Subwoofer to Amp Wattage

Airplay355

What if the clipping comes from the source and is amplified by the amplifier resulting in a blown speaker? Is that still overpowering a speaker?

MacLeod

OK. So Im competing in a national car audio competition organization with no gear?? And I suppose Cody has been imagining working as an installer all these years and those SPL competitions he's been to were all a mirage??? Gotcha.

The misconception of underpowering kills speakers comes from when you use a small amp it will be easier to push the amp into clipping which results in a signal being sent out that is limited only to the amps input voltage which comes out to 2-3 times the amps rated power. So a 50 watt amp clipped, would make 125-150 watts. Now if you have that 50 watt amp hooked up to a 75 watt speaker youre gonna fry it. BUT it wasnt because it was underpowered - it was because it was overpowered and it was that overpowering that either ripped the suspension apart or melted the voice coil.

The misconception that distortion kills speakers is that when you push a speaker to its mechanical limits (which only happens when you overpower it), it distorts and if you continue to push it too hard, it will finally blow. So some think that the distortion killed it because it was distorting before it blew when in fact it was the overpowering that did it in. Just like being shot by a gun. Its not the loud bang that kills ya, its those pesky bullets. A speaker doesnt care how distorted the signal is its being fed - so long as its below its thermal and mechanical limits.

In the fake lanes Ive been faking competing in the last 3 years, Ive seen several fake cars blow mids, tweeters and subs with power as clean and pure as the virgin Mary herself. A lot of SQ guys run several hundred watts RMS per driver (not me of course because Im faking) and when youre running a 400 watt amp to a single midrange, that is more than enough to rip it apart.

Airplay355 wrote: »

What if the clipping comes from the source and is amplified by the amplifier resulting in a blown speaker? Is that still overpowering a speaker?

No. The signal coming from the source is passive. If it clips, the amplifier will receiver the clipped signal as distorted and reproduce it as such but not at the same level the amp would be at if it were clipping.

CRESCENDOPOWER

exalted512 wrote: »

Maybe you're not understanding, so let me try to make it as clear as possible.

OVER POWERING A SPEAKER IS THE ONLY WAY TO KILL IT.

I've seen many speakers blow under conditions where you can not audibly hear the speaker meeting its mechanical limits, but it was getting pushed passed its thermal limits.

Having headroom is just fine. If you have a 500 watt subwoofer and a 1000 watt amp, that is fine, if you set the gains accordingly. But then don't turn around and say I have a 1000watts going to my 500w sub and its doing fine. No, you have 500 watts going to a 500w sub and its doing fine.

Also, its highly unlikely your bookshelf system was getting anywhere near 500w rms and it not blow unless you only played it for less than 15 seconds.

-Cody

LOL,

The whole reason one buys a higher powered amplifier is to not use all of the power so that the amplifier has no chance of clipping. Of course someone could blow a speaker with a higher powered amplifier than what the speaker is rated at but if he, or she does they are an idiot. There are limitations to what some speakers, or woofers can do.

fatalize

back on topic please people
okay the sub i plan on buying is either this
http://www.amazon.com/dp/B000PF7SG4?smid=ATVPDKIKX0DER&tag=nextag-ce-tier5-delta-20&linkCode=asn
or this
http://www.amazon.com/dp/B000EOM8EI?smid=ATVPDKIKX0DER&tag=nextag-ce-tier1-delta-20&linkCode=asn
and the box i plan on using (dont mind the photoshop :P)


any advice on the amp i should get or anything else would be greatly appreciated.
sorry for my absense i was away for the weekend.
thanks
or you can sugest a sub and box for me if mine are ****. lol
also if you would like to know the head unit and speakers im using, just ask.

eloplayspolo

not to be negative here.... but both those speakers are complete crap.

fatalize

then give me suggestion, thats what i asked if you think there crap

exalted512

rdb2001 wrote: »

What kills me on here is that everyone on here who have a millions of post thinks they are gods gift to sound and speakers. You obviously dont know much about what you are saying. Read up on an speaker, under powering the speaker hurts that speaker more than overpowering, hence why speakers 9 times out of time have bad sound quality when being underpowered. Before you type read up on what you are saying. Just because you are on polk, that doesnt mean you know everything. I have found that all the regulars on here seem to think they know everything and try to gain up on new people who have the same or more knowledge than you might have. I compete in the car audio relm and know what I am talking about. I never said you can overpower it alot, but you can blow it easier underpowering it than overpowering it a little. So before you go telling me what I dont know what do you have to prove you even have a system and I am not talking about posting what you have. I mean pictures. Because alot of you get on here and claim to have so much but probably dont have any of what u say.

