I am feeling that my system is at the point where I can appreciate some fine tuning.  The last big step to getting here was the LPSU in my Mac Mini.

So I was reading a post on the forum and isolation was mentioned along with this link: http://www.barrydiamentaudio.com/vibration.htm   Thanks to whoever posted this BTW.

I've been kind of an isolation skeptic, mostly driven by the marketing hype and high cost of most isolation devices.

But this article made sense to me and the cost could not be beat, so I figured what the heck.

The gist of the article is simple, you need to control vibration in the vertical, horizontal and rotational planes simultaneously.  Most other (expensive) solutions don't address all three.

Sounds complicated, but it is achieved easily with about $10 in parts.  A bicycle tube, a piece of plywood, 3 ball bearings and 3 concave, round drawer pulls and some bluetak.  I got everything except the plywood at Ace Hardware.

Basically the plywood goes on top of the inner tube, and the concave drawer pulls are each imbedded in a small chunk of wood (with the bluetak to deaden them) with the ball bearing placed on top.  The drawer pulls are place in an equilateral triangle. You then rest your gear so it balances on top of the three ball bearings.  It may sound a bit unstable, but its not.  Surprisingly, its pretty stable.

I did this with my MK III and also my Mac Mini.  It will definitely change the sound.  I think you have to follow his recipe exactly or it may change the sound to something you don't like.

I am not where I want to be yet but it is quite promising.  When I did the amp alone, it sounded great.  Tighter bass, more extended highs.  GREAT detail.  But when I did the mini, now the highs are too hot and fatiguing.  I think it has to do with how I did the drawer pulls. I have a plan to fix them.

Once I dial this in, I am going to build a nice version of it using better wood.  I am also going to "float" my speakers in the same way (minus the innertube).



Anyway, some will dismiss this as bunk.  I am glad I didn't.  I think it is a cost effective way to isolate your gear and improve your sound.

I read that article some months ago. makes good sense. but, I have not acted on it. Let us know your findings once you've had some time to tweak.

Edit, oops, Archie got there first. Sorry for redundancy.

Looks cool. I looked at this some years ago, but it seemed a little complicated, messy, and time consuming, though I have little doubt you could do it tastefully. And what is the resonance of the plywood, and how much gets through the egg holders and marbles or bearings? I have little doubt it has some sound....but probably not much....just depends how much and what it does sound-wise.

So I just paid 75 or so (maybe 90 now?) for some isocups. Speaking of which, Lon and I and others have found you can tune Herbie's isocups, with different "marbles." Could be a good tool one day for fine tuning. Since most designers have not used this level of isolation in their voicing, it can present some challenges and I think different materials, methods and shapes can help with this. I find that I really like several different isolation tools and combinations for different gear. It may not be total, but it is another tuning tool for getting the sound just right for each part or shelf. And they do all sound different.

Archie made some platforms that were really simple and supposed isolate from all directions...two pieces of MDF with springs cut and fitted in correctly placed guide holes on each piece of mdf. Seems the springs might drain vibration well. I have not had a chance to try this, but am interested as a pretty simple solution.

I have some green marble 12 X 12 tiles you can try out. I bought them probably 15 years ago and used them on top of my Decware subwoofer to add some density to the top and help hold it to the floor (LOL).

I am starting to understand your feeling of wanting to stay put on your system Lon. Seems now everything now has an impact and you then have to figure out if it's good...should you go back to where you had it before, etc.  Can be maddening.

Raven if you can pick those tiles up with two fingers and ding them and they thud instead of ring, I will buy them from you.  Good ones that don't ring seem hard to find.

