Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

[rmeinke]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Congrats Javi!! And we were nervous about the bass performance... so happy to hear you like them!!

I haven't started mine yet. Instead I've been playing with DML panel's and have really enjoyed the results... er... the promise of an amazing result... lots of promise.

After you take a nice long rest (fingers must be raw) and just sit back and enjoy the new kick a$$ line arrays and want an EASY PEAZY build (you can get a panel speaker together in less than 2 hours!!!) you might want to consider a DML panel for ***** and giggles. Certainly won't be as awesome as the FE-83 line but just plain old DIY fun and another different presentation to enjoy!

Looking forward to pics!!

[natehansen66]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

As it is, the only thing that worries me is - whether the drivers can do real bass. I don't want to use a subwoofer - I want a full-range line array. If I use a sub I'll have tons of integration problems, since the subs will be point sources and the speakers are line-arrays. Everything will sound OK only in one point in my living room.

I'm sure you're array will suffer the same modal issues that a sub would.........I don't think adding subs would bring any more integration issues than they do with a "traditional" speaker. You'll likely do away with the floor bounce and the vertical directivity of the line ought to mitigate the ceiling bounce as well, but below 80hz I don't think it would be much different than a regular speaker.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Sorry for not answering earlier... I've been sort of busy at home - yes, part of it had to do with finishing the speaker.

I'll do a separate post about the building of the speakers. It was easy, but very, very time consuming. I'd think it took close to 30 hours - not counting cabinet work. And EQ'ing the array took close to 6 hours.

In a way, it's strange... since they use a MiniDSP, tuning them was so easy. But it's so much work...

Anyway, here are my listening impressions after all this time with them.

How do they sound?

After living with them and listening to them for hours, alone, with my wife, with mom and dad, and as a background speaker, this is simply the best speaker I've ever listened to. Everything Roger Russell said about the design is true, in a way I never expected. Period, end of story, nothing else to be said.

Still reading this? Good... because there are some things I need to clarify about that statement.

Driver choice

I will not say driver choice was a mistake, because the only reason I bought 51 Fountek FE-83's (one extra, in case anything happened - nothing did) was because of the price. I actually dared to build the line array because of the price of the Founteks. So it had to happen this way.

But, in hindsight... aw, I don't know. I saved about $180 by not buying the Vifas the original design used, and tons more by not using the, say, Dayton ND-91 of J.L. Murphy's project (http://www.trueaudio.com/array/downl...%20Project.pdf). Almost the same SD, than the Vifa and the same as the Dayton, a bit more XMax than the Vifa, a bit less than the Dayton, it should work, right? Right?

It should have, but I believe the XMax is wildly overrated on the Founteks. This is in no way close to the Dayton's XMax. I know - I have a mini speaker based on it, and the Daytons go crazy loud when pushed hard without too much drama. The Founteks? My SWAG is they are closer to 1.5mm Xmax. No joke. Which leads to...

Measured performance

I'll be posting actual, measured FR. later Suffice to say, I got it completely flat within a short time frame. Then I used Dr. Sean Olive's preferred room correction curve (http://seanolive.blogspot.mx/2009/11...uation-of.html) which is basically a -10dB slope from 20 Hz to 20 KHz in a straight line. I EQ'd each array separately, so they both hit the sweet spot with mostly the same FR.

I then measured distortion in a very, very informal way - by using an RTA and a tone generator. The array, above 100Hz, had 2nd and 3rd distortion levels 50 dB and lower the fundamental everywhere at about 105dB. Impressive. I hit 110 dB with an 80W amp at 100 Hz.

And then I tried to go lower...

The truth is - the array can probably hit 30 Hz at 95 dB, tops, without major distortion levels - the 2nd order being 10 dB down the fundamental. Yes. It's bad. The drivers can't take anymore.

So, how come I'm listening to such good bass?

It's sort of simple. Rock music at concert levels is out of the question. I have no doubts an array based on the ND-91 would work, and that the Vifa based array does work indeed. But with Founteks? These drivers are XMax limited. They aren't close to 3 mm. And without much copper in the motor things don't look good - on paper.

But...

Real life performance

The speakers are in a room, which somewhat boosts bass. And I honestly don't listen to music at ear splitting levels that much. 95 dB is not that bad for my listening habits. And that's peak. With a constant sine wave.

