Room Treatment

[adamg67]

Interested reading the home studio porn thread that lots of people have sound treatment in their rooms at home. Obvious question, how do you figure out what you need and where you need it?

[SubsonicSimpleton]

There is lots of information on room design and treatment here.

http://forum.studiotips.com/index.php

This article is a good place to start

http://forum.studiotips.com/viewtopic.php?f=5&t=3314

[Skol303]

I can't recommend the Gearslutz forum enough for this kind of thing...

https://www.gearslutz.com/board/studio-building-acoustics/

... lots of pro audio folk on there who are happy to help.

Other than that, there are basically two ways of approaching this:

1) The easy way, which is to assume that your room will need bass traps in every corner, side panels next to where your desk is and a 'ceiling cloud' panel above it. Pretty much 99% of home studios will need that exact treatment.

2) The more involved way, which is to buy yourself a calibrated measurement mic, download a free copy of [url="https://www.roomeqwizard.com"]Room EQ Wizard software[/url], learn how to use it (no mean feat - I've dabbled!) and get yourself some accurate room measurements to inform your choices for acoustic treatment.

Or... if you're able to spend some money, there are a number of companies who can do all this for you. The people at [url="http://gikacoustics.co.uk"]GIK Acoustics[/url] are arguably the market leaders with offices in the US and UK. Very helpful by all accounts. I personally have experience of using [url="http://www.bluefrogaudio.co.uk"]Blue Frog Audio[/url] (small independent company), who were just great and spent a lot of time working out what treatment I needed, using Google Sketchup to illustrate their ideas.

But ultimately... acoustic treatment is a HUGE topic that gets very scientific very quickly. There's lots of basic advise on Gearslutz and elsewhere online (pretty much summarised by my point 1 above), but of course each solution is ultimately specific to the room itself - so if you want a detailed answer, you need to measure/provide the detail yourself or ask for help from a professional. Which sadly isn't me

[roman_sub]

I'd start with thinking about these 3 areas:

1) basstraps - corners and where wall meets ceiling behind speakers

2) absorbers - to kill first order reflections from speakers - i.e. ceiling above, and to the sides (think of it as a mirror)

3) some sort of diffuser behind you - bookshelf with randomly stacked books is acceptable as a real world compromise....


other than that, aim for symmetry between walls, and ideally sitting at around the 38% mark of the room.... don't be afraid to experiment with speaker positioning too, especially if they are rear-ported. sub-woofer set up is a whole new area too....

good luck!

[WinterMute]

There's also [url="http://www.eqacoustics.com"]http://www.eqacoustics.com[/url] who do very good home studio studio kits and will help with advice.

I used Fuzzmeasure to get the basic plot of rooms to tell me where the problems are then apply bass traps to the nodal points, (corners basically) and some absorbers at the Early Reflection point, this will help tame most problems to a degree.

Fibre cored units are much better than foam, which isn't as effective as some people would have you believe, but will help some.

Diffusion isn't much use in a small room, but is very good in larger spaces with taming reverb and echo problems.

[Skol303]

[quote name='WinterMute' timestamp='1506262631' post='3377393']
Fibre cored units are much better than foam, which isn't as effective as some people would have you believe, but will help some.
[/quote]

Absolutely this. Foam is next to useless for taming bass, which accounts for 99% of problems in 99% of home studios [i](*Department of Made Up Statistics, 2017). [/i]It mostly just dampens the high frequencies, which can leave the room sounding 'off'.

Bass trapping is all about density and volume of 'stuff' and the more the better. Most manufacturers seem to use ECOSE (a type of Rockwool). If you have the time and patience, you can manufacture bass traps yourself fairly easily and cheaply (says someone who has never done this himself...). Lots of tutorials online for how to do so.

[quote name='WinterMute' timestamp='1506262631' post='3377393']
I used Fuzzmeasure to get the basic plot of rooms to tell me where the problems are
[/quote]

Never heard of FuzzMeasure before. I'm going to investigate...!

