Incorrect or correct? That is the question.

[zumbo]

I made a statement in a thread about speakers. I was showing a member how one of his choices had a higher sensitivity, and better frequency response. I made the statement that the one speaker that had a 2db higher sensitivity rating, would be almost twice as loud at the same level of input power. I also made the statement that the said speaker would be an easier load for a receiver.

It is my understanding that my statements are correct. I have been harassed by a member slamming me in PM's about my above statement. I have apologized for being offensive, but to no avail.

What Klipsch has to say about it:

"Q. How much amplifier/receiver power do I need?

A. The output of a speaker (measured in decibels (dB)) for a given amount of amplifier power is termed its efficiency. Speakers with high efficiency will require less amplifier power to produce a given sound pressure level. Live music and movie soundtracks have peak levels as high as 120 dB. To attain just a 3 dB increase in volume, an amplifier's power must be doubled regardless what the speaker efficiency. Therefore, the amount of amplifier power needed if you wish to attain the sound pressure levels of a live orchestra or a large explosion in a movie is greatly dependent on the efficiency of your speakers. Here is a chart that shows two different speakers, one with 88 dB efficiency (common) and one with 100 dB efficiency, and the amplifier power need to produce given sound pressure levels:



The above charts show that the typical speaker with a sensitivity of 88 dB requires 1024 watts just to get to 118 dB! A more efficient speaker (example here is our KLF-30) requires just 64 watts to hit those levels of live music and Home Theatre. Therefore, the amount of amplifier power that a person needs is determined by the efficiency of the speaker that person is using plus the desired dB levels he or she wants to be able to produce. Other variables which impact the choice of amp power are the size of the listening room, the absorption characteristics of the wall and floor surface materials and the distance between listener and speakers. In a smaller room and with high efficiency speakers, 50 watts may be enough to provide full dynamic range. In a large room with low efficiency speakers, even 500 watts may not be enough. Higher speaker efficiency always helps deliver the most from whatever power you choose."




So, here it is. Let me have it boys.

 

[mtrycrafts]

... I made the statement that the one speaker that had a 2db higher sensitivity rating, would be almost twice as loud at the same level of input power.
So, here it is. Let me have it boys.

Here you go. I think you may have confused 3 dB change in power as needing 2x of power with loudness. Not the same.

For 2x perceived loudness, you need 6dB - 10dB spl change. I say this because some research supports one and some supports the other.

Speakers sensitivity refers to loudness but, it needs that power change to make it happen, or in this case, a change in sensitivity.
Does this help?

 

[zumbo]

Here you go. I think you may have confused 3 dB change in power as needing 2x of power with loudness. Not the same.

For 2x perceived loudness, you need 6dB - 10dB spl change. I say this because some research supports one and some supports the other.

Speakers sensitivity refers to loudness but, it needs that power change to make it happen, or in this case, a change in sensitivity.
Does this help?

So a speaker with a 3db higher rating would not be twice as loud as one 3db less with the same input power? It seems that is what Klipsh is saying, and that is the way I have understood it for years.

 

[Sheep]

Didn't you do something similar to this like... a year ago?

SheepStar

 

[mtrycrafts]

So a speaker with a 3db higher rating would not be twice as loud as one 3db less with the same input power?

Correct. You will save 1/2 the power of use 2x the power but audibly and subjectively it will not be twice as loud. Try it at home and see if it sounds twice as loud to you when you increase the volume 3 clicks or 3 units on the indicator.
Try it at low levels, then try it with a 10 unit change.

 

[zumbo]

Correct. You will save 1/2 the power of use 2x the power but audibly and subjectively it will not be twice as loud. Try it at home and see if it sounds twice as loud to you when you increase the volume 3 clicks or 3 units on the indicator.
Try it at low levels, then try it with a 10 unit change.

I can go along with that, but it is half as hard on the receiver regardless. Correct?

 

[zumbo]

Didn't you do something similar to this like... a year ago?

SheepStar

Nope. That was about a 4ohm speaker compared to a 8ohm speaker. Good memory though.

