Just clearing a few "myths"

[MikeofTulsa Moderator]

very interesting indeed....always enjoy a good discussion....

 

[jlaine 10+ year member]

Originally posted by sforget I have been working with car audio for over ten years, and buy every issue of Car audio & electronics. These guys will tell you the same thing. basically to clear up what I meant. Underpowering speakers causes more distortion. Distortion causes the speaker to act erratically instead of following the wave of power that it is given. this erratic performance causes damage to the spider, and sometimes to the voice coil.

Do you realize the pathetically small margin of harmonic distortion that is given out? And on the same hand, realize that the subwoofers natural rolloff will just take that energy and laugh at it? It is a few fractions of a watt usually...

Do spiders, suspensions, or speakers in general have feelings? The speaker is following the wave of power that it is given, it is the wave that is the problem.

Underpowering? Where did this completely bogus term come from?

Distortion is not underpowering. Distortion is from US, the end user, OVERDRIVING our amplifiers. Distortion is not causing the speaker to act erratically, it's doing exactly as the amplifier is telling it to...

 

[Wonderbread 5,000+ posts]

d@mn right there josh, speakers only do waht they are told to do...

distortion and everything allong taht line comes from the amplifier and teh user not knowing the limits of the amplifier...

 

[RangerMan Premium Member]

Originally posted by Mark_ab  

You said it. I hope the heavyweights come out (zane, Loyd, Josh - ramos already did)! I love cognative dissonance, you almost feel embarassed for him...almost.

Yeah I choose to stay out of this one...I knew Mr. Laine wold come out with a big right hook...I caught sforget's mistake, and I knew it would be interesting, but I choose to shut my mouth, I am trying to stop arguing so much on the forum...as soon as he said underpowering causes distortion, he was screwed...

 

[chris229 10+ year member]

Originally posted by ramos  

I have been involved in car audio for a couple of decades myself //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Although I don't buy every issue of any magazine.

I don't care what anybody will tell me. I know what I have seen with my own two eyes. Underpowering speakers does no harm. Underpowering does not cause any extra distortion. The user cranking the volume way up to compensate for the lack of power causes more distortion. Which brings us back to underpowering does nothing. Speakers are damaged by exceeding the thermal limits of the voice coil and motor assembly. Or by some yahoo poking a screwdriver or some other sharp object through the cone, dust cap, or surround. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I agree. PLUS too much power for a given box size. This causes mechanical damage

 

[ramos 5,000+ posts]

Originally posted by chris229 I agree. PLUS too much power for a given box size. This causes mechanical damage

True left that out, my bad //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[more_spl 10+ year member]

how exactly do you know if to much power for a box? my box chambers are gonna be about .7Ft^3 after driver is in it.. how do i know if it's causing harm to the driver?

 

[vasyachkin 10+ year member]

about this underpowering stuff - here is the WHY part so you can judge for yourself.

if you have a system that is at least 2-way its tweeter will blow as soon as you drive the amp into distortion (clipping). this happens because distortion in itself is high frequcy signal which goes straight to the tweeter and fries it in seconds. you can fry a 100 watt tweeter on a 20 watt amp if you drive this amp into distortion. on the other hand if you have a 200 watt amp and play it at 100 watts it will not be distorting yet, and the tweeter will survive the 100 watts its rated for, while on a 20 watt amp the tweeter would be blown on just 25 watts or so (the extra 5 watts being distortion killing the tweeter).

on the other hand, if were talking a subwoofer, or otherwise a sytem that is only one-way, with driver connected directly to amp - there is no danger from extra distortion (no tweeter to kill) and underpowered amp will be just as safe as one of proper size.

this is one reason why recording studio monitors often use dedicated amplifiers JUST FOR THE TWEETER because that allows to disconnect the tweeter from the amp powering the woofer, so that when woofer amp distorts the tweeter does not see its distortion and does not die.

 

[chris229 10+ year member]

Originally posted by vasyachkin about this underpowering stuff - here is the WHY part so you can judge for yourself.

 

if you have a system that is at least 2-way its tweeter will blow as soon as you drive the amp into distortion (clipping). this happens because distortion in itself is high frequcy signal which goes straight to the tweeter and fries it in seconds. you can fry a 100 watt tweeter on a 20 watt amp if you drive this amp into distortion. on the other hand if you have a 200 watt amp and play it at 100 watts it will not be distorting yet, and the tweeter will survive the 100 watts its rated for, while on a 20 watt amp the tweeter would be blown on just 25 watts

this isn't true. distortion doesn't kill ANY speakers it the power that kill them. YES, tweeter get the extra power when clipping hard into distortion. This is because of the harmonics of the distortion producing more midrange and tweeter signals. It would take a 50watt or more amp to blow a tweeter of 100watts. speakers do not blow because of distortion. it's from passing the thermal limits. Clipping isn't bad for amps or speakers anyway. It the hard clipping that causes damage

