Im going to add this here on increasing efficiency by only adding more drivers while applying the same input power for each case whether it is just 1 driver or 8 drivers. I wrote this below at OUR in a thread on motors. So what Im going to say in this thread about speaker efficiency may also apply to other drivers like motors.

This is what I wrote over there.....

Ive been saying something about this for some time now. The example is with speakers/subwoofers. Here it is...

When we apply 1w input to a speaker and we measure spl in decibels(db) from a distance 1 meter away from the speaker, then that measurement is the Sensitivity spec of the speaker.

So if a speaker is say found in the specifications as 90db@1w Sensitivity, then that should be what we read on the meter..

Now an odd phenomenon is that if we now set up 2 of the same speaker together, and we still only input 1 total watt to the system, we will increase 3db to a new total sensitivity level of 93db@1w. Now double the speakers again. 4 speakers, 1 watt total, 1/4w each speaker, we again increase 3db. So now our system is 96db@1w....

And we can double them till you cant fit anymore, every time you double the number of drivers and divide 1w total among the larger array, we gain 3db.

Where does that gain come from?(http://www.overunityresearch.com/Smileys/Alive/huh.gif)?? Its not free certainly. You have to purchase twice as many drivers to jump to the next level.. Where does it end? Does it? (http://www.overunityresearch.com/Smileys/Alive/huh.gif)

Ive said this before and maybe not here, this drawing below as shown in above texts, series connection or parallel, there may be a similar gain by doubling the motors. Shaft to shaft would be most eff vs belts and pulleys. Has anyone really done this test with 2 identical motors before? Seems like a waste of time I know and many others agree before even trying. But... considering the real gain of just doubling the numbers of speaker drivers driven at the same total input of 1w in each case, by doubling we increase output, acoustic power measured in watts.

Here it is.. We increase the efficiency of the system by only increasing the numbers of drivers while still maintaining the same 1w input for each case. So why is it so impossible for that to be a probability for 2 motors driving the same train vs 1 motor? +3db?? That is just a noticeable difference in level of sound we can detect. From 1 speaker to 4 speakers at 1w total in, it is a very noticeable difference of +6db. Add 4 more speakers and divide the 1 watt among all 8 speakers and you are at +9db. 10db for us sounds like a doubling of volume level. All gained by simply adding drivers and not increasing the input. Where does that gain come from???

Like I said above. Nobody has probably ever tried to specifically measure the eff of 2 ganged motors against 1 motor. Maybe it is just a noticeable gain, like 3db??? Well what about 4 ganged motors vs 1 motor. Do we get a very noticeable eff gain like 6db from speakers would be a very noticeable gain?? Who would think to check that specifically, and even then to take it next level of 4 motors after not seeing much from just 2 motors compared to 1? For the first thoughts of coming up with it would be extinguished by preconceived notions that nahh, could never happen.. Gain??? nahh, not wasting my time. lol But the speakers are doing just that.

So if anyone is game on this then that would be the test to try. Measure the eff of 1 motor vs 4 ganged(very precisely as to not cause any added binding that would hurt the test)

Id go the same route as the speakers. No matter series or parallel connections of the additional motors, the input needs to remain at a particular watt input. 10w or 100w what ever, but the total has to be the same for 1 motor being tested and 4 ganged to be tested and drive a consistent load with each config to see if 4 at 1w tot can drive the same load better than 1 motor at 1w in. If someone only has 2 motors to compare to 1, then the accuracy of the test needs to be great as there may only be a 'noticeable increase in eff and if there is a slight increase that cannot be ignored then the 4 gang would need to be tested to be very sure that there is a gain from just 1 motor alone. Instead of a 3db increase with 2 motors it should emulate a 6db increase with 4 motors vs 1. And then we will know. Put it to bed, or ride that eff gain wave.

Mags

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Here is an example of what Im telling you..

The green trace is 1 subwoofer at 1w total in

The yellow trace is 32 subwoofers at 1w total in.

WinIsd speaker box software free. A lot of big guys in the business will tell you they use it all the time. Simple and gets the job done right.

Check it. Recheck it. Its all true. Eff gain using more drivers at the same power in.

Mags

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Confused about the gain part?

1 speaker. 90db@1w

2w in +3db 93db

4w in +3db 96db

8w in +3db 99db

Double the watts in and increase 3db

1 speaker. 90db@1w

2 speakers 1w each 2w total +6db 96db

4 speakers 1w each 4w total +6db 102db

8 speakers 1w each 8w total +6db 108db

Double speakers and double total watts in for an increase of 6db

So double the watts in gives 3db increase. Likewise decrease watts in by half, reduce output by 3db

Here is the link. If we double the speakers and the total power in, can we say that we got the 6db increase just from doubling the power in? Well we only get 3db increase by doubling the power in only. But we get 6db more if we double the total power in AND double the drivers. So the addition of more drivers increases efficiency all on its own.

Yup ist all true.. Been under my nose for 25years in the car audio industry. Back in the 90s guys would do 32 8in subs and run 100w total and beat guys with 2 15s running a kw. Because there is efficiency in numbers.

Mags