# Acoutical Diffuser construction advice



## Tonto1 (Nov 10, 2016)

Hey guys, my main interest is currently in Home Theater & I am in the process of building my own HT. I have the plans for the "Leanfusor," but not being an expert in wood working, I thought I would ask here for advice. Seems like a very nice forum (vertiscope owns Hometheatershack.com where I spend most of my time).

I guess I need advice on the best way to complete the build. Can't post links yet, but this is the URL. You should be able to copy it and paste it into your address bar. Let me know if it doesn't work.

arqen.com/wp-content/gallery/sound-diffusers/sound-diffuser-calage1-w700.jpg

I'm thinking I can build the endplates (maybe 2 more for along the length at intervals for stability). in the correct shape & attach 2"x4"'s to them I think I could router the 2"x4"s before attaching them, but I don't know if that is the best way to go about it. Thus the need for this thread.

I help people with time/money saving HT advice all the time, because I know so much about it. I figure you guys are the go to woodworking guru's so any advice on any equipment that I would need & the best way to go about it would be greatly appreciated.

Thanks in advance
Quenten


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## Cherryville Chuck (Sep 28, 2010)

Hi Quenten and welcome. Here is the working link http://arqen.com/wp-content/gallery/sound-diffusers/sound-diffuser-calage1-w700.jpg . The first example could easily be built in a few minutes on a table saw. I see you don't have one but it can be done a bit more slowly with a circ saw and a straightedge to guide it. Easiest but not the prettiest would be making it out of a sheet of plywood or mdf.

The second example is much more efficient as the illustration shows but would require a router. Even better if the router were mounted in a table but not absolutely necessary. The profiles can be done with beading bits. But there is an alternative to that too but a little more pricey. You could just buy ready made dowel rods and glue them to something resembling the first illustration. You can hold them in place with masking tape while the glue dries, maybe only a few pieces at a time. That would achieve the same effect as machining all those curves on individual pieces and gluing them together anyway as there is no other way to combine all those profiles.

Something in between the two would be much cheaper and much easier where you take the first profile and replace the flat strips added to the base pieces and replace them with dowels. You get rid of the hard flat edges that way. You could also cut dowels in half and do that which would be cheaper again and eliminate the traps that would be formed at the back sides of the dowels but you need a table saw for that.


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## Tonto1 (Nov 10, 2016)

Hey C-Chuck, thanks for the quick reply. I posted those pictures too fast this morning & didn't really mean that design. This is the one I am thinking about.

http://arqen.com/wp-content/media/acoustic-diffuser-fractal-588x315.jpg

Same dementions, no rounded tops! The problem is all those wells of different depths. This design should be a bit simpler. I was thinking I could use plywood & lumber for the basic design. That would be easy. I also thought the easiest plan would be 2x4's on top of the basic frame which I could router ahead of time. 
I hadn't considered using my Circular Saw with a guide. The Milwaukee would be fast and certainly has the power for the job (15 amps). Faster than a router, I don't know. There would be many cuts with the circular saw...unless there is a special blade for that purpose (cutting grooves). If there is, that would be ideal. But that is why I came here. I felt you guys no just about everything about tools & woodworking. I think I remember in high school seeing a table saw with a dado blade that cut grooves. Does that sound right? Anyway, this is the basic plan for 1 of the 7 panels which when completed would hang side by side on a French cleat. I'm thinking I would make them 6 ft long. These are the instructions he sent me. I have the depths of each well on another email. I will look them up. 




> Hi Quenten
> Everyone seems to love fractal diffusers, but to most of us they look ridiculously hard to build. I've tried to break it down for you with this modular fractal stepped diffuser.
> I'd like to introduce you to my favorite diffuser design: the Leanfracal. You may have seen it featured on the Arqen.com homepage, or read about it in my diffuser design thesis (where it's known as A1-Frac).
> 
> ...


I am open to all suggestions, but just like everybody, I'd like to consider the cheapest solution while maintaining quality.


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## Tonto1 (Nov 10, 2016)

Wow, I just typed a long reply, clicked post & it disappeared! I'm at work now, will see about rewriting it later. That's for the quick reply Cherryville Chuck!

The jist of it was:

1) Build the basic frame, router the groves in a 2x4 & glue/screw them on.
2) Use my Milwaukee to cut the grooves (is there a special blade the it could use to make wider cuts?
3) Would a table saw with a dado blade cut the grooves?

