# Custom RE XXX Subwoofer Build



## funky_waves

And there was a stack of plywood and Bubinga; Soon to become a 25 cubic foot custom enclosure for a Resonate Engineering 18" XXX Overall dimentions of 66"tall 41.5"wide 22" deep with a downfireing 10" port system designed by the customer, to tune to ~11hz. More pictures will follow.


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## Ricci

:yay: 
It's finally happening!

Nathan if you pull off this craziness with the quality of your other work I've seen... You will truly be the man!

That solid Bubinga looks nice too...


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## ISLAND1000

I like saying . . . . Bu . . . Binga . . . . slowly in my lowest voice. It's sounds like I'm on safari.


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## Mike P.

Will this be a "side firing" tube?


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## Ricci

Nay say I...twill not be a tube at all. That cavernous cardboard tunnel pictured is for the exhaust from the 80lb air pumping device. This to be housed in the laminated flesh of dead birch and bubinga trees. :dumbcrazy:


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## Mike P.

After looking at the pic again you may be right.


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## Ricci

I may be right indeed...it's for me that this monstrous construct of bassitude is to be created.


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## Mike P.

Lucky you! So what's the net volume and tuning going to be?


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## funky_waves

And the router said "Let there be holes" Net volume will be 25cubic feet tuning should be 11-12hz


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## ISLAND1000

Nathan . . . . you've got me conflicted. On the one hand I'm a "tree hugger" on the other hand I'm a neo-subist. After I saw all that debris from all those holes you drilled through my beloved Bu . . . Binga I have decided I can't watch anymore. I'll wait to hear how it sounds.


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## Ricci

Are those line array cabs in the left hand background?


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## funky_waves

Ricci said:


> Are those line array cabs in the left hand background?


They are not full line arrays, 9 midbases and a ribbon tweeter.

More progress pics;


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## Ricci

Wow! Looks like you are really kicking butt on this thing. Those last 2 pics had me cheesing while I stared at them. The internal bracing looks great. Judging by that lathe picture maybe you should contact Mike Rowe from Dirty Jobs!


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## Owen Bartley

First of all, wow that's a crazy amount of complicated looking bracing. And second, there's a lathe involved in this project!? You always have to kick it up a notch, don't you Nathan! I can't wait to see the finished result on this one. Keep us updated!


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## MatrixDweller

I'm wondering what the lathe is making for the sub? Must be something good. I can't wait to see the finished project. It looks like you are a skilled craftsman Nathan.


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## Ricci

Using the lathe, Nathan is making what I presume to be the port flow guides. Here is a rough concept that will help you get the idea...


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## MatrixDweller

That's pretty cool...thanks. There's nothing like dedicated hand craftsmanship. I would suppose that anything mass produced would use cheap plastic.


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## Owen Bartley

Yeah, it really adds a lot of character to the project. I forget who made the tunable sonosub with a similar adjustable wood "spike" built into the port. I'm loving these advanced projects.


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## MatrixDweller

Do the materials available have a huge impact on the final result? 

For example if the flow guides, ports and internal bracing were made out of aluminum, other metals, hardwood, softwood, MDF, particle board (LDF) or hard plastic (polycarbonate or acrylics). 

Is it all about mass/density and vibration dampening characteristics?


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## Ricci

I gave Nathan a pretty tall order with this sub enclosure. First off it's huge! 25 cu ft after subtracting for bracing, driver and port system. Also it is not a normal ported sub, the port system is much more complicated than just a port in a box. Actually I don't know for sure that it works as described by the patent holder. I'm just assuming that it does:sweat:, since they had it patented, used it in their products and had technical write ups in mags. Also I opted to go for a premium finish(bubinga like my drumset)look at the snare drum in my avatar) and I had pretty strict dimensional limitations. There are a lot of other details too. It's a big project and I'm really anxious to see it come to life as he builds it. 

