What does a 5dB increase in sensitivity mean?

[Defcon]

So I've read a few things which make this confusing -

- speaker sensitivity is not same as efficiency
- sensitivity can be measured in 2 ways - 1W/1m and 2.83v/1m

I'm asking because I bought a new speaker which has a 5dB higher sensitivity (95 vs 90) compared to my old one, and this was a main reason as its a center channel. Yet it doesn't play any louder.

 

[TheWarrior]

So you bought a new center channel instead of turning up the center channel on the AVR?

 

[tyhjaarpa]

Speaker sensitivity is pretty much the same as efficiency as far a I know.

What those ratings meas is how many db it will produce 1m away from speakers with 1watt of power.

Did you run auto calibration from your receiver when you did the setup? If so, your receiver most likely matches your center with rest of speakers. In receiver settings you can adjust the speakers levels so you can have center channel louder than your front speakers for example.

To get best possible front stage sound you should get center channel from same line as your front speakers are for better match. If you have random center compared to your front speakers it will most likely stand out.

 

[fuzz092888]

http://www.audioholics.com/loudspeaker-design/loudspeaker-sensitivity

Loudspeaker Sensitivity: a measure of Sound Pressure Level (SPL) at a specified distance for a specified input signal. This is usually specified for a loudspeaker in a non-reverberant environment, in dB SPL and referenced to 1 meter on the reference axis with an input of 2.83 volts RMS, typically at one or more specified frequencies (often 300, 400, 500, 600Hz or the average of these). Sensitivity should always be accompanied by an impedance specification.

Loudspeaker Impedance: is the sum of DC resistance and complex AC reactance comprising inductance and capacitance, the value of which changes with frequency.

Editorial Note about SPL Change:
A 3 dB change in sound level is just nicely noticeable as a change in loudness. It requires 10dB power change to halve or double perceived loudness at mid/high frequencies and about 6dB at low frequencies.

“Efficiency” is NOT the same thing as “Sensitivity”

Speaker engineers use the term “sensitivity” because it is technically more precise definition of how loud a speaker will play when driven by an input signal of at a specified voltage level. “Efficiency” is usually a more colloquial term used by consumers, to informally describe how much power a speaker needs to achieve a desired loudness level: “Oh, your speakers a real power hogs. They’re not very efficient.” From a technical standpoint, “efficiency” is defined as the sound power output divided by the electrical power input—but that’s not how consumers use the word. So rather than try to turn laypeople into engineers, we’ll just concentrate on sensitivity.

The reason for quoting sensitivity rather than efficiency is that the true efficiency of a speaker varies wildly with frequency because of its impedance variation. The efficiency quote would be fairly meaningless, so loudspeaker engineers measure and refer to “sensitivity” instead.

 

[Defcon]

So you bought a new center channel instead of turning up the center channel on the AVR?

Not sure where you get that. Current LCR are the same speakers, after calibration center was set at same level as LR and I turned it up +4dB.


I wanted to try out the center speaker as it had great reviews on its own and was hoping it'd be louder too.

 

[its phillip]

What speakers are you talking about? You need actual measurements to compare the two. Just because a speaker's spec page boasts a sensitivity of 97 dB @ 2.83V/1m doesn't mean it's true.

 

[TLS Guy]

Speaker sensitivity is pretty much the same as efficiency as far a I know.

What those ratings meas is how many db it will produce 1m away from speakers with 1watt of power.

Did you run auto calibration from your receiver when you did the setup? If so, your receiver most likely matches your center with rest of speakers. In receiver settings you can adjust the speakers levels so you can have center channel louder than your front speakers for example.

To get best possible front stage sound you should get center channel from same line as your front speakers are for better match. If you have random center compared to your front speakers it will most likely stand out.

Not quite.

Sensitivity is measured on axis. It tells you little about the energy radiated into the room, unless you combine it with the dispersion pattern.

So a lousy speaker that beams like crazy may have a higher, or the same sensitivity as a speaker that has a good dispersion pattern. The latter speaker will radiate much more energy into the room, and is therefore the more efficient speaker.

So if the op finds that his speaker is no louder, with the same receiver settings, then he likely bought a very speaker with a barrow dispersion pattern.

