Polar pressure map ( recorded, measured) is a prerequisite to locate the acoustical treatment if you expect them to be effective.
And each room is different so the room distribution can't easily be predicted. This is why there is sometime so much difference with simulation, they are usually based around the assumption your walls are reflective at all freq and it is rarely the case ( except within a bunker maybe).
The type of materials used in the built plays a role too: a typical plasterboard wall ( metal rail frame) can act as an low freq absorber too...
Celef you should read Earl Geddes research about multisub. It should help you understand why it is sensible.
Earl's approach to multisub is not the only one and other exists too ( dba) which can works as well or more to your preference. But principles behind them are well explained by Earl.
http://www.gedlee.com/Papers/multiple subs.pdf
And each room is different so the room distribution can't easily be predicted. This is why there is sometime so much difference with simulation, they are usually based around the assumption your walls are reflective at all freq and it is rarely the case ( except within a bunker maybe).
The type of materials used in the built plays a role too: a typical plasterboard wall ( metal rail frame) can act as an low freq absorber too...
Celef you should read Earl Geddes research about multisub. It should help you understand why it is sensible.
Earl's approach to multisub is not the only one and other exists too ( dba) which can works as well or more to your preference. But principles behind them are well explained by Earl.
http://www.gedlee.com/Papers/multiple subs.pdf
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i can not see that decay time will be lowered this way. my room has concrete walls ceiling and floor, sounds much like a bathroom when empty, i can not see why pulling in multiple subs would do any good here
Decay time isn't always a problem, unevenness is more important. Multi-subs bring peaks down as well as fill dips.
yes, i think too that i could do better by a different placement, but for now i want to try to get the best of my current placement. the reson for putting a lot of absorption in room corners is the high sound level build up at these locations, if i could get my absorbers to swallow the excessives freqencies i think the overall sound quality in my room would be better
yes i can see that multiple subs can do a lot of good, but how do i deal with long decay times?
For one, things work differently at bass frequencies. In any case have you noticed that decay times are associated with peaks? Multi-subs are partly active absorbers.
i am willing to hear how you would do if you where forced to use only friction absorbers alone in a room like mine, i do not mean in detail ofcourse but in general 🙂
https://www.avsforum.com/attachments/jaes_v60_5_perception_modal_control-pdf.2273992/ might give you some ideas, also the PSI AVAA C20 for the lowest decay times.
yes i often see this in waterfall plots, but i can not say that i have noticed this in room plots, i can sit in a null and not hearing the peaks but the rumble is still present within the room
Yes a AVA is a nice answer but at 3000euro piece...
I answered Celef: multisub first then acoustic treatments ( it'll still be time to see what is possible then).
In my view multisub is easier to try too: you borrow or rent some during a week end, try it see if it solve issue.
If madame have to leave the house negociate a nice romantic evening in an hotel. Works well. 😉
I answered Celef: multisub first then acoustic treatments ( it'll still be time to see what is possible then).
In my view multisub is easier to try too: you borrow or rent some during a week end, try it see if it solve issue.
If madame have to leave the house negociate a nice romantic evening in an hotel. Works well. 😉
Sorry, but I can't! Room acoustics is a critical part of good sound, but it's not shiny or glitsy. And, it's complicated. You'll be hard-pressed to find hobbyists who know much about the topic. I'm probably lucky to have studied the topic for many years, read all of the pertinent texts, and worked in the field. If you find a good website, please do let us know!
Http://www.acousticfields.com has a forum and a YouTube channel called “Acoustic Fields”. There is a lot of info on room treatment. I really like his approach. He does want you to buy his products but there is a lot of info on room treatment in there.
I understand your wish to not move anything but I'll try and make my point clearer. You wont supress your 50Hz mode by just throwing absorption into the room where you can. That resonance is defined by the room geometry alone and how you are energising it. BOTH are placement critical. The correct absorption has to be in exactly the right place for it to be effective. If you put an absorber in the null of a room mode it will do absolutely nothing.
I can highly recommend this book:
Floyd E. Toole Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms
this is useful to try and get an idea toosengpielaudio.com/calculator
thank you for the report. cool device but i really would like to have passive absorbers to perform well in my room and no active ones 🙂
good points, but where would you recommend me to place the absorbers for the 50 hz peak that is due to the front and back wall distance? it seem when i simulate my room in rew i can reduce this peak by either using thinner and less effective absorbers but on both front and rear wall or a single massive absorber on either wall, but do thinner absorbers really work together this way when spaced so far away from each other?
I can't really advise because every detail matters, and I have no practical experience of using absorbers to tackle bass issues. I've only ever solved issues like this with loudspeaker placement. I have plenty of bookshelves in my listening space which are great diffusers and one absorber on the back wall behind the listening position. If you are doing simulation in REW then I'd go with it! Good luck.
Unfortunately quite a few really knowledgeable people don’t participate at Gearslutz (Gearspace) any longer. My guess is it is because it recent years topics on Studio Building / Acoustics have been ”diluted” by those who want ”quick, easy and cheap fixes” for their rooms. Often there are no such fixes, especially in small rooms. So, experienced people got tired of answering the same questions over and over. There are some very good threads but you have to go back several years. Search for posts from people like Boggy, Jens Eklund, Rod Gervais, John H Brandt, Hannes, SAC.
A fairly new forum which has not been ”diluted” that much yet with rubbish is https://digistar.cl/Forum/viewforum.php?f=3
In any normal sized room there is no diffused sound for ”lower frequencies”, so there is no reverb and room modes rule. Decay time for a certain low frequency depends on listening position and speaker position. With a DBA setup the deacy time can be lowered at the listering position substantially. In my all concrete bunker its is around 340 ms non smoothed. If I check the largest peak about 10-12 dB at around 41-42 Hz at the very worst position (centre of room), the decay time for that bump is only about 400 ms though. If I move my position the decay time will change of course as it is the 2nd length mode.
A fairly new forum which has not been ”diluted” that much yet with rubbish is https://digistar.cl/Forum/viewforum.php?f=3
In any normal sized room there is no diffused sound for ”lower frequencies”, so there is no reverb and room modes rule. Decay time for a certain low frequency depends on listening position and speaker position. With a DBA setup the deacy time can be lowered at the listering position substantially. In my all concrete bunker its is around 340 ms non smoothed. If I check the largest peak about 10-12 dB at around 41-42 Hz at the very worst position (centre of room), the decay time for that bump is only about 400 ms though. If I move my position the decay time will change of course as it is the 2nd length mode.