sr tweeter going into protect with 120w a side?

killerb

my tweeters are going into protect meaning the bulb is glowing and the tweeter is distorting. im running a carver m-4120 rated at 120w a channel. my head unit is a kenwood excelon with a 5v output. i checked the output with my oscope and get 5.6v of uncliped output. my amp sensitivity maxes out at 4v so i have gains set to minimum. i trimmed the fader to allow 3.8v of output and checked the output of the amp with a 0db 1khz signal and got a unclipped output at max volume, so i should get about 120w to each side. i even have the tweeter set to -1.5db. do you think im getting too much power? i know alot of guys are biamping with alot more power. i measured the tweeters and got about 2.9 ohms but the spec. sheet says they shoud be 3.5. could this be my problem? man i hate this. maybe the old carver is under rated.

killerb

i changed the tweeter setting to -3db and it only starts to glow at 35 on the volume, this is max volume. at 34 it doesnt glow at all. is it alright for the bulbs to glow sometimes? it acually sounds alot better with the tweeters set this way. i just thought they handled alot more power!

MacLeod

Good job on properly setting the gains, however a signal as clean and pure as the wind driven snow will still blow a speaker if its too much.

What kills a speaker is too much power, not distortion. That Carver amp is probably making a lot more than 120 watts as any high quality amp will always exceed its rated power so its very likely youve got too much juice going to the speakers by about 50 watts!

As far as the bulbs glowing, its ok if they glow a little. Thats what theyre there for. If youve got it set now to at max volume the bulbs glow just a little then it sounds like youve nailed it.

killerb

thanks for the advice. what do you think about the tweeter resistance being too low? could this be part of the problem with it drawing too much power? or just too much power?

killerb

excessive power is created by the harmonics of a clipped output which is really a form of a sqaure wave. but your right, it is the extra power that kills the driver. thanks alot, now i can listen in peace and not worry.

MacLeod

killerb wrote:

thanks for the advice. what do you think about the tweeter resistance being too low? could this be part of the problem with it drawing too much power? or just too much power?

It was just too much power.

excessive power is created by the harmonics of a clipped output which is really a form of a sqaure wave.

Totally agree, but most people think its the distortion that hurts the speaker and that if its a clean signal 500 watts wouldnt hurt a 100 watt speaker. I was just making sure you werent one of those people.

killerb

well everything seems to be fine now. it just seems the sr set just doesnt get very loud compared to my morel elate 6 set. i ran that with a u.s. amps tu-4360 at 75 x 4 with 75 watts to each driver with an active crossover. that morel set takes a ton of power with no sweat. the tweeters in the morel set handled 130w and the mids 180w. but i have to account for the power sucked up by those monster sr crossovers. well im getting older now anyway maybe my hearing is shot.:D

hrdhtdvr

MacLeod wrote:

What kills a speaker is too much power, not distortion. That Carver amp is probably making a lot more than 120 watts as any high quality amp will always exceed its rated power so its very likely youve got too much juice going to the speakers by about 50 watts!

Question, Why do they say that most blown speakers are caused by under powering then?? I understand that you cant say, put 300 watts into a 100 watt speaker, but I was under the impression that if you took the 100 watt speaker and put say, a 50 watt RMS/100 watt peak amp to them that they would blow because of the distortion that would be caused at higher volumes.

Am I making any sense?

Insert Carlos Mencia's "DDD" here.

audiobliss

This can be kinda fuzzy. I'll try and explain it, then Mac can step in, slap me, and say I got it all wrong.

You can think about it several ways, but let's just stick with thh idea that too much power is the only way you can blow a speaker. As Mac said, if you hook up a 500 watt amp to a 100 watt speaker, it doesn't matter how clean and pure the signal is, it'll blow the speaker.

Now, if you tatke a 50 watt amp and hook it up to a 150 watt sub, you're grossly underpowering the sub, which is another recipe for blowing a speaker - because of the distortion. The distortion itself doesn't kill the speaker...but it kinda does. When an amp clips, it begins to distort. The distorted signal, as I understand it, is four-sided, which quadruples the amp's output. So now you're pushing 200 watts into this 150 watt sub. It may handle it, it may not.

So, in other words, it's the excessive power created by distortion that kills the speaker, thus coming back to the idea that the only way to kill a speaker is overpowering it.

Though underpowering it is equally bad because it leads to distortion and then overpowering.

I get confused everytime I think about it.

killerb

underpowering will never kill a driver if you dont drive the amp into clipping. the problem is that some people will try to acheive a level of spl that cant be had with underpowering so they turn up the volume and drive the amp into clipping. your right this can quadruple the power to the driver thus killing it. sizing the amp to the job and proper gain setting will yeild great results. i cant really get what i want out of the system with my current set up. im going to tri-amp and go active crossover. the passive crossover sucks alot of power and i cant balance it. the old carver will have to go and im going to get some old us amps amps to go with the zapco. this will solve my power and gain problem. i have a old fosgate epx2 im going to dust of and put in. i always went tri-amp, but decided to try the passives and it is frustating. i want to be in control. i never blew a driver this way. how much power to the tweeters and mids with this set active? i was thinking 25-30 watts to the tweeters and 75-100 watts to the mids.

MacLeod

STFU Bliss! You got it all wrong!!!

There are only 3 things that will kill a speaker aside from manufacturer defects.

