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Multi-Way Conventional loudspeakers with crossovers

Line array prototype (with waveguide and CBT shading)
Line array prototype (with waveguide and CBT shading)
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Old 20th May 2017, 11:49 PM   #21
basreflex is offline basreflex  Spain
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with 3D printing you can design much better the conical to rectangular throat adapter, with constraints for equall path length and tapering. you need quite some 3D design skills. sketchup will not do the job...
I am considering building a 8ch dsp amp (similar do the nanaodsp board), so the delays can be designed to your linking as well as the shading
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Old 21st May 2017, 06:25 PM   #22
FoLLgoTT is offline FoLLgoTT  Germany
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Quote:
Originally Posted by Patrick Bateman View Post
I would use the same setup you did, except I'd use Aurasound Whisper instead of their 25mm driver.
I recommend using the Morel MDM 55. Sensitivity is much better than with the Aurasounds and it is not that much larger.

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What do you think? Is this worth doing, or do you prefer the sound of your newer projects?
Let me say first: I never heard my prototypes with a stereo setup. So I can't judge how good they really sound. They were just prototypes.

But the in-wall speaker we finally developed will be installed this year. Then I can tell more about how they sound.
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Old 5th October 2017, 06:15 PM   #23
Chris8sirhC is offline Chris8sirhC  United States
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interested as well. following
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Old 8th June 2018, 08:28 PM   #24
Patrick Bateman is offline Patrick Bateman  United States
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So I built one of these.

I have a pile of failed projects that I've never posted, and I thought this was one of them. I built it about six weeks ago, I measured it, and the measurements weren't so hot.

So I didn't bother to post anything online.

I put the thing on my desk to listen to it, and it's stayed there ever since. It's really remarkable how 'listenable' this thing is.

The thing I noticed in the first couple weeks was that it has really good midrange. I've built many Unity horns, and one of the places that I often stumble is when designing the crossover; if you're not persistent it can be challenging to get the midrange transition right.

This "CBT + waveguide" thing doesn't suffer from that; there's no crossover in the midrange, It Just Works.

After a couple weeks I liked it enough that I added an EQ into the mix to flatten out the response. That improved the sound.

Around the same time, I flipped the array on it's side, to see if it would work horizontally instead of vertically. It actually worked better, so that's good. On it's side, the treble is a little more consistent and extended.

My "clone" of FoLLgoTT's design is using this driver:

Tectonic Elements TEBM35C10-4 Miniature BMR(R) Driver | Medley's Musings

This driver has exceptionally low efficiency. I personally believe that most drivers are limited by xmax, and this driver has a lot. So my thought is that this driver might perform better than expected, because it has so much displacement. This turned out to be true; I am listening to the speaker as I type this, and while listening to it play a podcast, I can actually feel the speaker shake the desk (with voice!) And my desk is built like a tank, it weighs about 200lbs. These little drivers can move some air if you use enough of them.

About the only "X Factor" here is that the treble doesn't sound like a tweeter does. I need to do some more research on this. The high frequencies are equalized to be flat, but they don't sound like a dome at all. It doesn't sound "bright" it actually SOUNDS like it's rolled off a bit, but it's not. This is probably some directivity artifact that I need to research. (Perhaps the power response is falling?)

But I'm not complaining here, this thing is REALLY easy to listen to. In fact, the main reason I haven't built a second one is because I'm now leaning towards building a BIGGER one.


Click the image to open in full size.
Here's the phase and frequency response, measured ground plane outside. Like I said, not a good looking measurement. The phase looks great. These things have that 'articulation' thing going on that Unity horns and full range speakers do real well. I listen to a LOT of podcasts, I basically have them on 40 hours a week while I write software. Being able to get the midrange right is really important to me, far more important than bass or treble.

Click the image to open in full size.
Here's the frequency response and distortion. I'm using power tapering on the CBT, so it was surprising how loud this thing could get.



Last but not least, I forgot to mention:

I started out with the power tapering set up sothat the loudest drivers were in the CENTER of the array. I eventually switched to what Keele does, where the driver at the END of the array has the most power. The latter works better; it measures better and it also allows for a wider stage. (My CBT waveguide thing is on it's side, not vertical like FoLLgoTT)

Last edited by Patrick Bateman; 8th June 2018 at 08:34 PM.
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Old 9th June 2018, 08:17 AM   #25
lbstyling is offline lbstyling  United Kingdom
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Hi Patrick,
I have always found your posts interesting....
Have you seen Bob Carvers take on CBT?

