2Designing a Home Theatre Room & Lounge

I have been look­ing to design a new home theatre room, and research­ing this top­ic has led me to a few pre­lim­in­ary con­clu­sions.  First of all, there are lots of dif­fer­ent ideas out there about home cinema room shapes!

Home Theatre Room & Lounge

My home theatre room needs to also func­tion as a lounge, so a stand­ard rect­an­gu­lar shape is likely.  As the ceil­ing is a fixed height of 8’ (2.44m) I will be basing the oth­er dimen­sions around this.  Ideally I’d like a good size to also accom­mod­ate all the usu­al fur­niture found in a lounge.  This means a room of approx 20 sq m floor area, which with a height of just over 2 metres means a room volume in the region of 50 m³.

Screen Size

I will be using a HD pro­ject­or with a large screen size, around 70–80″ (2m), and sit­ting at a dis­tance of about 3.5m (11.5′).  This is well into the zone where 1080p becomes advant­age­ous as illus­trated by the graph.

Room Ratios, Standing Waves & Room Modes

As Axio­mAu­dio explains, the most basic advice is to avoid home theatre rooms with dimen­sions with com­mon denom­in­at­ors – oth­er­wise you suf­fer from stand­ing waves at cer­tain frequencies.

The Golden Cuboid is based on ratios of 1 : 1.6 : 2.6 which is also the ratio recom­men­ded by lots of oth­er sites, includ­ing DIY­Movi­eRooms.

Anoth­er com­monly recom­men­ded ratio is the Sep­mey­er Room C, which has a ratio of 1 : 1.6 : 2.33.  The Sep­mey­er room ratios are com­monly used for Hi-Fi & Audi­o­phile listen­ing rooms.  They are recom­men­ded by PCper and Cinema­Source

VIP­Cinemas, based on sim­u­la­tions car­ried out by Salford Uni­ver­sity, offers sev­er­al ratios, includ­ing 1 : 2.3 : 3 and 1 : 1.6 : 1.8

Fur­ther research seems to indic­ate that no set of ratios is per­fect, espe­cially in small home sized rooms, which aren’t big enough to avoid room modes regard­less of ratio.  Any of the above ratios should offer a reas­on­able solu­tion.  I plan to use the Sep­mey­er Room C as it is well tried and tested, and I sus­pect a lot of Hi-Fi equip­ment is designed with listen­ing rooms in mind.  It is also handy if I go to listen­ing rooms to listen to poten­tial new equip­ment, as I will be listen­ing in a room with the same ratios as mine.  Finally, it works well because a room 2.4m high will be approx­im­ately 4m wide and 5.5m long which is also a good size for a lounge.

Most recom­mend­a­tions are for the dis­play to be on the short­er side on the room, how­ever, for the room to func­tion as a lounge as well, I plan to lay it out with the screen on the long side, so there is room for a very large dis­play and for the speak­ers to be well spaced, as in the image.

Furnishings & “Treatments”

Regard­less of room dimen­sions, to get the best sound will also need a room that isn’t just a con­crete box.  Com­plex room shapes, like slop­ing ceil­ings can help.  Soft fur­nish­ings, thick car­pets and cur­tains can also help reduce stand­ing waves and over the top reflec­tions.  The key is in the right bal­ance – too much damp­ing can lead to a dead sound­ing room.  There are thou­sands of firms out there offer­ing many room treat­ments.  Some are genu­inely use­ful, some are a sub­stan­tial rip off and oth­ers are utter snake oil.  At least ini­tially I plan to get a nice car­pet and cur­tains fit­ted, and those, com­bined with some stand­ard room fur­niture (mainly sofas) will hope­fully do the trick.

Speaker Placement

The place­ment of speak­ers is a much more widely agreed stand­ard – as detailed in the image.  The height of the fronts should ideally be ear height, and the rears should be 2′ above ear height – which is approx­im­ately ear height when standing

This art­icle is a work in pro­gress.  We will con­tin­ue to update it as we find out more inform­a­tion and try more experiments.