Dedicated 7.4.6 Screening Room

diverdog

Standard Member
I'm really excited about building my first dedicated home theater. I enjoy watching TV sports, musicals and dramas, movies and listing to music. I'm not a gamer. Actually a better description might be a screening room as I have no interest in movie posters, popcorn machines or any décor that will distract from the viewing and listening experience. I spent many years in the professional AV arena so I've got a lot of knowledge and experience and I'll be doing all of the design/build myself.

The room is 19.5' W x 17' D x 10' H. No windows and one door at the back of each side wall. The screen wall will have wings as shown on the drawing. Screen will be a Seymour 120" diag. 16:9 AT with manual masking for scope. Viewing distance will be a single row at about 10'. Projector is still undecided but I'm leaning towards an LG HU810PW

Audio will be 7.4.6 with wiring available for front wide speakers as well. All speakers will be in wall to minimize SBIR. I'm a very pragmatic engineer and I like to choose products that have great performance but also great value. I was very impressed with the specs and reviews of the Monolith Ultra THX in-walls. Particularly the listening window frequency response. Center will be behind the screen and L&R will be on the wings for 60 degrees separation and aimed at the money seats. I purchased 7 from the Monoprice Ebay store for $287 ea. An astounding value! Atmos will be ELAC in ceiling with the 30 degree tilted drivers. Subs will be arrayed as front and rear center and side wall center and managed with a miniDSP. Front sub will be mounted on the floor flush with the screen wall. Since I have a maximum depth of 18" to work with I'm limited on sub selection. I've built many custom boxes but I have a ton of other construction to do I'd rather not build. I'm pretty sure I'm going to use Hsu UL 15's. Two in the front center as it is 2x further to the listening position and one each for back and side positions. I'm not a bass addict but I want clean powerful and evenly distributed bass in the listing position.
Processor and power amps are undecided but I think I'm going to go with the new Marantz SR8015 13 channel receiver.

I'm just starting to rip out the existing drywall. I'm installing a power subpanel and will be running 20 amp circuits for each sub and to the equipment rack located in an adjacent garage. I'm installing ASC IsoDamp multi layer walls. Not so much for sound isolation as for damping of wall ringing and softening bass resonances.

With great speakers I'm a believer in less is more for acoustical treatment. I know I'll need some absorption in the room to control RT60 and I'll start with behind the AT screen and rear wall. Then I'll experiment with first reflection points on the side walls and ceiling. I'm not a big fan of diffusers in home theater but I may experiment with it.
Really excited to finally getting started on this project!

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SparkerB

Active Member
Thanks for sharing your plans. My HT continues to be a great investment for me and my family. I hope you get as much enjoyment out of yours. I like your pragmatic approach.

Do you plan to use a local media streamer? I built a plex server for mine.

I found having a mix of sub sizes helps greatly with. Getting the balance between low and high attack mid bass. I have a 1500w velodyne for LFE and a 200w MJ acoustic which is dealing with mid bass duties. Its connected to the LCR rca outputs using a summing cable not via LFE. Prior to the MJ I had a 2000w 12 inch sunfire, it was unruly and threw the bass pass my seating position. Point of my ramblings is, consider introducing one sub at a time so you can figure out what power and size sub you need.

Also its worth investing in a good usb mic and rew (room eq wizard).

Look forward to seeing your build progress.
 

diverdog

Standard Member
SparkerB, thanks for your input and encouragement. I will have a media streamer but I haven't done my homework on which one yet. I have plenty of space in my rack and have CAT6 wiring pulled. How do you like Plex? Any issues to look out for?

REW is a fantastic tool and I do use it. I've been measuring and EQing systems for 40 years and the tools available today are amazing! With multiple subs I use a miniDSPhd to align and EQ the sub system and then have the AV processor treat the multiple sub system as one sound source for matching to the the other speakers. It's very interesting to see how the measurements smooth out at the listening position as each sub is integrated into the array. The layout of my screen wing walls and doors limits my placement choices for the subs to front and rear center and side wall centers.

It's certainly possible to use different sizes and types of subs to tailor the sound to your preference. I find that I can get excellent predictable results in deep bass and mid bass without doing so. Floyd Toole's research showed the way to manage modal bass nulls and resonances in small rooms with arrangements of multiple subs covering the same frequency band. Of course selecting subs with a flat frequency response beyond the crossover point is necessary. Since my bed layer of speakers conform to the Ultra THX specs they start rolling off at 80 hz so xover needs to be 70-90 hz for good integration. The ULS15 subs have ruler flat response and low distortion with plenty of mid bass output.
 

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SparkerB

Active Member
Its great to see you know what you're doing. That Purple EQ line is proper. I'm assuming the sound is on point. Subtle when required. Easy on the ears. Aggressive, almost frightening when required. ???

You are obviously a technical person so Plex may be a nice solution and judging by your value for money ethos, you may find some of the off the shelf solutions harder to justify. Plex is by no means perfect and with each update it seems to take one step forward and one step back. Having said that if you, as you say, do the research you can build a decent solution. One annoying thing is it can be temperamental if the Internet goes down, which defeats its purpose.

Off to bed, talk soon
 

diverdog

Standard Member
Its great to see you know what you're doing. That Purple EQ line is proper. I'm assuming the sound is on point. Subtle when required. Easy on the ears. Aggressive, almost frightening when required. ???

You are obviously a technical person so Plex may be a nice solution and judging by your value for money ethos, you may find some of the off the shelf solutions harder to justify. Plex is by no means perfect and with each update it seems to take one step forward and one step back. Having said that if you, as you say, do the research you can build a decent solution. One annoying thing is it can be temperamental if the Internet goes down, which defeats its purpose.

Off to bed, talk soon
I don't mind putting a computer together and playing a bit with software if the solution is very cost effective It's usually fun unless the software is buggy.

The HSU UL 15 is a sealed 15" that is a great value. About $800 US. Low harmonic distortion and group delay, solid deep base and smooth punchy mid bass. They sound awesome on both music and movies. The curves are from outdoor measurements with the internal EQ applied. They do not account for room gain. I'll bypass the internal EQ and use the miniDSP to tune them flat to 16hz and then apply a 48db/octave high pass [email protected] to protect the drivers
 

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