Room treatments – part 2

In our first go-around on acoustic treatments, we discovered that the importance of several items:

Room acoustics are one of the more important aspects in audio system performance

Bass modes require significant amounts of trapping to have big impacts
There is almost no such thing as too much room treatment, Bass is very hard to manage and ML’s generate a ton of high-frequency energy as well.

Taming High-Frequency modes, especially side wall reflections is important.

As a result of the first round, I saw tremendous improvements in performance and actually reduced the number of electronic corrections required to compensate for room issues.

The sound of the room was noticeably ‘quieter’ and the bass booms were largely gone after the 25 RealTraps products were added to the room.

However, I knew that would not be the end of the line in achieving excellence in this room, as the entire side walls were basically untreated, with just some RPG pro-foam lining the walls in the front, and some Auralex panels along the rear parts of the side walls. The mid-bass and bass performance of these elements was sub-par, so I knew I’d have to remove them and do something better.

But the side walls are one of the most visible elements in a room, and having basic black rectangles hanging off them was not attractive, even to a function over form guy like me (hey, I do have some taste ).

Therefore, while performance was paramount, I also wanted something that would improve the aesthetics of the room as well.

Part of that non-functional look was a reinforcement of the theme embodied in the XStatic name of my theater, which of course features MartinLogan speakers. And as we all know on this forum, one of the distinguishing features of the ML’s are their large ESL panels, and since I had just finished repaneling my Monoliths and an SL3, I had some ‘left-over’ panels I could use in the décor efforts.

Therefore, I decided that the front 13.5’ of my front walls would be covered in a combination of acoustic treatment / decorative feature that supports the ML theme.

To remove any further suspense, here is the final result of that design.

And here is a view of the Right side of the room.
You can see that the new structure features a pair of ESL panels (one from a Monolith and the other from an SL3) with a light source behind them.

These panels also contain treatment material as will be detailed later.

Looks pretty cool, right?

And no surprise, a symmetrical left-side view. The indentation towards the front of the room allows extra space to navigate around the monoliths.

In this shot, we see some of the details of the custom cabinetry that houses the treatments. That’s a single 13.5’ long element that was shop constructed and then installed and finished on-site.

Note the air holes along the top (and there are corresponding ones on the bottom) to allow air pressures to normalize behind the fiberglass panels. This increases their effective low-frequency absorption.

A bit of detail on the end piece ESL panel. This is the SL3 panel forming a nice gentle curved end to the system.

A closer view of the Monolith panel section. Notice the smooth beveled edges flowing into the panel. This allowed keeping the panels frontmost (center) edge aligned with the edge of the structure.

And this view shows the inset we made to allow for easier traversal around the Monoliths.

The coolest thing is that it now looks like there are 9 large ESL panels in the room

Now that you’ve seen the results, how did this come about, and what’s inside that nice-looking structure?

It all started with this sketch of the idea and how it would be implemented, click on the attachment link to download a high-resolution vector-drawing PDF (fully scalable so you can zoom in and maintain resolution).

From the sketch above, we decided to build a 6” deep custom frame that would hold 2” thick OC 705 fiberglass covered in the muslin and cotton batting described in this thread http://www.martinloganowners.com/forum/showthread.php?t=6832

And as that thread showed, we needed to build many, many pieces of varying widths to accommodate the design.

The fiberglass panels are offset from the wall behind them by 3” or so. Then fronted with Guilford of Maine (GOM) fabric that is held in place by one of the secret ingredients of such a cool look, the Fabricmate tracks used to hold in the fabric, allowing us to get it just so, and to change it out in the future if needed.

To prepare for this, my dear wife (Liz) did the research and got their installer kit plus a bunch of test track to ensure we ordered just the right stuff for the install.

I need to stop for a bit and give credit where credit is due, this project would have never happened without the dear spouses engagement and many, many hours of work to make this happen.

I’m a very lucky man to have a partner who will help design and execute these wild projects in the home theater.

The final benefit of her engagement, High WAF

The other player that deserves recognition is the custom woodworking resource we contracted to help develop this project. Don is a real experienced professional who asked tons of questions and did an awesome job of detailing everything out.

This was no cakewalk of an engagement, what with curves, many angles and a set of functional criteria that are uncommon (like no rattles or buzzes allowed). Don executed everything to perfection.

