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7 x RE Audio XXX 18" subs, Infinite Baffle Sub, Ultimate IB build - Page 11

post #301 of 530
12/8/12 at 5:32pm
Quote:
Originally Posted by mjaudio View Post

I am anxiously awaiting updates too!
You guys and your XXX IB's are making me jumpy. I wish I could do a IB, RE is just down the street from me just teasing me to buy some more XXX's.

Time to join the club!
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post #302 of 530
12/8/12 at 6:21pm
Thread Starter 
Absolutely!!!!
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post #303 of 530
12/8/12 at 6:25pm
Ummm. Dave, aren't you adding 4 LMS Ultras to the mix?
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post #304 of 530
12/8/12 at 8:58pm
Thread Starter 
Quote:
Originally Posted by keager View Post

Ummm. Dave, aren't you adding 4 LMS Ultras to the mix?

Yes, I was intending to add the 4 LMS to this system. The only reason why I would possibly need them is to smooth out the frequency response.
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post #305 of 530
12/9/12 at 11:43am
The LMS Ultra's would probably add a nice mid-bass kick as well.
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post #306 of 530
12/9/12 at 11:45am
Quote:
Originally Posted by keager View Post

Time to join the club!

I wish I could but the only space for a IB would be the master bedroom closet or the garage and I will probably rent or sell this place in about 9 months.

With IB's is it just a lot of low bass, how is the mid-bass?
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post #307 of 530
12/9/12 at 4:06pm
Thread Starter 
Quote:
Originally Posted by mjaudio View Post

The LMS Ultra's would probably add a nice mid-bass kick as well.
Forgive my ignorance, but if the SPL levels are there across the ULF band to mid LF band, would it not sound (feel ) the same regardless of what type of sub you were to use? Or does some subs ,even at the same SPL give more slam in a particular region?
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post #308 of 530
12/9/12 at 4:20pm
I believe the thing with the RE's is they are very inefficent in the midbass region. You would need tons of amp and possibly worry about cooking the coils? However, Ricci maxed out a K10 amp on a sealed XXX.
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post #309 of 530
12/9/12 at 4:23pm
Quote:
Originally Posted by mjaudio View Post

I wish I could but the only space for a IB would be the master bedroom closet or the garage and I will probably rent or sell this place in about 9 months.
With IB's is it just a lot of low bass, how is the mid-bass?

My midbass seems decent. I do however still need to add two more drivers and eq them. How bout yours dave? Where do you cross them over at?
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post #310 of 530
12/9/12 at 4:26pm
Thread Starter 
Quote:
Originally Posted by keager View Post

I believe the thing with the RE's is they are very inefficent in the midbass region. You would need tons of amp and possibly worry about cooking the coils? However, Ricci maxed out a K10 amp on a sealed XXX.

I see. I will probably be crossing my subs @ 60-65 hz. But I will have to wait for the in room FR to see if that will be ideal.
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post #311 of 530
12/9/12 at 6:48pm
The XXX's have a lot of moving mass which is great for low bass but struggles with mid-bass. In your IB with 4 maybe that alleviates the problem though?

I sure would like to experience an IB one day, I have to try and convince one of my friends to cut some holes in there walls biggrin.gif
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post #312 of 530
12/9/12 at 6:55pm
Thread Starter 
Quote:
Originally Posted by mjaudio View Post

The XXX's have a lot of moving mass which is great for low bass but struggles with mid-bass. In your IB with 4 maybe that alleviates the problem though?
I sure would like to experience an IB one day, I have to try and convince one of my friends to cut some holes in there walls biggrin.gif

LOL. That should go over well! OK, so it is purely a SPL related problem in that particular frequency band. That is good to know, Thanks.
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post #313 of 530
12/10/12 at 2:12am
Thread Starter 
OK, did rough Photoshop of what the drivers ay the back of the room would look like.
A quote from the cult that has been bothering me regarding IB sub placements at the room of the LP. Although FOH and others have said it to be OK, I just wanted to see what you guys thought about it, or maybe explain whay it may not be a problem when multiple positions are used.

Quote:
"Generally speaking we do not recommend placing the IB behind or immediately beside the listening position (too many potential phase related issues with the mains/smearing the stereo image)."

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post #314 of 530
12/10/12 at 2:39am
I say build it. If I get the opportunity to have a new canvas to work with I am doing an IB with the XXX. I saw these things in action when Josh Ricci had them at a GTG. Man these things can really swing.

