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mik_m

New HT build – please help 😊

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Hello Gurus

 

My wife and I are building a new house and planning a dedicated HT. We have a lot of flexibility with the room design but we’re really not sure how to set it up. What we have so far:

-        6910 long x 4210 wide

-        Rear of the room has double glazed windows which are the smallest we can use in the space. Plan is to curtain the entire back wall.

-        Front of the room has a 90mm false wall to allow for in-wall speakers. But we could create a cavity for floor standing speakers behind the screen if there is enough length in the room and it makes a big difference to the sound

-        Sides of the room are bounded by an external wall and stairwell next to a hallway. To keep the room size uniform, we are planning to install storage after the stairwell. At this stage we have these storage areas opening on to the hallway but as they’re 1m deep we can split them down the middle and have some opening to the inside of the HT. We have already claimed a 1000 long x 600 wide space in this storage area for an AV rack at the front of the HT that opens both sides so we can access both AV controls and cabling.

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1733994799_HTplan.jpg.4f6a34886e030cc7d7ce921a94d5663d.jpg

 

Where we need your help:

-        Our biggest problem at the moment is how high should the ceiling be? We can set it at 2700, 3000, or 3300. We’ve spent days researching this and using ‘the golden ratio’ it looks like 2700 is the way to go but we don’t want to stuff up the room by making the wrong call on the plans. If it’s relevant, we would like to put in a star-field ceiling so maybe that needs a bulkhead around which might affect the height? We also are including a second row which is approximately 300 high but again we have flexibility to adjust this.

-        Any recommendations on screen size? The problem we have come up against is screen size is calculated using viewing distance and viewing distance is calculated using screen size. It’s a catch-22 and as we don’t know either we don’t know where to start. If we knew the screen size then we could calculate the position of the first and second rows.

-        Any recommendations on seating position? The front row is where we will usually be seated and we would like to put in a type of chaise so we will be tuning the room for this row. But, we also want the rear row to have some experience of the sound which we think means bringing the seats off the rear wall. If so, how far?

-        How high should the riser be for the rear seats? Our guess is 300.

-        How far apart should the first and second rows be? Is there a standard?

-        Any recommendations on speaker type? Our immediate thoughts were to go in-wall because my wife doesn’t want to be tripping over speakers. But, researching (again) last night we came across a setup where all the front speakers were behind a fold down screen. Best guess is that the owner had a 600 deep cavity in the front of his room and put floor standing speakers and his subs in there. Do we have enough length in our room to do this? Should we do it? Is the sound from floor standing speakers that much better than in-walls?

 

We know this is a lot to ask and appreciate any help you can give. We have literally spent the past week trying to sort this out and the more calculators we use, the more confused we get.

Thanks for any help you can provide.

Cheers,

Mik

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First thoughts;

 

  • What's your budget for construction, sound gear and projector? Do you need sound leakage minimised? If so the budget just went up a lot.
  • Putting your rack where it is will mean it will be behind your left channel speaker if they are in the room or lost completely if having a perforated screen. I'd suggest putting it in the store area under the stairs where it's easily accessible, that's the same area I used in my build. Hide the equipment behind a door and plan ventilation so gear doesn't get too hot
  • Depending on budget, an AT (acoustically transparent) screen is the best result as all speakers are hidden, but also most expensive. Side and rear speakers will go behind fake pillars ideally. You have room to do this.
  • My room is a bit smaller at 6x4m with 2700 ceiling height. I'd prefer higher ceiling and then build bulkheads for AC/ventilation. I did it on the cheap renovating an existing room and cost me roughly $10k just in construction without any acoustical design or treatments. I still wake my daughter who sleeps above if I get a bit greedy with the volume.
  • for a room of that width a 130" scope screen is the biggest you'd probably want.
  • My riser is 300mm high. These can be made into effective bass traps too. I wish I had done that.
  • If room is for movies/tv only, I'd recommend Krix SX (or higher ranges if budget permits)on wall speakers behind an AT screen http://www.krix.com.au/on-wall-sx/
  • you'll want your rear seats about 1m from the rear wall if possible. 1 is for better sound generally, and you may also need a 2nd sub back there too
  • Based on my 6x4 room with speakers in the room, my seating position is 3.5-3.8m from the screen which works well but may not with 1m more room depth as it would be close to the centre of the rooms depth.
  • Plan lighting and AC ducting to go into bulkheads rather than into the ceiling cavity if you are worried about sound leakage