Concerning the materials used...Some are better than others for certain applications. I really dig the small solid aluminum enclosures that Nathan has done, but for this application imagine the weight! It would be impossible to move! Actually we decided to use Birch ply for this mostly because it would save some weight over MDF. I think that we are estimating the enclosure to be about 300lbs:flex: without the 80lb driver in it!


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## MatrixDweller

380lbs...holy smokes! I guess you won't have to worry about it dancing over the floor. I can't wait to see the finished project. I'd love to hear it but I think I might be able to feel it from here! The bubinga finish should look amazing. I love the ornate wood finishes used on musical instruments. :bigsmile:


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## Owen Bartley

I don't know how much the materials matter, I think the quality of construction is more important... as long as the materials are actually up to the task. And with 300 lbs of plywood and sweet sweet bubinga, and with Nathan doing the work, I have no doubts at all that this project will be!


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## mdrake

WOW..... all I can say is WOW and WOW. That is some really nice craftsmenship!!!
Can't wait to see the finished result, that bubinga wood should look bomb! 380lbs, I hope Nathan owns a forklift. :bigsmile:

Matt


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## Ricci

Nathan probably does! I on the other hand don't! :sad:That's why it will have casters and handles.


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## Mike P.

I can imagine what the shipping will be to get that monster to your door!


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## Ricci

Regarding the cost of this thing, shipping, etc...All I will say is :spend:


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## mdrake

Do you have a pic of the woofer that is going in this box? :bigsmile:


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## Ricci




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## mdrake

WOW that is big! What Brand of woofer is that? I have never seen anything like that!!! :bigsmile: Thanks for posting that!

Matt


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## Ricci

It's a Resonant Engineering(RE Audio) XXX 18. Like the thread title states:T.

Nathan,
It's been a few weeks...anything new to report? I'm trying to be patient!


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## mdrake

Oh, :bigsmile: I figured the XXX was where the model number was supposed to be.

Matt


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## MatrixDweller

Ricci said:


>


That almost looks like some sort of a shrine. Add a few candles and/or some incense and the "god of thunder" might appear.


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## Ricci

LOL! Nah it's just the bar area of the house where I live. We'd just had a little get together. It's a little "eccentric" around here:coocoo:.


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## Owen Bartley

Wow, that is one giant driver. The basket and motor structure look almost comically big! I keep scrolling back up to look at it... and it looks like it should be attached to some industrial machinery or something... it just looks so powerful and serious.


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## funky_waves

Here is another pic for you, just before the front went on, the inner flow guide installed.


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## Mike P.

Nice job on the bracing!


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## Ricci

Looking good Nathan! The pic of the bracing and the flow guide are great. I'm going to send you an e-mail shortly, just wanted to go over something with you. 

Guys when you look at the pic of that port keep in mind that is a 10" sonotube. The driver is an 18 that actually measures 19". I just picked up a second one:jiggy: .


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## MatrixDweller

I think you're going to get noise complaints...from houses a couple miles down the road. That thing's going to be a beast :scared:.


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## Owen Bartley

So Nathan, does the flow guide work better than a flared port by itself to reduce chuffing, or does it have something to do with tuning as well?

Josh, I hope you have some help ready to move your final project... with 2 of those monsters it's going to be heavy!


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## funky_waves

It is suposed to be at least as good as a large flare, but it is also suposed to lower the tuneing for a given port length. I have never biult a sub with this port design so I am not sure how well it accualy works. looks good in theory.


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## Ricci

Owen,
This cabinet is for only 1 subwoofer. If I like the way this turns out, maybe I will commision Nathan for a duplicate later on. Yes it will be a bear to move. 

The port is based on a design that is patented and was made available for DIYer's. I have never had a sub that uses this port system either so we are kind of taking a shot in the dark with it. I have faith thoughraying:. There is a lot more discussion of it in the thread that I started called "My RE XXX18...What to do with it?" It's in DIY Subs Sealed and Ported. I don't feel like typing all of that out again. I'll bump it up for you.


