What does a speakers sensitivity mean?

[Mancave]

I read someone who said don't buy speakers that were less than 89db. How come? I read another guy say he had to just turn up the volume and had to have enough power in his receiver to do it. So what does the sensitivity mean? Is it true about the 89db?

 

[lsiberian]

Sensitivity is how likely a speaker is to cry.

On a serious note it is the amount of SPL produced by 1 watt at 1 meter by the speaker. In home theater applications you are fine with any speaker normally, but in commercial applications you need high sensitivity to fill the space.

 

[monkish54]

I read someone who said don't buy speakers that were less than 89db. How come?

Because the more power you put into your speakers, the more heat gets created. Voice coil heat has several poor effects.

So what does the sensitivity mean?

Sensitivity is the SPL level (measured in db) a speaker will play at 1 meter when presented with 2.83 volts.

An 8 ohm load will produce 1 watt at 2.83 volts
A 4 ohm load will produce 2 watts at 2.83 volts.

When looking at the specifications of a loudspeaker, make sure to check whether sensitivity is listed as 2.83 volts or 1 watt.

2.83 volts into a 4 ohm load will be 2 watts. This means a 4 ohm speaker rated at 87db @ 2.83V/1M is 84db @ 1watt/1M

Is it true about the 89db?

It's all in how you look at it, and how loudly you listen.

It is the amount of SPL produced by 1 watt at 1 meter by the speaker.

That's actually efficiency, not sensitivity.

Sensitivity is 2.83 volts/1 meter

In home theater applications you are fine with any speaker normally

I disagree. Reference level for movies has peaks of up to 115db!!

If my 8ohm speaker is rated as, say, 87db sensitive I would need 1,859 watts to get them to 115db at 8 feet. That INCLUDES the summation of two speakers! If it didn't, the figure would be literally double.

Not to mention power compression, inductance change, system QTC change, crossover frequency change! Heat/watts are NOT your friend. The less power needed to reach the desired SPL the better. This is within reason of course. My speakers are 84.5 db/watt!

 

[lsiberian]

Because the more power you put into your speakers, the more heat gets created. Voice coil heat has several poor effects.
Sensitivity is the SPL level (measured in db) a speaker will play at 1 meter when presented with 2.83 volts.

An 8 ohm load will produce 1 watt at 2.83 volts
A 4 ohm load will produce 2 watts at 2.83 volts.

When looking at the specifications of a loudspeaker, make sure to check whether sensitivity is listed as 2.83 volts or 1 watt.

2.83 volts into a 4 ohm load will be 2 watts. This means a 4 ohm speaker rated at 87db @ 2.83V/1M is 84db @ 1watt/1M

It's all in how you look at it, and how loudly you listen.
that's actually efficiency, not sensitivity.

Sensitivity is 2.83 volts/1 meter
I disagree. Reference level for movies has peaks of up to 115db!!

If my 8ohm speaker is rated as, say, 87db sensitive I would need 1,859 watts to get them to 115db at 8 feet. That INCLUDES the summation of two speakers! If it didn't, the figure would be literally double.

Not to mention power compression, inductance change, system QTC change, crossover frequency change! Heat/watts are NOT your friend. The less power needed to reach the desired SPL the better. This is within reason of course. My speakers are 84.5 db/watt!

Being Mr. Technicality(I've seen sensitivity use the 1watt measure before) and a hypocrite in one post, but as we both know higher sensitivity generally means less BSC. Which typically means a lower quality speaker. Of course your JTRs and horns don't fall pray to this, but most people listen at 60 db in their home. 90db would be the reference peak in that case. For the Record THX reference peak is 105 db not 115 db. You'd need JTRs or horns to hit 115. Unless of course THX change their standard on me again which they are known for doing. Still you will get sound reinforcement from the first order reflection so the number isn't entirely accurate for a given room situation. It's best IMO to select on sound quality than entirely off sensitivity.

 

[monkish54]

Being Mr. Technicality(I've seen sensitivity use the 1watt measure before) and a hypocrite in one post

I laughed super hard at this because it's true! I've seen it too, but technically 1 watt is efficiency.

but as we both know higher sensitivity generally means less BSC.

I would never recommend a speaker that trades BSC for sensitivity!


That would be very bad!

Unless of course THX change their standard on me again which they are known for doing.

