AudioFred Messages: 377 Registered: May 2009 Location: Houston
Illuminati (1st Degree)
Here's one that uses the new Dayton ND90 3" full range drivers. I know there's a comb effect issue with this kind of array, and that the array needs equalization, but I heard Roger Russel's IDS25's at the 2007 RMAF, and they sounded very good. Not $18K good, but this version will cost more like $1K or less.
There is a huge comb effect with those 3.5 inch drivers, and no transition to at least a single high SPL tweeter(thought preferably a line).
When I first hooked up my Three way Tri-amp system, with the 3 inch 3mm xmax Sammi's, it was using only them and not the two 12 inch 15 xmax DVC woofers, or the 60 ND20A tweeters.
I thought the sound was great. I used a 1/3 octace equalizer, and i was impressed. But when I hooked up the tweeters, and the woofers, I discovered the missing sound. I disconnected the equalizer, and haven't used it since.
My recommendation is that at least one very high efficiency tweeter should be used. You will notice the difference immediately.
AudioFred Messages: 377 Registered: May 2009 Location: Houston
Illuminati (1st Degree)
Eric J wrote on Tue, 11 August 2009 06:18
I thought the sound was great. I used a 1/3 octace equalizer, and i was impressed. But when I hooked up the tweeters, and the woofers, I discovered the missing sound. I disconnected the equalizer, and haven't used it since.
That's the most frequent reaction I've heard about full range driver line arrays. The shortcomings are subtractive, so you don't notice them until you compare to an array with a single line of full range drivers to one with separate lines of woofers and tweeters, and only then do the advantages of having a separate tweeter array become obvious.
The examples I've heard at the RMAF, incuding Roger Russell's array and the Audience arrays, sounded very good to me, but they did lack that last bit of "sparkle" you hear with a high quality tweeter.
And here is Russell's explanation of comb filtering in his line arrays, which concludes that it is clearly measurable but it isn't an objectionable quality. His conclusions are consistent with my brief listening experience, but I would need a more extended listening opportunity to be convinced.
I think that comb filter distortion pretty much depends on who is listening.
Since Jim Griffen has clearly indicated that human perception drops of dramatically and increasingly from 10-20 khz, and increasingly with age. Depending on how much each individual can actually hear of those high frequencies is dependent on what they mean to each person.
This is what Jim actually said about it:
"Comb lining will dull the highs and will be most noticeable in the lack of air (dull highs) especially as you move off axis. Essentially, the high frequencies are rolled off as the ensemble of the tweeter outputs don't add up but start to cancel. Now the ear is less sensitive in the upper octave (10-20 kHz) you may not observe the full impact of this effect. But if you compare to an array that is properly designed, then there is no comparison as the proper array will yield a more airy (and accurate) sound."
Jim Griffin on PE technical discussion board : 11-21-06
I've read Russell's response, and in fact have a pdf saved copy in my files. All I can say is that if you take a system adjusted for reduced CFD and one without that scriptor and listen to them side by side you will hear a difference. Unfortunately Russel probably can't hear it. He's way older than me and I'm 60.
AudioFred Messages: 377 Registered: May 2009 Location: Houston
Illuminati (1st Degree)
The design work continues. This line array now has the power of not just 24 three inch radiators but a total of N = 5 x ( 24 x 4) = 480 radiators. That's for just one line.
darkmoebius2 Messages: 37 Registered: August 2009 Location: Los Angeles, CA
Baron
That Dayton ND90-8 is one interesting driver!
Looking at his driver tests, it fills a lot of requirements for those looking for a 3" widerange driver. I just wonder how it sounds? Does it get tonality right?
FR test to 3kHz (limit of test methodology)
Groundplane test - 1W (2.83 Vrms), 1 meter outdoors (includes some local reflections)
selahaudio Messages: 56 Registered: September 2009
Baron
darkmoebius2 wrote on Mon, 28 September 2009 23:14
That Dayton ND90-8 is one interesting driver!
Looking at his driver tests, it fills a lot of requirements for those looking for a 3" widerange driver. I just wonder how it sounds? Does it get tonality right?
selahaudio Messages: 56 Registered: September 2009
Baron
AudioFred wrote on Mon, 28 September 2009 15:28
The design work continues. This line array now has the power of not just 24 three inch radiators but a total of N = 5 x ( 24 x 4) = 480 radiators. That's for just one line.
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