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## Owen Bartley

Awesome, thanks Ricci. I'll go and have a read, it seems pretty interesting. I think it will be hard to make a poor sounding sub out of this equation. Even if you guys don't' manage to get to the theoretical maximum of the design, I'm sure it will sound great.


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## funky_waves

Here are some more progress pictures.

In the last picture in case you can't see I am behind my son Josh, yes inside the subwoofer standing up:bigsmile:


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## Ricci

Sweet Bejeebus that's big:blink:! I mean I knew how big it would be, but actually seeing it in scale is...whoa. 

How old is your boy Nate? Mine just turned 3. Good times.


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## ISLAND1000

Yikes!


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## Ricci

Wait a minute. I thought that you were joking about standing in the sub, but now that I look closer I think I see a shoe. You were serious!?


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## Blaser

What is very interesting is the port design. Is it a variable area port? if so how does it work? Was screwing achieved by turning? Pls explain


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## ISLAND1000

Ricci said:


> Wait a minute. I thought that you were joking about standing in the sub, but now that I look closer I think I see a shoe.


You gotta be "Joshing" me . . . . . with all that bracing he's got in there he'd have to be a contortionist to be able to standup inside that dual side by side sarcophagus. I believe what you might be seeing is one of his wife's black jewelry boxes. The young boy does like baubles just like his Dad. LOL


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## Ricci

blaser said:


> What is very interesting is the port design. Is it a variable area port? if so how does it work? Was screwing achieved by turning? Pls explain


Blaser,
The port system is based on one devised and patented by Polk audio in the mid nineties. They had a nice write up about it in Audio magazine(RIP) in MaY 96 and offered a simple calculator that they had devised for it and other plans for people to DIY the port system with. Basically the principle is that you increase the port mouth area through expansion and lower the tune. It supposedly offers much better laminar air flow capability and since there is no straight line path to the outside of the enclosure it also helps with port resonance. See the 2 pics below the first is a normal port and the mouth is highlighted green. The second one is this design and the mouth is now the entire circumference of the area highlighted in red and green. 
















Everyone I discuss this with seems to say "Oh that's nothin special, I don't understand how it's going to accomplish that,or it's just a waste of time". Normally to tune a 10" vent to 11hz in an enclosure this size it would be 62.5" long. This vent, if it works as proposed will accomplish, that same tune with a straight length of only 36.5" and at the same time increase the port area at the mouth to the equivalent of a 14.8" diameter port. I've read the patent papers and am confident it will work. Also have you ever heard of placing your ports close to a panel to get a lower tune? Many of the top sub designers will use this technique( the EPIK Conquest and SVS Ultra13 both do). So much for keeping your ports at-least one circumference from any walls huh? I think this is also involved here with the distance of the disks. It is more than I can explain. If you really are interested have a look at the patent papers.

5,517,573
5,809,154
7,162,049


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## funky_waves

Josh is 15months, Here is a better pic of my legs, if you look at the picture of braceing there is the front hole and above that three large holes in the braces that line up almost straight to the top. My head is a little bent though I am a little taller than the 60"s inside.


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## ISLAND1000

Well I'll be darned . . . . there you are, deep inside the tuned portion of your project!


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## Blaser

Ricci said:


> Also have you ever heard of placing your ports close to a panel to get a lower tune?


Standard design normally wants at least 1 port diameter to be left from all sides for the port to breath. Otherwise the tune will be decrease (that's what you mean) but port noise may occur (obviuosly not in this design).



> Many of the top sub designers will use this technique( the EPIK Conquest and SVS Ultra13 both do). So much for keeping your ports at-least one circumference from any walls huh? I think this is also involved here with the distance of the disks.


OK. So it seems it is not for variable tune purpose but to decrease port length.... OK.


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## Ricci

By the way this is what Unibox predicts for this sub...Not too bad:yes:. Also ignore the lowest port resonances. The special porting system used should not have these.


