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joel321

join:2013-04-13
USA

Install fuse to speaker question.

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Hello guys I'm having issues with my car audio car system blowing speakers. This is my 4th speaker that blows.

I'm trying to narrow it down but I believe I have some ground issues somewhere.

From what I have seen the amp gets really hot and I start to smell this sweet smell (from electronic components over heating) and then pop...the speaker blows.

I know is not the amplifier because I already used another brand new one.

Any woo! I would like to seek assistance here in installing a fuse between the amp and the speaker. Like I said, this blowing up speakers is getting expensive, I would rather blow a one dollar fuse.

The specs of the sub-woofer I'm using is on the pictures and the amplifier I'm using is a JL 500 watts RMS @ 2ohms.

Thanks in advance for your assistance.

joel321

join:2013-04-13
USA
I'm looking to do something like this...




leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
kudos:10
Reviews:
·SONIC.NET
To protect the speaker and still get the full audio output power you would need a 15A fuse (500W into a 2Ohm load is about 16A but the nearest common fuse rating is 15A).

The fuse itself has some resistance and therefore will slightly reduce the output power. If you are using a fast acting fuse there may be false trips while a slow blow fuse may not act fast enough to prevent speaker damage.

Instead of a current based fuse, it may be better to attach a thermal fuse as close as possible to the speaker coil.
--
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iknow_t

join:2012-05-03
reply to joel321
my god!! how big is the car that you need a $699 speaker??. anyway, are you driving it with 2 amplifiers? (1000W total) that looks to be the problem. that speaker should handle 500W all day and night no problem.. but yeah, as has been said a 15 amp per channel fuse will do it..

joel321

join:2013-04-13
USA
reply to joel321
quote:
Instead of a current based fuse, it may be better to attach a thermal fuse as close as possible to the speaker coil.
That is a great idea. I actually have some left over ones from a previous project of mine.

What rating should work best?

In my drawer I have 149C 15A ones. I have difference sizes at work though.

Thanks.

quote:
are you driving it with 2 amplifiers? (1000W total) that looks to be the problem. that speaker should handle 500W all day and night no problem.. but yeah, as has been said a 15 amp per channel fuse will do it..
I'm driving it with just 500 watts amp. This leads me to believe that I have some ground issues somewhere.

Thanks.

joel321

join:2013-04-13
USA
reply to joel321
I have another question guys. Is this possible for todays high rated amplifiers and speakers?

quote:
9 - How to Completely Prevent Speaker Failures
Some famous US speaker makers (e.g. Bose and JBL) have discovered how to prevent speaker failures and dramatically improve the input power ratings at the same time. Impossible you say? Actually, it is dead easy.
All you need to do is fit a low voltage halogen light bulb in series with your woofer - chosen so it has almost no effect at the 1 watt level where efficiency figures (dB per watt) are always measured and quoted but lights up brightly and limits current flow when the power input is enough to threaten the woofer. This works because the resistance of the filament typically varies by around 1:10 from cold for full brightness, so when hot, the series resistance is high enough to protect the speaker.
If higher than rated system power is ever applied, the bulb simply burns out rather than the woofer!!!
Using this approach, a 4 inch 20 watt, 2 ohm wide range driver becomes rated at 80 watts in the Bose 101.
Similarly, a 6.5 inch, 30 watt, 4 ohm woofer accepts 160 watts of "nominal" input in the JBL Control 5. [3]
Pure genius or a dishonest but cunning dodge? Seems all is fair in a game where reality has been rendered meaningless.
»sound.westhost.com/articles/spea···.html#s3


leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
kudos:10
Reviews:
·SONIC.NET
Yes. An incandescent bulb acts like a PTC (a resistor with positive temperature coefficient). As the quoted text correctly states, it has a low resistance at low temperatures but that resistance significantly increases with temperature.
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ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
reply to joel321
Yep the good old light bulb trick. Proven method that works rather well, lights up instead of blowing a fuse.

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel

1 recommendation

reply to joel321
There could be a number of things going on.

First off, make sure you're not driving the amplifier into clipping. When an amplifier is clipping it will put more power into the subwoofer than its rating, and can definitely be the cause of burning out voice coils. Could also be why the amplifier is running hot.

Secondly, make sure the subwoofer is in a box/enclosure that is suitable for it. Too small or too big a box can definitely cause problems.

Please provide a specific model number for you amplifier, and explain how you've wired it up with respect to connecting the speaker(s) to it.

Also check how you've got your crossover and/or low/high-pass filters set up. Make sure you're only sending the subwoofer frequencies that it is able to reproduce.

iknow_t

join:2012-05-03
reply to joel321
thinking about this for a bit, it seems you need to crank the volume possibly all the way, so that you can hear the music properly, it's possible you need a much beefier setup. maybe around 1500 watts. (speaker and amp) that way, full volume will sound twice as loud, and half volume will sound louder than it does now, but will not burn out. you might not need to run it full volume anymore.


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
·Frontier Communi..
reply to joel321
said by joel321:

From what I have seen the amp gets really hot and I start to smell this sweet smell (from electronic components over heating) and then pop...the speaker blows.

