Need some feedback from those with knowledge since I am lacking when it comes to car audio.

I'm thinking of installing Polk Audio db6501's (6.5 inch components) on the front and leaving the stocks on the rear. My head unit would be a Pioneer AVIC D3 pushing out 50W RMS and no external amp.

Without an external amp, would the components on the front work OK or do I need more power?

Is leaving the rear stocks something you would normally do or should these be upgraded as well?

Comments are appreciated!

Martin

 

I am not sure about powering the components with the headunit, but usually you want to power them with an amp. IMO, you definitely do not need to upgrade the rear speakers. I think the setup will sound good. You can always try it without the amp first and then put in the amp later if you wish. My only concern is that by not powering the components properly, they may get damaged over time?! Can someone please clarify this?

 

Actually, you won't have any problems powering your comps with your head unit.

Your Polk comps are rated to be powered anywhere between 10 and 100w RMS, so just drop 'em in! I'd seriously weigh the pros and cons of powering them by an amp...a 50w gain vs. an expensive and time-consuming install. Your call in the end, though!

 

There are small installs of a simple 125watt (peak) amplifier and will make a difference. I have seen some cute and small JL amplifiers that are the size of your bible, and should fit nicely. Any aftermarket amp should do btw.

and Lambert is right, your headunit should be more than enough to power those components, but you wont be using their most potential.

 

Headunits do not really produce a clean 50 watts rms. The most you could hope to get out of it with a reasonable amount of distortion is about 18-20 watts. If you are going to take the time to upgrade the speakers do it right and put an amp on them as well.

 

cuteboi and chase are right - there are small amps that would supply cleaner watts to your comps in (relatively) inexpensive packages. I wouldn't call myself an expert, of course - but I know what my experience has been with amps/subs/head units/aftermarket speakers, and it is a lot of work running cables and wire to the amp, through the firewall to the battery, and (not least of all) to the speakers in the doors. You could get it professionally installed, of course, but that adds more dollars to the deal. Keep in mind that you have a killer head unit...that Pioneer is not low-end equipment, and the quality of its output may surprise you.

Another trick to doing it correctly is choosing a decent amp and not being tempted by cheap, trash brands. Learning the difference is a lot of research, and you will only get clean watts with a trusted brand. JL, Precision Power, Memphis, etc are good companies but even 100Wx2 amps can run ya up to $200 - maybe even more.

I'm just trying to match my suggestions to your situation and current knowledge. Many people would not consider installing a great component set and running it off the head unit, but like I say - weigh the pros and cons. You, like I, might actually enjoy the process and challenge of the install. My first project involved running all four speakers in my car off one 4-channel amp in the trunk, and though it took me 8 hours to finish, I felt mighty proud when I heard those first notes playing loud and clear...

 

My polk db6501's sound good with the stock head unit, but not great. I spoke to several car audio shops in the area and they all said the same things; RMS rating of the components should be matched as closely as possible by the head unit/ amp; too little power WILL damage the speakers over time, not to mention you won't ever hear their potential; rear speakers are for fill and most SQ cars have stock or none at all; quality of the amp matters big time. I just decided to change mine,(fronts), I'm going with Eclipse SC6500's powered by a Cadence M2000 amp, ( amp's don't get much better than this, and on their website it is only $119!!! about $600 OFF thier original price!). Those Polk's are pretty serious and SHOULD be powered with about 100RMS watts.

 

Too little power will not hurt speakers. What do you think happens when you run your speakers at low volume? It's the same thing as running less power.

However, if you have too little power you will be tempted to turn up the volume to the point of clipping. When the signal is clipped the speaker will stay at each limit of its excursion for a longer time which limits cooling, and will have extra average power over time. Clipping can cause thermal failure of the speaker if you get close to it's normal limits. You probably wouldn't kill a decent set of components with your headunit even if you clipped it for a prolonged period of time as they should have enough thermal handling to take it.

 

As it was said to me by several professional installers, " power and volume are NOT the same"
Please note that I am NOT a professional when it comes to stereo's, but I try to inform myself as much as possible about anything I attempt, and this is a conversation I had with several pro's just last week because I wouldn't believe that power and volume weren't the same.

 

Well, apparently they aren't true professionals then.

 

Interesting... some of that info was second hand from a top 5 ranking installer in the country for several years in row in the late 90's... but, like I said I m NOT a pro, but I am changing my setup based on thier recomendations, let you know how it turns out.

 

All it takes is a simple understanding of electricity to see how absurd that idea is. Just trying to help you out.

 

Do you mean like the "simple understanding" that led you to the incorrect assumption on my amp wiring?

 

Ok, 95% of sound shops have no idea what they are talking about. Read this with an open mind, and try to forget what you think you know.

Too Little Power Blowing Speakers





A post by Manville Smith from JL audio.

The only thing that thermally damages speakers is power... more specifically: average power over time.

I'll explain...

If you take a given amplifier, let's say 100 watts and operate it just below clipping with music material, the "Crest Factor" of the amplifier's output is equivalent to the "Crest Factor" of the program material.

"Crest Factor" is the difference between the average level of the signal and its peak level. For example, a pure sine wave has a "crest factor" of 3dB, meaning that it's peak level is 3dB higher than its average level. We all know that 3dB represents a power factor of 2, so another way to look at it is that the peak power of the signal is twice that of its average level. So, if we play a sine wave on our 100 watt amplifier, just below its clipping level, the average power (over time) the speaker is needing to dissipate is 50 watts.

