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16 x 18's in a 1500ft^3 Space - Popalock's Sub Build - Page 10

post #271 of 943
Quote:
Originally Posted by popalock View Post

Just dropped coin on another FP14000 Clone.

Hoping it will be here before next weekend as I'm having a little get together of sorts.

Let me guess, the police tongue.gif

I just had to pop my ears as the pressure your system will generate is too intense even from all the way over here!
post #272 of 943
C
Mark

Just to make sure I got it right, do you expect 5 Hz signal to get less gain from constructive interference than 10hz signal would?
post #273 of 943
Quote:
Originally Posted by Mark Seaton View Post

Posing this question suggest that you haven't broken down the math on what is really happening. From your example, consider 5Hz sine wave with a simple front wall reflection from 18" making for a ~36" path difference to the listener which makes for less than a 5 degree phase difference. At 90 degrees phase difference you get to no additional gain (2 sources = output of 1) and that doesn't come into play until more than 56 FEET of path difference from the direct sound. That's a pretty complex reflection path in most rooms. You can imagine that in the same room, a 10Hz signal reaches this point around 28 feet path difference, and hence you would see less gain as fewer reflections will be constructive. Within that first 90 degrees of phase difference you have no way to discern separate sounds. They are all the same sine wave that add to different degrees.

Quote:
Originally Posted by zheka View Post

C
Mark

Just to make sure I got it right, do you expect 5 Hz signal to get less gain from constructive interference than 10hz signal would?

Re-read above. Opposite. As a simple conceptual example, more reflections in the same room fit in a 56' reflection window (5Hz) than in a 28' window (10Hz). More reflections within this window will result in more gain.
post #274 of 943
When I re-read the above I am understanding it to mean there's better summation at 5hz than at 10hz... ? I'm on a phone, maybe I'm missing something here.
post #275 of 943
Quote:
Originally Posted by Mark Seaton View Post


Re-read above. Opposite. As a simple conceptual example, more reflections in the same room fit in a 56' reflection window (5Hz) than in a 28' window (10Hz). More reflections within this window will result in more gain.
Got it. Thank you.
This must be what maxmercy meant by lower frequency waves "having more time for a constructive process to evolve"
Edited by zheka - 3/25/13 at 5:41pm
post #276 of 943
Quote:
Originally Posted by zheka View Post

Quote:
Originally Posted by Mark Seaton View Post


Re-read above. Opposite. As a simple conceptual example, more reflections in the same room fit in a 56' reflection window (5Hz) than in a 28' window (10Hz). More reflections within this window will result in more gain.
Got it. Thank you.
This must be what maxmercy meant by "having more time for a constructive process to evolve"

Correct. Same idea. Do read the linked post, as I clarified there more about how both can apply, and that a simple pressure vessel description is a simplification that aligns perfectly well with other analysis for the right conditions. Of course the important part is knowing when such simplifications break down.
post #277 of 943
Thread Starter 
Rear (nearfield) boxes ready for subs:

post #278 of 943
More interested in the bowling ping pong table you have! Any triangular shaped moisture marks near the back edge on that thing? eek.gifwink.gif
post #279 of 943
Quote:
Originally Posted by NathanJ View Post

I am curious if even JapanDave's bunker qualifies for a bunker. It seems to me that having a framed wall in front of the concrete would absorb some of the energy instead of staying rigid like just concrete.

Going off that way of thinking, I think you would have more problems with the sound waves passing through the drivers cones, would you not? However if the space behind the framed wall was open then I could see your point, but it is not and is solid 10" concrete.
post #280 of 943
Quote:
Originally Posted by popalock View Post

Only two Clones pushing a 4 ohm stereo load, so technically closer to 18kw. 28kw does sound way cooler though.

I kid I kid cool.gif Just what any outside person will think.....holy 28kw haha hell round it to 20 or 30 sounds better and they won't know the difference.

Geez man, sounds like your system has cost you some real money from having to replace everything you've broken. No idea how this is all going to playout in the end, but I'd really prefer to avoid causing damage if I can. In your case (reinforcing cabinets?!?!) it sounds like you went through some trial and error. I'm sure I'll go through the same over time.

Yeah my kitchen is part of the same room since the theater is in the living room. The walls for the cabinets were solid blocked for extra meat to hang them, and they have plenty of extra long screws. Threw a few extra extras into the wine rack cab cause that would be a sucky mess to clean up. Pictures all get the metal clip tab mounting and gasket tape around the back edges. You'll find out what "moves" in your place biggrin.gif

Stopping a fan... Thats crazy talk sir... I like it.biggrin.gif

Yeah I remember KW's fan vid; funny that's what I thought of first.

