8 speakers just blew out?!

[CRAIGTHEMAN]

this last winter i put in a new stereo system in my boat and had everything working fine and dandy untill yesterday..well first of all i have 2 clarion amps running 8 polk momo speakers....had the stereo playing yeasterday when all of a sudden it sounded like crap...so today i looked at it and only the woofer part or the speaker was playing on all 8 of them...check the tweeter and there is nothing coming out of them even when i wire them stright and not threw the crossover...so how did i blow all those out or do u think sumthing else is wrong????

[TX.X-30 fan]

If the amp clips from overheating I have lost the highs until it cools, but I have JL amps.

[CRAIGTHEMAN]

i let cool overnite and still no highs in the tweeters anyone else have any ideas???

[TX.X-30 fan]

JimN or master baker will be along and know whats wrong, or a half dozen others.

[D3skier]

did you check your fuses on the amps?

[cbryan70]

Did the amp click over to only i beleive low pass mode? Just hoping for an easy solution for ya. Did you try adjusting the amps highs and lows?

[CRAIGTHEMAN]

checked all fuses were good and everything is on high pass..im pretty sure i blew out all the tweaters but just trying to find out why cuz i really don't wqnt this to happen again

[TX.X-30 fan]

Has to be the amp, no way you blew 8 tweaters.

[cbryan70]

take a speaker out and hook it up to your house radio...

[skihard111]

Possible thermal overload switch kicked in. A friends kid cranked my system all the way up, and it kicked off to only turn on with the same results. Speakers were not happy but they weren't blown either. Look to see if the power light is blinking instead of solid. I think this indicates the thermal protection. Disconnect, check fuses etc. All speakers didn't just "blow"....doubt that. After reconnecting my led indicators went back to solid blue again.

[TX.X-30 fan]

Possible thermal overload switch kicked in. A friends kid cranked my system all the way up, and it kicked off to only turn on with the same results. Speakers were not happy but they weren't blown either. Look to see if the power light is blinking instead of solid. I think this indicates the thermal protection. Disconnect, check fuses etc. All speakers didn't just "blow"....doubt that. After reconnecting my led indicators went back to solid blue again.




Got my money on this.

[JimN]

"Has to be the amp, no way you blew 8 tweaters."

WRONGO! When an amp distorts badly enough, it clips the top of the waveform off. Draw a sine wave and then draw a line across, at some arbitrary point above the 0 line. Those short, straight lines are DC. No real difference between that and continuous DC, other than the brief gaps. DC heats the voice coil and if it gets too hot, it opens. It can also melt the glue and enamel that coats the winding, deforming and freezing it in place. Either way, they're all toast.

This could have happened in many ways. #1 is improperly set amp and head unit levels. #2 is inadequate power supply. #3 is overtaxing the charging system.#4 is loose connections and/or incorrectly set amplifier switch positions/configuration.

Thermal overload usually go on after they cool down. If the tweeters don't make any sound when they're connected directly to an amp, they're dead and unless they have replaceable diaphragms, there's no bringing them back. Fuses in crossovers are a waste. They do absolutely nothing to eliminate the effect of clipping distortion, just excessive current. There's no way am amp or crossover's thermal protection is still tripped after sitting overnight, unless it needs to be reset manually.

One of the easiest ways to limit current to a speaker, especially tweeters is by adding a dome light in series, but just by making that change, the crossover's -3dB point won't be where it was in the original design.

The best way to prevent this is by setting the levels correctly and not going WOT with the volume control. This won't be caused by an amp that passes DC, it won't happen with clean signal at low levels and it's not 8 defective tweeters. This happened because the input sensitivity pots were set too high and the volume was cranked up, possibly with the bass and treble controls set high on the head unit.

[JimN]

CRAIGTHEMAN- What gauge is your power cable, how are the terminals attached, how long is the power/ground cable and how are the amps connected? Are you using a distribution block? You don't need a fused one. What are you using to protect the power cable, at the battery? What is the total rating of the amplifiers' fuses? Where did you ground the amps? How are the input sensitivity controls set? Maxed out or did you actually listen for the point where the head unit and amps distort?

