Speaker efficiency???

[moves]

Why would the Totem Sttaf (88db) be more efficient than the Totem Forest (87db) that is twice the cost? Is it because the Forest is more powerful?

http://www.totemacoustic.com/products/columns/

 

[jostenmeat]

Why would the Totem Sttaf (88db) be more efficient than the Totem Forest (87db) that is twice the cost? Is it because the Forest is more powerful?

http://www.totemacoustic.com/products/columns/

88 and 87 are darn near the same thing. To paraphrase one of the experts here, designing a speaker is finding one's perfect balance of many compromises. IOW, you can find cheap speakers that can have either high or low sensitivity, and very expensive speakers that have either high or low sensitivity. It's just another one of the decision/compromises to be made.

Also these numbers you list are most likely not for efficiency, but for sensitivity. They are related, but not the same thing in the speaker world. To have the difference be clear to you, I recommend reading this thread starting at this page:

http://forums.audioholics.com/forums/showthread.php?t=66172&page=2

 

[caper26]

I am confused...if something uses the same energy and can make more SPL than another speaker, how is it not more efficient?

 

[TLS Guy]

I am confused...if something uses the same energy and can make more SPL than another speaker, how is it not more efficient?

Because of the way it is measured. If you rate a speaker at 88 db 2.83 Volts 1 watt 1 meter, but one is 8 ohms, largely, but the other is four ohms largely, then the four ohm speaker will draw twice the power from the map to get the same number.

Then you have the issue of dispersion. A good speaker with good wide uniform dispersion, will radiate more acoustic energy into the room. However the measurements are done on axis at a meter. Therefore a speaker with wide and narrow dispersion can have the same sensitivity reading, but the speaker with the good wide dispersion pattern is the more efficient speaker, as it is radiating more acoustic energy into the room for the same input power.

 

[caper26]

thanks on the dispersion (spreading) info...never thought of that, but this part confused me: wide and narrow dispersion and good wide dispersion . As for the ohm ratings, I was assuming we were comparing equal values there. Cheers man.

 

[j_garcia]

It is sensitivity, not efficiency. They are not the same thing.

A 4 Ohm speaker's output is calculated differently as well, so it is not exactly twice the draw, however that is a good rule of thumb to use. I don't recall the exact formula because I don't know where my book is, but the calculation is slightly different due to the difference in impedance.

Those numbers don't tell you 100% of the story either - since impedance varies with frequency so two speakers with the same sensitivity might present very different loads to the amp.

 

[Pyrrho]

Why would the Totem Sttaf (88db) be more efficient than the Totem Forest (87db) that is twice the cost? Is it because the Forest is more powerful?

http://www.totemacoustic.com/products/columns/

It is very often the case that very expensive speakers are less efficient (or less sensitive) than less expensive speakers, because the speaker designers know that if you have the money for very expensive speakers, you are more likely to have the money for more expensive amplification. So if there is something that they want to do that they think will make them sound better, but adversely affects this aspect of the speaker, they often feel more free to do it. But this has nothing to do with the sound quality of the speakers per se, but does have something to do with the amplification needed to drive them. In this case, as has already been stated, the difference is minor and unlikely to matter in virtually all cases.

Again, in itself, this has nothing to do with how good the speaker sounds.