Before you buy your next "upgrade"...

Smurfin

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I've always found it odd that the forum is full of posts about kit upgrades, but by comparison there is very little written about room acoustics. In fact, the words "room acoustics" often get interchanged with soundproofing, and of course these are two very different subjects.

It amazes me when I look in the home cinema gallery forum, to see people spending £000s on dedicated rooms, yet in many cases there is no consideration to room acoustics. No matter how "nice" a room looks, the first thing my eyes are drawn to is whether there are acoustic panels fitted and where. I can't help it, and I inwardly groan every time I see nicely painted but completely bare walls.

I posted something similar to this 4 years ago:

Why are there so few threads/discussion around room acoustics?

I've heard many cinema setups, from my own (of which there's been many!), to a number of dedicated rooms of mixed quality, and I've heard treated and untreated rooms, but never have I had the opportunity to hear "before and after" - that is, before treatment, and after treatment, in the space of minutes and with kit I'm very familiar with.

Recently, I bought some GIK acoustic panels from @kbarnes70 ; I bought 7 panels in total, 4 of them measuring 600mm x 1200mm x 100mm thick, and 3 of them the same, but only 50mm thick. These are broadband absorbers, and I planned to position these in my room to cover first and second reflection points.

So what are first and second reflection points?

Firstly, I should say I know practically nothing about room acoustics, and there are plenty of people who can explain these things and offer better advice than me. However, one of the basic principles behind what we actually hear in our rooms is a combination of direct and indirect sound (as I understand it anyway).

Direct sound is the direct output from your speakers.
Indirect sound is a combination of soundwaves which have bounced off various surfaces before they reach your ears.

As an example, take your left front speaker. The soundwaves will emanate from the drivers, and very quickly these will make contact with the nearest wall to the speaker; if there is nothing in the way to absorb this, the sound will bounce off in another direction. If you take a 5.1 system, imagine 3 front speakers, now think of the sound bouncing off the left wall, the right wall, the floor and ceiling, for every single speaker. Put that into a 3D model where a line shows each reflected soundwave, and you will have a very busy drawing with lines all over the place. Then include the surround speakers, go to 7.1, then Atmos....and holy crap, how is that going to sound with everything bouncing around the room?

So what we hear is a combination of direct sound and indirect sound; all of those sound reflections arrive at our ears at different times (but within a split second), and the end result can often be a muddy sound which doesn't image properly; it can be unfocused, dialogue can be difficult to understand, and the whole soundstage becomes less cohesive.

What often happens is that people think "my speakers are poor", or "I need a new AVR as my sound isn't detailed enough". And often people then go and spend a fortune on upgrades, and proclaim a huge improvement because they bought a new receiver. Now, EQ systems aside, I don't believe them. Because what we hear when we watch a movie is as much about the room as it is about the hardware, and so many people seem to forget this!

Kit does come into play of course, although I'd argue speakers can deliver significantly greater improvements than electronics (up to a point), but still...don't deal with the room and you're going to hit that performance ceiling so very quickly. The other factor here is EQ. There are various EQ systems, and in fact I've tried them all over the years (proper high end excepted) - YPAO, MCACC, Audyssey, ARC and finally Dirac, which I'm running in my room currently.

If anyone is wondering the difference the room makes, try this:

Sit in your main listening position, and play a dialogue heavy clip from a movie you know well - set the volume @ a reasonable level (say -10db or -15db).

Now play the clip again, but sit 2' in front of your centre speaker.

In most rooms the centre speaker will sound completely different. It will sound direct; there will likely be an immediacy to the sound, a focus which isn't there when your listening from your normal seating position. What I've always hankered for is that clarity and directness from my sofa, but I've never been able to achieve it. Some of this might come down to the speaker itself, but treating the room can make a HUGE difference in getting you closer to the sound.

So, back to these panels...

With only 7 panels and very little knowledge (those of you who know all about this subject, don't laugh ;) ), I set about positioning them in the room.

