Is room modes inevitable for an smaller room without heavy room treatment?

[sigbergaudio]

In a smallish room, is it possible to significantly reduce room modes, such that is minimally audible, for a one-person stationary listening position for up to 90 dBA at listening position. Without the use of subs, DSP and significant room treatment.

No. But it is possible to position both yourself and the sources of sound in various ways to make the room modes more or less problematic.

 

[olieb]

In a smallish room, is it possible to significantly reduce room modes, such that is minimally audible, for a one-person stationary listening position for up to 90 dBA at listening position. Without the use of subs, DSP and significant room treatment.

As you excluded most of what can actually reduce the effect of room modes in bass that leaves one possibility. Get as close as possible to your speakers: near field -> extreme near field -> headphones.
The latter is very efficient in respect to room modes.

 

[Flaesh]

you are saying SPL doesn't affect room modes much?

Yes, I think so. But this is not the first time I’ve read that people hear resonances starting at a certain volume.

 

[PristineSound]

At lower listening levels you will benefit from our reduced hearing sensitivity at the lower frequencies. So bass modes may be less apparent. You’ll still have unequal frequency response there at any given listening position. Your best bet is to play with loudspeaker position, relative to both room and LP if you can (but maybe less freedom in a smaller room).

Very good point, at lower SPL, the perception of tonal balance specific to bass is subjectively uneven, something that Toole talked about and hence the birth of the loudness feature.

I just did an experiment, using tone control to increase bass by 3 dB at low SPL, it indeed did start to activate the room modes.

 

[Chromatischism]

Forgot to add, without DSP.

Not possible. There are no physical treatments that are effective at taming room modes in the sub bass region. The waves are too big and too strong for even 6" thick absorbers to have an effect below 80 Hz.

 

[Keith_W]

I know technical people are very specific, and I do realized the question leaves a lot of uncertainty and confusion.

So, let me try again.

In a smallish room, is it possible to significantly reduce room modes, such that is minimally audible, for a one-person stationary listening position for up to 90 dBA at listening position. Without the use of subs, DSP and significant room treatment.

Edit: I am able to eliminate audible room mode (inaudible to my ears at least) of all room modes for approximately <= 85dBA at my listening position.

You might be a very lucky man and happen to have a very rare room that has no room modes. Such rooms do exist. For example, you might be living in a Yurt, or a tepee, or a medieval Japanese home with paper walls where the walls are effectively transparent to bass and therefore don't form room modes. Otherwise, ALL domestic listening rooms of normal construction form room modes, period!

If you eliminate subs, DSP, and room treatment - then your ONLY way to reduce the effect of room modes is to find a position for your speakers and listening position that is least objectionable. The majority of subjectivist audiophiles do this, and they seem to be happy. Although I put a caveat on that - they are happy because their hearing isn't as good as they think. They can hear differences between cables, but can't hear room modes .

What you need to do is the opposite of what I recommend for people with DSP. If you have DSP, you want to find a position with as many peaks, and as few dips as possible - since it is trivial to chop off a peak and very difficult to improve a dip. Without DSP, you want to find a position with as few peaks as possible since these are far more audible than dips. You can try REW's room simulator, but bear in mind that that only works for rectangular rooms. The more your room deviates from a rectangle, the less useful REW's room sim will be. Otherwise, the only way to do it is to move speakers and the listening position dozens of times, trying every permutation, until you find the least objectionable position.

 

[Flaesh]

I just read again about "audible modes" at high volume; on a local forum, the guy has some generic Warfedales.
Could this be related (also, partly?) to the change in speaker parameters with increasing power and displacement? Random example from AX:

The five graphs above are from my regular 15" home midbass with a three-inch voice coil. A long time ago, in a car with a stock audio system, the bass would change quite dramatically at around 20 indeterminate volume units.

 

[Axo1989]

Not possible. There are no physical treatments that are effective at taming room modes in the sub bass region. The waves are too big and too strong for even 6" thick absorbers to have an effect below 80 Hz.

I recall seeing a small studio room treated with custom wall-sized membrane absorbers that appeared effective (measurement-wise). Not too thick. Helmholtz resonators can work too. Tricky to design/engineer though. And maybe outside the OP’s criteria?

 

[Flaesh]

a Yurt, or a tepee, or a medieval Japanese home with paper walls

Attic made of wood chips and mineral wool:

 

[Philbo King]

Room modes are present wherever there's a room. If it's big enough, standing waves would fall into infrabass. Otherwise it depends on acoustic treatment and/or house curve EQ.

 

[PristineSound]

You might be a very lucky man and happen to have a very rare room that has no room modes.

Correction, inaudible to my ears in one listening position and <= ~85dBA at listening position. And do so without significant room treatment, no subs and no DSP.

I am aware it is physically impossible to eliminate roo mode, that is why I used the word "practical" in my OP.

