My english is to bad for write, but I will try.. I read without
problem!!!!

I already finished this Line Array and the sound is very..very good,
fabulous... but, the MID of 4" have a FS at 80hz and the result is a
bad, bad bass response.
http://www.mrweb.com.br/fvm/laf2/

I use active crossover and for bass, I finished this subwoofer:
http://www.mrweb.com.br/fvm/sumario/

But now, I think in build 2 modules for bass response in stereo mode, with this
excelent MID (FS 34hz) to work between range 34hz to 200hz
http://www.mrweb.com.br/fvm/akron/

The BIG question is:

Is possible have "near field" bass response using only 4 drivers in a
tower of 1,80m ??????

Because distance C-to-C will be 60cm and this distance is equal to one
wave at 573hz. 1/2 wave is 286hz....

Thanks,

Renato - Brazil

Thanks,

Renato

I will disagree somewhat with Bill on his answer. Under the proper conditions, I think that the bass array will work well with your line arrays as I explain in my Near Field Line Array white paper at the link. For a 1.8m array height and if you are in an average residence, you likely will be using your bass arrays so that the floor and ceiling will reinforce and extend the effective length of the bass array. My rule of thumb for bass arrays is that the ceiling and floor reinforcement will extend the array by a factor of 3 (think of an array with a ghost image from the ceiling and from the floor). Hence, your array is three times longer that its normal height. The equation that I use for near field extension (distance d is the near/far field transition distance) is

d = 1.5 x f x h2

where f is the frequency in kHz and h is the height in meters. Thus for a h = 1.8 m array its effective length is modified to be 3 x 1.8 = 5.4 m. Thus at 0.100 Khz (100 Hz) the near field distance extends to 4.37 m. You can use the equation to scale to your situation and specific frequency.

Frankly, if I were you in a typical home listening situation, I would use stereo subs (don't have to be bass arrays) below 100 Hz. Then transition to your line arrays above that point.

Jim

• Near Field Line Array White Paper

As far as an array for below 100Hz is concerned I fully agree that for home use other options than an array are usually better, mostly from a cost/function standpoint. The exception to that would be if you managed to find drivers with the right specs at a cost too low to pass up. A dozen eights at $5 each might make a fine alternative to one 15 at $120, for instance. But I wouldn't use a dozen eights at $20 each in lieu of one fifteen at $120.

What if the purpose of the bass array was to dramatically decrease distortion and increase sensitivity of the bass range?

• Bill "I don't use M values in my sub horns" Fitzmaurice Design