Buying a New Home With A Good Sounding Media Room 
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Written by Bob Hodas   
Sunday, 01 August 2004

AV Education on RHT

Buying a New Home With A Good Sounding Media Room

Written by Bob Hodas

A number of years ago, a good friend of mine built a beautiful new house in Napa, California. He had made a bundle working for a professional audio company that had taken the industry by storm with a forward-thinking new product. I went up to visit him and was I ever impressed with his home. It was spectacular in almost every aspect. What wasn’t spectacular were the acoustics of the room in which he set up his favorite speakers. He set the system up in his vast living room, which had an Rt60 (reverb time) that rivaled my old high school gymnasium. I could see for this discerning listener that making his music playback match the grandeur of the overall home was going to take a small miracle.

In this feature, we will address some of the issues you should think about when you start looking for your next home. Concerns about mortgages and bathrooms and where to put the in-laws often reign over which room your theater or music system will live in. With the following key thoughts in mind, you can have the best of both worlds.

Here are some of my initial thoughts on the basics of what you should look for in a new home with a good-sounding audio room.

1. I advocate a rectangular room for the best audio performance. I don’t like L shapes or square rooms.

2. Avoid large unsealed openings to a walkway or another room. A good room should have doors – not open entryways.

3. Look for symmetry, no bay windows on one side unless that is the wall the speaker’s back will go on. The same goes for a fireplace. Things like bay windows or an opening on one side can ruin the imaging since the first order sidewall reflections will not match.

4. A cathedral ceiling can be a bad thing as it can focus reflections back down into the listening area and bass can build up in the peak. A slanted ceiling, like at my house (Sound Tips 4), can be a good thing as long as the speakers are at the low side of the ceiling. The angled ceiling will throw some of the first order reflections to the back of the room and away from the listening area.

You should also refer back to Sound Tips 2 regarding room size. You don’t want a room with a bunch of ugly modes piled on top of each other. Would I venture a minimum size? That’s a difficult question since I’ve heard some very small rooms sound spectacular, but I think you want at least a 13.5’ x 12’ floor plan, assuming an 8’ ceiling. For me, the higher the ceiling, the better. Considerations are more complex if you plan to put in A/V and have two rows of seats. Even though the best placement for the speakers may be the long wall, this may not work out for the projector throw or seating.

Sound Isolation
The issue of sound isolation is going to affect you in a big way. Unless you live alone, you generally can’t make as much noise as you want at all hours of the day or night. Addressing isolation in an existing house structure is a difficult issue. Most homes are not built with much sound isolation in mind and the hollow walls and stud spacing are not ideal. Unless you are prepared to build a room within a room, you will never get yourself totally isolated from the rest of the house or your neighbors. Some of my clients know their neighbors and made arrangements to listen from the neighbor’s house while they had the music cranked up. This will give you a good idea of how much work you have ahead of you.

There is not much you can do about wall construction unless you decide to tear off the existing drywall (not a bad idea and not as expensive as you might think). If possible, look for minimum 16-inch stud spacing, not 24-inch. If you’re stuck with 24-inch spacing, add extra studs to stiffen the wall. Most houses are going to be built with sheetrock. Some basic isolation can be added to the walls and ceiling simply by adding another layer of mass. If you’re going to go to this amount of trouble, instead of using 5/8” sheetrock, go for some MDF or Wonderboard. These materials have much more mass than sheetrock. Be sure when you install an extra layer that it is glued and screwed and that the new seams do not overlay the existing seams. If you can afford it, there is a new material on the market that has a significantly increased amount of isolation. It is called QuietRock and QuietWood and you can get more information about it at here. I recommend it and you may find that you will simplify the construction process with this material. Any of these wallboards can be made more effective by floating them on resilient channel. This creates an insulating air space and isolates the new wall movement from the existing wall, very effective and of course more labor and money. There are various forms of this channel, so shop around. Here are some links to get you started: Silent Source or Kinetics Noise or Auralex.

For that matter, putting the audio room in a basement will solve some issues with wall stiffness as well as isolation. You might have to deal with venting of radon gas (because it causes cancer) and other less harmful but truly smelly elements from a basement. A dedicated small HVAC system can be a great addition to a dedicated theater room. The newest AC units can get your room cool much more quietly than units from even five or 10 years ago. When you are paying a premium for the most resolute audio gear with the lowest signal to noise ratio, it is a shame to waste some of the advantages in a room with a lot of noise.