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## Mike P.

Josh, how long until the sub is at your place?


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## Ricci

I'm not real sure:scratchhead:. Nathan is still working on the cab. I believe he's got the basic structure done and now he's doing the veneering and wrapping things up. I've sent him one of the 18's and it should arrive at his place on the 22nd. From there hopefully he'll be ready to mount it and do some listening tests before getting ready to ship it. The shipping is probably going to be at-least 10days. 

I guess I hope to have it by this time in June.:huh:


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## vinculum

That thing is a monster, Ricci! I hope you have good relations with the local law enforcement agents!

One thing if note, while the port is physically 10" in diameter, you are occupying the cross section width with another cylinder of wood. Typical 10" port rules no longer apply. It will model as a smaller diameter port with an enormous flare. Not a bad thing! 

Dr V


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## funky_waves

The port area left is equal to a 9.375"dia port. and if the tuneing is what has been predicted the overall length including the flow guides will still be less than a 9.375" port would need to be to tune to the same frequency.


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## Ricci

The projected peak airspeed is right at 35ms at 10hz with the port area readjusted as a 9.375" unit. This is at full on peak output though. I doubt that there will be problems with chuffing or port compression. The huge flares and the flow guides should take care of buisiness.:newspaper:

A regular 9.375" port would still need a straight pipe of 55.75", compared to 36.5" for this design.


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## Blaser

Ricci,

This is not to mention that typical program material will be better represented by RMS velocity as opposed to peak.


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## funky_waves

Here is the latest pictures, one of the baseplate and one of the sub upsidedown, the last of the corners being glued in.


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## Blaser

That's one big beautiful sub :T


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## Ricci

Man that looks pretty good Nate! Not quite as dark as I thought it would be, but it looks nice. I bet it was easier to test mount that top assembly with out the motor on it. 

This is gonna be one big, professional looking, overbuilt, over-engineered, monstrosity of a sub.


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## funky_waves

Remember the wood will get a bit darker when clearcoated. it is going to be nice for sure.


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## Ricci

I think I'm going to have to name this thing...


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## funky_waves

Finished, less the grill. Tuneing landed ~11.5hz.


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## Ricci

That looks really good. I can't wait to see...wait... experience it in person. If ever a gimongous subwoofer cab could look good, this is it. I'm still stunned by those spl readings down low too.


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## Blaser

EXCELLENT! I would like to see an actual FR at LP :bigsmile:


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## Ricci

Blaser,
Look in the Battle of the Monsters thread located here in the FunkyWaves section. Nathan tested the max spl output before audible distortion and also took a frequency response measurement. It's at his place and not mine though.


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## Owen Bartley

It looks awesome... and man is it intimidating! I like the handle too, that just seems to take it to another level of saying "I mean business!". The enclosure makes the woofer look tiny, which is no small feat!


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## Ricci

Looks like this Behemoth is going to be shipping out, with the Dual SDX15 sub that Nathan built for me for winning the giveaway contest, today. I'm stoked:R. It's going to be hard to wait the week or so that it's going to take to recieve them. Look for lots of listening impressions and pictures when I get them. I'll also do some testing down the road, but I have to get a new laptop first. 

Excuse me while I double up on my work-out regimen, in preparation for massive subwoofer wrestling sessions to come.:flex:


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## Blaser

Ricci said:


> Excuse me while I double up on my work-out regimen, in preparation for massive subwoofer wrestling sessions to come.:flex:


Good luck!:bigsmile:


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## Ricci

The sub is sitting in my living room and it is beautiful. The packaging was stellar with nothing out of place what so ever. I can't fire it up until tomorrow. I have to get Speakon cables. It is gigantic and I only put one small ding in it getting it in the house(doorway. not a big deal), which is not bad considering the size and weight of it and the fact that it was just me and one other guy.