1) More heat builds up in the voice coil than it can dissipate which is caused by too much power.

2) The suspension is forced beyond its mechanical limits which is caused by too much power.

3) You stick a screwdriver thru the cone.

50 watts will NEVER EVER hurt a speaker that can handle 100 regardless how distorted it is.

The reason people associate distortion with blown speakers is when you push a speaker too hard it usually distorts pretty bad as its pushed to its suspensions limits. Like his tweeter. It was being sent a perfectly clean signal but it was being overdriven which was causing the speaker itself to distort. So its not the distortion thats killing the speaker, its just the noise it makes as its being overpowered.

My favorite analogy is if I shoot you with a gun, did the bullet kill you or did the bang?

The reason underpowering a speaker is bad is that if you take a 50 watt amp and power a 100 watt speaker well thats not really that much power and its much more likely youll turn the volume up to get the extra power but in doing so youll push the amp into clipping which sends out more than double the amps rated power and BOOM! Your 50 watt amp is not sending out over 100 to your 100 speaker so it blow.

hrdhtdvr

Thanks for the info.

So how do you figure what amp for what speakers?

Say the MM2104 300 watts RMS and 600 Peak.

What would you consider as the weakest and what would you consider as the strongest amp for this? Is there a set % of RMS or other formula to use?

Thanks again.

exalted512

get it as close to 300w as possible. More is better, because then you can back down the gain a little, giving more head room for sudden bursts and also extending the life of your speakers.
-Cody

killerb

well, i just got a new audiocontrol dqxs and will get rid of the passive crossovers. this should be fun. 24db crossovers and 30 band 1/3 octave eq plus tons of other features. im going to install it next week when my cables come in.

MacLeod

Good for you! I want a good EQ so bad it hurts.

Hopefully one day Ill hold up enough liquor stores that I can get an Alpine 701.

killerb

well i got the dqxs in last night and it sounds excellent!! i set it up with a 0 db signal, but im going to redo it using a -5db signal. i read that most cd's are recorded from -14db to -3db depending on the year made. i also just got a phonic paa3 rta to tune the car. this little hand held rta is cool. so guess what ill be doing this weekend?:D

Airplay355

Mac you're pretty wrong actually. Read the manual for the Polk speakers, even Polk says trying to push a wimpy amp too far will result in damage to your speaker. It's not noise or the speaker itself distorting, it's the speaker trying to produce a clipped sin wave it's being sent. The sin wav is clipped because the amp does not have enough power to complete the wav at the volume you're asking it to, so it goes as high as it can, and the top of thw wav is the squared off resulting in distortion.

It doesn't have to do with making your 50 watt amp push too much into your speakers thus overpowering them.

You're right about too much power blowing speakers. But you can damage them by underpowering them and turning the gain up too high.

killerb

a speaker can play a square wave all day long as long as the thermal limits are not exceeded. they dont know if you are playing a square wave or a perfect sine wave, they do notice heat. the extra heat comes from the odd order harmonics of a clipped amp output. each harmonic adds power to the fundamental freq. which is your perfect sine wave. with the first odd harmonic which is 3rd. it adds 1/3 the power. so if you had 100 watts you get an added 33.3 watts from the very first one. then 1/5, 1/7, 1/9 and so on up to 1/15th. the added power can be huge and that kills a lot of speakers. with mild clipping you may only introduce the 3rd harmonic, but 1/3 more power is a lot of power. set the gains the right way and stay safe. remember the t.h.d. rating on your amps, total HARMONIC distortion. pushing your amp into more distortion will yeild higher wattage numbers. thats why we look for good power into low t.h.d. numbers.

Airplay355

Ok...

MacLeod

Airplay355 wrote:

Mac you're pretty wrong actually. Read the manual for the Polk speakers, even Polk says trying to push a wimpy amp too far will result in damage to your speaker. It's not noise or the speaker itself distorting, it's the speaker trying to produce a clipped sin wave it's being sent. The sin wav is clipped because the amp does not have enough power to complete the wav at the volume you're asking it to, so it goes as high as it can, and the top of thw wav is the squared off resulting in distortion.

It doesn't have to do with making your 50 watt amp push too much into your speakers thus overpowering them.

Right, push an amp into clipping and youre much more likely of blowing a speaker, however it has NOTHING to do with the shape of the wave and EVERYTHING to do with the amount of power being sent to the speaker.

At the point of clipping, an amp will make a ton more power than it does in normal operation and it will be limited only by input voltage. So that 50 watt amp will make well over 100 clipped and if you have that amp hook up to a 75 watt speaker itll fry it. However, you hook it up to a speaker thatll handle 200 watts and itll play that clipped signal all day long.....and twice on Sunday.

You're right about too much power blowing speakers. But you can damage them by underpowering them and turning the gain up too high.

Youre 100% right because by turning the gain up too high, youre pretty much guaranteed of driving your amp into clipping and thus blowing your speakers.

Underpowering a speaker will NEVER hurt it.

A speaker doesnt care what the shape of the wave is its playing. As long as its within its thermal limits to where it can disipate the heat out of the voice coil faster than it builds up, or as long as its not pushing the speakers suspension beyond its limits, the speaker will not be hurt. And the only thing that can cause too much heat and/or too much extension is too much power.

Airplay355

Then I read what you typed wrong and though you were saying something different lol. Sorry.

MacLeod

Dont let it happen again!