If you are lucky, you might find a room that has wood on the walls. I’m not talking about that fake plastic wood panel crap, I mean real wood. Wood has a rich sound all its own. It tames the high frequencies just a bit and, to me, creates a very smooth, natural sound. On the opposite side of the spectrum, walls made of windows are very difficult to tame. Hard plaster walls can be tough, too (see below). Using thick drapes or fabric can help soften the blow of hard surfaces but when looking for a “perfect” room, do what you can to say no to that “Miami Vice” house built in 1986 with all the glass brick.
In a perfect world, you want as few windows as possible. This will be especially true if you are going to put in a projector and need the room dark. Of course, there are also isolation issues with the neighbors to consider. A house that has new, double pane windows is a perk because it can keep out noise from the outside world, as well as help keep the room more moderate in terms of temperature. If you live in a setting like Manhattan, you might need to really look at installing serious window solutions in order to get your room quiet. I recommend finding a window professional for advice in your area, since the solutions we use in studios are very expensive and typically custom-built.

Think about a windows contribution to overall reverb time. If you do have a big window like I have at my house (Sound Tips 4), hopefully it’s on the front or back wall and not on the side. Sidewall windows can be problematic for reflections and therefore for imaging. A window in the front offers the possibility of allowing some of the speaker’s rear-firing low-frequency energy to pass out of the house, thus eliminating loading and out of phase reflective energy at the listening position. Speakers designed to be flat in free space work well in this situation.

On the cheap, you can do several things. Replace your interior door with a solid core exterior door. Make sure you address the air spaces around the doors with some type of insulation as well. Remember that any little air space will leak sound like a sieve. Understand that this applies to your HVAC ducts as well, but this is something most home music room budgets can’t deal with. If you have more money, you can find some medium-priced, mid-quality doors being used in home theaters like those at Owens Corning.

If you have the space, a method used in recording studios that really helps with noise isolation is using two doors with an air space between them. While commercial recording studio doors are utilitarian in design, there is no reason why you can’t design the two-door system into a more ornate entry-way that is themed or designed to match your theater or music room. The effect of these doors can be impressive and I would never expect to find them already in a home. But you might keep an eye out to see if you could retrofit them to a house you were considering investing in.

I like the look and feel of floors covered in rich Corinthian leather. No, sorry, wood, I meant wood. For the same reasons I like wood on the walls. I don’t like cement, Mexican tile, stone or linoleum on the floor because they can add too much reverb time to the room. Of course, you can always carpet any of the above floors and at a minimum I would recommend large area rugs.

Unless you plan on floating or decoupling your floor from your foundation (an expensive option), you will have to live with structure-born transmission. It is tough to control. An alternative is to treat the ceiling in the room below you with some QuietRock, but that will still only give you minimal low-frequency isolation, since the bass will travel throughout the house in the supports.

Some Reverb is Good – Too Much Reverb is Evil
As I mentioned above in several instances, reverb time is very important in your listening room. Small room Rt60 measurements are not easily quantified but common sense and simple listening tests tell us that shorter is better. My friend’s room described above had tile floors, high angled ceilings and plaster walls, with a large floor plan that incorporated a dinning room and sitting room. It was just a big reverb chamber. Rooms with long reverb times have very poor measurable coherence. Common sense says that the more hard surfaces you have in a room, the less coherent the sound will be. If you can afford it, there is a product from RPG Inc. that my friend could have used on his acres of hard plaster walls. Believe it or not, it is a sound-absorbent plaster. (Click here to check it out.) As stated above, solutions will include area rugs and draperies.
While electricity is not my domain, it is something you need to think about. How old is the house you are buying? Does it have grounded outlets? Mine didn’t, because it was built in 1956. If not, you will want to run a star ground to all of the outlets in the room. Additionally, can you run a separate circuit for the listening room? There must be enough power at the main breaker box for this so ask an electrician or the inspector. You will want to consider if there is room to put in a balanced power box or at least some power conditioning as well. Before you move in, upgrading your AC service and creating multiple dedicated circuits for your rack, amps, projectors and lights can be a worthwhile investment of a few thousand dollars. You can reduce the chance of hums, noise on the AC line and even equipment failure.

I hope this column has been informative and will help you to enjoy hours of listening in your new home. Most likely, no room is going to be perfect unless a home has a purpose-built home theater or a home studio. Compromise is going to a part of your vocabulary in every home you might look to buy. With the tips listed above, hopefully you now have an idea of what to look for in a new house, so that you will ultimately end up with a great-sounding room. Also don’t be afraid to call in a professional to get a second opinion before you write that offer. A good CEDIA dealer or local acoustician can help determining the quality of a room. I, like other studio tuners, offer off-site consultation service that include drawings, plans and basic recommendations for making your room great.

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