# Is subwoofer sensitivity important?



## alex912005 (Jan 8, 2014)

How important or relevant is this subwoofer parameter? Does it realy apply to the real output of a sub?

Let's take into consideration the following subwoofers:

Ascendant Audio Mayhem 18 (2500wrms)- 94 db @ 1w/1m
Fi Team 18 (4000wrms)- 90 db @ 1w/1m (probably measured the same way since they are made by the same company)

Does this mean that the AA Mayhem would be 4db louder than the Fi at the same power?


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## fcarpio (Apr 29, 2008)

Short answer: Yes.

If a speaker has high sensitivity its ouput volume will be greater than another speaker with less sensitivity, that is assuminmg all other things are equal. Off course, there is more to it but it requires some math to explain and I am not prepared to do that.


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## ZAKOH (Nov 26, 2010)

alex912005 said:


> How important or relevant is this subwoofer parameter? Does it realy apply to the real output of a sub?
> 
> Let's take into consideration the following subwoofers:
> 
> ...



Manufacturer sensitivity specs are utter BS. I am specially wary of all numbers above 89dbs. I would say they're not important. If you're interested in _estimating_ the subwoofer sensitivity before buying one, load its T/S parameters into a recent version of WinISD and it will estimate the sensitivity for you.


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## ZAKOH (Nov 26, 2010)

fcarpio said:


> Short answer: Yes.


Yes, it's important, but the sensitivity specs reported by something like +70% of all vendors, high end and low end, are garbage. Because of it, you can't trust any of them.


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## captainscarlett (Mar 15, 2011)

Not really! Look at the likes of Sundown Subs. Most of them are in the low 80's, some go into the 70's i believe, and they seem to do OK. I would look to your enclosure more than worrying about sensitivity figures of a particular sub. 

A free air sub as described by PWK, is a near soundless air-pump.


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## edzyy (Aug 18, 2011)

No

It's measured at 1khz


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## JoshHefnerX (Jun 13, 2008)

If you have enough p_ower to reach xmax it's not very important. 

Josh


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## schmiddr2 (Aug 10, 2009)

Might help: Sensitivity Spec in Car Audio : Hoffmans Iron Law Discussion - Sundown Technical - SSA Car Audio Forum


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## alex912005 (Jan 8, 2014)

schmiddr2 said:


> Might help: Sensitivity Spec in Car Audio : Hoffmans Iron Law Discussion - Sundown Technical - SSA Car Audio Forum


I read that post and it kind of says the opposite of what I thought. So sensitivity is not important on subwoofers, only on higher frequency drivers.

So should I go for the higher powered sub? Or any other suggestions for subs in this price range?


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## captainscarlett (Mar 15, 2011)

alex912005 said:


> So should I go for the higher powered sub? Or any other suggestions for subs in this price range?


Again RMS figures are a guide but I wouldn't take it as ROT. One can put many times the power on a sub within a given passband. For example, I put my tiny Hybrid Audio I6SW 6.5" subwoofer (then rated at 60 watts) on a Ground Zero rated at 1,100 watts @ 4 ohms, and the little Hybrid took it without complaint. Not saying you should do this as a rule, but just an example. 

Many SPL competitors put huge power into subs rated at around 500, 1k, 2k, albeit sometime for short bursts. But in reality, I'm sure such competition are are also blasting on their daily drive. 

The other *HUGE* consideration is the Enclosure. Many claim that small drivers can't hit low for example. I respectfully disagree. 


















So whatever sub you have, make sure the enclosure is optimised for what you want.


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## alex912005 (Jan 8, 2014)

Ok, thanks for all the input.


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## qwertydude (Dec 22, 2008)

edzyy said:


> No
> 
> It's measured at 1khz


This belief somehow perpetuates itself on this forum. Subwoofer manufacturers most definitely do not measure their efficiency at 1khz. For one thing model the output on WinISD of a well known subwoofer with complete thiele small parameters. Something like a JBL, to make it obvious take the MS12.

http://data.manualslib.com/pdf3/52/...?78f4411b5d640765812d49bad699ca0d&take=binary

Clearly in the manual this is rated at 87 db 1w/1m based on two graphs of output in a test enclosure. They most definitely pick the peak because if you average the 0 and 45 degree measurement peak, at about 300 hz, it gives right around 87 db. Specifically at 1000 hz the output drops do a miserable 77 db.

The specification generally measured at 1khz isn't sensitivity, it's inductance.

It is true with more sensitive subwoofers that are built with low inductance and lightweight cone assemblies, the peak will be at a higher frequency which generally isn't conducive to loud and deep bass.

On the other hand less sensitive subwoofers with heavier beefier cone assemblies and longer coils, due to needing to achieve high excursion at high power, mean sensitivity will be lower along with the efficiency peak.

This is also why "low efficiency" subs can still sound loud and most definitely get low, but if you ever can put a high efficiency subwoofer in a large enough enclosure, it can carry its natural efficiency down into the lower registers and then you'd truly be amazed at what a high efficiency subwoofer can achieve. I'm talking rattling your entire house on just a couple hundred watts something impossible with a low efficiency sub no matter what box you put it in. With the caveat being you'll likely need a 15-20 cubic feet of cabinet for one or two big 15" PA style subs. But it is a thing to experience it, amazing punch, responsive bass that can dig as deep as the ocean AND kick you in the chest like a mule. Only an efficient design subwoofer can achieve that type of bass output. A lightweight designed subwoofer can definitely be made to output deep bass with a large well tuned cabinet. A big heavy ground pounder can never output upper bass with any authority period.


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