Anyone have quick access to one of KW's old videos of him murdering his fan with his IB setup... before he added ceiling bracing. That was a fun video and the only way I could imagine "stopping" a fan.
post #281 of 943
Quote:
Originally Posted by popalock View Post

Rear (nearfield) boxes ready for subs:


Almost there! smile.gif
post #282 of 943
Quote:
Originally Posted by popalock View Post

Rear (nearfield) boxes ready for subs:


What is the depth and cubic feet of that box? I am thinking about building some into my columns and saw where the mounting depth was 9.5" but wasn't sure how close you could get to that number.
post #283 of 943
Thread Starter 
Quote:
Originally Posted by beastaudio View Post

More interested in the bowling ping pong table you have! Any triangular shaped moisture marks near the back edge on that thing? eek.gifwink.gif

Haha, stain free. Not from the lack of beer-pon. More-so from me policing the spills! It's my daughters, so I gotta keep it clean for her and her friends because they are always playing (regular pong).
post #284 of 943
Thread Starter 
Quote:
Originally Posted by auburnu008 View Post

What is the depth and cubic feet of that box? I am thinking about building some into my columns and saw where the mounting depth was 9.5" but wasn't sure how close you could get to that number.

bdaniels posted this drawing here.
LL

I use the above drawing as a reference point. That said, my boxes currently are 11.75" deep. I made a mistake in the inital design (measure 15 times, cut once, still F* it up) by not accounting for the .75" thickness of the box rear panel. I compensated by adding a double thick front baffle to give me a bit more mounting room. With the sub having a mounting depth of 9.75", I now have a clearance of 1.25" from the back of the box. Optimally, I would have preferred at least 2", but I had to work within my space limitations. Very tight, but I'llI will be ok in the grand scheme of things. The box will net each sub 3.87ft^3 of internal volume.
post #285 of 943
Thread Starter 
Quote:
Originally Posted by mjaudio View Post

Let me guess, the police tongue.gif

I just had to pop my ears as the pressure your system will generate is too intense even from all the way over here!

Lol... You know, I've never walked outside to see if any sound transfers through my basement walls? I'll have to check that out in a few days when I get my new Clone in and have all subs up and running.

Let me know next time you are up in the DC area man! I'd love for some of the Cali crew stop by for a demo...

Quote:
Originally Posted by Mark Seaton View Post


Re-read above. Opposite. As a simple conceptual example, more reflections in the same room fit in a 56' reflection window (5Hz) than in a 28' window (10Hz). More reflections within this window will result in more gain.

I really want to jump into this conversation without showing my complete and utter igorance, but I doubt that is possible at this point in time. I'll ask a question regardless.

The depth of my current room is right about 14'. Anything above a 14' long wavelength (20Hz and below) is constructive? Or, at least, has a higher probability of being constructive? Is that an overly simplistic view? I'm taking baby steps guys...lol
post #286 of 943
I damn near did exactly what you have done with a quad, but I feared my ba!!s would no longer be attached as my pair of duals had to go into an existing living room. I'm fine though as I have plenty of output with the pair and duals to help even response.

If my eventual room needs more output though, I think I'm definitely going to consider dual quads, lol. The thing that drives me nuts though is DOUBLING the $ for a scant few dbs of output in re to (2) cabs vs (4).


James
Edited by mastermaybe - 3/26/13 at 8:50am
post #287 of 943
Quote:
Originally Posted by mastermaybe View Post

The thing that drives me nuts though is DOUBLING the $ for a scant few dbs of output in re to (2) cabs vs (4).


James

You know I felt that exact same way before going from dual LMS's to quads. I figured I could just turn up the duals 6db's and be in the same boat. MAN WAS I WRONG! Doubling the sub system made a HUGE difference. If I had sum it up in one word I'd say, EFFORTLESS.
post #288 of 943
Thread Starter 
Quote:
Originally Posted by mastermaybe View Post

I damn near did exactly what you have done with a quad, but I feared my ba!!s would no longer be attached as my pair of duals had to go into an existing living room. I'm fine though as I have plenty of output with the pair and duals to help even response.

If my eventual room needs more output though, I think I'm definitely going to consider dual quads, lol. The thing that drives me nuts though is DOUBLING the $ for a scant few dbs of output in re to (2) cabs vs (4).