I think there are infinite ways to deal with resonance and vibration, both mechanically coupled and air born.  I am convinced there are very effective ways to reduce both - inexpensively.  Palo has likely stumbled upon one of the many possibilities.
If cosmetics are not too terribly important to you... try this:
I cover the top of my equipment rack shelves with 1/2" thick cork from Bangor Cork - inexpensive and damps the shelves from resonance and vibration and decouples the shelf from your components.  Then for any component that do not have ventilation vents in the bottom, they sit on 2-3" thick convulated(egg crate) foam sheets which are sitting on the cork (I got the foam idea from when I visited one of the most well known amp designers to ever live, and saw all his equipment sitting on it).  This adds another layer of isolation of the shelf from the component and also damps the "entire" bottom of the component chassis from mechanical and air born resonance and vibration.  For components, mostly source, that don't have vents on top.. anything that adds mass will change the resonate frequency of the chassis - this is trial and error to see what effect it has and whether or not you like the effect.
Mostly, here again I have gravitated to the convoluted foam, with a little something on top of the foam to press it down to have good contact with the top of the component chassis.  Now we have the component nearly encased in 2-3" of foam.  Don't believe me - try it - it works - cheaper than dirt.  
I also have a whole box of 40 durometer sorbothane 12" square tiles I bought from some guy years ago.  Great stuff... you'd be surprised what very high-tech devices and components are protected from resonance with sorbothane.  Problem with sorbothane, is that it will discolor the chassis of pretty much anything if left in contact with it for long.  So... here cork enters the equation again.  Cut a piece of cork the size needed, place it on the component, then lay the sorbothane tile on the cork.  
For stuff that has vents top and/or bottom... we can still cover the shelf with cork, and then maybe sorbothane or foam, and then a piece of wood or something on the foam, and then sit the component on that.  I also have a whole box of the old Sims Navcom pucks.  Navcom doesn't muck up finish as bad or as fast as sorbothane, but with enough time, they will cause a bit of discoloration too.  But these can be used to provide decoupling and space between the component and the foam sandwich when venting is required.
There is a guy on audiogon that makes and sells cork resin/birch plywood pucks in a couple of styles and shelves and I think maybe even complete racks made this way.  I have two of the styles of his pucks.. use them to contact the component chassis and then sit them on the cork/sorbothane/foam sandwhiches, for stuff that needs venting.  I am very pleased with the results of this stuff - and the price!  My favorite method is the "encase in foam" approach where I can.  If the mechanical and air born resonance and vibration can't "get to" the component, it can't cause a problem.  I have even envisioned building an enclosed audio rack with this same methodology to completely prevent resonance and air born vibration from getting to the equipment.  It would have to have some kind of forced(fan) ventilation, at least a little bit.  And then I wouldn't be able to see the lovely glowing bottles either....  :(

Palo... please keep us posted on your experience with your isolation platform.

I started my search looking at the multiple options mentioned here on the forum and then pursuing my typical strategy of trying to get the same value for less than half the cost.  May sound like a pain to some but part of the fun for me.

Anyway I read opinions about sorbothane and cork, tried foam and blue tack and as you say stumbled upon this link and tried it initially with just the ball bearings on wood and the tube and got a good lift in definition and bass detail.

So the next day I stopped and got the drawer pulls and that cinched the deal.  Great detail, nice shimmer on the cymbals and best of all was the bass definition.  I listened to some music that was on my old old demo playlist and couldn't believe the bass I was getting.

The only one of the commonly cited benefits I wasn't getting was increase in soundstage size and depth.  I have a fairly treated room and had decent soundstage going already.

I think there are many ways to skin a cat.  I just liked the mechanics of this solution.  Kind of like when I first read about decware.  The whole concept sounded right.  

Anyway I tried it and it worked despite the fact that I am using a POC Ikea table as my "rack."  It motivated me to try a second platform and today I want to try floating some speakers.  

As soon as I can get to the hardwood store I am going to buy some birch ply for the platforms.  If I am still in love with this after some time has passed and some tweaking I will build a proper box for each.

I have been working on a post that talks about a suggested sequence of steps in building your system.  My journey has been somewhat random and I thought if I ordered it more efficiently it might save the next guy some time and money.  Anyway now I have to think about where isolation fits in the sequence.

Thanks for keeping on it Archie. I will try your method one day. Just hard for me to get to the store....busyness, disabilities and whatnot.

Palomino. Is it that you are just beginning to notably hear vibration control due to "skepticism" causing you not to seriously try it. Or is it that it just couldn't be heard notably before. If it is the later, after all the work you have done, it could be worth a close look for one or more weak links in your system/room...If it was the LPSU for the Mini that really brought up your resolution enough to hear this subtler stuff...maybe it is all good now, but I don't have an LPSU and have always been able to clearly hear vibration control, the sound of different materials, shapes, placement etc. Jus makes me wonder if you have a secret resolution killer.

BTW, in the past there have been consistent comments with isocup users under Toriis, that where you put the balls under the amp makes a difference. Since your system has similarities to how isocups meet the amp, an equilateral triangle may not give you your best sound. Most found that the back feet were best near the back, outside corner of the outside transformers...and the front two (I got better sound with four and some like 5 or 6), usually between the front power tubes and inputs...closer to the power tubes. Then playing with pushing the front ones back can add warmth and texture. I like mine lately just in front of the rectifiers.

