I hear this all the time from customers. There’s a big misconception when it comes to understanding why speakers blow. Many people think that too much power damages speakers. And that’s true to an extent, but I’d say 95% of the time it happens because of the exact opposite. Sometimes my customers dreamily reminisce about the system their friend had and how loud they played it and they describe to me that it was “So loud, the speakers couldn’t handle it”. And really that is not the case at all!
So why do speakers blow? Speakers are easily damaged from a LACK of power. Distortion happens when you run out of power. The speaker starts breaking up and you hear fuzzy and garbled sounds, sometimes crackling and gritty noises. This is actually the sound of the amplifier clipping. Whether it’s the amp built into the radio or it’s a separate amp that you’ve powered up with a thick power wire coming from the battery, you will run into the point where the amp runs out of power and starts clipping. That is when you start to hear distortion. And over time, distortion will cause the voice coil in the speaker to heat up and break apart and shortly thereafter, it stops making contact completely and thus you have blown speakers.
So how do you prevent this from happening? It’s all about the power. If you like it loud, you need the power to back it up. You need the right amplifier and you need to supply it with the proper power wire.
But what if you have a 1600 watt amplifier and a 1200 watt subwoofer and you still manage to damage your subwoofer? This can happen due to a number of reasons, and I see it happen often enough that I feel I need to explain this.
Typically when a customer comes into my store and relays this dilemma to me, I immediately ask them if they know the RMS rating of the amplifier and the subwoofer. They usually repeat to me what they originally told me: they have a 1600 watt amp and a 1200 watt subwoofer. So I ask to see this 1600 watt amp and this 1200 watt subwoofer and I can quickly see that these are the numbers largely plastered on the equipment. They are not the true power rating, but simply a peak power rating which is the number that grabs everyone’s attention.
After closer inspection, I see the amplifier has two 25 amp fuses and there is 8 gauge wire ran to it. If this amp was really capable of 1600 watts, it would need a much larger gauge wire like 2 or 0 gauge. However, with two 25 amp fuses, I can tell right away this amp is really only putting out about 350 watts RMS. And the subwoofer? After looking the model # up on the internet we find it’s rated at 600 watts RMS. So what does all this mean?
We are under powering the subwoofer and pushing the amp into clipping which is distorting and damaging the speaker. If we really wanted to use the 600 watt subwoofer, we would need to supply it with an amplifier pushing out about 600 watts RMS. And that’s not the only problem here. To really pull that amount of current, you need to use 4 gauge wire. You could get away with 8 gauge, but 8 gauge is only capable of pulling so much current, about 500 watts safely. At some point, you will end up starving the amp for power. That means you’re not getting your full 600 watts out of your amp, which means you’re once again, under powering your subwoofer and running the risk of damaging it.
So here are the key factors to keep in mind so you can avoid damaging your speakers:
1) Always check the RMS rating of your speakers and make sure it matches or is close to the RMS rating of your amplifier. Don’t pay attention to peak power ratings, they are very misleading. Companies use this number to grab your attention and sell you on their product.
2) Always make sure you are running the proper gauge power and ground wire based on the RMS rating of the amplifier. If you don’t trust the rating on the amplifier, check the fuses on the amp and use an amps to wattage calculator to determine the true output.
3) Never play your car stereo speakers with distortion. Remember, distortion is what damages speakers.
I’d be happy to answer any questions anyone may have and post any comments. Thanks for reading my tips. I’ll be back next week with a post about how important it is to have the proper box for your subwoofer with tips and tricks on building it.
12 Comments
I’ve been installing car audio off and on for friends for 10 years now. I know way more than the average user and know all about matching RMS wattage, wiring dual voice coils in series vs parallel. It should be noted that I’ve had the SAME Directed D800 all this time and it is STILL killing it. My first set of subs were two 12″ xlpods and they lasted 5 years for me before I sold them to a buddy. Two years ago I finally got around to getting a Kicker 12 CVT and it had been nothing but solid. I’ve run the “big three ” on my car and use 0 gauge wire to both ground out batteries, engine, and beef up powered to alternator.
I know my way around this stuff but one thing has me completely stumped. Tonight marks the THIRD sub I’ve installed in her 09 Dodge charger. All of hers have been kicker comp VR 12’s dual at 4 ohms. The first amp was a boss POS so assumed that was the culprit. It had an odd RMS rating at 2 ohms. Seemed like the paperwork said it was double what I figured it should be. It was the slightly older style compvr (bright silver w red logo). When that blew, I said we’re getting you a kenwood x500-1 and a newer model CVR 12. They are SOLID SUBS! Sub lasted a month or two. Blown voice coil. Got her money back. Bought same model sub from Sonic Electronics (always had good experiences with them), lasted three and a half months…tonight it’s blown. Starting to worry about the Charger’s electrical system. I’ve got 4 gauge power and ground directly to the amp. Can’t find my multimeter but it rattles BAD in and out of box. What am I missing? I’ve never had a problem out of my stuff! EVER! And she really doesn’t push it hard.