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## Owen Bartley

Congratulations Josh! It must be very exciting getting a new toy like that. You know we want to hear your impressions once you get it going, but we also want more pictures!! Do you have this monster in a corner, or is it out in the open?


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## Ricci

I finally replaced my USB cable for my Olmypus and got time to post up some pics, so without further adeiu...

Here's the crate with love from Canada...




















Here's some shots taken during the dismantling of the crate. The packaging was first rate.










































Here's a shot right after we got both of the subs into the house that illustrates the size and girth of the XXX subwoofer cab. I'm the darkly tanned guy on the left:rofl2:!

















Here's a shot of the SDX sub shot during one of many recuperation periods. As you can see it's no lightweight mini-sub either! See that staircase...yes it was a PITA. Thats my sister in the picture. The one with orange hair.


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## Owen Bartley

Wait... what!? Where did the SDX come from? It's beautiful! Why don't I remember anything about that one being built? What kind of wood is it? The grilles look awesome too, I love how Nathan does those.


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## Ricci

I won the FunkyWaves sub giveaway. That's the option that I picked. Dual sealed SDX's in 8ft. The finish is Makore.


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## Owen Bartley

Oh yeah, that's right!! Grrrr... I think that was my option! :hissyfit:

Lol, just kidding, it really looks amazing, I'm glad it turned out so well, and I hope you'll have it on display somewhere it can be appreciated! Congrats on both new units!


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## SAY IT LOUD

Awsome job that sub looks great and no doubt packs a punch. Now all you need is a big screen cheers Troy


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## Ricci

Some pictures of the power port...cavernous.Kindly diregard the cables everywher and the clutter. I have to clean that up later.



























This is a look up into the power port. You can see the inner flowguide. This is one giant port. 










More pictures to follow soon.


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## Ricci

Here's a few shots of the sub in it's final resting place. Excuse the clutter. Cleaning hasn't been my highest priority lately!


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## Mike P.

I'm dying to hear what your impressions are of both subs! :yes::yes:


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## Ricci

Well alright. Here's what I've got so far. Keep the following in mind: I did set the level to be about +3db hot relative to the monitors. I have not yet measured the room response or the response of the sub. I don't have a working lap-top now so I can't run REW. That will be remedied soon. Also since I have not had a way to accurately measure things there is no EQ'ing being done yet either. What I have right now is the raw response of the sub in the room, my senses, test tones and a Galaxy CM-140.

Overall it sounds good! Its clean, extended and effortless. Compared to my 2 Velodyne CT-150's it replaced, I think it sounds better. It does sound different though. Honestly it sounds like someone added one of those harmonic bass synthesizer's that adds an extra octave of low bass to the system. It just sounds so much deeper and more like a real bass event even with music. This is all at low to moderate volume. I've got it crossed at 80hz, but I may move to 60hz eventually.

From the small amount of listening I've done so far I would guess that I've got a null maybe 2 somewhere in the upper bass 50-70HZ and a natural house curve starting around 35hz on down due to room gain and the extended response of the sub.


I did get on it for momentarily with some Bass Mekanik stuff and the Twitchy Sines track from ROE and it was very impressive. The low stuff was literally shacking the entire house to the point where I was asked to stop. I've got a lot of rattles and stuff to eliminate. I'll have the house to myself for a bit this afternoon, so I'm going to take the CM-140 and get some readings.


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## SAY IT LOUD

WOW what a MONSTER is that your bedroom or are your using a bed as a lounge? I am buildind a 200 ltr twin 12" modelled from the svs PB plus 2 i will post pic when finished. That is the largest sub i have ever seen for home theatre. Now all you need is a 500 inch screen to match your sub. Cheers Troy Down Under


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## Ricci

It's the living room and we use it for lounging. I don't do the interior decorating around here, unless you count the electronics and speakers everywhere.:R