Thanks for all your advice.
Quenten


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## RainMan 2.0 (May 6, 2014)

Welcome to the forum Quenten  

I'm sorry I don't have any advice , but HT is one of my favorite subjects ,so I will be watching your build closely if you share it with us .

I know a guy that designs home theatre rooms in his new homes , and I know he mentioned the ceiling was not level in order to suppress standing waves . 
These diffusers your making seem a little differant from the way I'd approach it , but will be interested to see how you make out


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## Cherryville Chuck (Sep 28, 2010)

Ok Quenten, I fixed the link. First, that build is a layered build. The outside pieces are are attached to one piece of panel board. The middle part of the base has been built up with layers of something and I really don't recommend dimension lumber for this as it tends to warp, cup, and bow with changes in humidity and temperature. The individual profiled pieces are attached to that and it depends on the scale of the size as what they could or should be made of. Yes they can be profiled with a dado set on a saw. They could also be cut with a router and a straight bit with an edge guide on a router or on a router table but this method is slow and there is a lot of wear and tear on the router and bit. Best overall method is to use both. Get close with the table saw to remove the bulk of the waste and then finish with a light cut with a router to get a better finish. Depending of the size of the pieces you might also be able to build that from mouldings available at your local hardware store and then all you have to do is cut it to length. 

By the way, I have physics in my education and the 1/2 round dowels will do a better job of dispersal. The distribution pattern (reflection i.e.) will be almost totally random.


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## RainMan 2.0 (May 6, 2014)

Charles I thought the same thing . Not liking the idea of flat surfaces in the equation


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## tomp913 (Mar 7, 2014)

Half round molding should be relatively easy to find - Home Depot carries 1" x 1/2" x 12' long polystyrene molding as well as various sizes of wood half round.


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## old55 (Aug 11, 2013)

Welcome to the forum Quenten.


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## sunnybob (Apr 3, 2015)

Back when I was a HI Fi nut (60's to 90's), any wood surfaces were a complete no no. Thick carpet and curtains with fabric furniture was the answer. I knew several people who papered their walls with carpet tiles.


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## Cherryville Chuck (Sep 28, 2010)

Generally I agree with Bob. If you don't have all those acoustically dead surfaces in the room you start getting echoes which reach your ears at slightly slower speeds that the original wave and it can sound like crap. However, the old Bose 901 speakers were built with 8 speakers that faced the wall behind them and 1 speaker pointed directly at you. The 8 speakers facing the wall were meant to fill the room with sound by reflecting at many angles and the 1 facing was needed or it would sound like something was missing. I was also an audiophile during roughly the same years as Bob and I found the solution was 2 speakers directly in front pointed at you, usually with a minimum spread of about 2.5 metres and 2 speakers directly on either side of you pointed straight in.


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## sunnybob (Apr 3, 2015)

I never liked quad sound. When it first came in to the UK in the early 70's I knew a very rich man who spent a scary amount of money on the latest 4 speaker system. I went to listen to it. You had to sit in a particular chair in a particular spot to hear everything properly. Only 1 person in the room got the full effect,and to be honest, hearing stuff behind me just distracted me.

Surround sound also doesnt please me, i'm just a stereophonic kind of guy..
Now all my hi fi went several years ago and I live in a house with harsh bare walls and a tiled floor. Even the new TV sound is muddied bouncing off everything.
How times have changed.


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## RainMan 2.0 (May 6, 2014)

sunnybob said:


> I never liked quad sound. When it first came in to the UK in the early 70's I knew a very rich man who spent a scary amount of money on the latest 4 speaker system. I went to listen to it. You had to sit in a particular chair in a particular spot to hear everything properly. Only 1 person in the room got the full effect,and to be honest, hearing stuff behind me just distracted me.
> 
> Surround sound also doesnt please me, i'm just a stereophonic kind of guy..
> Now all my hi fi went several years ago and I live in a house with harsh bare walls and a tiled floor. Even the new TV sound is muddied bouncing off everything.
> How times have changed.


I have to say I disagree as I like surround sound . I listen to music in stereo though .
My build was going to include a rear subwoofer at one time . It was kind of funny as at one time I was going to have 100 amp sub panel just to run my home theatre .
Paradigm recommends a 20 amp circuit for there 12" subwoofer , so I'd need two 20 amp circuits for the subs . 
The Anthem P5 needs two 15 amp circuits to run it properly (it has two separate 15 amp plugs, but I would run two 20 amp circuits) , 
then I was going to have a 20 amp circuit for the rest of the stereo (which is unnecessary,but I like headroom ) .
Not a really Green system .