You mean the voice coil burns up? Or some other failure, perchance?
--
.sig


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 recommendation

Looking at the pictures, the failure at least in those photos would seem to be a mechanical failure, not an over current or power.

Keep in mind this depends on which came first the heat or insulation failure. What I'm seeing is a failure at the flex point in the cable attaching to the speaker, causing shorting and arching. For a better analysis looking at some speakers during heavy use with a infrared thermometer might give some good insight.

As for the speaker pictured if the failure is strictly at that point it can likely be repaired.

joel321

join:2013-04-13
USA
reply to joel321
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quote:
First off, make sure you're not driving the amplifier into clipping. When an amplifier is clipping it will put more power into the subwoofer than its rating, and can definitely be the cause of burning out voice coils. Could also be why the amplifier is running hot.
I played the unit yesterday at volume level 48 for about two hours and was monitoring the amp and speaker temperature. The speaker never got hot and the amp just barely got warm.

I will have to do more testing though.

quote:
Secondly, make sure the subwoofer is in a box/enclosure that is suitable for it. Too small or too big a box can definitely cause problems.
The box is build from the JL recommendations.

quote:
Please provide a specific model number for you amplifier, and explain how you've wired it up with respect to connecting the speaker(s) to it.
JL 500/1 slash. »www.jlaudio.com/500-1v2-car-audi···rs-98080

I have it connected to the speakers as a 2ohms load (4ohm coils in parallel).

The speaker wire is 11 gauge.

quote:
Also check how you've got your crossover and/or low/high-pass filters set up. Make sure you're only sending the subwoofer frequencies that it is able to reproduce.
The filter is set at 24dB down to 40Hz set for low pass.

From looking at the speaker specs and box specs, the speaker and box can handle 40Hz.

I still believe I have a ground issue somewhere. I believe that when I drive over bumps, the ground wire loosens and causes excess amp draws and it over heats in a matter of minutes.

Thanks for your input though.

quote:
thinking about this for a bit, it seems you need to crank the volume possibly all the way, so that you can hear the music properly, it's possible you need a much beefier setup.
per crutchfield recommendations to set the sensitivity. I need to lower all the bass, tremble, gain, etc on the head unit and amp. Raise the volume all the way up until I hear distortion, then lower it a few notches and that would be my max. then set the input sensitivity on the max volume.

Here's what I believe is going on so far now.

a- input sensitivity to high.

b- ground wire problems somewhere.

quote:
You mean the voice coil burns up? Or some other failure, perchance?
The amp has thermal protection. It just shuts off when it over heats but burns the coils. On one occasion there was smoke coming from a speaker and I took it out and it was so hot you could literally cook and egg on it. I know cus I touched it by accident when I pulled out the speaker to see if there was fire and the magnet was so hot that it cooked my skin.

quote:
Looking at the pictures, the failure at least in those photos would seem to be a mechanical failure, not an over current or power.

Keep in mind this depends on which came first the heat or insulation failure. What I'm seeing is a failure at the flex point in the cable attaching to the speaker, causing shorting and arching. For a better analysis looking at some speakers during heavy use with a infrared thermometer might give some good insight.

As for the speaker pictured if the failure is strictly at that point it can likely be repaired.
I suspect and over current because I have seen this before in other areas. Here are a few examples.

1- A long time ago I had a car system in my car. Came home with music blasting turned of the car and went inside. The next day, got in my car to go to work and was welcomed with the blasting music because I didn't lower it the previous day. That sudden over current burnt the cable coming from the alternator right at the connection.

2- I work in air conditioning units for a living. I have seen many over current cables exploding like this. This has happened at the connections coming out from the compressor. Older units don't have timer relays. So when joe blow turns the heater on my mistake and then switches to cool in an instant, there is excessive current draw that cables burn and explode at certain locations.

I also pushed the cone of the woofer all the way in with my hand several times and there was enough slack that that part of the flex wire was not even moving.

So from experience I can conclude that there is over current going on for some reason in my system.

Yes I was able to bring back to life the speaker I added the 15amp fuses suggested by leibold. I tried to add thermal fuses but that added a lot of resistance.

Thanks for the help everyone.


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
Reviews:
·TekSavvy DSL
said by joel321:

I still believe I have a ground issue somewhere. I believe that when I drive over bumps, the ground wire loosens and causes excess amp draws and it over heats in a matter of minutes.

This is utter nonsense.
--

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
reply to joel321
A bad ground usually causes reduced amplifier output power, distortion, or in extreme cases the amplifier to shut off into protection.

A bad ground won't fry voice coils. Not unless there's something very strange about the design of the amplifier.

joel321

join:2013-04-13
USA

1 edit
reply to joel321
Yeah I've been reading about JL amplifiers and learning about the system as I go.

For example I have the slash 500/1 and the XD600/1.

Two difference characteristics from them are...

the XD600/1 does not shut down completely if it over heats. It just lowers it's output somewhat.

The XD600/1 is half the size from the slash.

The XD600/1 heats up the speakers really bad, while the slash500/1 does not.