The other issue is how the sensitivity is measured. If the sensitivity is quoted a 1 watt one meter then on a power basis they are equivalent. However if one speaker is 8 ohm and the other four ohm then the four ohm speaker will play 3 db louder. On the other hand if the sensitivity is quoted a 2.83 volts 1 meter then the four ohm speaker will show as 3db higher in sensitivity, but take twice the power.

 

[Defcon]

The 2 speakers in question are -

old: Infinity Primus P163 - used vertically as center channel
new: BIC FH6-LCR

BIC is 95dB vs 90dB, when I swap speakers without changing anything, its not really louder, and it should be if specs are accurate, correct?

 

[shadyJ]

There is no way the BIC is really 95 dB sensitive. Two mid level 6" woofers and a horn-loaded aluminum tweeter can not do that, unless that measurement was taken in some unusual condition, like 1/8 space. The I would bet the Infinity and BIC speakers are pretty close in terms of sensitivity.

 

[TheWarrior]

Not sure where you get that. Current LCR are the same speakers, after calibration center was set at same level as LR and I turned it up +4dB.


I wanted to try out the center speaker as it had great reviews on its own and was hoping it'd be louder too.

"I'm asking because I bought a new speaker which has a 5dB higher sensitivity (95 vs 90) compared to my old one, and this was a main reason as its a center channel. Yet it doesn't play any louder."

The Infinity Primus series is very well respected in it's price bracket. I would use caution with BIC, their designs do not impress by their specifications/design.

 

[TLS Guy]

The 2 speakers in question are -

old: Infinity Primus P163 - used vertically as center channel
new: BIC FH6-LCR

BIC is 95dB vs 90dB, when I swap speakers without changing anything, its not really louder, and it should be if specs are accurate, correct?

Well the specs are not correct. I have done some careful checking.

Here is the problem.

I can find measurements of the primus series.

Now both speakers are specked by the manufacturers at 1 watt one meter sensitivity scale

However all the Primus series speakers are actually 4 ohm speakers not 8 as specified.

This speaker is virtually identical to your P163.

The speaker has pretty decent dispersion.

I can not find an impedance curve for the BIC. But assume it is 8 ohm then as measured by a sensitivity of 2.83 volts 1 meter, then the BIC would be 95 db sens, and the infinity 93 db, but the infinity would pull twice as much power from the receiver as the infinity.

Now add the fact that the BIC has a Horn tweeter and one that is likely to have much more on axis power and less dispersion it is easy to see how the speakers would have identical loudness with sensitivities quoted at 90 and 95 db 1 watt 1 meter.

The bottom line is that loudspeaker manufacturers specs mean virtually nothing unless you dig a lot more.

 

[Defcon]

I might return the BIC, it was local store buy so its not a problem. I really wanted to upgrade the center channel for < $150, any other options in this price range?

 

[tyhjaarpa]

I might return the BIC, it was local store buy so its not a problem. I really wanted to upgrade the center channel for < $150, any other options in this price range?

It is best to match front stage. So getting better center would go with better fronts as well if you now have them matched.

 

[TLS Guy]

I might return the BIC, it was local store buy so its not a problem. I really wanted to upgrade the center channel for < $150, any other options in this price range?

What is the problem with your center speaker now? At this time everything is matched. From the look of the measurements on the PS2 it looks as if that Primus range are good speakers fro the money.

I think if you really want to upgrade your sound then you need a much bigger budget.

 

[Defcon]

There is no problem I really wanted to explore higher sensitivity speakers, I have to listen at -20dB on my AVR (Yamaha) and it seems rather high. Since center gets the most use in HT and tv watching it seemed worth exploring, and the FH6 has very good reviews.

 

[tyhjaarpa]

There is no problem I really wanted to explore higher sensitivity speakers, I have to listen at -20dB on my AVR (Yamaha) and it seems rather high. Since center gets the most use in HT and tv watching it seemed worth exploring, and the FH6 has very good reviews.

For best sound you reall want matched front speakers. Also the volume you have in your receiver means nothing as long as you can get to volume level you like to listen at.