YOU still have not answered why a speaker getting less power than its rated for is more likely to kill it. How that even begins to make sense is beyond me. Also, sound quality has nothing to do with how much power you give it. Its still going to play the same at 10w or 50w. Please do not associate 'louder' with 'sounds better' as so many in this hobby do.

As far as me, I'm a full time installer. I don't have a sub system in my truck right now, still working on the new setup. When you do it 6 days a week 9.5 hours a day, it gets to be the last thing I want to do when I get home.

Here are the picture's you requested:
http://www.cardomain.com/ride/531337/9

Your turn.

only126db wrote: »

Ya know, its funny I run into so many conflicting theories on underpowering speakers, I'm begining to think nobody really knows...

JBL says clipped signals will kill a speaker...

Rane says no they wont.....

Yet I have burnt woofers in years past by over driving the amplifier.

I have also used many speakers well over their rms ratings with very good results.

And exalted512, I will test my amplifier output just for you, I have a program I am wanting to test out and see for my self what my system does, of course it will be test tones, I will evaluate using a couple tones and relay the info to you and let you know what my Polks are handling in their ported boxes...

Well, clipping by itself does not kill speakers. Unfortunately, there are so many stupid people in this industry, many manufacturers will dumb things down. As in the myth that underpowering kills speakers. It does not. But then you get the idiots that dont want to pay for a larger, quality amplifier and get a smaller POS, turn the gains all the way up and blow their speakers because the clipped signal they were sending their subs was way beyond their power handling. Then, people say the cause is underpowering speakers. It was not. It was installer error. And having a larger amplifier does not mean its harder to clip. Its just the same. But when that amp does clip, its going to kill a speaker in half the time that it will with a smaller amp.

I'm curious as to know your testing methods. There's not a whole lot of people that have access to the tools needed to properly test the output of an amp. 99% of shops dont even have the equipment (we are one of them). You can get an estimate by measuring the AC voltage speaker outputs, but its only maybe 75% accurate.

CRESCENDOPOWER wrote: »

LOL,

The whole reason one buys a higher powered amplifier is to not use all of the power so that the amplifier has no chance of clipping. Of course someone could blow a speaker with a higher powered amplifier than what the speaker is rated at but if he, or she does they are an idiot. There are limitations to what some speakers, or woofers can do.

Actually, a lot of people will turn up a larger amplifier just as much as they would have if it was smaller. This is from years of experience from selling the damn things. Then when the customer returns with bad speakers and tells me "I read on the internet overpowering a speaker is better than underpowering it" I have to sit down with them and explain how that is wrong. That is why I don't let it slide when I hear people talk about it on the internet. IT IS WRONG.

I have an amp that is rated at 50x4 @ 4, does closer to 180ish x4 @ 4 ohms, and I have each channel going to a tweeter and a 3" midrange. The gains are set at absolute 0. Its still gets pretty loud and the sound is amazing. i'm not saying, dont get a bigger amplifier, all I'm saying is set the gains accordingly. And nor do I tell people i have almost 200w going to each midrange and tweeter. I do not. I have an amp capable of that, but in real life theyre getting 50w when I crank it up.
-Cody

exalted512

fatalize wrote: »

back on topic please people
okay the sub i plan on buying is either this
http://www.amazon.com/dp/B000PF7SG4?smid=ATVPDKIKX0DER&tag=nextag-ce-tier5-delta-20&linkCode=asn
or this
http://www.amazon.com/dp/B000EOM8EI?smid=ATVPDKIKX0DER&tag=nextag-ce-tier1-delta-20&linkCode=asn
and the box i plan on using (dont mind the photoshop :P)


any advice on the amp i should get or anything else would be greatly appreciated.
sorry for my absense i was away for the weekend.
thanks
or you can sugest a sub and box for me if mine are ****. lol
also if you would like to know the head unit and speakers im using, just ask.

What is your budget for the amp/subs/wiring?

What kind of car is it going in?

