Low frequences problem, need help!

There are pictures from EQ Wizard, measuarements of my listening room. I feel that something is wrong from 20 to 120 Hz. Maybe I am wrong. Sometimes for example bass guitar is not define enough, sound like it play from cave. Is there anybody who can help me with this? Thanks in advance PS sorry about my english writting

duki - can you give us some pictures of your control room and it's measurements..

Hello John thanks for your response here are some pictures from sketch up with dimensons. The red color is porose absorbers,the green color are Helm holtz resonatores end perforated absorbers.Between speakers is porose absorber 20cm rockwool with airgap 10cm all together 30cm.In the front corner are Helm Holtz four of them,two are for 45hz (1000lit) and another two are for 68 hz allso 1000 litars.Then coming perforated one (D8mmRaster16MM)73cm width for 100hz to up. Then Helmholtz for 90hz 100 cm width and the last is allso perforated (D8mmRaster16MM) 50cm width.On the side walls behiden listenihn position there are two porose absorbers(70x150cm) rockwool 10cm tick and allso two perforated (D8mmRaster16MM) 50cm width.On the back wall in the corners there are Helmholtz for 30Hz all together in both corners are 1050 litars.In the midle of the back wall is one porose absorber 100cm X 250cm X 30cm full of rockwool 100kg/m3.The celing is coverd with 20cm rockwool 50kg/m3.The small room behind the listening room is kitchen.

Duki - here are your room modes:

Duki - here are your room modes: http://johnlsayers.com/Recmanual/Titles/Fullindex2.htm - Room Modes note the problem around 42 - 44, 86 - 89hz . You need to move the low frequency waves around and some pissy foam structures on the walls won't do it. get my gist??

Hi John i do not understand this. You need to move the low frequency waves around?? You suggest to make more absorbers for 42 -44 hz and 86-89hz ?About room modes you mean that the 1st harmonic 44 hz of the 7.4m is some how conected with the fundamental 43 hz of the 3.8m and the 3rd harmonic 89 hz with 1st harmonic of 86hz?So i need more absorbers??

No - I'm suggesting you put some angles into your room instead of the square shape it has.

Ok John I will make some drawings in sketchup so you can coment if it is posible?Any suggestion will be great. Thanks.

Hi John this is setup I have tryed but no success.Do you have any idea for me?

John (HELP!!)- I tryed to angled front walls like on the picture it is more then 6 degree each ,also beck wall corners but no result.

could you give us some pictures of what those green things are?

Hi John In the corners behind the speakers are Helm Holtz resonators working on 45 and 68 hz others are perforated absorbers (it is on the link) working like helm holtz resonator.The one in the midle is Helm Holtz resonator working on 90 hz . . http://www.trikustik.at/fileadmin/media ... _R8D6V.pdf

This is my ceiling,20cm rockwool 50kg/m3 covered with fabric.

so the only mid - high frequency absorption you have is on the ceiling. You have a glass door on your rear wall and nothing on your front wall. I'm very suspicious of those helmholtz units working in the frequencies you've stated - I don't expect them to work below 100hz without some serious depth behind them. I'd add more of that rockwool across the front wall and add a gobo style unit with depth to cover your rear wall and the door. Check out this link http://johnlsayers.com/Stuff/components.skp

Ok John The pcture in sketchup i had posted before (picture name room 2) is showing the front wall of my room.The red thing is maybe gobo?,mdf box -one side open filled with rock wool 20cm and air gap 10cm behind.Dimensions are 150cm x 175cm x 30cm depth.Is this a gobo?? The picture (room 3 Beckwall) posted before is also showing red thing like poreose absorber 100 cm x 265cm x 30cm depth but without air gap the whole depth is rockwool. The Helm holtz resonators in the corners are 75cmx75cm in base and 265 cm high.Why you think they do not work on 30-45-68hz?I made some tests,and they resonat on those frequences.(generating sinewawe in front of the helm holtz box and mesaure with the microfon inside the box). Thanks John.

wow - well it appears your resonators work, you've got an angular front, the red units are what I was referring to......could it be a problem in your speakers??

Hi Jonh It could be the problem in the Speakers but I doubth,the speakers are -ScanSpeak( revelator seria),one midrange driver,one high and two bass drivers per box. http://www.tymphany.com/datasheet/printview.php?id=318 http://www.tymphany.com/datasheet/printview.php?id=84 I can not find link for bass drivers in this moment but I will It is true that my speakers are made DIY but the designer is in bussines 20 years allready.I produce the boxes myself (I own small Furniture factory) on the pictures below are my speakers. Ok John do not give up on me I still need help!!

well I'm away for a couple of days to the coast - all I can suggest at the moment is you hang an angled cloud over the listening/speaker area - - the idea being to stop floor to ceiling low end standing waves - as an experiment you could try lifting one of those gobos up above and angle it with the cloth on the bottom.

Thanks a lot John I will try that. Have a nice trip.

Hi John I have tried angeling the ceiling,gobo was very heavy :? so i had to make construction to hold it.But no result.So John what do you think what should I try next? Maybe my whole design is wrong???

what happens when you put your speakers hard up against the front wall?

Ok John after place speakers max to back (agenst corner Helmholtz) the result is on the picture.When I listen the music the problem remain.

The panels certainly stop working at 125hz from reading that diagram.

Duki - I said further back in the thread that maybe you need more treatment - if you add up the surface area of the room it's around 110sqm - your treatment in the corners would account for around 6sqm or approx 5.2% of the surface area. You have some diffusion at each end of your room because of these units but in real terms it's really not enough IMO. play with the reverb calculator in the stickeys and you'll see what I mean.

Hi John so I need more absortion for 20-120 hz,in your opinion witch frequnces should I treat(I think 60 -80 hz)?I have free space for about 600 litars of Helm Holtz together on the front and back wall ,if needed I will push more. Is it good idea to try with panel absorbers?The box for absorbers will be 40cm x260cm x37cm depth - four of them. My opinion was that 500 litars of Helm Holtz resonator is equal to 5 sqm,so I have about 3500 litars of Helm Holtz (front corners,Beck corners and two units on the side wall all of them are working under 100Hz)??