Power vs Decibels

[ThxOne Premium Member]

I am trying to make sense of it all. I can't seem to get the answers I am looking for or perhaps I am just asking the wrong questions. Basically I am trying to find out what the output of each speaker should be in relation to the next type of speaker. Like say if my midrange outputs 100db of sound... should my tweeter also put out 100db of sound... my sub as well? You follow what I am asking? Should all speakers outputs be the same (before EQing). Below are 4 speakers, 3 of which I have. My US Acoustics amp is 100 x 4 rms @ 4ohms. This should be more than enough power to get the DB's past 110db per individual speaker. By adding a second speaker also getting the same amount of power as the first speaker will add +3db of output. Can anyone verify that I did this right. Every +3db takes double the power to achieve. I think a reasonable goal is 115db - 120db... which for a normal stereo is crazy loud.

The first DB listed for each speaker is its rated sensitivity by the manufacturer. Looking at the power vs DB's for each speaker makes sense now why you'd want to keep them withing a few DB's sensitivity of each other (mids vs tweeters). As an example the Dayton mids would be a better match to the Dayton tweeters than my Silverflutes. Cabin gain should help the sub out with the lack of power... at least a little bit... right?

Dayton Ti Tweet 40w rms / 80w max with correct crossover
Sens. in DB vs Wattage
95.5db = 1w
98.5db = 2w
101.5db = 4w
104.5db = 8w
107.5db = 16w
110.5db = 32w
113.5db = 64w
116.5db = 128w
119.5db = 256w

Silverflute 6.5" Midwoofer 80w rms / max unknown - say 160w
Sens. in DB vs Wattage
91.5db = 1w
94.5db = 2w
97.5db = 4w
100.5db = 8w
103.5db = 16w
106.5db = 32w
109.5db = 64w
112.5db = 128w
115.5db = 256w

Dayton Audio PS65LP-4 40w rms / 80w max
Sens. in DB vs Wattage
99db = 1w
102db = 2w
105db = 4w
108db = 8w
111db = 16w
114db = 32w
117db = 64w
120db = 128w
123db = 256w

Punch P3D4 10" 500w rms / 1000w max
Sens. in DB vs Wattage
82db = 1w
85db = 2w
88db = 4w
91db = 8w
94db = 16w
97db = 32w
100db = 64w
103db = 128w
106db = 256w
109db = 512w
112db = 1024w
115db = 2048w

Click to read more...

 

[THATpurpleKUSH 5,000+ posts]

Sensitivity does not translate to literal output with a given wattage. Its more of a reference point.

 

[Jeffdachef 5,000+ posts]

The goal is to get the output you want while maintaining low thd and high clarity/detail. Unless you are doing a loud mids and highs competition, all of this is pointless.

 

[ThxOne Premium Member]

The goal is to get the output you want while maintaining low thd and high clarity/detail. Unless you are doing a loud mids and highs competition, all of this is pointless.

That IS pretty much the goal... how loud literally or to that "reference point with a given wattage" will the speakers get without breaking up. I know the numbers will be different than just the straight forward math given above. Like distance, direct and reflected sound, the number of drivers, mounting locations and so on all affect the output of the drivers. My main question was how loud should each speaker be in relation to the next type of driver.

If I tune my mids and the max undistorted output they give me is 100db do I then bring my tweeters up to 100db to blend with them or are they supposed to be at more or less output than the mids?

SkizerR suggested this - "Try a curve that is flat from 20hz to 40hz, then from 40hz, drops 18db to 200hz. Flat from 200hz to 2.5khz, then from 2.5khz to 20khz, maybe a 5 db drop. afterwards, you might need to cut a bit in the 2.5-4k area" So, ignoring the sub at this point, the goal is a flat run of mids up to the tweeter and the tweeters should have less output in the range of up to -5db?

If an IASCA judge is sitting in my car I want them to say "It may not be the best sounding stereo but output is correct". I have no reference personally so I need a reference. Everyone says my DSP is capable of so much more and I want to get more out of it. Yes, knowing approximately how loud speakers could get with specific wattage input will help tremendously.

