Measuring and Treating Room Modes

[@mariosergiorubina]

Thanks for sharing! Greetings from Perú!.

[@21des1994]

Great explanation 👍👍👍👍

[@GIKAcousticsLLC]

Thanks! 😃

[@iDunnoMan9000]

Bruh, aren't room modes measured at half wavelengths not full? So, a 20' room would give 28Hz not 59Hz? The pressure map you show also suggests a half wavelength so...

[@elieee88]

how to learn room treatment and sound proofing ?

[@annode]

I need to trap an F#4 369.99hz 36". What material will catch it best and what percentage of it could be caught?

[@jonathanmorgan23]

Hi. I love your videos, I've learned a lot from them. Regarding the room mode calculation. I have read that the calculation for room modes is: Speed of sound / room size x 2 = How come did you get a 59hz room mode with a 6m room?

[@frankli3283]

I think he somehow did not consider half wavelength's room mode here. I don't know why. Some video says that half wave length won't effect like full lengths, I don't know why.

[@circuitbreaker8314]

The background noise in your vids is irritating

[@ijyoyo]

Thanks for sharing, what happens when it’s not a square , do these still apply ?

[@GIKAcousticsLLC]

All rooms have room modes, but in none rectangular rooms they are much harder to calculate.

[@ijyoyo]

@@GIKAcousticsLLC okay, thank you!

[@andraslibal]

What a pity that typical room sizes of 20 feet correspond to typical alternating current frequencies of 50-60 Hz ... I have a low frequency sound in my room, no it is not my ears, no it is not the hum I go out I don't hear it I come back I do. I also measured it with a good microphone and a bit of Labview code ... my best guess is a neighbor's household appliance is mounted on a wall somewhere. I need to investigate it. Thanks for the info.

[@HeavyMetalSonicRM]

I have bass traps on the front wall, but still have the problem where bass sounds better when I stand in front of my sofa and softens when I sit.

[@GIKAcousticsLLC]

There are certainly room modes that occur at different heights. I would suggest you reach out to us for our free advice on how to mitigate any bass issues you may be having and even with what you have done so far to treat your space. GIkacoustics.com/acoustic-advice/

[@Altuz]

Correct me if I'm wrong, but won't the room modes in a given room vary depending on the location of the source of sound?

[@BrunoBeltran]

Effectively not, for long enough wavelengths.

[@Rene_Christensen]

The modes are completely independent of the source. They are calculated via an eigenmode analysis where sources cannot be included. The driven response where you have source will be affected by the modes and the location of the sources and the location of your microphone.

[@bacontrees]

I'm liking it, but at 1:05 - 20 feet long, wouldn't that be 28Hz? Cheers!

[@Canadian_Eh_I]

28 hz is around a 40ft wavelength

[@bacontrees]

@@Canadian_Eh_I Yes, but the dimension is 20 feet long, so 565/20=28.25Hz, so the wavelength is around 40 feet, yes (1130/28=40.35ft).

[@yotamlifshitz]

full cycle of 20' is indeed ~56hz, but it is true that at these dimensions at half cycle the room would respond down to ~28hz.

[@Oneness100]

There is a myth about corner modes. If you use a mode calculator, it is VERY rare that you'll see corner Axial modes. In fact, of all of the room dimensions I'm punching into a room mode calculator, I have yet to see an Axial mode that only effects the corners, so putting corner bass traps without dealing with the rest of the surface isn't really going after the Axial modes. I would treat Axial modes first, as they are the biggest problems. But you have to have what I've been told at least 50% of the surfaces covered for a sizable difference. Also, how much energy at those frequencies is also important. If you are listening to music at 70dB, there's not going to be as much of a problem in the low frequencies as there would be if you are listening to at 100dB, as an example. It's also important to match the size/volume of the room to the speakers and the energy you plan on putting in the room. For treating the lower frequencies under 125hz, some would rather build thicker walls with more mass so that you don't have big bass traps all around the room, otherwise you may have to build a pseudo wall using a lot of bass traps all around the room floor to ceiling. But first you have to choose the right room dimensions for the usage. Bedrooms, even though they are becoming popular for setting up a DAW for mixing, are typically too small, especially if you have things like 8 ft ceilings, square dimensions and rooms like 10ftx10x8ft. That's just a big mess that requires too much treatment since you'll have a lot of treatment needed and you'll end up with much less usable space. Plus, 99.99% of the homes have thin walls, and are NOT designed to be used for music listening/producing applications. 2x4 studs with sheet rock and building insulation isn't that great of an absorption in the lower frequencies, especially when you get below 100hz. They also have a relatively low STC rating. Adding more sheet rock and green glue isn't going to help all that much either.