EDIT: I guess this is somewhat similar.

 

[mtrycrafts]

I can go along with that, but it is half as hard on the receiver regardless. Correct?

Well, yes, if you are increasing the sensitivity by 3 dB you have twice as much power available in essence. Or, if you are decreasing it, it is twice as hard
For example: if you listen at 90 dB with a speaker what is 90 db sensitive, at 1 m, it will be 1 watts of power, but with a 93 dB speaker, you need 1/2 watt for 90 dB spl.

 

[zumbo]

Well, yes, if you are increasing the sensitivity by 3 dB you have twice as much power available in essence. Or, if you are decreasing it, it is twice as hard
For example: if you listen at 90 dB with a speaker what is 90 db sensitive, at 1 m, it will be 1 watts of power, but with a 93 dB speaker, you need 1/2 watt for 90 dB spl.

So lets take perceived out of it.

Is it a measurable fact that a speaker with a 3db higher sensitivity rating would be twice as loud(with the same input power), and will require half the power to produce the same loudness?

 

[OttoMatic]

Here you go. I think you may have confused 3 dB change in power as needing 2x of power with loudness. Not the same.

For 2x perceived loudness, you need 6dB - 10dB spl change. I say this because some research supports one and some supports the other.

Speakers sensitivity refers to loudness but, it needs that power change to make it happen, or in this case, a change in sensitivity.
Does this help?

This is absolutely correct.

 

[OttoMatic]

So lets take perceived out of it.

Why? It's exactly what we're talking about. When you say that a speaker is "twice as loud," I think that you're referring to an end user's perception.

Is it a measurable fact that a speaker with a 3db higher sensitivity rating would be twice as loud(with the same input power), and will require half the power to produce the same loudness?

A speaker with a 3 dB higher sensitivity will be 3 dB louder as measured on an SPL meter. I believe that the measured energy will be "double" from a mathematical point of view. But to a user, a 3 dB increase isn't that much (i.e., not double). As suggested, just sit down and do it at home. Play music, TV, pink noise, whatever and listen for a while (go for something without tons of dynamic range). Then turn it up by 3 dB per your receiver or pre/pro's volume knob. Does it sound twice as loud? No. Drop it back down to where you started, get reacclimated, and bump it up by 7 or 10 dB and see if you think it's double there. As noted above, it's very subjective, so it just depends on the user.

Yes, you doubled the required amplifier power when you did that 3 dB increase, but the loudness that you hear, that you perceive, didn't double. Yes, the SPL measured energy doubled from a mathematical/engineering point of view, but I don't think that's what we're talking about.

If you have one speaker that's 3 dB more sensitive than another then, yes, the more sensitive speaker will require half the amplifier power to generate the same SPL output.

For the record, I think I'm the guy that's been "slamming" zumbo in PMs. In general, my tone has been the same as this post, and I've been trying to explain these differences using the same descriptions I've used here.

 

[MDS]

If you have one speaker that's 3 dB more sensitive than another then, yes, the more sensitive speaker will require half the amplifier power to generate the same SPL output.

That's what I interpreted the original question to be and that is accurate but everyone seems to be jumping on him about perceived loudness levels.

- Double the power is a 3 dB change. 3 dB is perceived to be noticeably louder but just a bit.

- Double the perceived loudness is generally accepted to be +10 dB, which would be 10x times the power, not double. As usual there are exceptions and it depends on the content but for some pure tones one perceives the loudness to be double with as little as 6 dB change in output. Nobody can 'prove' that the loudness has doubled so these numbers were arrived at via listening tests and are just general rules of thumb.

 

[OttoMatic]

That's what I interpreted the original question to be and that is accurate but everyone seems to be jumping on him about perceived loudness levels.

That's cool, but here's what I was thinking. From the OP:

I made the statement that the one speaker that had a 2db higher sensitivity rating, would be almost twice as loud at the same level of input power.

