Blast from the past - my first and last DIY project - Quad 15" Sub Ottoman - AVS Forum
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post #1 of 27 Old 02-20-2012, 07:43 PM - Thread Starter
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This post has no reason for existance except that I'm having some fun reliving some memories tonight and thought I'd share. I've learned a lot at AVS and really enjoyed finding this forum and meeting some fellow enthusiasts. In a phrase - thanks guys for the many years of sharing your collective knowledge!

This post is in regards to my first major DIY project - I had no idea what I was doing, but I just wanted my house to sound as loud as my car audio system. I believe I made this thing in 2002 or 2003? - Definately during my college years! It was the typical build first - ask questions later project! Reading back through the advice threads I linked below from my 2005 threads made me laugh because now I know a bit more and understand what those guys were saying. Sadly this project made me abandon subwoofer DIY to this point- but luckily for me I found some subwoofers I finally absolutely love in the JTR Captivator Pro pair I currently sport! It seems like the DIY arena has expanded more over the years to better support amateurs and that's a great thing!

For this project - I bought four MA1550W subs new at auction for cheap, bought a bunch of 3/4" MDF, bought a full black cow hide off ebay (The hide was actually still shaped like a cow - which was odd to me - legs and everything. I remember putting it on over my shoulders and chasing my roomates around the house - ha). I bought a gad of screws and finish washers and went to town. The resulting subwoofer ottoman box was strong enough you could throw a dance party on top of it and it wouldn't creak. Each driver has its own seperate sealed chamber. I used a bottle of wood glue and tons of screws - the thing is solid enough to hit a car and win. I put a 5" fireproof foam layer on top of the ottoman so it was comfortable to sit on or lay on. At any rate - musically it was only soo soo - but it was a lot of fun because it 'kind of' gave you that feeling of car audio in your house! It was ---- at the time --- the coolest foot rest ever.

I took some pictures of it - at this point it's a bit rougher than it was when I made it ten years ago - but still SOLID and agressively fun to look at!



More pics at photobucket
http://s1191.photobucket.com/albums/...man%20Project/

Besides the sub depiction - you can really see how my theater room has progressed in that you tube video, compared to the current pics!!!


I remember posting asking for help on AVS to make it sound less --- boomy? or one note wonderish - - - and not even understanding the response and direction given.

At any rate I got this old subwoofer project out of the garage - dusted it off - because I was finally going to sell it today. The craigslist guy didn't show up so I'm playing with it tonight. I placed it in the same mid room, mid floor location it always sat when I used it.

This thing was never a smooth sounding sub, but it did get loud!
I remember when I first built it I lived in a split level home and it was in a small dining room (mid floor level). There happened to be a heavy glass pitcher of water on the dining room table - cranking the sub setup up with some music made that heavy glass pitcher full of water vibrate across the table. I thought that was incredible!!!

BUTTTTTTT -- I always wanted to make it better - was it the cabinet?
http://archive2.avsforum.com/avs-vb/...d.php?t=557252
or was it the subs or amp?
http://archive2.avsforum.com/avs-vb/...d.php?t=577872

turns out both - -

I took a FR graph of the ottoman sub setup using omnimic and it's no wonder I always thought it sounded like a one note wonder. I never applied any EQ when I used this thing. I had a Denon AVR 5700 at the time and it didn't have any Audyssey or external EQ ability and I didn't have any EQ - so what you see is what I heard for the several years I used it.

Here is the graph of the ottoman subwoofer - sealed with four 15" car audio drivers' naked response in my room. no smoothing, no EQ, just straight sub1 out through EP4000 - distance setting = 4 foot in AVR

vs.

My current JTR Captivator Pro subs naked response in my room. no smoothing, no AVR EQ - just straight sub1 and sub2 output to INuke 3000. distance settings are 13.5 foot in AVR.



The craigslist guy is missing out. The sub, despite its FR issues is still worth the couple hundred bucks asking price and I'm enjoying listening to it right now powered by the EP4000 and playing some pandora music - despite the peaky FR. If he doesn't pick it up soon then I might try to use the Inuke DSP and see how flat I can EQ the sound - just for kicks...

