All Acoustics related

If I have to pick, I’ll first focus on having the panels behind MLP. That area is very significant. Followed by having it at 90 degrees side wall MLP . Finally 45-55 degree on ceiling in front of the main speakers

This 3 locations will have the most impact IMO, don’t worry so much about the front wall, that is best when used with absorption . The rest of the area can come later. But the priority for me will be the 3 locations. Behind MLP, side, and front of speakers ceiling area

As for the height of the placement, ideally 60cm from ground all the way to height of 120, that means 2x 60cm or single 120cm placed 60cm from ground ,if there is option to go 180, that is better and finally 240 will be ultimate all the way to the ceiling. The effectiveness increases with surface area coverage.

The room is our No 1 enemy, whilst we are not able to get a perfect room, we can work on improving it. The evidence is there to be seen and heard . Be kind to it and it will return the favour . Of course there are WAF factor etc etc … if it’s dedicated room, no problem I suppose

This hybrid approach of BAD ply with the rockwool backing is quite something

But still cannot beat the smt wings diffusors :rofl:… No 1 diffusor that one

I have the same plan too but can’t pass the WAF so didn’t go ahead.

I see, same same… I dare not ask also… lol… let it be…

Loading soon… need to sand and clean and then it is ready to rock on Sunday !

Some work to be done this week. Really looking forward to it now

In the meantime, here is another video from Anthony grimani

Very good ! Must watch, I’ve actually learnt something nice yesterday watching the video

He talks about “scattering & randomness” and how these tiny broken up reflections makes the acoustic porous :sponge: absorbers work harder

Very good and easy to understand

On the grimani video above, zoom in to time stamp 31mins… this is why we always use absorption panel in the middle of the back wall, behind MLP, only then we flank them with SMT wings diffusor

Just exactly like how bro NGSK

And mine done previously

This combination, as shown in Grimani’s video 3 weeks ago, explains why we need to have absorption panels exactly behind MLP, the centre behind our heads

Starting the work soon.

The above is how it looks previously behind the acoustic transparent screen.

I added some black acoustic transparent fabric to look like this now

My work today… to improve it further

Notice the area circled in Blue? That area is using gypsum board, a much more reflective surface. This area will now be covered with velvet, the spare ones I have in the room.

It looks like tiny pieces above, to cover the reflective gypsum board, the binary amplitude diffusors( BAD) then goes on to the velvet fabric, with the fabric working as absorptive material and the diffusors breaking up reflections into tiny tiny reflections so the velvet can absorb midrange frequencies much more effectively

The intended target range is the vocals from 500-3khz

After which the black fabric acoustic transparent material will cover the BAD ply

Here is how it looks comparing velvet with black acoustic transparent material.

Whilst the velvet is very effective with absorption, the AT fabric allows sounds to pass through. To determine which type of material allows sound to pass through, all you need to do is blow on the fabric and see if air comes out from the other end. If it does, then u know these sort of fabric, will allow sound to pass through…

Quite simple logic …

More updates along the way…

Here is the pics of the before…

After cutting the velvet to work as absorption behind the BAD, we used a nail gun and nailed it straight to the gypsum board

Once that is done …

We used the black acoustic transparent fabric to wrap the BAD panels, this will work absorbing light from the PJ

We used staplers to staple the AT fabric , damn fast the work from Lee. The fabric used are leftovers from previous project, just nice

Next we went ahead and used the nail gun to mount it on the rest of the bass traps

Uploading: 6B5C3645-9DA2-424F-B421-D9ECB31C226F.jpeg… Uploading: AA1AA9AE-9255-4C9C-AF85-0D0FC3B97880.jpeg…

90degrees beside MLP , at the bottom bass trap, top SMT, very very Tok gong !

Surround left location, also 90degrees beside MLP flanked by SMT

Beside the front baffle wall, my minions love the new panels

Corner dihedral section behind the second stacked seatons pair

Panels towards kitchen area, locked and loaded

All done now ! Testing soon tonight , just finished dinner

Can’t wait… the system is already top notch now…

Quick updates on initial impression

As predicted and anticipated, the bass is a lot tighter and the higher frequencies decays longer, creating that spaciousness feeling

Immediately, songs from male vocals really stand out. Turns out the panels work well from about 500-1khz range. This particular range of frequencies really benefit with the Binary amplitude diffusors . There appears to be multiple layers of instruments and u can distinguish clearly plucking of the guitar strings, very pleasant detail . Precision wise, it’s all there.

The letter R is very pronounced, each time it comes on from the Korean songs. Male singer.

