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@a77cj7 , I'm almost done with 2 more V5 builds. If I remember correctly, putting 2 pillows inside was yielding better results? I'm assuming any pillow (something cheap from Wallmart) would do? Also where do they go? I think in the area that's b/w bottom rail and back rail? That's the only space available so that must be it :)
 

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Hmm, been looking for something that would pair with my horn-loaded La Scala IIs for awhile, would make use of my DS115-4s. Why did you model with the 8 Ohm?
The potential builder has an 21DS115-8, so the model is based on that. He is also using DCIs so the resistance is not a big point.
 

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@a77cj7 , I'm almost done with 2 more V5 builds. If I remember correctly, putting 2 pillows inside was yielding better results? I'm assuming any pillow (something cheap from Wallmart) would do? Also where do they go? I think in the area that's b/w bottom rail and back rail? That's the only space available so that must be it :)
Cheap Walmart pillows are great. Ideal location is on the side panels not obstructing the vent. See the JBL Quad thread from Chris.
 

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@a77cj7 , I'm almost done with 2 more V5 builds. If I remember correctly, putting 2 pillows inside was yielding better results? I'm assuming any pillow (something cheap from Wallmart) would do? Also where do they go? I think in the area that's b/w bottom rail and back rail? That's the only space available so that must be it :)
As John indicated, check out the quad build for my testing. Wally world pillows work fine.
The 40” cabs may only need one pillow, I haven’t measured.

Chris
 

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As John indicated, check out the quad build for my testing. Wally world pillows work fine.
The 40” cabs may only need one pillow, I haven’t measured.

Chris
Cheap Walmart pillows are great. Ideal location is on the side panels not obstructing the vent. See the JBL Quad thread from Chris.
I bought 4 pillows just in case. How do you make sure it doesn't move around the box in case box is moved up and down? I'm assuming you glue it up?
Will check out the thread

Update: Went through the thread and found pillow on page 10. Instead of gluing, I'll staple the pillow. Here are the images with 1 and 2 pillows in the box. Should I put 1 or 2?
With 2 pillow and putting a bracing, it won't touch the driver edges.

3076653


3076654
 

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I bought 4 pillows just in case. How do you make sure it doesn't move around the box in case box is moved up and down? I'm assuming you glue it up?
Will check out the thread

Update: Went through the thread and found pillow on page 10. Instead of gluing, I'll staple the pillow. Here are the images with 1 and 2 pillows in the box. Should I put 1 or 2?
With 2 pillow and putting a bracing, it won't touch the driver edges.

View attachment 3076653

View attachment 3076654
1 should be fine in a 40” cab. I don’t have measurements to back that up YET.

However, I do have this from my 40” cabs:


You can see the cab resonance around 150hz. (No pillow) That is safely above a 80hz crossover anyway. I always intended to open them back up and add pillows, but never did before they were sold.

I will add a single pillow to my new 36” cabs. I’ll add a second if measurements show any issues

EDIT: It looks like the plastic is still on the pillow in your pic. Definitely remove it if you haven’t already.

Chris
 

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I stapled my pillows in place, simple, cheap and easy. In general the shorter the longest dimension of the cabinet, the less damping (pillows) you need as the resonant frequency continues to move higher the shorter it gets.
 

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With my narrow mini devastator
18" driver
Baffle driver wall. 20.5/35"
12" top
12" side
To mark center ?


Front chamber rails notch them 1 "
No, 18” drivers are 10” down from top of baffle for driver center.
Center driver in baffle width. If your baffle is 20.5” wide, center is 20.5/2 = 10.25”.

I like notching rails 1.5-2”, for pressure equalization on the driver. Not sure how much it helps.
Here’s my latest minis with a 2” notch. Ignore open front, these are windowed cabs.


Chris
 

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What started as a cute end table Micro Stepped Devastator has somehow turned into a sub with design goals similar to the SKRAM. Here is a snap shot, sim is the 21DS115-8 chugging along on 3400 watts of power. Velocity is around 30m/s on the vent with a BW 25Hz 2nd order HPF active. For music this thing would definitely tickle.

