[chadh]

My new house is small, but has a walk-out basement which is partially finished.  We're finishing the basement so it can serve a number of purposes: primarily as the master bedroom.  But there's also plenty of room left to make part of it the primary listening space in the house.

I hope this link works: it gives the rough plan of the space.

http://faculty.fuqua.duke.edu/~chogan/furnished.pdf

Beyond those shown, we won't be putting any extra walls into this space. This means that the effective room is a big L.  The speakers are likely to live at the top of the L, the listening position is toward the corner.  The bed is around the bend.  And there's a big hole in the ceiling to the right of the right speaker - that's the stair well.

The listening area is around 24' long and 17' wide.  I'm not sure how low the ceilings will be once finished - probably a little lower than 8'.  This may be perilously close to an 8 x 16 x 24 room - but there's not much flexibility in the arrangement.  Perhaps the missing left rear wall is a saving grace.

Given the constraints of the space, are then any obvious things I should consider doing while the basement is being finished.  The important words to remember here are CHEAP and EASY.

The walls are currently cinder-block, and the floor is concrete.  Studs will go up, and dry wall over that.  A dry wall ceiling is also planned.  We'll also have to make flooring choices.  Is there anything I should consider in the construction phase?  I'll have a dedicated circuit installed for the stereo.  But are there better and worse flooring options?  Anything cheap and easy to do with the ceiling (that will likely be acceptable to my wife)?

Once the basement is finished, I'm happy to try to cobble together some absorbtion panels and the like.  But is there any special consideration I should make for the fact that there's no wall in the rear left corner of the room, or that there's a stairwell not far from the right speaker?

Thanks in advance for any and all suggestions.

Chad

[JLM]

Chad,


Nice looking space (and drawing).  In my experience the "L" will greatly help eliminate the room dimension multiples issue and will have minimal impact on the overall sound with the layout you have.   The GIK panels I bought are cheap and effective and can be covered with decorative cloth.  (If you don't have enough going on, you could make them yourself, but I found it hard to save much money unless you do a boatload of them.  OTOH if you want decorative colors/patterns it could more easily pay for the hassle.)  IMO every room that you've spent over $1,000 on equipment should have acoustical treatments of some sort.


Generic advice (in order of importance):

Insulate the interior walls around the furnace room.  For $10 this will deaden the sound tremondously.

Consider using insulated flexible duct.  This is a big trade-off!  On one hand it will reduce the sound from the furnace to near zero, but OTOH requires the furnace fan to push air 3 times as hard making it harder/slower to heat/cool the house.  Material cost is somewhat higher, but more than offset by the labor saved.  Obviously the operating cost and/or expense for larger furnace/fans (if you use lots of flex duct) would be much higher.

Replace the drywall ceiling with acoustically drop ceiling.  This would help get you away from the room dimension multiples issue and really help reduce floor impact noises from above (i.e. foot traffic, dishwasher, vacuum).  An alternate would be to install gauge metal furring strips between the first floor framing and drywall.  My contractor refused to do this as he was afraid of it cracking, but I regret not doing it.

Insulate the ceiling (especially if you stay with the drywall ceiling).

Space the studs at 12 inches on center versus the traditional 16 inches.  This will only add about $50, but will stiffen the walls.

Go with 5/8 inch thick drywall versus 1/2 inch.  For an extra $40 it will stiffen the ceiling (see comment above) and walls significantly.


For comfort I highly recommend insulating under the floor slab.  About the only smart thing my builder did was to use a product called insul-tarp (a 12 foot wide double layer plastic sheeting with non-crushable insulation inside) under the slab in place of the typical 1 inch styrofoam (will break as worker pour the concrete) or 2 inch styrofoam (still has gaps and costs more).

[chadh]

Jeff,

Thanks for the thoughts.

There's no chance for the insulation under the slab - the concrete is already in place (as the basement is probably more than half-"finished" at the time of the purchase).  We just need to put flooring over it.  But that's something I'll keep in mind for the next house.

