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explain Efficiency (sensitivity)

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=23375
Printed Date: March 28, 2024 at 1:46 PM


Topic: explain Efficiency (sensitivity)

Posted By: dcgc
Subject: explain Efficiency (sensitivity)
Date Posted: December 26, 2003 at 1:43 PM

I got into a argument over efficiency. I tried to explain that the lower the EF the better SQ, the higher the EF the more SPL (at same wattage). I do know that a sub with say 90 dB EF will out perform one with 93 dB at lower htz, But to have the same SPL it would require twice as much power and still have better SQ. Am I wrong or is there a better way to explain this?
For Example: Audiobahn Q15 compared to Eclipse 9115 pro.
I know there is no comparison in the REAL world. But this guy seems to thing that higher EF is better for SQ. I disagree. Oh yeah, what is the EF on the Eclipse 9115 pro?

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2003 Silverado Ext. cab
Kenwood mp922
Kenwood kgc6042a EQ
JL Audio xr650-csi
MB Quart PSC 213
JL Audio 300/4
pair of JL Audio 12w6v2
JL Audio 1000/1



Replies:

Posted By: dcgc
Date Posted: December 26, 2003 at 1:46 PM
*9152* sorry

-------------
2003 Silverado Ext. cab
Kenwood mp922
Kenwood kgc6042a EQ
JL Audio xr650-csi
MB Quart PSC 213
JL Audio 300/4
pair of JL Audio 12w6v2
JL Audio 1000/1




Posted By: forbidden
Date Posted: December 26, 2003 at 5:12 PM

Not necessarily, there are some very good sq speakers that are quite efficient, Klipsch for example. What you are giving is a generalization, of which a lot of poeple will agree. It is generally true that as sq improves, efficency goes down, thus a bigger amp is needed. For the sake of arguement throw sq out the window right now.

(1) if a speaker produces 96 db with 1 watt it is fairly efficient

(2) a similar speaker that produces 90 db with 1 watt is not as efficient.

It will take the second speaker approx double power or 2 watts to produce 93db and approx double again or 4 watt to produce 96db. Keep going with the equation and you can see how power relates to output levels, this however has nothing to do with sq. There are alot of factors that make speakers efficient or inefficient, type and weight of materials are the primary factors. The higher the power handling of the speaker, generally speaking the heavier the materials are going to be, like the cone, dustcap, surround, voice coil and former, tinsel leads, glues, spiders.... A speaker designed for sq is going to be built around the best use of materials to do the necessary job, they are usually really good sounding, but are inefficient due to heavier materials used in construction and need a larger amp. So I will agree with you and not your customer. It's the same thing as having 300 hp in a Mustang and 300hp in a large heavy F350 crewcab longbox 4x4, which one will go faster from a to b, what if we increased the hp in the truck to 400, the car would still kill the truck in a race. Hope this helps.



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Top Secret, I can tell you but then my wife will kill me.




Posted By: eargasm
Date Posted: December 26, 2003 at 8:24 PM

i think forbidden nailed it.

you have the sensitivity and SPL equation right. there is a direct relationship.

but for SQ there is nothing so simple. there's no formula to work out if the SQ is good or bad.



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2001 Ford Fairmont
Alpine DVD, screen,
5.1surround processor,
5ch Class-T amp, TV tuner
and centre channel.
Focal 3way Utopia splits.
VDO navigation. Stinger cap.
Soundstream Exact subs.




Posted By: Durwood
Date Posted: December 26, 2003 at 11:35 PM

Yep - Also, don't forget that the *type* of speaker makes a huge difference, not just the materials.  The reason that the Klipschorn home speakers are efficient as hell (106 dB/W-m) is that they're horn-loaded compression drivers.  Horn drivers for car use, such as those by Image Dynamics, are also very efficient, and no one can seriously claim they're lacking for sound quality.

Scott Gardner






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