Next Project: Arc 40 CBT Array

[Millstonemike]

I tend to play from my current play list

+1. It will allow you to ascertain performance quicker by playing what you already know.

They look stunning.

[---k---]

Wow. Amazing work.

[Derekj]

Beautiful! Well done Kevin.

[Kevin K.]

Thanks for the kind words Fellas!

I should have been more specific when asking for good Demo CD's. John's suggestions was what I had in mind, something with good sound effects and or imaging to demonstrate with. As for music, like you guys said, it's more of a personal taste thing and I doubt we would find something that everyone would agree on. After reviewing the Recommended test tracks link Sydney provided, it looks like several of my favorites were recommended by other members; Eagles, Dire Straits, Fleetwood Mac, Pink Floyd.

No run time on these yet Sydney. But you do bring up a good point, I wonder how long it will take for the woofers to break-in/loosen up so to speak. Since the arrays are shaded, I'm guessing it will happen in stages, bottom bank first, followed by each subsequent bank.

[tomzarbo]

You know Kevin,

it doesn't seem like something anyone is working towards, but I keep thinking about Rory's comment back in the hotel the evening after last year's MWAF... Regarding the smaller arrays that you built the cabinet for....

The jist of it was...

it would be interesting if you could just "shade" the directional output of the woofers while leaving the low (non-directional) frequency output un-attenuated. In other words, get the full bass effect from the upper drivers while toning down what needed to be toned down for it to work as a shaded array.

I thought it was a genius idea at the time and I still do... though I have no idea how difficult that would be to pull off... even with DSP and all those tricks.

I just wonder what all your woofers could do if they were all working 100% in the lower registers! With the small array in the hotel room, you could see visibly that the upper drivers were not moving as much as the lower ones. Maybe with your larger array it wouldn't be so pronounced?

At any rate, they look crazy good and I'm wondering if I'll hear them in Southern, New Jersey when you fire them up!

TomZ

[Kevin K.]

Thanks Tom.

Perhaps Rick will chime in and we can see what he thinks on Rory's comment. If I was guessing, allowing the woofers to all play lower frequencies "un-shaded" while "shading" the tweeters or higher frequencies would cause the arrays to sound thick(not sure if that's the right word for it) as you moved closer to them, kind of like taking a speaker that has full BSC built into the crossover and mounting it in a wall. One of the amazing things about the CBT arrays is their ability to sound the same from near or far and I believe you would lose that if you did what Rory was talking about. Maybe I'm way off base here and have everything confused, not difficult for me to do, trust me.

[Millstonemike]

No run time on these yet Sydney. But you do bring up a good point, I wonder how long it will take for the woofers to break-in/loosen up so to speak. Since the arrays are shaded, I'm guessing it will happen in stages, bottom bank first, followed by each subsequent bank.

I'm sorry I didn't mention this before. From building a sub a few years ago, I read that breaking in a woofer was best done in free air using its resonant frequency with little power (so as not to exceed xmax). I guess it's too late now unless you remove some drivers and tap into the individual woofer connections.

[Kevin K.]

I'm sorry I didn't mention this before. From building a sub a few years ago, I read that breaking in a woofer was best done in free air using its resonant frequency with little power (so as not to exceed xmax). I guess it's too late now unless you remove some drivers and tap into the individual woofer connections.

I'll bring em up slowly and give them plenty of playing time at moderate levels before pushing them. Thanks Mike.

I've often wondered if "break-in" was more for subs then woofers or mids since the surrounds are so much thicker/stiffer on subs.

[Navy Guy]

I'll bring em up slowly and give them plenty of playing time at moderate levels before pushing them. Thanks Mike. I've often wondered if "break-in" was more for subs then woofers or mids since the surrounds are so much thicker/stiffer on subs.

I just manually push the cone in and out to xmech a few times before measuring. That is usually sufficient.

[jhollander]

You can frequency taper. I can't recall the article, but it's similar to a 2.5 where you cascade inductors. I had a design with the ART array for a frequency taper. For us passive guys XSim makes it easier to do the sim.

[tomzarbo]

Thanks Tom.

Perhaps Rick will chime in and we can see what he thinks on Rory's comment. If I was guessing, allowing the woofers to all play lower frequencies "un-shaded" while "shading" the tweeters or higher frequencies would cause the arrays to sound thick(not sure if that's the right word for it) as you moved closer to them, kind of like taking a speaker that has full BSC built into the crossover and mounting it in a wall. One of the amazing things about the CBT arrays is their ability to sound the same from near or far and I believe you would lose that if you did what Rory was talking about. Maybe I'm way off base here and have everything confused, not difficult for me to do, trust me.

I have NO idea what I'm talking about with arrays, so I'm probably not talking realistically about it. I just understood what Rory was saying and it sort of made sense to me at the time. You're planning on 'subbing' it in the future anyway so it's a moot point I guess. Just thinking out loud.

TomZ

[Kevin K.]

I have NO idea what I'm talking about with arrays

TomZ

You and me both! I'm just building em, Rick is the audio guru and I'm just the lowly tech trying to pick up on a few things along the way. The subs will happen down the road but it would be nice to have a little punch from these until then.

[bcodemz]

You and me both! I'm just building em, Rick is the audio guru and I'm just the lowly tech trying to pick up on a few things along the way. The subs will happen down the road but it would be nice to have a little punch from these until then.

With 20 5'' woofers, this is equivalent to having 5 10" woofers of the same Xmax, or about 2 normal Xmax 10'' woofers. Since this is powered by a miniDSP, you can easily apply a Linkwitz Transform to extend the bass considerably, and they should give plenty of bass (~105dB) before running out of excursion.

Rory's idea is easily doable on the miniDSP, but requires some work to do well. The main problem is the need to steeply ramp up the low frequency to match the lower woofers without affecting the lower midrange, and a way to dial back the bass without reducing the midrange when the volume level starts to approach the woofer's limits. The latter is not really an issue if you don't listen very loud, but this speaker just begs to be cranked.

[JavadS]

Wow Kevin, just getting caught up, stunning! I know you are loving that feeling you get when you finally start bolting in drivers and can stand back and admire it is reality what has only been in your imagination up to this point, love it!

Can't wait to hear these, you're bringing them to MWAF right?

Javad

[Kevin K.]

Wow Kevin, just getting caught up, stunning! I know you are loving that feeling you get when you finally start bolting in drivers and can stand back and admire it is reality what has only been in your imagination up to this point, love it!

Can't wait to hear these, you're bringing them to MWAF right?

Javad

Thanks Javad, how true that is, loading the drivers was the most exciting day of the build. They were a lot of work and seemed to have taken forever but I couldn't be happier with how they turned out. Are they perfect, Nope, but maybe how they sound will make up for some of the flaws in the cabinet work. I really look forward to sharing these with you guys this summer and barring a blizzard in July, they'll be there along with a couple of others projects.