Martini Absorb HD100 on walls

[drummerboy01]

Picked up some Martini Absorb and got to work on my walls in my dedicated theatre room. Huge difference in sound compared to untreated. This stuff is great in price. It came in sheets of 2.4x1.2 so i cut them up into 1.2 x .600 panels and it did the trick. Have the option of framing them down the track but it looks good as is. The NRC rating on these panels are 1.00 which is great for me as my room is already lined with 2 layers of Boral 13mm sound stop on walls and ceilings.Will get some 50mm Martini next year and do the ceiling. Night and day difference. Purchased this through CSR direct. 

[Steffen]

Congratulations, I'm not surprised that it makes a massive difference. How did you get around the minimum order quantities they usually impose? I've never been able to get a quote for less than $700-800 or so plus shipping, when all I needed was a single 2.4x1.2 slab.

[drummerboy01]

Hi Steffen,My plan is to do the whole room so 1 or two sheets were never an issue for me to begin with. It was better for me to buy 2 packs. I priced Auralex product and what they were offering was no where near the amount of absorption as the Martini and would of paid double the price of the Martini. I have an account with csr and got 2 packs for a total of 6 sheets for less than $630.00. The minimum order was never an issue unless I was to only need the amount you specified so there was nothing to get round for me. I was told they need to make the sheets as you order so the only way to get round that is if they change the system and stock them in places like Bunnings. The good news is, that it could be a possibility in the future. Maybe it’s not called for that much in the residential market compared to the industrial market where big orders are needed anyway. If the pros in the music industry get involved then things could change but they rely on other brands because it’s been handed down in their industry for many years thinking its the best or what they must buy.Martini Absorb is a brilliant product for the money and I would not go any other route at least for now. Cheers mate

[b0dhi]

Looks great, OP. I wanted to use these panels for my studio too but I too wasn't able to get them in small quantity, especially the black colour which nobody stocks.

[drummerboy01]

Thanks mate. The difference in sound is night and day. The missus is happy too, early xmas present. We fired up San Andreas and the martini absorb made me appreciate atmos a little more. Basically the Martini absorb was the missing link in my home theatre room.

[Irek]

Looks awesome. 

[drummerboy01]

Thank you Irek. We had fun installing it. Great thing about this product is it’s non itchy being a polyester fibre. We are rapt with the results mate.

[iversons13]

Good job. Curious what method you used to cut it?

[drummerboy01]

16 hours ago, iversons13 said:

Good job. Curious what method you used to cut it?

I used a nicely sharpened kitchen knife. The sharper the better. I tried a hand saw and it cut it but no where near as neat as a sharp knife. The blade itself was 200mm long for cutting 100mm thick Martini. Again, it needs to be sharp for a nice cut. After every 2 or 3 panels that I cut,I sharpened the knife. I tried an electric kitchen knife and got nowhere with it.It basically needs to be sliced NOT back and forth.Hope this helps

[:) Go Away (:]

How did you hang them on wall?

 

I have recently got some HD50mm sheets and find it not as rigid as I hoped. They do stay upright when I place them on wall, so shouldn't be an issue there. But what material did you use to stick them up on wall?

 

Previously, I had bought some Woven Image's Acoustic pin boards in 12mm and they are very rigid and all I did was to screw them on strip of wood at top and bottom and used 3m double sided tape to hang on wall. 

 

But these martini absorb 50mm is more fluffy than rigid. I really would not prefer to make a frame for them.

[blybo]

13 hours ago, bluehalk said:

How did you hang them on wall?

I'd like to know as well. I have twelve 1200x600x50 panels and have simply double stacked them in corners and on a 45 degree angle below the screen. I'd love to get a neater finish and they do topple over occasionally.

[drummerboy01]

Hi guys, I am really really sorry for the late reply as I have been away working. On my 100mm Hd there is a soft side and a rigid side. The rigid side according to the Martini absorb Rep should face towards you when hung.I used extra heavy duty Velcro stuck on the soft side. I cut 5 velcro strips at 100mm in length and stuck them on the walls4 on each corner and 1 in the middle and then hung the panel.  No frame needed. This stuff is great and my panels are still hanging. Again really SORRY for the late reply and did not mean to leave you guys waiting. Cheers.