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## Ricci

Ok let me just say that there is no need of a highpass with this system at all and that the low frequency output below 20hz is like nothing I've ever heard. The excursion that the XXX is capable of is insane. I'm inclined to believe what the RE Audio tech's told me about the mechanical limits being somewhere north of 60mm. It's downright retarded. Also the amount of air that the powerport is flowing down around 14-8hz is huge. The entire area between the bottom of the cab and the baseplate is acting like a giant slot port. ******* huge slabs of air coming out.:devil:

I don't need a highpass at all because I've definitely got some roll off in my signal chain. Everything seems fairly good down to 9-10hz and then it starts rolling off and seems to be roughly 12 to 14db down at 5hz comparatively. Remember this is just guesstimation, but it's based on the excursion of the driver at the same levels, which should be way unloaded at 5hz and getting out of hand. 8hz seems to be where the roll off in my signal chain really kicks in. I'll try to measure this when I get a new laptop.

I did take some output measurements, but they are not max-output spl's per se. The Crown never batted an eye and the XXX just kept displacing more air. Honestly I kind of chickened out because the forces involved here are really crazy for one driver and I didn't want to damage anything. I never heard the driver beg for mercy or start to sound bad. The room and house started sounding bad first. At one point a big picture fell off of the wall and a glass in the next room vibrated off of the counter and broke.I didn't know until I walked into the kitchen. Also at 15hz and 16hz the DIY chase thats in the pictures started jumping off of the floor. The left corner was jumping up and down:hide:. I basically took it up to a point where I didn't feel comfortable going any louder due to the driver excursion, fear of clipping the amp or things were falling off of the walls... literally. I may push it a bit harder at some point but honestly I can't really even conceive of a movie hitting those kind of sustained levels and music will be amp limited( doubt I'll be listening at those sustained levels either). I had to cut things short because my girl got back from shopping with my sister and said something to the effect of "quit it!".


After taking into account the CM-140 correction factors. I was able to attain an easy 115db+ at every frequency from 20hz down to 10hz. I just left the volume at -12db and proceeded up. There was some variation with levels up to 119.1db recorded at 17hz. There is definitely more gas in the tank in the 10-20hz octave and my floor joists apparently resonate at 13hz:hsd:.

At 5 hz The CM-140 showed 105.1db when I quit increasing the volume. The correction value at 5hz is 24db. Giving a reading of 129.1db. Can this possibly be right:dunno:? I mean it was seriously flexing the room at that point and I will say that it felt kind of like the earthquake tremor we had awhile back here. At 6hz the Galaxy showed 103.1db and the correction factor is 18.8db.a total of 121.9db apparently???? 7hz was 104db + the correction of 16.09db for a total of 120.09db. These are the levels when I didn't feel comfortable increasing the volume any more. I guess I have the magic 30+db of gain below 8hz that Bossobass talks about? ****. I don't know.

I do know that Nathan's description of it sounding like a back hoe is assailing the building is pretty accurate. Also that 10hz is not as hard to hear as people make it out. I can easily sense the really low stuff at moderate volumes.

I'm going to have to take some video's at some point.


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## Mike P.

But are you happy with it? Just kidding! :bigsmile: Having that amount of low end output makes it all worth while. Kinda brings new meaning to the term "effortless bass", doesn't it? :T


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## Ricci

Mike P. said:


> But are you happy with it? Just kidding! :bigsmile: Having that amount of low end output makes it all worth while. Kinda brings new meaning to the term "effortless bass", doesn't it? :T


I'm really happy with it:yay:. I've watched 10000B.C., Neurosis: A Sun that Never Sets and The Incredibles so far. It really delivers the goods when called to do so. I'm simply hearing bass that my old Velo's couldn't produce, since they gave up pretty much at 25hz. I can't wait to get REW and get it EQ'd to be even better.

I'm going to try WOTW, Finding Nemo, or Cloverfield next.


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## funky_waves

So far of all the movies I have tried for testing the Leviathan scene in Atlantis, is the best for sub 20hz bass, the opening scene is very good too, as well as several other scenes throughout. I highly recomend it for testing. WOTW was fairly good too, there are many. FOTP was very good as well.