Speaking of which:  any thoughts on flooring?  I don't imagine we'll be able to manage hardwood on the floors here, mostly due to the need for a plywood subfloor, which would eat into our headroom.  So, carpet is looking most likely.  I suspect that putting pergo over the slab would just be way too cold.  But another interesting option is cork.  Any feelings about the relative merits of carpet and cork (apart from the price difference)?

Insulating the furnace walls was something I was already thinking about.  In the diagram, the furnace is in the little square space in the middle of the basement - disturbingly close to the spot chosen for the bed!  So even without concerns for the listening space, the furnace noise was something I needed to address.

I doubt that I'd get approval for any changes in the current furnace arrangements, unless they reduced operating expenses or the noise is disturbingly loud with the duct work that is already in place.  But I shall make discrete enquiries anyway.

The changes to the stud-spacing and drywall thickness seem like pretty easy and reasonably priced options, so I'll definitely look into that.

The ceiling, though...I'll have to do some research to discover exactly what an "accoustically drop ceiling" might be.  Given that it helps get away from the room dimension multiples issue, and has the word "drop" in the name, it sounds disturbingly as though it might give me a VERY low ceiling.  I'm not sure whether this is an option.  But I'll see what my research reveals.

Thanks again!  Once I'm settled in an Ann Arbor, and the basement is finished, you're more than welcome to come around to see the completed product.

Chad

[samplesj]

But another interesting option is cork. Any feelings about the relative merits of carpet and cork (apart from the price difference)?

I really like my cork snap together in my room.  I used a cork underlayment also for extra clack dampening and temp isolation.  If you check around online it can be had for not much more than the nicer laminates at the big box stores.  It feels very nice to walk around on, both impact and temp.  In the winter that floor on top of the concrete was warmer than the hardwood on the ground level above.  I don't know that there are any acoustic benefits because I'm using a line source so I don't have as much of a worry with the floor.

The ceiling, though...I'll have to do some research to discover exactly what an "accoustically drop ceiling" might be. Given that it helps get away from the room dimension multiples issue, and has the word "drop" in the name, it sounds disturbingly as though it might give me a VERY low ceiling. I'm not sure whether this is an option. But I'll see what my research reveals.

Accoustal drop ceiling tile is just the ordinary ceiling tile you see in a lot of commercial buildings.  I have it up in my 2 channel room and it doesn't look too bad.  In terms of bass modes though its invisible so you'd have an 8'9" or more ceiling.  For bass modes you really want to measure from the bottom of the above subfloor.  One nice thing about drop tile is that you can stuff the whole above portion with fluffy insulation and if you go deep enough its a free full ceiling bass trap.  You can hang normal tile pretty close to the bottom of the joists, but if that is too low you can also buy special track to connect to to the joists themselves.

[chadh]

Thanks samplesj.

I really like the idea of cork - we'll have to see if the budget stretches that far (or if moisture concerns in my basement make it unwise).

It seems that this drop ceiling thing isn't so unfamiliar to me at all (especially as I look up and see it hanging above my head in my office).  Is it expensive though (relative to dry wall)?

It's not that I'm cheap.  Honestly!  It's just that I need to choose my battles carefully.  And arguing for significant additional expense to make our basement a nicer listening environment (which is unlikely to be capitalised into the resale value of the house) is a tough battle.  Besides, this space will be the master bedroom as well.  And low WAF can have particularly serious consequences in the bedroom.

Chad

[ctviggen]

If you can do a drop ceiling, I'd recommend one.  You can run wires much easier, for one reason.  For another, they make acoustic panels that you can put in place of the normal tiles.  For instance, see the top most file here:

http://www.auralex.com/sound_diffusor_tfusor/sound_diffusor_tfusor.asp

(These do take an additional chunk of space out of the room, but judicious placement could help with that.)  

As for insulating a wall for sound absorption, you get some but not much benefit for this:

http://www.hometips.com/cs-protected/guides/soundinsul.html

You get an improvement of about 3 in STC (sound transmission coefficient).  You could also use channels (I forget what these are called) that go between the drywall and the studs and dual layers of drywall.