I don't have that kinda disposable income anymore, so I don't think it's going to be a reality any time soon . 
The anthem P5 is $11,000 Canadian . Kinda sucks as it's unchanged from 7 years ago , yet they increase the price a $1,000 each year 
It's a crazy amp though , 325 watts x 5 , and weighs 130 pounds . Was going to build a very heavy duty stereo stand too support it


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## Tonto1 (Nov 10, 2016)

Carpeting is very good at absorbing the higher frequencies. Like anything, too much & the room will start sounding dead. That is where diffusion comes in. It really is best to use a combination of the 2. Typically the front wall needs significantly more absorption, side walls--a combination, and diffusion on the rear wall. You need at least 4 ft between the diffusor & the primary listening position to be effective. Ideally, one would construct the room, measure with REW (room equalization wizard--available @ Hometheatershack.com as a free download), obtain the best room response with speaker positioning,* then *treat the room accordingly based on the measured results. Often times, people treat their rooms first & then measure (often limited in the ability to reposition the speakers). Kinda putting the cart before the horse. But we do what we have to do. Most of us treat our rooms for HT & Stereo (we pull the mains out into the room (with much effort to find the best placement) for 2 channel listening!

Oh I digress! Back to woodworking. One of my friends has lots of tools. I think I will check with him to see what I can use (never borrowed anything from him--maybe, maybe not. I'm liking the idea of using a table saw & dado followed by a router. The width of these panels is fixed & if I remember correctly, the design calls for 7 panels mounted side by side. My ceiling is 8 ft & my riser is 10" high. I'm thinking 6 ft panels should do the trick.

The possibility of warping does concern me. I hadn't thought about that. The room has an oversized AC duct & its own return. Did that on purpose to try and help with a steady environment for my equipment (coldest/warmest room in the house). Do you think that will help? Any thoughts on what kind of material would hold up the best? I could use MDF, plywood (hardwood or pine) for the basic structure, not sure what my choices will be for the machined pieces. I could probably figure out a was to leave the back open & glue & screw the machined pieces to it. Then attach the back/base piece. I'll look at the plans again.

Again, thanks for all your advice!
Quenten


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## Tonto1 (Nov 10, 2016)

You may come out cheaper to run a large cable from your panel to a sub-panel in the equipment room & have the needed breakers there with short runs to the electrical outlets.


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## RainMan 2.0 (May 6, 2014)

Tonto1 said:


> You may come out cheaper to run a large cable from your panel to a sub-panel in the equipment room & have the needed breakers there with short runs to the electrical outlets.


Yes the sub panel would be the answer . As it is I've kiboshed it and am running two 20 amp circuits, one branch for the sub and one for rest of the stereo .
My Marantz amp only claims to draw a maximum of 660 watts with all 5 channels driven .
My dream amp , the Anthem P5 draws 3600 watts . There is a newly released amp from Anthem that is smaller and less expensive . I believe it's 225 x 5 .
My Marantz is 140 x 5 (from memory) , and Paradigms studio 100's really shine with a bigger amp . 
I have the last generation of Studio speakers made before they dropped the line . Went with the cc690 for the centre channel and 4 Studio 100's for the surround


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## sunnybob (Apr 3, 2015)

I had a pretty good stereo hi fi set up of that age, but never had the inclination to go surround sound. I just couldnt accept that I was listening to things in front and behind at the same time. 
'taint natural.


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## RainMan 2.0 (May 6, 2014)

sunnybob said:


> I had a pretty good stereo hi fi set up of that age, but never had the inclination to go surround sound. I just couldnt accept that I was listening to things in front and behind at the same time.
> 'taint natural.


Yes for music that only makes sense . But for movies surround sound is awesome . I don't know how many times I've had the **** scared out of when some noise unexpectedly came from the rear speakers . 
I've even had to rewind the movie when I thought someone was knocking on the back door lol


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## TWheels (May 26, 2006)

Tonto1 said:


> Hey C-Chuck, thanks for the quick reply. I posted those pictures too fast this morning & didn't really mean that design. This is the one I am thinking about.
> 
> http://arqen.com/wp-content/media/acoustic-diffuser-fractal-588x315.jpg
> 
> ...