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## Ricci

I'll look into Atlantis and the other tracks that you mentioned Nathan. You should check out the Fireworks demo thats available on the Danley website. It's got crazy dynamic range on it. 

Did you ever hear any port noise out of this thing when you tested it? I've yet to hear anything at all. I just don't see being able to hear anything during normal material.


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## Ricci

Here are 2 frequency response measurements taken at the 2 primary listening positions. These are raw and there is no smoothing, or EQ applied and the 80hz x-over in place. They were taken with REW, a Turtle beach SRM soundcard, ECM8000 mic and Xenyx 1202 mixer. Overall I'm really happy with the response I have and I'm not going to use EQ. :T




















This is a close mic'd response of the driver that shows the 11.5hz tuning notch in the response. The crossover is set at 150hz here, which is as high as it will go.


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## Ricci

More measurements 

--------------------------------------------------------------------------------

Here are 2 power response graphs I took last night using REW at the main 2 listening positions. I was trying to look at power compression, or port limiting effects. I started at a 95db nominal sweep level and increased the drive level by 5db on my Outlaw processor for each sweep. I ended with a 115db sweep level. The sweeps were from 7-200hz with a 1M file size and lasted 22 seconds each. The 80hz 24db octave SW crossover is engaged. There were no signs of driver distress, or amplifier clipping at the nominal 115db sweep levels, but it was loud. I believe that there may be enough headroom for a 120db sweep. I would've tried to take a sweep at that level, but I ran out of headroom in the input signal chain with the settings I had. I would've had to recalibrate to a higher level and start the process over and I already did that twice trying to get the headroom for a 115db sweep. I will do this again at a later date. The driver's minumum motion notch was clearly seen during the sweeps. 

Try to keep in mind that I'm no Finnish subwoofer tester and my equipment is very basic compared to a real test rig. The first 2 sweeps also had what REW termed as a very low input level.


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## Ricci

Here is a new set of measurements using a shorter sweep. I think it's about 5secs. Much shorter than the grueling 21.8sec sweep used in the last set. The highest level sweep is IT. That's everything that this system can give when doing this sine sweep. The shorter sweep allowed a bit higher levels, but as you can see there is a lot of compression going on at 9-11hz and 30-50hz(???). This is at the ragged edge of things. The system is amp limited technically, but I don't think that any more power would get much more out of the driver. The amp actually tripped the breaker on the surge protected power strip that it's plugged into once and self protected twice when trying to determine the max sweep level. The amp is none the worse for wear and driver took all of that drama in stride.


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## BrianAbington

looks nice.


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## Ricci

I did some distortion tests yesterday. They were taken from the main listening position, which is across the room about 4 meters away. The test frequencies are 64, 50, 40, 32, 25, 20, 16, 12.5 and 10hz. I didn't sit there and try to calibrate each measure to some predetermined level. The level of these tests for each frequency is reflecting the affects of the room on the FR and also the subs FR to a lesser extent. I just set the sweeps to a certain level and ripped through them.



64hz, 102.5db















50hz, 106.5db
















40hz, 105db















32hz, 107.5db


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## Ricci

25hz, 110.5db
















20hz, 110.5db
















16hz, 108db
















12.5hz, 110db
















10hz, 108db


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## Ricci

Here's a set at a much higher level. I didn't want to push things much harder as this is with one driver facing the wrath of a 4ohm bridged CE4000 dumped into it with pure sine waves. These tests aren't exactly quick either, as it takes a few seconds for the distortion levels to get calculated and level off and then another few seconds to freeze the measurement and stop the sine wave. Gotta be careful with this kind of test. 