I haven’t tested ULF… I believe there will be benefit here too…

At the stage I’m in now, it is highly possible to achieve fast And tight ULF

Overall, Lee was very professional, he went the extra mile and did a great job. Highly recommended . He is really fast, neat and detailed

I’ll be adding 2 more small pieces to finish the job. Might as well just complete it once and for all.


Circled in red to wrap it up.

Next up it will be bro NGSK room …

Turns out the CNC machine is hot , it needs time to cool too … just see the video below on how difficult it is if we had to do it manually

Lee is really good, wish I know him earlier. The bass trap he built for me was impeccable.

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Indeed, neat and nice . Speaking of which, in case anyone wants to know how he mounted it

Here is a close up, circled in blue. It secures onto the bass trap wooden frame. u can hardly see the nails.

Best thing is his price is very very reasonable, we cannot get this type of pricing… really good. And I don’t mind supporting him.

He is very appreciative I share this information on the forum, good for his business actually and I also dare to recommend his services, No fuss type. Patient and very understanding also :+1:t2:

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One very important point I forgot to add…

Whenever adding a diffusor, in the room or especially in living room, when you have finally gotten that approval, you wanna make it worth while and effective.

DONT USE diffusors made from foam , styrofoam, polyethylene foam , plastic, glass or cardboard etc. They are not your friends for sound. If u use that, what follows is the direct sound + the sound redirected off that particular material.

Foams should never be used in my opinion, they do more harm than good . Foams like this at the bottom should be avoided as they absorb the high frequencies and suck out the energy in the room whilst doing nothing at all to lower frequencies in the bass region

Instead, use a proper panel, for absorption, rockwool or mineral wool with lower density to allow for air flow resistivity with air gap. that is what we want

For the upper range of frequencies, always go with wood material for diffusors , they make a lot of difference when you have enough surface area covered

All these if placed in an ideal spot, ideal material , hybrid diffuse absorb can make a big difference . What most of us will really like is a faster decay at lower frequencies and an extended decay at upper high frequencies

Between that extended redirected energy , using the BAD ply version disperses energy in all directions , like the one below

They are ideal, when placed at height locations

The SMT Wings however , disperses energy in the lateral position, like this below… resulting in an extended decay in higher frequencies , that is why the SMTs are placed 60cm from ground

One more important thing I forgot to add as well. If the intention is to use the bass traps with a scattering plate like the binary amplitude diffusor, a bevel like this will help

Or chamfered edges. This should help with edge diffraction problems for a smoother scattered energy distribution when the traps behind has chamfers like the above

A sample of the bass traps with chamfers/bevel

Observe the edges around it has some chamfers

A 45 degree chamfer is a good starting point and looks aesthetically pleasant too

In the sample below , there is no need for chamfers if the ply is mounted onto the bass trap circled in red, although the scatter will be moving in the lateral position, the SMTs flanking then will take care of it …

A bevel bass traps if having a ply should help

Or another like this , sample from universal studios

Curved version :muscle:t2::muscle:t2:

It seems like metal sheet is used for the curved version, right?

It does look like metal in the picture , but I’ve not really seen a metal based diffusors, honestly I’m not sure what material they have used…

All I know is we want soft wood material for diffusion … those should sound really good if the mathematical sequence is good

The mathematical sequence is way more important than the material being used…

So for maximum effect , we want soft wood material + good mathematical sequence in the diffusors . This combination, :muscle:t2::muscle:t2::muscle:t2: Power !

The way we place it and it’s location also makes a difference

Wrapping this up now for my place.

Overall very satisfied now with the sound quality of the room.

Next up is to help bro NGSK then hillviewer

Finally completed everything ! Nothing more to improve on

Mounted the two more pieces to finish it.

Also took the opportunity to fine tune the centre speaker placement t with proper isolation.

Using cork, followed by ikea chopping board with sorbothane , divini footer , speakers and finally stuffing the rest with foam to avoid any comb filtering

The addition of the BInary Amplitude Diffusors really brought up the tightness in upper bass frequencies.

Male vocals and bass from instruments sounded a lot lot tighter, especially watching and listening to the same material and music again. It’s quite pleasant.

Whilst the divini PTY power cord brought out the best in female vocals , the BAD is fantastic for male vocals.

I like how they supplement each other in the set up.

