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Discussion Starter · #1 · (Edited)


This is a continuation of the discussion in this thread. There was some further discussion here as well. My current low end setup, chronicled here, consists of 8x LMS Ultra 5400s in sealed enclosures with 4x FP14000 powering them, pictured below. Kind of absurd to upgrade, but that's what this project is about. I feel the sealed enclosures I built left a lot on the table under 40hz that I can pick up by going with a vented alignment. A full build gallery is available here.

The outer dimensions of the new enclosures measure 48" long, 46" high, and 30" deep. Ports will be oriented on the sides as I will be stacking these. These dimensions were chosen mainly to fit in the current space that I have, stacked two high.

I've got two of these built, and I consider it a great success. It output as modeled, though the tuning ended up around 14.7hz, with an effective port length of about 55". I'm going to pick up some more lumber once the roads here are dry. The output from these down low is just so much greater than the sealed boxes. It would take four of them to equal one of these at 15hz. The bass from the ported boxes also feels like it has more impact. You feel it a great deal more in your chest. To make up for the lack of ULF I decided to get some Crowson transducers for my couch, which also add a great deal of tactile feel. Since this setup is on a slab, the ULF from the subs basically does nothing aside from causing my walls to flex an doors to bounce around. I can listen at lower bass levels now with more feel while having more headroom in reserve. Watching previous demo scenes and listening to various bass heavy music so far have me convinced this was the right move.

Since completing all four of these, I am incredibly happy with the results. EQ'd the same the bass is far more visceral and I have a lot more headroom where I needed it.

Bracing was accomplished with strips of left over ply from the build. Handy since it was almost all cut to size already. The boxes are painted with Duratex. Holes filled with spackle.

Sketchup file: download
Cut list: download

Original setup. The new enclosures will be stacked in the same place as the old.


Here is the project half-way through. Can't wait to finish. I can't describe how imposing these are, they still look kind of like toys in the picture, but those are 8' ceilings.


Modeled at 6200w with 13.5hz 3rd order butterworth highpass. I ended up using a 14hz 4th order filter. Very similar results.

Compared to the sealed subs with 8000w input and 11hz 3rd order filter (I have massive room gain in this area, filter prevents over excursion below 7hz). Both of these signal levels push the subs to almost identical excursion levels.



Excursion:


Port Velocity:



Enclosure:

It weighs about 400lbs with the drivers in it. This was built from maple ply, which was excessive, but the selection was poor when I went out to get the lumber for this. The second was built out of some not-so-good 6 ply soft wood sort of like arauco, but worse. It warped really bad and made my life miserable. Thankfully I have a lot of clamps. I found some nice Baltic Birch for $40/sheet that I'll be using for the last two.














Results, as modeled. Huge gains. It's hard to move these things. This was back-to-back with a sealed enclosure in the same location. No changes otherwise. This measurement was taken with a faulty mic. Apparently I shocked it one too many times or something and it was rolling off way sooner than expected. The gains are the same, but the slope is all wrong.



impedance



And in room results. There's a null at 80hz where the mic is placed. What's crazy is I still have headroom.



And full system results with XT32


3 Sweeps to determine compression... I can't measure louder with the umik1.

100db to 126db. Interesting how the walls react
Unstacked


Stacked


THD @ reference level. Mic is compressing/clipping


THD @ OMGWTF level. I think I might be am definitely reaching the ceiling of the mic's limits. I'm afraid to test louder for fear of damaging something in my house.

 

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Not

I know I keep repeating myself but I am really looking forward to the finished results


Thanks for sharing/documenting this whole process
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by Fatshaft  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_100#post_24318241


Not

I know I keep repeating myself but I am really looking forward to the finished results


Thanks for sharing/documenting this whole process

Come to the dark side
 

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Quote:
Originally Posted by notnyt  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build#post_24318298


Come to the dark side

Oh I am!

I guarantee it !!!

I can't before the summer. I don't have a garage.


I'll meet you on the dark side then

Reserve me a spot .
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by Fatshaft  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_100#post_24318364


Oh I am!