64hz, 109.5db, 3.821% THD

















50hz, 113db, 4.264% THD
















40hz, 110.5db, 3.533% THD















32hz, 114db, 5.183% THD


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## Ricci

25hz, 116.5db, 4.816% THD















20hz, 118db, 16.65% THD
















16hz, 116db, 19.7% THD
















12.5hz, 118.5db, 5.7% THD :hsd::hide:
















10hz, 113.5db, 13.93% THD :hsd::flex:


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## Ricci

I'm continually impressed with this sub. I know I've said it before but the <25hz output from this is monumental. I would consider this a great performance distortion wise. There is a lot more output available at 40, 50, and 64hz (maybe 10 and 12.5hz too)than what I tested at here. The distortion levels at 16hz and 20hz are highest because this is where the driver has the highest excursion, since it doesn't fully unload below tuning until about 8 or 9hz. I knew this would happen and it is a trade of that you make when you choose to get a super low tune. I still consider the fact that the THD never reaches 20% at the worst case scenario area of 16 and 20hz with levels this high to be exceptional IMOP, especially considering that the driver excursion was about 3" p2p or maybe more at those 2 frequencies. Also I think that the 10hz distortion reading may be a bit high. I may not have allowed the reading to fully average out, which would result in a higher reading. Had to quit as it was getting late and the GF was getting VERY irritated:foottap:. I never heard any port noise with these tests. Overall it sounded very clean. I thought I detected a bit of strain or change to the tone at 16 and 20hz but it's hard to say because it was shaking everything in the house. Definitely wouldn't have heard anything with normal material.

Now to figure out what to do with the other 3 drivers I have... :dumbcrazy:


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## Toolatecrew

No wonder she was irritated. 113 db at 10hz?? He insides probaly felt like they were in a paint mixer. That thing is just sick.


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## Ricci

Hey! She was supposed to be gone most of the afternoon. It's not my fault she came home early while I was in the middle of testing!


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## funky_waves

No figuring required, you know what to do :bigsmile: I smell a quantity discount..........



Ricci said:


> Now to figure out what to do with the other 3 drivers I have... :dumbcrazy:


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## Ricci

Actually I may be in contact Nate. I'm trying to decide whether to buy another driver and run 4 of them sealed and use the big ported monster for a secondary HT system, or just run 2 sealed and have another of these built. It's tempting...120db from 10hz up should = done. I've got to take care of some other stuff first and recharge the account too though.:T


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## Ray in Kingwood

Absolutely awesome. I enjoyed this


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## epereira

That is a HUGE beast! I am so very jealous but the neighbors already hate me and I don't even try to be loud :bigsmile: I hope you are in a well sound-proofed house or have the local police over often for movie nightsaddle:


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## bigsausagepizza

I know this was years ago, but I have a question if anybody is still following this.

When using the pwrport spreadsheet, what did you use for the external disk diameter? You effectively used the entire bottom plate for the external disk, and I'd like to do something similar. It doesn't seem to make too much of a difference, but I'd like to know what you used if you remember. I'm thinking of using this design in a car sub tuned low, it would really help with minimizing port size and length.


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## tesseract

Hopefully we can get an answer to your question, but just noticed your gear which made me miss my NAD 1020 and Hafler XL600.


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## bigsausagepizza

tesseract said:


> Hopefully we can get an answer to your question, but just noticed your gear which made me miss my NAD 1020 and Hafler XL600.


Yeah, the NAD to Hafler combo is a good one. I can't imagine what you could do with an XL600, the 200 with my TLAHs I've never gotten much past half volume.


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## bigsausagepizza

It's on. I've purchased a DSS Ethos 12" from Direct Sound Solutions and will be attempting this port design for my car. I plan on running about 1.5 cu ft and tuning around 30hz. The manufacturer suggests 40 square inches of port area, which produces an extremely long port (for a car at least). I'm hoping to be able to shrink that considerably with this design.

Thanks again for the build and info on this design. I'll link to a build thread when I get started.

Here's the sub: http://www.directsoundsolutions.com/ethos-12-subwoofer-1800-watts/


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