 

[vasyachkin 10+ year member]

you ASSUMED that a tweeter normally sees a considerable portion of system power - this is not the case. a tweeter crossed at about 4khz normally sees about FIVE PERCENT of full-range power. that is if you put 100 watt clean power into the system the tweeter will get 5 watts average. this tweeter if rated 100watts can in reality only handle 5 watts, cuz that is all it needs to handle. now you clip a 20 watt amp into it hard and it now sees more, lets say 10 watts - it dies.

you are not believing me, and the reason is that a tweeter sounds just as loud as woofer, but this is a psychoacoustic effects. most music energy is in fact in midbass and bass, but it APPEARS that energy is more or less evenly spread out.

just to be politically correct, short-term transients in treble do reach high levels, perhaps 10-20% of total power, but those are too short to overheat the tweeter voice coil usually.

 

[Plater 10+ year member]

Wow this is fun

I think we are all getting caught up in wording issues.

But any ways.

How the F#*& do you under power a speaker what the F%#! happens when you turn the volume on your deck to 1 how much F%#!ing power is coming out of the amp .001Watts or so how come my speakers don't blow!!!!!!!!!!!!!!!!

Woo sorry i kind of got a little caught up in what i was doing. Sorry about the lang.

Running 5V (AC) into an amp. and setting the gain to full and watching a lovely sine wave turn into to lovely square wave on the output can have "negative" results as far a the amp and speakers are concerned. There is nothing like listen to fully distorted bass its awesome!!! Oh wait it sounds like S% but many people do it. In general these are the people that post stuff like i hooked up my subs and they both blew up i was only runnig 100W RMS amp into my 1000W PMPO (peak music power output) sub i got a radio shack

(no disrespect radio shack) you just sell crappy stuff.

Oh and the marketing guy who came up with PMPO what a genuis give the guy a prize and the prize is one free shooting, i'll stop there. I won't even get started on that one.

Back to the post about inductive noise between cables have you ever started your car and put a scope on the battery terminals. It is a prefect 12 supply right, wrong it is the farthest thing from it. Having or not having noise in your speakers/amps. comes down to grounding and how well the input stage of the amplifier is at rejecting noise (power supply rejection ratio) oh and so i don't get attacked about input noise there is common mode rejection ratio (CMRR) on the input stage. I run $1.50 RCA cables to my amps the cheap amp hums a little the good one doesn't.

Well thanks for listening sorry if i affended anyone if i did send all remarks to someone else.

If there is anything in this that you don't agree with feel free to attack me i don't know everything by i am trying hard. LOL

 

[Plater 10+ year member]

I missed this last page it gets even better

I will have to go read the dictionary and figures out all those big terms then hit my acoustics books on power vs frequency band and response to how a 100w tweeter blows at 10W etc.

 

[chris229 10+ year member]

Originally posted by vasyachkin that is if you put 100 watt clean power into the system the tweeter will get 5 watts average. this tweeter if rated 100watts can in reality only handle 5 watts,

this is were your lost--- if a tweeter is rated for 100w then it is rated for 100w an 5w will NEVER BLOW A 100w tweeter. so are you talking about a 5w or a 100w tweeter .... yes 10W will blow a 5W tweeter. Unless the RATING are correct we can even begin to debate this.. you idea states that a 100W tweeter is really a 5W one... well call it a 5W tweeter then NOT a 100W.. then you can see 10W will kill it.

 

[chris229 10+ year member]

Originally posted by Plater
Back to the post about inductive noise between cables have you ever started your car and put a scope on the battery terminals. It is a prefect 12 supply right, wrong it is the farthest thing from it. Having or not having noise in your speakers/amps. comes down to grounding and how well the input stage of the amplifier is at rejecting noise (power supply rejection ratio) oh and so i don't get attacked about input noise there is common mode rejection ratio (CMRR) on the input stage. I run $1.50 RCA cables to my amps the cheap amp hums a little the good one doesn't.

correct with very good power supply isolation on all proceesors and amps and a HU with LOW source impedance. The only problem that can occur is grounding the HU in a high current path which is VERY bad as the signal is sourced to the ground AND noise induction directly into the wires. If UTP doesn't fix the noise then a balanced system will

 

[vasyachkin 10+ year member]

chris, i dare you to take a 100watt rated tweeter, a 30watt rms amp, use a pure sinewave tone (anywhere between 5khz and 20khz) and deliver it into the tweeter on maximum gain. the tweeter will not last more than one minute.

i did not make the 5% number up, i cant find that study now but it was all well documented.