What I am going to do is set my mids with a -5db reference tone and stop. I will then break out the MIC and I will use uncorrelated PINK noise and measure the mids then flatten the output with the EQ in the DSP then stop. I will then, using the same pink noise, bring up the tweeters to up to -5db of the flattened mids curve? Then EQ the Tweets? Blending the sub in is easier to do by ear, then eq as well.

 

[THATpurpleKUSH 5,000+ posts]

Fun facts about sensitivity:

It's measured at 1khz in a free air environment with 1w at a distance of 1 meter away on axis.

Its just a reference point.

If you are concerned about fine tuning you should prob invest in a Term Lab RTA or whatever gadget they use now.

 

[ThxOne Premium Member]

Fun facts about sensitivity:

It's measured at 1khz in a free air environment with 1w at a distance of 1 meter away on axis.

Its just a reference point.

If you are concerned about fine tuning you should prob invest in a Term Lab RTA or whatever gadget they use now.

I already know how sensitivity is measured. I have a MIC and Room EQ Wizard so fine tuning isn't the issue nor the question.

 

[nauc 10+ year member]

110dbs mids/highs?

you gonna ruin your hearing real quick lol

 

[ThxOne Premium Member]

You guys are going to make me pull my hair out!

I don't want to listen to it full tilt all the time.

My hearing is 46 years old... it works but it ain't 21 anymore.

I am guessing you guys don't know either. I guess it is time to ask professionals in the audio world.

 

[YourNameHere 10+ year member]

research "equal loudness contour" it might help ya out some

 

[dragon.breath 10+ year member]

The charts you posted don’t work in the real world. Period.
Their is the difference in mounting and sound deadening.
The size of the cabin of the car.
The differences between power and sensitivity ratings of different manufacturers.
You also are not factoring in power compression.

You are trying to use elementary school math on college level calculus problems.(And the calculus is still just a educated guess)

 

[ThxOne Premium Member]

The charts you posted don’t work in the real world. Period.
Their is the difference in mounting and sound deadening.
The size of the cabin of the car.
The differences between power and sensitivity ratings of different manufacturers.
You also are not factoring in power compression.

You are trying to use elementary school math on college level calculus problems.(And the calculus is still just a educated guess)

I know this. I mentioned some of this in post #4. It's is ok, I am having some back and forth with a professional audio engineer at a recording studio in NY. So far, very eye opening.

JRsmoothee, I have actually been studying those curves for several weeks. By far the most helpful info. I thank you.

 

[Jeffdachef 5,000+ posts]

You guys are going to make me pull my hair out!

I don't want to listen to it full tilt all the time.

My hearing is 46 years old... it works but it ain't 21 anymore.

I am guessing you guys don't know either. I guess it is time to ask professionals in the audio world.

you are far overthinking this. You can do this all by ear. As long as you have a proper blend you are fine. You can notice slight shifts in the sound stage with more tweeter or less tweeter. Tune in the way where your staging is at proper height and width. No one will know what DB level that would be and its a moot point to even bring it up. This is when your ears need to take over in the tuning.

 

[ThxOne Premium Member]

I am hoping that by the end of my research I will be able to understand the way the original music is intended to sound. Once this is known, it is easier to reproduce it in a car environment. I won't have to act like I know how to do it, I WILL know how to do it and maybe even be able to explain it in layman's terms.

The DB's Mr. Chef are more for a reference for me. Again, how loud is an SQ car? I have no idea what IASCA expects or deems a normal sound level. I would like to know. All these things help.

 

[ThxOne Premium Member]

And just like that... the beginnings of the answer. The 90db Reference - The Fletcher-Munson Curve - The resonant frequency of the human ear canal... Now we are getting somewhere.

 

[dragon.breath 10+ year member]

You still aren’t getting it. I don’t care who you are and if you are a “professional “ or not. You are going to have to actually install some equipment in your car and listen to it. And then start to adjust the things that are wrong.

I am going to give you an example. About 10 years ago I knew 2 guys in a local mustang car club. Both had the same model car. One guy had a full aftermarket stereo installed by a local shop. The other guy heard it and loved the way it sounded. So he went to the same shop and bought the exact same equipment and had installed by the same people. The second car was 1.6db louder on the meter and the eq curve was very different between the two cars. The only difference between the two cars was the color and one car had fabric seats and the other one had leather seats.