BroadBand Bass Trap's Build

**cinema mad** · **01-25-09, 06:25 AM**

Yes A very handy piece of gear but very messy

and very very Dangerous like all planers.....

FWIW That Ryobi Surface planer was made in 1995 when Ryobi was OK but all the new Ryobi stuff is mostly rubbish now IMO, Disposable power tools ......

Cheers....

**Prof.** · **01-25-09, 05:06 PM**

"They don't make 'em like they used to"..

**robbo266317** · **01-27-09, 06:04 AM**

Unfortunately it's not just Ryobi.
I have a mate who repairs power tools and he recommends buying old tools >10yo and repairing them.
You name the brand & there is a 90% chance it isn't made to last more than its warranty plus 1 day.
There are still a few good ones out there if you look hard enough! and are willing to pay.

Personally I hate the fact that the rest are just going to end up as toxic landfill..........
my 2c

**cinema mad** · **01-27-09, 08:39 AM**

Yes I agree with your mate as far as the older Ryobi stuff being good quality, But The problem being that A lot of the parts for 10y + Ryobi power tools are No Longer Available Thus can't be repaired unless you custom make the parts needed...

FWIW I to used to Repair all heavy industrial and power Tools inc Electrical rewinds IE: Remanufacturing/ Rewinding Armatures, Stators and more in house for over 10 years....

Unfortunatly these cheap Chinese manufactured power tools are now disposable items, It costs more to repair these tools than replace which is what Ryobi/ Black&Decker (dewalt), to name A few do for warranty claims

....

Cheers....

**cinema mad** · **01-31-09, 05:20 AM**

I have finnished making my larger 4ft flutter Echo Diffusors 8 in total 4 per side, Just need to stain the frames and put the gloss coat on the Diffusors and frame.....
More to come....

Cheers...

**Prof.** · **01-31-09, 04:40 PM**

They're going to look pretty cool when their set up in you room!!

**cinema mad** · **02-01-09, 01:10 AM**

Yes Prof I am hopping they will look good, But as noted they are A nightmare to make...

FWIW I have been talking to Doug Plumb of Acoustisoft.com about the Excellent RplusD Room Acoustic measurement software (Ethan of real traps uses it) so I can optimize my room Acoustics, this includes speaker placement, EQ Subwoofers and "Room treatment placement" & much more....

I am going to "cheat" and use his 1 on 1 Consultation package, I figure that it would be better to use his knowledge & Expertise for the best result rather than me having to learn how to analyze & interpret what the Data is telling me + I am A very impatient

person when it comes to this stuff so that works against me also...

Has any one here used this High End room Acoustic software ?....

Cheers....

**fredk** · **02-01-09, 02:10 PM**

This is an interesting thread. I have read it several times now.

What frequency range are you diffusing with these?

**cinema mad** · **02-01-09, 10:31 PM**

Hi Fred & thanks for your post

,

This type of QRD Diffusor's coefficient range is usefull between - 3500hz --- + 20000hz..
If you mount these Diffusors with A space and air cavity combined with Semi riged fiberglass, absorbtion below the Diffraction limit can be achieved.....

Because the Well depth is only small they can be placed closer to the listner which is the biggest plus as compared to QRD Diffusors with 6" deep or deeper wells....

The Down side to this Diffusor is its smaller Diffusive frequency range as compared to A BroadBand Diffusor such as the type I will build later down the track....

Cheers....

**fredk** · **02-02-09, 11:26 PM**

Thanks Jason. I suspected that it would be higher in frequency. I would like to try some diffusion at the first reflection points on the side walls and this looked like a possible candidate. I think that with the smaller wells, they could look quite elegant.

I need to go back and re-read that section of the Master Handbook.

**thewire** · **02-03-09, 12:17 AM**

I have textured walls if that counts.

**cinema mad** · **02-04-09, 09:44 AM**

Finnished 4 diffusors & frames 2x4ft & 2x3ft with 4 Flutter Echo tiles per frame...
They will be hung slightly angled down.. They are mounted from A peace of 25mm x 32mm hard wood screwed into the stud of the wall then the mount on the back of each frame is simply hung off it....But the Diffusor mount is not fixed in place on the back of frame untill I check were the wall studs are so I can determine exactly where to mount it to the back...

I will mount them tomorrow and post some pictures of them in place & now that I have Acoustisofts RplusD software I will be able to check the theatres acoustic performance & placement of my room treatments thus far

....

Cheers...

**cinema mad** · **02-05-09, 07:31 AM**

Couple of pictures of the Diffusor panels mounted Next to the left & right side Surround speakers next to the Rear corner BroadBand bass traps & first reflection point traps for the second row.. But will be Repositioned to suit the smaller Bipole surround speakers when in place....

Because this is only A 5.1 set up there will be Bipole surrounds placed between the first and second row of seats and the larger 3way mono pole surround speakers picture will be placed at the rear for A 7.1 setup and the new theatre seats for the back row will be placed 2' to 3' of the rear wall...

Note that where the smaller 3' diffusors have been placed is close to the recommended 52% from back wall placement position ...

Cheers....

**fredk** · **02-05-09, 03:37 PM**

They look really good mounted in place.

**Prof.** · **02-05-09, 05:09 PM**

Looking good Jason...
I'll be interested to hear your evaluation of their performance..

**thewire** · **02-11-09, 10:53 AM**

Quote:

Prof. wrote:

Looking good Jason...
I'll be interested to hear your evaluation of their performance..

+1. Have you tried clapping or having someone else clap to see if you hear the difference?

**Lonely Raven** · **02-11-09, 01:13 PM**

Jason, those look great!