What radio do you have?
-Cody

fatalize

car is a 1991 nissan maxima, and my budget is average/ish, haha i dont want anything way over the top bass, just enough to sound reasonably good.
im looking at getting this head unit
http://www.amazon.co.uk/Kenwood-KDC-W312SAY-Radio-MP3-Receiver/dp/B000WE7YXK/ref=dp_cp_ob_ce_title_1/279-0664623-8079955?ie=UTF8&qid=1225117311&sr=1-6

feel free to help me out and request/give links to a good setup or combo of things to get.
thanks.

Jstas

Why does this forum always get afflicted with **** like these? Then, when I yell at them and tell them they are ****, I get "called out" to furnish proof and told I'm a big meany, angry and a know-it-all. But if everyone else does it, it's "discussion"?


You morons want your proof? Here: http://www.splung.com/ It's called physics and you can't change the rules just because some half-assed "testing" in your garage shows "undeniable proof" that what you think is right is right and the greatest minds in history are dead wrong. What's that? You don't need no stinkin' math to tell you what you already know? Guess what champ, go get an 'effing education and THEN come back and tell me and everyone else here how wrong we are. I'm betting you'd have an epiphany before then and be too embarrassed to show your user name here again. But then again, the surer bet is on your arrogance and blissful ignorance in thinking that you have all the answers.

Again, I maintain as well as others here, that any success any yahoos like you have had has been pure luck or through the guidance of others who actually know what they are talking about and have set you up with very conservative systems so as to avoid a the pain of having to deal with monumental asshats such as yourselves who blew their junk up and have no idea how or why they could have caused it.





fatalize, you need to furnish more complete info. I agree with the others, the subs you have chosen are not the best idea. I would honestly go with a Polk Audio DB series sub and a Profile California series amp because you seem to be on a budget and they will give you the best bang for the buck. Also, the DB subs seem to be very forgiving in their ported dimension so a generic ported box from a company like Q-Logic should give you a decent amount of performance and not cost an arm and a leg. If you are planning on competing, you have a great deal to learn before you can be successful.

The "Air Hole Thingo" is called a port and it's pretty important to the whole design. If you are planning on building your own box, decide on a woofer and post it here along with the space that the box has to fit in and I will help you put together a vented enclosure that will compliment the woofer as best as possible. They require some complex math equations and I have design software that I can use to model enclosures quickly and easily without having to fuss with all the math.

I also feel I have to apologize for the sucktastic behavior of only126db, CRESCENDOPOWER and rdb2001 for not only the behavior they have exhibited but the perpetuation of myths as fact and for purporting misinformation as common sense and under general acceptance. Nothing could be farther from the truth.







Was that too harsh? You know what? To paraphrase Mr. Grand, that's probably going to offend someone and they need to know ahead off time that I don't care.

Jstas

fatalize wrote: »

car is a 1991 nissan maxima, and my budget is average/ish, haha i dont want anything way over the top bass, just enough to sound reasonably good.
im looking at getting this head unit
http://www.amazon.co.uk/Kenwood-KDC-W312SAY-Radio-MP3-Receiver/dp/B000WE7YXK/ref=dp_cp_ob_ce_title_1/279-0664623-8079955?ie=UTF8&qid=1225117311&sr=1-6

feel free to help me out and request/give links to a good setup or combo of things to get.
thanks.

Are you in in the U.K.?

If so, your selection of audio gear tends to be different from ours. However, specs are specs and if you can provide links or specs of equipment you are looking to use, that would be better than this piecemeal process of dragging info out of you.

The specs are the headunit are OK. I like the 24 bit DA converter but I think you would be better served finding something with a 4V pre-amp (RCA) output level or better. If your budget allows of course.

As far as budget, "average-ish" doesn't help. We need a number, dude. Can't select components with a budget in mind if you don't set a number and say how high above or below that number you are willing to go.

fatalize

sorry if im making you guys do so much work/math stuff but ive decided to get a polk
http://www.polkaudio.com/caraudio/products/15inch/speakers/mm2154/
what amp, and box should i get?
i have a 1991 nissan maxima (lol :P) the boot is fairly large

fatalize

money isnt all that much of an issue, id be willing to spend another ~$600-$700 on top of that sub (might be able to pull out a bit more if i have to )

only126db

exalted512 wrote: »

I'm curious as to know your testing methods. There's not a whole lot of people that have access to the tools needed to properly test the output of an amp. 99% of shops dont even have the equipment (we are one of them). You can get an estimate by measuring the AC voltage speaker outputs, but its only maybe 75% accurate.


