Does underpowering a sub hurt it?

 

Bronze Member
Username: Ishkabobble55

Post Number: 77
Registered: Jul-05
lets say a 600 watt rms sub with 150 watts rms over a period of time does it hurt?
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1204
Registered: Aug-05
no it doesn't hurt it unless the amplifier is pushed into clipping which i am willing to bet that a 150wRMS amp will clip almost immediately once you begin to turn it up.

there are also recommended RMS ratings on subs you shouldn't go under, b/c the sub will not sound very well.
 

Silver Member
Username: Tdbdadrummer

Post Number: 238
Registered: Aug-05
Well Muddy a SONY 150W RMS sub will clip immediately, but I doubt a JL or something good like that would...
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1206
Registered: Aug-05
what?

a sub doesn't clip, the amp does

and any sub that requires 600wRMS on a 150wRMS amp is going to want more power than the amp can deliver, so it will clip the signal to give it more power.:-)
 

Silver Member
Username: Mikechec9

Http://www.cardomain.c...

Post Number: 971
Registered: May-05
it's the amp that clips, not the sub. and if you push that amp to the point that it would otherwise have sounded good had you supplied adequate power, you will likely be clipping the signal to achieve that volume. while jl's are efficient (which i think may have been Tyler's point), an aggressive user will still push the amp into clipping.
 

Silver Member
Username: Tdbdadrummer

Post Number: 243
Registered: Aug-05
Haha, sorry Muddy/mike, I've got a lot on my mind, an amp will clip...geez, what was I thinking...I'm just gonna go take a nap now...I'm kinda tired...
 

questions
Unregistered guest
So i got 500RMS sub now im pushing about 500 watts to it is that fine aswell:S?
 

questions
Unregistered guest
1200 Watt amp 2 channel powering 2 500RMS watt subs clipping??

Lanzar if you care to know.

Thought id be bit more specific.
 

Silver Member
Username: Audiobass10

Cape Coral, FL United States

Post Number: 204
Registered: Jul-05
A sub rated for 500w RMS being fed 150w RMS at a full clipped signal really wouldnt even hurt the sub.

Not saying this should be done, because when clipping happens there is of course distortion..and who want's distortion in their music?

Basically, what i'm saying is that you really wouldn't damage the sub even at a full clipped signal when running that small amount of power to it.
 

Silver Member
Username: Mikechec9

Http://www.cardomain.c...

Post Number: 978
Registered: May-05
"clipping signals via underpowering will not damage your sub."

yes, that's an argument that i've unfortunately debunked more than once, lol.
however, i would certainly like qualified electricians/engineers on the site to speak on it from a theoretical perspective. It's a valid point to address, imo.
regardless though, you're still asking your amp to supply power it doesn't have. like running a 4cylinder wide open imitating "fast and furious." you will likely burn it up.
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1209
Registered: Aug-05
when the amp clips the signal, it sends the sub DC, the VC's cannot dissipate the heat from DC as well as AC, so it melts the VC's.

depending on how many watts of DC the VC's can take will determine how well your sub will hold up to a clipped signal.
 

Silver Member
Username: Mikechec9

Http://www.cardomain.c...

Post Number: 982
Registered: May-05
every sub i have ever aggressively sent clipped signals to has failed. all had rms well over what the amp provided.
the argument is that the rms is a thermal rating, so clipping signals up to that point should be a moot point with regards to driver damage. but again, in practice, that theory has never held up for me in the past (those days are faaar behind me, lol). That's why i prefer overhead, and give all my drivers 50% more than the rated rms. each individual speaker.
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1226
Registered: Aug-05
"That's why i prefer overhead, and give all my drivers 50% more than the rated rms. each individual speaker."

well said, let's do lunch. LOL Upload
 

Silver Member
Username: Disturbedpriest

Post Number: 167
Registered: Jun-04
on this subject how do you know your rms rating on your amp is really putting out what it says, i think my amp at 14 volts pushest 1650 watts rms at 1 ohm and like 1200 at 12 volts, and i am running twos subs that are 600 watts rms, am i asking for trouble? 2 diamond audio tdx 10's on a alphasonik pm800 something. like a 1000 dollar amp in the book i have i got it for less *ebay*
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1248
Registered: Aug-05
you should be fine, if they start to distort, simply turn it down.
 