 

[JRowland]

Just to be clear, I have a lot of love for DSP, my main system runs the miniDSP SHD. I also have a lot of love for subs, my main system have two SVS SB-3000.

For this secondary system in this room, no subs, no DSP.

I know you can't get rid of room modes, I was asking in practical listening scenarios, is it possible. For example, in my room and setup, below 85dBA at listening distance, in sweet spot, no audible room modes.

I would consider 90dBA to still be within practical listening.

I would not consider no room modes at any SPL and any location, that is not practical and in fact, it's just against the laws of physics.

I knew when I saw is room modes instead of the proper are room modes I should’ve just passed by. It was an easy answer until you rephrased the question. You have two easy ish solutions available to you but for your own perfectly valid reasons you choose not to use either. Most folks who really wanted your specific problem solved would probably combine both just to make sure. I’m not interested in fighting city hall so to speak so I unwatched. Nothing personal, just not my thing.

 

[Chrispy]

Just to be clear, I have a lot of love for DSP, my main system runs the miniDSP SHD. I also have a lot of love for subs, my main system have two SVS SB-3000.

For this secondary system in this room, no subs, no DSP.

I know you can't get rid of room modes, I was asking in practical listening scenarios, is it possible. For example, in my room and setup, below 85dBA at listening distance, in sweet spot, no audible room modes.

I would consider 90dBA to still be within practical listening.

I would not consider no room modes at any SPL and any location, that is not practical and in fact, it's just against the laws of physics.

Without the help of hardware seems you're better off just using a better dimensioned room to start....that near cube shape comes with so many issues....

 

[Chromatischism]

I recall seeing a small studio room treated with custom wall-sized membrane absorbers that appeared effective (measurement-wise). Not too thick. Helmholtz resonators can work too. Tricky to design/engineer though. And maybe outside the OP’s criteria?

If you can cover an entire wall, you might have a chance. But you'd also have to face those with hard panels to not kill the high frequencies.

But most homes can't afford to give up over a foot of width for absorbers.

 

[Axo1989]

If you can cover an entire wall, you might have a chance. But you'd also have to face those with hard panels to not kill the high frequencies.

But most homes can't afford to give up over a foot of width for absorbers.

Mass-loaded vinyl membrane or diaphragm absorbers don't affect the higher frequencies. It's straightforward to use the entire back wall area (for example) if necessary. Depending on design criteria, they may be 100-300 mm deep, usually. In a framed building you may be able to use the wall thickness as part of the absorber device, providing say 100-150 mm of the required depth (which may be all you need). In a concrete building, not really.

 

[sigbergaudio]

Correction, inaudible to my ears in one listening position and <= ~85dBA at listening position. And do so without significant room treatment, no subs and no DSP.

So what did you do? Sounds like what you're saying is that you have found a solution where at lower levels, you are not bothered by the room modes, which is nice. They're still there all the same.

I am aware it is physically impossible to eliminate roo mode, that is why I used the word "practical" in my OP.

I am not sure your question makes much more sense by adding "practical" to the sentence. The answer is still no. I for one still don't quite understand what you're asking for. You're at the same time saying you understand you can't get rid of room modes, but you are still asking how you can get rid of room modes. It would be helpful if you tried to elaborate or rephrase what you are trying to figure out.

 

[antcollinet]

A long time ago, in a car with a stock audio system, the bass would change quite dramatically at around 20 indeterminate volume units.

That might be a case of the "room" itself resonating.

 

[amirm]

Anyone successfully rid of room modes for a smallish room for practical listening scenarios, (without extreme room treatment and using multiple subs for bass management).

Since bass is mostly mono in stereo music, you can place your speakers width-wise to cancel those modes. This is from an old presentation by Dr. Toole:

For length dimension, your seating position can be varied to reduce peaks and dips (although latter is more important).

 

[Arindal]

If you have DSP, you want to find a position with as many peaks, and as few dips as possible - since it is trivial to chop off a peak and very difficult to improve a dip.

While it is a good idea to find a position with lesser dips, high peaks are also not desirable. It might be possible to correct their amplitude for one specific listening position and a certain level of mode excitement, but almost certainly with a very pronounced peak, you end up in getting non-linear dynamic effects, particularly expansion, audibly longer decay at higher SPL and with musical content providing extended excitement of the resonance in question.

My personal advice would be to avoid the excitement of room modes as much as possible, particularly by finding a position with the least of cancellation nulls and long-decay peaks, as well as using faster-decaying closed-box speakers, cardioids or dipoles. While this does not mean that the modes are eliminated, chances are much higher that they are excited less and the resulting problems are tamed enough to undergo successful DSP.

 

[PristineSound]

Since bass is mostly mono in stereo music, you can place your speakers width-wise to cancel those modes. This is from an old presentation by Dr. Toole:
View attachment 511403

For length dimension, your seating position can be varied to reduce peaks and dips (although latter is more important).

Thanks Amir. This completely answered my question and in the most simple and elegant way!

This is money.