How about taking essentially that layered build up and then use appropriately sized ovolo bits to route rounded surfaces that will create grooves separated by rounded ridges?


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## whimsofchaz (Jun 6, 2013)

sunnybob said:


> I had a pretty good stereo hi fi set up of that age, but never had the inclination to go surround sound. I just couldnt accept that I was listening to things in front and behind at the same time.
> 'taint natural.


Don't your ears hear behind you? That is why they made surround sound because you can.


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## sunnybob (Apr 3, 2015)

True, but I didnt like the effect of an instrument suddenly starting up behind me. I'm too used to the band being in front.
Same with home theatre, I like to watch, rather than be in the movie.


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## Tonto1 (Nov 10, 2016)

I'm leaning towards this Dado blade set.

http://www.rockler.com/freud-8-professional-dado-set-sd208?utm_source=bing&utm_medium=cpc&utm_campaign=(ROI)%20Shopping%20-%20Top%20Sellers&utm_content=power+tool+accessories&utm_term=saw+blades"]http://www.rockler.com/freud-8-professional-dado-set-sd208?utm_source=bing&utm_medium=cpc&utm_campaign=(ROI)%20Shopping%20-%20Top%20Sellers&utm_content=power+tool+accessories&utm_term=saw+blades

From what I hare researched, seem like they make quality blades. It will depend on the table saw if I get the 6" vs 8".


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## Tonto1 (Nov 10, 2016)

Do my posts have to be approved? Seems like I post reply's & they don't show up??? This is the same forum template as HTS, don't see that problem on that site. I posted in this thread twice yesterday but they aren't showing up. Just wondering .


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## Cherryville Chuck (Sep 28, 2010)

Freud makes very good blades Quenten. 

I had problems years ago when I first joined and I think it was the wireless internet provider I had that was the problem. I especially had problems in the late afternoon and early evening when all the school kids would get on the net and drop the bandwidth. One other problem that can be experienced is the time it takes for your post to load onto the forum. Give it a little extra time before you click on something else to see if that helps. It it persists we can ask Admin for help.


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## Tonto1 (Nov 10, 2016)

Just an update:

I've been researching table saws. It seems like a nice saw is going to be out beyond my budget. Funny thing, I was talking to one of my coworkers about this project & he tells me he has 2 extra's in his shop. He has what he thinks is one from Harbor Freight that is a 13 amp/2 HP unit & a Hitachi (not sure of the specs). He is going to bring me the model #'s so I can look them up. He says very little use on them. He found a contractor saw an a garage sale for $25 in great condition. He tells me I can have my choice of the two for the same $25! Talk about paying it forward!

I'm still pondering the wood. The plans look like plywood would work for a lot of the basic frame. Any recommendation...regular stuff from Lowes/Home Depot. Or should I look at a better grade...hardwood vs pine?

And I agree about the rounded tops. I will be going with that. Hoping I can find a 1/2" piece of molding that will work. That would make it easy.

Well it's getting late. I will talk with you guys more later. 

Again, thanks for all the helpful advice!
Quenten


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## RainMan 2.0 (May 6, 2014)

Congrats on the table saw , great news 

I'm wondering if mdf would be the best choice seeing as it's so dense? 
I'm not as big a fan of mdf as I was before I joined here , but it has its places , like speaker enclosures .
Make sure you have a good mask if you decide to use it though , as the dust from mdf is nasty


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## Cherryville Chuck (Sep 28, 2010)

The main issues with small cheap saws is the quality of the fence and the shortness of the table past the saw blade. Some saws can be upgraded with a better aftermarket fence. Some of the cheapest saws can't be modified as the edges either aren't made to attach a different rail to or aren't strong enough.

A friend had an old Rockwell Beaver 10" that he wanted to upgrade and I wanted to give the in laws my old Craftsman back up saw so they would stay of out my shop, particularly after the FIL took my brand new Freud glue line rip blade and cut a bunch of 23 gauge pin nails in half with it. The friend sold me his old saw for $100 and it had a 220 motor on it already which was good for me. I had a Mule/Accusquare fence which was about $275 to replace the old fence with although the old fence really wasn't all that bad.

If those saws prove to be a little light and maybe not good enough for you then keep an eye on want ads and Craig's list because they do come up from time to time. I added a bit of an outfeed table to mine and it cuts almost as good as my unisaw. When you know what the models are post them as some members may have experience with them.


