Need help designing serious bass solution for a big theater..horns vs ported or both? - Page 2 - AVS Forum
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post #31 of 411 Old 07-27-2014, 11:51 AM
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The advice I took when in your position was to build a single horn with the biggest mouth I could get away with.
No regrets.
Use the box designs as inspiration, but you have enough room to build in a FLH that is ~25 foot long with ~ 100 ft^2 mouth, if you have the mouth behind the screen and are clever, the room becomes part of the horn and the mouth would be the other end of the room at >600 ft^2, and >50 foot long, That would be over the top.
Cheers
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post #32 of 411 Old 07-27-2014, 02:32 PM - Thread Starter
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Quote:
Originally Posted by Cortga View Post
The advice I took when in your position was to build a single horn with the biggest mouth I could get away with.
No regrets.
Use the box designs as inspiration, but you have enough room to build in a FLH that is ~25 foot long with ~ 100 ft^2 mouth, if you have the mouth behind the screen and are clever, the room becomes part of the horn and the mouth would be the other end of the room at >600 ft^2, and >50 foot long, That would be over the top.
Cheers
Cort


Hey Cortga, Thanks for dropping by and offering me some advice

Ok, I am trying to understand what you are saying. You are saying the mouth is what lowers the tune right ? But I am not understanding fully what you mean when you say the room becomes part of the horn ?

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post #33 of 411 Old 07-27-2014, 02:38 PM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post
max spl is similar to the dual sws15 configuration, 127db.*
OK... I have been practicing my HORNRESP KUNG FU

Now the next step is to check out this Alpine driver you are talking about so I can see if I can come up with what you are talking about.

http://www.alpine-usa.com/product/view/sws-15d2

This is the driver you are talking about right ? ^



http://support.alpine-usa.com/produc...01215_D4_2.pdf

SPECIFICATIONS

Power Handling
Power Range: 150W - 500 Watts
RMS Power Handling: 500W
Peak Power Handling: 1500W
Dimensions
Mounting Depth: 177mm (7'')
Mounting Diameter: 347mm (13.7'')
Displacement: 0.07 cu. Ft.
Added Volume: 0.15 cu. ft. (Reverse Mount, Magnet Out)
General
Frequency Response: 24Hz - 200Hz




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post #34 of 411 Old 07-27-2014, 02:51 PM - Thread Starter
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Ok first question for LilMike, MAX, LTD or whomever...

If I was starting to enter in values for the Alpine in HORNRESP what do I do for dual VC driver like this?

I was entering the D4 model.




Does that look right? Do I just enter in Re as single ? Or do I do something else with that field ?
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post #35 of 411 Old 07-27-2014, 03:08 PM - Thread Starter
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what does everyone use for the liters to cubic feet ?

1 liter = 0.0353147 cubic feet right? So do you just design in liters and then figure out cubic feet later ? or is there a parameter to change that ?


Also what size box should I start with for Vrc and Lcr ? Does it matter? If I just use 30 for the Vrc value that's like a 1.05 cubic foot box right? So what about this Lcr ? Lcr = Rear Chamber average length (cm). Does that mean how long before the flare or the horn starts inside like the initial area where the driver goes into ?

Does it matter what I use for that? Can I just use like a little more than the driver size ?

If I use : Vrc = 60 and Lcr = 50 That seem logical or bad?

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post #36 of 411 Old 07-27-2014, 08:49 PM
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these numbers aren't doubled check or anything, just a napkin sketch.
the parameters for the d2 and d4 may be a little different, I'm not sure.
I just happened to have the d4 entered for coils in series.
the response of the plot will be the same if the values are entered for coils in parallel.
in red OD (offset driver) is "2P" that is for DRIVERS, 2 in parallel.
otherwise, monkey around with s1, s2, s3 etc.
sd * 2 is 1560 or about 1600. s2 is 400. so the compression ratio is ~4.0:1
for eg, that is voltage, since the drivers are in parallel, enter 1w into 1/2 of Re, which is 3.5 ohms
if a value in the driver is different by a little, it may just be the way they were entered.
different ways of entering the parameters can give slightly different results.
my mmd is 267.66 yours is 267.69 for example. that kind of difference means nothing.
hope that gets you started.


