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

[fjhuerta]

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

I have never used the ND-90. The ND-91 is a cool little driver, but without EQ I never liked it as a full range. Nevertheless, with EQ I see no reason why it shouldn't sound better than the Founteks.

For use with a tweeter I prefer the ND-105, it has far more bass and output.

[fjhuerta]

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

I started doing tests in order to integrate my sub and I ran into a strange problem I don’t think I’ve ever had before… any help will be greatly appreciated.

I tried running ARTA’s distortion sweeps, but my card started acting up, so I had to use iOS AudioTools, in order to get a quick idea of where my issues were. I didn’t do screen captures, but the frequencies with the most distortion are:

100 Hz
50 Hz

Distortion at 90, 60, and 40 Hz is LOWER than distortion at 100 Hz. At 80 dB's fundamental, there’s 70 dB of 2nd order distortion and 79 dB’s of 3rd order! It’s crazy.

I can’t imagine why a driver would have MORE distortion closer to its Fs than below it.

A sub won't help since it'll play below 100 Hz. No crossover filter will help. I need to fix this problem first.

I'm guessing the issue is the mounting technique.

In order for the drivers to “breathe” I chamfered the rear of the baffle, so there’s not much wood where screws can “bite” into. I assume that at 100 Hz the system enters a resonance of its own, and the drivers are vibrating hard against the baffle and creating distortion.

The drivers’ mounting flange isn’t flat. They have a “lip” that seems to cut into the wood. I added gasket tape to the recess created by he mounting lip, but I assume that it isn’t compressing at all, or even touching the baffle.

My question is, do you think that adding extra tape, so that it can compress against the wood and keep the lip away from the wood, would help?

[saabracer23]

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

I have never used the ND-90. The ND-91 is a cool little driver, but without EQ I never liked it as a full range. Nevertheless, with EQ I see no reason why it shouldn't sound better than the Founteks.

For use with a tweeter I prefer the ND-105, it has far more bass and output.

So I take it that means you'd rather use the vifa then? I ask because earlier you were mentioning the Dayton and the vifa for possible better results. I'm basically curious which I should purchase if I pursue this design, Dayton or vifa. The vifa is cheaper...

Dan

[fjhuerta]

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

I'd get the Vifa, since it's the driver Roger Russell used. It's a sure thing.

[rmeinke]

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

Hello Javi, if it is the frame chattering against the baffle it seems that more foam tape should certainly help. You might need a "tough" material like felt to prevent the frame lip from eventually cutting through the gasket.

Maybe test with one driver to get it the best you can, then rise and repeat for the remaining drivers!?!?

[rmeinke]

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

I'd get the Vifa, since it's the driver Roger Russell used. It's a sure thing.

This is the Vifa that Roger likely uses in this array - http://www.parts-express.com/vifa-tg...ange--264-1064

The paper cone Vifa is cheaper and a good performer... almost half the price of the one Roger uses. That's solid.

I'm still going with the Fountec. For the money it still seems like the value leader. I plan on mounting the drivers from behind... there just isn't enough room for them to breath and get solid hold from the screws with a front mount... just to small unfortunately. A little horn loading can't to much in this situation. Mine will be in an open baffle so I really hope to avoid the frame/seal issue altogether.

Thanks Javi for taking the lead on this. It sounds like an amazing design and don't count the little Fountec out just yet!!! :-)

Cheers!

[fjhuerta]

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

Hello Javi, if it is the frame chattering against the baffle it seems that more foam tape should certainly help. You might need a "tough" material like felt to prevent the frame lip from eventually cutting through the gasket.

Maybe test with one driver to get it the best you can, then rise and repeat for the remaining drivers!?!?

Yeah, that's what I'm going to do. Maybe add a 3rd layer of foam, just to be on the safe side. I believe it's a rattle. What's rattling - that's the question! If it's the enclosure I don't think I can do much about it.

It's going to HURT, though. ;) I'll also add tie wraps to the internal wiring and polyfill...

[fjhuerta]

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

This is the Vifa that Roger likely uses in this array - http://www.parts-express.com/vifa-tg...ange--264-1064

The paper cone Vifa is cheaper and a good performer... almost half the price of the one Roger uses. That's solid.