I built something similar from MDF years ago, and I want to use them on the back wall to kill flutter echo...but many of the acoustic experts tell me I'm wasting my time with diffusion...that I should just put up a bunch of absorption and be done with it...

But I've always had my audio rooms built with lots of diffusion to give a very live sound, and then only used absorption to deal with trouble frequencies and the low end peaks and nulls.

Here is what I have currently (sold most of my diffusers just before I moved):

Mine are 4" deep, so they are a bit more broadband than yours, but they are also 60+lbs if I remember correctly. I'm doubting I'll be able to hang them on the wall the way I'd like to.

I'm really liking your builds and would love to copy them, though I don't have a router table. I may just have to use a table saw for similar results.

I'll be following this thread to see how you like the diffusion throughout your theater...I'm finishing up my first 7.1 setup, and stuck with the diffusion/absorption. Hopefully following your thread will help me figure out where I'm going to go from here.

Great thread by the way!

**cinema mad** · **02-11-09, 11:46 PM**

Hi Lonely Raven & thanks for your post,

Wow Your QRD Diffusors look great

, Have you ever used them??

The reason I used A shallow well QRD design is because of the close facinity of the seating, the deeper the well of A QRD Diffusor the further away you should sit to alow optimum Diffusing performance...

Yes I have heard the same type of comments from A couple of Acoustic experts, I think it goes without saying that Absorbtion will give the most noticable improvement to A point but both Absorbtion & Diffusion are just as important in obtaining A well balanced lively ambient sound..

The problem is Knowing what Types of diffusors/Absorbers will work best given the room you are trying to treat inc seating positions in accomplishing A good result...
Although there is A general rule of thumb for Absorbtion placement areas I think Room Acoustic software is A overlooked & vital part of the equation in helping to get A well balanced sound ....

FWIW I am playing with Acoustisoft's RplusD software at the moment and having Doug Plumb perform A consultation...

More Diffusors to come stay tuned: next Skyline Diffusor

Cheers....

**Lonely Raven** · **02-12-09, 12:56 AM**

I have used those diffusers a little. I used them between my main speakers when I was doing two channel listening. I also used several larger QRDs built from the Decware plans along the side walls. I never got enough made to do any on the back wall of my listening room, and wound up selling all but these two units before I moved.

I really enjoyed the live sound of a bunch of QRDs. I had enough to give the discs I listened to added reverb...some may think too much.

Which makes me wonder how it's going to work for you, with 7.1 speakers all throwing sound into diffusers...

**cinema mad** · **02-12-09, 07:18 AM**

At the moment I only have A 5.1 set up so the Diffusors work fine but I will soon Mount some Dipole surounds on the Sides and move the 3way Mono poles to the rear for 7.1, then I will have to reposition the Flutter Echo Diffusors on the back wall or something as I know they cant stay near those Diples

...

Cheers....

**cinema mad** · **02-22-09, 08:46 AM**

Couple pictures of 4ft'r QRD with hight udjustable stands...

Cheers....

**Lonely Raven** · **02-22-09, 01:19 PM**

I'm following closely in your footsteps, CM!

I couldn't sleep last night, so I started working on these.

I'm recycling some American Oak stair treads that have been in storage for the past 13 years. They happened to be the same thickness as the design that inspired mine, so I worked from those measurements.

Unfortunately, just as I was cruising through the deepest cuts, the motor failed on my table saw! I can't afford this right now! I'm hoping I can figure out how to fix it myself.

When/If I ever get these done (I have four of them I'm working on now for the back wall), I'll be staining them in a deep cherry color to match the trim I've still yet to install. LOL

**cinema mad** · **02-22-09, 07:32 PM**

Wow they look good so far Raven, I think staining them as aposed to painting is the best option Especialy with hard wood. Deep Cheery will look Awesome...

What happend to your saw

that is an induction motor & are usually very reliable,
Does The motor Hummmm or did smoke come out of the capasitor cover on top of the motor, because it could be the Start/run capasitor which is an easy fix...

Its A pitty I am across the pond or I would fix it for you, but if you discribe what it did before it stopped may help....

Cheers....

**Lonely Raven** · **02-22-09, 07:43 PM**

Quote:

cinema mad wrote:

Wow they look good so far Raven, I think staining them as aposed to painting is the best option Especialy with hard wood. Deep Cheery will look Awesome...

What happend to your saw

that is an induction motor & are usually very reliable,
Does The motor Hummmm or did smoke come out of the capasitor cover on top of the motor, because it could be the Start/run capasitor which is an easy fix...

Its A pitty I am across the pond or I would fix it for you, but if you discribe what it did before it stopped may help....

Cheers....

The motor was having trouble spinning and popped the breaker. I took it all down (belt drive) and found it was *not* the arbor, belt, angle, or tension...so I started looking at the motor. It's a combination of things I feel. The bearing felt tight rather than smooth, the armature looks like it was rubbing a bit, I believe I did see a little smoke from the cap...and the little plastic looking disc that I believe the current passes through (not sure how but a copper leaf rides on this bakelite looking disc) is cracked and broken.

I'm attempting to clean and lub the bearings, and epoxy the backside of this disc...but if it passes current the way it looks, then I'm betting it's no go. If all that works, I'll track down a new capaciter. At this point, I should probably just track down a new motor. I just really can't afford this right now...so I'm kinda stuck on all projects till I can get the table saw spinning again.

**cinema mad** · **02-22-09, 10:37 PM**

The bearings should'nt be tight at all and can lead to issues, It sounds like the Rotor (armature) was poling (rubbing on the stator)... The little Slip ring on the front of the Rotor is only used for Start up it basiclly Engages & disengages the start cap for higher start-up torque it works on centrifugal force, once the motor is spinning at A certain RPM the slip ring disengages the start cap...

Cheers Lonely Raven...

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