-Cody

I have a program which determines output power by calculating amp current draw, start voltage, voltage drop, output volts a/c, output amps a/c, speaker re, spl, and by what frequency you test at.

The program determines impedance rise, output rms, and amp efficiency if you have all the input values that are required, of course the only one I will not have is spl since I dont have access to a powerful enough meter at this moment, but I believe that will only affect the impedance rise.

So to fully use the program you would need a clamp meter, a couple DMM's, and an spl meter to be accurate, plus 3-4 pairs of eyes.

But with one DMM a clamp meter and a long test tone you can get pretty darn close.

I personaly have not used it with my actual measurements but several people on a different forum who know there actual power through competition say it's accurate.

only126db

Jstas wrote: »

I also feel I have to apologize for the sucktastic behavior of only126db, CRESCENDOPOWER and rdb2001 for not only the behavior they have exhibited but the perpetuation of myths as fact and for purporting misinformation as common sense and under general acceptance. Nothing could be farther from the truth.


Was that too harsh? You know what? To paraphrase Mr. Grand, that's probably going to offend someone and they need to know ahead off time that I don't care.

Dont appologize for me, we sure are glad you have software....

I do too.....

Anyone else?

And so not to keep jacking this guys topic if you feel like seeing what mine does you can go to my post
"report on polk death" you know the one...:rolleyes:

fatalize

yeah this has kinda gone off track, but if anyone could post some helpfull info/replys to the last couple messages i typed up. id be gratefull

only126db

fatalize wrote: »

car is a 1991 nissan maxima, and my budget is average/ish, haha i dont want anything way over the top bass, just enough to sound reasonably good.
im looking at getting this head unit
http://www.amazon.co.uk/Kenwood-KDC-W312SAY-Radio-MP3-Receiver/dp/B000WE7YXK/ref=dp_cp_ob_ce_title_1/279-0664623-8079955?ie=UTF8&qid=1225117311&sr=1-6

feel free to help me out and request/give links to a good setup or combo of things to get.
thanks.

Ibelieve thats the equivalent of the US model 318 which I own, decent quality deck for the price....

Three things I dont like about it are:

1) One set of RCA outputs.

2) Volume knob is multi function and if changing volume and you hit a bump you will switch the eq preset and it automaticaly goes to a setting with high bass output.

3) The trim ring tends to sag a tiny bit which will sometimes keep a cd from ejecting fully(push down on cd lip a tiny bit and it'll eject).

As for a budget amp I have to agree with jstas(hate to say it).

Profile amps http://www.profileusa.com/products_amps_ap.cfm

Crunch http://www.maxxsonics.com/crunch/PZ_main.html

Hifonics http://www.maxxsonics.com/hifonics/amps_brutus.html
http://www.maxxsonics.com/hifonics/amps_zeus.html

Cadence http://www.cadencestore.com/ProductCart/pc/viewCategories.asp?idCategory=125

As for a budget Subwoofer I would recommend:

RE Audio http://www.reaudio.com/specs.html#sp_re

Mach5 http://www.mach5audio.com/zen/index.php?main_page=product_info&cPath=65&products_id=186

DIY http://www.diycable.com/main/product_info.php?cPath=24_93_150&products_id=653

RD Audio http://www.rdaudio.net/studio/studio.htm

Jstas

only126db wrote: »

Dont appologize for me, we sure are glad you have software....

I do too.....

Anyone else?

And so not to keep jacking this guys topic if you feel like seeing what mine does you can go to my post
"report on polk death" you know the one...:rolleyes:

I don't care what your software does, I don't care about your graphs of how you made a flat and progressive response from a sealed enclosure and compared it to the peaky response of a ported enclosure. I don't care and like the other people in this thread, I think you're a mental midget that thinks he's got everything figured out. And to think I actually stuck up for you when you got here and someone was bagging on you.

I offered to help the guy out by giving him calculated dimensions on his sub box if he's going to do it himself. He is obviously not in the know and I can help so I offered it.

fatalize

thanks for all the links only126db
ill post back once i pick out some i like, and you guys can tell me if its a good combo

fatalize

screw it, haha, ill look at the links tommorow its 4:30 am here :P
goin to sleep

Jstas

fatalize wrote: »

yeah this has kinda gone off track, but if anyone could post some helpfull info/replys to the last couple messages i typed up. id be gratefull

Um, I did give you recommendations. The problem is that I can list all the fun stuff I would use here in the United States but it doesn't translate to your market there in the United Kingdom. Alot of the stuff I can get here, you can't get there. There is a difference so do your research and give us some ideas of what you are looking at AND a budget figure.


