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View Full Version : components with equal sound distribution. Read This!!



Propel152
11-24-2013, 03:40 PM
Ok, so I recently blew my tweeters to my JBL P660c components. I blew my tweets but my woofers are fine. Now, this could possibly be my fault(wouldn't surprise me). I was using the factory internal crossovers from the Bose system that was previously in my truck. Maybe it was allowing some lower frequencies to pass? This next set I will use use the designated ones that come with JBL components. I still have an issue though. The tweets have a lower rms rating than the woofers. The tweets are rated for 60 rms and woofers are rated for 90 rms watts. Doesn't this suggest that the tweets will reach maximum volume before the woofers?? Wouldn't that increase the potential for tweeter to fail before woofer??

neo_styles
11-24-2013, 03:43 PM
Ok, so I recently blew my tweeters to my JBL P660c components. I blew my tweets but my woofers are fine. Now, this could possibly be my fault(wouldn't surprise me). I was using the factory internal crossovers from the Bose system that was previously in my truck. Maybe it was allowing some lower frequencies to pass? This next set I will use use the designated ones that come with JBL components. I still have an issue though. The tweets have a lower rms rating than the woofers. The tweets are rated for 60 rms and woofers are rated for 90 rms watts. Doesn't this suggest that the tweets will reach maximum volume before the woofers?? Wouldn't that increase the potential for tweeter to fail before woofer??

Because of differences in impedance between the woofer and tweeter. And, yes, use the passive crossovers that COME with the set next time. This is exactly why you do. Did you forget that's a 2-ohm set?

tat2bass
11-24-2013, 03:53 PM
No. A passive set does not split the power 50/50. Why it's always better to run active. So much more control of everything

Propel152
11-25-2013, 10:02 AM
Ok, I'm not sure what you mean by "differences in impedance between woofer and tweeter". They are both 2 ohm, correct??

trumpet
11-25-2013, 11:54 AM
You don't need the woofer and tweeter to receive the same amount of power. Passive crossovers not only divide the right frequencies, they make your radio or amplifier "see" a certain impedance even with 2 speakers in the circuit. The only impedance spec that matters for a passive component set is the system rating, not the woofer impedance and not the tweeter impedance. This is how what matters when you shop for an amplifier, the 2 ohm rating of P660C.

Propel152
11-25-2013, 02:39 PM
Ok, so the impedance combined. Which is the impedance the amp will recognize? I thought the woofer and tweeter had to both be 2 ohm? Are you saying the passive crossover determines what impedance is drawn from the amp and distributes accordingly? I know I just asked 3 different questions. lol I appreciate your help with this discussion!

T3mpest
12-07-2013, 07:26 PM
Yes. Realize that the power in a passage of music is split between octaves. You can hear between 20hz and 20,000hz. Each doubling of frequency is an octave so there are 11.5 octaves so in music (20,40,80,160,320,640,etc,etc) In the first 5 octaves, so approx half the scale you have 1/2 the power that exists in most music. So if you had a speaker that played 0-360 and another playing 360-2000hz on most music, the crossover would split power approx 50/50.. No realize most tweets cross around 3000hz. 3000hz -20,000hz is only 2.5 octaves, so around 15% of the power. So if your amp is set to play a song with 100 watts of power, only around 15 watts will need to go to the tweeter. Tweeters, truth be told are always weaker in powerhandling than speakers.

Generally when they rate them they rate what "program power" they can handle, so how much power is in the song, not in the part it plays, that's why you see 100 watt rated tweeters, a real 100 watts would pop them in an instant, but they don't need that much thankfully. If your just blowing your tweeters, odds are your clipping the amplifier, I'll explain why that happens next!

Clipping, has NOTHING to do with square waves or DC current or cones not moving or any other silly thing you MAY have heard, even on here lol. Clipping in a nutshell is when the amp tries to put out more power than it can, which produces both more power at the quieter points where the track could have been louder and higher order distortion at the points that were already maxed. The points that became louder are of no concern to the tweeter, as we already saw, most of it is filtered anyway. The issue is the "higher order distortion". Higher order means, higher octave. So if you distort a 300hz tone, part of that distortion is 600hz if it's second order distortion, the third order is 1200hz, etc. All this extra distortion is extra high frequency power that wasn't in the original track, so when your tweet tries to reproduce that, it's getting a real 30 watts of power now, 15 watts from the real track and 15 watts from all the extra crap the amp is adding to it! That fries a tweet rather quickly..

Since you are having problems hearing this distortion (some people don't notice it until they learn more and listen), you probably want to set yrou gains with a DMM for your components. There is a guide to that on this site in the amp section I do believe. I'd suggest a -3db tone and shoot for the RMS of your components or the rms of your amp, whichever is lower.