Acoustics of an uneven ceiling

[Samk1234]

Hello,

I'm currently searching for a new home and picking one with the right listening space is the top priority.

Some options I've looked will have ceilings where the drywall will drop at least a foot or two. I'll normally see this along the edges of the ceiling, but sometimes going through the middle as well.

How bad is this and why? Should I aim for a smooth ceiling?

I've attached an image to provide an example (this image is not of a room I am considering)

 

[Trdat]

In terms of a smooth ceiling, tapering or vaulted someone hopefully will chime in and give advise(some are better than others) but if we take it from an absorption/reflection perspective it all depends on the type of cavity, its depth and if there happens to be any fiberglass/mineral wool for insulation within it. Of course if it is a brick wall it could cause problems but I am pro reflections you just have to control them if it is solid wall. The only real problem with a cement wall is that it could force you to add more absorption to make up for what the cavity could have absorbed, that's all. Personally I am totally over a symmetric room but that's personal not scientific.

A cavity with plasterboard can act as some type of helmontz absorber, not in its true terms but it could absorb frequency specific and in general have some absorption effect, you will need to do REW testing for that room to understand what is going on. In this room though the column does look like its a retaining wall or retaining structure so it might be cement?

Either way I wouldn't worry about it, in this room or in general but it will depend on the room. Essentially, you have other acoustic goals you need to get to that are more important than what problems an uneven ceiling or column could potentially cause.

Ideally if we take a ceiling or wall that is out of place, in general its all about the strength of the reflection and the time it takes to return to the listening position from that wall that could be an issue but understanding this phenomenon and solution is something you have to dig into a little yourself and then get back to us.

 

[oivavoi]

My own experience so far in life is that rooms with uneven ceilings generally sound good acoustically (provided some furnishing, carpets, etc), usually better than rooms with flat ceilings.

The reason may be that parallel surfaces create more echo than uneven surfaces. The sound waves between two parallel surfaces will basically go back and forth uninterrupted, kind of. When one of the surfaces is uneven (or if something else gets in the way) the sound waves starts to bounce around in various directions instead. Just think of the difference between clapping your hands in a room which is completely empty, and clapping your hands in a room where you have put some amount of chairs and tables, which then get in the way of the sound waves. The difference can be quite dramatic.

So if it was me I would probably prefer a home with uneven ceilings, all else being equal. The most important thing though is to have a listening room where you can position the loudspeakers optimally with regards to adjoining surfaces and the listening position (ideally 1 m out from the wall, also 1 m away from side walls, in a triangle with the listening position. this may require loudspeakers which can be moved out from the back during listening sessions). The layout of some living rooms makes that difficult.

These are just thoughts from a happy amateur, though, proper acousticians may give you better advice. Good luck!

 

[Hipper]

My understanding is that an ideal ceiling is one that is low where the speakers are and goes up towards the listener.

A key issue regardless of ceilings is how your speakers behave - their dispersion pattern. I have your typical 8" high ceiling but my speakers have ribbon tweeters and mid range drivers. These drivers are said to disperse around thirty degrees so with the distance I sit from them - 1.5 metres - I'm not troubled by ceiling reflections. I even experimented with absorption on the ceiling and I couldn't hear any difference - I didn't do any measurements.

I feel the horizontal symmetry (walls) of the room is a much more important consideration.