Help me treat my room

[fmessier6]

Good evening!

Sorry for the title but I couldn't come up with a better one.

This year I wanted to learn about room acoustics and treatment, and I wanted to help my room sound a little bit better, with a budget of €1000, which will probably involve 3/4 bass traps and some panels from Thomann.

Given the overall layout, could you be so kind to point me in the right direction and give me a few tips? Ex. My idea was to put Hofa cylinder bass traps in the corners, for starters. But I don't know if I should put something behind the speakers as well (panels). I still have a lot to learn.

This is a concrete room with a wooden ceiling. I'm currenty using this room as a temporary studio since February 2020, but I don't want to over-invest in treatment because at some point this room will be properly transformed (walls, floors.. there is no proper floor at the moment).

Speakers: I'm currently using a pair of Yamaha HS8 but two KH310 are on their way as I speak. A sub will probably follow, but I don't know how my room will react.

 

[Deleted member 23982]

though room to be honest, good thing is the "upper floor" lets basses mostly thorugh, its also a easy spot do add some kind of isolation wool behind some kind of fiber

in my opinion you sit too close to the wall behind you, its good that the speakers are far away from their wall but try to make a compromise to the wall behind you and the wall behind the speakers
your speakers dont look like they are bass-wonders and the problem with the wall behind you is reflecting mids/highs, that the speakers are placed in nearly the middle of the room mostly tackles basses, it should have a very audible effect if you move your desk like 30-50cm to the front (tho i see you kinda need the space (maybe a good way would be to but your desk closer to the wall and put your piano actually behind you))
Speakers half a meter from the wall should be a good starting point, it will add more spacious sound for sure, also a rugg on the wall behind you should have a nice effect, for your piano too i imagine

are their any windows/doors we dont see on the picture?

also first and most effective way to tackle reverb is threating the upper corner of the walls (i did this cheaply with buying "kaltschaum matratzen" and cutting them to triangles (one matratze (sorry for the german words) are 4 triangles, two triangles per corner should have a good effect, just like i did in my room) you can wrap them into some kind of fiber to make it look better

if you dont wanna put basstraps in each corner try to put furniture their, "something" is better than nothing

is the upper floor straight or angled? its kinda hard to see on the picture

 

[fmessier6]

your speakers dont look like they are bass-wonders

are their any windows/doors we dont see on the picture?

Yes, a door I drilled in the available empty space. There was a hole before.

if you dont wanna put basstraps in each corner try to put furniture their, "something" is better than nothing

Thanks for all the suggestions, I really appreciated you taking time to write them. In two corners out of three there are tall Ikea fejkas (fake plants) but I can put bass traps there, no problem!

My buget allows three HOFA cylinder traps, for the three corners. Problem is... they're 100 cm tall, and I assume I'll need to go higher, correct?

 

[abdo123]

Wow that’s bare concrete, ouch!

The good part is you can cover the entire room with absorption and cover the absorption with fabric, this way you can get a recording studio like space and performance (fake walls).

The bad side is that you will lose 20 cm or so of depth against each wall.

 

[fmessier6]

Wow that’s bare concrete, ouch!

I'm afraid of the answer, but could you explain to my why it's bad?

The good part is you can cover the entire room with absorption and cover the absorption with fabric, this way you can get a recording studio like space and performance (fake walls).

Thanks. So no point in drilling the walls and using panels like the one at the left of my picture?