I guarantee it !!!

I can't before the summer. I don't have a garage.


I'll meet you on the dark side then

Reserve me a spot .

Excellent!


The transducers are awesome as well if you need something to hold you over until it's warm
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by LTD02  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_100#post_24318852


great plan. great work. great post.


how did you get sub 2 on top of sub 1?

Lifted it
I had the help of 3 friends.


The fun part was inserting some foam rubber draw liners between the subs after they were up there. Duratex on Duratex makes an awful noise. I had to lift the top sub solo for that.
 

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I have to ask... since you have what I presume is enough swept volume and power to listen to any audible frequency at more than sane levels, did you ever consider playing with a linkwitz transform on your sealed system? You could have emulate your modeled ported response curve easily enough, which should give the same "feel" changes you describe. Drawbacks being more input power required (you have plenty of this in reserve), and lower max possible spl (does that really matter in this case?).


I guess I don't understand unless it is for max spl bragging rights. The benefit of massive sealed displacement is that your final output response can be user adjusted to taste electrically while remaining louder than tolerable. You had that, but sacrificed it for an option that locked in one response and with significant size penalty. Do you really intend to listen now to 20Hz at 160dB instead of 150dB?
 

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Discussion Starter · #12 ·

Quote:
Originally Posted by Bigus  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_100#post_24318910


I have to ask... since you have what I presume is enough swept volume and power to listen to any audible frequency at more than sane levels, did you ever consider playing with a linkwitz transform on your sealed system? You could have emulate your modeled ported response curve easily enough, which should give the same "feel" changes you describe. Drawbacks being more input power required (you have plenty of this in reserve), and lower max possible spl (does that really matter in this case?).


I guess I don't understand unless it is for max spl bragging rights. The benefit of massive sealed displacement is that your final output response can be user adjusted to taste electrically while remaining louder than tolerable. You had that, but sacrificed it for an option that locked in one response and with significant size penalty. Do you really intend to listen now to 20Hz at 160dB instead of 150dB?

You might be pulling some of these numbers from your nether regions, or possibly just exaggerating to try to make a point. I'm not sure which. My sealed setup was EQ'd flat, with the -3db point at 7hz. I was bottoming out the subs during movie and music playback somewhere in the 15-20hz region. My ported setup is EQ'd flat down to around 14hz, but I have the headroom now to not worry about bottoming out my subs. I don't have any room gain in that area and there's 10,000 cubic feet of open air space to deal with. I wouldn't be busting my ass building these just for bragging rights, there are plenty of other ways to get louder output.


Also, level matched and EQ'd the same, the ported subs have a different feel to them. Can't quite explain it, but it's there, and I like it.
 

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Quote:
Originally Posted by notnyt  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build#post_24318926


You might be pulling some of these numbers from your nether regions, or possibly just exaggerating to try to make a point. I'm not sure which.
Exaggerated, not to make a point but as a tip of the hat. I don't recall exactly what your max levels were, but I know it was loud. Really loud.
Quote:
My sealed setup was EQ'd flat, with the -3db point at 7hz. I was bottoming out the subs during movie and music playback somewhere in the 15-20hz region. My ported setup is EQ'd flat down to around 14hz, but I have the headroom now to not worry about bottoming out my subs.
Man, hard to believe you were bottoming 15-20Hz in real world usage, but I'll take your word for it. Not sure if that is due to the large space or insane listening habits (both), but I suppose that is a legitimate reason to go chasing more headroom in that range. I would have never guessed that... figured it was just a response curve preference kind of thing.
 

