Help choosing sub

[talnlnky]

Originally Posted by Alien Mantis

You contradict what many manufacturers are recommending to consumers.

I read plenty of information from the likes of Alpine, JL, Pioneer, etc... that claim you are just flat out WRONG.

You CAN underpower a sub.
Whether or not it will damage it... I don't know.

A sub is designed for a certain "power-range".
If you give it too much power, it can smoke it.
If you give it too little power, you won't have any performance/response out of it.
High power subs NEED power to push them, and keep them tight, especially at higher volumes.
If we could use a 50watt amp on our pair of Alpine Type-X 12" subs, EVERYONE would be doing it!
Who wants to spend $400 on a 1,500watt RMS amp if I can push my sub setup with 50watts ?!?!?

Subs like the JL W7 and Alpine Type-X REQUIRE lots of power to push them, and keep the response clean and tight, especially at higher volume levels. Nobody buys a JL W7 to play SOFTLY.
People spend big bucks on this stuff because they want people to hear them coming down the street.
PERIOD.

My Alpine Type-R 10" sub has a recommended power range of 200-500watts RMS. And 200 watts would be the bare MINIMUM. It probably sounds pretty weak with only 200watts trying to push it.
( and most likely, not as tight sounding, either )

Putting 50watts on a JL W7 probably wouldn't even make the cone move.

Subs that have high efficiency ratings can play louder with LESS power, but they still need SOME power.
Subs, ( especially GOOD subs ), have a higher power rating, and a lower efficiency rating because they are made for high power.
They NEED high power.

SQcomp is right though, all systems must have all the gains set correctly.
You cannot use an amp gain knob as a "volume" knob.
And all your components must MATCH each other.
Don't buy a 2,000watt RMS sub, and put a 400watt amp on it.
Don't buy a 500watt RMS max sub, and hook it to a 1,500 watt RMS amp.
You are just wasting money.

You CAN run a larger amp on a weaker sub, you just need to turn the gain down on the amp.
The question is, WHY would you do this?

My sub is rated at 500watts RMS max, and I have it hooked to an amp that puts out 400watts RMS.
My gain is set around the 10 o`clock position, my preamp outs are around 2.2v.
My sub sounds very nice, and my sub and amp run cool.
My amp barely gets warm, even after blasting it for an hour straight.
( my sub amp has a 2ohm load on it, at 4ohm load... it never even got warm. )

Maybe I am totally wrong, but I read articles and specs, and I see people with opinions that contradict what I read sometimes.
I know you guys have lots of experience, and I am not challenging your experience. I am just confused by what you just said about a 10 watt amp powering a 12" subwoofer.

I NEVER heard of anything like that.

Don't blindly trust the information coming from the person that has something to gain from you.

Is there such thing as too small of an amp? No
Do I recommend buying a bigger amp than you need? Kinda, for people who know audio I do, for people who can't set gains & eq levels properly I don't.
Will clipping hurt a sub? No, but the extra heat that it causes could toast your coil if you have too much total power going to the sub... furthermore, for a fully clipped signal (square signal) you'll have 20% less voice coil cooling due to the decrease in cone movement... so if you had a 1000w sub... now it can only take 800watts.... if you had a 800watt amp and are now clipping it... you could be pushing close to 1600rms. if you had a 300watt amp... you are still below the 800rms mark even with a fully clipped signal.

Manufacturers say things for two reasons...
1) to make money
2) to teach the ignorant, without getting technical - therefore, a lot of what they say isn't exactly true, but for the masses, it'll generally steer them in the right direction... however, the whole issue with amp size/clipping... they're in it for money. Clipping is a problem that stems out of GREED (for more spl) or ignorance (in not knowing how to set gains & eq levels). Neither will be fixed or even bandaged with simply buying a larger amp.. in fact, your chances of cooking your sub if you have a larger amp are significantly higher, because you won't have to clip as much to reach the thermal limits of the sub... Clipping is a nasty sounding distortion too... its rare that people have a 100% clipped signal.... but its also not uncommon for people to have a clippless signal.




Oh yeah... I think I saw something about size of cone being better or worse depending on the music you listen to.... cone size has NO EFFECT on how tight or sloppy a sub sounds. That is all determined by the Le of the voice coil, the design of the box, and the group delay & frequency response peaks. 8's can play as low as 15's, tho they usually aren't designed too, 15's can be just as tight as 8's... tho people usually don't design their installs to sound that way.