 

[Deleted member 23982]

My buget allows three HOFA cylinder traps, for the three corners. Problem is... they're 100 cm tall, and I assume I'll need to go higher, correct?

most effective to start with are the corners wheir 3 walls meet, second effective are the corners where 2 walls meet and third effect are plain walls to threat (this is specially true on mid/high reverb and bass response, you could also say the whole range but yea...)

so in theory you will already hear a good improvement if you just tackle straight the corners on top or/and bottom, if you wanna go further tackle the whole corner from bottom to top

ah good, i was worried your room is more assymetrical, on the second pic its actually clear that the upper floor is straight
the fuse-case in the corner could be a problem with bass response (because assymetrical corners) but i think its less problematic than the (actual) door, not sure how you closed up the other door, if its with stone it should be no problem

the stack, atleast it looks like it (or does the wall just get "in" because of the fuse-case?) , is hopefully neglidiable, but as always with room treatment, you have to try yourself

I'm afraid of the answer, but could you explain to my why it's bad?

bad for nearly everything, bass response (also reverb i guess) and also mid/high reverb are the best way to describe the issues
if you dont wanna treat each wall with 10-20cm centimeters isolation material (room in room) a rugg is the best you can do on the plain walls (most people say left and right from listening position but also behind and in front of you have a big effect imo specially on 3d spacing of sound)

 

[abdo123]

I'm afraid of the answer, but could you explain to my why it's bad?



Thanks. So no point in drilling the walls and using panels like the one at the left of my picture?

Acoustic foam is dirt cheap (well compared to the average speaker or DAC measured here).

I would definitely get 20 cm deep acoustic foam and just cover the entire space, if it becomes too dark (the opposite of bright) i would start covering the foam with thin planks of wood.

I recommend Basotect and Caruso Iso Bond.

 

[abdo123]

I'm afraid of the answer, but could you explain to my why it's bad?

Acoustically It's like trying to take a selfie in a house of mirrors.

 

[Deleted member 23982]

its probably for the better in such a little room

Also, its good youre using the long wall behind your desk, in theory, if you put your desk close to the wall where the piano sits reverb will bounce off the right/left wall, not to the listening position but actually to the wall behind you, which gives one more bounce and therefore quiter reverb

i can really suggest putting your desk where your piano sits, speakers 50cm from the wall, speaker placement in relation to listening position looks good

Also little things could make a difference, like the mat on your desk, try to get a big one
(also putting speakers higher and angle down could be worth a try)
desks and computer monitors are your enemys unfortunaly (i think its good your monitor is placed in such a way that speakers are behind it)

i maybe also should say this, tho pretty sure it just "really" works on nearly square room, to put your desk in the corner with some distance (and a heavy bass trap behind it in the corner), it made my square room way less problematic and it sounds nearly twice as large now

 

[fmessier6]

Acoustic foam is dirt cheap (well compared to the average speaker or DAC measured here).

I would definitely get 20 cm deep acoustic foam and just cover the entire space, if it becomes too dark (the opposite of bright) i would start covering the foam with thin planks of wood.

I recommend Basotect and Caruso Iso Bond.

Thanks. Should I just put it on the walls like this or does it need some sort of adherence to the wall (glue) ?

Aestethics will go down the drain but if it works I'll be happy to do it.

Also little things could make a difference, like the mat on your desk, try to get a big one

Thanks for your suggestions. I'm using a XXL mousepad. I don't think they make mousepads bigger than this, maybe I should try with two? Is the wood of the desk bad for reflections, that's why you're suggesting this?

its probably for the better in such a little room

Bass is coming, unfortunately for my room, it's only a matter of time. Better work on those traps.

 

[Deleted member 23982]

Thanks. Should I just put it on the walls like this or does it need some sort of adherence to the wall (glue) ?

i never tried full room treatment like this but from what i readed, if you have 10 cm isolation, try to place it 5-10cm away from the wall, it should have "nearly" the effect of 15-20cm isolation then, i also can confirm this with the bass trap i have behind my desk, it gets more effective if its put away a little instead of straight up in the corner

atleast its worth a try as long its not "fixed"

 

[abdo123]

Thanks. Should I just put it on the walls like this or does it need some sort of adherence to the wall (glue) ?

Aestethics will go down the drain but if it works I'll be happy to do it.

View attachment 174843

Yes that's exactly what i'm trying to say, the thicker the foam the more tonally balanced the room will be. 20 cm is a good point as everything above 200Hz will have around the same decay time.

