Am I sitting on a one massive bass trap ?

[okan1151]

hello

i have built a stage on one end of the room out of 18mm mdf boards resting on some 8" joists and filled underneath with 3 layers of 2" rockwool between the all the joist. (stage is built for a reason not for room acoustics but other.)

i put my mini studio on this stage.. its in 340cm deep 4m wide and 275cm high, the height of the stage is 25cm. actual floor is solid concrete.

now, from what i been reading on, some of the bass traps or tuned traps are sheets of rockwool standing behind a perforated mdf or ply and acting as a resonant absorber.. some of these are perforated to react to specific frequency range, right?

does traps has to be standing vertically or could they just be lying down horizontally too?

if i would drill few wholes on my mdf floorboard (the flooring of my stage) towards the back corners of the studio, would this make my stage act as an absorber ?

please have a look at this attached picture.

i've already tried some other ways of absorption and bass trapping but i still have some issues like nulls and peaks and various frequencies (look at the measurement data), i did a rough measure with my behringer measurement mic, the 2nd image

as you can see i am very ambitious to get things right but not as knowledged as many of you , your kind contributions and advises will be greatly appreciated

thanks in advance

okan

[SAC]

Is that measurement made while driving both speakers?

While this can be acceptable fo determining bass modes (assuming a correct balance between room response and direct signal), driving both speakers will simply result in the superpositions of signals that will become manifest as additional polar lobing which will appear as comb filtering in the FR.

If so, could you please repeat the measurement twice while driving one speaker at a time with mic in the same position so that we can see the response without the additional 'created' interference. And while you are at it, if you like, you could run two impulse responses, one for each speaker and convolve the waterfall and the ETC response as well.

[okan1151]

Thank you for your response!

It was done driving 2 speakers at the same time. I dont have a carpet on my floor yet. Also back of the studio is open to the big space behind, so there could be lots of reverberation effecting the response, i ordered sound absorbing blankets from audiomute, i will use 2 layers of that as a curtain to close the studio area, hopefully this should reduce the effect of high frequency bouncing

I hope to get one in the next days also, I will do the measurements as you suggest tomorrow.

Thanks

okan

[SAC]

Just to clarify...

In a small room there is no appreciable reverberant field. But there will be specular reflections that will negatively affect intelligibility and imaging.

And while the FR and waterfall plots can help identify room modes (which you Will want to treat), the ETC can identify the early reflective sources as well as higher gain 'later arriving' reflections that you will want to treat.

[Weasel9992]

I think it's a matter of "so far, so good". The plot doesn't look all that bad, all things considered. You could probably use more bass trapping somewhere else...what do you have going on in the back of the room?

Frank

[okan1151]

thanks Frank..


back of the room, (the studio area) im going to hang two layers of audimute sound absorbing blankets as room dividing curtains. this should separate the sound leakage and reduce reverberation from the rest of my room. im going to hang them right to the column above where the turntables are.

i was thinking of changing my corner trapping to super chunks but i wonder if this work or create more problems. at the moment there is foam corner traps from floor to the ceiling fronted by 2 layers of 2" 45kg density rockwool panels.

i ordered two rolls of mass loaded barrier vinyl mat i plant to use behind the first absorbers on each side wall, hoping to even out some of the mid bass.

i dont know if all that will work. Just getting ideas from all this discussions from your great forum.

thank you for taking your time to look at it,

i will do some more measurements as SAC requested and see more profound results.

regards

Okan

[Weasel9992]

Originally Posted by okan1151

back of the room, (the studio area) im going to hang two layers of audimute sound absorbing blankets as room dividing curtains. this should separate the sound leakage and reduce reverberation from the rest of my room. im going to hang them right to the column above where the turntables are.

They're not going to do much good I'm afraid...on either count. They're simply not massive enough. Leaving the room long will make make for less low end issues, not more. Can you not just add some bass trapping on the other end of the room?

Originally Posted by okan1151

i ordered two rolls of mass loaded barrier vinyl mat i plant to use behind the first absorbers on each side wall, hoping to even out some of the mid bass.

What are you trying to do? By mid-bass are you taking about the 150Hz region, or lower?

Frank