Looks fabulous.
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post #315 of 530
12/10/12 at 2:41am
Plus it looks just like the side of one of my cabinets
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post #316 of 530
12/10/12 at 2:52am

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post #317 of 530
12/10/12 at 5:54am
With your air traffic control center/ eq device, I imagine blending them in wouldn't be a problem. It's boldly going into obsecene overkill, but that is your call. You could put one or two lms's there in boxes temporarily to test the resulting FR.
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post #318 of 530
12/10/12 at 5:58am
Would you be able to make that area as structurally sound as the front IBs?
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post #319 of 530
12/10/12 at 6:36am
Thread Starter 
Quote:
Originally Posted by robertcharles View Post

I say build it. If I get the opportunity to have a new canvas to work with I am doing an IB with the XXX. I saw these things in action when Josh Ricci had them at a GTG. Man these things can really swing.
Looks fabulous.
Gota love those cabs! I followed your thread back then and I have a lot of respect for what you did. Thanks.
Quote:
Originally Posted by keager View Post

With your air traffic control center/ eq device, I imagine blending them in wouldn't be a problem. It's boldly going into obsecene overkill, but that is your call. You could put one or two lms's there in boxes temporarily to test the resulting FR.
I already know what the FR is from that position. That was were I was originally going to put the IB when I started researching. Over kill, nah... I would still be one less than Ricci!
Quote:
Originally Posted by keager View Post

Would you be able to make that area as structurally sound as the front IBs?
Absolutely, probably more so. The wall where that door is a key structural wall for the whole house and it is 12" thick. All I would need to do is anchor a couple of H beams run wall to wall in between the subs horizontally, then anchor some 2" x 8"'s around the frame of the door (Take the door frame out of coarse) and I would have no chance of getting any wall flex what so ever.
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post #320 of 530
12/10/12 at 8:49am
You know my long term plan was to use mine IB too. When I was house shopping a HT room that would be suitable for IB was initially high on my list. Priorities change as you guys know and I wasn't able to make that happen at the end of the day, which sucks because I have never owned an IB and never heard one either.
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post #321 of 530
12/10/12 at 9:28am
The recommendation not to place an IB behind the LP is merely for situations whereby that would be the only subwoofer source.

With judicious adjustments of both time alignment relative to the fronts, and careful low pass settings establishing the upper range roll-off, an essentially seamless blending should be attainable.
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post #322 of 530
12/10/12 at 9:59am
Quote:
Originally Posted by Ricci View Post

You know my long term plan was to use mine IB too. When I was house shopping a HT room that would be suitable for IB was initially high on my list. Priorities change as you guys know and I wasn't able to make that happen at the end of the day, which sucks because I have never owned an IB and never heard one either.

Lucky for you Ricci, two right in your neighborhood...Oregon and Japan!
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post #323 of 530
12/10/12 at 2:33pm
Thread Starter 
Quote:
Originally Posted by Ricci View Post

You know my long term plan was to use mine IB too. When I was house shopping a HT room that would be suitable for IB was initially high on my list. Priorities change as you guys know and I wasn't able to make that happen at the end of the day, which sucks because I have never owned an IB and never heard one either.
I just can't wait for all the silicon to dry (Everything is sealed up) and get some measurements done. I am giving the really thick beads of silicon about 5 days to cure, it is pretty cold here right now. Then I will finally be able to hear what an IB sounds like.
Quote:
Originally Posted by FOH View Post

The recommendation not to place an IB behind the LP is merely for situations whereby that would be the only subwoofer source.
With judicious adjustments of both time alignment relative to the fronts, and careful low pass settings establishing the upper range roll-off, an essentially seamless blending should be attainable.
With the RS20i, I have the ability to adjust down 1/1000 of a ms. So I guess I am going to have to fins a way to measure the distance of the subs and speakers pretty soon. So smearing issues are mainly due to time alignment? And when you talk of the Low Pass settings, are you talking of the possibility that the front and rear IB would have different settings? Or more so, to make the Low Pass setting so as the subs will not be localized as others have stated?
Quote:
Originally Posted by keager View Post

Lucky for you Ricci, two right in your neighborhood...Oregon and Japan!

LOL, pretty big neighborhood there Keager!!! tongue.gif
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post #324 of 530
12/11/12 at 4:14am
Thread Starter 
OK, I am pretty sketchy on wiring, so if someone in the know could help me out it would be appreciated.

I am about 2 beers away from pulling the trigger on another set of 3 RE XXX 18" subs for a second IB in the rear of the room.