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post #37 of 411 Old 07-27-2014, 08:52 PM
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Quote:
Originally Posted by Mfusick View Post
Ok first question for LilMike, MAX, LTD or whomever...

If I was starting to enter in values for the Alpine in HORNRESP what do I do for dual VC driver like this?

I was entering the D4 model.




Does that look right? Do I just enter in Re as single ? Or do I do something else with that field ?
Unfortunately, the spec sheest does not specify whether the params were measured with voice coils in series or parallel. Hard to say. Someone who has measured the driver can chime in.

JSS
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post #38 of 411 Old 07-27-2014, 08:52 PM
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28.3 liters per cubic foot, roughly
remember that the wood itself takes up considerable volume with something like this, so subtract off about 15-20% for that and a little more if the horn has air gaps at the corners for example. 20-25% total volume lost from external horn dimensions to horn resp model is a decent guess starting point.

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post #39 of 411 Old 07-27-2014, 08:53 PM
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Lrc I generally use a value 2x the diameter of the driver until I have a model and fold done, and suppress resonances when HornResp calculates...

JSS
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post #40 of 411 Old 07-27-2014, 08:55 PM
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So what about this Lcr ? Lcr = Rear Chamber average length (cm).


Lcr is the distance from the driver to the wall of the chamber behind it. just make it about 30cm, i.e. about 1 foot. it only matters for calculating reflections, which for basshorns are almost always way up and out of the passband.

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post #41 of 411 Old 07-27-2014, 09:04 PM
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"Unfortunately, the spec sheest does not specify whether the params were measured with voice coils in series or parallel. Hard to say. Someone who has measured the driver can chime in."


I'm not sure those parameters are sensitive to voice coil wiring. if the coils are put in series or parallel the derived parameters should scale and the horn performance will be the same. cms shouldn't change, re and le would be 1/4 of coils in series, bl would be half, etc. mmd, and the q's, vas and fs shouldn't change.

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post #42 of 411 Old 07-27-2014, 09:06 PM
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Once you get to folding, I updated the YouTube links for the basic folding tutorial:

Offset Driver Horn Folding Tutorial Using Sketchup

JSS
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post #43 of 411 Old 07-27-2014, 09:06 PM
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by the way, props on your initiative to tackle hornresp. :-)
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post #44 of 411 Old 07-27-2014, 09:43 PM
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Quote:
Originally Posted by LTD02 View Post
lilmike had noted that the alpine sws-15 worked well in a horn, I forget which one.


I modeled it up. after making a few adjustments here and there...my initial reaction was...you got to be kidding me!


the response is among the best that I have ever seen in a front loaded horn.


[EDIT: after looking at this again, my initial conclusion may have been driven as much by the sheer size of the horn and the positive effect that has on response as the driver itself.]




max spl is 'only' 127 db in the excursion limited zone at 15mm xmax, but unlike most drivers in the ultra budget category, this little guy has a damage point of 30 mm. the street price on the driver is something like $120.


mike, i think that we may have found what you are looking for!
^^^^^ Not sure if you were referring to me or not but you definitely got my attention!! I will be following this thread closely.

I better finish my 2nd full Marty before I tackle this build. And somewhere along the way, I have GOT to install the full monty of sound isolation (RSIC>hat channel>5/8"OSB>(GG>5/8"Drywall)^2) so I can listen to my system when my wife is home...

Mike
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post #45 of 411 Old 07-27-2014, 10:57 PM
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another option could be to build such a horn with bricks or concrete block.


many are familiar with this build, but many are not.


royal device, second sub featured:


http://www.noiseaddicts.com/2008/07/...-in-the-world/

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post #46 of 411 Old 07-27-2014, 11:52 PM
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Max were your napkin SPL ideas FLH design?


