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Discussion Starter · #1 · (Edited)
DIY Dedicated Home Theater - 7.5(20).4 build

The Story:

I told my wife I was going to spend $10k on a home theater and she made fun of me for about two weeks. So I dragged her to Audio Advice and the Best Buy Magnolia center to let her experience some really high quality speakers and projector setups. She loved it but was still not ok with spending so much money. So the next week we went to the movies and the theater just happen to be the worst one I have ever been in. It was in the back of the building, it hadn't been updated in 15-20 yrs, all the seats squeaked when you moved, it smelled, you could constantly hear the theater next to it, and there were a lot of loud people. It was an overall horrible experience. As we were leaving I said $10k for a home theater doesn't look so bad now does it? That is when we agreed we could convert our bonus room into a home theater. I have spent the last 6 months researching things and have finally started buying things. I am going the DIY route with the speakers.

Goal:

Replace my 1080p 65" TV with damaged screen and soundbar with fully immersive home theater that I will never want to leave!

Current Plan:

4K Projector with 138" Diagonal Screen - 16:9 ratio - 7.5(20).4 Surround Sound - Going the DIY route

Usage:

-90% Home Theater / 10% Music - Almost all the content will be streamed from Netflix, Disney+, Hulu, Prime Video, or HBO Now.
-Normally 1-2 people viewing at a time but max would be 4 if friends come over.



Purchased:
Projector - Epson Home Cinema 5050UB
Screen - Seymour AV DIY XD 138"
Receiver - Denon AVR-X4500H
Streaming Platform - Nvidia Shield Pro 2019
LCR - 3x DIYSG 1099
Surround - 4x DIYSG HT-12
ATMOS - 4x DIYSG HT-8
Subwoofer - 20x JBL 12" GX1200
Sub Amp- Sinbosen Amplifier FP20000q
LR or H1/H2 AMP - Crown XTI1000


To-Do List:
-Remove excess stuff from room
-Replace ceiling fan with flush mount light
-Determine exact speaker placement
-Wire room
-Paint walls, ceiling, trim, doors, & A/C registers black
-Prepare Garage for speaker building
-Install projector
-Build/Setup Screen
-Build/Setup 3x 1099s
-Build/Setup 4x HT-12
-Build/Setup 4x HT-8
-Build/Setup 5x Subwoofer cabinets with 4x 12" JBLs in each
-Blackout Windows/Make Curtains
-Sound Proofing - 24x 2'x4'x4" Rockwool Soundproof Panels


Current Situation
-Ran out of speaker cable so just ordered 200' more
-Mounting 2 of the HT-12s today and tomorrow I will mount the other 2 when I find a bracket that will angle the rears in
-Eric is shipping me the HT-8s
-Electrician is coming to put in a 100 amp sub panel in the storage room off my HT. He will also be putting in the 220v 30a receptacle for my Sinbosen FP20000q amp and two 15 amp receptacles.

Current Situation/Questions about the subwoofers:
-With 4 of the 12" JBLs in each box wired to 4 ohms that puts them at 1250 watts RMS. The AMP I have for them does 4ohm Stereo Power (RMS): 4,000W X 4CH. Will this cause a problem with overpowering the speakers?


Room:
- Completely light controlled since the windows will be blacked out
-304 sq. ft. - 2443 Cubic ft.
-Already wired room with Ethernet
-Lowish attic above but still fully accessible
-The couch can be moved around some depending on speaker placement and screen size. I usually like a full view experience since it feels more immersive.
-I was thinking of mounting the projector at 14' from where the screen would be and sitting 10' from the screen.
-I do not have to worry about disturbing the neighbors.


Pictures:







Messy Room:




Messy Room:



Messy Room:




Side Speaker Placement - Boxes underneath are just to hold up test box






Side Speaker Placement - Boxes underneath are just to hold up test box



Atmos Speaker Placement:





Atmos Speaker Placement:


 

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You're off to a good start here, and that room will be absolutely rocking when you're done. I wanted to ask what you felt the Nvidia Shield would provide over and above the Roku Premiere. I had planned to go with a Shield for our basement theatre, but the Roku I have (Premiere? Plus? I can't remember) has been pretty flawless so far, and I may just stick with something similar when the time comes.
 

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Discussion Starter · #3 ·
@OJ Bartley I have the Roku Premiere currently and I will be upgrading to the Nvidia Shield simply due to the fact that I want to have a wired connection instead of a wireless connection. I also want the ability to stream/display my PC games to my projector which is on the other side of the house.

I am currently stuck on which AMPs and MiniDSP to buy.
 

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Discussion Starter · #4 ·
I have a question about power requirements. So am building 5 subwoofer boxes and each box will have four 12" subwoofers in it. They are 4 ohm and 250 watts RMS. I am going to wire 2 set in series and then those sets in parallel to keep the impedance at 4 ohm. I used a calculator to determine that if I sit 10 ft away, have a target SPL of 100 dB, with 90dB sensitivity and want 3 dB of headroom I will need 185 watts of power. I read that the amp I power it with should be rated for twice that required power to help eliminate clipping for the 4 ohm impedance that my speakers are wired.
Now my question is do I need an amp that will provide 370 watts of power (185 * 2) to the box or do I need an amp that will provide 185 required power * 2 * 4 speakers = 1480 watts?

https://www.jbl.com/on/demandware.s...701/pdfs/JBL_CX1200_Owners-Manual_English.pdf
 

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So, what kind of screen are you looking at and what kind of budget? I love my Stewart Cima Neve but previously had a Silver Ticket screen that was good when the budget was a bit tight.
 

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I have a question about power requirements. So am building 5 subwoofer boxes and each box will have four 12" subwoofers in it. They are 4 ohm and 250 watts RMS. I am going to wire 2 set in series and then those sets in parallel to keep the impedance at 4 ohm. I used a calculator to determine that if I sit 10 ft away, have a target SPL of 100 dB, with 90dB sensitivity and want 3 dB of headroom I will need 185 watts of power. I read that the amp I power it with should be rated for twice that required power to help eliminate clipping for the 4 ohm impedance that my speakers are wired.
Now my question is do I need an amp that will provide 370 watts of power (185 * 2) to the box or do I need an amp that will provide 185 required power * 2 * 4 speakers = 1480 watts?

https://www.jbl.com/on/demandware.s...701/pdfs/JBL_CX1200_Owners-Manual_English.pdf
I am powering 9 of the JBL's with an Inuke 3000D in a "magic square" setup I am copying from this thread..https://www.avsforum.com/forum/155-diy-speakers-subs/3059746-magic-square-subwoofer-array.html So far there is plenty of power but I am still getting them dialed in. Theoretically you could wire 16 of them to a 4 ohm load in a larger magic square and power them all from a 6000 and place a 4 woofer box in each corner but it would limit your ability to EQ each corner separately. You may get more input in the main JBL thread https://www.avsforum.com/forum/155-...4-12-jbl-speaker-29-black-friday-bestbuy.html
 
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