Home Theatre & Automation
Jan 09, 2011 9:02 am
just starting to build a HT
It will be a 2 level seating one 6m long 4m wide 3m high
We were planning to do a bulkhead around and place a projector in a recess in the back bulkhead and the rear and side speakers of a 7.1 system as ceiling speakers in the bulkhead .
Is this a problem with heat from the projector??
or vibration of the projector from the speakers.???
I think it will look nicer having the projector in the bulkhead rather than on a bracket dropped from the ceiling particularly since it might be in the visual field of the backrow seats otherwise
2/3 of the way thru the build
Re: Is it Ok to put a projector and speakers in a bulkhead ?2
Jan 09, 2011 7:30 pm
Speakers should be at head height when seated. It wouldn't be a smart idea-vibration in the bulkhead and noise from the top of the bulkhead would just rumble depending on the volume plus sound will be coming from the roof and not the sides.
We have 7.2.....surround sound is surround sound for a reason. Nothing beats hearing a little noise at the back of the room like and little animal etc. Something you wouldn't hear on a normal tv for example.
I am no expert. Projectors get hot as well.
Re: Is it Ok to put a projector and speakers in a bulkhead ?3
Jan 09, 2011 7:35 pm
Forgot to mention.......to avoid any key-stoning ensure you mount the projector exactly horizontal/verticle.
You need to place the projector at the exact distance to create the image size you want. Try to avoid using the zoom function to make the screen bigger/smaller.
Re: Is it Ok to put a projector and speakers in a bulkhead ?4
Jan 10, 2011 3:11 pm
Projectors do like to have some space around them as they do produce a fair amount of heat and if it can't get away from the projector it will get hotter
If you buy any half decent projector these days it would hopefully have horizontal and vertical lens shift so there is no need to use key-stoning (which produces some image artifacts). However, those adjustments (and zoom, etc.) are there for a reason - so you have some flexibility in mounting the thing. Trying to mount the projector in a position where you don't have to use any of it's mounting adjustments is not practical (and a bit silly to suggest it really). Using the zoom to fill the screen and then focusing the lens still produces an image that is perfectly sharp enough to make out the individual pixles from over a metre away - even on a state-of-the-art JVC DLA-X3 (3D!) which has very narrow gaps between the pixels, which I installed just over a week ago.
Also, surround speakers (side and rear) are not supposed to be at head height - they are supposed to be at least 2~3 feet above head height. The front speakers are supposed to be as closed to head height as you can get them though...
Audio Visual Dreams
The Complete Custom Home Theatre Company
Re: Is it Ok to put a projector and speakers in a bulkhead ?5
Jan 10, 2011 5:25 pm
Okay yes 2-3 feet above head height is good but they are going to be better at "head height" than mounted in the bulkhead.
Some people will prefer there rear speakers higher or lower than head height. Find whatever works for you. You don't want the speakers too high. Seated ear level or a bit higher. Whatever you prefer.
Re: Is it Ok to put a projector and speakers in a bulkhead ?6
Jan 11, 2011 4:15 pm
Just my two cents, but I agree with the keystoning side of things and the vibration issues associated with speakers in the vicinity of the projector. Most projectors these days have a very flexible vertical lens shift (approx 100% on some models) meaning that the projector can sit well above the center of the screen. Just check the horizontal lens shift, as I have a Mitsubishi projector and it has 5-10% only, meaning that the projector needs to be closely aligned horizontally to the center of the screen. Again, be careful about the heat build up side of things. As nice as a recessed projector looks, you are inviting disaster if you enclose it too much. Other option is to introduce forced ventilation, but then you run the risks of dust infiltrating your projector (LCD issue, not a DLP issue).
My limited understanding of speakers for surround use is that they should, by their nature, provide a diffuse sound field that does not locate the speaker to the listener. You should not be able to pinpoint the location of the speaker. For this reason, Bipole or Dipole speakers are the best bet. They should be mounted just above head height. They fire sound in two directions, meaning that you get a more authentic, enveloping sound field. These are the speakers that I would recommend.
Best of luck with your installation.
Re: Is it Ok to put a projector and speakers in a bulkhead ?7
Jan 19, 2011 10:52 am
thanks for the advice
saw one at Len wallis on w/e
projector sits well forward into the room but has a bulkhead of sorts coming out to reach it and disguise it from seating positions
2/3 of the way thru the build
Re: Is it Ok to put a projector and speakers in a bulkhead ?8
Jan 20, 2011 9:35 am
Hi there Mike,
In my readings, a number of the theatre builders in the USA are constructing 'hush boxes' around their ceiling mounted projectors in a black acoustically transparent material which allows better airflow around the projector. This tends to make it 'blend' into the roof a little better rather than just standing out like...well you know what!
Other option is just to incorporate a small exhaust fan (available from Jaycar etc I would imagine, that would suck the hot air away from the projector. Having said that, I have seen plasmas mounted above fireplaces. Yes, you can do it, but I would really not like to think about the years of service doing so will take off the operation of your equipment.
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