How many more panels do I need to build?

here are two clips

one is processed with de-essing, couple of EQ low end roll offs, compression and some volume adjustments.

sorry for the hiss or air in the background, I recorded it pretty hot.

FWIW.. neither has what I'd consider a problem or 'boomy in the low end. The 'treated one obviously with trimmed low end, my preference would be the 'untreated somewhere between the 6 and 10 inches depending on taste and fit.
 
This is my first post in the 4 years of my membership. My reason for joining was to learn about live recording. Many years ago, I learned a lot from musicians when designing speaker systems for them. I soon discovered that such an endeavour was extremely different than that of a sound reproduction system which, ideally should not alter the sound. From a musicians point of view, the loudspeaker is part of their instrument and they, and only they, have the right to determine how that speaker should sound. I was humbled and if I may extoll my achievements, very successful.

This post caught my attention after listening to the two recordings. What I noticed is a low frequency difference in both recordings, some of these differences being affected by your distance from the microphone.

While the room itself can make or break any sound system, the phenomenon mentioned above may be due to a phenomenon called proximity effect. It's an enhancement of low frequencies that is dependent on the distance of the source to the microphone. Not all microphones are affected by this. There is a plethora of information on the net. Some microphone manufacturers may supply this with their microphones.

As can be seen by the Sound Absorption Chart provided by Mr. Keith Rogers, post #13, the effect of absorption below 125hz is extremely low, rendering the term "bass trap" synonomous to an oxymoron. One easy way to tame these bass peaks is with a 31 band graphic equaliser or better yet, a parametric equaliser. By far, the best way is an anechoic chamber or outdoors at least 50ft from any reflecting surface other than the ground. However, the latter two are grossly impractical and neither will tame proximity effect.

If using an equaliser, the best way is to attenuate the peaks and ignore the dips as they are dependent on room dimensions vs wavelengths. An analogy to boosting the dips would be stepping on the accelerator of your car while pressing harder on the brake; the car won't move. Some equalisers only attenuate; they do not boost but they seem to be rare.

Attached is a graph showing the effect of distance on low frequencies. This microphone is a Behringer ECM8000, primarily a measurement mic. Broadcast microphones, I believe, are very sensitive to this phenomenon, so much so that some late night radio show broadcast announcers would speak softly and very close to the microphone, resulting in a soothing and relaxing sound to the listener.

Robert

D01730.JPG
 
Last edited:
This is my first post in the 4 years of my membership. My reason for joining was to learn about live recording. Many years ago, I learned a lot from musicians when designing speaker systems for them. I soon discovered that such an endeavour was extremely different than that of a sound reproduction system which, ideally should not alter the sound. From a musicians point of view, the loudspeaker is part of their instrument and they, and only they, have the right to determine how that speaker should sound. I was humbled and if I may extoll my achievements, very successful.

This post caught my attention after listening to the two recordings. What I noticed is a low frequency difference in both recordings, some of these differences being affected by your distance from the microphone.

While the room itself can make or break any sound system, the phenomenon mentioned above may be due to a phenomenon called proximity effect. It's an enhancement of low frequencies that is dependent on the distance of the source to the microphone. Not all microphones are affected by this. There is a plethora of information on the net. Some microphone manufacturers may supply this with their microphones.

As can be seen by the Sound Absorption Chart provided by Mr. Keith Rogers, post #13, the effect of absorption below 125hz is extremely low, rendering the term "bass trap" synonomous to an oxymoron. ...
Just quickly I wanted to point out that the 6" Safe'n'Sound number at 125Hz is pretty good.

The one inference I take from that chart is that 1.15 seems to be the asymptote of the absorption number you might expect to get from any material.

It's a shame they don't measure 50/60Hz in that standard, because that's just as important to us. Getting that number over 1.0 might take 12". It would be nice to know.

