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I'm not posting much but reading much much more.
English isn't my native language so sorry if I'm not clear in my words now and then
But I want to share something in this topic...
I have a BK lfe for years now and it was fun but not satisfying. I was running it with a bke 1000 amp and a LFE signal from my denon x3500.
But it's a bit noisy when it's getting a small amount of power and not really shaking yet.
Weird thing is that in my old couch it was working much better. But that couch was far heavier than the one I have at this moment.

A couple of months ago I found a 2nd BK lfe and since my amp is capable of powering 2 of these I decided to buy it and right now i have 2 of these in my 2seater coach. That alone was a good upgrade. Not that one isn't enough but now it's more massive and even shaking the couch.

I came along this topic and the topic about the movie bass eq and then i decided to fit my behringer fbd (which i still had from the old days) between the x3500 and the bke amp.
I gave it a 8 or 10db boost at 20hz and that alone was amazing! Stunning!!
But the thing is, the bfd can't tune below 20hz and hasn't shelve filters so I bought a 2nd hand minidsp 2x4hd.
That did the trick! I'm experimenting with different filters and lpf's. Djeez this is a difference I never dreamt of!!
Wow, this is a difference of night and day!

I decided to take the BK's apart to see if I could modify something inside.
I contacted BK company but they couldn't help because that's what it is I guess.
I'll post later what I did to make them less noisier but now they are almost acceptable.
 

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This movie had some INSANE transients and some incredible wobbles, that even made the right (unoccupied) seat airborne!!! And slamming down on the sled again, making a clapping sound, LOL. Holy crap it scared the bejesus out of me, haha. Kind of the same problem as @SBuger, with no people in the seat, the HB is simply to much!! How the hell did we get there?? My seats are screwed to the MDF board under it, but that MDF just lays on top the the MA‘s in the rear, and it was here it got airborne, LOL.
I have all my seats screwed directly into the platform and they don't move or shake at all, only the reclining mechanism vibrates a little and the seatbacks flap around sometimes LOL:D

Screwing the seats down with MA's would't work very well, but maybe screwing down the front of the seats and use some double sided tape on top of the MA's could work;)
 
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Since it's becoming pretty clear that the 6dB/oct curves are just phenomenal on a lot of different devices, I wanted to graph it with the different companion LS filters that I've graphed in previous posts.

Obviously there are a lot of slight tweaks to these curves that can be created in between by changing the LS slightly, but I thought it would be helpful to see a lot of the different ones that I/we have messed with to see where they all fall relative to each other. In trying to hone in on the curve I prefer on my system, I had gotten really close, but I was on the fence between the red and green curves, which was either no added shelf or 10 2.3 0.5, so I decided to try something right in between, which is the blue curve (10 1.1 0.5). It turns out to be my Goldilocks curve, and that's what I'm sticking with. Kinda crazy that such a small difference is noticeable, but it most definitely is.


So, this graph shows the LS filter but not the other filters that make up the 6dB Oct curve, correct? So we need to combine to get the result displayed in the graph? Just wanted to make sure I understand.
 

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I won't take up the space with graphs or photos, but I took the tube out from between the speaker in the back of the chair and the chair cushion, measured 15Hz, then put that 16" tube inside the 22" tube under the platform (no speaker) and measured 15Hz.
Virtually no difference in harmonics.
The only other thing I can think to do is to go back to the "open" arrangement and see if that changes anything.
Not sure that's worth the effort (today ;)).
Michael
 

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Since it's becoming pretty clear that the 6dB/oct curves are just phenomenal on a lot of different devices, I wanted to graph it with the different companion LS filters that I've graphed in previous posts.
Since the 2x4 is unable to generate 6dB/oct curves, would it be possible for someone to calculate a biquad filter I can use instead? If I can. ;)
Thanks.
Michael
 

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Here is a Qvibe of the HB flat, with 10hz 6dB LPF, and with the LPF + your recommended LS.

Expecting the 9dB to drop more ;)
Just so you know, that 9.1dB LS was intended to be combined with the 11Hz 12dB/oct LPF:

LPF 10Hz 6dB/oct, LS 10Hz 8.0dB Q0.7, gain +3.5dB (for 9dB/oct curve add HS 20Hz -5.4dB Q0.7, HS 54Hz -4.6dB Q0.7)
LPF 11Hz 12dB/oct, LS 10Hz 9.1dB Q0.9, gain 0.0dB
LPF 10Hz 18dB/oct, LS 10Hz 9.0dB Q0.9, gain -0.5dB
LPF 10Hz 24dB/oct, LS 10Hz 9.0dB Q1.0, PEQ 15Hz 1.0dB Q1.0, gain 0.0dB
The 9dB/oct curve, which is what I thought at the time would give the flattest TR response based on the shape of your previous qvibe sweeps of MA only, was created by adding the two -HS to the 6dB/oct curve on the first line above. But then in a post a bit later, I theorized that since movie tracks typically have a built-in slope around 3dB/oct, the 6dB/oct slope would end up better.

