If maximum absorption is the goal, it is probably best to reach all the way to the ceiling, but, getting close is probably enough. You most certainly can overdo any kind of treatment. I once heard a really nice setup in a very large dedicated room. But, in an adjacent storage room, there were more than fifty large ASC basstraps stored there. The person who worked on the setup removed that many excess traps that the owner had installed in the room.
Corner base trap- to the ceiling?
I see lots of corner bass traps installed where they don’t go all the way up to the ceiling. I guess bass sound waves more so accumulate in the lower side of a room, but don’t a lot of these pressure amplitudes reach the upper half? Wouldn’t it be better to have a corner base trap extend all the way up to the ceiling?
Is it possible to have too many bass traps in a room?
Why can't I edit the topic field? Yeah I discovered bass was spelled wrong because I have to dictate everything. I missed seeing the misspelling before I posted and now I can't change the damn field.
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"I guess bass sound waves more so accumulate in the lower side of a room, but don’t a lot of these pressure amplitudes reach the upper half?" Traditional cone based speakers radiate sound in an expanding circle so the sound fills the entire space. This is why people attach absorbers and diffusers to the ceiling, as well as higher up on the walls. As to whether one can have too many. Bass traps, absorbers and diffusers are like using salt in a recipe. No salt or too much salt both give you poor results. |
I have had bass traps for more than twenty five years. They come in two 3’ sections on a stand. I have always seen them like this. They have two sides (not easily detectable on the outside. Half the cylinder has reflective material under the fabric to partially reflect the midrange and treble while absorbing bass. |
@ditusa Thanks for posting that Acoustic Fields video. Makes you wonder what else we spend money on that has no real purpose. Cheers. |
I wouldn't place too much faith in Acoustic Fields. He is promoting his own solutions, and flies pretty far from a lot of the accepted acoustics theories with little in the way of real data. Having said that corners are the most effective place to treat low frequency room modes, but it can take a lot of absorption to address modes below 100 Hz. If possible it is best to identify the modes you need to address, and use a combination of speaker placement, listener position, and room treatment to provide the smoothest possible low frequency response. |
I wouldn't place too much faith in Acoustic Fields. He is promoting his own solutions, and flies pretty far from a lot of the accepted acoustics theories with little in the way of real data. Having said that corners are the most effective place to treat low frequency room modes, but it can take a lot of absorption to address modes below 100 Hz. If possible it is best to identify the modes you need to address, and use a combination of speaker placement, listener position, and room treatment to provide the smoothest possible low frequency response. Multiple (2,3,4) subs can be effective in smoothing out response as well. |
I guess my question is this: If you take out your feelings about AF, he is presenting a solution that is backed up by the numbers. Mathematically, you would want to know how much pressure you have and at each frequency. Then you would want to apply the solution that is designed to fix the issues (unwanted high pressure frequencies.) If there is another solution out there (corner bass traps) that can also be used, where is the objective data and room testing process that dictates proper performance in mitigating the unwanted frequencies? |
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Given how long are bass frequency waves, the pressure of the soundwave is highest at a boundary because the positive pressure of the wave moving toward the wall meets the positive pressure of the wave reflected back from the wall (the incoming and reflected back portion of the wave is still more or less in phase). A corner has two such boundaries making it the best place to put devices. Hence, a corner is the best location for a device trying to attenuate lower frequencies, but, people do tend to expect greater results than they deliver. But, even quite large diameter traps are not that effective at very low frequencies, so that they don't do much below 60 hz or so. Still, they do tend to smooth out bass response to some degree. The ASC tube traps have one side that is designed to reflect and scatter higher frequencies (act as diffusor), and one can thereby orient the traps to either absorb and dissipate higher frequencies or reflect that energy back into the room. You can experiment to determine which is better for your setup. |
@bigtwin , didn't mean to trigger anyone, just expressing my opinion. I followed Acoustic Fields for a while, but didn't find it useful in the end. I'm sure his consulting service has tuned many rooms successfully. I use the approach of measuring my setup with REW, and using a combination of pressure and velocity absorption, multiple subs tuned with DSP, and room setup to tame low frequency response. To each their own. |
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I doubt there is any blanket strategy as all rooms are different. I worked with GIK and made aesthetics a top criteria. I have a bench with windows behind my speakers that creates two corners. I had custom trianglular bass traps made to come up to the top of shutters so they aren’t visible from outside nor overwhelming for the space inside and to also not block the open part of the window. It improved the bass response. Could there be a better design….maybe but this worked so I am happy. |
I looked at the REW guidance. I'm still confounded why the acoustical community can't design a better interface. If you want to encourage more dsp use then they've just gotta fix this and make it easier to use. In the end it's not that difficult what's actually happening and it's only made more difficult by the stupidity of the interfaces. I suppose after considerable hours I could develop great expertise about how to use an interface but frankly I'm not sure it's worth the effort. Most choose not to get involved with dsp to evaluate the rooms because it's so damn difficult. |
Obviously i have no idea what I’m doing half the time. Knowledge in this thread is quite a bit better than the other thread but then again again I really can’t remember anything these days. Basically I think I’ve come to the conclusion that it's better to extend your bass trap all the way up to the corner. Corners have all kinds of acoustical issues Best to make them go away. |
@emergingsoul what would you consider those acoustical issues to be? |
What Dennis is saying about modes is true. But the video misses the point that most of the acoustic problems we hear in our rooms are not modal! If a mode is the major problem that needs to be addressed, then yes, it might not be that effective to try to get after it with a corner placed trap. Besides modal frequencies, there is a lot of sound that gets trapped in the front of the room, bouncing back and forth and muddying up the response at the listening position. Corner placed traps that can absorb some midbass while scattering/diffusing treble have proven highly effective. Adding more of them along the sidewalls is even better. Stacking them to the ceiling is generally going to give the best result. How many TubeTraps are too many? Ultimately you ears have to decide, and there are definitely differences in preference, with some people preferring a much more controlled room than others. But generally we can look at the RT60 time of the room, and most people don’t want it much below 0.3 seconds in the midbass and lower midrange, with some rising in the bass and upper treble. If it continues to drop as the frequency goes up, that’s what most people are going to perceive as an overdamped sound. We can also look at clarity. A good room will typically have between 10 and 15 dB of clarity across the audible band. If it gets way up above 20 dB in the treble, that could also be a sign of too much treble absorption. In some cases it’s even possible to get too much bass absorption such that the speaker’s in-room bass response starts to sag. I’ve heard reports of people loading enough TubeTraps into a room to get that to happen. That takes a LOT of big traps. |
I sell TubeTraps, and we think putting them in the corner stacked to the ceiling works great almost every time. It's not necessary to stack them all the way up to get a great result. RT60 time is the time it takes for the reverberance in a room to fall to a sound level 60 decibels quieter than the original sound. It varies by frequency, and a REW measurement can show you what it is for your room at various frequencies. |