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## Tonto1 (Nov 10, 2016)

Yeah, I figure it is not a great saw. I'm hoping it's enough for this project. I reminded David last night to bring the model numbers & he said he would (try to remember)! You are right about the small table. We actually talked about making a work table that I could put the saw into. 

Thank's for the advice on the MDF Rick. Do you think it will be less prone to warping? Agree that dust will be an issue. I have a shop vac that I can attach to the saw. Do those things really work? I will be in my carport as well so that should help as well.


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## Tonto1 (Nov 10, 2016)

Hey, one more post and I can provide links!


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## harrysin (Jan 15, 2007)

I've sat back reading this thread with a certain amount of amusement, having spent my 50 year career in the consumer electronics industry, many of those years as service manager to three specialist Hi-Fi businesses dealing with the esoteric end of the industry, it never ceased to amaze me how few customers had been to live concerts and so had no basis for comparison, rather, they had their own impression of what instruments actually sounded like. Hi-Fi, or high fidelity by definition is "the closest approach to the original sound" In a theatre, simply changing a few seats either way will affect the sound that one hears. Part of our service consisted of installing the new equipment which would include an equaliser, and equalise the room by tripod mounting a calibrated microphone approximately where the audiophile would normally sit and feed a pink noise generator into the amplifier and adjust the graphic equaliser for a flat response as shown on the print-out. In many cases things had to be done to the room, like rugs on a tiled floor and heavy drapes over the windows. I have been retired since 2000 and certain things may have changed, but not the principles!. By the way, Bose 901's were a very popular speaker in the 80's here in Australia.


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## Tonto1 (Nov 10, 2016)

David brought in the owners manual for the Hitachi. Model C10RA3. 15 amp/3.5 HP (Maximum developed). Anybody have any experience with this saw?

http://www.hitachi-koki.com/manual_view_export/pdf/C99150063_C10RA3_605.pdf


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## Cherryville Chuck (Sep 28, 2010)

I'm not personally familiar with it Quenten but I do like Hitachi tools and have had good luck with the 2 big plungers, an M12VC, and an air operated 23 gauge pin nailer. The main thing is the fence and the picture of makes it look like it is one of those saws that cannot be retrofitted with an after market fence. Line it up with a miter slot, lock it, and see if it lines up with the edge of the slot. If it doesn`t see how hard it is to get it adjusted so that it does. Once adjusted unlock it, move it away, move it back again and see when relocked if it still lines up with the miter slot. If it doesn`t you will be continuously fine tuning the fence to get the saw to cut right. Once locked also check to see how easy it is to deflect the fence. I had a small saw similar to that one and I had to glue some sand paper on the clamp at the back of the table to keep the tail end from sliding around.

On the other hand, if you are buying this mainly just for making the diffusers then it's probably good enough especially if you get it for $25. You could be using this one while looking for a better saw and probably still get your $25 back if you went to sell it. The Hitachi tools I have have been very reliable. If you can build an outfeed table behind it you will be grateful you did. The distance behind the blade is very short.


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## Tonto1 (Nov 10, 2016)

Thanks Charles, I'm thinking the same thing. I see that it says the maximum Dado width is 1/2" (12.7 mm). I think the diffusor has 10mm wells so it should be ok. I'm also thinking I can use the straight blade for cutting the outside grooves since they are only 2 sided. That will save 2 dado cuts on each 2x4.


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## Tonto1 (Nov 10, 2016)

Just for giggles, in case anybody is interested. Here is a picture of the riser I'm building. 2X10's notched top and bottom with a ripped 2x6 on the front & back + two more under the plywood where the theater seats will go (added support...probably overkill, but hey, better safe than sorry). The diffusor panel will be going on that back wall. Please excuse all the junk (wife needed to store some stuff temporarily). I still have to pull electricity for the seating...shouldn't be difficult.


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## RainMan 2.0 (May 6, 2014)

Ok sorry , I didn't see the picture the first time I checked . Looks like you have it figured out.

I recently sat in a kind of chesterfield home theatre setup that had power reclining , and omg was it sweet . 
Not sure if it will get threw a 30" door though 

Just wondering what your doing for the rear speakers ?


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## Tonto1 (Nov 10, 2016)

That could be a problem. I had them install a 36" door for mine during the renovation just for that reason. Thank goodness they can be disassembled!