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post #47 of 411 Old 07-28-2014, 03:01 AM
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So has anyone come up with a specific horn based enclosure for the Alpine SWS-15? If they work as well in horn loaded enclosures then I may order a couple tonight, and wait on you guys to come up with a nice design! My priorities are mid-bass and cheat pounding bass, not super low extension.

So is there an existing high performance design for the SWS15 for someone with no size or space limitations? Ideally one that has max output in the 30hz to 100hz range?
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post #48 of 411 Old 07-28-2014, 03:53 AM
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Quote:
Originally Posted by Martycool007 View Post
So has anyone come up with a specific horn based enclosure for the Alpine SWS-15? If they work as well in horn loaded enclosures then I may order a couple tonight, and wait on you guys to come up with a nice design! My priorities are mid-bass and cheat pounding bass, not super low extension.

So is there an existing high performance design for the SWS15 for someone with no size or space limitations? Ideally one that has max output in the 30hz to 100hz range?
For mid bass and chest (I assume you meant chest?) pounding bass IMO you would want a higher cut off than 30Hz unless you were using a single cabinet solution solution for the bass. For optimal mid bass impact a straight horn is the best in my view, take a look at the old Martin 215 mk2, the Inlow sounds mid bass horns or the Funktion One DS15, these will all require a sub below them. Other designs that are not straight but are also good for this job are the Void Hyperfold or the Danley BC412 or the Noise Control RGW-112. There are various DIY designs for mid bass horns over at diyaudio and speakerplans, they tend to be more focused on horns than AVS DIY so you may have better luck searching their archives for ideas.
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post #49 of 411 Old 07-28-2014, 03:56 AM
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I might add that mid bass is particularly affected by the room, so no matter what you get setting them up right and treating the room is of great importance. Your mains and subs/midbass cabinets must be aligned properly to achieve the desired effects.
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post #50 of 411 Old 07-28-2014, 04:37 AM
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This horn was designed around a pair of the SWR-12D2:

Alpine SWR-12d2 Tapped Horn + Audio Memorial BBQ get together?

Sketchup files and other information in the thread. Picture of the folding does not have the drivers represented, but they both load the trapezoid shape at the throat, one is buried in the horn, the other you can see in the mouth.
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post #51 of 411 Old 07-28-2014, 06:02 AM - Thread Starter
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Wow! Nice to wake up and see all the replies

Just FYI I was in the middle of typing a nice reply with some hornresp screen shots last night when we lost power. Turns out some microbursts wreaked havoc on my neighborhood, trees down all over the place. I didn't even save my work so it's all been lost. I'll try again later today when I get a chance, power just came back.

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post #52 of 411 Old 07-28-2014, 07:39 AM
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Quote:
Originally Posted by Mfusick View Post
Ok first question for LilMike, MAX, LTD or whomever...

If I was starting to enter in values for the Alpine in HORNRESP what do I do for dual VC driver like this?
I can't help with the horn aspect, but I can recommend a very good dual voice coil FAQ from the Smith & Larson web site.
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post #53 of 411 Old 07-28-2014, 10:17 AM - Thread Starter
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Quote:
Originally Posted by Decadent_Spectre View Post
I might add that mid bass is particularly affected by the room, so no matter what you get setting them up right and treating the room is of great importance. Your mains and subs/midbass cabinets must be aligned properly to achieve the desired effects.
I am probably going with a larger woofer style SEOS design, and possibly a dual woofer design so midbass should be plenty without the need for the horns to go too high. I'd rather have a lower corner actually and cross them over sooner, since it's the lower bass I am most concerned with.

Is there any valid strategy in designed two horns, one upper and one lower ? Mixing them ?


Quote:
Originally Posted by Martycool007 View Post
So has anyone come up with a specific horn based enclosure for the Alpine SWS-15? If they work as well in horn loaded enclosures then I may order a couple tonight, and wait on you guys to come up with a nice design! My priorities are mid-bass and cheat pounding bass, not super low extension.

