help understanding sensitivity, power rating, etc. for upgrade - PeachParts Mercedes-Benz Forum

JHZR2 · #1 02-09-2004, 11:22 PM

Hi,

I havbe an 83 300D with the becker europa head unit. Everything is stock, and I think the sound is quite good. A few friends of mine have also been impressed with the clarity and quality of the sound from my RF CD changer running through that old radio and through the 20 year old speakers.

But I am thinking that at least the front speakers should be replaced. I can tell once in a while, with certain sounds in certain music that the fronts are getting a bit scratchy. The sound still is really good, but the time might be near.

I heard from someone once that when using an unamplified, stock setup, that I really need to watch the sensitivity and power ratings of speakers.

I assume that a speaker with higher sensitivity (lower dB number) will do more in terms of output, and good sounding output at that than one with a lesser sensitivity, which would need something driving it.

SImilarly, for power rating, I suppose that for an unamplified stock system, a speaker set with a lower power rating would be better, as they can do more with the 'weaker' signals that are coming from the headunit, as compared to an amplifier.

Am I more or less correct in saying these things?

If so, then for speaker upgrades, I would be looking for speakers with the best sensitivity and lowest power rating. Something with specs of 85dB and 2-20W would be preferable to something with specs of 90dB and 10-50W, right?

Any help and clarification would be really great.

Thanks,

JMH

#2 02-10-2004, 11:37 AM

Hi JMH.

Q1: NO.

Q2: NO.

The higher the sensitivity the better.

A full range speaker should not be adversely
affected if driven by a low powered head unit.

Only for subwoofers could this cause problems.
Underpowering a subwoofer is as bad as
overpowering it.

This doesn't mean that you should get 300w
speakers.
But getting 50w speakers should cause no
problems.
Just invest in good quality speakers(MB quart,rainbow,
boston accoustics and the like) and you'll hear a clear
difference over the stock speakers.
So 90dB and 10-50W should be good.

Louis.

Zeus · #3 02-11-2004, 04:08 PM

The higher the sensitivity, the less power (watts) is need to produce a given level of sound from the speaker. So 92dB is better than 80dB in that you need less power to produce a given sound level with the 92dB speaker, as compared to the 80dB.

Speaker power ratings are usually deceptive. It seems that the cheaper the speaker, the higher the power rating...lol. Is the rating 'peak' watts or 'RMS'? If it says 100W on the box, that could mean the speaker can handle 100W of peak power (likely) or 100W continuous power (highly unlikely). Don't pay much attention to this rating.

Resistance, actually impedance, is also important - rated in ohms. It represents resistance to the flow of current (amps). So, a higher rating represents a greater resistance to the flow of current, which means you'd want a lower resistance, where possible.

You won't hurt any of your speakers by using your existing head unit unless you drive the head unit amp to clipping by turning up the volume too high, causing distortion.