Edited September 25, 2017 by Skol303

[WinterMute]

[quote name='Skol303' timestamp='1506349650' post='3378092']
Absolutely this. Foam is next to useless for taming bass, which accounts for 99% of problems in 99% of home studios [i](*Department of Made Up Statistics, 2017). [/i]It mostly just dampens the high frequencies, which can leave the room sounding 'off'.

Bass trapping is all about density and volume of 'stuff' and the more the better. Most manufacturers seem to use ECOSE (a type of Rockwool). If you have the time and patience, you can manufacture bass traps yourself fairly easily and cheaply (says someone who has never done this himself...). Lots of tutorials online for how to do so.



Never heard of FuzzMeasure before. I'm going to investigate...!
[/quote]

It's a great little room measurement tool, but it relies on the quality of the mic and speakers, best used with a good Omni and whatever monitors you intend to use in the room...!

I did think about building the bass traps myself, but I'm just not that good at DIY and EQ do some really good packs.

If you've got more money that sense, take a look at these little boxes of voodoo, they are unbelievably good. [url="http://www.psiaudio.com/en/our-products/avaa-c20-active-bass-trap/"]http://www.psiaudio.com/en/our-products/avaa-c20-active-bass-trap/[/url]

[adamg67]

Thinking about FuzzMeasrure (which is mac only, so no good for me) I have a vague memory of seeing a video someone "shooting a room" using a mic, and I guess it must have been a frequency graph? So you play stuff, poke your mic into different bits of the room and see if the frequencies coming back are the same as in the original. Does that sound sensible? It would work for bass traps maybe.

[WinterMute]

[quote name='adamg67' timestamp='1506429156' post='3378647']
Thinking about FuzzMeasrure (which is mac only, so no good for me) I have a vague memory of seeing a video someone "shooting a room" using a mic, and I guess it must have been a frequency graph? So you play stuff, poke your mic into different bits of the room and see if the frequencies coming back are the same as in the original. Does that sound sensible? It would work for bass traps maybe.
[/quote]

Sort of, you put the mic in different places, the listening spot, the back of the room, a few others and you play a combination of sweep tones, blips and white or pink noise (not all at the same time...) then the software shows you a waterfall graph of the frequency response, another of the RT. You can see where the frequencies are exaggerated and/or missing and you can plan accordingly.

Some 5.1 receivers do the same thing for living rooms and surround systems with a bit more automation and EQ.

Here's the waterfall plot of my room in the listening position and the back wall, you can see the difference in the bass response.

[attachment=254468:Listen pos waterfall.jpg]
[attachment=254469:Rear wall C waterfall.jpg]

That's why you bass trap the back wall and the corners. Evened it out a bit with the traps, still too bassy on the back wall, but you don't listen critically in that position and the response only needs to be even at the listening position for such a small room.

[adamg67]

[quote name='WinterMute' timestamp='1506545001' post='3379509']
That's why you bass trap the back wall and the corners. Evened it out a bit with the traps, still too bassy on the back wall, but you don't listen critically in that position and the response only needs to be even at the listening position for such a small room.
[/quote]

I was thinking exactly that when I was in the room the other day, it only really matters how it sounds where I sit. I'm on the "long" wall but still close to the wall behind me, the room's only 2 x 2.5m anyway so it's hard to get away from it. We're looking to move next year, so this might be something to look at after that

[tedmanzie]

[quote name='Skol303' timestamp='1505741541' post='3373909']
I can't recommend the Gearslutz forum enough for this kind of thing...

[url="https://www.gearslutz.com/board/studio-building-acoustics/"]https://www.gearslut...ding-acoustics/[/url]

... lots of pro audio folk on there who are happy to help.

Other than that, there are basically two ways of approaching this:

1) The easy way, which is to assume that your room will need bass traps in every corner, side panels next to where your desk is and a 'ceiling cloud' panel above it. Pretty much 99% of home studios will need that exact treatment.

