A question on speaker sensitivity

[imassarano]

Hi everyone,

My first post on this forum.

I'm planning to use full range drivers that are specified at 45Hz - 20kHz with Fs 45Hz, and I plan to use them full range with their obvious advantages.

Since they have Xmax 5mm and 30Watts RMS power handling with only moderate sensitivity of 88dB 1W/1m, I would like to try employing 3 of them in an array. By wiring them series/parallel, i.e. both series and parallel, it would substantially increase both the power handling and sensitivity for much greater SPLs with only a moderate decrease in system impedance making for an easy load for an amplifier.

I just wanted to know what the reultant speaker's system sensitivity would be. I believe there is a formula for it.

[woody]

Now how are you going to do that ? You could do that with 4 drivers and your
sensitivity would be 6db higher.

[AndrewT]

Just use three 40W to 50W chipamps. Each one dedicated to a driver.
That will give you +9dB due to the 3times extra power you are converting to sound.
Over a narrow range of frequencies you can get upto another +9dB of bass SPL.

[Cal Weldon]

Hi imassarano,

Is that a typo? Did you mean 4 drivers as woody suggests?

In theory you get the 6 dB extra but there is some cancellation so count on 4-5.

[imassarano]

Thanks for your replies.

I figured on 3 drivers per speaker, as each has a min impedance of a little under 9ohm, and 3 wired series/parallel, as I understand it would give a handy load for a range of amplifiers. Is that "do-able"?

[Cal Weldon]

As 3 in parallel yes. That would offer around 3 ohms which may or may not be suitable for your amp. You can't do a series parallel and get equal power to the drivers, you need 4 for that.

[tuxedocivic]

What's wrong with two drivers in parallel, and then one in series with those. That would be about 13.5 ohms though. The one in series would see more power I suppose. I would go with 3 in parallel if your amp can take it.

Those are a strange impedance driver.

[chris661]

... or two drivers in series, one in parallel with those?

Gives one louder driver, that you'd probably sit in the middle of the array. I'm sure line arrays have been done with volume contouring before.

[mashaffer]

Can you provide full specifications? You may have better results by using a rear loaded horn enclosure with a single driver rather than having to deal with the comb filtering effects of an array. Another possibility is to use two of them in a 1.5 arrangement where one driver is run full range and the other uses a low pass filter so that it only reproduces the bass. This would give some help in the low end where the driver is probably lacking the most and the comb filtering would not be a problem.

[bbggg]

Originally Posted by imassarano

I plan to use them full range with their obvious advantages

I'm afraid full range electrodynamic drivers have no sonic advantages, obvious or otherwise, and stacking more than one of them together will make even those properties of theirs that some people perceive as advantages vanish.