Will, its a combination of things.  First, I was skeptical, especially given the price of most commercially available isolation solutions.  How much lift will you get for that much money?  Second, I didn't think I would be able to hear the benefits given where I was in the evolution of my system.  I could easily have been wrong on this one.  

I actually thought the next step for me was interconnects.  I got a little gun shy when I started looking at the prices of those suggested could get me the next step (Grovers are an exception).  So I started looking around more for DIY isolation solutions.  I had tried a couple already without getting much of a lift, but I hadn't really spent any money so I figured I was getting about what I'd put into it.

Then this solution came along, was cheap, and I read lots of good reviews on it.  So far its been fun and I am definitely getting some benefits.

I floated my speakers this morning and think I got more lift.  Listening to it now so I am still trying to figure out what all I am getting here.  Soundstage is good.  Bigger?  Not sure.  Bass is tighter and more defined, but maybe a little shy.  I'll keep listening.

I also changed to a marble tile under my amp.  I was getting concerned that the ball bearings would dig into the wood base.  I don't think this problem exists with the iso cups.  Anyway, the inventor suggested the tile so I'm giving it a try.

Finally, I cut a new piece of plywood which extends the full length of my "rack."  Dumb move because the amp is heavier and tilting it.  I'll have to cut this in half and float each half independently.  It's pretty cold outside so this is a nice way to pass a cold Saturday.

I agree with Archie on the bass and decoupling.

Quote:


I thought this was a very good explanation as to why Speaker Isolation my result in either a perceived Increase in Bass in some cases or perceived Decrease in Bass in other cases:

Quote:


See comments section at the bottom of the review at this link. I thought the comments regarding listening rooms with concrete floors were interesting also:

http://www.htguys.com/news/2010/12/5/auralex-subdude-video-review.html

In my case on a typical wood suspension floor, placing Sub Dude II isolation platforms under my two down firing Mid Bass Modules reduced floor & wall vibration by about 50%. Placing Sub Dude HT isolation platforms under my two forward firing 15" Subs reduced floor & wall vibration another 40%. My floor & couch no longer vibrate at moderate and higher volumes but the bass is cleaner and more articulate which makes vocals and other details within the music much easier to hear.

I now have Sub Dude HT Isolation platforms under my Klipsch RF-7 mains. I think there is an improvement when playing at moderate and higher volumes. No where near as dramatic an improvement as with the Mid Bass Modules & Subs however. Point being, depending on your room & speakers you might not notice an improvement by isolating your main speakers.

I would think bottom vented speakers like Zu might benefit from Isolation. Stand mounted Monitors may also benefit by eliminating metal speaker stand ringing.

Very nice Pal. I have my System configured on the floor on wood platforms. I do not like racks. I use some Herbie Halo stuff and a Townsend CD Seismic Sink for DAC(s).

I know I need to get that power supply for my Chord QuteHD...been dragging my feet. You offered to buy it...so it must make an improvement.

I love the NOS 6922 Sovtek's you can't get anymore...in my SE84CS input (I own a few of them knowing they would dry up like the NOS SV83's...so I own a few of these too...if you know what I mean)...of course, with my NOS SV83 Svetlana's. I have yet to try one of my awesome Telefunken's in my CS yet, but I will. The clarity and sweet nuance I'm getting out of this tube in the input of my CSP3 is piss your pants....no hyperbole.

There is another company (Steve Blinn Designs) that is getting into the IsoPed footers.  I think they are taking a direct aim at Stillpoints and possibly even VooDoo.



He also designs some pretty nice audio racks as well.  And his prices for the footers and racks are pretty good.

I believe all Blinn's designs are custom so you could potentially order a rack any way you want it.  I enjoy low and wide component shelfs as well.  Because I only have one place to listen and watch movies so I have a large 65" HDTV/Monitor to deal with and I like it to hang at eye level which only allows me about couple feet so I go horizontal intead of verticle with my components.

This is an older pic (of my Rega Kit which now resides in my bedroom), but my stand is the same ... it's not an audiophile rack by any means, I picked it up from Ikea actually, but I like the way the components are laid out this way.




Behind the doors I keep my Monster Power Conditioner, Spin Clean record cleaning machine and a few other odds and ends.

Great! So glad you tackled this and this methodology is a good start and I'm glad you have found sonic benefit.

On a contradictory note: I was surprised at how much my PPP and P5 responded to the Iso-Cups and Iso-Pods!