I agree that one speaker will be 2 dB louder with the same amplifier power input. But I don't think it'll be twice as loud with that same input. That's it. That's the whole argument.

I don't think it'll be twice as loud with a 3 dB increase either, even though the amplifier's power output has indeed doubled.

 

[MDS]

Yeah, saying twice as 'loud' is not accurate but his actual description described twice the power, which is accurate.

I think it is all straight now...

 

[mtrycrafts]

So lets take perceived out of it.

Is it a measurable fact that a speaker with a 3db higher sensitivity rating would be twice as loud(with the same input power), and will require half the power to produce the same loudness?

Well, let me confuse you just a bit. The sound pressures created by the speaker with that 3 dB sensitivity increase is indeed 2x more pressure but that is not what your brains will tell you, it is logarithmic. So, I cannot say it is twice as loud because loudness is what we perceive. And yes, will require half the power to create the same loudness.

there are a few terms here sound pressures, loudness perception that you have to sort out in the mind first before you will grip it

 

[zumbo]

None of this is about perception. It is about fact. My wording may not have been the best, but I never used the term perception.

While what someone perceives to be so(usually BS), can't hold a candle to cold hard facts. A receiver/amp will be working half as hard driving the speaker with a 3db higher sensitivity rating. That is all this is about. The db level(I termed as loudness) will be (3db) twice as loud.

So, to me, 2db is almost. If it's not almost, it's 2db higher none the less.

A member was building an extreme budget system. In a budget system, power will be lacking. The best option for a budget system with low power is to use the speaker with the higher sensitivity. Granted, this spec has nothing to do with SQ, as we all know. But, SQ may not need to be the most important factor in a budget system. It's a budget system.

 

[fmw]

Or to put it another way, a 3db change in sound pressure level would be a large one in the under 10 db area but a fairly small one in the 100 db area. Nevertheless, it is still 3db - linear change. In order to increase the SPL by 3db requires an approximate doubling of amplifier power - a geometric change.

 

[OttoMatic]

The db level(I termed as loudness) will be (3db) twice as loud.

OK, zumbo. You're right back where you started. Saying that a 3 dB increase is "twice as loud" is ambiguous at best, and confusing at worst.

Say what you want, think what you want.

Good luck.

 

[zumbo]

OK, zumbo. You're right back where you started. Saying that a 3 dB increase is "twice as loud" is ambiguous at best, and confusing at worst.

Say what you want, think what you want.

Good luck.

I didn't make the rule that a 3db increase would require 2x the power.

By "twice as loud", I have clearly described this as being a measurable 3db difference. Again, I didn't make the rule.

This is not about human hearing. What someone perceives is (BS). DBT prove this over and over.

A db scale on a volume knob is not the same thing. There is no set standard for the db scale of a receiver/pre-pro. So, this is not about the db scale on a receiver/pre-pro. This is about a db scale on a SPL meter in a lab, or room.

Klipsch quote again:
The typical speaker with a sensitivity of 88 dB requires 1024 watts just to get to 118 dB! A more efficient speaker (example here is our KLF-30) requires just 64 watts to hit those levels of live music and Home Theatre. Therefore, the amount of amplifier power that a person needs is determined by the efficiency of the speaker that person is using plus the desired dB levels he or she wants to be able to produce. Other variables which impact the choice of amp power are the size of the listening room, the absorption characteristics of the wall and floor surface materials and the distance between listener and speakers. In a smaller room and with high efficiency speakers, 50 watts may be enough to provide full dynamic range. In a large room with low efficiency speakers, even 500 watts may not be enough. Higher speaker efficiency always helps deliver the most from whatever power you choose.

 

[OttoMatic]

A db scale on a volume knob is not the same thing. There is no set standard for the db scale of a receiver/pre-pro. So, this is not about the db scale on a receiver/pre-pro. This is about a db scale on a SPL meter in a lab.

If you turn up by 2 dB on the volume knob, you should realize a 2 dB measured gain on an SPL meter. It doesn't have to be in a lab; I can do it in my living room, and so can you!