How important is efficiency ratings when choosiing a sub?

[toxic 10+ year member]

I am building a SQ active setup for my truck. Using an Eclipse 7200II deck and starting to look for amps and subs now.

I only have room for 2 10's.

I have a Kicker CV10 in another truck with a rf amp and it sounds pretty good.

Looking at the eff ratings, it is in the mid 80's...

For every 3 dB increase I know you have to double the power. So why not get the highest rating you can find??

The tweets and mids I will be using are 92 and 93 at 1w/1m.

Are JBL GTO 1014d's any good? They have an effeiciency rating of 91 at 1w/1m.

I am NOT looking for a rap , hip hop earthshaking or SPL setup. Just good clean bass and the more efficiecnt woofer the less needed for an amp???

Correct??

Click to read more...

 

[JimJ 5,000+ posts]

So why not get the highest rating you can find??

Because often times, enclosure sizes get prohibitively large to maintain LFE, at least in a vehicle.

12V amplifiers are cheap enough, relatively speaking, that efficiency would be pretty low on my list of priorities. At home, where enclosures can get much larger and amplifiers much more expensive, that's a different story...

 

[audioholic 5,000+ posts]

Efficiency ratings mean almost nothing in this situation. Did you know they take that efficiency measurement while playing a 1khz note? How often do people play their subs as high as 1khz? Never.

And, even if it did give an accurate assessment of a sub's efficiency, many times you actually want a sub with low efficiency, thanks to Hoffman's Iron Law.

Pretty much ignore it totally.

 

[joshualittle]

I'm also doing a sound quality setup using the eclipse cd 7200 mkii deck. I decided to go with arc audio amps and hertz mille ml 3000 subs because of their high efficiency. They also make a hx line that's cheaper and still very efficient. If your interested I can get you in contact with someone who sells both at just above cost.

 

[toxic 10+ year member]

Thanks for the replies! I need all the help I can get. I live in a pretty rural area and the closest good stereo shop is over an hour away.

I have narrowed the mainstage to 3 brands. Hertz, Focal, or Dynaudio.

Not looking to spend a fortune just for the sake of spending money, just want the best quality sound I can afford.

Audiophile, what should I look for when picking out subs that I have never heard in person?

Thanks again guys. I will check out the Hertz Mille subs and do some searching and reading on Hoffman's Law??

I appreciate the advice!

 

[joshualittle]

Yea car audio mag did an in depth review on the hertz mille ml 3000 12", just google it and u should beable to find it. it got a 47/50 in sound quality rating by the magazine.

 

[joshualittle]

http://www.caraudiomag.com/reviews/caep_0712_hertz_mille_ml3000/index.html. Here is the review on the hertz mille ml 3000.

 

[audioholic 5,000+ posts]

Hoffman's Iron Law: small enclosure, good low frequency extension, high efficiency.... HIL states that you may have 2 of those 3 characteristics.

So this tells us that if you want a system that has good low freq extension while still using a small enclosure, efficiency must be low.

 

[joshualittle]

http://www.caraudiomag.com/testreports/0403cae_jlaudio_12w6v2_car_audio_subwoofer/index.html then there's the jl audio 12 w6, it got voted the best subwoofer tested by the magazine.

 

[joshualittle]

http://shop.mega-watt.co.uk/hertz-mille-ml2500-87-p.asp. Here's the specs on the 10" hertz mille ml 2500.

 

[Rashaddd 5,000+ posts]

Hoffman's Iron Law: small enclosure, good low frequency extension, high efficiency.... HIL states that you may have 2 of those 3 characteristics.
So this tells us that if you want a system that has good low freq extension while still using a small enclosure, efficiency must be low.

But is that really so much describing a law of drivers? Or is that more referring to the box, or subwoofer system as a whole

Is not a small box designed for low frequency extension inherently inefficient? Simply because the low frequencies require lots of air displacement, so quite obviously the less air the subwoofer is working with, the poorer it will be at producing these low frequencies

 

[audioholic 5,000+ posts]

But is that really so much describing a law of drivers? Or is that more referring to the box, or subwoofer system as a whole
Is not a small box designed for low frequency extension inherently inefficient? Simply because the low frequencies require lots of air displacement, so quite obviously the less air the subwoofer is working with, the poorer it will be at producing these low frequencies

It describes the system, the speaker + enclosure. Yes, a small enclosure displaying good low end will require lots of power because you have a small 'air spring' to pressurize and good low end means lots of excursion (small box, less air molecules, more compression required per molecule). This means the system will require alot of power to perform well... inefficient.
And yes you bring up another valid point. Actual speaker efficiency means little for subwoofers, as the over all system efficiency (speaker + enclosure) is what you actually hear. And enclosure size can/will be altered to account for any unwanted efficiency issues with the driver itself, again to give you the final system performance you want.

Efficiency means alot more for mids, as they are almost always mounted IB where they rely entirely on their own suspension for cone control. There is no enclosure efficiency or cone dampening to consider.

 

[Rashaddd 5,000+ posts]

It describes the system, the speaker + enclosure. Yes, a small enclosure displaying good low end will require lots of power because you have a small 'air spring' to pressurize and good low end means lots of excursion (small box, less air molecules, more compression required per molecule). This means the system will require alot of power to perform well... inefficient.
And yes you bring up another valid point. Actual speaker efficiency means little for subwoofers, as the over all system efficiency (speaker + enclosure) is what you actually hear. And enclosure size can/will be altered to account for any unwanted efficiency issues with the driver itself, again to give you the final system performance you want.

Efficiency means alot more for mids, as they are almost always mounted IB where they rely entirely on their own suspension for cone control. There is no enclosure efficiency or cone dampening to consider.

Agreed.