New Flat, New Room, Terrible Accoustics

hello fellas,

i recently moved to a new flat and finished setting up everything in my new “studio room”.
so far the room has not been treated acoustically in any way and i have a terrible resonance at certain frequencies.
i know i have to buy some treatment stuff like bass traps and basotect foam absorber plates (or alike), but the questions are:

  • where exactly do i place it?
  • how much m² do i need?
  • which material is best and how thick does it have to be?

some facts about the room:

  • roomsize is 16,96 m² (3,99m x 4,25m)
  • floor is 100% carpet
  • walls have a thin, slightly structured wallpaper
  • ceiling is totally generic, blank

here are some sketches so you get an impression of how it looks like:

floor plan:

the worst resonance is at around 115-120hz:

this frequency has a reverb decay of about 3-4 seconds on “normal” volume.

i was looking into buying such a set:

do you guys think it would be sufficient? do i need more?
the four basstraps go into the corners (even though one corner will be tricky due to the door) but where do i place the flat foam panels? behind the speakers? opposite to the speakers?

ANY advice is really very welcome.

Yeah, a cubic room is quite a big acoustic problem…
Bass traps in the corners fix the job in most cases, but there might be some more ringing after that treatment.
I think the panels have to go to the reflection points, in this instance, on the rear and behind next to the door. Maybe on the ceiling/ behind the speakers.
Since you mentioned 115 - 120 hz ( which is strange, because small rooms usually have hi-freq resonances) , the plates will have to be thick, probably wooden.

That’s all the advice I can give, sorry, I’m just not a specialist in this field.

you can try out the acoustic foam panels but don’t expect much from them. seeing that your worst resonance is at about 120 Hz, they would have to be pretty thick to work out that problem.

to effectively tame a frequency using this method (acoustic foam) you must use a panel that has a thickness of at least 1/4 of the wavelength of that frequency. so 120 Hz = 2,83 meters wavelength (speed of sound 340m/s / frequency 120 Hz). one quarter of it = 0,7 meters. so your panels would’ve to be 70 cm thick to absorb that frequency - pretty much for a small room like that ;) .

acoustic foam works very well on high and mid frequencies though. i had terrible flutter echoes at around 3 KHz in my room, got me some panels of acoustic foam, echoes gone. worked like a charm.

as for your problem, i think a Helmholtz-Resonator (a so called bass-trap) would work out the best. i can point you to some online-guides to build one, but all in german. maybe it’s better if you search one yourself. i think it’s actually not that hard to build one of these things, just some maths (all formulas can be found online) and a bit of woodwork. i think i’m gonna build one myself at some time. i’m currently looking for a new flat, gonna see how the acoustics will be then.

regarding the placement of a bass trap, it’s best to put it into one corner of the room, because that’s where most of the acoustic energy comes together.

i did a little research now and here’s a good site on Helmholtz-absorbers written in english - might erase some question marks (or generate new ones hehe :wacko: ).

Helmholtz Absorbers

actually it would be good to know if the room is problematic in the bass frequencies only, or in the mids and trebles as well?

if it’s bass only, then you shouldn’t use acoustic foam like basotec, cos they will affect all frequencies above your problem frequency as well. the room might get pretty dull.

if your problematic frequencies are more broad band, just using a Helmholtz-absorber will not solve all the rooms problems (they work very narrow band around their center frequency). in that case a combination of both techniques might give the best result - a Helmholtz-absorber for the bass and thinner plates of acoustic foam for the mids and highs.

thanks for the suggestions.
so you think the foam bass traps from BASF (basotect) with a thickness of 42 cm wouldn’t deal too well with my problem?
im of course a bit worried to blow 235,- EUR for virtually nothing.

as for building the helmholtz-absorber:
i read that “Rockwool Sonorock” material would form a good basis. ( refering to:…725/thread.html )
the problem will of course be, that the door hinders me from placing a absorber in that corner… hope that won’t ruin the efficiency…
besides that, i would be forced to place the absorber ON the table in the two front corners because when i planned the room, i wasn’t considering that the speakers should be placed on stands in front of the table ideally.[b]


i am german. so that link would be very interesting.
but why woodwork? i thought the absorption capabilities of wood wouldn’t be too great. or is it meant to be just as a slim frame / stand for the material?

thanks for your thoughts!

I know someone who had the same problem with the foam stuff blocking the door, but he is pretty much a genius and stuck the foam to a wooden board with hinges (screwed to the wall) so it can be moved aside.

