Any 8” line arrays ?

norman bates

norman bates

Member
Joined 2003
I’ve been wrestling on dispersion vs output of an 8” driver.

I dispersion gets pretty tight on an 8”, unless you have a lot of hf climb then listen off axis (maybe w8-1772).

But let’s take an flattish 8” (w8-2145).

I find it has a sweet spot of 1 head at 7’, maybe 2 heads when shoulder to shoulder at 12’.

So a few of them should not interfere with each other much.

Maybe 4 or 6 of them in a vertical line array.

That would give a bit of bass further from it, less distortion (less cone motion), especially for those who boost the bass (me).

It keeps the whole time alignment thing together too.........

Yes, still narrow width dispersion, but maybe better sound 15’ away than 1 driver struggling....... Especially when turning it up a bit.


Thoughts ?
Ideas ?
 
Shure vocal master VA300-S? Saw a set on Reverb for $150, but you had to live in WI..
 

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I understand your way of thinking, but that's not how it works.
Due to beaming, small drivers, with small c-to-c will have combing starting at higher frequencies, like 6kHz.
A LA of 8" drivers will start combing at something like 2kHz... That's a lot of frequencies being affected and it will be horrible.
 
Will it ?

At 2khz, the driver dispersion is narrowing, more and more the higher you go.

7’ away the sweet spot is about the size of a head.
That’s about it.

If you put another driver below it, I bet at 7’, there would be no high frequency loss (say 5khz).

Even my 4x3” needs to be a bit aimed (combing).
 
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Jim Griffin wrote Design Guidelines for Practical Near Field Line Arrays

The basic conclusion is you want small diameter drivers. He used the SB Acoustics SB65WBAC25-4 2.5" Full Range in his personal arrays. The difficulty with arrays is the high frequency range because you want to keep them within one wavelength center to center. I turned to panels to reduce center to center.

You could build cardioid low-mid arrays with 8" drivers up to 800Hz if you had a room placement problem.
 
Line arrays with even 2” drivers, combing has them rolling past 1khz.

I can link to the kuze array On partsexpress.

The beauty of the 8” is the lack of dispersion that would allow more drivers to share the bass without combing away the highs.

Single 8” off the floor didn’t have much bass further than 7’ away.
 
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Paul hynes used 8x8" b200.

"Nominally 8" drive units and so this would be a theoretical no-no regarding comb effects. However, in practice they sound great and i am not finding any audible problems with combing effects at a listening distance of around twelve feet."

Lowther Array Open Baffle?

Fullrangeman in a post below him did not have a problem with 4 x 10" fullranges.
 
A few comments on a line array with 8" diameter drivers: You may be able to get away with it if your application is for voice reproduction in a PA system, but for music and such you really need smaller diameter drivers to have quality high frequencies.

My most recent line array design was my Modified CBT24 discussed in:

My New Line Array--It's a Modified CBT24

The small diameter drivers (as previously mentioned by bradleypnw) do a great job in their ability to reproduce full frequency with help of subwoofers in the CBT design. The CBT design does not exhibit comb lines as you can listen to them 2 inches away, 2 feet away, and 10 feet away and not hear combing. Don Keele mentioned this characteristic in several of his CBT papers and I can attest that my CBTs have similar performance.

In message #5 of my Modified CBT24 thread above I mention my changing view on listening to comb lines from a straight array.
 
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I’d like to see a step response or an impulse response from the CBt array.

Not that a full range driver does a great job, but I’d like to see something similar to a square wave (like a 6db time/phase aligned thiel or vandersteen)........
 
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