It's really hard to say which is "more" for me. Like the amp the P5 responds with subtle differences to where the feet are placed, and both are on PowerBases which give them the bulk of their isolation improvement. I would guess that the improvement was very similar in scope between the amp and P5 and the speaker improvement was different in nature (less about tonal balance than tonal balance and resolution) and perhaps not quite as extensive, but our speakers are quite different. Also, the P5 seems to let me "hear more" than the PPP did, but I did get improvement from isolation with the PPP, considerable, and could hear differences with different configurations and placement. Adding a PowerBase was the biggest change.

Anyway, I found that I got an improvement from the methods you're using when I went to maple platforms, Iso-Cups and Iso-Pods and then PowerBases as well, and "heard" even more when I upgraded cabling. But at a great expense. It's hard for me to put percentages on things, and was it worth the expense? To me, with less financial responsibility at the time troubling me? Yes. I seized the moment, because I couldn't do it now. If/when your moment comes, there's improvements to be had.

Same here, 1 down, 3.5 college tuitions to go ... BTW, in a near field listening configuration, treating the room with rigid polyfoam pannels made a huge difference. These are strategically distributed, set as corner traps, first impact areas, front and back walls, etc. These were all DIY, simple and cheap. I need to cover some of them with non reflective cloth to improve the decor, but that's it ...

I wonder how much improvements some diffuser pannels alternating with my absorbing polyfoam pannels would yield, and how to order that from a non-informed local carpenter ...

The pair of DSR's that I got from Will on this forum, almost three years ago, have beaten anything I've tried so far, including some nice BAT IC's I kept from my early VTL times in the 90's. I guess cable technology has advanced at a fast pace also, not only its prices  :)

How many did you get?

Quote:


Four pair of 2' X 4' panels. I *think* they might be matched up in male/female (positive/negative) pairs so they can stack and ship together. They weren't very clear about that part and there have been a few iterations of these as they worked with their manufacturer.

I figure four across the front wall, and two for each side.


Quote:


I've said it before - I don't trust any reviewers that don't have at least some basic room treatment. And I don't count silly little pillows or magic electronic devices as room treatment.

I almost got into a row with someone on another forum. Kept bashing the DirectStream DAC and bragged about all this gear he has and provided a very impressive list of gear. Half his investment seemed to be on these little electronic devices that somehow enhance the sound. So I suggested all his gear is great and all, but what about room treatments, there is no magic ionic, electromagnetic stones that I'm aware of that can change the laws of physics and absorb and/or diffuse sound reflections. His response was something about how his super expensive speakers don't have those problems.

Really? Outside the laws of physics are they? I'm guessing that's a *no* on room treatment. Go ahead, spend more money on stones and wands and pillows from china then.

I'd go first reflection points with absorbers on stands that you could move when not in use.  

I went the bass trap route because I have a relatively small room and some bass boom issues.  You seem to have a pretty big room.

Pal, I know I said that I wasn't dedicated enough to worry about treatment but you got me interested.  Can you and LR give me a quick primer on how to find the reflection points to set up said absorbers and an easy/cheap construction and size?  I'm pretty sure I can build it.

As you said, I'd have to be able to pull them out and move them around since I bet they end up in the middle of the room.

I tried Steve's "clap test" (not that kind of clap!) and my room is likely on the lively side but fairly uniform.  I don't seem to hear bass nodes.

And down the rabbit hole we go!  

Pal, I looked at the acoustic panel build sight and followed a link or two and I think my initial impression was correct.  My room is too complicated to do much with.  Maybe I'm giving up too easily but I hardly know where I'd start.  No one even talks about vaulted ceilings.  Maybe I'll wait until my daughter moves out and I can take over her room.  ;)

That sounds like a great setup Dave!

Archie - vaulted ceilings are actually a big plus IMHO. Less parallel walls and more room (airspace) for the lower notes to stretch out.

Irregular rooms can be a benefit, you just need to work with them. I've got this stupid L shaped room which messes with my imaging, but it's got great bass and fewer nodes.

By the way, all rooms have nodes. 50Hz note has a wavelength of about 22'. So unless your room is a stadium or an open field, it probably has nodes.     The nodes in my place are fun since it's an L shaped room with openings to other rooms - so it's very difficult to predict where the nodes are going to be. I played a game where I put tape Xs on the floor, and asked friends to move from X to X while I played bass heavy music or movies. You could be in one spot and they thought I shut off the woofer it was so dead. But then you take one big step towards the back door and you feel like your chest is crushing in. I get such a kick out of stuff like that.