Did you hang curtains? Or do you have a tall bookcase (with books ofcourse)? Helps too :)
Corners are real b*****s when it comes to acoustics. I wish I could help more but I just had my first lessons in acoustics and psychoacoustics :(

no problem man. i’m far from being an expert on this - room acoustic seems to be a whole science of itself - but i had some lessons about it when i was doing my audio degree so know a little bit.

not sure on the 42 cm panels. if my math serves me right, those panels would tame problems down to a frequency of 202 Hz (340m/s / (0,42m x 4 = 1,68m)). anything below is at least questionable. you might get rid of problems in the upper bass, but your real problematic resonance at 120 Hz remains. don’t get me wrong here, getting the panels and placing them in the corners surely does help somewhat, i’m just sceptical it will solve the problem you have. and 235 € is quite much - maybe you could try them out and send them back if they don’t help?

the link you posted makes me smile. although he finally got rid of his problems, he ended up with a room full of acoustic panels. makes me think of a padded cell (Gummizelle). :lol:
and your room is probably to small for that stuff - that technique might work for a recording room but not for a mixing studio.

didn’t think you were german btw so here are the links i mentioned:

Bauplan Helmholtz-Resonator

Bauplan BassTrap + Platten-Resonator

Good background info and calculators

the first link is what i’ll try to build myself at some point as it looks fairly easy.

btw with woodwork i didn’t mean actual wood - just the process of building something on your own instead of buying stuff. you’re absolutely right wood is not a good choice cos it vibrates a lot and has resonances on it’s own. the best thing to use is MDF (Mittel-dichte Faserplatten) cos that doesn’t vibrate at all. Bitumen (Dachpappe) is supposed to be good as well.

oh and here’s a link to a good forum on acoustics in german - folks there can probably help you more than Renoisers can.

Casakustik Forum

hope i could help. good luck with your room! and please give feedback when you found a solution, i’m very interested in that. as i mentioned i’m about to move and might have to workout my room acoustics as well for a reasonable price.

curtains and bookshelves won’t help with bass frequencies though. their wavelenghts are just to big to be affected by these things. generally, as far as i understood room acoustics in the lessons i had, bass frequencies are treated completely different from mids and highs. for mids and highs, methods of choice are either porose absorbers (acoustic foam plates) or diffusors (like the bookshelves you mentioned). bass is usually treated with either Helmholtz-Resonators or Plate-Resonators, that both draft some of the acoustic energy out of the room instead of just diffusing it.

That is absolutely true. I guess read a little to quick.

Don’t get too excited on the absorbers, you need SOME reflection in your room. A “dead” room is very exhausting.

It is important to place absorbers directly behind your speakers and at the sides of your room. Reflectors can be placed on the wall behind you, cylinder shaped ones work the best for that.

Keep in mind you need more absorption than reflection (for every 6 absorption panels, get 2 reflectors).

Hope this helps a bit…

I prepared a little sketch of how I would proceed if I were you.

A Behringer mic (http://www.thomann.d…er_ecm_8000.htm) and the free software “Room EQ Wizard” is all you need to control your treatments. It´s definitily worth the small extra investment.

First of all, in my humble opinion Basotec is crap for low freqs and way too expensive. I´d only use basotec for treating early reflection points and building a ceiling absorber, but not for low freq absorbtion.

Start by placing your monitors away from the wall, your listening position should be at 38% of those 4,25m. I do not recommend to put them on a table, since the table resonates. Use some cheap tripods instead. (e.g. http://www.thomann.d…m_bs500_set.htm). Also - the table in your room seems to be quite big, that´s not exactly going to help with ERs ^^

Then you have to treat the corners behind your monitors (A7 I think?) with something that works deep enough to elimante the boost around 100 - 120hz. I strongly recommend buying some packs of Rockwool Sonorock (Baumarkt!) and put them into the corners, from bottom to top - the deeper the better. 55cm worked well in my case. Please wrap them into foil (Malerfolie, mittlere Stärke) to provide an airtight seal, because you don´t want that stuff flying around in your room :) This also helps to not absorb too much high frequency content - as previously posted, a dull room shouldn´t be the goal. Feel free covering everything with the fabric of your choice to make it look good!

After that I´d treat the back of the room in the same way (which is not possible in your case since there seems to be a door in one of the corners, but nevermind for now) . Later on you might want to add a diffusor behind your back, but I´d take care of the bassfreq absorbtion first.

After installing the basstraps you might want to look into setting up early reflection absorbers on the side walls and on the ceiling. Again, rockwool is just fine and cheaper than basotec.

If there are really deep freqs that trouble you and you can´t get rid of them by using rockwool absorbers you might consider building Helmholtz resonators, but tuning them can be tricky.

Hope that helps a bit.

linus, absolutely great help there. thanks a lot.
yes, i do have the adam a7. moving the table away from the wall is no problem, but i’d have to move it away from the wall for at least 50 cm to be able to place the adams on the stands behind it properly.
and that is unfortunately too much, because when looking at the floor plan, the upper table can move only for about 48 cm to the right until it will collide with the door being open.

in order to avoid resonances, the a7s are standing on 4cm thick foam pads. probably not as perfect as the stands, but i think it’s better than nothing.

i will definately get the rockwool sonorock soon. either at a local “DIY store” or via internet order. on sonorock plate is 1000x625x40 mm (l * w * d). i was planning to get a thickness/depth of 160 mm (4x40mm in a row) with the dimensions 2000 x 625 mm for the front corners and 7x40mm (280mm) for the rear corners.
the basstrap going to the door will have to be moved away back and forth whenever i decide to have a renoise session to avoid conflicting with the door.