View attachment 3076275
Is this in the index yet?

Juju
 

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Discussion Starter #2,392

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1 should be fine in a 40” cab. I don’t have measurements to back that up YET.

However, I do have this from my 40” cabs:


You can see the cab resonance around 150hz. (No pillow) That is safely above a 80hz crossover anyway. I always intended to open them back up and add pillows, but never did before they were sold.

I will add a single pillow to my new 36” cabs. I’ll add a second if measurements show any issues

EDIT: It looks like the plastic is still on the pillow in your pic. Definitely remove it if you haven’t already.

Chris
I stapled my pillows in place, simple, cheap and easy. In general the shorter the longest dimension of the cabinet, the less damping (pillows) you need as the resonant frequency continues to move higher the shorter it gets.
I already have 4 pillows now. Do you see any issue if I put both in? Does pillow only get rid of the resonant frequency??? I think I read a while ago that someone put pillows in and reported that it made the bass punchier.
 

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I already have 4 pillows now. Do you see any issue if I put both in? Does pillow only get rid of the resonant frequency??? I think I read a while ago that someone put pillows in and reported that it made the bass punchier.
Probably won’t hurt much. Could lose a bit off the left corner.
The pillows are just to control the rear chamber resonance. No change to rest of response.
Here are measurements of the quad:



You can see excessive pillows or poor placement hurting the left corner, but no other effects except for resonance control.
The two pillow measurement was effectively blocking port. Both staggered and standing are also two pillows in better configuration.

You could add the other pillows to your other mini devs.

Chris
 

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Probably won’t hurt much. Could lose a bit off the left corner.
The pillows are just to control the rear chamber resonance. No change to rest of response.
Here are measurements of the quad:



You can see excessive pillows or poor placement hurting the left corner, but no other effects except for resonance control.

You could add the other pillows to your other mini devs.

Chris
haha. I don't want to loose left side. 1 Pillow it is. Yeah I can do that. The front V5 don't have pillow in them. But they are sitting on top of a stand I built. I have been planning to replace that stand so I guess I'll be killing two birds with 1 stone.
 

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Discussion Starter #2,396 (Edited)
Bass Ascension Module Five (BAMF 21")

This cabinet found its inception in a end table Micro Devastator that got out of hand when I tried MBM mode on the rear chamber. The pass band is clean to the high 100s for resonance. Application - music or PA duty. The main simulation is on the 21DS115-8, I am including 2000 watts simulations on the other popular options. The active high pass filter is a BW 25Hz 2nd order. 1 watt sensitivity through the passband is about 97db.

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1000 watt normalization with 21DS115-8

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2000 watt simulations

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SAN
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NSW6021-6
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21DS115-4
3077662


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Window frame cutouts (remaining material is 1.5")
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Vertical bracing spacing
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3077666
 

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so is anyone getting 30db swings in their eq? im +12 at 20hz all the way to -15 at 90 on a finalizer v2 and still am not quite there, i dont have rew set up and have just been measuring db by 5 hz increments and adjusting so i might be a little inaccuate.

the other thing i think is factoring in is that the finalizer v2 has a higher resonance peak at 90-100, and the nsw6021 seems to naturally come up around that point as well.

just wondering if im doing something wrong haha
 

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so is anyone getting 30db swings in their eq? im +12 at 20hz all the way to -15 at 90 on a finalizer v2 and still am not quite there, i dont have rew set up and have just been measuring db by 5 hz increments and adjusting so i might be a little inaccuate.

the other thing i think is factoring in is that the finalizer v2 has a higher resonance peak at 90-100, and the nsw6021 seems to naturally come up around that point as well.

just wondering if im doing something wrong haha
You need to get REW running. What your room is doing to the response is very different from the native response of the cabinet. It won’t be a nice smooth curve.

Chris
 
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