Why is it so hard to get loud?

[Buck 5,000+ posts]

If you have one sub that does 135 on a meter and you add a second sub in the same identical setup why wont you hit 270db? (Even though I know it is physically impossible.) But hopefully you guys will get what i mean by that. What factors come into play when trying to gain a couple of DB's on the meter at a time over 145.XX....Just wondering what peoples opinions are.

The measurement for decibels is a logarithmic function. It's not addition/subtraction. Energy used to create more sound increases exponentially as dB's increase.

 

[Buck 5,000+ posts]

Hell, even I can agree with that. With basic knowledge, you can get some pretty good sounding designs. Not the best, but definitely satisfying to most who do not notice the difference in sound-and that's perfectly fine also. Is this going to hurt my business saying that? LOL

Hrm, I know someone who did this...

 

[Linkz 10+ year member]

As other have said db is a logarithmic function. Being so a doubling of volume will gain only 3db. A doubling in intensity will require 10db.

 

[Buck 5,000+ posts]

Perceived loudness and SPL levels also may vary some.

 

[Moble Enclosurs 10+ year member]

Perceived loudness and SPL levels also may vary some.

Very true. It is frequency dependant as well. Perceptual hearing response makes a difference on the actual response calculated. This is why people state theory and actual vary as well. Also why a flat response may not be desired by some. If we could take the measured response of each individual, a much more accurate one can be put into play, but as of now, its close enough.

 

[Team TH (Donny) 10+ year member]

Yes, weird enough two guys out of our team were both hitting the same db's a good while back at 152.5 all though one didn't sound like it should be hitting 152.5 and the other was very brutal it was painful to sit in there for long. Mind you they were both hitting ~47 Hz. Weird that they were dead on db's with each other, but the intensity of each were incredibly different.

 

[TheUnderFighter 10+ year member]

Yes, weird enough two guys out of our team were both hitting the same db's a good while back at 152.5 all though one didn't sound like it should be hitting 152.5 and the other was very brutal it was painful to sit in there for long. Mind you they were both hitting ~47 Hz. Weird that they were dead on db's with each other, but the intensity of each were incredibly different.

That's very strange.... how does that happen?

 

[Team TH (Donny) 10+ year member]

I personally don't know I would assume the box differences? Or perhaps because one was using a DC 9k amp and the other a Sundown 3500. Heck Moble Enclosures might be able to add some input about why that happened..

 

[SPLaudio 5,000+ posts]

to hit good numbers its trial and error. if you have been in the biz for a long time you have alot more experience and know what to try and what will work.

if ur going for #'s you want to tune 4-6dbs lower than cabin gain( test that freq with a meter and a sealed box).

you almost NEVER gain up to the 3dbs max by adding another sub reason being ur changing the cabin vol and restricting some air flow. doubleing the power or sub displacement normally gives you 1.5-2.5dbs of gain.

make a box with a adjustable port but post up pix of ur cabin and i will be more than happy to help you get louder...

 

[Germ305 10+ year member]

to hit good numbers its trial and error. if you have been in the biz for a long time you have alot more experience and know what to try and what will work.
if ur going for #'s you want to tune 4-6dbs lower than cabin gain( test that freq with a meter and a sealed box).

you almost NEVER gain up to the 3dbs max by adding another sub reason being ur changing the cabin vol and restricting some air flow. doubleing the power or sub displacement normally gives you 1.5-2.5dbs of gain.

make a box with a adjustable port but post up pix of ur cabin and i will be more than happy to help you get louder...

I will keep that in mind when the holiday season comes around....But this was just a general question for the members of CA...and there have been some great answers. Reason i asked is because i know some people here compete and i thought it was a good question to ask. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[wickedwitt 10+ year member]

alright well mobile knocked this one into Steven hawkins front yard and surreal was talking weight lifting lol just playing surreal..
Sound Decibels aren't 1 is 1 and 2 is 2 times whatever made 1.. its not that simple.. every 3 dbs is a doubling of sound if I remember correctly.. been a while since I looked at it.. In a PERFECT world doubling power and cone area.. Basically doubling your current setup would gain you 3 dbs.. Now then that is in a perfect world where all variables lined up perfectly..

Sound Pressure Wiki

Sound Wiki

Sound Level Meter

These are not the end all, be all authorities on this subject; but they are a wonderful place to start grasping some solid knowledge on how sound works.

EDIT: Almost forgot-

Power and loudness in the real world

Perceived "loudness" varies logarithmically with output power (other inversely proportionate factors are; frequency, number and material of objects through which the sound waves must travel, as well as distance between source and receiver) a given change in output power produces a much smaller change in perceived loudness. Consequently it is useful and accurate to express perceived loudness in the logarithmic decibel (dB) scale.

An increase/decrease of 3 dB corresponds to a doubling/halving of power. The sensitivity of loudspeakers,rather than merely the often-quoted power-handling capacity, is important. Many high quality domestic speakers have a sensitivity of 84 dB for 1 W at 1 meter, but professional speakers can have a figure of 90 dB for 1 W or even 100 dB (especially for some large-coned woofers). I.E., An '84 dB' source "speaker" would require a 400-watt amplifier to produce the same audio energy as a '90 dB' source being driven by a 100-watt amplifier, or a '100 dB' source being driven by a 9.92 watt amplifier. This does not mean a bigger speaker can produce more sound with less overall power. Just that a larger speaker can typically handle more initial power and so requires less amplification to achieve the same high level of output. This means using a speaker with a higher dB rating can be more advantageous as very high power amplifiers become impractical.

A better measure of the 'power' of a system is therefore a plot of maximum loudness before clipping of the amplifier and loudspeaker combined, in dB SPL, at the listening position intended, over the audible frequency spectrum. A good system should be capable of generating higher sound levels below 100 Hz before clipping, as the human ear is less sensitive to low frequencies, as indicated by Equal-loudness contours.

Taken From- Audio Power

Generic Rules of Thumb- 3db= 2x the power, 3x the output 6db=4x the power, 9x the output and 9db gain= 8x the power, 27x the output. (Of sound level, not your system wattage)