But it's all good, since that post with all the different slopes the 6dB/oct slope has established itself as the ideal in my mind on MA/BOSS/HB setups, and I haven't run that 9dB/oct slope in a while. :) And as you noted, BK and BB are sort of different animals with their own wheelhouses.

Anyway, thanks for running all those tests including the distortion tests, and I'm happy to see you back up and running! :D
 

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Since the 2x4 is unable to generate 6dB/oct curves, would it be possible for someone to calculate a biquad filter I can use instead? If I can. ;)
Thanks.
Michael
I didn't realize it doesn't support 6dB/oct slopes. So 12dB/oct is the lowest it supports?

I should be able to make a pretty much perfect 6db/oct curve using shelves for you. I'll work on that today at some point.

Edit: According to what I'm reading, the 2x4 Advanced plugin supports "Butterworth up to 8th order (6 to 48dB/oct)"
https://www.minidsp.com/images/documents/Product Brief-2x4 advanced plug-in.pdf

If you can only go down to 20Hz with the LPF, then just use this:
LPF 20Hz BW 6dB/oct
LS 16Hz 4.2dB Q0.7
rolloff compensation filter
 

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So, this graph shows the LS filter but not the other filters that make up the 6dB Oct curve, correct? So we need to combine to get the result displayed in the graph? Just wanted to make sure I understand.
The graphs shows the 10Hz 6db/oct LPF combined with different single LS (shown in the legend). What are you referring to as "the other filters"?
 

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It may "support" it, but it's not an option; BW 48dB/oct is the only choice.
Filters go to 10Hz, no problem.
Shelves would be great.

Thanks.
Michael
 

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You can generate the biquad coeffs for a 1st order in beqd though
Sounds great if 1. I knew how to do that and 2. I could get beqd to run (I get a "file not found" error when I try to load anything, any version, any os, so I've given up).
I'll be happy doing it with shelves, though.
Michael
 

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Here’s mine. 6hz sine wave.

BB
I found this most interesting. Your BB is producing more at 24Hz and 30Hz than at 6Hz. I'm fairly certain that, without the harmonics, the TR would not feel as "natural."
Thanks for running that.
Michael
 

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I need help setting up my 3000 DSP before making measurements. I'm trying to dial in the LS6 10hz +4.4 Q.5 roll-off fix for the amp, but have run into a couple of problems. I first tried using the iNuke editor (v1.4) over USB to my computer to make the changes, but the app wouldn't connect (PC chimes there is a USB device plugged in though). I then went to the front panel menu to make the changes in the PEQ sub-menu. On the LS6 setting, I couldn't set the frequency below 20 Hz, and the granularity on the dB setting was 0.5 dB, so +4.5dB was the closet I could get. Any ideas?

Thanks,
Darrell
 

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I need help setting up my 3000 DSP before making measurements. I'm trying to dial in the LS6 10hz +4.4 Q.5 roll-off fix for the amp, but have run into a couple of problems. I first tried using the iNuke editor (v1.4) over USB to my computer to make the changes, but the app wouldn't connect (PC chimes there is a USB device plugged in though). I then went to the front panel menu to make the changes in the PEQ sub-menu. On the LS6 setting, I couldn't set the frequency below 20 Hz, and the granularity on the dB setting was 0.5 dB, so +4.5dB was the closet I could get. Any ideas?
Those filters are intended to be entered in a mDSP, not the iNuke. Do you have a mDSP?
 

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The roll-off fix is meant for an external device (specifically, one of the miniDSPs).
Try turning the amp off and back on again after the USB cable is connected.
Michael
 

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It may "support" it, but it's not an option; BW 48dB/oct is the only choice.
Filters go to 10Hz, no problem.
Shelves would be great.
If you drop down that box, what are the options? The HPF box below shows LR 12dB as an additional option.
 

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Ok, thanks. I have been using a combination of filters from the 9db curve without the LPF, so could I just add the single LS for the blue line for testing?
Yeah, you could just add the LS from the chart legend, then.
 
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