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Keager's Quad RE XXX 18 Underfloor IB Build - Page 10

post #271 of 341
Quote:
Originally Posted by keager View Post

Pardon my ignorance, but does your diagram account for one driver needing to be reverse polarity? Thanks for your help.
One driver should not have reverse polarity unless you're making a dipole/bipole. Both are correct for a conventional subwoofer.
post #272 of 341
He has one driver mounted standard for his baffle and the other reversed and installed inset of the baffle so the drivers are kind of like this in his box <( <( instead of a normal D-O baffle that would be like this: )> <( or <( )> Does that make sense at all?
post #273 of 341
Thread Starter 
So I'm thinkin I would just do it like stereodude showed, but reverse all the connections on the second driver?
post #274 of 341
Quote:
Originally Posted by keager View Post

So I'm thinkin I would just do it like stereodude showed, but reverse all the connections on the second driver?
Maybe depending on how you mean it. Like this:



If you have more than one of these manifolds you need to be consistent between them and wire them all the same (in term of making sure the driver that gets wired backward is the one whose motor you can see or not).
post #275 of 341
Thread Starter 
Youmean not having two reversed drivers on the same channel? I'm not questioning your advice, just want to be sure I understand and dont blow up my amp.
post #276 of 341
Thread Starter 
BTW, construction of second manifold is done.
cool.gif
post #277 of 341
Quote:
Originally Posted by keager View Post

Youmean not having two reversed drivers on the same channel? I'm not questioning your advice, just want to be sure I understand and dont blow up my amp.
You won't blow up your amp. If you don't wire the two manifolds the same you would effectively end up with your two manifolds wired out of phase which would mean that when two drivers in one are pushing the other two drivers in the other are pulling and vice versa. That's what you want to avoid.
post #278 of 341
The pics of this install is like porn for an audiophile. smile.gif
post #279 of 341
Thread Starter 
Quote:
Originally Posted by TenTonBass View Post

The pics of this install is like porn for an audiophile. smile.gif
glad your following along! Something that is this challenging to put together is also very rewarding.
post #280 of 341
Thread Starter 
Quote:
Originally Posted by Stereodude View Post

You won't blow up your amp. If you don't wire the two manifolds the same you would effectively end up with your two manifolds wired out of phase which would mean that when two drivers in one are pushing the other two drivers in the other are pulling and vice versa. That's what you want to avoid.

Thanks alot, thats makes sense now.
post #281 of 341
Hey Keager,

With your infinite baffle is there a lot of noise outside your house? I always wondered that about infinite baffles that are located in the attic or sub area.
post #282 of 341
Quote:
Originally Posted by mjaudio View Post

Hey Keager,
With your infinite baffle is there a lot of noise outside your house? I always wondered that about infinite baffles that are located in the attic or sub area.
Oh oh!! I can see the wheels starting to spin Mike. biggrin.gif
post #283 of 341
Thread Starter 
So far, no. Havent really maxed it out yet due to stuff falling off walls, etc. Havent had any complaints anyway...we shall see after I add the second manifold
post #284 of 341
Quote:
Originally Posted by edoggrc51 View Post

Oh oh!! I can see the wheels starting to spin Mike. biggrin.gif

I am infinitely baffled at what your suggesting biggrin.gif
post #285 of 341
Quote:
Originally Posted by keager View Post

So far, no. Havent really maxed it out yet due to stuff falling off walls, etc. Havent had any complaints anyway...we shall see after I add the second manifold

Wow, haven't even maxed it out yet and already adding a second manifold, I like the way you think!
post #286 of 341
Thread Starter 
Quote:
Originally Posted by mjaudio View Post

Wow, haven't even maxed it out yet and already adding a second manifold, I like the way you think!
The most impressive part of the infinite baffle setup is the sound quality. Im really happy with it and I havent even implimented the mini dsp yet.
post #287 of 341
Quote:
Originally Posted by edoggrc51 View Post

Oh oh!! I can see the wheels starting to spin Mike. biggrin.gif

Haha, I thought the same thing when I read his question. It wasn't "just" a question...lol

Quote:
Originally Posted by mjaudio View Post

I am infinitely baffled at what your suggesting biggrin.gif

C'mon Mike! I'd bet that the attic is the only place left that you can make room to stuff subs 22-30...lol

Quote:
Originally Posted by keager View Post

The most impressive part of the infinite baffle setup is the sound quality. Im really happy with it and I havent even implimented the mini dsp yet.

