I encounter this problem a lot where not enough ducting is planned for between the rooms. If I get involved in enough time, I always have a chat with the architect to ensure that there is enough ducting provided but, most of the time, it is too late and the floor has already been done. Bear in mind architects don't really like putting big ducts in as they may affect the structural or acoustic performance of the control room.
The structural problem may be due to the massive amount of building materials in the walls and ceiling required to sound insulate the control room. If the floor is weakened by having a large space in the floor, the control room (CR) floor may not be as strong (this happened recently). Acoustically, that big gap may cause resonance problems in the CR and also allow sounds to travel between rooms unless carefully sealed up with expanding foam etc.
Bear in mind you
may need quite a few cables between the CR and Machine Room (MR). If you had all the SSL computer cables plus ProTools and/or Analog tape machines in the MR, a few big effects units plus tielines, remote cables and other stuff like digital, video, Cat 6 etc, your ducting may need to be quite big especially if you want to be able to pull out complete cables one day when you sell the SSL (and buy another one of course!) without having to chop them (never cut at the DL end as they could be sold on).
Also keep the analog cables away from the other stuff in which case I would possible recommend having metal trunking if you can afford it. Although more expensive, an advantage is that you can connect it to the technical earth as well by drilling a hole and fitting a cable to your tech earth point. This version can be in something like 100mm widths so the cables are separated which is another good point. You could therefore have a 300mm wide duct separated into 2 or 3 sections. Metal ducting is not great for pulling ribbon cables through though and I would suggest rounding the corners and maybe even fitting some thin (4mm) plywood into the ducts to avoid any cables catching on the corners and metal bumps inside it.
SSL supplied their cables (console to computer) prior to any console shipment so they could be laid into the floor area but I have heard of some bad cases where the floor was already completed or the ribbons ended up with a nail through them as the floor wasn't finished before hand. A removable top for the ducting would be ideal from a wiring and installation point of view but wood flooring, fitted carpets, structural and acoustic problems may prevent this. In any event, leave enough room in the ducting to install more cables and remember,
a studio is never finished!
With the possible looms I mentioned above being laid in, you could end up with the following cable looms in the duct:
DL's 11, 12, 21, 22 (multi returns and sends), 41 and 42 (analog machine track remotes if needed), another one or two 24 or 32 pairs for MR outboard and tielines, 1 or 2 SSL power looms plus 5" TV cable, SMPTE, loads of 50 way ribbons plus the 5" TV 20 way and any other smaller video, data, digital and remote cables if required going via the same route.
Also, if one of your live rooms or booths leads on from (next to) the MR, you have all that stuff to go through the same ducting as well.
Hope this helps. I attach a picture of 2 x 48 way multicores going through a 4" pipe into the MR at a recent studio. You can see how much room they take up and they just deal with 48 channels of ProTools records and replays (DL's 21, 22, 11 and 12)!
Finally, if your ducting can not be accessible, always add a sturdy draw wire twice the length of the ducting so you can pull more cables through. I would also suggest repositioning it a few times as it starts off on the bottom and then you gradually have a weight of cables on top of the last ones you pulled through making it harder each time. Gravity is responsible for this as cables lie on the floor!
Regards from Jim Lassen (
www.profcon.co.uk). Also on
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