[@GIKAcousticsLLC]

Thanks Oneness, Agreed - Calculating modes is rarely 100% accurate, especially for non rectangular or asymmetrical rooms. It is always better to measure what's actually happening, as opposed to predicting what is probably happening. We also agree that surface area is the most important factor in performance, ie, having enough panels overall, and the right kinds of panels in the right roles. However, listening at 70dB vs 100dB affect the end result curve. Acoustics are a linear phenomenon. It is possible you are hearing differently, due to both normal Fletcher-Munson curves in our hearing at different volume levels, and also louder music will have more dynamic range given a consistent noise floor, so some things can become more audible above the noise floor at louder levels. But the overall response curve will be consistent & proportional across different volume levels. Building thicker walls with more mass can help some with isolation (if the details of the build are well-designed and well-executed it will help a lot), but doing so will exacerbate the bass response inside the room both because the room is now smaller, and also we are keeping more sound inside the room (less sound escapes). So if the goal is to improve sound quality inside the room it will be a step backwards, though this is sometimes necessary if stopping sound is important for what you do (and where you do it). Our bass traps in particular will give absorption results below 100hz, although if wall size is the limiting factor, this is an understandable impediment. One solution for controlling bass is our corner bass traps which are built to sit flush from wall to wall to allow for more usable space when space is limited in such cases.

[@Oneness100]

​@@GIKAcousticsLLC I have looked at a lot of different room dimensions with a room mode calculator and the corners are only associated with Tangental and Oblique modes. I have yet to find a room with corner issues with Axial modes. Since Axial modes are the biggest problem, if you have enough coverage to deal with Axial (entire wall coverage), then shouldn't that take care of the corners? Corners seem to be only about 10%of the surface. Sure, it will be an improvement to just put corner traps and nothing else but I would think that treating the entire wall will be much better difference. I've tried corner absorption and it only made a small difference IMO. I've been in rooms with the more of the surface covered with nothing in the corners and it was a much bigger improvement than just treating the corners. Obviously, one has to perform measurements because it does matter how much energy one is putting in the room. Just going with what experiences I have had.

[@GlennStanton]

actually, thin walls are excellent for eliminating LF build up in a room, of course if you need isolation, then you will need to change that...

[@Oneness100]

@@GlennStanton When you say LF, what frequency range are you referring to? Yes, I know for isolation purposes, thicker walls and lots of mass is required for full range. But standard wall construction is only designed for 125hz and above.

[@Oneness100]

@@GlennStanton Glenn, I hate to be the bearer of bad news for you, but I know someone that builds high end rooms (2 channel, home theater, vocal booths, studio control rooms, etc.). He has built AND tested practically every type of construction design/materials used to know exactly what each method will work or not work. 100hz and below require pressure based absorption, and the "cabinet' depth or wall depth needs to be deeper the lower the frequencies you want to absorb. A typical home has 2x4 studs with sheet rock. Hardly going to do anything against low frequencies below 100hz. FYI, the person I know can get +/- 1dB down to 30hz measured with his room builds and he uses his own wall construction for the walls and ceiling. his walls and ceilings typically are at least 10inch or deeper, depending on how much energy is going to be put inside the room. Thicker for large Home Theaters that have many large sub woofers.

[@user-xw5qd8dj8o]

cam here thinking he'd teach the formula to calculate lmao