This may give you some ideas

Perhaps again depending on budget you might want to get an acoustical pro in to plan it for you. Wavetrain are highly regarded and Red Spade Audio who are members here could also help out more than a lay person like me.

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Hi blybo

 

Thanks for the comprehensive reply. I checked out your room and it looks awesome 😃

Budget for our AV gear is $30-40K which we think will get the job done. We also allowed for two sheets of Fyrchek to the internal walls and SoundScreen between the studs. Any tuning after the room is set up will be extra I guess but we were hoping to design the room in such a way that we wouldn't have to treat it that much after construction.

 

Good point on moving the AV rack, so I'll take that on board and set my ceiling at 3m to allow for bulkheads. I'll also stick with the 300 riser height as it works for you and start with a 120" screen to see how that fits. Maths was never my strong suit but I think I can work out viewing distances with this info. If I have too much room left over then I guess I can increase the screen size and try the maths again.

 

Funnily enough I was looking at the Krix Epix for the front left, centre and right speakers but was told to move to Martin Logan Edge. It's a difficult choice because hardly anyone has in-wall speakers installed that we can demo and I'm not sure if the extra $$ is worth it. Time to read some more online reviews...

 

I'll have a go at putting this altogether and if I get stuck then either Wavetrain or Red Spade Audio will be getting a call.

 

Thanks again for all your help.

 

Cheers, Mik.

 

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hey mik,

 

how critical do you want to eliminate sound leakage? If you want to do the best you can you should consider using whisper clips or resilient mounts and green glue to improve overall performance. 

 

I'm building a new house next year as well and my home theater is almost identical to yours! yours is 910mm longer LOL.

 

I too was stuck with the same questions you are asking so I ended up hiring a professional (Shawn Byrne, Quest Acoustical Interiors) to do my design. I elected for the basic design (1800USD) this covers mainly the science behind it rather than the total design. It doesn't cover everything like HVAC, electrical, and build out details, But I'm hoping that get any missing info for the net.

 

for your overall budget, I would seriously consider getting it designed. That way you get exactly what you want and well designed so it functions correctly.

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To be honest I haven't really considered sound leakage but not annoying the neighbours is a given. It's a new build so I don't need enemies as soon as we move in. I figured two layers of Fyrchek , SoundScreen, double glazing, and a solid and sealed door should cover it. I'll also add whisper clips or resilient mounts and green glue to the list.

 

Up until today my goal has been to make sure I get something decent for the money but maybe I need to rethink how I achieve that. I figured the room design was the first step in this process and perhaps that's where the professional help comes in... It's hard to know because others have said just build the room and correct it with acoustic panels later. This is why I'm confused.

 

I built a HT before but with a much smaller budget of 10K. It turned out OK. It's taken me a long time to save for this one and even longer to convince the missus that the increased budget will be worth it. I'm just trying to cover all bases to make sure I don't stuff it up 🙄

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Clip and channel the entire room. If you must have windows, get the double glazing with a thermal break - not perfect, but good enough.

 

If it were my room, I'd put the rack in the "store" and build a false wall with an acoustically transparent screen

 

Consider another door where the main door is, that'll work much, much, better compared to a single one. Airlocks work great. Seals all way around and bottom - both doors.

 

IMO, the higher the ceiling the better

 

If you think you might want to get acoustic treatments, plan for it now, otherwise you'll end up with panels etc done in an ad-hoc manner, which IMO looks crap.