Guys, thanks for the help and suggestions.  Pal, feel free to share those pics with LR.  Maybe he'd like the exercise of thinking through some solutions?

My room is nominally 17'x31' with the speakers on the middle of the long wall which for about half the dept is actually more like 65 feet wide.  The ceilings slope up to 30 feet and have two 20+ foot high sections.  Very open and lofted space.  I can pull my speakers out into the room on a temporary basis only since that puts them in the walkway.  I did put gliders under the isolation platforms to help with that.  Winter is a bit tougher since I have barrels of wood  flanking my wood stove that partly block the speakers!

I actually think my sound is pretty good.  But my imaging is trapped between the speakers and only a few feet deep.  The HR-1s help but only so much.

To All:  I not only believe in acoustic treatments, but the little I've done with corner bass traps (front wall) and absorb panels at 1st relections has made a significant improvement. I am also purchasing the diffusion panels from PI audio Raven mentions earlier in the forum. I am currently getting a sound stage that is sometimes more than 90deg to my right and left and 3' to 4' wider than my speakers. Also, height of instrument placement can sometimes be 6' to 8' tall. My room  11'w x 16'l x 8'h.

Can anyone tell me if it would be a good idea to alternate diffuser panels with absorption panels along all sides of the room? Presumably, the number of absorption panels would be higher than the number of diffusers given the corner traps and the need to absorb first impact areas. This would only leave diffuser areas in-between those and maybe in the back and front walls, alternating with the absorption panels, I guess?

I currently have all my room setup with absorption panels only, and I don't have any booming or sibilance or ear-piercing effects, and the sound is neat, clear and balanced, but I wonder if my room has lost some of the liveliness that bare wall areas may bring. This is where the diffusers, I think, in my particular case, would come in and create some synergies with the absorption areas.

Instead of bare areas (tradeoff with booming and sibilance), I plan to try diffusers to enliven the room even more and see if I like the end result.

Just thinking ...

Any thoughts/experiences?  Thanks!

I am currently using diffusion at the first reflection and absorption at the second reflection points on the side.  It has been a while since I tested this, but I will switch mine around this weekend and report back.

My absorption panels in the rear of the room have scatter plates (GIK) which offer some diffusion and I will sometimes place some cheap styrofoam diffusors in the windows to reduce slap back off the glass.

I think a mixture of both absorption and diffusion is probably best.  I do recall that diffusion needs some room to breath though.  Sitting too close to a diffusor may not be ideal.    

Sounds doable, yep. I was not aware, but it makes all the sense in the world that diffusers require breathing space to send out the convoluted waves spectrum and realize their job. So, the distance between the diffuser and its adjacent absorption panels ought to be zero-ed in, probably by trial-and-error.

Somehow, having the diffuser at the first impact does not sound intuitive to me ... But, is worth trying both ways. Also, the mixed pattern of both diffusion and absorption panels in the back and front walls needs to be determined.

Now I need to find some easy DIY materials/gadgets to come up with my first rudimentary diffusers, until you guys show me the way with the ones you've ordered.

Thanks for the pointers.

Thanks, Acetone. I'll check that out.

I agree, Dave. I think we ought to try all possibilities before making a final judgement.

I keep surprising myself as how often what is intuitive is not necessarily what sounds the best, simply because we never envision all the relevant variables. It may well be that soundstage improves with diffusers on first impact. In fact, one of my doubts is whether my room has deadened too much, which may translate into smaller, less vivid soundstage.

I'll re-visit the placement of my absorption panels one more time myself (although currently the sound is great), to see if I may be overdoing the absorption approach.

Thanks for the heads up.

GIK says diffusers at first reflection points because they are proper broadband diffusers. The theory is that you want to break up and time delay the reflected sound *before* it reaches your ears. When you're using absorbers at the first reflection point, your just deadening that reflection point, mostly the high frequency where spacial queues are.

P.I Audio says absorbers at first reflection points and diffusers on either side. I plan on trying both ways to see what works for me.

Personally, I think you should just use what sounds (or measures) best to you in your room. If I had true broadband diffusers, I'd be going diffusion first probably, but I'd let my ears guide me. The truth is most of us don't have proper broadband absorbers or diffusers.

The Mad Scientist at work!

