Single Driver in an Array????

[broncosaurs]

I have a question about line arrays with a single tweeter or any single driver with an array. Would not the single tweeter drop off at the 6db/double distance and the array is dropping off at a 3db/double distance? So if sitting a little to close the tweeter would be overbearing and at the farther distances it would just drop off to almost nothing compared to the array? I have seen this “single speaker in an array” used in many different designs. It just does not seem this would work well. The reason I started to think of this I was thinking of doing an in-wall array for HT but could not come up with a center channel array that I think would work. Thinking the array needs to be longer then the max and min height of the listening ears. So I thought of some other center channel, not array, and then thought this speaker would drop of at the 6db/double distance compared to the 3db of the array. This is what led me to thinking of the single driver on an array might not make much sense. Any thoughts?

Brad

[thylantyr]

To me a line array is an array of both mids
and tweeters, etc. not an array of mids and
one tweeter, that's like a hybrid design with
compromises. If you are clever, you can make
any design work.

Whatever you choose to do, always make a
cheap prototpye cabinet to test the sound.

[Paul O]

Hmmm.. I can see this being something of an issue if people are listening from various distances at the same time. Depends how big your listening room is. Balanced levels between the mid-array and single tweeter at one position, could give bright sound closer, or dull sound further away. I don't think you will ever get extremes like all tweeter up front and none at back, the average listening room just isn't big enough. Another compromise in a long list that will have an effect, but are probably not deal breakers.

[Andy_G]

Unless you have a VERY long lounge room and run bakwards and forwards while listening you are not going to notice it.
So long as they are balanced for your normal listening distance, a couple of feet backward or forward is not going to to make any audible difference

As for the centre channel to match line array fronts, have a look at DK's "Cynasure" on the Project Showcase.

[broncosaurs]

The room is 25’ wide by 36’ long. Projector on one end with the in wall line arrays and theater type seating. The other end has a pool table. People will be as close as say 12’ too as far away as 33’. I wanted to use line arrays to keep the sound level in the room as balanced from front to back as possible. As I understand this type of system, if the speaker was balanced for the front position at 12’, at the 24’ mark the array would be 3db down and the non-array speaker would be 6db down, which, I think, is ˝ as loud. This would seem to hold true with both the problems I mentioned on the first post; if an array used a single tweeter or if in an HT setup the sides were arrays and the center channel was not, I don’t think they could ever be balanced correctly for the room, just one distance.

I hope I made some sense of this whole thing. Maybe I should have broke it into two posts but I see it as the same problem of arrays mixed with point source.

Brad

[Andy_G]

> The room is 25’ wide by 36’ long.

Ahhh..more info ! In this situation it probably is advisable to use an array of tweets. Does become more costly though.

You do have to weigh that up against if the guys playing pool at the back of the room will actually notice the drop in top end...
In fact it may actually be a good thing to let the top end die a bit from the front, where you might be sitting listening intently, to the back, where it will be more of a background music effect.

[christianb]

I have a hybrid array with 10 mids and a single Fountek JP-2.0 tweeter. I listen only at my listening spot so I created the crossover to work at that one spot. Granted, my crossover is an active DCX2496, which makes changing crossover settings a breeze. I also EQed my room with the DEQ2496. Together, they're a winning combination.

[cptomes]

> ...if the speaker was balanced for the
> front position at 12’, at the 24’ mark the
> array would be 3db down and the non-array
> speaker would be 6db down, which, I think,
> is ˝ as loud.

Yes, but human ears are nonlinear. 1db difference is that standard for what most people can tell is a difference in sound. iirc, 10dB is perceived as twice as loud.

Here's just one hit I got when googling the topic.

<A HREF="http://www.lenardaudio.com/education/03_db.html">http://www.lenardaudio.com/education/03_db.html</A>

In short, set it for "perfect or close at your favorite distance and let the rest of the room hear different performance. Human hearing compensates for different sounding speakers all the time, just like your eyesight compensates for light/dark and fluorescent/tungsten/sun light.

I just built a set of (8) NSB and (1) Dayton neo tweeter. I was running it full active with a DCX2496 and a pile of Carver amps, now using the BIC plates Aaron (sp?) was selling reconditioned a month or two back. I built a passive for the line/tweeter and we're using the natural rolloff of the NSB for the highpass there. The plates have an adjustable filter on them and can be bypassed. Jury's still out on higher frequency performance with them.

[unknownuser]

> I have a question about line arrays with a
> single tweeter or any single driver with an
> array. Would not the single tweeter drop off
> at the 6db/double distance and the array is
> dropping off at a 3db/double distance? So if
> sitting a little to close the tweeter would
> be overbearing and at the farther distances
> it would just drop off to almost nothing
> compared to the array? I have seen this
> “single speaker in an array” used in many
> different designs. It just does not seem
> this would work well. The reason I started
> to think of this I was thinking of doing an
> in-wall array for HT but could not come up
> with a center channel array that I think
> would work. Thinking the array needs to be
> longer then the max and min height of the
> listening ears. So I thought of some other
> center channel, not array, and then thought
> this speaker would drop of at the 6db/double
> distance compared to the 3db of the array.
> This is what led me to thinking of the
> single driver on an array might not make
> much sense. Any thoughts?

> Brad

Yes what you are really doing is combining a point source with a line source and the drop off is like you stated. I have seen line arrays with a single tweeter and they can work but they have to be optimized for the listen distance. As you move further out from that distance the tweeter is going to drop off. One other problem is finding a tweeter with a high enough sensitivity to keep up with the increased sensitivity that results from an array of woofers. It can work if you keep those things in mind and remember to measure the system and design the crossover at the actual listening distance.



(Originally posted by: Dick M.)

[Andy_G]

try these: Vifa DX25, AC25SG or H26, Peerless horn loaded.

The Fountek ribbon is around 96dB, but be careful because they don't like being over-driven

there may be some with high sensitivity made by others, but I can't list them.

[unknownuser]

A focused array, I've even seen a focused array with 1 tweeter in the center.
Here is one
<A HREF="http://www.gryphon-audio.dk/images/p...poseidon/1.jpg">http://www.gryphon-audio.dk/images/p...poseidon/1.jpg</A>

Below are some links to curved (focused) full range driver arrays.

<A HREF="http://db.audioasylum.com/cgi/m.mpl?for">http://db.audioasylum.com/cgi/m.mpl?for</A> … p;session=

or here (good picture near bottom)
<A HREF="http://yu-ra.tripod.com/array.htm">http://yu-ra.tripod.com/array.htm</A>

or even this one (a 15 unit curved array)
<A HREF="http://www.geocities.com/dmitrynizh/labaffles.htm">http://www.geocities.com/dmitrynizh/labaffles.htm</A>




(Originally posted by: norman bates)