Even my 7 year olds boy was telling me, daddy how come this song sounds so nice at home ? I can feel the sound bouncing… so special… we were just playing a simple Song from YouTube by IU, title celebrity . Then the 9 YR old girl said, the system sound so good, why do u keep changing things ? :rofl:. Then as usual the mummy chimes in and said, “Jiak Pa bo Shu zho!” Hahahah… so I said ok ok no more touching… lol

Spot on man, the bass effects are bouncy and really pleasant sounding . However, I didn’t really get any improvements whatsoever in decay and extension of female vocals and sense of Airiness. They sounded the same…

The only time I felt that extension was when the SMT wings diffusors were being used in the room

Last night I confirmed it again at my place, very interesting stuff

So yesterday Mr Lee popped by to finish the job, installing the two panels in red.

Two weeks ago it was the panels in green.

The ones installed on the location highlighted in green, didn’t really improve the bass as much as when the BAD panels were installed in the location at the red circled area!

What a big difference it made. I was scratching my head pondering why that is the case ? Then I realised 1 thing.

When the line array woofers are lined up left and right, a lot of the concentration of velocity energy moves through the middle, forming the stereo image in centre

This is where the panels circled in red comes into play

But behind my MLP, there is no absorption, instead I went with the stack subwoofer placement

What was once a situation where co-located subs were placed at the bottom, with the absorption panel above that (like the below) position, is now no longer having any absorption in the middle , where a lot of the velocity energy are headed towards

Notice the above is my previous arrangement, they were effective placing it this way

So killing off the velocity energy at the opposing centre wall somehow helped. Even with the slightest of surface area covered

That explains why the bass at 300-800hz ish were sounding a lot tighter.

The conclusion I have from this upgrade is that you can never get enough of tightness when it comes to bass. The tightness has improved significantly when all the surfaces are covered with the bad ply .

The impact of scattering and breaking down the energy for the panels behind it to absorb that breakdown in energy is working wonders. For the first time I feel that the bass traps are really being fully utilised to its max potential

When the energy is broken down into tiny reflections, the bass traps behind it works harder as they now have more surface area to cover

In conclusion, apart from quality of the material used, quantity does matter ! More is better ! No doubt about it

Ok let’s go in deeper now. Assuming I am new and I want the best for my room. What types of diffusors or bass traps should I use ? There are 1001 panels out there.

Again we cannot stop anyone from hanging anything they want in their rooms. That’s their room, their $, their choice for treatment, their call, as $$ also plays a part.

But what I can share is that, a good quality diffusor, makes a hell lot of difference to the set up.

If you had just bought one from China/India, from an unknown source, say something like the above ,

u might want to pause, and do a bit of a research, and probably ditch it for a quality one. Or if u haven’t got any, make sure you do a thorough research, or even if u decide to diy, make sure you get the mathematical calculations correct

Or even this below, a polyfoam skyline diffusor

image

U wanna make sure it really is effective, before hanging it onto the walls. Remember space is precious, when u hang the above, u no longer have space to hang another absorption or diffusor

Now, having used both the SMT wings, and the bass traps with BAD in front. I must say they both function differently, very different.

In dialing in the system, I always like to maintain a specific pattern of consistency . Maybe that’s how we have been trained, consistency being either you are consistently wrong, or consistently correct. We don’t have a situation where we put in a debit, but not a credit. It’s only one way, either the debit credit is correct or the debit credit is wrong.

Anyway, back to subject. That’s how I like to do it, consistency. And they work wonders indeed. When we approach the room acoustics, what we want to achieve is a consistent decay, be it in the lower frequencies or upper frequencies.

Although we are working to improve the decay times in the lower octave to 0.2 to 0.3ms , we want the decays extended at the higher frequencies to take advantage of the physchoacoustics where our brain interprets the room as “bigger” or more “spacious” . A consistent “reducing decay times” from 20-200hz, is very pleasant sounding indeed. Similarly, a consistently “extended decay time” in the upper frequencies, makes it very pleasant , about 40ms extension is really pleasant especially for stereo. This also suggests why a lot of the high end rooms are fitted with mostly diffusors . Quality ones

So ya, if I was to recommend, I would highly recommend confidently to go For the SMT wings. As far as my testing goes, this is one of the best acoustic diffusors one can get, it’s calculated, proven to be effective. No horse run indeed

The bass traps with BAD ply, cannot give me that type of extended high, liveliness and extended decays in the upper frequencies where stereo can be very pleasant . They were instead, more effective with the upper bass frequencies only

And the answer is yes, we need at least a few SMT quality like diffusors, or equivalent in our room, especially for stereo, the stage, airiness, space, it’s just unbeatable. They really bring the entire system up to another level.

A hybrid approach, absorption- diffusion, is really the way to go. They supplement each other well.

If you are still using foams like this below,

My advise, really is Ditch it ! Oh boy… hope I’ve not started another war…


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