[CRAIGTHEMAN]

i pulled the crossovers apart and in everyone had that capasotors all blew apart..what the heck could of done that all at once??? jimn im using 4 gauge with a block going out to two 4gauges that go out to both of the amps...the power cables are only 5 to 6t feet long and go to main fuse that is 100amps that equal the amount that is build into the amps...the amps are directly grounded into the battery..i only have the gain up a little more that half way...have any clue jim on what could of blew all the crossovers out???

[JimN]

How much power are the speakers and crossovers rated for? Caps blow because of too much voltage, in most cases and crossover caps are generally rated for 25V.

You said you connected the tweets directly to the amp and still had no sound, right?

Do a search for other audio threads and look for one where I described setting the sensitivity controls. "a little more than halfway" will put you well into clipping if the head unit is turned up much. Add more clipping if the bass/treble controls and loudness are up.The input controls may have a voltage at the upper limit and if that shows 2V, you need to do a complete setup before using it again. That may or may not be described in the manual, but who reads manuals anyway, right?

You need to understand that amplifiers work by creating a voltage differential. For a specified voltage input, it may be anywhere from 1:2 (lower power amps) to 1:20 (or more). This means that if you present 1 V to the input, you'll get 2 V out. The limiting factors are: which output devices are used and power supply voltage created in the amp. The charging system is limited to ~14VDC and you can't go below 0VDC. Using Ohms's Law to determine voltage, P=E²/R and if the amp is capable of 14V of output, your power is P=14²/4, or 49W, if the speakers have a resistance of 4 Ohms. Speakers never have a stable resistance and are rated as having "impedance". There are a few different kinds of impedance and to keep it from getting too detailed, I'll just use "impedance" in general for the discussion. No doubt, your amp is rated at higher output than 49W, so the only way for it to be able to exceed the power supply voltage going in is by creating higher voltage internally. You can't use a transformer to increase DC voltage, so it needs to be converted to AC voltage, run through a transformer, rectified back to DC and filtered to minimize any voltage "ripple". Now, your amp may have a power supply volltage of more than 100VDC, which is right in the ballpark for MOS FETs and some other really good output devices.

What happens next is still within the realm of that differential I mentioned before. If your amp is rated at 100W into 4 Ohms, it needs to output 20V into that load.That's pretty close to the 25V rating of the caps (they're usually rated at 25V, 35V, 50V, 100V and higher if they're electrolytic). If your amp is capable of more than 100W, the voltage goes even higher and if your input sensitivity is too high, it goes still higher. 200W into 4 Ohms is 28.3V, which IS probably more than the caps are rated. If Polk designed the crossovers correctly, they built in a margin for peak power but if your amp is rated higher than the speakers, I doubt they'll cover this under warranty. Then again, they may. Fortunately, caps aren't always expensive and they're easy enough to install if you can solder. If you can't, any good stereo service or installation shop can do it for you. The parts values need to be the same in order for them to work as designed.

[tbd01]

jimn, you are probably the smartest person Ive never met, very nice diagnosis

[JimN]

"you are probably the smartest person Ive never met,"

Pfffft! This is just some of the stuff I have picked up over the years by talking to friends who actually studied electronics.

[BriEOD]

Being humble again Jim? You have probably forgotten more than most of us know.

[TX.X-30 fan]

"you are probably the smartest person Ive never met,"

Pfffft! This is just some of the stuff I have picked up over the years by talking to friends who actually studied electronics.




I thought I was? 35663

[CRAIGTHEMAN]

thanks alot jim for all the info..when i get my new speakers i will pay more attention to the finer detail of tuning it in..thanks alot again

[CRAIGTHEMAN]

also yes jim the crossovers were blowen and also the tweaters themself were too

[TX.X-30 fan]

So what is the best guess here? wiring, Low voltage from alt.. any guesses?

[JimN]

Next step is finding the point where the head unit distorts and not going past that on the volume control and setting the input sensitivity on the amps so they won't distort. If this is done and the amps aren't too powerful for the speakers, it shouldn't launch any more tweeters and caps.