[/quote]

Bit late to this thread, but I agree with this, and would also add 'difussion' which is anything from shelves full of books to specialist panels. I built my own bass traps using Knauf ECOSE , I think it was the 45 weight (i'd have to check) and put them in all coreners, 600mm depth. The side panels and cloud, from thinner panels, also make a difference - you can buy those in many places, although I also made mine.

Once you have put some essential treatment in I would [i]definitely[/i] recommend Sonarworks - it's a software room correction. You get a calibrated mic, it walks you through the measurement, and it creates a custom EQ curve - essentially an inverse of your room, boosting the dropouts and cutting the peaks. For £250 ish quid it is amazing - I have a lot of room treatment and expensive monitors and Sonarworks makes the sound MUCH better. One of the things it does which you can't do any other way is send a different eq to left & right speakers (if it needs to) - in my room, which has a problem with being asymetrical, I now get a solid central image which just sounds hazy when Sonarworks is disabled. Highly recommended!

[BigRedX]

Remember that something like Sonarworks should only be used after you have done as much as you can with traps and diffusers. Plus using an EQ curve to correct room problems only works for the position at which you measure your room (i.e. where the mic is) and any change to the room including having other people in it will change the effectiveness of that correction.

[tedmanzie]

[quote name='BigRedX' timestamp='1509031017' post='3396180']
Remember that something like Sonarworks should only be used after you have done as much as you can with traps and diffusers. Plus using an EQ curve to correct room problems only works for the position at which you measure your room (i.e. where the mic is) and any change to the room including having other people in it will change the effectiveness of that correction.
[/quote]

I totally agree re. doing treatment first.
Re. Sonarworks the 'sweet spot' is quite wide - it measures from about 30 points in an area about 4 feet wide and three feet deep, and presumably averages those. Bear in mind that that you mix in one position anyway. I was quite sceptical, but I have to say I am very impressed.

[Skol303]

[quote name='tedmanzie' timestamp='1509034257' post='3396214']
I was quite sceptical, but I have to say I am very impressed.[/quote]

Ditto. My room is treated as far as it can be whilst still remaining accessible to other members of our family, rather than being my own private padded cell.

Sonarworks make a very noticeable difference and my mixes have translated much better since I started using it, especially when it comes to mixing the low end. Highly recommended.

[adamg67]

Still not sure whether to go for this on the box room if we're likely to move, but if I do I'll definitely look at Sonarworks

[roman_sub]

Sonarworks does look pretty good in concept admittedly. However, don't be convinced you can't mix without it: once the biggest room problems have been addressed, it is still very much possible to make great mixes even in sub-optimal spaces.

The key is lots and lots of referencing and getting your ears used to how music you know sounds in your particular room; then mix with that in mind. Did I say lots of referencing to commercially released tracks? :-)

Misjudging low end is definitely all too easy - not helped by often-utterly-excessive amounts of super lows contained in drum samples or stock synth patches... I suspect this is done to sell software / hardware, not help you mix well! But that's another rant...

Edited November 2, 2017 by roman_sub

[Skol303]

[quote name='roman_sub' timestamp='1509664912' post='3400782']
Sonarworks does look pretty good in concept admittedly. However, don't be convinced you can't mix without it
[/quote]

Absolutely.

I'd go as far as to say that you don't even need a good room. I mixed for years on headphones and still do 80% of my mixing on Apple earbuds and a crappy set of cans we have kicking around for general use at home. The remaining 20% or whatever is what my room, Sonarworks, outboard, etc, helps me to attain. But a lot of that could be achieved on headphones with sufficient referencing and patience.

For me, having a treated room (albeit a very amateur DIY setup!) is more about convenience and speeding up workflow than it is about attaining better quality output.

[Skol303]

On 24/09/2017 at 15:17, WinterMute said:

I used Fuzzmeasure to get the basic plot of rooms to tell me where the problems are then apply bass traps to the nodal points, (corners basically) and some absorbers at the Early Reflection point, this will help tame most problems to a degree.

A quick follow-up to this...

I've recently bought Fuzzmeasure (love it, very easy to use and much more intuitive than REW) and have taken some initial measurements of my room.

