

 

It has 50W output, and I've got 70W speakers attached

 

The sound is great but once I turn it up to around 22 anything with bass gets a bit distorted and above that it actually turns the stereo off / resets it

 

So my question is - does this happen because there's simply not enough power going in (12V) - or is it the stereo / speaker combo ?

 

Looking at other car stereos they all seem to have the same spec in terms of output etc

 

Thanks in advance...

The 50W is a marketing figure - fairly meaningless since there are multiple ways of measuring and specifying it.

 

Most car radios will work down to about 10V. At high levels of bass you'll be drawing a lot of current which could cause the amp to heat up and cause thermal shut down. It could also be poor wiring - the extra current draw will increase the volt drop and cause a brownout of the micro. Fixes are to change the wiring, turn down the bass or listen to something that is less demanding!

 

Also check for transients. Something switching on or off can send a spike down the power feed that can cause the micro processor in the radio to reset.

 

What's the resistance of the speaker? If it's a lot lower than the radio is designed to work with this will also cause the amplifiers in the radio to overheat and shut down.

Edited April 25, 2013 by Chalky

[Justme]

Does the radio have 4 speaker outputs & you are just using 2?

 

One of my older cars had a radio like that & at high levels it did the same. I think to protect the output amps.

 

 

One way to fool it was to use the front to rear fader to turn one channel off completely.

[topiman]

Hi - Cheers for the replies

 

Yes to the dodgy wiring - was looking at that thinking it was a botch - so will re-do that and also try the suggestion about the front-to-rear fader - see if that helps

 

I love bass too much :-)