The point where the head unit doesn't distort should be found with the loudest CD you have. This is so you'll push the output to its maximum and if it's done with a quiet CD, once a louder one is played, the whole problem shows up again. They do vary greatly and if I need to do this I would use Climax Blues Band's FM Live or Leslie West's Guitarded. I don't think I have ever heard louder ones. First step, turn the input controls on the amps down and play the CD, listening for distortion on the loudest parts, but not distorted recorded sounds. You want to be playing music with clean sounding instruments, not heavily distorted guitars. If you hear it break up on the kick drum or synthesizers in the loud parts, back it off until it doesn't and make a note of that point on the volume control. Use several examples for this and use them for setting the head unit and amps. Next, play the same tracks and, with the head unit at the highest clean setting, gradually turn the input sensitivity control of one amp up to the point where it distorts. This is best done while wearing ear plugs because it's hard to hear when the distortion starts at high volume. Once this point is found using all of the tracks (one tune isn't a very representative sample), mark the position accurately on the amp (tape and Sharpie if you don't want to permanently mark the amp), turn that one down and repeat with the other amp, marking the position. Now, turn the head unit down and turn the input controls up to the marks on the amps and listen to it. It should sound very clean and will still be loud. Loud and distorted just sounds bad, especially from a distance. Loud is bad enough for ears but loud and distorted is even worse for them and if you have ringing all the time when there's little other noise, the damage may be permanent.

The alternator was probably putting out whatever it's supposed to, but I would measure the voltage at the amps at the highest volume level. If that's low, the amps will never put out their rated power and if they do, it won't be clean power. If the voltage goes back to normal when hte system is turned down/off, a high output alternator is needed and possibly an additional battery, not a stiffening cap. Stiffening caps are OK for peaks but for sustained high power use, a battery is better. A battery stores much more energy than a cap, although a 1 Farad cap does store a lot.

[O2BESOHUGE]

Maybe The Crossovers Were Bumped And All The Highs Were Taken Out Of The Speakers....may Be Just A Flip Of A Switch

Ive DonE That By Accident On Rockford Amps Before

[CRAIGTHEMAN]

thanks again jim for the info...i do have a high output alt and a dual battery setup if that means anything????

[brucemac]

wow, i'm really suprised this happened. i had those mmc650's on my last boat and they worked flawless for 2 years. i was only pushing like 50W RMS with a 6-channel JL though, so nothing too fancy. they saw plenty of high DB and high heat too.

hey someone get that jim guy on jeopardy already! ;)

[JimN]

All of that means the supply voltage is probably good but amps still put out more power at higher voltage input, which means that when you're idling, turn it down of you want it to stay clean, or set the levels at higher RPM and if it distorts at idle, turn the sensitivity controls down so it doesn't. Once all of that is done, it should be pretty trouble-free for a long time unless someone who doesn't know about the maximum volume setting cranks it higher which to me, is like someone driving your car and mashing their foot to the floor. Anyone who does that to my car/equipment doesn't get a second chance to drive/use what I have.

I don't know how many hundreds of systems I installed that never came back with problems and some of the best sounding ones were pretty low power.

[CRAIGTHEMAN]

alright guys i lied to you..i finaly just pulled everything apart and the is the verdict..i have one speaker with a blowen tweater and the rest are good but all the crossovers are fried...3 of them look good but just didnt work and than 5 of them have the capsators just blown to pieces..also i noticed that the porclen resistors were getting really hot and distored the plastic a little bit..do you think jim that i still had to much voltage going to them????

[Lennyp04]

OK quick threadjack.

So I'm reading this and thinking I shouldn't hook the amp that we got up to our speakers in fear of a catostrophic malfunction and a nice bill to replace all of it. The amp is a 2000 Watt Pyle 6 channel. Anybody know?

Thanks and sorry!

[JimN]

Yup. Too much voltage and current through the resistors. Any resistor will get hot. When you have excessive current, they get very hot. Caps go because of voltage but when you have too much voltage across a given resistance, the current will also be excessive.

Again, what is the power rating on the speaker system? Power is a function of voltage, load and current. There's no way to argue with physics and win.

[JimN]

Lenny- you can connect everything, just set the amp's up so they don't exceed the rating of the speakers, or make sure you can't/don't go past a certain point with the head unit.

[Lennyp04]

Very good Jim. Thanks for the heads up!!!!!

[CRAIGTHEMAN]

awsome thanks again jim for all the info...maybe this time i can make it last a little more than a few hours of play time