 

[Deleted member 23982]

Thanks for your suggestions. I'm using a XXL mousepad. I don't think they make mousepads bigger than this, maybe I should try with two? Is the wood of the desk bad for reflections, that's why you're suggesting this

yep specially high frequencys because it looks polished, im also not happy with my one i think its 80cm x 40cm (i have a large desk), i just saw recently the LTT store has a really big one i wanted to try
https://www.lttstore.com/products/deskpad actually they have all kinds of sizes, i just looked it up now
i you wanna try the effect, just cover your desk with a blanket, pretty sure you will hear the difference take 2 blankets if its a "light" one, the heavier the material the deeper the frequency is it has an effect on
if you dont hear an effect you should atleast retry it with more room treatment in place

Bass is coming, unfortunately for my room, it's only a matter of time. Better work on those traps.

it will be a hard task i think, but probably doable somehow, you will need heavy bass traps in the corners i imagine, 20cm wall treatment is nearly invisible for deep bass like 20-40hz

also if you go the full room treatment route, dont forget the floor, you could make a "floor on the floor" which is also 10-20 cm i imagine its concrete too right?

 

[alex-z]

Bare concrete is highly reflective, so you will need a fair amount of absorption on all surfaces.

The general goal with a mixing setup is to create a reflection free zone, so that you are listening to the most direct energy possible. Rear wall first because you are sitting very close to it, followed by ceiling and side walls. Front wall can be treated as well, but is lower priority.

Given your budget, building your own panels is highly recommended, otherwise you won't have enough to treat all the major problems. 5.5" mineral wool wrapped in fabric is the most effective solution, as it will work down to 100Hz if a 3-4" air gap exists between the walls and panels.

A subwoofer will always improve your setup if properly integrated, with a high-pass on the speakers and low-pass on the sub. You get to hear more of the low frequency notes, and also less mid-bass distortion. This is because the woofers in your speakers are moving less due to the subwoofer handling bass.

Room modes will crop up and be audible, they already exist, but you don't notice them as much due your HS8 speakers lacking good bass. The KH310A can reach slightly lower, but ideally you would crossover them at 60-80Hz to keep distortion low. It is important you find the ideal subwoofer positioning, with no major dips. Then use EQ after to remove any major peaks. The sweet spot will be relatively narrow with a single sub, but acceptable for mixing work.

 

[Hipper]

I suggest you read a bit on these two sites. They both sell products but the info is good:

https://gikacoustics.co.uk/

http://realtraps.com/

You then have to decide if you want to treat it like a studio or for listening pleasure. I listen for pleasure but I understand studios need to be a bit more accurate, although I like accuracy.

If you are looking for a temporary fix, you can get panels on feet so they can be moved about - or just lean them against a wall. The bigger bass traps just sit in corners so might not be such a problem with fixing.

I tried foam initially but found that mineral wool type products (like GIK and Real Traps sell) are best, certainly for bass traps as they go down deeper in the frequencies. When looking at products you should check how they measure.

The recommended book for all this is Sound Reproduction by Floyd Toole:

Sound Reproduction - Floyd Toole

Take your time so you get it right without wasting money. The general principle is:

1. Reduce ambient noise - noise in or entering your room.
2. Positioning of speakers and listening chair (ears).
3. Room treatment.
4. Subwoofers.
5. DSP/EQ.

A combination of any or ideally all these things should do the job.

What you are aiming for is a smooth, perhaps flat, frequency response, with lowish decay times more or less the same across all the frequencies. My decay times are around 200ms which is a bit low for some but gives me details that I like.

 

[fmessier6]

Given the temporary nature of my stay in the room, the priority would be to take the room from A (zero treatment) to B (something decent).

No big ambitions because budget does not allow them, and at some point in the next five years the room will be re-done from scratch with ten times the budget I have now.

So:

1) I want to keep everything under €1000, if possible
2) Avoid drilling holes or using glue if necessary

What I can do now is put cylinder bass traps in the corners and something behind me, either three thick red panels at listening height as the one in the picture or as per suggestion here, cover the wall with Caruso Iso Bond.