I dialed in a 24 dB/oct L-R crossover on the MiniDSP at 30 Hz and eased up on the EQ. I'd say the array is flat down to 45 Hz and then drops gradually up to 34 Hz. It sounds like a nice sealed speaker. No, I didn't get sub bass levels.

But what I get is AMAZING. No room nodes whatsoever, and while listening at sane levels distortion is kept under control by a milder EQ curve and the crossover.

In retrospect, I should have bought the Vifas. But then again, I wouldn't have tried the array if not for the Founteks. And...

The real proof - music listening

...we are back on square one. How can I think these are the best speakers I've ever listened to, considering the Founteks couldn't go as low and loud as I wanted them to?

Because... these are the only speakers I've ever built that have made my jaw drop every single time I play them - and actually have made other people go... "what on EARTH are these things?"

To say they are jaw-droppingly good is an understatement. These are in a completely different league than anything else I've built - if you can live with the bass limitations. Sure, my twin 10" woofer design is far, far, far more visceral and loud. But that's pretty much the only speaker I've built that beats it in a specific area. The rest are inferior in every sense.

Classical music is out of this world magical. That's the only word I can think of. And if it' a live performance it's even more so. Listening to these you realize traditional speakers will never, ever be this good. Nothing I've heard on a store can even come close. No flat panels, no dynamic drivers, no mega-buck brands, no tall speakers, no mini-monitors, nothing. You think you've heard imaging? Ambiance? You've never, ever listened to anything even remotely similar. The cliche "like being right there" takes on a whole new meaning. You are inside the performance like never before. It's a feeling of being absolutely surrounded, enveloped, inmersed in music I've never felt. Like having the world's biggest headphones - but with a tremendous sense of space.

Stand up? Sound won't change. Sit down? it's just the same. Walk around the room? WHAT'S GOING ON? Sound doesn't change - at all! Walk away? Still the same. Get close? OK, if you are 1 m away you start listening to each driver. But who listens that close? Not me.

There's no comb filtering at work while at 2m, or more. I know what theory says - that comb filtering should destroy highs. Ha. I can't think of clearer, purer, non-distorted treble in any driver I've heard. This is real treble. This is midrange magic.

Jazz? Breathtaking. Small ensembles? Bigger than life. Acoustic music? Out of this world. Background listening? Done. Even rock, at sane listening levels, sounds great. Overprocessed studio recordings can sound weird at times, though - not at all like traditional speakers. It takes a bit of time to get used to them. Things sound bigger than they should. But live recordings? Oh boy. It's the world's best surround sound system - from two tall columns. You have to listen to them to understand it.

Yesterday, mom and dad came by and listened to them. They are no audio strangers, having a museum-like MC-240 and MX-110 at home. I played Vivaldi's Four Seasons, a live recorded concert. Both were astounded - my dad said he never thought anything could sound remotely like the concert hall they go to each week - but this was just a perfect recreation. They stood up, walked around, played piano concerts, full orchestras, violin quartets - they just couldn't stop.

As do I.

What now?

The subwoofer issue. I know many of you think I can integrate a sub with these things. I'm not so sure due to two things.

1) The sub is a point source, after all, and it decays faster than a line array. I know it's omnidirectional, but I fear it'll only sound properly at a single point in my room.

2) Although I do have some nodes due to bass at my room, honestly, the bass of the speakers is so clean and well integrated I'm not sure I'd trade higher listening levels for the level of coherence I have with my system now.

I'll probably get a nanoDIGI and do EQ completely in the digital domain, and add a DAC. Right now, I'm doing an unnecessary extra A/D - D/A conversion at the MiniDSP.

I'm strongly considering eventually buying 50 ND-91s or Vifas and building a true line array with no limitations. The only problem is - and it's a big one - I have nowhere to put the original array. And I'll need to save for a future one. So these plans will be if I ever decide to build something else - maybe in 2 years. Who knows, I could try ordering 5 or 10 drivers from PE every now and then. I could see myself living with an upgraded version of the array for the rest of my life (no joke - they are that good).

If you haven't listened to a full range line array, try it. This is exactly the kind of magic I hoped I could attain with DIY. You won't be disappointed. I wasn't!

[christianb]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Welcome to the party!

