I’m working on a design for a much lighter domestic version using ply and bracing - it calculates out at 21kg.
Hi @Xanthe, would be great to see some pics, when you are ready with it. I would also like to thank you for your always level headed and knowledgeable contribution to this thread. 
Enjoy your Christmas break and all the best Peter
First thing will be a cutting list, then a CAD design.
Physical construction is going to take longer.
Cutting list is mostly done (hence knowing the mass reasonably accurately!).
Hui @PeterR ,
Here is a nice tutorial explaining how to build a membrane bass trap.
The procedure is pretty well filmed and detailed.
Doing the math is the easiest part (encloser and membrane dimensions and weight).
The problem here is that such traps hit a very narrow frequency range. If your built trap deviates from your calculation, you can creat problems rather then solving them.
Lets say you have +6dB at 65Hz, and you build your trap accordingly. Unfortunately, something goes wrong, and you end absorbing 55Hz. You just created a dip you hadn’t before.
That’s why I never tried to make them myself. It takes time, has a cost, and may end up useless.
Part 1
→ Mixing Studio Build - Membrane Bass Trap Part 1 - YouTube
Part 2
→ Mixing Studio Build - How to Build a Membrane Bass Trap Part 2 - YouTube
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That’s part of the benefit of the BBC design - it’s a damped broadband membrane absorber: it has an absorbance peak that covers around a 1:1.8 frequency ratio +/- 3db, so much less critical on precision of construction and/or design modification. On the other hand you need about 2 times the area!
Hi Thomas,
Wrote a long spiel last night relaying my thoughts on your project, but having read through it this morning, I deleted it, as it had got a bit too rambly after too much Christmas wine 
Beyond agreeing with your revised speaker positioning I cannot really comment on your project due to lack of experience and the sheer amount of variables it holds. If it is your plan to play Magico M2s in that restricted space, I would personally get a Pro person on board to advise. Wonder if Jesco or Artnovion could be a possibility, don’t know……
Enjoy the Swiss church bells ringing out over towns and valleys today 
Best Peter
I liked your post and it is worth to remind everyone of the risks of perfection, I think you made the point very nicely: listen to music in an anechoic chamber and let us know if you like it.
Your post was a good blend of passion, experience, wine and Christmas.
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Hi I would use a room mode calculator to give you a steer on speaker and seating position. I would liase with somebody like Nick at GIK…he will help… I think you are heading in the right direction but I would want to add some ceiling clouds as the ceiling is a massive reflection area… assume you have rugs/carpet on the floor.
I suggest you get a UMik microphone and measure the room with REW … and send this to Nick…you will get very good advice.
Personally I think the Magico speakers will be fine…
Have a great Christmas…and enjoy your exciting project in the new year!!!
Hi Rafael, I didn’t quite say that, but…
Thank you and all the best Peter
I apologize, I didn’t want to imply that my words were part of your post.
My words are the visual summary of you going through every corner and furniture in your room, correcting any frequency imbalance and arriving to the conclusion that perhaps it was not worth it.
Did you ever visit a perfect audio room? They sound very alien to me.
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Hi @Richieroo
I’ve been using REW and a calibrated mic for about two years 
Did a lot of mistakes, then had to correct them…
REW is very very very nice toy! 
A great Christmas to you too 
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Hi @PeterR ,
I read your email this morning. It was nice, despite some inaccuracies regarding my room. You shouldn’t have erased it.
First of all, your comment regarding the family usage of the room was very thoughtful. 
My wife, my daughter and I already use it exclusively for listening to music. We don’t have a TV and if we aren’t listening to muic we’re out climbing (or working…).
So, closing the zone won’t change much except for the quality of the acoustics.
If I may, your calculations with AMROC are not correct. The room separation won’t be a hard wall, it’ll be porous. It’s just like having an enormous bass trap in the middle of the room.
As you know, AMROC mathematical model uses a parallelepiped shaped room with perfectly homogenous, flat and fully reflective walls (hard walls).
This means, we can’t avoid measurements as walls never are perfectly flat or homogenous (doors, windows, furniture, etc…) It approximates the real thing and is mainly used for rough predictions.
If I had to use AMROC, which I did, I had to enter the following parameters: 4,65 x 8,80 x 2,5. Unfortunately, the predictions are pretty wrong compared to the measured values ; the room isn’t a parallelepiped.
There will be a tremendous amount of absorption, which should guarantee an even decay time down to 50Hz.
As for being “dead”… I believe a “dead room” is a meaningless expression.
To some extent, in acoustic terms, a “dead room” is a room with an uneven decay time. The decay-time delta , between the low-end and the highs, being too big.
I’d use the term “reflective” versus “less reflective” instead of “live” versus “dead”.
And this is a matter of taste. It is purely subjective. It only depends on our preferences and how we feel in the room (as long as the decay time is even).
When building or treating a room, the key is decay time throughout the whole spectrum. Which pretty hard to achieve!
I will, of course, ask for an acoustician help. The room modifications will cost a lot (way above 20k). 
I know a few things theoretically and achieved a pretty nice frequency response with my current setup. But what I’m planning abviously requires a pro.
My speakers are the Magico S3 MkII, not the A3. 
They aren’t sold yet. So the M2 will wait until then.
The S3 MkII paired with the Naim system
I’ll take pictures of the whole process.
Merry Christmas Peter!
And thank you for your comments and thoughts!
I the meantime I’ll enjoy the holidays and do some climbing, ice-climbing and dry-tooling.
Music isn’t my main hobby
A few few years ago, same period of the year :
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Hanging around in dank caves can be fun after all! 
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The reason that I have so far resisted the room correction issue is that once you’ve got the mic and SW and learned how to use it you have then infected your conscious mind with the idea that your SQ is measurably imperfect and needs to be perfected.
It tends to lead to a windowless cell with perfect acoustics.
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Looks to me that @Thomas is not afraid of a good challenge 
Good luck with your room and all of the first hand knowledge that will result from the experience. Please share with the class as you move through your build!
ATB,
Mark
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Hi Thomas, yes sorry not really fully up on the Magico range 
It’s a very brave project Spiderman! 
Stay safe and Merry Christmas Peter
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Recently looked into Artnovian here in the states really at @Thomas mentioning,and they referred me to the local distributor who will be referring me to a relatively nearby retail acoustic designer that will use Artnovian products. I plan to have them come over and see what they propose.
Have a feeling it will be rather expensive but let’s see.
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Windows are overrated!
I might leave some sunlight through by placing some transparent diffusors on the leftside.
Abviously I’ll have to do the same on the right side.
The good thing is that 42 cm deep quadradic diffusors have a nice diffusing range.
→ Calculate Quadratic Residue Diffusor ( estimated design frequency )
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It’s easy to forget that we don’t all have the same end goal when it comes to hifi. Some strive for absolute perfection and some are just happy with the equipment placed where it fits. It’s hard to know how much of it is a love for the music and how much is a scientific experimental endeavour. Maybe something in between I imagine. I can certainly understand it but it’s not for me. For me, part of my enjoyment is having a nice open space where we can socialise with family and friends and move around the room, and house, and still hear the music. I like to lay on the couch and look out the windows whilst listening to music and sometimes dose off to a nice relaxing album. It’s that part of @PeterR ’s post that resonated with me. Taking space away from the family environment and removing light and openness. However, I might be imagining something else entirely and I haven’t seen the rest of the house so I shouldn’t comment. Good luck with the plan @Thomas , it will be fun to watch the progress.
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