Edited February 21, 2020 by drummerboy01

[oztheatre]

On 06/12/2019 at 1:21 PM, drummerboy01 said:

Picked up some Martini Absorb and got to work on my walls in my dedicated theatre room. Huge difference in sound compared to untreated. This stuff is great in price. It came in sheets of 2.4x1.2 so i cut them up into 1.2 x .600 panels and it did the trick. Have the option of framing them down the track but it looks good as is. The NRC rating on these panels are 1.00 which is great for me as my room is already lined with 2 layers of Boral 13mm sound stop on walls and ceilings.Will get some 50mm Martini next year and do the ceiling. Night and day difference. Purchased this through CSR direct. 

 

 

I_MUST_HAVE_STORMTROOPER - please tell me where you got that Alan? 

 

It's not the disney one is it? They were a bit smaller judging by that awesome looking screen you got there 

Got the vader disney one but no light sabre.. The skywalker and solo ones were bloody terrible, sideburns like elvis and solo got a huge snozz too.

 

[drummerboy01]

Hey Rich, hope your keeping well mate. Got them from BigW for around $300 a pair up here in Gladstone mall. They come with batteries and talk. Way better than Barbie and Ken.(hehe).They were on display as i walked into BigW and i could not resist. I don't know if they are disney or not as i did not plan on buying them or even did a search as i just got them off chance. The light sabre glows when turned on. The screen is fantastic mate. 

[super kermit]

Hi

 

From my research these panels are the way to go. I am thinking of encasing them in a wooden frame and then using a print on top as the home theatre is also the lounge and dining room all in one.

 

That way they can look like normal art/paintings but serve a purpose.

 

Sydney apartment living.

 

https://myfabricdesigns.com/

 

https://hdqwalls.com/

[DubbyMcDubs]

This material is a really great option. It performs well and is much nicer to work with than fiberglass. 

 

I have a lot of experience with it as I used  XHD 100 and XHD 50 in my HT.  To cut it, buy yourself a couple of packs of cheap stanley knife blades from bunnings and use those in your knife. The material dulls the blades quickly so you will just use until it stops cutting nicely and discard. That way you get a nice cut.

[almikel]

On 06/12/2019 at 1:21 PM, drummerboy01 said:

Picked up some Martini Absorb and got to work on my walls in my dedicated theatre room. Huge difference in sound compared to untreated. This stuff is great in price. It came in sheets of 2.4x1.2 so i cut them up into 1.2 x .600 panels and it did the trick. Have the option of framing them down the track but it looks good as is. The NRC rating on these panels are 1.00 which is great for me as my room is already lined with 2 layers of Boral 13mm sound stop on walls and ceilings...Night and day difference. 

Nice work  - IME room treatment makes a massive difference - "bang for buck" way more that most other upgrades with perhaps the exception of upgrading speakers.

 

On 06/12/2019 at 1:21 PM, drummerboy01 said:

Will get some 50mm Martini next year and do the ceiling.

I'd review your room reverb times before adding further absorption to the ceiling - you want to avoid absorbing "too" much top end.

 

Your reverb times (and waterfalls etc) will also show how well the room bass is being managed.

 

Really nice room - I'd love a listening/movie watching space like yours  

 

cheers

Mike

[wasabijim]

I'm sold 

cheers

I'll try CRS directly or try pull some favours with tradie mates who hopefully have an account already

[almikel]

6 hours ago, wasabijim said:

I'm sold 

cheers

I'll try CRS directly or try pull some favours with tradie mates who hopefully have an account already

Don't put it directly on walls

 

IMHO target treatment at lower frequencies first - go as big/wide/deep as you can get away with - always straddling corners to create an air gap to be more effective at lower frequencies.

If you want absorption to work low (say < 200Hz) it needs to be big/wide/deep/air gapped.

 

200mm deep/thick x 1m wide floor to ceiling straddling the 4 vertical wall/wall corners is the sort of size required for absorption to manage <200Hz...

...and that size is too small to be effective below 100Hz or so

 

Mike

[wasabijim]

thanks for tips

we should be moving into our new build in about 6 weeks. I was able to grab a bunch of perfectly fine left over HD fluffy batts and I plan to have a go at some top to bottom corner DIY "superchunk" traps, just the 2 behind speakers. then look into a worthwhile mic and software to get a measured baseline. I'm considering ceiling clouds and had the sparkie set it up so i can readily run some LED strips into the mix for effect. 

[almikel]

20 hours ago, wasabijim said:

I was able to grab a bunch of perfectly fine left over HD fluffy batts

what density?

HD (high density) and "fluffy" are contradictory terms

 

Standard "fluffy" batts have a density around 15-20kg/m^3, and a Gas Flow Resistivity around 5000 Rayls

Polymax XHD is around 48kg/m^3, and a Gas Flow Resistivity around 12000 Rayls.