That's awesome you are getting such a good result without the DSP! I have to imagine that it will only get better.
post #288 of 341
Thread Starter 
I literally had trouble sleeping last night trying to decide if I am going to swap the mismatched driver in my existing manifold. I know the significance is minimal, but it just drives me crazy knowing that they have a slightly different specs. hmm. Oh, I know how to justify it! Cuz if I'm going to run them bridged now, no decent god-fearing, crawspace slithering, black widow hunting bass head would run two drivers off the same channel! My back hurts already....lol
post #289 of 341
Quote:
Originally Posted by mjaudio View Post

Hey Keager,
With your infinite baffle is there a lot of noise outside your house? I always wondered that about infinite baffles that are located in the attic or sub area.

I was quite concerned about this prior to my quad 18 attic IB system. Above all else, I wanted to maintain a neighborly decorum, and certainly didn't want the sound contaminating the area around our home. Our neighbors aren't on top of us, but the home closest tothe IB end of the house is about 60-70 feet away.

Sound outside the structure isn't typically a problem.

I've really examined this at my place, and there's several components that seem interact and determine the result.
De-correlation, ... the LF/ULF outside is significantly lacking in the correlating energy in the power region and thru the midband. This seems to be crucial for the audible cues that construct the remaining spectral energy of the playback, and without it, and only hearing the LF there's very little recognizable sound. It's simply not something that fits our normal range of sounds we encounter.

Secondly, but not necessarily secondarily important, is the diplolar nature of the subwoofer energy outside the home.
Imagine for a moment, you build a stand alone listening room out-building. You build a state of the art IB. It's a killer, mammoth IB array, flush mounted in the front wall in the modestly sized room. The rear room, that the IB baskets are located in, shares a common outside wall with the listening room. Well, when the IB is operating full tilt, both the primary room, and the rear wave room have equal amounts of the energy, except it's opposite in polarity. While standing outside in the yard, being exposed to both sides of that wall, the energy nulls to a large degree. It doesn't cancel entirely due to any structural deviation strengthening or damping one panel moreso than the other, however it is quite effective at nulling a considerable amount of energy.

I've noticed more than anything, that resonances play the largest role in energy reaching my closest neighbor. At first I had a small vibrating gable end that needed additional security. Then I found the next item, etc, etc. I stopped after I addressed four items, it's relatively well damped outside. what you hear is huge transient induced movements of the entire structure, but you don't hear much defined tonality. The biggest LF eggres I have noticed, is via a 10 foot wide, triple-pane sliding glass door off my listening room to the back yard eek.gif , yeah I know.

The cool thing about the attic IB is you can throw enormous amounts of damping/absorption at it (attic insulation), and the inherent shape of the sloped roof reflects many of those wavelengths down into the dense fiberglass/cellulose absorption material. I've added a lot of extra absorption up there, the decay time up there is tight, for sure. I'd planned on a pressure based diaphramatic absorber experiment up there (tuned plywood right near a rigid 703 panel), but I'm nursing some serious health issues that often side line me and limit my exertion.

All in time. It's low on the list, ...actually it's not even on the list but I've thought about it


IB noise outside?
Not typically a problem.

Good fences, makes for good neighbors.
Well, dipole bass, from an IB, makes for good neighbors too.

Thanks
post #290 of 341
Hope you feel better FOH. Getthat health in check man.
post #291 of 341
Quote:
Originally Posted by popalock View Post

Hope you feel better FOH. Getthat health in check man.

Thanks, ... it is what it is, the new normal.

I'm good.
post #292 of 341
Thanks for the detailed explanation FOH.

I hope your health issues get better real soon.
post #293 of 341
Thread Starter 
OCD sufferers rejoice! I crawled into my crawlspace with a RE xxx 18 to replace the mismatched one in my existing manifold(after Ricci discovered that there were two different voicecoils). It was naturally a task filled with danger and aches and pains. But I have got it mounted at least. This time I didn't remove the manifold from the floor joists. I just had to get creative with prybars and floor jacks to get the driver to line up with the mounting holes, but alasI have succeeded! However I did lose a mounting screw in the process, so I'm going back for round two. After I finally got the first two screws started, it was straight out of a movie..A giant black widow lowers herself down to about 6 inches from my head! Being in a very awkward, and vulnerable position on my back, holding up the motor of an 80lb subwoofer, I had to think quick. I grabbed one of my 2x4 prybars and swatted her against the foundation and on the third attempt, squished her. My skin is still crawling. Well, going back underneath to rewire the subs to try my amp bridged! I need serious help....
post #294 of 341
Yep, ..... certifiable.
post #295 of 341
Quote:
Originally Posted by keager View Post