 

Consider a layout service, money well spent. I can recommend these guys https://questai.com/design-package-comparison/ or The Erskine Group

 

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My room is slightly wider but just as deep. I packed in 8 full recliners with same 300mm riser for rear. Hooked up 7.2.4 wiring and using 140” scope acoustic transparent screen. I thought 130” was fine but 140” is better. I’ve got 3m ceilings with a central dropped bulkhead with 4 ceiling speakers, led lighting trough and a/c ducts running into this bulkhead. Projector sits on a high shelf built into back of room and gives most flexibility for future projector upgrades. 

Wiring is all prewired. Subs located front and rear.

I have double brick construction the sound is just audible standing outside at -12db level. 

Your room is very similar to mine it’s uncanny.

I installed two extra lan cables to the projector area and also ran extra lan cables to the front seats. Theses are used for network connection to projector and also doubles as USB extension which I use for Xbox and media connections to the rack.

I hook up the steering wheel to the USB baluns so you don’t trip over any cables.

Also stick 4 power points behind the front seats (on the face of riser) as this gives more options for power recliners, bass shakers, general power or charging etc.

Is there a reason why your windows are not centered to the room?

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hi Mik,

On 12/10/2018 at 12:02 PM, mik_m said:

Our biggest problem at the moment is how high should the ceiling be? We can set it at 2700, 3000, or 3300. We’ve spent days researching this and using ‘the golden ratio’ it looks like 2700 is the way to go but we don’t want to stuff up the room by making the wrong call on the plans.

 

On 12/10/2018 at 7:44 PM, Peter the Greek said:

IMO, the higher the ceiling the better

agreed - bigger is better, don't shrink a dimension to hit a "golden ratio"

 

On 12/10/2018 at 7:31 PM, mik_m said:

It's hard to know because others have said just build the room and correct it with acoustic panels later

better to design it right first - especially if isolation is a priority - you can't add isolation later.

 

On 12/10/2018 at 1:18 PM, blybo said:

My riser is 300mm high. These can be made into effective bass traps too

this is a good idea, especially if you've designed in good isolation, which can keep bass in the room requiring treatment

 

On 12/10/2018 at 12:02 PM, mik_m said:

Is the sound from floor standing speakers that much better than in-walls?

In wall speakers can sound better if done right - no Speaker Boundary Interference Response (SBIR) from the front wall

 

cheers

Mike

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Forget the golden ratio - it's only an issue if the room dimensions are close to multiples of each other.

 

In wall speakers are a great idea, or a transparent screen with regular speaker behind - it makes the room feel bigger, and can eliminate diffraction.

 

Planning ahead at this stage can allow you do something which are difficult otherwise - locating of subwoofers, bass traps, in wall speakers, etc.... can all be done now at reasonable cost ..... where as later it's difficult/impossible .... and these things (subwoofers, bass traps, speakers, etc.) will clutter up the room.

 

 

 

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Hey WasM

Your set-up sounds a lot like what I am looking for. I was thinking a 120 screen but might increase it now that I know you can squeeze larger it in your room. Just need to make sure the in-walls still fit afterwards.

We did have a large central window but the architect suggested we move to two smaller ones. Ideally, I'd have none but blah blah blah building codes 😉

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I've been doing a LOT of reading since starting this thread and am now convinced I'm going to have to get the professionals in. Still getting conflicting advice on the ceiling height though. I moved it from 2700 to 3000 already but can go to 3300. It's just that this seems so high... I'm planning a bulkhead but damn that's a tall roof. Anyone have any thoughts on the 'Bob Gold's Room Calculator ( http://www.bobgolds.com/Mode/RoomModes.htm)    I've plugged my numbers in there and 3300 looks OK but if I'm honest, I don't know what I'm looking for compared to 3000 or 2700. Is this a reliable tool?

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6 hours ago, mik_m said:

3300. It's just that this seems so high... I'm planning a bulkhead but damn that's a tall roof.

If you "don't like it", then don't do it.   Putting in an aesthetically pleasing roof height is the most important thing.... as long as you don't build a box with sides that are close to exact multiples of each other  (as you will create a more uneven bass response than normal).

