Subs and the Truth about them!!!!!!!!

 

Bronze Member
Username: Jamesdunn

Anniston, Alabama US

Post Number: 42
Registered: Sep-04
What makes a sub a good sub?

What will kill a sub and why?

Whats the diff. if the true RMS rating and the Thermal RMS rating?

What does the box have to do with killing a sub?

Is a amp with the RMS rating with 12.5volts beter than an amp with the RMS rating with 13.5 volts of power going to it?

Can any1 help me understand these thing?
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2158
Registered: May-04
Lots of things make a good sub, build quality is #1. What makes a good sub solely depends on what it's intended to do. SQ subs will exhibit low moving mass, great control over the sub, linearity at all volume levels, low resonance, and a smooth impedance curve. SPL subs will have extremely strong motors, huge excursion and surface area, and will usually be designed to work well in SPL type enclosures (bandpass, vented, etc.) Also, they will be designed to handle huge power bursts.

Overpowering a sub will kill a sub. You can overpower a sub with less power than required. Power handling is based on the enclosure used, the thermal handling of the voice coils, and the amount of power (watts) applied. If you have too much power and run high power for long periods of time, you will overheat the voice coils, and they will fail. When you push any amp past it's capabilities, it will "clip", resulting in a square wave, and that holds the sub in the same place for longer than normal. The cooling of the voice coil is dependant on cone motion, and when it stays in place for too long, heat will build up and won't cool as much b/c the sub isn't moving like it should. That's why an amp that puts out less power than the sub can take can still damage the sub.

RMS is a thermal rating. Many manufacturers make subs that only handle the RMS required to reach full excursion in the intended box, but RMS rating is always thermal. You don't necessarily need the specified RMS power to reach full excursion, and you also may not get to full excursion with the RMS if your box is too small.

The box is what controls the cone of a sub. If the box is too large, it has less control on the sub and it will allow the sub to have more excursion, meaning that if too much power is applied, the sub will try to move past it's limits, resulting in mechanical damage. In ported enclosures, anywhere above tuning, the cone actually is controlled more than it would be in a sealed enclosure. But, if you run a signal that is lower than the tuned frequency of a port, the sub will "unload", not seeing the box, and will have no control, and if given too much power, the sub will have extreme excursion and will possibly have mechanical damage.

12.5V assures you the amount of power more so than 13.5V, because your electrical system (if the charging system is up to par) should always be above 12.5V. Different amp companies rate amps differently, some drastically underrate their products, and their products will produce much more power than they're rated for (especially high end american companies). Low end companies will overrate products, and likely will list a "peak power" that will only be obtained by a lightning bolt striking it or the placement of God's hand upon it. IMO, it's better to rate an amp at 12.5V than something higher b/c, given that the ratings are accurate, you're assured that power level more often.



 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 410
Registered: Sep-04
lol, "lightning bolt"

you read that same article on that vette build

-Fishy :P
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2169
Registered: May-04
You should have heard how Glasswolf put it. Here ya go:
" "peak" or "max" output, sometimes called "PMPO" and so forth can be up to four times the RMS power output. How they actually derive this number is a tightly held secret though, and apparently involves a crystal ball, an elbow-length rubber glove, and a very dark smelly orifice.
That's strictly rumor though so don't quote me on that."
 

New member
Username: Cleveland

Post Number: 3
Registered: Oct-04
you want a good sub trust me ?
if you can aford it ?
dd digital dynamics 18inch x2 runing of 4 amps made my pants move out side the car ?
idmax havent herd them but look spifo for sq
cewl bro
titanem ecilps all right they got cooling things fore the voice coil ?........
 

Silver Member
Username: Invain

Michigan United States

Post Number: 240
Registered: Aug-04
Dude, do you have any idea what your saying?
 

Bronze Member
Username: Skema

Manch, NH US

Post Number: 44
Registered: Aug-04
lol
 

Anonymous
 
this is grmmtically incrrect sentence with kwestion mafrk at end ?....
 

Juggalo Jeff
Unregistered guest
yea dick likes dick my brother
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