I've been through a room treatment for my movie room where I had it measured, then acoustic treatments applied accordingly.  This included SpringTraps for bass management.  Unfortunately we can't get SpringTraps in Australia anymore.  If we could my problem would be solved, they're so effective below 100Hz.  The room I'm looking to treat is my living room where I have large speakers, Osborn Epitome.  No matter where they're placed, they're quite heavily corner loaded.  It was cramped for space over the last few years because I was running monos, but I'm recently moving back to integrated amplification so there's some space for corner treatment.  I don't have any intention to take room measurements, just place some traps in the corner and see if they're effective.  If so then I'll install them.  There's a couple of products on the market that I'm curious about, so keen to hear any opinions. 

 

Sound Acoustics LF65 BEAR series.  With the insert installed they're effective from 63Hz -

 

https://soundacoustics.com.au/product/bass-traps/lf65-corner-bass-trap/

 

 

 

Sonitus Decotrap.  Claims most effectiveness between 60Hz - 250Hz.  That's a large range, I couldn't find any data showing exactly how effective.  @GC Hifi can you add to this?

 

https://gc-hifi.com.au/products/decotrap-natur-sold-in-a-pack-of-2 

 

 

 

Artnovion Ulysses.  Data shows good effectiveness around 50Hz - 100Hz -

 

https://www.spacehifi.com.au/artnovion/artnovion-ulysses-bass-trap-wall

 

 

 

 

Primacoustic Full Trap.  Drops at 63Hz but still effective, and very effective around 80Hz -

 

https://www.soundseasy.com.au/products/primacoustic-fulltrap

 

 

 

 

 

 

For the record I contacted Selby Acoustics about their Extra Large Dunlop Foam traps, and their graphs did not show any data below 100Hz.  Having said that, that data showed they're fairly ineffective below 180Hz anyway, so these are ruled out.

I've got a couple of Primacoustic Fulltraps in the front corners and other people seem to think they look cool. 😎
 

If you are looking for something substantial I don't think any of these products do that. I think most of the products you've linked to do next to nothing under 100Hz and minimal under 200Hz. You need EQ under 200Hz to really make a controlled difference. I'm not saying don't do, but I am saying have low expectations.

2 hours ago, Satanica said:

I've got a couple of Primacoustic Fulltraps in the front corners and other people seem to think they look cool. 😎
 

If you are looking for something substantial I don't think any of these products do that. I think most of the products you've linked to do next to nothing under 100Hz and minimal under 200Hz. You need EQ under 200Hz to really make a controlled difference. I'm not saying don't do, but I am saying have low expectations.

 

Yes I remember the door in your room!  I take it from your response that you found the Primacoustic to have minimal effect?

 

No I'm not after substantial, in all honesty this isn't a significant problem.  I'm more looking to see if there's improvement in tightening the bass and, if so, then I'll keep it.  It's good to get your feedback though because looking at the graphs is only a fraction of the story.

26 minutes ago, Kaynin said:

Yes I remember the door in your room!  I take it from your response that you found the Primacoustic to have minimal effect?

 

No I'm not after substantial, in all honesty this isn't a significant problem.  I'm more looking to see if there's improvement in tightening the bass and, if so, then I'll keep it.  It's good to get your feedback though because looking at the graphs is only a fraction of the story.

 

I think it made a subtle improvement, just nothing that your non-audiophile will notice.
When I turn Dirac Live ON/OFF my other half says that the difference is huge and appreciates that bass sounds too loud and bloated without it.

I've since taken better notice and I actually have the place in the corner MaxTrap, not the FullTrap.
They are only made of particle board so I painted the inside and the edges with a sealant.
The price increase since  when I purchased mine is not funny.


If not already done so, have you considered Dirac Live Active Room Treatment (ART)?

12 minutes ago, Satanica said:

have you considered Dirac Live Active Room Treatment (ART)?

 

Yes but not interested, looking at passive bass traps at this stage.  🙂

@Kaynin ,

I don't think anything is available "off the shelf" in passive bass traps that work well <100Hz.

• Broadband absorption/velocity traps get too large/deep/gapped to be practical below 150-200Hz or so.

• Membrane/pressure traps can work down low, but are narrow-band, so need to be designed for their operating frequency...and also need to be large/deep (but not gapped) to be effective <100Hz.

• "Lossy" membrane traps using limp mass membranes like Mass Loaded Vinyl, have broader absorption characteristics, but still need to be "designed" for their operating frequency, and again need to be large/deep to be effective <100Hz

• VPRs are an option - reach out to @acg - likely the smallest form factor option

Primacoustic use limp mass in their MaxTrap and FullTrap bass traps, but my understanding of the science says the limp mass membrane requires a sealed enclosure behind (filled with absorption), which neither the Primacoustic MaxTrap or FullTrap has....

Keep in mind pressure traps work best in high pressure areas (ie adjacent to walls), whereas velocity/absorption traps work best gapped from walls (room modes have the highest velocity 1/4 wavelength away from a rigid boundary).

ie:

• Always straddle a corner with an absorption/velocity trap

• Always place a membrane/pressure trap against a wall.

Mike

@almikel thanks Mike.

I have a pair of SpringTraps that work INCREDIBLY well in my movie room, but unfortunately you can’t get them in Australia anymore. I was hoping another product would go close, but it appears not.

Having said that I moved on my monos and pre and have gone a pure class A integrated, and the bass control is superb. Also there’s more room so the speakers have been moved out of the corners. I don’t feel I need bass traps with the current set-up.

