Are my bass traps reasonable or am i doing something wrong?

[Hipper]

From the pictures it looks like the corner bass traps are closed boxes, all I see is wood. Where's the opening of the boxes pointing to, the side showing the Isobond on the other picture?

Corner bass traps should be open to all sides facing the room.

they are mostly closed, yes. I built those when i had no idea and seems like i still have no idea as i was not aware (until now) that bass traps should be open on all sides facing the room
i could move them so the open side faces the room and do a measure - do you think that makes a big difference?

I also noticed that the bass traps appeared to covered with wood of sorts. The bass traps I have, bought from GIK, are covered in a sonically transparent cloth. You can buy this cloth from GIK and I would guess other places.

https://gikacoustics.co.uk/product/gik-acoustics-soffit-bass-trap/

I have the original Soffit Bass Traps with no additional pieces. They are made of a simple wooden frame containing mineral wool and covered in fabric The fabric is not only used for being porous to sound but also to protect the user from the irritation of mineral wool. Only the top and bottom have a thin piece of plywood to cover (also covered in fabric but only for appearance's sake). I don't know how mineral wool compares to your Caruso-Iso-Bond.

If you put porous fabric all around your bass traps you might also benefit from the space between the trap and your wall.

Even when you use lots of big bass traps (I have 21 GIK Soffit Traps) there will still be bass anomalies that require DSP/EQ or subwoofers (or both) to improve. I use a Behringer DEQ2496 digital equaliser (only two channel though so no good for your home theatre purposes).

 

[Flaesh]

Caruso-Iso-Bond

CIB is thermal bonding polyester; demonization of polyester https://www.thehouseofpillows.eu/polyester-shouldnt-be-in-your-bed-blog/

 

[slacki]

i will measure these days with open side facing the room. if it would improve anything, i might consider to cut the wood into pieces so the waves can easily pass through. i built them, so i can destroy them. if this does nothing, i make a big bonfire in snowy winter

 

[Geert]

Just cut 4 pieces out of the sides so you retain the edges and a cross in the middle to keep the foam into place. They will work, but don't expect miracles. You need a lot more of them for good results.

 

[retroflex]

If it's possible I'd also be interested in measurements without the boxes, just 10 of the damping units leaning against the walls on both sides of the window. But that's mostly for my personal edification.

 

[slacki]

@Geert jop thats what i was thinking about. If it would be useful in any way, i would then buy some tissue (hope deepl translated correct ) and encase them. Just wondering... why i did not encase them in the beginning with tissue and used wood instead - then i could easily lift them alone

@retroflex i will see what i can do and when i find a bit of time

 

[goat76]

i will measure these days with open side facing the room. if it would improve anything, i might consider to cut the wood into pieces so the waves can easily pass through. i built them, so i can destroy them. if this does nothing, i make a big bonfire in snowy winter

I’m not sure it will necessarily change much with the open side facing the room. To my knowledge, a corner bass trap is not built to work like a velocity absorber because there's not much sound wave movement going on in the corner anyway, it’more about sound pressure and by placing a bass trap there can be effective against room modes that originates from that place in the room.

To me, it seems like your bass traps are doing something good already, if it will be even more effective facing the room should be an easy thing to try (with the help from your friend), so try it.

One more thing. I think you should have a look at what the bass traps are doing in time domain instead of just looking at the frequency response, that's where o think absorption of all types makes the biggest difference. Look at the waterfall and RT60 Decay windows in REW and see what’s the difference are with and without the bass traps.

 

[Geert]

I’m not sure it will necessarily change much with the open side facing the room.

I am for at least 100%. Based on using truckloads of foam absorption in multiple commercial projects (recording studio's, concert and event centers).

there's not much sound wave movement going on in the corner anyway

That's why foam absorbers need to be very thick.

 

[Holmz]

Bare floors are trouble too. Try tossing some throw rugs on the floor use blankets if you don’t have carpet. Just to get a feel for how much can be gained by reducing the floor bounce. Hard reflective surfaces can also cause problems. Glass is another bad reflective surface. Pull the curtains closed. Throw pillows finally have a use. Throw them in the corners.