the behringer mic has already been order yesterday. i already obtained the roomEQwizard with the suitable calibration file for the mic.

the sketch you made on my floor plan is pretty nice. was planning to get the BT installed the same way ofc. the two ER absorbers you placed puzzle me though. why do you think they should be placed where you sketched them? are you aware of the window when you placed the lower one?

i also heard that such absorbers shouldn’t be placed directly onto the wall but placed like 5 cm in front of them.
do you think that is really important?

i’d rather have a totally dead room than this mess. i can even stand me talking in this room. the reflections and resonances are totally driving me insane.
and besides that, why should a dead room be something not worthwhile? i think the less reflections the more transparency and control you get on your mix, dont you think?
headphones are virtually “dead” as well, when it comes to reflections.

i’m not sure if i wanna get sonorock for the ER plates as well. i think it’ll be a pain in the ass getting them properly into some kind of foil or plastic film (malerfolie). so maybe for that purpose the basotect material will suffice?

thanks again for all the suggestions everyone, you rock!

Oh, my Photoshop skills are somewhat limited - I just wanted to give you an idea. That sketch is not really hyper-accurate ;) You have to find the correct position for the ER and ceiling absorbers via mirror method anyway (google it up!).

I think it is important regarding ER and ceiling absorbers indeed. Imagine the sound to go through the absorber, then hit the wall and go back through them again. I think I used 7cm space for the ceiling absorber, tho.

For ERs I´d say basotec will suffice indeed.

Will have to go through the hassle of measuring and treating my room again soon as I am going to move this may. Yawn.

GIK Acoustics- Monster Bass Traps for that range. Theyre in the UK now. I don’t know what their shipping policy/charges to Germany are. Unfortunately all room problems become budget problems.

i have already bought 20m² of Rockwool Sonorock with a thickness of 95mm to treat the two cornerns in the front (behind the speakers).
Today i am going to build two woodframes for the already cutted material. Dimensions will be like this:

I will update this thread with pics and stuff when i’m done. Currently still waiting for the ordered plastic foil and cloth to cover the wood constructions when ready.
Broadband absorption will be handled by Basotect material with a thickness of 100mm. Also still awaiting the delivery here.

I will update this thread with pics and diagrams of room measurements (RoomEQWizard Pics) when i am done - just in case you guys wanna do something similar in the future.

soooo… i’ve finally finished the basstraps for the two front corners.
i think i will abandon the thought of building them for the rear corners also, as acoustics are already very pleasant right now and it’s a shitload of work to build them in the dimensions i needed to have (see sketch from prev. post)

originally i wanted to build one for each corner with a height of 2470 mm. since it would’ve been impossible to carry them out of the room then, i built two for each corner instead - each with a height of 1240 mm so that only a tiny gap will remain (~3-4 cm) to the ceiling.

the basotect broadband absorbers are already there… next up is building frames for all ten of them in order to mount them on the walls like pictures with simple nails.
that way i won’t have any trouble removing them incase i want to move to another flat some day.

tomorrow i’ll measure the room with room EQ wizard and compare via waterfall diagram the before/after effect. but everyone can easily tell that this is worlds better than before already :)

@keith303: wow, you built them, and actually managed to not make them look ugly!

i understand only half of this stuff, but find it pretty interesting to read. hope you have actually improved your sound with that setup.


i am also quite pleased with the optical result. they’re certainly no beauties which you wanna have in your livingroom, but for a homestudio, the look is totally alright. it also helps to add that special “pro-studio feel”, iykwim ;)
so i just made the new measurements with REW5 and the results reflect my very good subjective impression regarding the acoustics straight away:
(i am just focusing a frequenzy spectrum of 30-300hz, in order to analyze the changes of the room’s low frequency response.)

first measurement, made about 4 weeks ago with no acoustic treatment at all:

there are a lot of standing waves that have a decay time of a around 600ms or higher. most notable and audible are those at 40, 80, and 116,4 hz.

second measurement, made today, with “superchunks” in both vertical front corners.

the most audible standing wave (116,4 hz) was nicely cancelled out by the traps, having a decay time <300 ms down from almost 1.500 ms.
there also is some significant improvement for the 40 hz frequency (decays earlier) but i don’t know what happened to the 80hz room mode, which seems to have a non-linear decay suddenly (dies quickly at first, but than sustains at around 55db for a long time - it also seems to slightly modulate in frequency wtf).

i guess to get completely cancel out the remaining room modes, i’d have to treat the two vertical corners behind me as well, but considering the amount of time i spend for the chunks in front of me, i think i’m done with this ;)

Wow, that is an amazing improvement. Well done!!

i would advice you to look into building your own bass traps,it can be done cheaper than alot of the solutions you can buy,theres some great "tutorials"floating around the interweb about this

EDIT:just saw you have build some bass traps-.—9