James

I've seen your current space. Sure would look good with dual quads stacked to the ceiling. smile.gif

It only took you 72 hours to make the boxes you have now. Plan around the wifes next weekend or business trip and slap together two more... Better yet, "plan" a relaxing weekend get away for her and her girls (sisters/mom/friends/etc...). When you build your new boxes, just be sure to make some nice grills and your new boxes will blend right in with the rest of your AV gear and go unnoticed...lol

It's better to ask for forgiveness than permission, right?

Do it...

I can email you my sketchup files and cutsheets if you want...

Quote:
Originally Posted by edoggrc51 View Post

You know I felt that exact same way before going from dual LMS's to quads. I figured I could just turn up the duals 6db's and be in the same boat. MAN WAS I WRONG! Doubling the sub system made a HUGE difference. If I had sum it up in one word I'd say, EFFORTLESS.

You increased your output while, at the same time, lowering the THD the lowest distortion super-sub in the world...

I must say though. I've seen your space. Sure would look good wth dual quads stacked to the ceiling.biggrin.gif
post #289 of 943
Quote:
Originally Posted by edoggrc51 View Post

You know I felt that exact same way before going from dual LMS's to quads. I figured I could just turn up the duals 6db's and be in the same boat. MAN WAS I WRONG! Doubling the sub system made a HUGE difference. If I had sum it up in one word I'd say, EFFORTLESS.

I agree 100% with what you just said. It really was a "I can't believe it made that much of a difference" moment and I even stood up to see how much the drivers were actually moving. That was also the moment I thought "Damn, I wish I would have just kept my dual LMS Ultra's and added another pair" frown.gif
post #290 of 943
Quote:
Originally Posted by mjaudio View Post

I agree 100% with what you just said. It really was a "I can't believe it made that much of a difference" moment and I even stood up to see how much the drivers were actually moving. That was also the moment I thought "Damn, I wish I would have just kept my dual LMS Ultra's and added another pair" frown.gif

Yeah....

I kinda wish I had just started investing in them, myself. But! I have a ton of 18's so I guess that's kind of cool too. tongue.gif
post #291 of 943
Thread Starter 
Quote:
Originally Posted by mjaudio View Post

I agree 100% with what you just said. It really was a "I can't believe it made that much of a difference" moment and I even stood up to see how much the drivers were actually moving. That was also the moment I thought "Damn, I wish I would have just kept my dual LMS Ultra's and added another pair" frown.gif

Still crossing my fingers that won't be the case for me...

I'm going to avoid any quad or octo LMS-U setups I happen to come across in the future...
post #292 of 943
Thread Starter 
Quote:
Originally Posted by popalock View Post

Still crossing my fingers that won't be the case for me...

I'm going to avoid any quad or octo LMS-U setups I happen to come across in the future...

Check out what my daughter made for me today...





Yes, those are speakers growing out of my knees, hair, arm and shirt pocket. Don't know why she felt compelled to set my big speaker boxes on fire? Hope it's not a bad omen. I thought it was awesome though...
post #293 of 943
Ahahahahaha!

That is soooo cute. smile.gif

Happy Birthday!
post #294 of 943
Left is Right, Right is Wrong dude.... I am glad she at least knew that speakers exploding from your legs would cause a slight bit of bleeding. Looks like you are only going to be out one driver in one box and the whole other box in general. Let me know if I need to grab a few more SI18's before I head that way, assuming her predictions are correct...
post #295 of 943
I am laughing out loud at my desk right now. Love that picture. WTF goes through kids heads eh. Awesome!
post #296 of 943
Thread Starter 
Quote:
Originally Posted by Scott Simonian View Post

Ahahahahaha!

That is soooo cute. smile.gif

Happy Birthday!

Haha, thanks man.

I asked her what was up with the ear piercing and bags under my eyes and she just smiled... Good stuff.
post #297 of 943
That's the best card ever! I liked all the details and had me LOL.

Happy Birthday!
post #298 of 943
Quote:
Originally Posted by popalock View Post

Quote:
Originally Posted by Scott Simonian View Post

Ahahahahaha!

That is soooo cute. smile.gif

Happy Birthday!

Haha, thanks man.

I asked her what was up with the ear piercing and bags under my eyes and she just smiled... Good stuff.

She told you: "You are getting old" haha
post #299 of 943
Happy birthday, Pop. Love the card. Now that is a perfect example of constructive interference.
post #300 of 943
That card is definitely a keeper. Happy birthday Austin.
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