"HD" batts would be somewhere in between - if you know the brand you may be able to track down the Gas Flow Resistivity on the interweb - Gearslutz and Bob Gold's site have some useful information, but more focused on the US market.

 

The Gas Flow Resistivity is handy if you want to model the absorption using tools like this http://www.acousticmodelling.com/porous.php

 

The higher the gas flow resistivity, the more important to have an air gap - and playing with different thicknesses/air gaps/gas flow resistivity in the porous absorber calculator will give you a feel on what happens to room absorption, especially effectiveness down low, as you change the parameters.

Here's 100mm Polymax XHD on wall vs 200mm air gap - it's very clear you shouldn't place expensive Polymax XHD on walls!

 

Fluffy is much cheaper than Polymax XHD, so here's a comparison between 300mm of fluffy on wall vs the same gapped Polymax XHD as above (100mm XHD/200mm gap) taking up the same room real estate - the fluffy performs better.

 

Unfortunately I've never found a modelling tool that models for the triangular air gap behind corner straddling absorption traps

 

As you can see absorption has reducing effectiveness down low - to trap bass they need to be large and deep.

Even with fluffy there's benefit in an air gap - here's the same thickness of fluffy (300mm) on wall vs 100mm air gap (so more room real estate consumed with the 100mm air gap)

 

I may have said this above, but the reason absorption works better down low with air gaps is that absorption traps work on slowing down air particle velocity - absorption works best when placed where the air particle velocity is highest.

Air particle velocity is theoretically zero on a boundary, and highest at 1/4 wavelength from a boundary.

When you do the maths, @ 100Hz the wavelength is 3.43m and 1/4 wavelength where the velocity is maximum (ie where absorption is best placed for maximum absorption) is 0.86m off the boundary!

Not many people have that much room real estate to give up to absorption room treatment!

 

The good news is that absorption still works as long as velocity is > 0 - hence air gaps help to place the absorption where velocity is increasing.

 

There are other more specialist traps that work on pressure rather than velocity, but that's another topic entirely.

 

IME with my lightly constructed room that let's a lot of the low bass leak out, decent sized absorption working down to 150Hz or so, with some bands of EQ cut below that,  works fine to manage my "in room" bass.

 

cheers

Mike

[wasabijim]

that's some pretty comprehensive subject matter. its not the first time I've tried wading into it but you've definitely added a degree of clarity without headache inducing statements (or opinions) - cheers.

another topic entirely indeed, and without hijacking the thread I'm really trying to find my own comfortable balance point, somewhere among - do nothing, subjectively just put stuff up, putting a worthwhile degree of thinking and objective measurement into it, or doing a master's degree in applied acoustic engineering.

 

Am I right that a take away is that the air gap is moving your absorption material towards a more effective point in the wave length. for the same room real estate/wave length point is the air gap better than more material? ie. 200mm+10mm air gap vs 300mm + no air gap? 

 

the fluffy stuff is a garden variety mix of R2.5 ceiling (Pink Batts) and R2.0 HD (something a rhino in the branding)

 

[wasabijim]

6 hours ago, wasabijim said:

 

 

Am I right that a take away is that the air gap is moving your absorption material towards a more effective point in the wave length. for the same room real estate/wave length point is the air gap better than more material? ie. 200mm+10mm air gap vs 300mm + no air gap? 

 

 

 

 i was able to play on the Acoustic Modelling  calculator and get an idea 

[almikel]

On 08/12/2020 at 9:23 AM, wasabijim said:

Am I right that a take away is that the air gap is moving your absorption material towards a more effective point in the wave length

correct.

As frequency drops, wavelength increases -> velocity (speed of sound 343m/s) = freq x wavelength

I don't have a formula for the air particle velocity which cycles from 0 on the boundary to maximum @ 1/4 wavelength to zero again at 1/2 wavelength etc, but it's based on a sine wave.

Pressure does the opposite, from maximum at the boundary to 0 @ 1/4 wavelength etc, based on the complementary cosine wave.

 

On 08/12/2020 at 3:31 PM, wasabijim said:

for the same room real estate/wave length point is the air gap better than more material? ie. 200mm+10mm air gap vs 300mm + no air gap? 

(my bold) No - the absorption just doesn't do much - if you're using expensive Polymax XHD, the material close to the wall doesn't provide much bang for buck.