[chadh]

Is there any advantage to installing the drop ceiling only in part of the room, and using the more attractive drywall elsewhere?  (I was thinking putting the drop ceiling in the area above the speakers and the listening spot, while having drywall over the bed and the desk and elsewhere.  Is this likely to cause logistic, acoustic or severe aesthetic problems?

Chad

[chadh]

And thanks for the hometips link.  Lots of good information for someone like me, who doesn't really know what he's doing.

Chad

[samplesj]

Is there any advantage to installing the drop ceiling only in part of the room, and using the more attractive drywall elsewhere?  (I was thinking putting the drop ceiling in the area above the speakers and the listening spot, while having drywall over the bed and the desk and elsewhere.  

Even with the special (read more expensive) directly on-joist ceiling grid holders I bet it wouldn't line up properly with normal sheetrock.   I'd bet you'd have to drop it a few inches and make it look like a soffit.  It sounded like you really didn't have a lot of extra height so that may not work.

If you are willing to pay much more you can get some really nice looking tiles.  Personally I just bought the really cheap fissured stuff.

If you go the resilient channel (R/C) route you need to be VERY careful when you install because if you short too much with screws then it won't really help.

[JLM]

Chad,

Re flooring:  

Check with manufacturers as most hardwood or laminate flooring products won't be warranteed for basement/slab applications.  Don't know about cork.  I've got carpet on pad (as well as in my previous two finished basements) and it probably helps to add some warmth/insulation.

Re drop ceilings:  

Many options are available.  BTW it only has to be dropped 2 or 3 inches.  Yes, you could do just parts of the ceiling.  In our last house we painted the grid (with a 2 inch wide roller) to match the walls and painted the dirty old tiles (spraying them is recommended but it was winter so we rolled them and it worked great to brighten them up a ton and make the 3 different styles match better).  The cheapest is 2ft x 4ft vinyl faced fiberglass, but they can sag over time.  Next is painted mineral wool which is the most popular and comes in tons of options that can really dress up the ceiling (somewhat important in a bedroom as you look up and in larger rooms to break up a big flat surface).  2ft x 4ft is a bit cheaper than 2ft x 2ft and can be gotten that provide the 2ft x 2ft look.

Don't know if you'll have a beam, ductwork, piping, etc. hanging down below the rest of the framing, but the resulting soffit would provide a natural break were just part of the ceiling could be dropped anyway and the rest could be drywalled.  Drop ceiling is real DIY territory, so a chance to actually save money.  That's exactly what our previous house had and the two ceilings were at different heights that you didn't see at first glance.  And it would provide access into the ceiling to replace solid duct with flexible if the solid proves to be noisy.  It would also allow for future addition of wiring, central vacuum, or whatever in the future.  (Wishing now I'd gone ahead with some like I'd thought about when we built.  You can never think of everything.)

I'd avoid the direct joist connection options as you lose all kinds of flexibility in construction, material choices, and having future access.  

Re interior wall construction:

The most acoustically effective, builder friendly option is to use insulated staggered stud walls where the top and bottom boards (plates) are 2x6 and two sets of 2x4 studs are used with each flush with opposite sides of the plates and then offset from each other.  That way sound can only transmit through the wall at the top and bottom plates.  Add batt insulation and your done.  BTW they make batt insulation just for sound insulation, but its very similar to regular batt insulation and is much harder to find.  I've used insulated staggered studs on three projects and it works great (much better and cheaper than rubber spacers/sheets, or rigid insulation sheathing).

Another option to seriously consider is to use an insulated/weathersealed fiberglass exterior door on the furnace room (assuming the furnace is direct vented).  This no cost option will greatly reduce the furnace noise throughout the basement and should have the highest WAF being next to the master bed.

[warnerwh]

Over concrete I'd think carpeting is best. That's what I used.  Besides keeping it warmer it absorbs the sound.