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Quote:
Originally Posted by Bigus  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build#post_24318947

Quote:
Originally Posted by notnyt  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build#post_24318926


You might be pulling some of these numbers from your nether regions, or possibly just exaggerating to try to make a point. I'm not sure which.
Exaggerated, not to make a point but as a tip of the hat. I don't recall exactly what your max levels were, but I know it was loud. Really loud.
Quote:
My sealed setup was EQ'd flat, with the -3db point at 7hz. I was bottoming out the subs during movie and music playback somewhere in the 15-20hz region. My ported setup is EQ'd flat down to around 14hz, but I have the headroom now to not worry about bottoming out my subs.
Man, hard to believe you were bottoming 15-20Hz in real world usage, but I'll take your word for it. Not sure if that is due to the large space or insane listening habits (both), but I suppose that is a legitimate reason to go chasing more headroom in that range. I would have never guessed that... figured it was just a response curve preference kind of thing.
 

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Discussion Starter · #15 ·

Quote:
Originally Posted by Bigus  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_100#post_24318951



Exaggerated, not to make a point but as a tip of the hat. I don't recall exactly what your max levels were, but I know it was loud. Really loud.


Man, hard to believe you were bottoming 15-20Hz in real world usage, but I'll take your word for it. Not sure if that is due to the large space or insane listening habits (both), but I suppose that is a legitimate reason to go chasing more headroom in that range. I would have never guessed that... figured it was just a response curve preference kind of thing.

Ah, somewhere around 130db at 20hz depending on position in the room was what I was peaking at iirc. Less under there as excursion starts skyrocketing. They'd bottom out during WOTW and HTTYD pretty bad without pushing it to insane levels. If I pushed it in some movies with not as deep bass, they'd still bottom. Pushing it listening to electronic music with sweeps down to a bit under 20hz also bottomed out before being able to reach the levels I wanted. Giving up content under 14hz to have the extra output is definitely worth it to me. The transducers I added deal w/ that pretty well anyway, since I'm still feeling it. In fact, more so than previously. Granted, I won't feel the room pressurize with a 10hz sine wave like I did before, but that was only something I'd ever notice when testing with signal generators anyway, or starting the Xbox.


It's really worrying to hear the LMS drivers bottom out, especially after seeing pictures of what happens. Things like that can keep you awake at night



I basically had the choice to double up on drivers for 3db, or to redo the enclosures for 10-12db where it mattered. I went with the bigger enclosures. At least I'm not losing any more floor space =]

 

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Wow, that's very interesting to hear that you're bottoming them around the 15-20HZ region.

My 21's bottom at around 20HZ region too...one of my 21's makes a knocking noise (pretty bad!) when it's close to bottoming. that's when I know it's at their limit.

The other 3 don't make that noise.

OTOH, my SI18's can take a hell of a beating and have problems bottoming them out.


Can't wait to start on my end too.

I'm just gonna have to beg someone to tell me what size a cab I need for my 21's...
 

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How are you guys bottoming out these massive 18" & 21" subs at just 20hz? Something isn't right with your enclosures or system setup because those drivers should be able to do 15hz to 20hz with ease!
 

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Quote:
Originally Posted by Martycool007  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_50#post_24319301


How are you guys bottoming out these massive 18" & 21" subs at just 20hz? Something isn't right with your enclosures or system setup because those drivers should be able to do 15hz to 20hz with ease!

Very easy...by applying MAJOR power

Sorry...don't know what else to tell you.


My 21's are getting roughly 2100Watts per sub

My 18's are getting roughly 1250Watts per sub


I believe that's a lot of juice and I know it's way more than they are rated for.

Someone correct me if I'm wrong.


I DO NOT blast sinewaves loud at them.

This is during movies ONLY that they bottom out! Never on music!


Examples:

Monument scene in OLF

Rocket launch (Ender's Game...this one really bottoms HARD!) at approx 1:05:00 mark.
 

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Discussion Starter · #20 ·

Quote:
Originally Posted by Martycool007  /t/1516234/8x-18-lms-5400-ultras-sealed-to-27-cube-15hz-ported-build/0_100#post_24319301


How are you guys bottoming out these massive 18" & 21" subs at just 20hz? Something isn't right with your enclosures or system setup because those drivers should be able to do 15hz to 20hz with ease!

The EQ necessary to get a sealed enclosure to play flat causes massive excursion increases, not much else to it.
 
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