"Without subs it's just background music - with subs it's the main event!"
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post #2 of 27 Old 02-20-2012, 09:07 PM
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Don't want to spoil the party, but there has to be smoothing in those graphs.

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post #3 of 27 Old 02-20-2012, 09:07 PM
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This is.....hilarious.

Come back to your "sealed" roots.
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post #4 of 27 Old 02-20-2012, 09:50 PM - Thread Starter
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No smoothing. Just 10 captures averaged on each setup with omnimic.

"Without subs it's just background music - with subs it's the main event!"
Archaea's Theatre Room
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post #5 of 27 Old 02-20-2012, 09:51 PM
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Quote:
Originally Posted by Archaea View Post

No smoothing. Just 10 captures averaged on each setup with omnimic.

Well that's certainly a form of smoothing! All 10 measurements from identical mic locations?

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post #6 of 27 Old 02-20-2012, 10:13 PM
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Did you sim those drivers in that airspace? What did the Q end up being? Did you use any polyfill? I should probably read your threads for these answers lol

 

Originally Posted by Bill Fitzmaurice:
It's also the very sort of Voodoo Engineering that should never be done.

 

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post #7 of 27 Old 02-20-2012, 10:47 PM - Thread Starter
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Yes all from identical mic placement at mlp.

Nah I didn't sim anything. I built and hoped. ha.

A friend told me to add polyfill at one point so I did but I don't recall it making much difference positive or negative.

"Without subs it's just background music - with subs it's the main event!"
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post #8 of 27 Old 02-21-2012, 05:30 AM
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I smell the graph hounds on your tail.... I always just ask them how to run sweeps so i dont have to explain.....
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post #9 of 27 Old 02-21-2012, 07:01 AM
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That is funny. You should have called your theater the Ottoman Empire!

It might sell better on Craigslist if you hang a pair of Truck Nutz on it.
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post #10 of 27 Old 02-21-2012, 07:10 AM
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Quote:
Originally Posted by Bigus View Post

Don't want to spoil the party, but there has to be smoothing in those graphs.

Omnimic applies smoothing to their 'no smoothing' graphs in 2 ways; it uses limited data points and it squeezes the vertical and stretches the horizontal to a point that will make virtually any trace look good.

Same graph posted above scaled to a REW graph:



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post #11 of 27 Old 02-21-2012, 07:19 AM - Thread Starter
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Desertdome - I laughed in the elevator when I read your post.

bossobass - The omnimic x axis frequency 'range' for the graphs is user selectable. I can start at 5, 10, 15, 20hz - whatever I choose - and likewise top out at whatever I choose. The y axis spl spacing is user selectable too - 1db range between graph lines, 2db, 5db, 10db - etc. As far as limited data collection points I'm not up to date on that discussion - but I thought there was some contesting back and forth on that? I admit to not following that discussion and so I'm not sure where the final findings fell.

"Without subs it's just background music - with subs it's the main event!"
Archaea's Theatre Room
2011 KC Sub Shootout
2012 KC Blind Sub Shootout

My Subwoofer Recommendations by Pricepoint

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post #12 of 27 Old 02-21-2012, 09:40 AM
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Quote:
Originally Posted by Archaea View Post

Desertdome - I laughed in the elevator when I read your post.

bossobass - The omnimic x axis frequency 'range' for the graphs is user selectable. I can start at 5, 10, 15, 20hz - whatever I choose - and likewise top out at whatever I choose. The y axis spl spacing is user selectable too - 1db range between graph lines, 2db, 5db, 10db - etc. As far as limited data collection points I'm not up to date on that discussion - but I thought there was some contesting back and forth on that? I admit to not following that discussion and so I'm not sure where the final findings fell.

I'm aware of the OM options. Problem is, no one ever selects those options when they post a measurement result.

There was no contesting. There are limited data points and the OM guy admitted it. He just tried to obfuscate that fact by talking instead about FR resolution.

The trouble with the ottoman idea is limited placement away from boundaries. I assume the Caps FR was not measured with them in the same spot the ottoman was in?

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post #13 of 27 Old 02-21-2012, 09:46 AM
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Quote:
Originally Posted by bossobass View Post

The trouble with the ottoman idea is limited placement away from boundaries.