So is there an existing high performance design for the SWS15 for someone with no size or space limitations? Ideally one that has max output in the 30hz to 100hz range?
I am working on it. The trouble as the smart guys above explained already is that chest slamming midbass and ULF extension are different things. Also ideally I want both, which is what makes me wonder if I can do that with a singular design ?


Quote:
Originally Posted by LTD02 View Post
by the way, props on your initiative to tackle hornresp. :-)
Thanks !

But I still need help! (don't leave me hanging)

Quote:
Originally Posted by maxmercy View Post
Once you get to folding, I updated the YouTube links for the basic folding tutorial:

Offset Driver Horn Folding Tutorial Using Sketchup

JSS

Thanks ! I've been digesting a lot.

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post #54 of 411 Old 07-28-2014, 10:39 AM - Thread Starter
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Ok take a look at this:








School me up on how I should be thinking. Couple specific things I'd like to know is:

What controls the tuning ? How do I adjust the low corner up and down?

What controls the height of the peaks and valleys ? How do I smooth things out ?

Is there some kind of "auto calculate" way I could find the optimal result for a specific driver at a specific tuning ?
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post #55 of 411 Old 07-28-2014, 10:42 AM - Thread Starter
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Would fiberglass work for a FLH? Any advantage to making it more curvy than straight corners?

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post #56 of 411 Old 07-28-2014, 11:19 AM
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What's the reason you have a strict budget for drivers but unlimited funds for wood? Do you have access to free or super cheap wood or something?

At least if you spend most of your budget on drivers, and less on wood, they hold their value decently and have re-sale value. With large wood boxes, you won't get re-sale value out of those.

Looking forward to see this theater build, it seems like you have researched it an insane amount, so it should be amazing.


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post #57 of 411 Old 07-28-2014, 01:51 PM
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Quote:
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What's the reason you have a strict budget for drivers but unlimited funds for wood? Do you have access to free or super cheap wood or something?
Also curious about this. It's a basshorn dream come true (if true).
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post #58 of 411 Old 07-28-2014, 01:57 PM
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So you have about 8000 cu.ft. of space. Of that how much could the riser use?

If it was 14", then you could try to fold some good basshorns in there.

14" x 16' x 23.5' = 438 cu.ft.

You could fit two optimal (200 cu.ft.) LAB12 basshorns in there. Each should be capable of 130db(ish) down to 20Hz or below on about 200W each. Would be a fun project and the drivers will be under $400!
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post #59 of 411 Old 07-28-2014, 02:14 PM
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Quote:
Originally Posted by Mfusick View Post
Ok take a look at this:








School me up on how I should be thinking. Couple specific things I'd like to know is:

What controls the tuning ? How do I adjust the low corner up and down?

What controls the height of the peaks and valleys ? How do I smooth things out ?

Is there some kind of "auto calculate" way I could find the optimal result for a specific driver at a specific tuning ?
First of all, go back to the design tutorial, but instead of 'CON', make the segments 'PAR'. I wrote the tutorial 5 years ago, and HornResp is a much nicer program now. PAR will more accurately model what you build (2 parallel sides, flaring in one dimension). Also, Make the Horn an 'OD' horn, by double-clicking 'Nd' until it reads 'OD'.

From the 'Input Prameters' page, go to the 'Loudspeaker Wizard'. You can then use sliders to control each variable.

Tuning (low corner) is a function of horn length and flare rate (how fast it gets bigger).

The peaks and valleys are controlled by controlling each parameter. It is a series of tradeoffs. To get one thing, you often have to give up another. Use the sliders and see what I mean. Start with the 'S1=S2=S3' throat like in the tutorial, and only play with L23 and L34 and S4. Make S1=S2=S3 slightly bigger than 1/3rd the Sd of the driver (this sets the compression ratio), make Vrc 100L, and play with L23, L34 and S4. You can see that by changing the length and flare rate (by changing the mouth area), you can change the tuning, and you adjust the ripple amount. making the throat longer and shorter changes the ripple amount.