OCD sufferers rejoice! I crawled into my crawlspace with a RE xxx 18 to replace the mismatched one in my existing manifold(after Ricci discovered that there were two different voicecoils). It was naturally a task filled with danger and aches and pains. But I have got it mounted at least. This time I didn't remove the manifold from the floor joists. I just had to get creative with prybars and floor jacks to get the driver to line up with the mounting holes, but alasI have succeeded! However I did lose a mounting screw in the process, so I'm going back for round two. After I finally got the first two screws started, it was straight out of a movie..A giant black widow lowers herself down to about 6 inches from my head! Being in a very awkward, and vulnerable position on my back, holding up the motor of an 80lb subwoofer, I had to think quick. I grabbed one of my 2x4 prybars and swatted her against the foundation and on the third attempt, squished her. My skin is still crawling. Well, going back underneath to rewire the subs to try my amp bridged! I need serious help....

Nice work on getting the monster mounted and killing the spider...death to all black widows! Reminds me of years ago when my 3-y/o boy came walking up to my wife carrying a 12" long or so aspen branch with this "cool black spider" crawling on it. She would have let out a nice 'eek' anyway as she hates spiders, but once she noticed the red hourglass on it she screamed "OMG, black widow!" in bloody murder as it was crawling down towards his hand. I was about 20' away but got there quick and knocked it off the stick and turned it into a greasy spot on the concrete. smile.gif
post #296 of 341
Quote:
Originally Posted by keager View Post

OCD sufferers rejoice! I crawled into my crawlspace with a RE xxx 18 to replace the mismatched one in my existing manifold(after Ricci discovered that there were two different voicecoils). It was naturally a task filled with danger and aches and pains. But I have got it mounted at least. This time I didn't remove the manifold from the floor joists. I just had to get creative with prybars and floor jacks to get the driver to line up with the mounting holes, but alasI have succeeded! However I did lose a mounting screw in the process, so I'm going back for round two. After I finally got the first two screws started, it was straight out of a movie..A giant black widow lowers herself down to about 6 inches from my head! Being in a very awkward, and vulnerable position on my back, holding up the motor of an 80lb subwoofer, I had to think quick. I grabbed one of my 2x4 prybars and swatted her against the foundation and on the third attempt, squished her. My skin is still crawling. Well, going back underneath to rewire the subs to try my amp bridged! I need serious help....
LOL!!!! biggrin.gif

You sound like me. But I just noticed my drivers are mounted upside down. But bugger me if I am re- mounting them! LOL

Good work with the spider.
post #297 of 341
Thread Starter 
Yeah, I wouldn't worry about the logo if I were you. I've got a rattle now that the new driver is installed in the existing manifold. Sounds like maybe one of the wires under the house might be vibrating.. Maybe something rubbing on the new driver perhaps... I will crawl back under there tomorrow. Too much spiders and insulation for one day.
post #298 of 341
Thread Starter 
Well I think I found my rattle. I went outside and the foundation vent lids are rattling like crazy as the air tries to escape.lol. I know it could be placebo, but it sounds better now that I replaced that driver. Could the one driver with different specs have been adversly affecting the other driver? I know its unlikely, but I will sleep easier knowing they are the same now....
post #299 of 341
Thread Starter 
Quote:
Originally Posted by Stereodude View Post

Maybe depending on how you mean it. Like this:

If you have more than one of these manifolds you need to be consistent between them and wire them all the same (in term of making sure the driver that gets wired backward is the one whose motor you can see or not).

I tried wiring up the speakers to run bridged and I got very little output and the indicators on the amp showed that it was putting out quite a bit of power. I will try again tomorrow and take photos of how I have it connected.
post #300 of 341
Quote:
Originally Posted by keager View Post

I tried wiring up the speakers to run bridged and I got very little output and the indicators on the amp showed that it was putting out quite a bit of power. I will try again tomorrow and take photos of how I have it connected.
It sounds like you had the voice coils wired out of phase so they were producing magnetic fields that were direct opposites of each other.

Edit: Do you have a multimeter?

Note that the terminals to a single voice coil are circled in blue.



Also, could you see the drivers moving?
Edited by Stereodude - 12/7/12 at 4:51pm
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