If using fluffy, it doesn't matter so much as it's less expensive - filling the gap is OK, unless you have another corner you could "straddle" with an air gap that would otherwise go untreated.

If you have "permission" to treat only the 2 vertical room corners behind the speakers, a reasonable approach might be to use say 100mm deep/1200mm wide polymax XHD from floor to ceiling, straddling the corner, and fill the gap behind with fluffy.

 

I wouldn't "fill the gap" with Polymax XHD - I'd try to convince the boss that another room corner was treated - and below the transition point in your room (around 250-300Hz), room resonant/modal behaviour dominates - so it doesn't matter much which corner you straddle for absorbing bass in your room...keep in mind wall/ceiling corners which don't take up floor space (just more tricky to mount)...

...There are 20 corners in a room - 8 tri-corners, 4 wall/wall corners, 4 wall/ceiling corners, 4 wall/floor corners

 

cheers

Mike

[almikel]

On 08/12/2020 at 9:23 AM, wasabijim said:

the fluffy stuff is a garden variety mix of R2.5 ceiling (Pink Batts) and R2.0 HD (something a rhino in the branding)

if combining both into 1 trap, put the denser stuff further from the walls.

 

The same porous absorber calculator can model multi layer, limp mass and helmholtz traps - just click the calculator icon to see a drop down to select

 

Off topic - but I'm constantly amazed and impressed with the quality of the audio tools that developers provide for free on the internet such as this one, REW, HornResp, QRDude, Multi Sub Optimizer etc - huge gratitude 

 

Below I modelled:

• 300mm Polymax XHD on wall (blue)
• 100mm Polymax XHD 200mm air gap (green)
• 100mm Polymax XHD with 200mm fluffy "filling the gap" (red)

So same "room real estate" (300mm) consumed in each case

 

Keep in mind modelling tools don't tell all the story - they use lots of assumptions in their calculations, and shouldn't be treated as gospel - especially in the case of placing treatment straddling corners, where the air gap is variable, which the porous absorber calculator is not considering - with straddling corners the air gap decreases on the edges so low bass absorption would decrease.

 

My take-outs from the above - and I'd really appreciate @davewantsmoore's input - which may differ from mine, but he understands this stuff way better than I do - so I'm happy to defer to whatever Dave says as correct:

• start with speaker/listening position placement 1st - but IMO every room has an improvement with some absorption treatment targeted at lower frequencies
• most people would regard 300mm deep absorption traps as "fairly big/deep", and many wouldn't get away with having them in their room - but the porous absorber calculator shows absorption is below 0.8 @300Hz for blue and red and decreasing at lower frequencies - showing that absorption needs to be very large/deep to manage lower frequencies
• the swings/dips/peaks in absorption of the 100mm polymax with 200mm air gap (green curve) won't exist in real rooms - the models assume rigid walls...you should "smooth the peaks/dips in your head" for the something approaching the real world
• the same applies for the bump/peak in the green curve where it "appears" to perform better 100-400Hz than the other 2 scenarios...I don't think this will be the case in real rooms - ie I think they all would perform "similarly" in that range.
• the graphs show improved bass performance below 70-90Hz for the blue and red curves over the green curve - but we're way down across all the graphs - so don't expect much impact from any of these examples of treatment for room issues much below 200Hz or so unless they're huge - the modelling was done at 300mm deep, but the tool doesn't factor area
• to get reasonable room absorption down to 200Hz or so, absorption traps need to be big - large and deep and air gapped
• to get reasonable room absorption down to 150Hz or so you need more absorption traps and/or truly massive absorption traps
• realistically you can't treat room bass issues below 150Hz or so with absorption -  absorption needs to be too big (area/depth) to be practical
• with absorption deployed straddling corners - go as deep/wide/tall as you can get away with, and as many corners treated as you can get away with - you will significantly clean up >150Hz bouncing around your room (ie the top end of bass/lower mids)
• by deploying absorption in the corners, you'll be avoiding absorbing too much top end (higher frequency) 1st reflections - ie trying to not make your room "too dead" - but if during this process you've absorbed too much top end, there are ways to bring the top end back, but continue to absorb bass
• I would recommend acquiring a measurement rig during the process so you can measure results
• after applying absorption treatment you can address any remaining room bass issues <150Hz with speaker/listening position placement and/or EQ...or specialist "pressure" bass traps (eg Helmholtz/Limp Mass etc)...unfortunately "pressure" traps are tricky to design/implement, and need tuning to get right for your room

cheers

Mike

Edited December 9, 2020 by almikel