BroadBand Bass Trap's Build

[cinema mad]

I just finnished making and mounting for now A small BroadBand Ceiling mounted Trap for the Treatment of first reflection Point's, I will be making one lage BroadBand Trap for the Ceiling the size will be 2" 2400x800 W.. And more for the Side Walls, and Screen Wall will be treated with 2" Semi rigid fiberglass as well But I need to get more 1200x2400 sheets of Semi Rigid Fiberglass (CSR BradFord UltraTel)... I have already used 5 1200x2400 sheets of Ultratel

The BroadBand Trap for the first reflection points on the Ceiling for now is 2" thick 1200x750 Ultratel with A 3" air gap.. The BroadBand Traps to treat the First Reflection Points for side Wall's Will be 2" thick with A 2" to 3" air gap same as the one on the Ceiling....

I made the Frames with 42mm wide x 19mm thick Pine.. For Ceiling mounting the Trap I used Eye Screws 4mm OD X 40mm L screwed into each corner of the trap... Picture Hanging Wire 12Kg Strength for holding the trap 2" to 3" away from the Ceiling...
For Mounting the BroadBand Trap For the First Reflective Points I used Threaded Plastic Plaster inserts that I then Screwed more Eye Screws into...

I used The Mirror Technique to find the First reflection point of the front Main and Center Speakers to allow the correct Positioning of the Ceiling Trap's ....

After I finnish treating my Theatre with absorbers I am going to build custom accoustic WideBand Diffusor's IE, RPG's Diffractal DFR73, Diffraction-Grating Diffusors or something simpler like Primitive Root Diffuser's to be placed on the rear, side walls and rear wall, to further refine the sound quality in the room and help with my pacific ROOM MODES combined with BroadBand bass traps/ BroadBand Traps will treat the lower and higher frequency room modes....





















Hope this Gives you some Ideas for your own Build Cheers....

[Prof.]

Very nice work Jason....All those panels should help things considerably..

I used 70x19 pine ripped down to 55x19 for my frames, for the 2" Supertel..because mine are mounted directly onto the walls and I wanted a flat surface on the fronts of them..

What would we do without our Irwin clamps eh!! they're a great bit of gear..

I've used more "Wall-Mates" in my theatre than I can remember..I've even used them for the ceiling mounted projector..
I also found they work well for mounting the side surrounds, just using an eye screw and a right angle cup hook..
My surrounds weigh about 10Kg...and they hold very well..

Keep us up to date with your progress..

[cinema mad]

Hi Prof,
Yes the plaster inserts "Wall-Mates" are fantastic and provide A very strong anchor in plaster for many applications, It sounds like you have found many uses for them Prof ...

I should point out The 42mm x 19mm pine used for the frame is perfectly flush at the front with the Fiberglass due to the double layer of Acoustic cloth's tension but the fiberglass is around 8mm higher than the pine frame at the rear of the BroadBand Trap But the Muslin hides this....

Cheers....

[cinema mad]

Thought I would share my DIY Tuned Bass Trap Build... Note This Bass trap is usfull if you dont want to absorb High Frequency's but reflect Thus it is not A BroadBand trap and is aimed for lower frequency's absorbtion...

Just Finnished My first reflection for side walls x4 4'x2' and 2x 8'x2' & 1x 4'x2' for ceiling
I also built another bass trap with high frequency reflection Membrane to go between the corner BroadBand Bass Traps in the back of the room , It will go where the back wall and ceiling meet for added low frequency absorbtion performence.

I chose to use A tuned Bass Trap to stop high frequency absorbtion as I didnt want the room to dead...
Next I will be adding Diffusion to the room, I am going with three types...

1/ Advanced BroadBand QRD Based Nested Diffusing fractal 2'x4', 2x will be placed inbetween the first reflection absorbers on the side walls...
2/ Primitive Root Diffusors 3-7" Deep for rear side walls...
3/ Diffusing tiles placed on ceiling aimed at flutter echos, 25mm thick...

So far it took me two hours to calculate/design then test make 1 flutter echo tile from MDF but I need to use hard wood as the well gaps are very close together and when routing the wells, the MDF would split .... See close up picture of Diffusor Tile Prototype for Flutter Echo issue's

Any comments and suggestions are most welcome Cheers...

[Prof.]

Wow!! jason..you're really giving it the treatment!!

I wouldn't be overly concerned about it being too dead..
I thought the same thing when I started adding treatments to my room..and even trhough you can hear the deadness ( for want of a better description ) when I walk from the outside room into the theatre, it still sounds alive with sound when playing a movie..

cinema mad wrote:

3/ Diffusing tiles placed on ceiling aimed at flutter echos, 25mm thick...

What size are these diffusion tiles you're making, and how much of the ceiling area are you covering with them?
If they're are made from timber, wouldn't they tend to reflect rather than absorb sound?

[cinema mad]

Hi Prof Merry Xmas and happy new year...
My biggest concern is being surrounded with posinous Fiberglass
As far as the Diffusion Tiles I can make them as long as I want but the well sequance is 4" wide total, so I can make them 4" /8' /12" and so on but you have to stay within the mathamatical formula..
They are Diffusors disigned to deal with fluter Echo in the higher frequency's but I can also mount with an air gap & add fiberglass behined them to absorb the lower frequencys....

So they will reflect in the lower frequencys if I dont design them to absorb the lower frequency's and they Diffuse not reflect in the higher frequencys...

The 2'x4' BroadBand nested diffusors are the most complexed ones I will be building but also the best performance....
Retail they are over $2000AU each in Australia for simlar design performance But you should'nt be seated any closer than 6ft from them for Best performance because of the Well depth I will be using....

Cheers....

[Prof.]

Thanks Jason and all the best for the new year..

cinema mad wrote:

The 2'x4' BroadBand nested diffusors are the most complexed ones I will be building but also the best performance....
Retail they are over $2000AU each in Australia for simlar design performance But you should'nt be seated any closer than 6ft from them for Best performance because of the Well depth I will be using....

Cheers....

I'll be very interested to hear your results on all these panels..and some pics during the build would be great..

[cinema mad]

I Made up some Acoustic Diffusing Tiles for the control of Flutter Echo, The design of these Tiles are Built using the quadratic residue sequence and based on A Prime 7 well 1-Dimention QRD Reflection phase grating principle....with the seventh well being formed when two tiles are placed beside each other....

As mentioned above I tried MDF but it kept splitting so I went with A hard wood "Tasman Oak" and had success...They are not that easy to make very very time consuming and A router bench with high quality router bits is A must for A clean precise finnish....
I am not sure wether to stain them to bring out the beautiful grain or paint them black ...

So far I have only made around 10 tiles as A trial run the next lot I will make will be 3ft long made from Tasman Oak hard wood....

More to come, Let me know what you think so far....

Cheers...

[Prof.]

Very nice job Jason..
That looks like an awful lot of work!!..How many tiles did you say you're making?
I think they would look great stained and providing that it's fairly dark stain, you should have minimal light reflection from them..

[cinema mad]

Hi Prof, Yes your right that it is A lot of work in making these tiles But the main thing is that because the well depth is only small you are able to be seated closer to them unlike the primitive-root & nested QRD type Diffusors.... These tiles are the less complexed to make compared to the other Diffusors I will be making....

At this stage I am unsure exactly how many of the tiles I will make/need but most will be 3ft long as to cut down on the layout of each tile.... Once I do some more in room analysis with the "future" ETF acoustic mesurement software I will have more of an idea...

No work today to hot ment to be"37deg" here let alone where you are in SA "41deg", some places in SA are upto '43deg" today .....

Cheers....