I will try stacking them on top of each other if they allow stacking, like this picture, and put them behind me
(I don't know how rigid they are, I don't want them to fall at some point)

 

[fmessier6]

you can get panels on feet so they can be moved about

I would love to do this, but so far I haven't found a cheap option to mount panel on feet (Europe) unless I go the DIY route.

I would love to have something like this but this one is quite pricey.

EDIT: Nevermind, I found something with feet on gikacoustics that you guys recommended. Looks good too.

 

[Adhoc]

If one is on a tight budget, I wouldn't buy ready made costly absorbers or panels. -After all, the common types are nothing more than glass or rockwool, put in a frame and dressed up with some fabric. (Basotect, a melamine foam from BASF is an exception from those but costly if you want something like 15-25 cm thick and avoid resistive fiber absorbers.) To save money and with little work and tools you can buy some second hand Billy book shelves (IKEA) or other with a closed back. If placed behind you, fill upp the lower and upper part of the shelves with glass or rockwool, in the middle you can have "stuff" which provide some reflections / diffusion. Bass builds up at corners like floor / ceiling and back wall, might be too boomy there. If placed along side walls to kill first order reflections / SBIR, fill up with glass or rockwool in the middle section, lower and top section can have absorbtion or "stuff" to avoid too much absorbtion of mids and treble in the room.

With 28 cm depth, suitable gas flow resisitivity should be about 5-7 kPa.s/m² = fluffy light weight glass wool, for rockwool < than about 30 kg / m³ in density. That thickness would provide good absorbtion (> 80%) from about 120 Hz and upwards. To avoid making the room too "dead" = killing mids and treble while low bass still has too little absorbtion, you can cover the insulation with 0,2 mm thick polyethylene plastic towards the room (same stuff you cover insulation with when you insulate house walls). You then staple some nice fabric over it or make an insertable frame with fabric. I would probably replace the flimsy back of the Billys with plywood or MDF. If you measure the room and find out your troublesome mode frequencies, you can "transform" the Billys to tuned helmholtz absorbers if you have plywood sheets both at front and back, with one of the plywood sheets perforated to tune to a specific frequency range.

I would personally leave about one meter free space towards the rear wall where bass build up. Also, I would place the speakers as close as possible to the front wall. The closer, the higher SBIR frequency = easier to absorb with thinner absorbers. 1 meter away from front wall and you will have a null around 85 Hz = impossible to absorb with a thin absorber. A speaker baffle 25 cm or so from front wall will give a null at around 700 Hz = much easier to fix that destructive reflection. (This depends partly on type of speakers of course, you get some free gain in the bass with near wall placement, can be good or bad.)

Link if you would like to got the cheaper DIY way: http://www.acousticmodelling.com The simulations for the bass traps / absorbers are based on a large area being treated. Only 1 or 2 shelves (or a few bought panels) will not cover much of your room surfaces, will not make that much of a difference. Your biggest problem will be treating the bass while at the same time not absorb too much of mids and treble.

A ps: Those absorbers you showed pictures of are nice looking but totally worthless if you wish to treat bass frequencies in a concrete / stone wall room. They have good absorbtion from (I guess) about 4-500 Hz and upwards.

 

[fmessier6]

If one is on a tight budget, I wouldn't buy ready made costly absorbers or panels. -After all, the common types are nothing more than glass or rockwool, put in a frame and dressed up with some fabric. (Basotect, a melamine foam from BASF is an exception from those but costly if you want something like 15-25 cm thick and avoid resistive fiber absorbers.) To save money and with little work and tools you can buy some second hand Billy book shelves (IKEA) or other with a closed back. If placed behind you, fill upp the lower and upper part of the shelves with glass or rockwool, in the middle you can have "stuff" which provide some reflections / diffusion. Bass builds up at corners like floor / ceiling and back wall, might be too boomy there. If placed along side walls to kill first order reflections / SBIR, fill up with glass or rockwool in the middle section, lower and top section can have absorbtion or "stuff" to avoid too much absorbtion of mids and treble in the room.