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

First -the crossover curve.

Something to notice. I started building the EQ using the MiniDSP 2 Way Advanced crossover plug-in. But the 12 parametric EQ bands, although useful, didn't get me as close as I wanted to the desired curve. So I bought the basic 2 Way plug-in, which has a 31 band EQ. I got the curves pretty fast after that.



Channel 1 of EQ.


Channel 2 of EQ.


I then measured FR at the listening position on SynRTA and exported data to LSPCad. FORGET about doing an MLS on a line array. It's like measuring a pound of sand with a ruler. It just doesn't work. This is an unsmoothed (1/48) SynRTA measurement vs. the 1/12th smoothed measurement.


Finally, the slope. Optimized at -1dB / Oct, 10 dB's across 20 Hz - 20 KHz.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Welcome to the party!

Are those Dayton ND-91s? That looks amazing! Am I right in thinking the Daytons can do lower bass?

[thekorvers]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Nice writeup and interesting observations.

I think using a subwoofer will be less of an issue than you anticipate if properly integrated. As you are aware, sub frequencies below 100 Hz are non-directional and at the point where you should be crossing these, even less so. Yes your sub is a point source, but the point becomes rather blunt at lower frequencies and becomes a rather wide pressure wave rather than a pointed directional higher frequency wave. IMO two or more subs strategically placed will totally remove your concerns once you listen.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

You know, I just remembered I have an under-used 15" Adire Audio Tempest (remember those?!?!) in a sealed enclosure with a 500W amp....

Hmm, crossed over at 100 Hz I could put it between the two towers, back in the corner of my house. Dial a little delay on the arrays, cross over sharp and fast with 48 dB/Oct L-R filters... I could try that...

[Tin_Ears]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

You know, I just remembered I have an under-used 15" Adire Audio Tempest (remember those?!?!) in a sealed enclosure with a 500W amp....

Hmm, crossed over at 100 Hz I could put it between the two towers, back in the corner of my house. Dial a little delay on the arrays, cross over sharp and fast with 48 dB/Oct L-R filters... I could try that...

Sounds like a plan. I suggest you also experiment with 80Hz and 60Hz but the latter "might" be pushing the limits of the arrays.

[thekorvers]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Sounds like a plan. I suggest you also experiment with 80Hz and 60Hz but the latter "might" be pushing the limits of the arrays.

I agree. 100 Hz seems a little high. 70-75 Hz is a good number.

[careyink]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Very ambitious! Love those cabs, hope it all works out for you! I think the efficiency gains and floor-to-ceiling array effects may give you a healthy boost in the bass department, I don't think 20hz is a sure thing, but you should be able to get to 40hz quite comfortably.
I'm enjoying my mini - arrays with 8 of these per side.

AdamG did you post pics of that build anywhere and over all impressions?

Fjhuerta this is AWESOME!!!! I used two of these little full ranges in boom box's for the kids and they are okay but with your description of the sound of the array I really want build a pair!!! Nice job

[Jay1]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Why not build a woofer tower to match the height of the array? Isnt an 80hz wavelength like 14 feet? You could put a single woofer at the top and a single woofer at the bottom without issue.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Thank you all for your suggestions and congratulations! A two woofer line array sounds like something I could try later this year, when funds allow (although this was a "cheap" speaker, once I added every single part I used I spent close to $1K - not cheap at all).

The next thing I'll do is add the 15" sub. I want to see how rock played at concert-like levels sound. I can imagine live albums will sound just as good as classical music (I'm specifically thinking the latest David Gilmour concerts, for example).

Is this the proper way to figure out the best crossover frequency for the sub?

* Run a 2nd, 3rd, 4th and 5th order distortion test with ARTA at about 110dB and find out where my issue starts.
* Integrate the sub with the MiniDSP (level / EQ / delay) with the main array.
* Try different order filters, find out which ones have the lowest distortion products at the listening levels.
* Listen to the best filters, pick out the best by ear.

Is this a good plan?

[nottaway]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Excellent work!

Do you have a native FR for a single driver you could post by chance?

[saabracer23]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

This looks like a really cool project. I've noticed that you have mentioned the ND-91 a few times, would it be worth the savings to use an ND-90? One fear I have is that the ND-90 wouldn't have the treble of the founteks.

Dan