The only tool I had to build that riser was my Milwaukee Circular Saw & a Passload nail gun. I know it's hard to see, but that 3/4" plywood deck is really a tight fit that required a bit of work to get perfect. The room is not square & I'm way too meticulous! I had to allow for the back wall irregularity and the cuts around the equipment room door. It extends into that room such that when to door is closed, there will be a tight fit. My carpet guy said he needed 3" to glue the carpet down. That's why I ripped the 2x6.


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## RainMan 2.0 (May 6, 2014)

Well I was wondering if the one I like can be disassembled , and I was there today in there paint section , and I forgot to check darn it . 

Now I understand why people mount there flat screens so high , as when you recline those home theatre seats to get that sweet spot comfort zone wise , your head naturally goes back to a point where your looking at an angle towards the ceiling


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## Tonto1 (Nov 10, 2016)

That's why you demo your seating before buying! The head rest should be positioned so you are comfortably looking at the screen. If you wind up not being so lucky, just add a throw pillow onto each chair!


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## Tonto1 (Nov 10, 2016)

I bought the Hitachi table saw just now. It looks to be in great shape. I'll go ahead and order my dado blade tonight. Still wondering what type of plywood is recommended vs MDF. Any thoughts! I looked online at Lowes/Home Depot, 4x8 sheets of MDF & Birch Plywood are both ~$30-$35. I would expect the plywood to be easier to cut & weigh less--don't know for sure. Regular plywood can be had for <$10!


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## RainMan 2.0 (May 6, 2014)

Tonto1 said:


> I bought the Hitachi table saw just now. It looks to be in great shape. I'll go ahead and order my dado blade tonight. Still wondering what type of plywood is recommended vs MDF. Any thoughts! I looked online at Lowes/Home Depot, 4x8 sheets of MDF & Birch Plywood are both ~$30-$35. I would expect the plywood to be easier to cut & weigh less--don't know for sure. Regular plywood can be had for <$10!


I'm still thinking mdf because it's so heavy and won't resonate , but it will be interesting to hear what the elders have to say .

Personally , my thinking is making diffusers with some sort of fabric on it to absorb instead of reflecting sound waves , but I'm no expert .
Are you going to use a RTA to check for peaks and nulls?


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## Cherryville Chuck (Sep 28, 2010)

Tonto1 said:


> I bought the Hitachi table saw just now. It looks to be in great shape. I'll go ahead and order my dado blade tonight. Still wondering what type of plywood is recommended vs MDF. Any thoughts! I looked online at Lowes/Home Depot, 4x8 sheets of MDF & Birch Plywood are both ~$30-$35. I would expect the plywood to be easier to cut & weigh less--don't know for sure. Regular plywood can be had for <$10!


If you can get birch ply for the same price as mdf then I would. I use a lot of mdf but because of price difference rather than other reasons. The stuff is nasty to work with.


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## Tonto1 (Nov 10, 2016)

Rick wrote:



> Personally , my thinking is making diffusers with some sort of fabric on it to absorb instead of reflecting sound waves , but I'm no expert. Are you going to use a RTA to check for peaks and nulls?


There is a place for absorption, not here. There is a fine balance In placement.
I will use my XTZ Professional Room Analyzer & REW. As well as room correction software once I get the room as good as I can.


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## Tonto1 (Nov 10, 2016)

Charles wrote:



> If you can get birch ply for the same price as mdf then I would


Birch it is then.


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## RainMan 2.0 (May 6, 2014)

Tonto1 said:


> Charles wrote:
> 
> 
> 
> Birch it is then.


Yes the dust from mdf is terrible and known to be bad for lungs . I take my mask off 10 minutes after making a cut and I start coughing . That's gotta say something .
Baltic birch is now my all time favorite material , but it's $105 after tax for a 5'/'5 sheet of it in western Canada


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## Tonto1 (Nov 10, 2016)

Wow, that's pricey! I think I'll use the Sande vs the Birch as it's a little cheaper. Unless you guys are aware of any difference.