And, maybe I'm reading this post too quickly, but the "elephant in the [small] room" we're trying to address most often in home studios is the incorrect perception of bass when we listen back on monitor speakers that is caused by inadequate treatment and, typically, room size/dimensions. the result we usually have is that we cannot mix the LF content correctly, and often, it's mixed too low because it sounds louder in the room than it really is. There may be other frequencies that create problems on mixing as well as recording, but most of the time, we are close micing because we do understand the room is not going to add to the recording in a uniform way. (And, yes, the close micing can add bass from proximity effect, but that's not a "studio building" problem.)
 
In a room that small, you really can't have too many bass traps. But if you're not recording drums or live instruments it will be a little easier.
 
This is my first post in the 4 years of my membership. My reason for joining was to learn about live recording. Many years ago, I learned a lot from musicians when designing speaker systems for them. I soon discovered that such an endeavour was extremely different than that of a sound reproduction system which, ideally should not alter the sound. From a musicians point of view, the loudspeaker is part of their instrument and they, and only they, have the right to determine how that speaker should sound. I was humbled and if I may extoll my achievements, very successful.

This post caught my attention after listening to the two recordings. What I noticed is a low frequency difference in both recordings, some of these differences being affected by your distance from the microphone.

While the room itself can make or break any sound system, the phenomenon mentioned above may be due to a phenomenon called proximity effect. It's an enhancement of low frequencies that is dependent on the distance of the source to the microphone. Not all microphones are affected by this. There is a plethora of information on the net. Some microphone manufacturers may supply this with their microphones.

As can be seen by the Sound Absorption Chart provided by Mr. Keith Rogers, post #13, the effect of absorption below 125hz is extremely low, rendering the term "bass trap" synonomous to an oxymoron. One easy way to tame these bass peaks is with a 31 band graphic equaliser or better yet, a parametric equaliser. By far, the best way is an anechoic chamber or outdoors at least 50ft from any reflecting surface other than the ground. However, the latter two are grossly impractical and neither will tame proximity effect.

If using an equaliser, the best way is to attenuate the peaks and ignore the dips as they are dependent on room dimensions vs wavelengths. An analogy to boosting the dips would be stepping on the accelerator of your car while pressing harder on the brake; the car won't move. Some equalisers only attenuate; they do not boost but they seem to be rare.

Attached is a graph showing the effect of distance on low frequencies. This microphone is a Behringer ECM8000, primarily a measurement mic. Broadcast microphones, I believe, are very sensitive to this phenomenon, so much so that some late night radio show broadcast announcers would speak softly and very close to the microphone, resulting in a soothing and relaxing sound to the listener.

Robert

View attachment 107153

Hi Rob, also, everyone who is contributing to this thread, thank you for the feedback and taking your time to share valuable information. .

Robert, do you think proximity effect would come into play even when I was a good 6 inches away from the mic at the point in the recording where I said I was approaching the microphone?

One last question, can I use polyester as a material to wrap around the traps? Is it breathable enough? I saw good prices for a msterial that consists mostly of polyester mixed with 5 to 8 percent spandex, is it breathable enough for absorbtion panels slash bass traps?

The coefficient at the lower levels of rockwool safe and sound is at .5 at 3 inches, technically, if I double the depth of the panel and put 2 batts in to make it 6 inches deep,does it increase the absorption coefficient of the panel up to 100%?
 
Hi mixsit, I did that processing to try to neutralize the vocal or balance it a bit, my preference is the unprocessed one sonically,
maybe with a bit less bass in there. 2 or 3 db parametic eq at 125 to lower.

The issue is I record hip hop songs and the high emphasis of the music is centered around the bassline or kick drums, usually both are highly compressed and accentuated in instrumental track I record to and generally that is how the genre sounds, thus my vocal on the low end needs to be trimmed down or carved a bit not to muddy up the mix or clash with other more prominent parts of the low end ontwo-trackk mixdown instrumentals I receive from producers for me to record vocals over.
 
Too good times, yeah, I am good with dead if I dont loose detail on the high end I am recording. Just 8 4 x 2 feet by 3 inch deep with the insulation I mentioned made great improvements for the sound of the vocal recordings, I still had a bit of a reverb in the room, a slight amount. I am making 8 more panels now and will see how it turns out
 
Back
Top