For the ceiling I put up one layer of soundboard(drywall is just as good) then resilient channel than drywall and then acoustic tile.

My listening room is directly under the living room where the HT is. I can turn up my system pretty loud and not disturb the living room except for some bass getting through. I cost me about 400 in materials for this but has been well worth it.  If you need to keep costs down just put resilient channel up and then the drywall. Remember to use drywall for ceilings so it doesn't warp, usually called controlled density of something like that.

Resilient channel is very inexpensive btw.  It's something that you screw the rock to which suspends it. This allows the rock to vibrate without transferring much of that energy to the floor joists keeping the sound downstairs.

Room treatment is mandatory. Bass traps, first reflection points etc should be treated. My room is LEDE with four bass traps. This is the best sound I've heard anywhere and well worth it.  The only downside is the 3"-4" acoustic foam behind, above and to the sides of my system isn't the best looking. If I were to do it over I'd use rigid fiberglass panels with a nice covering over this area.

Wire in at least 2 dedicated lines. Being in the basement your breaker box is probably down there too. It's cheap and easy to do. If you don't know what you're doing though pay someone to hook up the wires to the box and outlets. You can run them yourself, just copy what the electrician who put the other wiring in did so you're upto code.

[samplesj]

Over concrete I'd think carpeting is best. That's what I used.  Besides keeping it warmer it absorbs the sound.

Hardwood and laminates are definately colder, but one of the options he was considering was cork.  Cork is riddled with air pockets so it acts as a fairly good insulator.  I think I mentioned it above, but my cork on the concrete is warmer than the hardwood on the floor directly above.

Even with a reflective floor you could easily lay a rug in the first reflection point.  Also not all speakers are as affected by floor and ceiling choices (line sources for example).

For the ceiling I put up one layer of soundboard(drywall is just as good) then resilient channel than drywall and then acoustic tile.

I'd  be very cautious with any type of spacing between layers.

Generally speaking on the studio construction forums it is not recommended.  You build a three leaf structure and it actually blocks noise less than just a double leaf structure.  There are reports out there that show
layer - air - layer - air - layer
is actually less effective than
layer - air -double layer

Resilient channel isn't a cure all either.  Unless its installed very carefully it will become shorted via screws and provide very little to no benefit.

[chadh]

Thanks to everyone for extremely helpful suggestions.

Chad

[chadh]

These are my current thoughts (and confusions) about the preparation of the space.

1.  Furnace.  Do everything possible to insulate the furnace room: insulation on the walls; weatherproof fiberglass exterior door; look into using flexible duct; maybe even replace furnace.

2.  Floors.  Cork or carpet seem likely to be my only real alternatives.  And they are likely to have similar effects accoustically - so this will be primarily a choice of aesthetics and expense.

3.  Walls.  On the exterior walls, space studs 12" rather than 16", use thicker drywall than usual and (obviously) fill cavity with insulation.  These approaches help reduce the extent to which the walls will operate like a drum.  The furnace room was dealt with above.  The only other interior wall anywhere near the listening area is the one shared with the bathroom.  As this wall is already standing, I doubt we'll mess with it.

4.  Ceiling.  Hang acoustic ceiling tiles if possible.  These will allow the roof to appear higher for low frequencies, and will reduce high frequency reflections.   Otherwise, use drywall.  Consider resilient channel for mounting drywall to the ceiling, and stuffing the cavity between ceiling and first floor with insulation to help reduce noise transfers between floors.  Insulating the cavity between ceiling and first floor will also help reduce low frequency reflections.

5.  Install treatments in corners and first reflection points, maybe other spots too.

Hopefully this sounds right.  Numbers 1 and 2 will happen as a matter of course.  It sounds as though Number 3 requires little extra expense, so I should be able to manage that too.   In Number 4, I suspect that I'll be able to get the ceiling cavity insulated, but the drop ceiling might be a tough sell.  We'll see.  And Number 5 will be addressed further down the track, when we know how poor the whole process is leaving us.