As far as what you posted already, I'll reiterate. Go higher in the lineup for the Kenwood head unit. The 300 series decks are marginally a step above entry level and really not worth the time unless you just need tunes for a work truck or something. Go with something in the 500 series or 600 series.

In fact, I would spend the extra coin and go with at least this unit:

http://www.amazon.co.uk/KENWOOD-KDC-W6541U-USB-MP3-Radio/dp/B00157SSVU/ref=sr_1_1?ie=UTF8&s=electronics&qid=1225130599&sr=1-1

You can't really go wrong with a head unit from Kenwood, Pioneer or Alpine. they are all built like tanks and offer a bunch of features for not a bunch of dollars. You just have to find one that will support your needs and desired performance.

If you are honestly serious about the MM2154, get this amplifier:

http://www.amazon.co.uk/Phoenix-Gold-R5-0-Octane-Amplifier/dp/B0002BAD86/ref=sr_1_42?ie=UTF8&s=electronics&qid=1225130972&sr=1-42

Or something similar in quality and power. Again, I do not know what you have access to in the U.K.



That's the best you are going to get from us unless you start giving some numbers and ideas of what you have access to. And Amazon.com is not the best place to be buying audio equipment. They typically only stock thee high volume brands which are not highly regarded. Most of the stuff there is from Lanzar, Legacy and Pyle. Not exactly high-end...well, hell, not exactly mid-level brands there.

fatalize

where did you guys get the idea that i was living in the UK :P
i live in australia

eloplayspolo

because the amazon link you posted was .uk

fatalize

o, i just followed a link i got from someone i didnt know it was a UK link

rdb2001

I am posting a reply from a thread on this same subject.

McLoki
Polk Expert


Member Sales Rating: (4)


Join Date: Aug 2004
Location: Central Illinois
Posts: 3,975

---

No. (for example, I have a 500 watt amplifier but speakers that handle somewhere between 150 (LSi7's) and 350 (LSi15's) watts)

Personally I like the watts of the amp to be greater than the watts of the speaker. (this is not required by any means - but I feel it is safest to do it this way)

Reason being, it is pretty hard to blow a speaker with to many watts when playing music or movies. (it can happen, but you usually know when it is about to happen. - soundstage just collapses and everything just starts to sound wrong)

It is pretty easy to blow a speaker if your amp is not strong enough though because the amp runs out of steam but still tries to power the speaker. When it does this it sends a distorted signal to the speaker and the tweeter will usually fry.

In my example above - it would be much easier for me to blow my speakers using a 50wpc reciever than a 500wpc amplifier. It sounds backwards and wrong, but that is the way it is. Amplifiers running out of power is what usually blows speakers - not amplifiers with to much power.

Michael


And to Macloed

For you to say clarity does not come from whether you power a speaker with 10 w or 50 w. ARE YOU SERIOUS!!!!! Thats blasphemy. For you to know so much how can you possible say that. On another note, I respect everyones opinion. I also saw your setup and had the same underseat box setup and it sound terrible. I wanted to see how you got that to sound good. I have an avalanche, and I ended up going to a custom setup in my bed with a 6 cubic foot box and 1 kicker comp vr 15. I would say this was the best thing I could have done. It sounds great

JSTAS

You dont offend, you are one those big online talkers who wants to questions someones intellect when yet you do not have any yourself. I know that you are just one of those people who likes to hear or see yourself talk. Your post shows me how you really dont have a clue. You also told the guy to get a db series polk and a q logic box. Those are some of the worst built prefab boxes you can buy and polk db series speakers are just cheap. That set up is a terrible choice. When you actually post something that has some substance to it, I will be glad to read it.

only126db

From a Powerbass rep on another forum...

"We really don't have many returns on the 2XL and 3XL lines. All the returns I've seen have been from underpowering them"

eloplayspolo

polk db subs are NOT cheap. and if u think they are GTFO of these forums.