YouTube

(Part 1 of 4)

He likes the sound to image from a center point quite high up.
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Old 9th June 2018, 10:17 AM   #26
wonderfulaudio is offline wonderfulaudio  India
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Hi Patrick,

Eager to know a few details. Pls share a few photos of vertical as well as horizontal array. How did you implement the active part and delay? Whats the vertical size, horizontal size, CBT beamwidth angle and waveguide beamwidth angle? For vertical array, it looks like you are using a ground plane CBT, the desk serves as a reflection which doubles the effective height and lowers the pattern loss frequency, both good things. For horizontal array, its not clear how its a CBT, since you said you are using the end driver with the highest power (ie a ground plane CBT) but with no ground plane (or side wall) to give the reflection.

Thanks
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Old 9th June 2018, 11:52 AM   #27
wesayso is offline wesayso  Netherlands
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Quote:
Originally Posted by Patrick Bateman View Post
About the only "X Factor" here is that the treble doesn't sound like a tweeter does. I need to do some more research on this. The high frequencies are equalized to be flat, but they don't sound like a dome at all. It doesn't sound "bright" it actually SOUNDS like it's rolled off a bit, but it's not. This is probably some directivity artifact that I need to research. (Perhaps the power response is falling?)
I have never, ever listened to a live performance and thought: hey, this top end sounds like a dome tweeter.
In fact, after playing with arrays for quite a while I don't think I want my top end have a sound like a dome tweeter. I've listened to a small near field setup with Pro monitors and was amazed at how much high frequency fuzz there was. It wasn't distracting as such, I just needed some time to get used to it again. But it never struck me as sounding right.

The coherence an array is capable of is way more important to me, personally. However FIR correction might bring your top end into play. If the driver has a clean top end, as you get what you put into an array back on steroids.
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Last edited by wesayso; 9th June 2018 at 11:56 AM.
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Old 9th June 2018, 06:01 PM   #28
Patrick Bateman is offline Patrick Bateman  United States
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Quote:
Originally Posted by wonderfulaudio View Post
Hi Patrick,

Eager to know a few details. Pls share a few photos of vertical as well as horizontal array.
I need to do that. It looks very similar to OPs

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Originally Posted by wonderfulaudio View Post
How did you implement the active part and delay?
I physically curved it. I designed it in 3D, printed it in 3D, and each element is 'splayed' by six degrees. A total curvature of 30 degrees.

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Originally Posted by wonderfulaudio View Post
Whats the vertical size, horizontal size, CBT beamwidth angle and waveguide beamwidth angle?
The laptop I designed it with was stolen by a hobo so I'll have to do these numbers from memory:

Vertical and horizontal size is about 16" x 16", similar to the waveguide in my old Summas. Vertical beamwidth is 30, horizontal is 90, but it's currently flipped on it's side. The CBT beamwidth is 30. (five units, each unit splayed six degrees.)

Quote:
Originally Posted by wonderfulaudio View Post
For vertical array, it looks like you are using a ground plane CBT, the desk serves as a reflection which doubles the effective height and lowers the pattern loss frequency, both good things. For horizontal array, its not clear how its a CBT, since you said you are using the end driver with the highest power (ie a ground plane CBT) but with no ground plane (or side wall) to give the reflection.

Thanks
It's in my office and my office desk is in a nook. So the waveguide-cbt thing is stuck in a corner.
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Old 9th June 2018, 06:04 PM   #29
Patrick Bateman is offline Patrick Bateman  United States
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Quote:
Originally Posted by wesayso View Post
I have never, ever listened to a live performance and thought: hey, this top end sounds like a dome tweeter.
In fact, after playing with arrays for quite a while I don't think I want my top end have a sound like a dome tweeter. I've listened to a small near field setup with Pro monitors and was amazed at how much high frequency fuzz there was. It wasn't distracting as such, I just needed some time to get used to it again. But it never struck me as sounding right.

The coherence an array is capable of is way more important to me, personally. However FIR correction might bring your top end into play. If the driver has a clean top end, as you get what you put into an array back on steroids.
Yeah it's really disconcerting. TBH, my Summas did that too, and I'd always assumed that it was because they roll off at 16khz. I figure that the missing output from 16-20khz was that "sparkle."

But this array goes out to 20khz, has no sparkle.

I wonder if constant directivity loudspeakers might require a 'tipped up' treble?
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Old 9th June 2018, 07:25 PM   #30
Patrick Bateman is offline Patrick Bateman  United States
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Quote:
Originally Posted by lbstyling View Post
Hi Patrick,
I have always found your posts interesting....
Have you seen Bob Carvers take on CBT?

YouTube

(Part 1 of 4)

He likes the sound to image from a center point quite high up.
Interesting stuff. Carver is now using power tapering.

YouTube

discussion begins at the 0:10 second mark
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