Did I miss anything?

Chad

[JLM]

Don't forget the electrical:

1.  Dedicated audio circuit(s)

2.  Try to get the contractor to use 12 gauge wiring (which allows for 20 amp circuits)

3.  See if he'll provide a separate ground for the audio circuits

4.  Try to avoid dimmer switches throughout the house


(BTW its a ceiling, not a roof.)  

Contractors eat up folks who don't speak their language.

[warnerwh]

A good point has been brought up with the resilient channel. You need to make sure you don't screw the drywall up where the screw goes all the way through the rock and RC into wood, otherwise nothing will be gained. It's not very hard to do this btw.

Another thing I thought is a good idea is to put the RC up asymmetrically. In other words spacing should be different somewhat. You can also angle it a bit.  I did both as to make sure I didn't have one large single resonance in my ceiling.

 You may want to cost out doing two layers of drywall with the RC as opposed to using acoustic tile. I'm sure it would cost less and be easier with just the drywall.  Acoustic tiles are expensive.  To keep sound from escaping one thing that helps is mass and is why I recommend two layers of drywall as it won't cost that much more. The resilient channel will help significantly also.

I don't know how important sound isolation is but there are other options. These though can cost significantly. In my room with what I did I can play my system quite loud without disturbing the living room. Bass frequencies do go through however but a movie or tv can be watched fine.   I have a large full range system with alot of power and it has been important to me that I can listen to it whenever I want.  For the major volumes though I have to wait til the females go to bed which is two floors up.

Best wishes to you and your project. Having a room of your own set up properly is a worthy endeavor.  Once you get your acoustic treatments up and your system set up you'll be surprised how good it sounds.

[chadh]

3.  See if he'll provide a separate ground for the audio circuits.

I'm really out of my depth on these electrical issues, but I thought I'd read all sorts of warnings against using more than one ground for your house.  Am I wrong about this?

Chad

[warnerwh]

Chad: You're correct. You do NOT want to run a separate ground. Just make sure the one you have is well done, clean contacts etc.  Under no circumstances ever do anything other than what is code.  

There can be a differential between grounds and it's a big NO NO. I did research on this myself and now that I know more of what's going on I really see no benefit of having a separate ground. One good ground is all you want or need.

I believe someone mentioned see if you can get your electrician to run 12/2. This is a non issue. 12/2 is code for a 20 amp line and unless your breaker box is bursting at the seams running a couple of 20 amp lines is easy. Whatever you do make sure it's upto code even if you do it yourself.

[JLM]

I'm out of my element with electricity too, but I know that for decades operating rooms were each required to have isolated (separate) grounding (due to the concerns of creating shorts around exposive anethesia).  I believe the real issue is separate grounds on the same circuit.  I have a separate ground for my 3 audio circuits (1 cryo'd hospital grade Hubbell per circuit) with no problems as suggested by an audiophile/electrican.  This was a new house completed last year with a picky (read PITA) electrical inspector.  My audio system is dead quiet to any electrical power abberations.  Hey, if you don't want to go separate ground, and dirty power is a problem you can add a conditioner later.

Standard residental wiring is 14 gauge and per code can be used for 15 amp circuits.  Typical new houses are built with a mix of 15 and 20 amp circuits as some appliances, like our new dryer starts out requiring a 20 amp receptacle.  By code you can't add a 20 amp receptacle to a 15 amp circuit, but my house is full of 15 amp receptacles (that can be changed out to 20 amp receptacles) on 20 amp circuits.  Built ins too, like wells, electrical ovens, or air conditioners require 20/40 amps.  I had a 70 wpc receiver that had a peak draw of 43 amps.  So its no big deal to just use 12 gauge wiring and 20 amp circuit breakers throughout.  As electrical use goes up in general this makes sense.  By code 20 amp circuits can be connected to more receptacles and lights, thus possibly reducing the number of circuits needed.  The thicker 12 gauge wiring is harder to work with and costs a bit more, which is why folks skimp.