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Speaker sensitivity vs SQ

My first thread at AG.

Millercarbon continues to bleat on about the benefits of high sensitivity speakers in not requiring big amplifier watts.
After all, it's true big amplifiers cost big money.  If there were no other factors, he would of course be quite right.

So there must be other factors.  Why don't all speaker manufacturers build exclusively high sensitivity speakers?
In a simple world it ought to be a no-brainer for them to maximise their sales revenue by appealing to a wider market.

But many don't.  And in their specs most are prepared to over-estimate the sensitivity of their speakers, by up to 3-4dB in many cases, in order to encourage purchasers.  Why do they do it?

There must be a problem.  The one that comes to mind is sound quality.  It may be that high sensitivity speakers have inherently poorer sound quality than low sensitivity speakers.  It may be they are more difficult to engineer for high SQ.  There may be aspects of SQ they don't do well.

So what is it please?

128x128clearthinker
glupson
7,842 posts
 
"A voice coil fan!! Gotta run patent it!"

Not exactly that, but this is another voice coil with a rotating device...

Rotary woofer - Wikipedia
bdp24's avatar
bdp24
9,686 posts
 
Excellent @glubson. From the fertile mind of Bruce Thigpen, the Eminent Technology TRW-17 Rotary Subwoofer, for the bottom octave (20-40Hz) down (fed enough power, flat to 1Hz!).
ctsooner
2,480 posts
 
Guys, it's simply not true to make a statement that a higher sensitivity speaker is more costly to make.  Drivers, cabinet material, R&D, spikes, connectors, wire, glues, finishes.... and of course how many points dealers get to sell them if selling through conventional means will determine costs, not sensitivity.


clearthinker's avatar
clearthinker OP
1,582 posts
 
Hi ctsooner.

Others have said that higher sensitivity speakers have to be larger in order to transduce low frequencies at the correct levels.  Also that driver manufacturing tolerances are tighter.  Both these increase costs.

But if that's not correct then you must go back to my original post and tell me why all manufacturers don't build high sensitivity speakers, rather than only a small minority.
atmasphere's avatar
atmasphere
11,749 posts
 
Guys, it's simply not true to make a statement that a higher sensitivity speaker is more costly to make.  Drivers, cabinet material, R&D, spikes, connectors, wire, glues, finishes.... and of course how many points dealers get to sell them
Let's be clear about one thing: Sensitivity isn't the same thing as Efficiency and it really is the latter which is the focus of this thread. You can build a high sensitivity speaker by simply taking a number of low efficiency drivers and putting them in parallel. Cheap and high sensitivity, but its efficiency will remain low. High Efficiency cannot be achieved cheaply for the simple fact that there is a much higher degree of precision needed in the construction of the driver's motor.

The difference between Sensitivity and Efficiency: The former is 2.83Volts at one meter. The latter is 1 watt 1 meter. If the speaker is 8 ohms the two are the same. If we take four 8 ohm drivers that are 87dB and put them in parallel, the load is now 2 ohms. The sensitivity is increased by 6dB; 93dB doesn't sound too bad. But that is 2.83volts into 2 ohms; when you do the math that is 4 watts. If you put 1 watt into that same array you'll still get 87dB. A higher efficiency driver that can make 98dB with 1 watt and is 8 ohms is a different beast altogether. This describes the 15" drivers in my speakers at home and they cost $2000.00 each.


You can find 15" drivers that cost $200.00. I'd be very interested to learn of a 15" with the same 22Hz free air resonance and 150 watt power handling that cost $200, or even $600.00. Have at it! But I think you'll find that such simply does not exist.
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