What little I know of room acoustics and treatment, in a small room "reflection" is probably what is limiting the bass. So "absorption" may be the best . . . "diffusion" . . . someone with more experience will be able to help I know. I have never been, and probably never will be, able to fully address room treatment in my listening rooms because of either renting or my cohabitant's wishes.

Also - I know you don't have a lot of room to move around, but if you do the walk around finding the boomy and suck points you'll realize that if you move your speakers and listening chair around, you have a good chance of finding a more neutral zone to sit in and make your sweet spot.

Thanks for all the ideas.  I'll do some investigating and reading tonight.  Mark

I agree with the absorbtion on the wall. The door makes it tricky but you can attach something to it. Corner traps and having the speakers aimed at them is an idea. Also those panels I`ve seen where you have 2 or 3 hanging up on the wall evenly spaced must work. I have a hanging carpet 9x6 ft covering that wall with corner bass traps that are only 3 ft high. I think I`ve sorted most of the relection and it all sounds good. Ive read your posts about pronounced top treble Mark and a `bright` room is also to be considered as well as the bass boom.
You could kill two birds with one stone.

I wonder when Steve will be bring the `bounce mats` on stream.

For what is worth, my room is also small and almost square (not a good thing) and what made a big difference was installing absorption panels around the sides and on the corners.

I feel I may use some difussion now, to maybe enliven the sound a little bit, but in general, the main issue is reflection and it not only relegates to low frequency but also high frequencies, which tend to become buzzy as the bass becomes boomy.

My DIY cheap panels are placed on wooden stands and I can move them around to optimize placement. I could never be back to what I had before those absorption panels.

Thanks

I`ve been looking for a  `spring` idea for sometime since Archie posted about his islolation base and the spring vibration damping qualities. I`d just found a compression spring site and was going to buy 50 springs for around £30.00 and do something with superglue and  bases.
I found these today and bought his last two sets ( 8 pieces ). £32.00 inc post. Looking forward to them and if they work hope there will be more in stock.
http://www.ebay.co.uk/itm/Golden-7-Spring-Vibration-Isolation-Damper-Feet-4-Pcs-...

Another spring worth mentioning is from Townshend Audio.  They have a new Seismic Isolation Pods.  I thought the design looked pretty cool and very well made.

Understanding those charts is above my pay grade...

I finished up my QRD13.  This was a prototype so if does not look great, but it does seem to help my center image.  I think I like it well enough to build a couple proper ones.

Here is my room layout today:

I think what those graphs are saying is that the frequency environment is vast and most "isolation" devices either don't isolate (spikes) or have limited isolation (sorbothane).  Isolation for a given material is everything to the right of its performance line.  The Seismic Load Cell looks like a spring with a Natural Frequency of 2.5 Hz -- hence the spike at that frequency.  As depicted, the spring filters best outside of it's Natural Frequency.  At the Natural Frequency it will enhance vibrations.  2.5 Hz is more of a translation than a vibrations for our purposes and is outside of the audio range.

I'll see if I can produce some graphs from my inner tubes

I`m not the only one that can see a head wearing ear buds or muffs surely. The shaved eye brows are very funny.

Nice layout palomino. Thats organised. Having the listening chair into the room must add to some good prospects.

Quote:
,

Seriously, good music (Doors), comfy chairs, and good company...I almost fell asleep in that room several times just zoning out to the music. Those were hands down the most comfortable chairs I've ever sat in. I just wish I could "trim" the back down to shoulder height to give my ears some space. I totally hear treble spike off leather like that. That's why I subconsciously crane my neck forward when I listen on high-backed chairs. I noticed he had a blanket in there (probably for the wife), and I almost threw it over that headrest portion to damp it some.

I'm not joking when I say I'd find one of those chairs, send it out to a shop to have it chopped down and adjusted.  But I'm nutty like that.  :)

That last shot looks amazing.  :)

Did you wind up using 1/4" fins, or still 1/8"

If the fins get "floppy" in the middle, you can take some 1/8" material and cut slots in it like a comb, and press it over the fins, across the middle of the device.

Something like this -

If you have an air compressor, I have a spray gun that will help out. Brushing these are a huge PITA.

Any updates Palomino?

I looked at my diffuser that I started from scraps last night. I've got about 4 fins of 13 done on it, and got pissed because it wasn't perfect. LOL

I was expecting my shipment of diffusers from PI Audio today, but Fed Ex says they are delayed due to storms...they must go to a weird hub out east or something. So I might have them tomorrow instead.

I've got my table saw cleared off to build stands and maybe be ambitious enough to finish up my one QRD 13 from scraps.