Not too shabby... not especially great... which is pretty much as I'd expect from a small DIY home studio  I'm quite happy with the flat response apart from the chasm of a dip between 60-100Hz, which is almost certainly caused by SBIR cancellation (nulls caused by speaker-boundary interference; a problem that all rooms suffer from and especially between these frequencies). I don't think any amount of additional bass trapping is going to fix that; so I'm now considering getting a subwoofer to help even out the low end and fill some of the 60-100Hz null.

I'll report back here with the results when the time comes.

In the meantime, I highly recommend acoustic measurement to anyone using studio monitors at home. Without it you have no real idea of what you're hearing and will always be mixing 'in the dark', especially when it comes to bass frequencies. I picked up a cheap omnidirectional mic for £50 and initially used the free REW software to take measurements. Even if your room has significant peaks and nulls - and it almost certainly will! - it's always best to know about them, so you can take them into account during your mix decisions.

Anyway, here's what my room 'sounds like' at the moment:

1) Frequency response showing the big dip around 60-100Hz, caused by sound bouncing off walls/surfaces and cancelling out. The rest of the room is thankfully fairly flat and even.

2) Low frequency waterfall graph showing the time sound takes to diminsh at different frequencies (a much better picture of how the room 'sounds' than a frequency response graph alone).

3) Envelope time curve shows the energy of the test signal plotted over time. Very useful for checking the early reflection points (surfaces that the sound is bouncing off), seen as the spikes in the graph.

Edited January 11, 2018 by Skol303

[Skol303]

Quick update...

There's been various talk of room treatment in the 'Rec forum recently (perhaps because we're all stuck indoors due to the crappy weather), so I thought I'd update this thread with my own recent experiences.

We're lucky to have a dedicated music room at home (a converted garage), which already has a good amount of acoustic treatment - but was still suffering from a sizeable null (dip) in the low end around 60-70Hz, caused by a combination of a room mode at this frequency and other surface reflections typical of rooms this size. Unless you live in a mansion, your own room will suffer from this exact same problem (albeit at a different frequency), I guarantee it! So how to go about solving this...?

Firstly, I moved my listening/mixing position towards the front wall of the room and pushed my speakers as close to the wall as possible. This helped to reduce the depth of low frequency dip by reducing the speaker-boundary interference - explanation of that here. This is a great 'free' acoustics trick that applies to any room.

Secondly, I've been busy making bass traps. Lots of bass traps! Sufficient that the room is now quite literally a padded cell (my wife remarked: "My god, you've actually created a womb, haven't you!?"). The intention here was to slam the low frequency energy around 60-70Hz and in doing so, hopefully reduce the magnitude of the frequency dip (by reducing the energy of the phase cancellation).

Here are some Sketchup images showing what the room now looks like (Sketchup is great for planning acoustic treatment). In a small room like this - and when dealing with low frequencies below 100Hz - it's a case of bass trapping the bejesus out of the back wall! But in my case the back wall had no space left for acoustic treatment - so my solution was to create two portable bass traps on stands, which could be placed behind my listening position when mixing (effectively adding about a foot of mineral wool of the back wall).

Plan view of the room: panels in red are portable on stands.

Side view: wall panels removed to show listening position.

Front wall view of listening position. The darker coloured panels at the bottom of the window space are diffusors.

Back wall: bass traps on just about every available space!

[Skol303]

So what difference did this make to the sound?

Well, quite a lot... as I'd hoped! The big dip in the low end around 60-70Hz was considerably reduced (by 12db) so that it's now around -5db of the 'ideal' at this frequency - and I can live quite happily with that

On the flipside, moving my listening position forwards has created a bunch of new phase cancellations between 700-1000Hz, which I'll gave to fix by other means (but thankfully nowhere near as difficult as treating the low end).

So the frequency response in my room is still far from flat - and it never will be - but it's now flat enough for me to trust that what I hear at the listening spot is a fair representation of what's happening inside my DAW software; and that the sound isn't being too adversely coloured by the room itself. Here's how the measurements now look...