I know I should run REW to understand exactly what is going on in my room, but despite having a UMIK-1 I've not got round to dabbling with it yet. Instead, I used the mirror method to find the key reflection points.

Within minutes I identified the reflection points on the left and right walls. On the left hand wall, I moved the mirror until the front left speaker could be seen clearly. 1st panel went here. I carried on moving the mirror until I could see the centre speaker. 2nd panel went here. I then carried on until I could see the reflection of the front right speaker...3rd panel went here.

I repeated this for the right hand wall, and I then had 6 panels positioned.

I then put the mirror on the floor in front of the MLP, to find where the centre speaker reflection point on the floor is (sadly, divorce would be on the cards if I tried anything on the ceiling :laugh: ).

Having put the panels in position, I re-ran Dirac, sat back and watched some movies.

And wow. Just wow.

It felt like I'd upgraded all of my kit. The difference in the soundstage was immediate and striking, especially when playing movies at a loud volume. I watch everything at -10db now, and when the kids are out I'll regularly push it to -5db, and the difference is enormous.

I must admit, previous to this Dirac had the same effect (in that it became easier to watch movies at a louder level), but after treatment it's like someone's grabbed the whole soundstage and clenched a giant fist: everything is tighter, cleaner, and somehow more dynamic.

My dad is 71 and he's about as far from being an audiophile as possible. I put on the first millenium falcon/tie fighter chase scene from A Force Awakens, cranked it to -5db and watched it with the panels; then I took the panels away, switched the Dirac profile back to the previous one, and re-played it.

Within seconds my dad said "It sounds harsh - it's not as nice to listen to".

If you're thinking "well my system doesn't sound harsh" - well, it might not, but until you've heard the effect your room is having on your system, how exactly do you know how much of what you're hearing is the room?

Movie after movie, the effect of room treatment shines through. Dialogue heavy movies are a joy; that directness I mentioned earlier is now there, and there is a precise, clean quality to speech that I was missing before.

The whole soundstage images better. There is no overhang and it's made even the surrounds sound more precise and obvious. I'm running out of audio cliches (this stuff is difficult to describe really), but it's been fantastic to experience such a difference, and the experiment has confirmed what I've always thought.

Of course, there's a huge caveat in this. How many of us have dedicated rooms? Not many, and my dilemna is that I can't go back to having no panels. At the moment I put them away after movie night, and they take up too much space. The wife hates them which also doesn't help, so the compromise for me is to keep the 3 thinner panels (and just treat the first reflection points), and get rid of the 4 thicker ones.

Even if - like me - your room isn't dedicated, it's still worth getting a mirror and finding out where your reflection points are. Heavy curtains, cushions, soft furnishings and rugs can make a huge difference in the right place, and I'll bet that even if you know nothing about acoustics like me, you can make some improvements with a little thought and research.

Room acoustics is science and art and I'm interested to learn more; we would all be served well to consider this before thinking of changing to that new shiny AVR.

Now, where's that dedicated room I've been talking about building (for the last 10 years!) :D
 
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After experimenting, I found this combination of 5 panels to be the most effective: the right hand sofa effectively acts as an absorber for the centre speaker, and whilst I found the sound was improved with a panel lying in the middle of the rug, it's really not practical.

Quite by fluke the collage of photos on the right hand wall is just in the right position, the panels flanking it are in exactly the right place :)

Yes, it doesn't look great, but when it comes to movie time, at least the curtains help to disguise the biggest panels:



You can see just how close the first panels are to the speakers, which is addressing those critical first reflections from the L & R fronts.

 
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This is quite handy if you want to find out where your first reflections are. Not only for the walls but the floor and ceiling too.

Locating areas of first reflections

I'm all for acoustic treatments as they can transform the sound, especially when used in conjunction with room EQ.
 