Edited December 30, 2025Dec 30 by Kaynin

A few years ago I had time and not lots of money :) Now I have either

Had a go at building some passive "anti speakers" as I like to call them, but in fact are limp membrane bass traps for a lounge room I had just finished renovating, big ones, man sized 2 man lift.

Short back story

The job was an attempt to tame 2 pairs of 21" pro neo drivers in 650 liter ported enclosures, with an effective band pass of 23Hz F3 to 300Hz, first crossover point. Efficient at 99dB for 2.8v ,,,,

The room the speakers were housed, has double layers of plaster, ceiling and all walls, double glazing and partly enclosed heavy custom made roller blinds. The walls were built from the old 100 x 50 hardwood, clad in seasoned macracarpa 25mm thick boards on a layer of 10mm foil board, then the normal R2.5 wall bats. All that was an effort to partly sound proof the light weight suspended room,,,which it did, to some degree.

The caveat was a poor acoustic environment, measurements showed 10 to 20Hz leaked out of the room ok, however from 40Hz and onwards, with peaks at 55Hz, 120Hz, 210Hz, were significant room resonances, measured in REW, with a miniDSP UMIK 1. Beyond those frequencies and into directional radiation severe comb filtering was present, even with the constant directivity 2 way horn set.

What to do ?

Well after a few phone calls a Bloke offered me a 65Kg, 12m roll of weighted vinal with a closed cell layer of foam at 8mm thick bonded to the back of it. Underground truck cab liner apparently. Donated, for a favor.

I had some experience with limp membrane trapping in the past so decided to give another design a crack.

Without going into a lot of measurements, design, construction method, the job can be summarised, in saying a hardwood frame was bugle screwed (made part of the building structure) to the walls to house the limp membranes, which were air tight sealed to the wall and filled behind with CSR heavy acrylic bats. Essentially like a loose drum skin, sealed and damped. To get around the narrow operation band widths, which each membrane was sketchily measured at each trap has differing length dimensions and the largest, was a double membrane. I guessed in all practicality, but had done before and after measurements. I tried throwing a tennis ball at the traps and measured the response, a golf ball and some others :).

Directly in front of the membrane, was damped with 25mm CSR Acrylic sheets and covers of upholstery material as a primary trap for higher frequencies. Each membrane had a small still air gap behind it.

So, about 40 days of labour went fast and the things were on the walls along with some surface mounted, 40mm thick ceiling panels.

Cured the combing and made measurable effect in tuning down the room resonances a the targets of 200Hz and below

The photo is of the system how it was a couple of years ago, the only other treatment was to use Sorbothane all over the system, 12 under the 21" enclosures and also under the horn set.

The Sorbothane pucks made measurable differences at below 50 Hz and was the icing on a very nice set up, DSP tuned and calibrated over a full 8 channels.

Made the room sound like it was larger with the speakers sounding like they were further away, deeper soundstage, fantastic stereo image from the horns.

playdough.

PS, you can not buy some things, they have to be made.

There is a full build thread buried deep in the past on this forum, Bass Trapping a new sound lounge, or something like that if interested.

That room looks much neater these days, carpet is now symmetrical as well as the speakers, to the mm and has had several calibration sessions, since. Waiting for me to get home.

23 hours ago, almikel said:

@Kaynin ,

I don't think anything is available "off the shelf" in passive bass traps that work well <100Hz.

• Broadband absorption/velocity traps get too large/deep/gapped to be practical below 150-200Hz or so.

• Membrane/pressure traps can work down low, but are narrow-band, so need to be designed for their operating frequency...and also need to be large/deep (but not gapped) to be effective <100Hz.

• "Lossy" membrane traps using limp mass membranes like Mass Loaded Vinyl, have broader absorption characteristics, but still need to be "designed" for their operating frequency, and again need to be large/deep to be effective <100Hz

• VPRs are an option - reach out to @acg - likely the smallest form factor option

Primacoustic use limp mass in their MaxTrap and FullTrap bass traps, but my understanding of the science says the limp mass membrane requires a sealed enclosure behind (filled with absorption), which neither the Primacoustic MaxTrap or FullTrap has....

Keep in mind pressure traps work best in high pressure areas (ie adjacent to walls), whereas velocity/absorption traps work best gapped from walls (room modes have the highest velocity 1/4 wavelength away from a rigid boundary).

ie:

• Always straddle a corner with an absorption/velocity trap

• Always place a membrane/pressure trap against a wall.

Mike

Happy New Year Mike, I love reading your posts.

Same to you @Kaynin All the best and sorry if you have heard this story before ,,,,

On 30/12/2025 at 9:33 PM, Kaynin said:

Having said that I moved on my monos and pre and have gone a pure class A integrated, and the bass control is superb. Also there’s more room so the speakers have been moved out of the corners. I don’t feel I need bass traps with the current set-up.

Hi @Kaynin that's a great outcome!

Hi @playdough - happy new year to you also!

Always enjoyable reading your posts also - your willingness to build and experiment with stuff amazes me!

On 31/12/2025 at 8:30 PM, playdough said:

There is a full build thread buried deep in the past on this forum

I couldn't resist finding it to read again!

Acoustic Panels and Bass Trapping a new lounge - Room Acoustics, Construction and Design - StereoNET.

What an opus!

Super interesting to go back over your journey.

Mike