With 28 cm depth, suitable gas flow resisitivity should be about 5-7 kPa.s/m² = fluffy light weight glass wool, for rockwool < than about 30 kg / m³ in density. That thickness would provide good absorbtion (> 80%) from about 120 Hz and upwards. To avoid making the room too "dead" = killing mids and treble while low bass still has too little absorbtion, you can cover the insulation with 0,2 mm thick polyethylene plastic towards the room (same stuff you cover insulation with when you insulate house walls). You then staple some nice fabric over it or make an insertable frame with fabric. I would probably replace the flimsy back of the Billys with plywood or MDF. If you measure the room and find out your troublesome mode frequencies, you can "transform" the Billys to tuned helmholtz absorbers if you have plywood sheets both at front and back, with one of the plywood sheets perforated to tune to a specific frequency range.

I would personally leave about one meter free space towards the rear wall where bass build up. Also, I would place the speakers as close as possible to the front wall. The closer, the higher SBIR frequency = easier to absorb with thinner absorbers. 1 meter away from front wall and you will have a null around 85 Hz = impossible to absorb with a thin absorber. A speaker baffle 25 cm or so from front wall will give a null at around 700 Hz = much easier to fix that destructive reflection. (This depends partly on type of speakers of course, you get some free gain in the bass with near wall placement, can be good or bad.)

Link if you would like to got the cheaper DIY way: http://www.acousticmodelling.com The simulations for the bass traps / absorbers are based on a large area being treated. Only 1 or 2 shelves (or a few bought panels) will not cover much of your room surfaces, will not make that much of a difference. Your biggest problem will be treating the bass while at the same time not absorb too much of mids and treble.

Thank you so much, this is unvaluable information. I'm saving everything on a word document and learning as much as I can.

Right now yes, the budget is tight but I would rather buy something pre-made since I have very little time and I pretty much suck at DIY.

A ps: Those absorbers you showed pictures of are nice looking but totally worthless if you wish to treat bass frequencies in a concrete / stone wall room. They have good absorbtion from (I guess) about 4-500 Hz and upwards.

They would be paired with bass traps in the three corners, I was thinking a couple of these per corner stacked on top of each other, total six. In another thread an user showed concern for the fact that these wouldn't be able to absorb much given their small diameter.
The HOFA alternative has a diameter of 43 cm, and costs almost twice as much.

 

[Adhoc]

Those circular absorbers may be called bass traps in the advertisement but are they ...? I guess my Italian is about as good as your Swedish, but I couldn't find any specification / detailed test report from a reputable laboratory for them. If one reads acoustic books (like Cox' and D'Antonios' book Acoustic Absorbers and Diffusers) it is mentioned suitable thickness for a resistive absorber starts to have a significance around 1/10 to 1/7 of the wavelength to be treated. Starts to have is not the same as being very effective .... The diameter (max thickness) is 30 cm and 60 Hz has wave length of 5,7 m. How wide is your room ? 60 Hz played out from the speakers at front wall will be covering the total width and height of your back wall. So, how large a percentage of the back wall will be covered with 2 of those cylinders (?). Not much, so one shouldn't expect much of a result either. Same thing with the Hofa, it is better with Ø 43 cm yes, but still small compared with bass frequency wave lengths. Effective absorbtion needs thickness and area coverage in relation to the wave length of interest.

It seems you could be paying for some nice visual appearance but lacking real acoustical effectiveness in your stone room. A very good book to study would be Acoustics in Small Rooms by Mendel Kleiner and Jiri Tichy, https://www.routledge.com/Acoustics-of-Small-Rooms/Kleiner-Tichy/p/book/9781138072831 It costs a bunch but can also downloaded as a pdf for free if you have a spatial moral conscience (= a thief ). Beware of "suspicious web pages" though in that case.