I often have the conversation about room acoustics and treatments, and our own demo room reflects this, with a carpet fitted, acoustic treatments in the corners, and acoustic panels on the side walls. Another question people often ask is what speaker would we recommend, and again the ideal speaker for one room and one persons taste can often be quite different for that same person in an completely different room. I do also think that the room has to be a consideration for any speaker to reach its potential.

This is an older image now, but the panels etc can be seen here.

demoroom1_540px.jpg
 
There are two problems as I see it.

1) Making these room treatments look natural in living room set ups.

2) Getting permission. (Many of you know what I mean by this!)

Solve 1 and 2 pretty much takes care of itself.

I'm hoping for some canvas prints over some homemade absorbers at first reflection points. Will have to see what I can get away with.
 
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Agreed! GIK do some nice Artpanels...not cheap, but then look at how much people spend on hardware....
 
Agreed! GIK do some nice Artpanels...not cheap, but then look at how much people spend on hardware....

Absolutely, I've spent a small fortune during my refurb (AV equipment and building materials). I'm happy to spend a few quid more on room treatment. The hard part is making it look like it belongs in a living room.
 
The other issue is being able to physically position a panel at the first reflection point; mine is a patio door so I can't fix anything to it on the left side, though I could do the right side if I found a panel that I didn't mind staying up all the time. I'm thinking about having panels that would move forwards with my black side curtains, but not sure if this is practical. It's easy enough to knock something up to try I guess, so that will be another thing to add to my list.

I've put my treatment in the front wall, behind an AT screen (30-60cm deep) and the rest is going in the pelmet to cover the wall/ceiling junction on the two side walls and the back wall. I haven't done the pelmet bits yet, so I'm interested to see how it works out and I will do some measuring as well.

Between the front wall, a large rug and changing our sofas to fabric ones, the room has a kind of 'quiet' feel to it. Even speech sounds different as you walk through from the echoey conservatory or entrance hall. Like Smurfin I've found that the system sounds smoother at high levels, though I can't go back to compare without treatment now. I do know that I seem to be able to listen at louder levels and not find it uncomfortable, so I've made a special point of working out where reference level is so that I know that I'm not going to damage my hearing (further ;) ) by watching at too high a level as it's now so easy to do.

My room treatment cost about £120 (9 packs of Rockwool a mix of 50 and 100mm thickness), plus I've spent another £300 on black Devore velvet for side curtains and room treatment to improve contrast. That's under £500 to give me a major improvement in the sound and feel like I've upgraded to a much more expensive projector. :)
 
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The other issue is being able to physically position a panel at the first reflection point; mine is a patio door so I can't fix anything to it on the left side, though I could do the right side if I found a panel that I didn't mind staying up all the time.

GIK do the 242 panels with stands, so maybe that's a portable option for you?
 
I'm hoping for some canvas prints over some homemade absorbers at first reflection points. Will have to see what I can get away with.
That's a good idea. I've got a large canvas of one of my photographs and that would be perfect for the wall just behind me. I think that is my worse reflection point, the room is pretty good with the good ole clap test.

Edit. I just did the test in Jase's link. Room is pretty good. Window to the right can be solved by drawing the curtains. Reflection to the left is broken up by the furniture. Floor is fine. Rear wall is easily solved which just leaves the wall behind the TV.

All done by luck, nothing by judgement.
 
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GIK do the 242 panels with stands, so maybe that's a portable option for you?

It's finding somewhere to put them when not in use though. I've tried to make everything in the new room a bit more slick and less Heath Robinson having move stuff around, etc. I will try DIY panels to see what difference it makes (just hang a Rockwool slab each side would do), then I can figure out a way to fit them permenantly if I feel it's worth the hassle.
 
My room treatment cost about £120 (9 packs of Rockwool a mix of 50 and 100mm thickness), plus I've spent another £300 on black Devore velvet for side curtains and room treatment to improve contrast. That's under £500 to give me a major improvement in the sound and feel like I've upgraded to a much more expensive projector. :)

I know that this is about sound, however I so agree with the last part.