.. and the whole tripping over speaker wire thing.

 

My DIY Subs ... http://www.avsforum.com/avs-vb/showthread.php?t=1233892

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post #14 of 27 Old 02-21-2012, 10:59 AM - Thread Starter
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Quote:
Originally Posted by bossobass View Post

The trouble with the ottoman idea is limited placement away from boundaries. I assume the Caps FR was not measured with them in the same spot the ottoman was in?

Bosso

yea - you got it. The JTR Cap measurement was taken with no EQ from the positions on left and right of my screen as shown in the first post pics. They face out 90* from the seats. That is the best place I've found in my room for natural response and thus were the positions we used for our 2012 KC blind meet for all the dual sub contenders. When I face the caps forward in my room un-EQ'ed they get a strongly rising response towards 70hz and a 50hz null - both of which are mostly avoided by just turning the subs sideways in the exact same placement. The ottoman was measured, also with no EQ where it is shown in the pictures in the first post as well - immediately in front of the recliners.

Though my room doesn't really seem to offer room gain (http://www.avsforum.com/avs-vb/showt...1394073&page=2), placement surely does effect the graph in other ways and I agree that in most rooms you'd loose helpful boundary gains with a ottoman type sub in the middle of the room...HOWEVER -- you make up for that slightly in other ways.
IE My wife and I watched "Hitch" last night -- a romantic comedy without all the wiz bang explosions of the movies I favor. We both propped our feet up on the sub ottoman. Every single bass note we felt - - - because our feet are actually resting on the subwoofer. That was pretty enjoyable, even for a non eventful movie audition and I forgot that I missed that after not having it for several years with the subs I've used post this ottoman.

It's got me thinking I need to look into some subtle bass shakers to compliment the subwoofers tactile feel. I've discovered I don't like bass shakers in the few instances I've been around them, but perhaps because they are turned up too high and have seemed artificial. I do enjoy the subtle tactile vibration that occurs when in actual physical contact with non dual opposed subs.

"Without subs it's just background music - with subs it's the main event!"
Archaea's Theatre Room
2011 KC Sub Shootout
2012 KC Blind Sub Shootout

My Subwoofer Recommendations by Pricepoint

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post #15 of 27 Old 02-21-2012, 03:44 PM
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Quote:
Originally Posted by bossobass View Post

I'm aware of the OM options. Problem is, no one ever selects those options when they post a measurement result.

There was no contesting. There are limited data points and the OM guy admitted it. He just tried to obfuscate that fact by talking instead about FR resolution.

Bosso



Wow, nice example of the OmniMic graph

Care to link to the explanation of which you're referring? The explanation I read seemed acceptable.

Also, I've seen REW graphs as wacked out in every axis imaginable, how many/how often? An order of magnitude more often than the unreadable OM graphs of which you're referring. What's this mean, ....absolutely nothing.


Thanks

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(3)Seaton Cat12C up front, (4)QSC K8 sides/rears
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post #16 of 27 Old 02-21-2012, 03:57 PM
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I never see REW graphs with such a rectangular window, people always choose more of a square ratio, which is how most frequency responses are shown whether its manufacturer websites, audio magazines, illkas/riccis test, etc.

The ratio of the omnimac graph is always super wide, which is one of its problems.

Want to measure your subwoofers? check out my dummies guide for a step by step process to Room EQ wizard
http://polaraudio.blogspot.com/2012/01/calibration.html
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post #17 of 27 Old 02-21-2012, 06:14 PM
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Quote:
Originally Posted by Archaea View Post

y

IE My wife and I watched "Hitch" last night -- a romantic comedy without all the wiz bang explosions of the movies I favor. We both propped our feet up on the sub ottoman. Every single bass note we felt - - - because our feet are actually resting on the subwoofer. That was pretty enjoyable, even for a non eventful movie audition and I forgot that I missed that after not having it for several years with the subs I've used post this ottoman.