Sande Plywood (Common: 1/2 in. x 4 ft. x 8 ft.; Actual: 0.472 in. x 48 in. x 96 in.)-454532 - The Home Depot

Columbia Forest Products 1/2 in. x 4 ft. x 8 ft. PureBond Birch Plywood-833185 - The Home Depot


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## RainMan 2.0 (May 6, 2014)

harrysin said:


> I've sat back reading this thread with a certain amount of amusement, having spent my 50 year career in the consumer electronics industry, many of those years as service manager to three specialist Hi-Fi businesses dealing with the esoteric end of the industry, it never ceased to amaze me how few customers had been to live concerts and so had no basis for comparison, rather, they had their own impression of what instruments actually sounded like. Hi-Fi, or high fidelity by definition is "the closest approach to the original sound" In a theatre, simply changing a few seats either way will affect the sound that one hears. Part of our service consisted of installing the new equipment which would include an equaliser, and equalise the room by tripod mounting a calibrated microphone approximately where the audiophile would normally sit and feed a pink noise generator into the amplifier and adjust the graphic equaliser for a flat response as shown on the print-out. In many cases things had to be done to the room, like rugs on a tiled floor and heavy drapes over the windows. I have been retired since 2000 and certain things may have changed, but not the principles!. By the way, Bose 901's were a very popular speaker in the 80's here in Australia.


Harry ,now most high end processors have built in circuitry for room correction . My old Yamaha amp/ processor came with a mic and I put it on a tripod where I sit . The system first sent pink noise threw each speaker individually , then white noise , then pinged . I'm assuming the ping was for setting individual time delay in each speaker . 
And I'm guessing the white noise was setting up its parametric equalizer. 

Of course your right , as furniture carpet and curtains etc can change a room acoustically.


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## Tonto1 (Nov 10, 2016)

My computer died (at work now) so I can't post any pictures, but I bought some feather boards for the table saw. It has a unique miter gauge trough so I had to custom make the rod. I cut down a piece of oak firewood & made the piece to fit the trough. It was an exact fit! I didn't account for the wood being a bit damp & of course it dried out and shrank a tiny bit, still a pretty good fit though. 

I'm getting ready to build the extension table for behind my table saw. Would love to see pictures of everybody's table. I figure you guys have some great ideas. I'm thinking of a double purpose table. It would attach on the back of the table saw & have a cut out (half way down one side) for my miter saw to double as wings for it. I think I can cut out a square and build a box below the cut out to so I can slide it in when I need to use it. I'd replace the cutout when using the table saw. Anybody done that? Are there more practical things to use the table for?

I can easily wire it where all I have to do is plug an extension cord to it & have power at each saw as well.


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## RainMan 2.0 (May 6, 2014)

I haven't seen that done yet , but sounds like a valid idea if your short on real estate .
I made my work station just a tad under my table saw height and use it for the rear extension . 
My thought though was to install a router on each side of it . Although it may be uncomfortably low for some people , so I also wanted to design it in such a way that I could change its height . 
This is after I insulate my garage


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## Tonto1 (Nov 10, 2016)

Thanks Rick, space is at a premium at my house. Working in the carport actually. I can see where this hobby can be a lot of fun. Especially when you have nice tools & a bit of know how! Really looking forward to getting everything set up.


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## Cherryville Chuck (Sep 28, 2010)

I have 2 saws and one is a big cabinet saw so it wouldn't apply to you as the current one is 4' x 3' deep and I'm rebuilding it for 4' deep. My backup is a contractor saw and I added about 9" out the back on it. More would have been better. Make it as long as is practical.

Because the out feed on my big saw is as large as it is it winds up being a work table a lot of the time.


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## RainMan 2.0 (May 6, 2014)

Tonto1 said:


> Thanks Rick, space is at a premium at my house. Working in the carport actually. I can see where this hobby can be a lot of fun. Especially when you have nice tools & a bit of know how! Really looking forward to getting everything set up.


Yes this is very addictive . Stay away from MT Stringers posts , as he always seems too cost me money .
Mike practically bankrupted me , and I'm not done yet


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## Jidis (Aug 22, 2015)

Tonto1 said:


> I was thinking I could use plywood & lumber for the basic design. That would be easy.


On a slight side note- Years ago, I built a quadratic residue diffusor for my studio's control room. Can't remember the exact range it covers, but it ended up involving some serious compromise after doing some calculations. Just to get down into what was probably lower midrange, the well depths ended up being around five inches or more. Then, when working with sheet material which is only a half or three quarter inch thick, one single period of the diffusor eats up a whole sheet and is only a few inches wide! It gave me a whole new perspective when I look at shots of other people's studios with fancy full wall diffusors using hardwoods and all. 