Frequency response from 20-20K Hz. Still some peaks and dips as you'd expect, but the 'Grand Canyon' around 60-70Hz is mostly gone and the overall trajectory is reasonably flat (NB: by comparison, the very best pro mix rooms have a frequency response within +/-5db across the spectrum).

More detailed plot, showing the 'before' measurement (in red) and the 'after' measurement (in blue). Notice how moving the mix position forwards and adding bass traps has greatly reduced the big dip around 60-Hz... but created new problems between 700-1000Hz! Such is room acoustics, that making a change in one area always affects others.

Lastly, a shot of the low end in detail (again red shows before and blue after).

[Skol303]

Was it worth it? Well I can now hear the frequencies between 60-70Hz, rather than them being almost non-existent, so yes I'd say it was worth the toil of making all those bass traps... but that's me. I make a lot of bass-heavy music and so anything that improves the low end is going to translate (hopefully!) into better mixes. The proof of that pudding will be in the eating

In the meantime, I just need to find a way of stopping my two young boys from using the bass traps as karate practice pads whenever they come in the room. Hmmm.

PS: it's taken a heck-of-alot of reading/researching for me to get my head around home acoustic treatment, but it's been 'fun' (I get that my idea of fun is perhaps unconventional). If anyone else here is scratching their head over this stuff, then ask questions here and I'll try to answer as best I can and save you some time.

Edited February 17, 2018 by Skol303

[Dad3353]

What bait do you use for your bass traps..? I tried click-bait for a while, but it didn't trap bass, only Spam. The tone I'm hearing in my headset is much better now, though. Now, if only I could find something to reduce the constant chirruping in my ears and those persistent angry steam whistles, I'd be able to mix with the best of 'em. 

Next project..? Oak panelling for the Main Library, and draperies for the West Wing. I may consider plasterboard for the domestics' quarters (but may not...). 

[Skol303]

1 hour ago, Dad3353 said:

Next project..? Oak panelling for the Main Library, and draperies for the West Wing.

Nope. Leather upholstery and new alligator pits for the dungeon.

Just as soon as I sort out the acoustics down there...  

[Skol303]

Dear ‘Rec Forum folk, my room treatment is now finally finished. Thank ****!

Long, waffly post ahoy! And to be honest it’s probably of no interest or relevance to many of you… so don’t go thinking that you need to do any of what I’m describing below. None of this is crucial for enjoying making music at home and producing great-sounding mixes. I previously had no room myself and worked on a laptop with headphones. So if you’re new to this forum, this isn’t the place to start. But if you do already have a small studio at home and are looking to squeeze every last decibel of acoustics out of it, then there may be a few nuggets of info here that can help.

DISCLAIMER: I am not an acoustician! Far from it. I'm just a DIY acoustics nerd who's pieced together knowledge from forums (notably www.gearslutz.com); books (Rod Gervais' 'Home Recording Studio' is recommended); and by chatting with real acousticians online, who are mostly a very friendly and helpful bunch. So don't take any of my advice as Gospel... but hopefully I've managed to explain some of the basic principles in ways that other newbies can understand. If not, feel free to ask questions and I'll do my best to help.

As a quick recap, here’s where I started out…

The graph below is the frequency response of my room before I set about trying to make improvements (acoustic measurements taken using FuzzMeasure). Bear in mind that the room already had a fair amount of acoustic treatment at this stage: front/rear corner bass traps; side and ceiling broadband panels; rear wall treatment. All of the basics covered.

Looks a bit wiggly, innit? But looks can be deceiving… and even with a response as uneven as this, the room was still good to work in; I just had to spend more time referencing my mixes to ensure they translated outside of the room. So if you measure your own room and get a reading like the one above, don’t despair. It’s perfectly normal for a home studio (great article here for reference) and there are lots of ways you can improve it, as we’ll get on to below.