I used to have quite an epic home cinema, but they ran a road through my house and i was forced to move. The old place had a strange large extension with no windows which turning into a cinema would have added value. My new place is a modern town house and the top/acttic floor is a huge space that is often master bedroom, second living room etc. I realised that converting it to a home cinema the way I did previously wouldn't work, so I want it quickly convertable back. Hence using a load of black fabric and a staple gun. I've been doing things in stages but draping black velvet on the walls made a big difference to picture quality, particularly near the screen. Same with some black suadette on the ceiling and some thick black rugs on the floor.

Couple of hundered for roll ends off eBay and the rugs were about the same from groupon. Massive difference, not much cash and not that much effort to do either!

The rugs certainly help with the sound, don't know if thin fabric will make much difference to the plasterboard walls, but I may also be able to add something undernear or ontop!
 
[emoji769] ;)

Did you move before or after they ran a road through your house?
Haha... Whole load of Lord of the Rings themed panels, Bg808s, riser with cinema seats and lazeboy recliners, aircon, buttkickers, futronix lighting and even the room was acoustically designed as I cut down an L shape to a rectangle and lowered the ceiling. All DIY but it was up there.
Alas CPO and had to move and they bulldozed it all... Kinda killed my passion for a few years!
 
Like others it's the practicality of placing any panels at any 1st reflection points that puts me off. I could put a panel on the left hand wall but thats about it. Right hand goes into a bay window with seats. Ceiling big no no, floor have a rug so not a great deal of options.
Hoping that getting speakers with waveguides will help.


No mention so far of the front wall. Much mileage in putting panels there?
 
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Has anyone tried the primacoustic range?
 
No mention so far of the front wall. Much mileage in putting panels there?

Or the rear wall! Yes to both - I think absorption largely across the front, and diffusion on the rear wall (but it's not quite so clear cut if your MLP is hard up against the rear wall). My experiment didn't extend to there unfortunately. As I say, my room is a living room first and foremost, so anything I put in there has to be removed at the end of the night.

Honestly though, I can compromise and I don't mind the 2 minutes it takes to set them up before a movie...although the room doesn't exactly look nice with them :laugh:

I do have an understanding wife, I must admit...
 
Had a chat with Joe from bluefrogaudio.co.uk regarding my room and he recommended 5" wall panels and ceiling clouds. Also recommended corner bass traps, unfortunately I only have room for one. Some good info on his site.

Education

Definitely going to sort some treatment out for my JBL 3677s in my new room.

Excellent thread Matt!
 
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I forgot about blue frog audio. I remember looking at them a while back.
I've been considering room treatment for a long time now. But the first thing I need to do is get to grips with REW. I have the programme and UMIK-1. I just find myself pressing and clicking on stuff with no real idea what I'm actually doing.
Need to spend some quality time with it I think.
 
But the first thing I need to do is get to grips with REW. I have the programme and UMIK-1. I just find myself pressing and clicking on stuff with no real idea what I'm actually doing.
Need to spend some quality time with it I think.

To be honest I'm in the same boat. I had it for setting up a bfd for sub use, which with a couple of guides worked well.... But room analysis and then knowing what you need and where seems to be less documented. Would be great to be able to go THIS is what I need and then be able to verify that the decision was correct after!
 
I do have the scope for adding some room treatment. I even think it would look ok in the room. Maybe I need to spend some time with someone that really knows REW.
 
Nice post Smurfin. I know nothing on the matter but I'm fully aware of its massive & profound effects on the sound we hear. I've demoed a lot of kit in a Hifi shop near me, and certain kit simply stunning. That same equipment in my 2 homes I've owned, has never matched the impressive sound I hear when demo'ing. And it's all down to the acoustics of the room. I'm sure many have had this experience.
I'm currently working on a 2 channel audio setup from scratch, and it's certainly something I'll be considering later down the line.
Please expect some incoming inquisitive questions :)
 

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