Hey Nick,
You must be dealing with distortion somewhere, that is what kills speakers. So either your gains are too high and the signal from the amp is clipping or your signal going into the amp is distorted. Best bet is to use a scope to measure for distortion. If you only have a regular multi-meter, JL Audio provide details on how to properly tune so you don’t have distortion OR you can buy one their new RD amps which give you an LED indication on the amp when the signal is clipping. If you want to use an amp you already have, check out page 14 of this owner’s manual which provides an easy 9 steps to properly set your amplifier settings.
By the way – the damaged subs may have also damaged the amp, I have seen this happen before too because the amp basically ends up seeing a dead short. So you may need to start from scratch and just really take the time and steps to make sure the signal is not distorted going into the amp and the signal is not distorted coming out.
I think it is important to clarify a bit when making the statement that “too little power can damage a speaker”. This was an ongoing debate that raged on RAC for DECADES.
Ultimately, TOO LITTLE POWER DOES NOT POSE A DANGER TO SPEAKERS. But clipping and distortion CAN. First of all, the argument that during extreme amplifier clipping, when the wave form as at the “flat” part (as that is what clipping is after-all), the voice-coil is momentairly motionless (the “still VC argument), and this sudden freezing of the voice coils cause them to fuse with the former IS BOGUS. The VC is really NEVER still long enough for any thermal damage to take place.
The two most possible causes for speaker damage, AND RIGHT HERE FOR THE RECORD I WANT TO SAY THIS FALLS UNDER USER ERROR, MORE THAN STRICTLY SPEAKING TOO LITTLE POWER, is that when an amplifier begins to heavily distort, it may begin producing unwanted higher end harmonics. If an amplifier does not have proper output filters, it may under heavy clipping begin to produce these ultra high harmonics that the speaker was NEVER DESIGNED TO PLAY. In the case of tweeters, which might not employ any low-pass filters, this can be especially dangerous as the tweeter will try to play frequencies in the “dog range” and the VC will simply melt-down from trying to move fast enough to produce these frequencies.
The other “possible” way an underpowered amp may damage a speaker is when it is producing an INCREDIBLY high level of distortion, it maybe producing MANY TIMES it’s rated power RMS. You may have a 50 watt RMS amplifier powering a 70 watt speaker, should be all good right? But when that amp goes into heavy clipping and distorting, it may be producing MANY times that 50 watts, perhaps as high as 200 watts (depending on the amp’s voltage rails, et al).
But again, I classify these two occurances as operator error, RATHER than the assertion that too low an amp may damage a speaker. Heck, you could have a speaker play distortion ALL DAY LONG, and as long as it stays within the speakers operating limits, no problem. There is nothing inherently “dangerous” about distortion. It is what the distortion represents (as discussed above) that is dangerous.
Thank you for your great site!!!
Nick aka MOSFET on CAF
Hey Nick – I think we’re really saying the same thing, but you’re going off on the technical deep end. In my 15 years experience people blow up speakers because they have too little power. They want to play it louder than the amplifier is able to produce (without distortion). They think distortion happens because and I quote,
“the speakers can’t handle the power”. Their understanding is totally backwards. So to try to explain it in layman’s terms – they blew their speakers because they were driving them with too little power, clipping the amp and causing distortion. So my solution is to sell them an amplifier and speakers that can handle the output they desire and make it so their system is plenty loud for their tastes without ever running the amp into distortion.
For the record, I have had people damage their speakers playing distorted signal through them when the distortion has been a result of the audio source (like SiriusXM radio or music from You Tube or any other highly compressed garbage audio sources). So I’m not sure about your comment thinking their is nothing inherently dangerous about distortion because I’ve seen distorted and highly compressed recordings cause damage when there is no clipping actually occurring within the amplifier or head unit pre-amp.
Hi Annie I bought a 1600 watt ma audio amp It has 4 40 amp fuses I am running a 4 gauge wire. I hooked this amp up to a jl w3v2 and in a matter of minutes smoked it. I figured maybe it’s just an old sub. I then hooked up a nib boss phantom smoked it in about two min. So now I’m on to a 15 kicker cvr havent smoked it yet but starting to get smells from speaker. Do u have any idea what could cause this my amp blows every sub input it two.
Hi, Massive Audio has a lot of different models that claim to be 1600 watts. I’m going to guess based on the fuse rating, that the amp is around 1000 watts RMS. WAY too much for any of the subs you mentioned. Even the CVR only handles 500 watts RMS. If you can tell me the exact model number, I can shed some more light on this for you.
It’s all about matching the power handling, the impedance and properly setting gains/crossovers etc on the amp. If you can tell me the model number of the amp, what kind of car this is in, what head unit you are using I can give you some more detailed advice on what sub is a better match, what impedance to get, and how to tune the sub amp. For more info on sub amp tuning, check out my post on sub amp tuning here.