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 10379
Registered: Dec-03

http://www.bcae1.com/2ltlpwr.htm

that should help some in understanding speaker power ratings, and underpowering subs respectively.
 

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 10380
Registered: Dec-03
["clipping signals via underpowering will not damage your sub."

yes, that's an argument that i've unfortunately debunked more than once, lol.
however, i would certainly like qualified electricians/engineers on the site to speak on it from a theoretical perspective.]

ask and ye shall receive.

You are correct that a 500 watt sub will not incur thermal damage from a fully clipping 150 watt amplifier. The math tells us that looking at how much heat you'd generate across the coils based on the power output.
However, here's the trick: What you will do is cause mechanical damage. When a speaker gets a clipped signal, what you get is a driver that travels to it's excursion then stops there as the signal is clipped, instead of coming right back.
As this happens, the speaker usually loses linearity and "cants" the voice coil within the motor structure, scraping the coil windings along teh inside of teh motor, and fraying the coils.
You end up with a frozen sub either way and frayed coils.. so while you're right that you won't get thermal damage from the above example, distortion can still cause mechanical failure in the driver as a result of the clipped amplifier.
My point is just not to assume that because you're not exceeding the thermal limits of the driver, everything is sunshine and flowers.

 

Silver Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 877
Registered: Sep-04
does the fact of running high quality products help against damage? example... say a 1000/1 and a RE MT. both great products. the Mt will definetly want top suck more than 1000-1100 watts the amp can give it but if the gain is set appropriately can this be done safely with these products?
 

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 10397
Registered: Dec-03
speakers don't "sucl" power. they take whatever power is given to them by the amplifiers.
an amplifier just takes the input signal (a small, low voltage waveform provided by the ehad unit) and reconstructs the waveform with more amplitude (power.)
The speaker is simply a magnetic transducer that acts like a piston motor. the more power that you apply (larger amplitude waveform voltage) the more the piston will travel.

think of it like this..
speakers don't "pull" power from an amp.
amplifiers "push" power into the speakers.
 

Silver Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 879
Registered: Sep-04
wow, okay that was my original thought but osmehwere in the middle i got confused and directed the wrong way. so then why does the amp clip... and the main question there... do you think a 1000/1 cud safely run a MT? althought i think im going to wait for teh new XXX instead.
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1254
Registered: Aug-05
"so then why does the amp clip"

b/c the speaker can handle more power than the amp can give it, and still sound good while the amp is at full power(example: 25 volume on your HU)
now when you turn the HU up to 30, the HU sends the new, even larger amplitude waveform voltage, and the speaker can handle even more power, but the amp can't put out any more power, so it clips the signal turning the sine wave into a square wave, and sends the sub DC voltage, in an attempt to increase the power, and the subs VC cant dissipate the heat from DC properly, and the VC's melt.:-)
 

Silver Member
Username: Mikechec9

Http://www.cardomain.c...

Post Number: 990
Registered: May-05
a visual-
so, basically you're taking the triangle wave, and making it taller (increasing in amplitude). but the ceiling isn't high enough (no head room), so the top of the triangle is "cut off." and so when the signal goes up (from left to right), it never reaches the peak of the triangle that was once there, but now is not. hence, the afore mentioned "square wave."
again, just a visual
 

Silver Member
Username: Mikechec9

Http://www.cardomain.c...

