Cloning IDS-25s

[koldby]

Originally Posted by haraldo

Pardon me if this is a stupid question, but..... well, actually my father told me there are no stupid questions, only stupid answers

Could it be that the ribbon tweeter in the middle of the line source, as is on the Adyton's... are there to fill in some of the high frequency loss you otherwise would have and as such meaning, less eq need in the high frequency band?

That is excatly the reason for putting it there and Adyton dosent even roll of the Vifas, they only have a highpass for the tweeter.
The problem with such an arrangement is that there are only , in theory, one correct listening distance because the tweeter is a point source and the rest is line source. That meens the line source will only loose 3dB for every doubling of the distance and the pointsource looses 6 dB,

Koldby

[koldby]

A lot more information here:
Stupid Cheap Line Array
And here:
Stupid Cheap Line Array
Stupid Cheap Line Array

[ArtsyAllen]

The battle between my Cheap and Cheerful Full-range array with the Poineer 4" drivers and my Avebury system with the Mark Audio Alpair 12 goes on...

One thing is clear, I want to pursue this array idea more seriously.

The Avebury has the intricate, full bandwidth sound, with lots of details.
The Cheap and Cheerful puts you in the music. I really like that, and it would be a clear winner if it had the Downward Dynamic range of the Avebury. Yet we are comparing a 50 cent driver to an Enabled Mark Audio flag ship driver. So I am thinking a full-range line array with a better driver would be the best of both worlds! So my fear has been, that if I go the Vifa route, would I be always wondering if I should be more patient and save up for a higher performing driver...

Originally Posted by koldby

The Vifa source is my main reference speaker. Eventually I will mate it with a IB subwoofer as it cannot play loud enough in the bottom octave to my taste.

These are amazing speakers!!!
The best I have had. A little trick:
Put a little Isopunkt made thinner with turpentine on the paper cones and let oit harden in UV light. Takes them a step up in clarity and definition.
It is closed boxes both of them.
The alu boxes are actually a little too small, but when the subs are ready, makes no problems.
They play insanely loud when crossed over about 80-100 Hz.

Koldby

Thanks Koldby, you answered many of my questions, as I enjoyed following your project on the "Stupid cheap line array" thread.

Naturally I was curious if you had moved on to wanting to try a different driver or not, but apparently you are so content with the Vifas, that you have not built your line source tweeter yet. It seems a sub-woofer is a must, especailly for movies, which I am willing to accept, becuase after all, my Avebury needs a good sub-woofer for movies!

What is Isopunkt? I would like to consider driver treatment for my current Cheap and Cheerful array, but want to stick with proven methods as I do not have extra drivers to fail forward on!


You also mention that your aluminum enclosures are too small. I am planning on building a cabinet for 25 drivers (in the shape of a tube) using birch plywood for the internals and solid wood laminated on the outside with each driver in its own enclosure. If you where to optimize your cabinet size, how big would you make the internal volume for each driver?

I have been looking at various drivers for a full-range array, mainly the Vifa, the Fountek 85 or 88, or the Mark Audio CHR-70.3.

I am surprised Scott Moose promotes the Fountek 85 over the 88. It certainly is more appealing to the pocket book.

Also, I have noticed that Mark Audio has created a modular line array cabinet with even a passive EQ circuit if one does not have an active EQ to use:

http://www.madisound.com/pdf/TheCHRA...lan-250811.pdf

The modular concept allows one to build their array a piece at a time. Quite costly if you want the full 18 driver array, could buy a pair of B&G Rd-75's for that, although would have to build a sub-woofer system that can play up to 300 Hz, perhaps a line of 12 - 8" drivers. Agian getting up in $$$$!

Also, the fountek and MA's do have them big bessels! I know it does not make that much diference, I just like the idea of activating as much of the vertical surface as possible. The good old Vifa just seems to fit this application so well and it is affordable!

I just know you do not need to spend heaps of money to have fun, the Cheap and Cheerful project proves that!

God Bless,

Allen

[haraldo]

This is very interesting info here

If you look to the experience from Roger Russel, who spent a lifetime building line sources, he made all sorts of the type, 2 way, 3 way, all kinds....
tweeter in the middle, no tweeter in the middle....

Ending up with the IDS-25 in the end as the best he ever did, probably simplicity is the thing here.

Probably the way to go is a simple FR line source with or without a tweeter in the middle, utilizing some sort of 3.5" - 4" driver that will mostly cover the range from approx 100Hz and up....
Still I wonder how this can work well with a tweeter in the middle, changing from line source to point source in the treble, and also how this affects phase/time, the phase of the treble must be very weird with these two topologies working within the same passband.....

In addition I would like to employ a line source subwoofer system that uses a range of 6.5" - 8" drivers in a transmission line, probably to be crossed around 125 - 150 Hz, using two these subs of course

Probably much easier to get this to integrate properly than dealing with crossovers higher up in frequency where it will be much more critical, audible and difficult to deal with, I think there are some few drivers out there that will fit to a system like this. Scan speak and Seas make some woofers that probably will work quite well like this, and if you employ 8 woofers in each sub the linear excursion limits will never even be close to exceeded

[Scottmoose]

Originally Posted by ArtsyAllen

I am surprised Scott promotes the Fountek 85 over the 88.

Not so, I only said that's what Adyton Audio appear to be using in their boxes.

[planet10]

Originally Posted by ArtsyAllen

Also, the fountek and MA's do have them big bessels! I know it does not make that much diference, I just like the idea of activating a

The Fountek have a very tight bezel.

Put FF85wk on your (cost no object) short list.

dave

[Pnotus]

Originally Posted by koldby

The problem with such an arrangement is that there are only , in theory, one correct listening distance because the tweeter is a point source and the rest is line source. That meens the line source will only loose 3dB for every doubling of the distance and the pointsource looses 6 dB,

Koldby

This seems right. Isn´t this also true for the upper frequency range in a fullrange line array?

I really don´t know, I´m just curious about the cornestones of line array design. So I mean no disrespect towards your stunning array build.

/Pontus

[ArtsyAllen]

Originally Posted by Scottmoose

Not so, I only said that's what Adyton Audio appear to be using in their boxes.

I stand corrected, Thanks

Originally Posted by planet10

Put FF85wk on your (cost no object) short list.

dave

I'll do that. FF85wk is doable, sure it is a little more then the Vifa, but the cost is still with-in the reasonable range. The FF88ex is a whole nother story! I certainly like the look of the metal cone over the paper.

Allen

[planet10]

Originally Posted by ArtsyAllen

FF85wk is doable, sure it is a little more then the Vifa, but the cost is still with-in the reasonable range. The FF88ex is a whole nother story! I certainly like the look of the metal cone over the paper.

Our experience has the Fountek a notch down in performance than the FF85.

dave

[ArtsyAllen]

Okay: Fountek has a FE85 and a FR88ex
Fostex has a FF85wk

Originally Posted by planet10

Our experience has the Fountek a notch down in performance than the FF85.

dave

So in other words, the Fostex FF85wk is a notch up in performance compared to the Fountek FR88ex, and costs less also. Price is comparible to the Mark Audio CHR-70.3. I like the bessel on the Fostex FF85 for this application.

It looks that the Fountek FE85 is comparible to the Vifa...

Oday that is enough mistakes for me for one day!

Time for some sleep

Allen