It's got me thinking I need to look into some subtle bass shakers to compliment the subwoofers tactile feel. I've discovered I don't like bass shakers in the few instances I've been around them, but perhaps because they are turned up too high and have seemed artificial. I do enjoy the subtle tactile vibration that occurs when in actual physical contact with non dual opposed subs.

Ha, I'd buy that from you but since I'm all about tactile feel I'd probably end up listening to music curled up in the fetal position on top of the ottoman.

I also have tried bass shakers and I didn't like them either, but I had the cheapies, the aura something or other. It didn't seem natural and felt like cheating.

I think I really miss having an elevated floor, that vibration ripping through the floor makes a huge difference I think.
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post #18 of 27 Old 02-21-2012, 06:38 PM - Thread Starter
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Ha carp. Thinking of you curled up on the ottoman with a chesire cat grin makes me laugh!

"Without subs it's just background music - with subs it's the main event!"
Archaea's Theatre Room
2011 KC Sub Shootout
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post #19 of 27 Old 02-21-2012, 06:58 PM
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Haha, you'd have to make another ottoman that I could put on top of me.

Ottoman sandwich sub. Sounds very practical.
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post #20 of 27 Old 02-21-2012, 08:20 PM
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Quote:
Originally Posted by bossobass View Post

Omnimic applies smoothing to their 'no smoothing' graphs in 2 ways; it uses limited data points...

I haven't used omnimic personally. This probably explains my observation. Thanks.

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post #21 of 27 Old 02-22-2012, 05:04 AM
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Just grab the trace as 1-12th or higher and it will have enough data points. As for the window size, people use different sizes just as they do in REW.

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post #22 of 27 Old 02-22-2012, 10:08 AM
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I'm familiar with Ottoman sub builds. Looks pretty cool.

I'd advertise on a college campus. That would be cool in a dorm room or frat house.

Builds: Maelstrom 21 Ottoman Build, Dual Opposed MFW's x 2, Statements, SEOS-12/TD12M x 5. 
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post #23 of 27 Old 02-23-2012, 12:13 AM
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I like the idea of the Ottoman sort of sub. I've got a small futon daybed mattress brand new and though about adding a pair of my 12" drivers into it for a late night sub. The futon would also ameliorate the floor bounce from the mains.
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post #24 of 27 Old 02-23-2012, 01:10 PM
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Quote:
Originally Posted by carp View Post

Ha, I'd buy that from you but since I'm all about tactile feel I'd probably end up listening to music curled up in the fetal position on top of the ottoman.

I also have tried bass shakers and I didn't like them either, but I had the cheapies, the aura something or other. It didn't seem natural and felt like cheating.

I think I really miss having an elevated floor, that vibration ripping through the floor makes a huge difference I think.

I agree concerning the Aura's. Then I played around with EQ'ing them an it's a completely different experience now. No in the process of rebuilding the chair mounts which has a positive effect.
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post #25 of 27 Old 02-25-2012, 04:45 PM - Thread Starter
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haha -

today I was supposed to have somebody from craiglist come buy this - he decided against it - even for $225 . Said he wanted ported. At any rate I was playing with it and my daughter got mad at me. Watch this video - her reaction cracks me up. She wanted me to turn it down so she could come back down and play...haha.

It sounds great for $225. If I was a young single or college man again I'd sure as heck rather have this over the typical $200 subwoofer fodder. Somebody surely will buy it from me on craigslist???!!!!



"Without subs it's just background music - with subs it's the main event!"
Archaea's Theatre Room
2011 KC Sub Shootout
2012 KC Blind Sub Shootout

My Subwoofer Recommendations by Pricepoint

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post #26 of 27 Old 02-26-2012, 05:49 PM - Thread Starter
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well it sold today for $200.

guy said I'll give you $200 for it. I said it's worth $225. he said I'll give you $200 for it. I said okay.

"Without subs it's just background music - with subs it's the main event!"
Archaea's Theatre Room
2011 KC Sub Shootout
2012 KC Blind Sub Shootout

My Subwoofer Recommendations by Pricepoint

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post #27 of 27 Old 02-26-2012, 06:09 PM
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That sounded really good!! Of course I was hearing it through my Caps, but still. My daughter's interest was perked when your little girl came on the screen, she's a cutie BTW.
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