Q-logic- i agree, i rather put my sub in my closet.

exalted512

rdb2001 wrote: »

No. (for example, I have a 500 watt amplifier but speakers that handle somewhere between 150 (LSi7's) and 350 (LSi15's) watts)

Personally I like the watts of the amp to be greater than the watts of the speaker. (this is not required by any means - but I feel it is safest to do it this way)

Reason being, it is pretty hard to blow a speaker with to many watts when playing music or movies. (it can happen, but you usually know when it is about to happen. - soundstage just collapses and everything just starts to sound wrong)

It is pretty easy to blow a speaker if your amp is not strong enough though because the amp runs out of steam but still tries to power the speaker. When it does this it sends a distorted signal to the speaker and the tweeter will usually fry.

In my example above - it would be much easier for me to blow my speakers using a 50wpc reciever than a 500wpc amplifier. It sounds backwards and wrong, but that is the way it is. Amplifiers running out of power is what usually blows speakers - not amplifiers with to much power.

1. Please learn how to quote.
2. If you are setting your amplifiers up right, you will never clip them. If you are clipping them, it is installer error. And you can clip a bigger amp just as easily as you can a smaller amp, but when the bigger amp clips, its going to fry your gear a lot faster.

rdb2001 wrote: »

For you to say clarity does not come from whether you power a speaker with 10 w or 50 w. ARE YOU SERIOUS!!!!! Thats blasphemy. For you to know so much how can you possible say that. On another note, I respect everyones opinion. I also saw your setup and had the same underseat box setup and it sound terrible. I wanted to see how you got that to sound good. I have an avalanche, and I ended up going to a custom setup in my bed with a 6 cubic foot box and 1 kicker comp vr 15. I would say this was the best thing I could have done. It sounds great

i believe i was the one who said that. no, its not blasphemy, its the truth. The properties of a speaker do not change as they are given more power, theres not some magic volume where you start hearing symbols at volume 15 that you didnt hear at volume 10. Its all the same. Unfortunately, 90% of the car audio community associates 'louder' with 'sounds better,' like yourself.

I dont have any bracketry under my rear seat like an avalanche does, that and fiberglassing the bottom allowed me to get a good amount of air space. Nothing like 6 cubes, but it was also a sealed box. I would have liked to see what it could do with more power behind it, but the alternator wouldn't have taken anything more that what I had. Since then, I've moved to a newer truck which will eventually get a pair of 250+A alternators.

rdb2001 wrote: »

JSTAS

You dont offend, you are one those big online talkers who wants to questions someones intellect when yet you do not have any yourself. I know that you are just one of those people who likes to hear or see yourself talk. Your post shows me how you really dont have a clue. You also told the guy to get a db series polk and a q logic box. Those are some of the worst built prefab boxes you can buy and polk db series speakers are just cheap. That set up is a terrible choice. When you actually post something that has some substance to it, I will be glad to read it.

While I wont dispute that q-logic has starting making crappier boxes over the last few years, the db series are by no means 'just cheap'. They might not get as loud, but they sound a helluva lot better than your CVRs. And this is coming from someone who carries Kicker in his shop, but not Polk.
-Cody

exalted512

only126db wrote: »

From a Powerbass rep on another forum...

"We really don't have many returns on the 2XL and 3XL lines. All the returns I've seen have been from underpowering them"

Reps are not always the smartest people in the world.
-Cody

only126db

exalted512 wrote: »

Reps are not always the smartest people in the world.
-Cody

You got me on that one, most I talk to dont know jack isht.

I tossed this out there just as a jab....

I honestly couldn't say whether this is fact or fiction on the underpowering, there is so much back and forth on the subject.

I wish I had the test equipment to be able to do the testing myself and prove the outcome one way or the other.

I generally tend to get an amp rated higher than my subs just due to the fact that music does not generally contain a flat non fluctuating signal as the signals used to determine/verify rms on subwoofers. (pink noise)

A signal producing 50% power and 200% peak power evenly equals 100% average which could be recognized as rms.

A 100watt rms sub getting 50 watts with 200 watt peaks evenly = 100rms, now if your amp is rated @ 100 watts and just barely makes that mark, with a supply voltage drop(if) you wont even hit that mark, but have a good chance of having crappy sound.

However if you have an amp rated to do 150 rms with the voltage drop and everything else you will have the ability to provide your sub with the needed power and have some extra for those musical peaks.

(The wattages above are just for illustration for ease)