AIR CONDITIONING

If you've built all the rooms of your studio correctly you will have airtight sealed rooms so the opportunity for external air to enter the building has been totally eliminated. You must therefore have some form of air-conditioning to not only keep your air temperature constant but to supply fresh air. An air conditioner consists of three components.

• The compressor unit that creates the cool/heat.
• The fan unit that moves the air.
• The Ducts that distribute the air.

These units can be assembled in three ways

• The standard free standing unit that has all units in one.
• The split system where the fan unit is in the room and the compressor unit is outside.
• The fully external system where the fan and the compressor are external and the air is circulated via ducting.

The following must be considered.

• Number of units. You must have one unit for the control room and a separate unit for the studio. I've found that when you use one unit for both you land up with a nice temperature in one room whilst the other room freezes. Never underestimate how much heat normal recording equipment produces. If you add up the wattage of all your gear and imagine a heater of the same wattage you will find that you have around a 2000 watt heater going in your control room all the time whereas in the studio the only heat is the occasional guitar amp and body heat. Consequently if the thermostat is in the control room when the control room is fine the studio freezes. I recommend two separate units.
• Type of unit. There are three types of air-conditioners available as previously stated. The main difference here is that only the fully external system can add fresh air.
• Noise Factor. Obviously having an air-conditioner grinding away in a studio is not much good if you are recording quiet instruments but if you've got a metal band in there who cares!! Lots of home studios have a split system (That's when the compressor is external and the fan unit is in the room) There is no air exchange and if you are recording quiet instruments you just turn it off for a while. It is the cheapest system and, to be honest, the most common. Fresh air is achieved by leaving the doors open when isolation is not required.

I think that if you check your local building codes you will find that because your rooms are totally airtight they will require you by law to have a fully ducted system which adds fresh air.

To install this system you will have to breach the air seal that you have carefully created but there are ways to get around this. The typical ducted system works like this.

TYPICAL AIR-CONDITIONING UNIT

The above drawing shows a typical external system. The compressor and fan are in the unit externally and the ducts send and return the conditioned air.

The Ducts. The typical duct found in a home air-conditioning unit are OK for the standard home studio. They normally consist of a aluminium foil pipe wrapped in fibreglass and plastic. The external ducts on the other hand must be soundproof and are typically made from galvanised iron boxes lined internally with sound absorption material. Just remember that the larger the duct the quieter it will be.

The Noise Factor: The slower the air in the duct the quieter the air-conditioning system will be. Some of the top studios have ducts which are 1 - 2 M (3 - 6ft) wide and the air moves slowly within the duct. This stops the hiss you get when the air enters the room via a duct.

As stated the seal between the external duct and the internal duct is very important. The common way is to join the two ducts with a flexible join so that the two ducts aren't mechanically linked.

FLEXIBLE JOIN BETWEEN DUCTS

The important factor here is to make sure that it is totally sealed. The flexible joint can be made out of a product that is made from vinyl impregnated with lead. Ask your air-conditioning company about it, they will know. This gives a flexible soundproof seal.

Fresh Air: I must say something here about adding fresh air to a system. I have found that the formula used by most companies for adding fresh air doesn't add enough. When you have a control room with a producer, engineer, musos and a few hangers on the amount of fresh air added is usually insufficient and by halfway through the session everyone is yawning. They usually add about 15% fresh air to the system but I would urge you to consider adding up to 25 - 30%. This is more important when you have a fully sealed system in a city building where there is usually no external windows and the outer office/hallways etc. are fed by the buildings own system. Creativity requires plenty of fresh air!!!

Obviously the air-conditioning can be extremely expensive.

No doubt your budget will be the determining factor.