Maybe it may not be a ground issue but that is what I have read from my searching. Maybe these amplifiers are very sensitive to input gain.

Another interesting thing I have learned from JL amps is that they can output more power than their RMS rating ...here is an example....

»www.talkaudio.co.uk/ipb/index.ph···testing/

this caught my eye...from that link.

"Micb I'm pretty sure all the slash amps are underrated, I've seen a 500/1 benched at 2ohm doing over 700 watt even though it says itl do 500 at 1.5 - 4

That to me is underrated.

And I also remember Steve atega watt posting 750/1's were doing nearly 900.

Anyway, from the tests the guy has done for us shows some serious power from such a tiny amp."


so maybe for some reason I am pulling more amps than the RMS.

Here it says that high power damages speakers. But if I have a 500RMS/600RMS amp how can I damage a 750RMS speaker?

»www.bcae1.com/2ltlpwr.htm
»www.bcae1.com/speaker.htm

you live and you learn I guess.

Can't find the link where I read about ground issues causing amp to over heat...i read this buy doing a quick gloogle

“If an amplifier loses its negative line it will try to feed high power negative through the RCA's
this could damage your radio head unit crossover equalizer etc.”

thanks anyways.


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Is that a DC or an AC coupled amp?
--
.sig

joel321

join:2013-04-13
USA
reply to joel321
^i would not know. I can take them apart (which i like to do) and post high resolution pictures. How can you tell which is which?


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
·Frontier Communi..
An AC coupled amp should have a big capacitor at the output, thereby preventing DC going out to the speakers.

A DC coupled amp doesn't have a cap, and if it malfunctions in certain ways, some DC can go to the speakers.

The crossover for midranges and tweeters normally contain a series cap, so they're immune, but woofers can be damaged by it.
--
.sig


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 recommendation

reply to aurgathor
For those high powers and low frequencies I would suspect a DC coupled amp. Coupling caps would have to be very big & expensive, and would likely still roll off the bass a bit.

I'm still looking at the point of failure pictured above, that's going to be very stressed flex point, strands of the wire may be failing, causing the heating as well.


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
·Frontier Communi..
Those failures look *really* strange to me. Maybe the wires are not long enough and around Xmax they are being pulled, or the wires are not good enough for the application -- they start to fail, and when enough strands are broken the leftover just burns up.

Methinks it shouldn't be too difficult to fix them as long as a proper wire can be obtained.
--
.sig


mackey
Premium
join:2007-08-20
kudos:13
reply to joel321
Have you checked the speaker wires to make sure one of them is not grounding out? I can see what looks like a rub mark at the very top of the 1st speaker pic. If the amp connects one of the output terminals right to either + or gnd and that wire shorts out it would create a lot of heat and burn the wires and would not shut off even if the amp goes into protect.

/M

iknow_t

join:2012-05-03
reply to aurgathor
said by aurgathor:

An AC coupled amp should have a big capacitor at the output, thereby preventing DC going out to the speakers.

A DC coupled amp doesn't have a cap, and if it malfunctions in certain ways, some DC can go to the speakers.

The crossover for midranges and tweeters normally contain a series cap, so they're immune, but woofers can be damaged by it.

this is his second amp. they both did the same thing. maybe there's a design flaw in the speaker. those leads that burned out look to be at least 12 gauge. since you have a very expensive system, this will protect your speakers.
»www.musiciansfriend.com/pro-audi···rotector


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
reply to joel321
Get bigger amps and higher rated speakers, and run them at a lower percentage of their rated maximums.

They will last longer.
--

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Or simply turn down the volume a little.

Save your hearing as well as the speakers.


ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
reply to iknow_t
said by iknow_t:

since you have a very expensive system, this will protect your speakers.
»www.musiciansfriend.com/pro-audi···rotector

Where is the OP going to get the AC power to run this device??

joel321

join:2013-04-13
USA
reply to joel321
OT, This made me laugh...

quote:
Or simply turn down the volume a little.

Save your hearing as well as the speakers.
True but low HZ do not damage your hearing as much as high Hz from what I have experienced. Very low Hz your body shakes and your chest shakes while high Hz your ears hurt. Like a firecracker being popped next to you compared to a low Hz that the ear can barely pick up.

Very low Hz that the ear can pick up have less direction than high Hz. I believe the ear cannot hear below 25-30Hz and that's where I like it most of the time.

Low Hz do less damage to the ears?


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 recommendation

It all hurts your hearing over time.. I've been very tempted to put up a "sponsored by Miracle Ear" banner at a car audio event..

iknow_t

join:2012-05-03
reply to joel321
I should have noticed this much sooner, but the first picture of the speaker reveals what happened. it's NOT overpower. if it was, the wires on the speaker terminals would have been overheated also. the connections that broke are at a mechanical stress point where they are being held rigidly. poor design, and that manufacturer just discontinued it without a word!. that Boston speaker looks much better. try that instead of having to replace this disreputable manufacturer's speaker many times.


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 recommendation

said by iknow_t:

I should have noticed this much sooner, but the first picture of the speaker reveals what happened.

Humm, seems like I said that a few days ago.