I have a QX1-2400D its the older model, 4 30watt fuses. After market head unit Jvc. yes they are dual 4ohm. my wiring was a wire goin positive on one terminal of sub to positive of other terminal on same sub then same with negative then positive and negative wire from one terminal to amp and same with other sub I joined the other subs wires with these and plugged it in worked for a lil then boom gone
Hi Logan,
Okay so you definitely had your box wired down to 1 ohms, which means that amp was pretty unstable and pushing out 1800 watts RMS, way too much for those subs. You can still use that amp and subs, but you’re going to have to wire it differently. I want you to series each sub. So on each voice coil you’ve got 2 sets of positives and negatives. You’re going to take one side of some speaker wire and link one positive from one voice coil to the negative of the other voice coil kind of like what is shown. Some subs have the voice coil terminals right next to each other and all you have to do is use a little jumper cable. See how the positive of one voice coil is linked the negative of the other voice coil? That leaves open one positive and negative. That you will run to your amp. Do the same for both subs.
With each sub in series, they are acting like 8 ohm subs. Then by joining the wires from your subs at the amp (open positive from each sub to the amp’s positive, open negative from each sub to the amp’s negative), your amp will see 4 ohms. Now it will only put out about 900 watts. Still a lot more than you need, so go easy on those gains, like maybe around 1/4 way up. See how it sounds. That should take care of that for you.
Remember on your head unit to keep bass boost off, bass level 0, use sub level control on the deck only to adjust how much bass is heard through your system. Keep your x-over on your amp around 80 hertz low pass, bass boost off, gains low. As long as you set everything like that and your subs aren’t popping or flubbering at high volume, they should be okay.
Hi I have 2 Hifonics HFI 300watt rms 12in subs and a kole audio mono class D amp I cant seem to find anywhere the rms rating on the amp so I amp really confused and I tried lookin online and doing you amp to watt ratio deal. Clearly I dont get it because being the impatient 16 year old I am I just stuck the subs in a box hooked them up hooked positive to positive and neg to neg then into the amp and I blew one sub. (destroyed the voice coil) I need some help I dont have money cuz im young and I got another hifonics so I have to again please let me know how you think I should hook them up. Thanks a million
Hi Logan. Thanks for stopping by and posting. I totally get it about being young, wanting a system, but maybe not having enough cash to have a professional advise you on what to buy and install it for you. That’s why I made this site, so I’m happy to help you. Can you at least tell me what model amp you have? That will make a big difference in my advice to you. If you can’t find a model #, just tell me what size fuses are on the amp. That will be a good indicator of what kind of power it’s actually capable of producing.
I googled the subs you mentioned and they look like they’re dual 4 ohm voice coils, is that right? The way you said you wired it (positive to positive, negative to negative), did you do that to each voice coil as well? If so, that means you wired your box for 1 ohm. Which is pretty unstable for an amplifier. It means the amp has very little control over the movement of the subwoofer.
Blowing the sub could be a combination of several factors, wrong impedance, too little power, too much power (doubt it though), wrong setting on gains, wrong setting on crossover, etc. Let me know what model amp you have and I can give you a more detailed plan to prevent this from happening again. Also check out out my post on tuning before you wire up anything else. So homework for you is:
1) what model amp or what size fuses are on it?
2) how did you wire each voice coil and can you confirm they are dual 4 ohm subs?
3) How are you running this set up, off an aftermarket head unit or stock?
4) what size wire are you running for your power and your ground?
I look forward to helping you this figure it out!
i hooked up my subs to two ohms and (not thinking) bridged them to my amp, well i blew my amp(it stays in protection mode even with nothing but power, ground, and remote hooked up) the amp is a lanzar vibe286(really wasn’t bad for the cost) and i have two lanzar 15’s….do you think i could have blown my speakers due to my stupidity of wiring(i knew better just didn’t even cross my mind that day)
Hi Scott,
It happens to the best of us, I even hooked positive and negative up backwards to an Eclipse amp once, luckily it just popped a couple fuses : )
Did you blow them up? That’s hard to say. Did it play alright for a little bit or cut out as soon as you hooked it up? If it cut out right away the subs are probably fine.
If you have a volt meter, you can set it to the ohms sign and just hook it up the subs (the subs don’t have to be hooked up to anything) and see if they read the proper impedance. Any shop should be able to do this for you relatively easily and I don’t think they should charge for it. You could just ask them to measure the impedance of your subs as you’re in the market for a new amp and they should help you.
If they meter properly then they’re fine. The other way to check is if you press into the center of the face of the sub and goes in and out easily, it’s probably okay. As long as it doesn’t smell toasty. If the voice coil is shot or going, it will be really stiff and not smooth when you press it down and you will be able to smell burnt voice coil. Hope they’re okay!