Next Project: Arc 40 CBT Array

[Millstonemike]

I was thinking of wrapping them in 2" mattress foam. It is going to be a nerve racking drive and if somebody decides to slam on the brakes in front of me I'll have two torpedoes flying towards the front of the vehicle. I'll leave plenty of room between me and the next vehicle to give me more time to stop just in case.

When loading a heavy object I always put it as far forward as I can (e.g., against back of seat, front of trailer, etc.). Then it can't get a "running start" during emergency braking. Easy on the acceleratioin and it will never move.

[Kevin K.]

Since these are going on the road - how will they be protected?

I was thinking of wrapping them in 2" mattress foam. It is going to be a nerve racking drive and if somebody decides to slam on the brakes in front of me I'll have two torpedoes flying towards the front of the vehicle. I'll leave plenty of room between me and the next vehicle to give me more time to stop just in case.

[Sydney]

Since these are going on the road - how will they be protected?

[Kevin K.]

What other project are you bringing? I'm assuming the esoteric and rs speaker? Anything else?

Yes, the Esoteric and RS will be one of them and then there's Kole's speakers, "The Black Widows"

[rickcraig]

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.

Yes, I think he'll be surprised on the bass capability of the array

I have a design with ten ND105's per side and with bass EQ turned some heads at shows with people looking for a subwoofer. The LT is just a single pole filter so if you want more headroom a simple 2nd order boost circuit works very well.

[rickcraig]

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

Hey Tom - I do remember Rory mentioning that. I had quite a bit of EQ to extend the bass so the little 2" driver at the bottom of the array was being taxed pretty hard. A high pass filter would help reduce the excursion and when I get a chance I will go back and revisit the design. As far as doing what Rory suggested it would be fairly complicated to implement plus it may even work against some of the positive things achieved by a CBT design.

[Navy Guy]

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.

What other project are you bringing? I'm assuming the esoteric and rs speaker? Anything else?

[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.

[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

[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.

[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.

[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

[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.

[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.

[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.