With the subs having dual 2 ohm coils, if I was to wire 3 of them together, what is the possible outcomes for resistance? This will determine what amp I will get to run them.
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post #325 of 530
12/11/12 at 4:31am
for three drivers, dual 2 each, the options are: 0.33, 1.33, 3, and 12 ohms.

drivers wired in parallel for 1 ohm each:
either series for 1+1+1=3 ohms
or parallel 1/1+1/1+1/1=3 1/3=0.33 ohms

drivers wired in series for 4 ohm each:
either series for 4+4+4=12 ohms
or parallel 1/4+1/4+1/4=0.75 1/0.75=1.33 ohms
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post #326 of 530
12/11/12 at 4:45am
Thread Starter 
Thnaks for the quick reply LTD02. So I should be able to get about 6,000w from a real Lab Gruppen FP14000 into 3 drivers @ 12 ohms bridged? That would give me about 2000 w per driver which should be more than enough.
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post #327 of 530
12/11/12 at 5:49am
yeah, that or a hair higher peak.

you can always run one pair on one channel and a single on the second channel.

wiring one pair (coils in series, drivers in parallel) to net 2 ohms gives 7000 watts into the pair or 3500 watts each.

putting the third driver on the second channel with wired for 4 ohms (coils in series) would give up to 4400 watts.

for a max total wattage of 2x3500+1x4400 = 7000+4400 = 11,400 watts. if the drivers can handle it all that way. :-)
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post #328 of 530
12/11/12 at 9:08am
Here is a little visual representation for you Dave that also shows how they would hook up:

Dual 4 ohm coils:





Dual 2 ohm:






Here is a handy calculator I use and were I got the above images: http://www.the12volt.com/caraudio/woofer_configurations.asp
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post #329 of 530
12/11/12 at 10:13am
If you've not yet purchased the rear amp, and buying one now just for the rear drives, .... then perhaps a four channel FP10000Q @ 2100w@4ohm per driver, with an extra unused channel would be in order.

Wouldn't that be a much more advisable avenue given that 3 LMS'@3ohm total, would be ~4.5kw per driver?

Also, the series approach @12ohm total ~2.3kw/per driver, however with the added caveat of three drivers (6 coils) all in series, just doesn't seem as good an idea as each driver on it's own amp channel as would be w/the FP10000Q.

Odd numbers of subs presents challenges otherwise not encountered.

I think if you had a ton of rear wall bass trapping, you could get by without the rear subs. (Actually, 99.9% of people would be fine with one RE XXX 18" up front, it's easy to lose perspective)

To hell with perspective, ... with the the rears, you do have a better chance of a smoother FR, over a larger area.

"So smearing issues are mainly due to time alignment?"
Alignment in time with mains, front subs, and yes, careful adjustment of upper range of use. In other words, the low pass settings of the rears, ...when they begin rolling off the highs, ie., 45-55-60hz, etc. Typically, you want them active within the range required to help lessen modal issues, but not too high to and draw attention to themselves and be localizable. You'll see, this shouldn't be an issue.


Good luck
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post #330 of 530
12/11/12 at 2:27pm
Thread Starter 
Thanks LTD!

@MJ, that is a great web site, thanks for the link.

How would you wire up this pattern? Could you put the 2 + and 2 - together at terminal?


Quote:
Originally Posted by FOH View Post

If you've not yet purchased the rear amp, and buying one now just for the rear drives, .... then perhaps a four channel FP10000Q @ 2100w@4ohm per driver, with an extra unused channel would be in order.
Wouldn't that be a much more advisable avenue given that 3 LMS'@3ohm total, would be ~4.5kw per driver?
Also, the series approach @12ohm total ~2.3kw/per driver, however with the added caveat of three drivers (6 coils) all in series, just doesn't seem as good an idea as each driver on it's own amp channel as would be w/the FP10000Q.
Odd numbers of subs presents challenges otherwise not encountered.
I think if you had a ton of rear wall bass trapping, you could get by without the rear subs. (Actually, 99.9% of people would be fine with one RE XXX 18" up front, it's easy to lose perspective)
To hell with perspective, ... with the the rears, you do have a better chance of a smoother FR, over a larger area.
"So smearing issues are mainly due to time alignment?"
Alignment in time with mains, front subs, and yes, careful adjustment of upper range of use. In other words, the low pass settings of the rears, ...when they begin rolling off the highs, ie., 45-55-60hz, etc. Typically, you want them active within the range required to help lessen modal issues, but not too high to and draw attention to themselves and be localizable. You'll see, this shouldn't be an issue.
Good luck

I am just concerned with this RS20i's base management. I only have 4 channels to use for subs with this. However if I was to ignor that and just use a channel each for each sub I would deffinitely be better off with the FP 10000Q for sure. I am going to have to make a few measurements to see what the FR is like I guess.
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