A true square wave, by comparison, has a crest factor of 0db, so it has equal average and peak power. Our 100 watt amplifier, playing a square wave, unclipped, into our speaker requires that the speaker dissipates 100 watts of power (twice the heat as a sine wave).

Music has a significantly higher crest factor than sine waves or square waves. A highly dynamic recording (Sheffield Lab, Chesky, etc.) typically has a crest factor of 20dB or more, meaning that its average power is 100 times lower than its peak power. So, if we play our 100 watt amplifier just below clipping with the typical audiophile recording our speaker is only needing to dissipate 1 watt of average power over time.

Modern commercial recordings typically exhibit crest factors of around 10dB, meaning that the average power is 10 times lower than the peak power. So, our 100 watt amp just below clipping would deliver an average power over time of 10 watts that the speaker has to dissipate.

Okay, so what happens when we clip the amplifier (which we all do at times). When the amplifier enters into clipping, the peak power no longer increases, but here's the KEY... THE AVERAGE POWER CONTINUES TO INCREASE. We can often tolerate a fair amount of clipping... as much as 10 dB or more above clipping with a reasonably dynamic recording... a bit less with a compressed commercial recording.

So, if we turn the volume up 10dB higher than the clipping level with our Sheffield Lab recording, we have now reduced the crest factor of the signal reaching the speakers by 10dB... so instead of needing to dissipate 1 watt average, we are asking the speaker to dissipate 10 watts average, and we're probably ok.

If we turn up the volume 6dB past clipping on a compressed commercial recording (or bass music recording), we have taken the crest factor of the signal from a starting point of 10dB to only 4dB, asking the speaker to dissipate an average power of 40 watts instead of 10 watts... that's FOUR TIMES the average power, which generates four times the heat.

SO, in most cases, the reason clipping can damage a speaker really has nothing to do with anything other than an increase in average power over time. It's really not the shape of the wave or distortion... it's simply more power over time.

When someone plays Bass Mekanik clean (unclipped) on a 1000 watt amplifier the average power is 100 watts (10dB crest factor). You can also make 100 watts average with Bass Mekanik by heavily clipping a 200 watt amplifier.

If someone is blowing a woofer with 200 watts of power due to a lack of restraint with the volume control... they will blow it even faster with a 1000 watt amplifier because they will probably turn it up even more and now they have more power to play with... this is the recipe for aroma of voice coil.

When woofers are rated for power, an unclipped signal is assumed. We use test signal with a crest factor of 6dB for power testing and can run a speaker at its rated power for hours and hours on end without thermal or mechanical failure. For example, a W1v2 can dissipate 150 watts average power for eight hours or more with signal peaks of 600 watts. So, we rate the speaker for 150W continuous power. This way, when a customer needs to choose an amp for it, they will hopefully choose one that can make about 150 W clean power... Even if they clip the bejeezus out of that amplifier, it is unlikely that the speaker will fail thermally. This is a conservative method, but it needs to account for the high cabin temperatures in a car (think Arizona in the summer) which significantly impacts heat dissipation in the speaker. A top plate that starts at 150 degrees F is not as effective at removing heat as one that starts at 72 degrees F in the lab... and this affects the ramp up of heat in the coil.

DISCLAIMER: The frequency components of clipping can affect tweeters due to their low inductance and lack of low-pass filtering. Clipping essentially raises the average power of high frequencies to a point that can damage tweeters... Woofers and midranges couldn't care less about these high frequency components because their filtering and/or inherent inductance knocks that stuff out of the picture.

Best regards,

Manville Smith
JL Audio, Inc.


I would clarify that futher, sprexumn....

The fact that a signal is clipped does not make it inherently damaging... if the average power of the clipped signal is low it won't ever damage a speaker. At higher power levels, the fact that a clipped signal carries more average power over time can result in damage.

The fact that tweeters have low inductance, do not employ low-pass filters and have small, delicate voice coils makes them more susceptible to damage from a clipped signal than a woofer or mid.

Does that make sense?

It just points out that the old statement of an amp that is too small will damage speakers more than a more powerful amp is entirely dependent on the use of each amp... if you clip both amps to the same extent, the more powerful one will blow speakers faster.... but it is possible to make a small amp operated into clipping produce as much average power as an unclipped larger amp (even though the peak power is greater on the big amp).

When you clip an amp you not only increase distortion, you also compress the dynamic range of the signal... the distortion isn't what kills the speakers (except tweeters in some cases)... it's the dynamic range compression that really does it.

Best regards,

Manville Smith
JL Audio, Inc.

 

Thank you for the link, can't wait to show it to to a few people. I always love statements backed up by data.

 

More data... LOVE IT. Thank you again

 

Yes! You've seen the light !

 

Do you agree with the other ealier mentioned points that I was told by the shops? And they also mentioned that I would be well advised to purchase the " Cleansweep" by JL ,as a matter of fact, if I planned on keeping the factory head unit? Thank you for any info.

 

I agree with not running rear speakers and using high quality amps. I would recommend replacing the Headunit over using something like the Cleansweep. Although, if you have to go that route I like the Rockford Fosgate 3Sixty.2 .

 

If you are installing components please amp them, otherwise they will sound like crap. You bought a nice headunit and speakers, dont skimp on the last part.