Post Number: 991
Registered: May-05
and you're trying to make a speaker move with less power than it takes to move it. and then compensating by overdriving your amp
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1257
Registered: Aug-05
well put mikechec, it was like a powerpoint presentation in my mind. lol
 

Silver Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 882
Registered: Sep-04
thanks guys
 

Silver Member
Username: Mikechec9

Http://www.cardomain.c...

Post Number: 995
Registered: May-05
no doubt.
and thanks for the perspective glass.

"the speaker usually loses linearity and "cants" the voice coil within the motor structure."

that helped a bunch, also.
 

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 10416
Registered: Dec-03
http://www.bcae1.com/2ltlpwr.htm
this explains clipping very well.. with waveform pictures etc.
basically clipping is caused by the power supply not being able to provide adequate voltage rails to reconstruct a clean amplified waveform output.
when there's a lack of current, or the amplifier's power supply is just saturated, the resulting output is a waveform that has the peaks *highest voltage points in the waveform) "clipped off" of the signal. What you get is something that more resembles a square wave at that point, where the flat peaks and troughs are actually DC voltages.
that's what clipping is. a saturated power supply, due to demand or lack of input voltage/current.

the 1000/1 would be ok for a XXX, but weak for an MT.
the MT would be happier with something like an Orion 2500D

that loss of linearity and the resulting distortion is what gets you the common tinsel lead separation issues you see people complain about.
I see that a lot on door speakers run from a head unit. People crank the volume till all you hear is raw distortion, then they wonder why I pull the speakers out of the doors, and the cone is frozen stiff, and the leads are dangling from the terminals like dead noodles. Maybe because they were driving 14 watts of power into a 90 watt speaker, but doing it with 60% distortion.. heh
 

Silver Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 884
Registered: Sep-04
well i currently have a 1000/1 and not enought money for a huge amp. but i might be able to get a 15 MT for a reasonable price to run for a few months before i can get my hands on a new XXX. i was wondering if since the JL amp pushes same power form 1.5-4 ohms... do you think a 1.4 ohm load form a MT will make the amp power down?( because i can only get the D.7 not D1.4).... and i was also told that a MT is REs loudest sub at any given power. example. a MT with a 1000/1 would be louder than a SX with a 1000/1.
 

Gold Member
Username: Carguy

Post Number: 4313
Registered: Nov-04
Trever, your best bet is to measure the sub with DMM. Mine was suppose to be 1.4ohms, but according to my DMM, it's exactly 1ohms.
There's a good chance that .7ohms might be .5ohms, so it'll work out with JL.
 

Gold Member
Username: Carguy

Post Number: 4314
Registered: Nov-04
That's assuming you're getting a quad VC version.
 

Silver Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 886
Registered: Sep-04
nope, it is a dual VC... damnn then i guess i shouldnt try it..
 

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 10434
Registered: Dec-03
don't confuse nominal impedance with DCR.
the DCR will always be lower.
 

Silver Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 889
Registered: Sep-04
man i want some extreme bass (plus i just like testing new <good> things out) before the new XXX line comes out. i wanted to get a Mt for around 350 shipped but its D.7ohm and i have a 1000/1 . maybe i'll get a Audioque HD15 but i dont think i;ll get as good of SQ out of it. any other ideas guys?
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1294
Registered: Aug-05
on this topic, i have a question.

should i run a 12" idmax on my DLS at
2ohms = 870wRMS
or
1ohm = 1200wRMS

i read in another thread that the idmax does great w/ 800wRMS, but would i be better off to go with the extra headroom?
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1299
Registered: Aug-05
bump.
 

Silver Member
Username: Phuktupbasshead

Scottsdale, Arizona United State...

Post Number: 291
Registered: May-05
I ran my IDMAX10 D2v.3 with a 900 watt class D mono... and I ended up having a mechanical problem. The cause of the problem was never decided, but just thought you'd want to know what happened to me.
Also, I heard (a couple of times) that over 1000 watts to an IDMAX is "danger zone" scenario.
???
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1372
Registered: Aug-05
thanks, looks like i'll be running 870 then:-O
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