I am about to cut holes in my ceiling to install the Atmos speakers in my 5.1.2 setup.
Just before I do, I wanted to sanity check a couple of things. There are two viable options based on good speaker positioning recommended by Dolby (I am using the diagrams below as guidance).
Option 1. Speakers in the middle of the room, in line with the light fitting for aesthetics, the couch will be pulled forward so rear speakers can go behind the listening position and still get the >65° angle between the atmos speakers and listening position, however this means placing them directly under a beam and between the ceiling joists. The speakers will just squeeze into the gap but there is also a bundle of mains electrical cable that will be right on top of the speaker back-box.
Option 2. Speakers offset from the centre towards the listening position. This would make the install easier and put the speakers directly overhead a bit more (better?) but I have had to run the cables further than anticipated meaning would only just reach and perhaps look odd.
Both options are viable but if I go with option 1 is it fine to have the mains cables about an inch away from the speaker, even if the speaker cable crosses the cable bundle at 90° or would I need to raise the cable bundle away from the speaker?
Thanks. In the case of option 1 the bundle of mains cable would be within an inch of the back-box of the speaker (red circle is roughly where the speaker would be), I am guessing I would need to raise the cable bundle away from it on a block of wood.
Option 2. the speaker is a few inches away from the mains cable bundle and the speaker cable just crosses it at right angles.
I did run cable in rigid conduit where it runs in walls and plastered over but had a nightmare at the weekend trying to run cables in flexible trunking down the disused chimney. At one point the speaker cable got struck inside the trunking, I’m not even sure how it’s possible but nothing would free it, I pulled it so hard at one point the outer insulation sheath on the audio cable was breaking so I had to cut it free of the trunking. I thought it would be easy to drill a big hole in the chimney and drop cables down but I could not get the wire around the damper and smoke shelf etc. had to run the wire up and into the disused chimney where it has been de-constructed just below the roof and feed the cables down the old chimney lining in the end (hence my cables are now several feet shorter on account of having to go the extra distance).
That is one thing I’m really hoping not to screw up!
Might not be clear but the second photo is the space between the joists with the insulation lifted showing where a speaker will be installed. Unless I’ve really screwed up my measurements of the pitch of joists/spacing! Not visible in the photo is the gable-end wall, I have used that and the light fitting as ‘datums’. Stud finder kept going haywire, I think because of all the mains cables that run over ceiling or there are just screws everywhere in the plasterboard I’m not sure but it was really sensitive for some reason and alarmed near the whole ceiling.
In any case - I will be drilling tiny hole first and locating that before taking a jab saw to the ceiling!
Pulling cables through on a snake can be hard work. I remember too well. It takes a lot a patience and technique, especially when the trunking does awkward C or S shaped bends. I’ve even broken the speaker cable before trying to pull it through, and once even the snake (tip, solid teflon snakes aren’t good).
Even with your least desirable option you’ll probably be okay.
Not meaning to throw a spanner in the works but, would the locations for 4 Atmos speakers be easier than the location used with just 2? With 4, one set will be well forward of the seating position and one set well back.
Yep, it was the S bend that did it, cable got completely stuck. What surprised me is I couldn’t free it, even I pulled the whole lot out and flexed the conduit it was like the cable attached itself to the inside of the conduit somehow.
2 speakers because there are 2 powered height channels on my AVR (4 channels would mean using an additional power amp), it’s also a small room, it would be another £500 for matching second pair of atmos speakers + power amp cost so just installing 2.
I could move the light fitting but it isn’t really an issue where it is in the middle of ceiling, and the ceiling is newly plastered/painted so I kind of want to avoid creating holes that then require patching up. Just for clarification it is the entire bundle of mains cables that come up from the consumer unit below that are attached to the beam directly above where the speaker would go in option 1 - that is what I was wondering might cause interference.
There is special conduit grease you can buy specially for this. You need two people though. One to work the snake, and the other with rubber gloves on holding the greased rag and making sure the cable feeds through it before entering the conduit.
Though to be honest, a dedicated in-wall cable is different from regular speaker cable. It’s usually made of teflon or similar to prevent bonding to the PVC in the conduit.
I think I’m using the right stuff - it’s install cable bought along with the ceiling speakers. Fine in the straight conduit (even stuffed in with some Cat6A network cable) but got stuck in the corrugated flexible conduit that I tried to run down inside the redundant chimney. I am now just the old chimney liner itself as a ‘conduit’
In future I will lookout for the conduit grease thanks!
Thank you. Yes, well spotted! It will be going once I have the Cat 6a cable run completed. The socket will be switched out for a basic Russ Andrews un-switched one too.
Thanks, I hadn’t really thought about that but you might spot I’ve got a DC Blocker plugged into the power amplifier because I was getting some interference. Now you mention it I’ll see if it improves when I remove the temporary power line adapters.