When Don delivered an installed the frames, they looked awesome, with their nicely detailed Aniline dyed dark purple trim (a custom mix made by my wife).

Here’s a shot of Don installing the raw frames.

Some of the detail on these frames is incredible. Here’s what Don did to mount the Monolith panels. He cut contoured mounts and placed them just so that when the Velcro fasteners are attached, the panels just pop into place with no muss or fuss.

The dear wife also worked hard at figuring out which Fabricmate tracks to order and how and where to mount them to obtain the best results with the cloth.
We did not want any visible seams or mount points, and she achieved the goal through some real creative uses of the product.

This was not simple. Neither was the cutting nor mounting to the frame, which she also performed.

Once the many custom sizes of fiberglass were cut and covered, we were able to mount them into the frame and position them right up against the tracks (which offsets them a ½” away from the front cloth.

With the panels mounted into the frame, we were able to move on to the fabric installation.

Here’s a partially inserted fabric section. One uses several specialized tools to insert the fabric into the track, and then it gets trimmed once it’s well-mounted

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The ESL panels were quite fun (not) to disassemble and clean up. Starting with separating the two sides, which was a bear to do. That requires some glue solvents, some strong putty knives and instruments that will cut through rubber-like compounds.

Anyone who thinks ESL panels are delicate things has a rude awakening when you try to disassemble them. Man these suckers are put together well. Even the Mylar was tough to rip out. It’s pretty tough on its own.

The worst part was the removal of all the glues and pieces parts left behind during disassembly. That took some industrial glue and adhesive remover (the kinds that is gel based) to really do the job.
That part is not one I’d ever want to do again.

But, we wound up with four perforated panels that match our existing speaker setup. So it was worth it (or at least I keep telling myself so).

One of the goals was to have these panels ‘glow’ with colored light in a nice even diffuse way. This turned out to be a bit of a challenge (and one of the reasons for the delays in these posts) to get the right materials that would be both diffusive enough and acoustically correct.

The mounts for the panels have fluorescent light mounted in them. The tubes for the fluorescent lights are sheathed in a colored polycarbonate ‘filter’ that give either Purple or a pleasing Blue. But just naked behind the panels, one sees the bulb, not the ‘glow’ we were looking for. So we experimented with many materials, finally settling on an eighth of an inch thick white felt material that is available in widths and lengths suitable for the project. Then it’s just cut to size, spray some light fabric adhesive on the back side of the panel, and presto, a panel with built-in diffuser

So, that’s it folks. It was a heck of a lot of work and some coin as well, but the results both look wonderful and perform to expectations.

The room is now more neutral than ever from a resonance standpoint, and I feel this is what a large set of ML’s need in a room of these proportions.

JonFo said:

The coolest thing is that it now looks like there are 9 large ESL panels in the room

Click to expand...

I was gonna say before I read this - "those panels look so real they look like they should be working"!!

Yup - been watching as you've been posting this - just awesome!

The obvious question is what is the effect sonically... besides just looking completely awesome.

You have now created the ultimate chill out room. And to think I put my used Ascent panels on ebay only a few months ago... with a little lateral thought I COULD have done something similar to this, on a smaller scale.

There is some pretty creative and solid thinking behind all that JonFo, and this is just an awesome post. 100% full marks for effort! Top job on diffusing the lighting too.

One can't help wonder what it would sound like if the wall mounted panels were active! Probably a mess for music but for HT it would follow the ploy of our local cinemas i.e. loads of speakers up the side walls. I'd guess you'd need a lot of absorbtion behind each panels due to wall proximity etc... just a thought not to be taken too seriously.

Excellent.:bowdown:

Money well spent in the persuit of sonic nirvana, escape from reality, idiotic politics and the hardships of modern day living. Enjoy it. I am sure you will.

Justin

User211 said:

...
The obvious question is what is the effect sonically... besides just looking completely awesome.

You have now created the ultimate chill out room. And to think I put my used Ascent panels on ebay only a few months ago... with a little lateral thought I COULD have done something similar to this, on a smaller scale.

There is some pretty creative and solid thinking behind all that JonFo, and this is just an awesome post. 100% full marks for effort! Top job on diffusing the lighting too.

Excellent.:bowdown:

Justin

Click to expand...

Thanks Justin, really appreciate it.

I'll be posting full measuremnts and other objective data next week. I'll throw in some opinion in for good measure as well