Reinforce or treat front wall (or both)

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

Moderators: Aaronw, sharward

intrancewetrust
Posts: 5
Joined: Sat Apr 18, 2020 11:22 am
Location: Tasmania, AU

Reinforce or treat front wall (or both)

Post by intrancewetrust »

I am wondering if its advantageous to reinforce my front wall, I am using front ported monitors and dual subs squashed against the front wall at basically 1/4 and 3/4 positions, so using the front wall to 'launch' a plane wave. I have read in some document (maybe neumanns?) that the front wall should be double layer plasterboard... being a house that already well and truly built however I am left with layering something over the existing wall. I am thinking 19mm MDf might be pretty good for this purpose, its certainly a lot more solid that a sheet of plasterboard. So not sure if its best to just leave it, add plasterboard of add MDF. Just to confound things I am currently putting in bass traps and had in mind to trap the front corners, but I am not sure if this is a smart move if you are using the front wall as a launch pad ? If anyone could help me weigh up these options it would be much appreciated! Thanks

Also the bass traps are pretty beastly, the front wall will be 1200 x1200 x100 mm acoustic polyester panel (CSR polymax XHD) straddling the corner and the void stuffed with fluffy polyester ceiling batts. So hopefully a bit more effective than a stick on foam block!
Paulus87
Senior Member
Posts: 652
Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Reinforce or treat front wall (or both)

Post by Paulus87 »

Beefing it up is definitely a good idea - but, if you're going to the effort of boarding then why not simply build a whole new front wall in to which you can flush mount your monitors? Then you can use some of the void behind the new wall as bass traps.

If you decide to do as I described then there's two ways of doing it - you can either build it completely sealed in which case your front wall baffles would come out at the desired toe in angle for your speakers, then they would connect back on themselves to the front wall leaving a space in the corners for your corner traps, or you can build a whole new front wall with cutouts for your speakers and cut outs for your bass traps. A bit like a massive ported speaker enclosure.

I can draw up some ideas if my descriptions are not clear, let me know what you think?

Paul
Paul
DanDan
Senior Member
Posts: 637
Joined: Tue Mar 25, 2008 3:31 am
Location: Cork Ireland
Contact:

Re: Reinforce or treat front wall (or both)

Post by DanDan »

I recommend acoustically measuring the space to see how it is behaving currently.
This would include experimenting with sub locations and running the Sats full range if they are big enough.
Those corner traps seem very wide? I reckon it would be better to straddle floor to ceiling whatever width.
Can you link to that Polyester material. I am a big advocate of Poly.
There is a mongrel option. You could treat the whole front wall with deep fibre. Probably sink the speakers into it so they are still almost Flush with the FW.
Or place them a decent distance (over 2M) away from the FW.
In any case, be advised by testing.
intrancewetrust
Posts: 5
Joined: Sat Apr 18, 2020 11:22 am
Location: Tasmania, AU

Re: Reinforce or treat front wall (or both)

Post by intrancewetrust »

Thanks for the thoughts gentlemen... Dan here is the poly im using for the front of the trap (XHD100), the stuffing is just standard ceiling polyester batts

https://www.bradfordinsulation.com.au/- ... 60C5C0CABB

Building soffits is a really good idea Paul, however it seem like it would be a lot more work than just putting some MDF on the wall? Basically the wall is so small (2.3 x 2.2m roughly) that it only takes 2 sheets to cover it and I already have one sheet spare at home. So to mdf the whole front wall just requires me to buy one sheet of mdf. In my mind soffits require framing/studwork and recessed areas to place the speakers etc... but please do send a link or image perhaps its easier than I thought. The other reason I have not really considered soffits is that I will probably change my monitors once I have finished treating the room which might require different spacing, angles and sizes for the cutouts?

the reason the bass traps at the front are square is so I can leave space along the front wall to place the subwoofers, I want to leave enough gap between the floor and the bottom of the bass traps to let me place whatever sub I happen to want to use up against the front wall. space is really tight as the wall is only 2.2m wide, so by lifting up the bass traps it leaves some room to work with by sliding the subs under the traps... I can make them 1.8 tall but this leaves enough space for only more compact subs to fit under the traps and I am wary of being "trapped" (heh) by the choices I make now!