Some points to note at this stage:

• The big ol’ Grand Canyon of a dip around 60-70Hz… all -30dB of it! That’s caused by a double-whammy of having a room mode around 65Hz (caused by the dimensions the room) and a boundary reflection (caused by the distance from my speakers to the front wall). Every home studio will have a dip of this kind somewhere between 50-100Hz or so. You can test your own room by playing a low frequency sweep (sine wave) and listening to the point at which the sound seems to disappear. Congratulations, you’ve found your low frequency null! Also known as low end “suck out”. It’s one of the trickier problems to fix in a small room.
• Note also the jaggedy response in the higher frequencies. In my case, that’s mostly caused by reflections off my desk… I like a big desk and I cannot lie. Smaller desks = fewer reflections but more ‘floor bounce’ (peaks and dips caused by low frequencies rebounding off the floor). Acoustics is full of compromises! I stuck with the large desk cos’ I like having lots of stuff within easy reach. But generally speaking, smaller desks are probably the wiser choice.

Edited May 5, 2018 by Skol303

[Skol303]

So how did I go about improving the acoustics of this room?

1. I added more acoustic treatment and specifically bass traps. As a rule of thumb, you want to cover ~20% of the room surface area (minus the floor) with acoustic treatment in order to achieve a significant difference. This often makes it difficult to sufficiently treat rooms that aren’t dedicated as studios, because it’s difficult to fit that amount of acoustic treatment into a lounge, bedroom, etc, around other furniture. Well, not without really annoying anyone you may be living with. My room is now somewhere around 37% treated and it feels like a padded cell. But just do what you can. And forget worrying about creating a “dead room” with too much acoustic treatment (more on that below). If your room is small, you can never have too much treatment if you want any chance of controlling the low end. So go nuts with it.
2. I moved my speakers and desk towards the front wall, as close as possible. Unless you have gigantic rear-ported woofers, forget whatever advice is printed in your speaker manual and get those cabinets within millimeters of the wall. Same applies to the 38% rule for optimum listening position - forget it. In most small spaces, the 38% rule will place you close to the middle of the room, where you’ll find one of the strongest room modes (frequency dips) there is. Move forwards away from it. Moving my speakers and listening position had the biggest impact on that gnarly 60-70Hz null, lessening it by around +12 dB, and it didn’t cost me a penny.
3. I angled my desk forwards by around 5 degrees using a split fencepost as wooden ‘shims’. This noticeably reduced the comb filtering caused by high frequencies reflecting off my desk. Another cheap yet effective solution.
4. I installed a subwoofer. As you’d expect, the sub added a lot of low frequency energy that helped to 1) fill in the null at 60-70Hz by a further +5 dB and 2) smooth out the low end more generally, giving me a flat frequency response down to 30Hz (with digital EQ applied), where previously the response was very weak. Bass in the place. A word of caution: I would strongly advise against using a sub in a small room if you’re not also using room EQ software (or some other form of DSP) to shape the resulting frequency curve. You’ll just end up with loads of boomy low end, without any of the benefits. Best options for room EQ software that I’ve tried are Sonarworks and Dirac Live. Room EQ Wizard (REW) software, which is free, can also be used to calculate a corrective frequency curve. Well worth trying.
5. Lastly, as mentioned above, I used room correction software (digital EQ) for finishing touches. This included: 1) leveling out the low end boost caused by the sub and close proximity of my monitors to the wall; 2) setting a target curve for the frequency response so that it’s not actually ‘flat’ (which would make the high frequencies very harsh) but instead more natural-sounding. For this I used the classic Bruel & Kjaer frequency curve, which has stood the test of time since the 1970s and is used by many studios today (Sennheiser HD-650 headphones, a popular choice amongst mix engineers, also follow this curve very closely). The idea is that the curve approximates the majority of “typical listening environments”, so that if your mixes sound good using the B&K curve then they’re more likely to translate well to other rooms/ environments.  It’s loosely characterised by a downward slope of around 6dB from low to high end. If you have room correction software, you can try it for yourself using the following settings:

0dB 30Hz
+3dB 100Hz
0dB 2K
-3dB 10K
-6dB 15K

Edited May 5, 2018 by Skol303