Nope, you are safe! It's 115db peaks for LFE and 105db for main channels. I like to be cautious. 105db peaks for movies doesn't sound loud enough. Not to mention people listen to movies, generally, at very loud volumes. Music is 100-105db with a good recording (85 average + 15db dynamic range), but movies have much more dynamic range.

It's best IMO to select on sound quality than entirely off sensitivity.

Agreed!

There is no one parameter I have found that I would use for a purchasing decision. There are many considerations! Hell, my speakers are pretty damn low on the sensitivity meter!

 

[KEW]

I read someone who said don't buy speakers that were less than 89db. How come? I read another guy say he had to just turn up the volume and had to have enough power in his receiver to do it. So what does the sensitivity mean? Is it true about the 89db?

There are trade-offs. Many of the most sensitive speakers employ horns which not everyone likes.
IMHO, it is more important that you like the sound of your speakers than whether they are especially sensitive.
Make sure they play loud enough for you in a room at least as big as the one you plan to use them in.
Frankly, I wouldn't get too worried about sensitivity ratings because most B&M speakers just pick a number their marketing department likes!
I cannot remember anyone posting that they regretted buying speakers which were low sensitivity; though some have come to the realization they needed a better amp to handle impedance drops.

 

[lsiberian]

I laughed super hard at this because it's true! I've seen it too, but technically 1 watt is efficiency.
I would never recommend a speaker that trades BSC for sensitivity! That would be very bad!

I remember a poster that was looking at 94 db speakers that were like bookshelves one time if there isn't a horn involved that's normally a dead giveaway especially if the speaker is cheap. Those are white van kind of numbers. 84 definitely means you have a great crossover.

 

[Swerd]

I read someone who said don't buy speakers that were less than 89db. How come? I read another guy say he had to just turn up the volume and had to have enough power in his receiver to do it. So what does the sensitivity mean? Is it true about the 89db?

As mentioned above, sensitivity is how loud a speaker gets when its fed a signal amplified to 2.83 volts, measured with a microphone or SPL meter 1 meter away. If a speaker is nominally an 8 ohm load, 2.83 volts becomes 1 watt, and for 4 ohms it becomes 2 watts.

A speaker's efficiency is how well it transforms electrical energy into acoustic or mechanical energy. All speakers with magnets, voice coils, cones and spiders are inefficient, and much of the electrical energy is lost as heat. These two terms are related, but sensitivity directly refers to how loud a speaker gets under standard defined conditions.

You should take that comment about 89 dB with a large grain of salt for several reasons:

1. There is a very wide variation in how speaker makers measure and rate sensitivity. So comparisons of numbers will get you nowhere.
2. Some speaker makers report sensitivity honestly or even conservatively. Others, not so much. So comparisons of numbers will get you nowhere.
3. There is a large amount of exaggeration and misinformation about speakers and audio available over the internet. In particular, it is now fashionable to talk about how loud and sensitive your speakers should be. If you believe this talk, you will come to the conclusion that loud public address (PA) speakers made for large auditoriums or sports arenas are the only solution for home theater. This is clearly wrong.

 

[markw]

I'm a simple guy. I like simple analogies.

It's kinda like a car getting a certain miles per gallon. The higher the number, the less gas you need to go so far.

But, with a speaker, the higher the number, the less watts you need to reach a certain loudness.

Remember, watts are cheap. Buy a speaker based on it's sound, not it's sensitivity number.

 

[Swerd]

It's kinda like a car getting a certain miles per gallon. The higher the number, the less gas you need to go so far.

But, with a speaker, the higher the number, the less watts you need to reach a certain loudness.

Remember, watts are cheap. Buy a speaker based on it's sound, not it's sensitivity number.

Watts are cheap and good sounding full-range speakers are expensive.

Watts are getting cheaper, and gasoline is getting more expensive.

 

[avnetguy]

Is there something behind the 89db?

If you take some average numbers (guessing here) for room size, typical delivered watts from an mid-level up AVR (100w), listening position of 8ft, and 89db 1w/1m speakers you do reach about 105db SPL.

Steve

 

[monkish54]

That's actually efficiency, not sensitivity.

Sensitivity is 2.83 volts/1 meter

Being Mr. Technicality(I've seen sensitivity use the 1watt measure before)

A friend of mine has brought it to my attention that I was being foolish.

Sensitivity can be measured using watts or volts.

I apologize for incorrectly correcting you lsiberian!

Have this

as a peace offering!