Frankenstein Atmos – It’s Alive!!


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600 Club - QQ All-Star
Since 2002/2003
Mar 11, 2002
This is going to be really long, so if you skip it, it won’t hurt my feelings.

As promised (threatened?) on another thread, here is my “Frankenstein Atmos" system I recently installed.

First – The Room: My living room is approximately square - 22’ x 22’. It is in the center of the house, so it doesn’t feel claustrophobic as it might if it was a side room. The front and back walls have open doorways nearly in the corners on both sides. The left wall is brick with an unused fireplace with closed doors and two large windows. The right wall is half open to another room and, along with the front and back walls, has wood paneling. The carpeting is of medium padding. No echoes but not dead either – just right for me. The room has a vaulted ceiling which luckily has the apex at the very center of the room, running from front to back.

I already had a 7.3 system with some “height” enhancement in the rear half of the room having installed two 8” coaxial speakers in the ceiling just behind the listening area (a large leather couch) for channels 6 & 7 (the “surround back” channels). The front and rears are floor standing ESS AMT1s (B&Ds)). All my audio/video gear is in an adjacent “control room” – only the speakers are in the listening room.

Atmos – Frankenstein-style: My receiver/amp has DTS-MA and DD, but not Atmos. So, until I decide to invest in an amp that does Atmos, here is what I have done: I installed another pair of 8” coaxial speakers in the ceiling, roughly between the front speakers and the listening position (as detailed in Atmos diagrams) and added another stereo amp – a Technics SA-AX7 – to power them. The vaulted ceiling angles all four ceiling speakers down to the room. This really helps to create a “phantom” channel between each pair, just like toeing-in a normal stereo pair set-up. I much prefer this to systems I have heard that have a “flat” ceiling that seem to pinpoint the output of the ceiling speakers straight down. The speakers are “raw”, meaning they are just the speakers – no surrounding plastic cage that you push up into the ceiling made to specifically be ceiling speakers – much cheaper, too. I used standard metal ceiling speaker grills, cut holes just large enough for the cones in the ceiling drywall and used screws, washers and nuts to secure the speakers in the attic. My attic has fiberglass insulation about 9” thick and I didn’t want any of that getting inside the backs of the speakers. So, I went to Dollar Tree and bought four deep 10” wide plastic bowls like you would store food in and placed them over the backs of the speakers and secured those to the drywall with duct tape. I then covered them up with insulation.

But where to get the signal for the front ceiling speakers?

Enter the mad scientist…I know many on this forum absolutely hate the center channel. I instead decide to embrace it and expand its capabilities. This was partly to solve a problem that has always bothered me about my system. The center speakers - a full size ESS AMT1 tweeter/midrange and, using a salvage ESS crossover, a Sony center speaker positioned behind the AMT, firing to each side and through the AMT - sit on a shelf beneath the TV in a nice stand. Even though the shelf is open on the front and both sides, I have always felt the center sounded a bit “boxy”.

1) I split the center channel pre-out of the main amp to (both channels) of one of the inputs of the Technics amp creating a sort of inverted triangle of sound when paired with the existing center channel speakers. This really pulls the sound of the center out and up and is especially effective at improving the ability to hear dialog when watching a movie when the dialog is centered. (Audioholics just posted a long video on YouTube that addresses the problem of understanding dialog in surround movies – and it is mainly because of center channel speakers – not your hearing.) It also gives a more realistic sense that the actors’ voices are coming from the screen rather than below it. Initially I feared this would hamper the left and right stereo balance of the front channels (especially when listening to music), but it actually seems to enhance the separation of what you perceive is coming from each of the speakers.

2) I ran pre-amp signals from the FL & FR of the main amp to a second input of the Technics amp. If I play something that has no center channel the front ceiling speakers can add a bit of height to the existing FL & FR audio. But that seemed too simplistic so …

3) I connected a Fosgate 3610 decoder to the Tape Monitor loop of the Technics. In addition to its decoder settings, the 3610 also has a Center Cut feature (basically cancels mono info in a stereo signal) so if there was a problem blending the fronts with the ceilings it would just add some height ambience.

4) Ls and Rs outputs of the Fosgate feed a third input of the Technics amp which eliminates even more of the “common to both channels” audio of the original FL & FR signals, highlighting individual instruments or sounds. So, at this point I have three different options as to what signal to send to the front ceiling speakers and the Fosgate has 4 different ways to process a stereo signal – center cut, normal, medium and wide.

But wait...there’s more…

5) In the Tape Monitor loop of the Fosgate 3610, I hooked up a Hughes AK-100 SRS unit. The Hughes has several different options – SRS, 3D Mono, and Reverb Trim. You can see how these settings can be useful on both the mono center signal or the stereo front or surround channels coming out of the Technics or filtered through the Fosgate.

But wait… there’s still more…

6) The Hughes also has a Tape Monitor loop and to that I hooked a stereo ART Pro-Verb that I used to have in my guitar rig. The Pro-Verb has about 100 different reverb and delay settings, of which about 20 are useful in the manner in which I am using it now. (I don’t expect to use any of the gated, echoes, phase, chorus, etc.) It has a wet/dry slider so I can adjust how much the effect is applied to the signal it is processing.

The Fosgate, Hughes and Pro-Verb all have bypass settings, so any of the three can be punched in or out of the signal chain or used in any combination.

I have been doing lots of listening tests and it is great fun. I’m finding that the setting I am using most often is the center channel input, Fosgate tape monitor ‘in’, Hughes SRS ‘on’ with tape monitor ‘in’ with the Pro-Verb set with a 40/60 wet/dry medium reverb. It sounds very close to the sound of dialog you get in a very large movie theater but it is subtle not gimmicky. If it is too much reverb I can adjust the wet/dry control. Keep in mind the original center speaker(s) is only getting the unprocessed ‘dry’ signal it always did – only the front ceiling speakers are getting the processing so all delay/decoding effects are only happening overhead. And I can adjust the volume of each stereo pair – fronts, rears, back overheads and front overheads with the main amp having master volume control over the total.

When playing a true 5.1 or 7.1 recording, I can hear that all 9 speakers (plus the subs) are reproducing different sounds and instruments. It is very immersive..and it kicks ass!

It’s not ‘real’’s BETTER! Mwaaa-Haahh-Haaah-Haahh!! (maniacal laugh)

Oh, and Thank You to my wonderful wife for letting me do all this to our living room. She thinks it sounds great, too.