The sizes and material I was initially considering would have been like hanging a small automobile on the wall. I ended up going with a styrofoam sheet insulation and painting the final unit with a mix of PVA glue and primer to protect it. The outer frame is 3/4" pine. Even then, it's only about four or five feet square total. I've got a few sheets stored for another one, but chickened out after some discussion online about the well dividers. Mine was done with none, but evidently, it doesn't quite reach its target performance with them open like that, despite all the pictures I see with no dividers. I thought about trying to add them this time, but even the thinnest stuff I considered would be worse (weight-wise) than the square footage of the well parts, as each divider needs to be_ maximum _well depth, whereas the wells range from minimum to maximum. On top of that, anything thin would be too fragile with the edges exposed unless I used something like tempered masonite, then I'd be right back to "car on the wall". 

Sorry for all the off-topic text, and good luck on it. It's a rewarding job!


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## harrysin (Jan 15, 2007)

RainMan 2.0 said:


> Harry ,now most high end processors have built in circuitry for room correction . My old Yamaha amp/ processor came with a mic and I put it on a tripod where I sit . The system first sent pink noise threw each speaker individually , then white noise , then pinged . I'm assuming the ping was for setting individual time delay in each speaker .
> And I'm guessing the white noise was setting up its parametric equalizer.
> 
> Of course your right , as furniture carpet and curtains etc can change a room acoustically.


It doesn't of course surprise me that things have changed. Yamaha, now that is a name that I was very familiar with, being an accredited service agent for a few years. A story about Yamaha is worth repeating, one of their top of the range amplifiers came in after being used at a wild party with all four VFETS "blown", when replacements arrived the cost was a little over $300.00 EACH! The Australian distributor dug their heels in so I telexed Yamaha in Japan and received a quick reply saying that they thought the price was a "little high" and they would contact Rose Music, the Aussie importers. A day or two later another telex arrived from Japan saying that they had a rethink and the price was correct!!!!!!!!!!!
I reckon that Rose Music were more than a little upset at Japan's first reply.


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## RainMan 2.0 (May 6, 2014)

Wow Harry , to think that each of the finals was 300 bucks a pop is ludicrous !


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## harrysin (Jan 15, 2007)

That is exactly what I told them. Amazingly the client had an "all events insurance policy", something that I had never come across before or since and they paid without question, now that for an insurance is AMAZING!


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## Tonto1 (Nov 10, 2016)

Well I'm getting much closer to starting! I have the table saw, bought n Bosch 18 volt cordless drill (nice set of drill bits as well as the a Bosch 20 piece bit assortment). Got a HF 15 amp sliding compound miter saw (couldn't resist @ $129--well see how it holds up). I had to take the first one back. I was able to get all the angles corrected except the 90 degree cut. The second one is spot on for now, we will see. Got a digital caliper, which makes measuring small cuts super easy! 

The first thing to build will be my table for behind the saw. I also have 2 35 gallon plastic barrels. Would like to make a dust collector with one of these. I get them free at work if anybody close to Tallahassee want one. I'm going to custom build another piece that will fit my table saw fence to mount another feather board to hold the wood down. 

Need to build a push block also. Feel free to post pics of yours. Any particulars to what makes a better push block that I need to know? I really don't like putting my fingers that close to the blade, the feather boards will help. The table top is so small as it it. I'll probable build a better table around it before it's all over. 

One of my neighbors brought over his wife's Christmas present to hide & come to find out he used to be into woodworking! He is going to lend me his Dado blade so I don't have to buy that if it is in good shape. So all in all I'm slowly getting there. Hopefully after Christmas since it seems all my $'s are going towards that right now. I'm getting excited! 

Hope all you guys have a Merry Christmas!


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## Cherryville Chuck (Sep 28, 2010)

This link may help with the barrel: J. Phil Thien's Cyclone Separator Lid w/ the Thien Cyclone Separator Baffle There's more on our forum if you do a search for Thien.

The push block depends on how wide and how high you have the blade. Here are some of the possibilities. I like to have one made out of 1/4" ply like the 4th from left on the top row and 3rd from left on 2nd row. https://www.google.ca/search?q=tabl...LVsPTQAhXrgVQKHcGvAVQQsAQIIg&biw=1920&bih=969 They work well when ripping thin strips.

Another ready made one is the Grrriper: MICROJIG - Work Smarter but as you can see they are a little pricey. Some of the members have them and love them.


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