I'm still going with the Fountec. For the money it still seems like the value leader. I plan on mounting the drivers from behind... there just isn't enough room for them to breath and get solid hold from the screws with a front mount... just to small unfortunately. A little horn loading can't to much in this situation. Mine will be in an open baffle so I really hope to avoid the frame/seal issue altogether.

Thanks Javi for taking the lead on this. It sounds like an amazing design and don't count the little Fountec out just yet!!! :-)

Cheers!

You are welcome! I hope you have better luck mounting the drivers from behind. I should have followed your suggestion in the first place!

[fjhuerta]

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

I was succesful in fixing my distortion issues!

What I did.

a) Test each driver by finding out if there's voice coil rub.
b) Disassemble every speaker.
c) Add tie wraps to every single wire.
d) Glue the wire with quick expanding foam to the enclosure. Add foam to the terminal blocks.
e) Fill the enclosure at 100% with polyfill.
f) Add very thick weatherstriping to the lips of the drivers.
g) Assemble everything back.

That was a good 20 hours of my time...

But here are the results.

92 dB:

100 dB:

About 105 dB (I'm not sure, since it's only from 20 to 300 Hz and I had tons of non-linear response). It's probably closer to 110 dB. Things were starting to rattle around. And it's a BIG room.

So, the 100 Hz issue is gone and now I could properly integrate the speakers with a sub if I wanted to! I'm not sure I do, since bass improved by leaps and bounds. It's now tighter than it was before! I can feel the bass. Subjectively, it's louder and stronger than a speaker with a 10" woofer, that's for sure.

One other thing that happened: I did find out a damaged driver. One of the towers started distorting like crazy at 40 Hz. Since yesterday I had noticed that one speaker sounded very slightly different to the other. What happened is - there's a single driver with voice coil rub. Very slight, but once I found it I couldn't stop listening to it - worse, it was the one at 90 cms. tall! (basically, the one closest to my ear). I moved the cone and there was the rub. I'm replacing it today with the extra I bought. It's the only damaged driver out of the entire array.

Things are getting better and better

[Adam_G]

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

Glad you were able to sort it all out! Looks pretty solid for a $7 driver!

[fjhuerta]

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

Glad you were able to sort it all out! Looks pretty solid for a $7 driver!

Yeah. It sounds nothing like a $7 driver, either. At 100 dB, distortion around the upper midrange and treble area is close to -60dB, and looking at the 92 dB graph it makes me think it's close to the limit of my measurement system.

Then again, once you start adding up things, 7*51 = $357 in drivers alone, plus shipping, handling, the enclosure, assorted bits and pieces, and the MiniDSP or similar EQ. I'd say that, considering every part I used, it's close to a $1K speaker - not exactly cheap!

[fjhuerta]

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

Still testing the speakers, now with music. I re-EQ'd the towers and began listening.

Although they can do sine tones at very high levels, apparently 30 Hz - 38 Hz signals can sometimes cause the drivers to bottom out. It's a very rare recording that does this, and it's usually synthesized bass. But they can't handle very loud levels at those frequencies.

I've played with crossover settings and I'm trying to find a balance between bass extension and loudness. Honestly, it's at a level that I may not want to listen to long term.

This issue would be fixed by adding a beefy 15" sub. One side of my head tells me there's something magical about a 3" woofer handling pretty much everything with acoustic recordings or well recorded rock; the other side tells me Doppler distortion must be a major issue, with the little woofers moving so much at low frequencies.

The balancing act continues.

[Adam_G]

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

My mini-array has to be paired with a subwoofer, I've only got 8 per side, so the output below 100hz or so rolls off rapidly. I've got the sub crossed over at 90hz (as low as this one will go) and it pairs up very nicely!

[rmeinke]

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

Yeah. It sounds nothing like a $7 driver, either. At 100 dB, distortion around the upper midrange and treble area is close to -60dB, and looking at the 92 dB graph it makes me think it's close to the limit of my measurement system.

Then again, once you start adding up things, 7*51 = $357 in drivers alone, plus shipping, handling, the enclosure, assorted bits and pieces, and the MiniDSP or similar EQ. I'd say that, considering every part I used, it's close to a $1K speaker - not exactly cheap!

Wow... great work Javi!! sounds like you really have them performing well!!! Congrats man!!

[fjhuerta]

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

Wow... great work Javi!! sounds like you really have them performing well!!! Congrats man!!

I'm getting there! I still wonder about a sub. I guess sooner rather than later I'll add it.

Will you build your version? I'm curious!