IDS-25 Line Array with Super-Tweeter

[slhijb]

Considering building an IDS-25 clone line array and adding a super-tweeter similar to the Adyton Imagic 2.0. I have a pair of NIB Fountek NeoCD 2.0s ribbon tweeters left over from an unfinished project that I’m itching to use. Each speaker will have 24 Vifa TC9FD18-08 FR drivers with the super tweeter placed at the center of the column (12 drivers above & 12 below). Drivers will be placed in 6 separate compartments of 4 drivers each.

Seems best to let the TC9FD18-08s operate undisturbed full-range and roll-off naturally. Then phase in the super-tweeter somewhere between 10kHz - 15+kHz with a small single series capacitor (1.0uF or less). Not sure if it will need a series resistor or variable “L” pad. Wondering if one of the dials on the back of the Adyton Imagic 2.0s is a variable “L” pad they call “Presence”.

No Xover on the TC9FD18-08s. Will use an equalizer - Behringer DEQ2496. Hope this will help blend in the super-tweeter.

Several that have built IDS-25 clones stated they would like to add a tweeter for a little more top end. Wondering if anyone has done this; if so, how did it workout, any advice, modifications? Comments are greatly appreciated.

Listed Efficencies
Vifa TC9FD18-08 - 83.5dB (I believe Zaph measured it at 82.19dB) 1W/1m
Fountek NeoCD 2.0 Tweeter - 97dB 1m/2.83v
IDS-25 - 92.5dB (Roger Russell listed + 10dB for line array using similar Vifa TG9FD10)

Vifa TC9FD18-08
https://www.madisoundspeakerstore.com/approx-3-fullrange/vifa-tc9fd18-08-3.5-full-range/

Fountek NeoCD 2.0
https://www.madisoundspeakerstore.com/ribbon-tweeters/fountek-neocd2.0m-blk-5-ribbon-tweeter-rectangular-flange-black/

IDS-25

Adyton Imagic 2.0

An externally hosted image should be here but it was not working when we last tested it.

 

[wesayso]

I'll be looking at the thread for your results .
It was on my agenda of things to try but haven't felt the need yet. Though I'll have to admit to be curious to see/hear the results... (or at least to read about it )

 

[Jim Griffin]

Needles Line Array

Once upon a time, long, long ago I designed and built a line array with 16 Tangband w3-871S woofers and an Aurum Cantus G3 ribbon tweeter in the center.

http://www.diyaudio.com/forums/multi-way/43430-jim-griffins-needles.html

See also:

http://www.audioroundtable.com/misc/nflawp.pdf


I still use these arrays in my downstairs living room.





Jim

 

[slhijb]

Can't tell you how closely I've followed your threads on this. You designed and built a beautiful pair of arrays.

 

[slhijb]

Jim, thanks so much for the response. Not often I hear from someone with you extensive background. The "Needle" looks fantastic and if you decided to keep it as you living room speakers all these years, sure they sound great as well.

 

[rockk19]

I believe you'd need much more steeper filter than just a capacitor. The tweeter will be at higher levels than any of the TC9 drivers. This will cause serious dips along the vertical line of the speaker's response. If you cross your 97dB supertweeter at 10KHz with a first order high pass filter, 7.5KHz response will be only 3dB down, i.e. 94dB. 5KHz will be 91dB. This will burn some serious holes in vertical line response of your arrays. You may use an L pad attenuator, but you'd still need a steep filter.

You may think about a rear firing, up firing or a normal front firing super tweeter with delay. At least thats what I am thinking about these days

 

[wesayso]

Can't tell you how closely I've followed your threads on this. You designed and built a beautiful pair of arrays.

I think this was aimed at me? Thanks for the compliment.
My reasoning for building arrays without a tweeter came to me by reading up a lot on them (everywhere). I'd only choose it on a tall enough array. Floor to Ceiling tall (at least more than 70% of the real floor to ceiling height)

I found some papers from David Smith (speaker dave on here) from the time he worked at McIntosh regarding tweeter array measurements. He was Mr. Russell's successor there and basically had the same conclusions at that time. If the array is long enough, no shading is needed. The distance between the tweeters in that test array was no less than I could manage with my full range speakers. So I figured it should work and went on to build them, without any shading planned.

I know and have read the paper from Mr. Griffin. But decided to go ahead with a full range array anyway. The main reason for me was to have no need for a crossover. I wanted to build time coherent speakers. Very hard to do with crossovers involved. I don't regret my choice. With FIR processing I'm able to make it into a phase linear system.

Different choice from what you're aiming for. But I figured it might help to explain my particular choices.

I'm very interested though in every variation on the array theme. Especially interested in the ideas on how and where to crossover from the single tweeter to the line.

I might experiment with the idea rockk19 proposed for you. Ever since I saw that being mentioned in the big "Beyond the Ariel" thread I've been curious about that. I mentioned it in one of the Array bundle treads on here somewhere. Basically a delayed helper tweeter for ambience.