I actually went out and bought a measurement mic but I cant seem to make the damn thing talk to the REW! I figured It cant hurt putting up large broadband traps 'blindly' though I can see a professional might take some issue with this approach...
intrancewetrust
Posts: 5
Joined: Sat Apr 18, 2020 11:22 am
Location: Tasmania, AU

Re: Reinforce or treat front wall (or both)

Post by intrancewetrust »

So i have done some more research and realised im using the term soffit completely wrong. whups. I suppose while *flush mounting* the monitors is ideal. I have two main concerns... I dont have my "final monitors" yet, or even know what they might be, and I may very well be moving in 1-2 years so I want to avoid that sort of rigid construction that cant be recycled/relocated. So I am trying to "half ass it as well as possible" I suppose, putting up lots of broadband polyester treatment that can easily be removed and relocated if I need to. The stuff I purchased is very thick and durable, it will even serve double duty by being a fine material to pad and protect my possessions in a shipping container when I need to move everything, and I can just put them up at the new house without fuss!

There is one rear corner that has a door so it cant have a bulky chunk of broadband treatment in it, I will probably use that area to make a targeted treatment like some panels or limp mass, after I have crammed the rest of the place with polyester and played around with the position of things a bit and figured out how to take a measurement.

I guess I should have put up a visual aid for my room dimensions, I described it in another thread but its probably more useful here too? It is a bit of a strange shape. I should probably mention, I am not an audio professional in any capacity, nobody is paying me anything for the time I spend in this room and nobody will be paying me to use the space ever so I am not expecting or requiring a professional level room, and didnt really expect to get that level of advice from an internet forum to be honest! Its great that people with that level of knowledge donate their time to strangers, and I dont want to seem ungrateful or dismissive of any advice donated to my cause! The truth is that if the room response was critical I would have invested in professional advice from the start.

In my case I just want an audible improvement for a fairly modest budget (~2k), and for the treatments to be of a light construction that can easily be removed and relocated. I am already over budget so I am somewhat limited in how I proceed. There are also numerous, lets call them "domestic concerns" that arise from using one bedroom in a three bedroom house inhabited by myself and my wife, the room needs to be a nice place to live and have space to move around etc. The room gets used for a lot of things, from music production and DJ sessions down one end, to mixing and general computer usage and listening down the other end, and even an impromptu discotheque when the visitors require it! My dogs will randomly do zoomies or have punch ups in here too :) So some speaker placements are just not going to work, placing them far away from the wall creates more issues for me that it solves in essence.

If that has you pulling out your hair with frustration I wont tell you that I have another room that is as far as I can tell as close to perfect as you would get in a bedroom for acoustics! If I was really chasing the perfect response it would have been a smarter move to setup in there, but domestic concerns are a thing, that room is nice and warm and quiet so we use it as our bedroom during the winter months and I am not really keen to sacrifice my winter comfort for my audio pursuits.

So basically I appreciate the advice but I dont think I can actually follow through with those suggestions, and I dont expect anyone to provide a professional consultation for free either!

I have decided to treat the whole front wall, theres a layer of 50mm fluffy on it now, and the corners are stacked with triangular offcuts of fluffy with a 600mm hypotenuse. These were basically scrap from cutting the other fluffy to fit the big corner trap. I have two big sheets of acoustic polyester left, I am cutting them so they will take up the whole front wall, and scoring them at the 2/3 mark so they will sort of "fold" into place creating 150mm of treatment for the mid 1600mm of the wall, and the remaining edges will be folded out to create full height corner traps.

I have attached some pics! Thanks
room copy.jpg
IMG_0215 lores.jpg
IMG_0253 lkores.jpg
Post Reply