Do rugs help low bass?

@slacki I like your work!

 

[AdamG]

Do rugs help low bass?

@slacki I like your work!

Yep to a small degree. What they do is reduce reflectivity of hard surfaces. Floors, tables, walls, glass, certain furniture like leather couches. Tossing rugs on the floor right in front of the subs will help, big fluffy pillows in Corners and throw blankets over reflective furnishings. All little improvements that can add up and help make the room less reactive to sound bounce.

 

[goat76]

I am for at least 100%. Based on using truckloads of foam absorption in multiple commercial projects (recording studio's, concert and event centers).



That's why foam absorbers need to be very thick.

Like I said, it should be easy for OP to make measurements with and without bass traps, and also turn them around and see what is happening having the opening side facing the room.

And yes, they need to be thick for low frequencies.

 

[goat76]

A rug will of course not do anything for the bass frequencies.

 

[Geert]

Like I said, it should be easy for OP to make measurements with and without bass trap

And you also said some things which were misleading and that's what I responded to. We know absorption based corner bass traps work well, we don't need the OP to investigate. The only thing he'll get confirmed is that more is better.

 

[goat76]

And you also said some things which were misleading and that's what I responded to. We know absorption based corner bass traps work well, we don't need the OP to investigate. The only thing he'll get confirmed is that more is better.

I have not said anything misleading. It all depends on room dimensions and what room modes happening in his particular room.

Maybe you have missed it, but OP is thinking of getting rid of the bass traps all together based on frequency response alone, that's why he should measure and see what different positions do and what is happening if he take the bass traps away. And he should take extra care to see what is happening in the time domain, the frequency response is fairly easy to get right with EQ.

I don't have time or interest in a “you and me” debate.

 

[Geert]

I have not said anything misleading.

Yes you did:

• "I’m not sure it will necessarily change much with the open side facing the room": Wrong; an absorber needs to be open (at least not covered with a solid material).
• "To my knowledge, a corner bass trap is not built to work like a velocity absorber because there's not much sound wave movement going on in the corner anyway". Wrong, an absorber in a corner does work by making it sufficiently thick (which the OP did).
• "it’s more about sound pressure and by placing a bass trap there can be effective against room modes that originates from that place in the room". Wrong; there's no room modes originating out of the blue from the corner. It's sound being reflected from the corners which lead to room modes. An open corner absorber targets the incoming and outgoing reflection.

Maybe you have missed it, but OP is thinking of getting rid of the bass traps all together based on frequency response alone

Maybe you missed that after more of a page of discussion I was the one to notice his bass traps were closed, which can't work? You think it's helpful for the OP to question that?

I don't have time or interest in a “you and me” debate.

Than you should not have replied to my remark that it's crucial for corner absorbers to be open in the way you did.

 

[AdamG]

Dial back the aggression please. We may disagree but we can do that without making it personal and aggressively hostile. No one is here trying to mislead anyone and remember typed words can easily be misunderstood and misinterpreted or just not clearly convey what the author intended. Please be patient and kind to others.

Thank you for your understanding and support.

 

[slacki]

I have those 2 old RT60 from the old measurements i did, are they enough or should i create new ones?

i have no idea what they show
It could be that i changed the loudness of the sub between those 2 graphs, not sure anymore

 

[Geert]

To make anything out of the waterfalls you would need to zoom in the frequency axis so it shows 20 Hz tot 200 Hz, and the time axis to lets say 1 sec. The whole idea is that you see the room modes, which are resonances, dying out.

 

[slacki]

Need to first figure out how i can configure that generated graph so it includes only 20..200hz and 1 sec

 

[Geert]

Need to first figure out how i can configure that generated graph so it includes only 20..200hz and 1 sec

It's all in in the graph settings, but I don't have access to REW right now.

Maybe this thread can be helpful for you 'Room Measurement Tutorial' https://audiosciencereview.com/foru...om-measurement-tutorial-for-dummies-part-1.4/