Software to kill a room mode

[CaliRob]

Hello,

Sorry if my question has been covered before. I have basic knowledge of acoustics so I know it all really starts with treatment but I have a room with ceilings the same height as one of the walls distances that is giving me a really annoying mode in the low end. Is there some software I can purchase or free for Mac that essentially allows me to put a filter over my Apogee Duet output where I can enter in a few frequencies to notch out. I can figure out these frequencies myself and I don't really need a measurement mic + correction program though if there is a option out there with this that people recommend, i'd love to hear it. For now I'm just trying to keep it basic. The resonances are in the sub 50 Hz range and they are driving me crazy.

Thank you for your time.

[CaliRob]

On second thought the mode must be in the 70s right if the wall and ceiling are 8 ft, a 16ft wavelength tone should be the culprit right? Anything lower than that should be ok as my sub doesn't go below 40? Sorry if this is basic. Haven't studied sound in 7 or so years when I did my physics undergrad... Pretty rusty.....

[James Perrett]

If you never move your head then you can possibly do this with eq but, if you move your head just a few cm, you will need to change your eq settings. It would be far better to treat the room rather than mess around with eq.

[Logarhythm]

Think James' point is very valid and eq is unlikely to work as a solution in practice - bit of a shame as a nice idea that would make life easier for a lot of smaller studios!

Think you're also going to find that whilst the wavelength of the mode is fixed by the room geometry, the actual frequency you're trying to EQ is effectively variable?
Off the top of my head I'm not sure how pronounced the effect will be, but as the speed of sound isn't fixed and will vary with temperature, humidity etc and is linked to wavelength and frequency by v=fλ, for a fixed λ (determined by where your walls are) a change in v will change f, i.e. the frequency at which you hear the mode occur won't be fixed.

P.S. Ref. the sub output, if 40Hz is quoted as the -3dB point then it will most likely still be outputting something below this - exactly what will depend on the sub itself. If it's a ported box then it will probably fall away quite sharply and may be negligible, but if it's sealed cabinet then the roll-off will be more gradual.

[Music Wolf]

Off the top of my head I'm not sure how pronounced the effect will be, but as the speed of sound isn't fixed and will vary with temperature, humidity etc and is linked to wavelength and frequency by v=fλ, for a fixed λ (determined by where your walls are) a change in v will change f, i.e. the frequency at which you hear the mode occur won't be fixed.

Between dry air at 0degC and 20degC the speed of sound varies by about 3.5% (faster for warmer air). It all contributes but I think that variation in listening position will have the bigger impact.

Fixing the room electronically has been something of a Holy Grail for monitor manufacturers for a long while. The solutions will get better with time - unfortunately my hearing is getting worse with age so, sadly, I don't suppose that I will ever exerience the benefits.

Thank heavens for Rockwool

[CaliRob]

I am always in basically one position in the room within a square foot or so and the offending frequency is just this crazy resonance around 52 Hz. I just checked it and 70 Hz is actually cancelled out which makes sense given the geometry. Been a while since I thought about this stuff. Anyhow if I can just attenuate that one frequency, I'd be happy. It's just so annoying. I know that treating the room is the best option for sure. But until I can move into a bigger spot or buy my own hose to get crazy with wall and corner panels, this isn't an option.

Any software do this at all the piggy backs on some interface like the duet?

Thank you for any input. Much appreciated.

[benniferj]

Well, if you want to give it a go, chuck a parametric or graphic EQ on your main out from whatever sequencer you're using… sweep away and see if you remove a big boomy annoying hump in what you're hearing. It isn't a technically sound way of achieving a flat and even listening spot, but if there's one notable frequency that goes mad, you can help yourself with this. It's free, anyway!

[Hugh Robjohns]

Any software do this at all the piggy backs on some interface like the duet?

There are loads of DSP solutions for this: CONEQ, ARC and many more besides.

However, if you just want to tame a strong single resonance, then a standard notch EQ plugin or parametric EQ plugin will do the job. Just make sure it lives only in the monitor outputs or, if it has to live inthe main outputs, don't forget to remove it before bouncing out your mix!

It's also worth noting that while you can tame the amplitude peak in this way, you're not curing the problem or fixing the associated time-domain issues, and you can't realistically do anything about the 70Hz cancellation since the speaker won't be able to fill the acoustic null. Only serious bass traps can resolve such issues properly.

H

[Tomás Mulcahy]

Isn't the calculated room mode a simplification? As pointed out, it doesn't factor in temperature and humidity. It also doesn't account for what the room is made of. Won't that skew the figure a little bit, so it's better to measure it?

But +1, put in SOME room treatment at least. Otherwise with the eq it's just like fixing bubbles in wallpaper by pressing on them (they pop up somewhere else).

[Mixedup]

It's better to measure it?

But +1, put in SOME room treatment at least.

+1. Put in some treatment, including decent corner traps. Then measure so you know what the real-world problems are. Then tackle the problems you can. Then resort to EQ or whatever. Otherwise you'll be chasing your tail for forever and a day and you'll never have the confidence in the room that you need to get on and mix without distraction.