 

6 hours ago, mik_m said:

Anyone have any thoughts on the 'Bob Gold's Room Calculator ( http://www.bobgolds.com/Mode/RoomModes.htm)    I've plugged my numbers in there and 3300 looks OK but if I'm honest, I don't know what I'm looking for compared to 3000 or 2700. Is this a reliable tool?

Yes it is (I would assume).   GR is very simple maths .... but it does not matter as much as people believe.    It is not so much that moving ever closer towards the GR is incrementally better, it's that moving towards dimensions which are exact multiple of each other is a problem.

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I've said it before and I'll say it again, I'll take a massive cube over a small "perfect ratio" room any day of the week. This holds especially true with atmos and ceiling heights. The higher the better (within reason). All rooms have acoustic issues, better to have the space to deal with them, then not. In any event, bass will be your concern and if you design the riser properly, you'll have more bass trapping then you can poke a stick at. Problem solved - along with several subs.

 

3300 is pretty much a perfect height. Makes the rest of the house very nice as well.

 

Say you end up with a 500mm high riser, 300mm of bulk heads, thats 2500 (close to "normal" height) when standing on the riser.

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Hey man, good luck

 

looks like you’re at the ‘should I go with what I was thinking’ or go a bit more full on ... it’s like Alice in Wonderland, “how deep does the rabbit hole go?”  It’s fine to not go there if you don’t know any better, once you do know though, it’s hard to ever go back.

 

Not much to add beyond what others have said, but one think I did pick up on was your thinking “get the shell right” (I.e double gyprock) and then “I won’t need to do much in the room” ... but this is confusing the topic of sound proofing (keep external sounds out of the room, and internal sounds within the room) with sound quality (the audio experience inside the room).  This is undoubtedly where an experienced pro can help you get an optimum design.  And it’s better to design on paper before you start building!!

 

Good luck with your journey, it’s lots of fun and very very rewarding 

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3 hours ago, Peter the Greek said:

I've said it before and I'll say it again, I'll take a massive cube over a small "perfect ratio" room any day of the week. This holds especially true with atmos and ceiling heights. The higher the better (within reason). All rooms have acoustic issues, better to have the space to deal with them, then not. In any event, bass will be your concern and if you design the riser properly, you'll have more bass trapping then you can poke a stick at. Problem solved - along with several subs.

 

3300 is pretty much a perfect height. Makes the rest of the house very nice as well.

 

Say you end up with a 500mm high riser, 300mm of bulk heads, thats 2500 (close to "normal" height) when standing on the riser.

yup, I've never known of someone to say "those ceilings are too high", it just gives a more open feel to a room. My room with 2.7m ceilings and a 300m riser feels a bit claustrophobic when standing in the back row, and there is also a projector hanging there. Being an existing home, it was all I had to work with. A higher ceiling will also lessen any heat gain at the seating positions in the room from a projector.

 

@mik_m I'd highly recommend with your budget that you do it right first time round and get it designed AND go a false wall with AT screen, you have the room length to do it easily. You might be able to fit a 140" scope screen but you'd have to have speakers behind the screen to do so. My room is only 20cm narrower than yours and 130 was the best fit for me. Also keep in mind just like a TV, the bigger your screen is the softer the picture becomes. Better to sit a little closer with a smaller screen IMHO

 

On the hardware side of things a mid range JVC projector should be ample, 2x 7ch power amps for atmos, and I'd recommend a processor rather than AVR. Speakers, well that's rather personal, but think Krix AV speakers along with a quality power amp will give you fantastic dynamics and headroom. I found when I added power amps I could hear my system better at lower levels too, the clarity improved at all volumes. Krix are now partnering with Elektra to make a range of power amps to compliment their speakers, as many of us heard at the HiFi Show over the weekend. Elektra amps are used by many members here and represent excellent bang for buck but not exactly cheap either.

Edited by blybo

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