Then, you can change the compression ratio. You will find that smaller compression ratios give you better looking responses, but it comes at a cost. More distortion, and when you build, you will not get what you modeled at higher SPL, too much 'friction' in the horn to put it plainly... I use a compression ratio less than 3 for 15" drivers, and less than 2.5 for 18" drivers. For 12" and smaller, you can increase the comp ratio to a certain extent. This is where trial and error rule supreme. I always err on the side of a larger comp ratio. That means a larger box. But to play low, you need enormous, VERY well braced boxes. If you can feel a panel vibrate on a horn, that is lost SPL out of the mouth.

You have lots of fooling around to do with hornresp. You will soon graduate to varying the size of S3 and adding another segment to further control the horn once you know what you are doing with the simple horn.

Although the hornresp-included tutorial/help is cumbersome, read it and look up the terms you do not understand.

I like OD horns because they are easy to design and fold, but they have to be much bigger or used in multiples for the same SPL at the same low corner as a TH, and highpassing for excursion control is optional if you will not flood them with power. I do not like THs as much because they are harder to fold, and expose one side of the driver to the 'air', increasing directly radiated distortion components that are lowpassed in the OD horn by the horn itself...and highpassing for excursion control is usually not optional. That said, THs are one of the most efficient ways to get mammoth SPL at a certain low corner in the least cuft without having to use multiples, and with little power. Because they have no rear chamber, you essentially use that space for more horn. There are also time domain issues, but these are all the tradeoffs inherent in designing a subwoofer.

Get some measured T/S specs and get to crackin' and moving those sliders around. You can do much better than the model you posted.

As you can already tell, you will find a model you like. It will change about eleventy billion times, then you will finally translate that model into sketchup and fold it, and build it, and measure it. You will learn lessons, and repeat the exercise until you find something that will work well and fits your needs, then build 8 of them and collapse your house.

JSS
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post #60 of 411 Old 07-28-2014, 02:28 PM - Thread Starter
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Quote:
Originally Posted by Bassment View Post
What's the reason you have a strict budget for drivers but unlimited funds for wood? Do you have access to free or super cheap wood or something?

At least if you spend most of your budget on drivers, and less on wood, they hold their value decently and have re-sale value. With large wood boxes, you won't get re-sale value out of those.

Looking forward to see this theater build, it seems like you have researched it an insane amount, so it should be amazing.

I addressed this a little earlier with a clarification. I'm not "unlimited" on wood budget but I am starting an entire home remodel project that includes tearing off our roof, extending the home back, adding a mud room and breezway and garage and a large dedicated theater above the garage. It's not a weekend project.

The bottom line is I could easily sneak 25 sheets of ply and 20 tubes of PL premium past my wife a lot easier than I could sneak a tractor trailer full of sealed subwoofers being delivered and charged on our credit card. I don't have an unlimited budget for everything - the total cost of the solution is always in the forefront of my considerations. I just feel like horns offer more bang for the buck and generally wood is cheap. I don't want to be wasteful though... I want to be efficient about it.


Quote:
Originally Posted by martinq View Post
Also curious about this. It's a basshorn dream come true (if true).
Sorta Wife doesn't realize the diverted materials as easily as subwoofers being delivered

I have up to $2000 in drivers available for budget. I have about $1000 in materials available (but I am flexible) and about $1000 in amps available (I have an inuke and XLS402 already also).

My goal is I want to make a serious bass solution that some WAF pussy can't beat if he just wrote a check for 10 grand and bought some high end gear. I want superior output and lower distortion, better dynamics, etc... ULF I don't care super much about it's mostly a fantasy. I'd like usable output at 10hz (think 100db, and certainly reference at 15hz but I won't chase that if it means muddy bass) Clean bass sounds funny, it's almost too good and distortion free. I want that.

-

"Too much is almost enough. Anything in life worth doing is worth overdoing. Moderation is for cowards."

Last edited by Mfusick; 07-28-2014 at 02:32 PM.
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