DIY Audio Rack [*fail*]


Seen a few discussions on this topic and wanted to chime in with my experience. A recent amp upgrade necessitated a change from the "Solid Steel" rack I was using. New amp is deeper and taller so I needed a solution to provide deeper shelves and more clearance for ventilation. Didn't see a lot of offerings that were aesthetically appealing enough to motivate me to immediately bust open my wallet, and a few months earlier I built a "live edge" bar height table to accommodate extra seating in my listening room. The table project was fun and turned out very decent and provided the form and function I was looking for. With all this in mind I thought it would make sense to maintain a consistent look and build a rack using the same materials. Form factor of the Solid Steel rack is 3 shelves in 2 columns accommodating 6 components. I was keen on lowering the profile of the new rack as it is situated in front of an 8' casement window with a low sill so I built it using two shelves which are 65" wide to accommodate the width of 3 standard components. 
Materials used for the table and new rack are 2" square steel tubing that I had fabricated by a local welding shop. The shelves are made from 2" thick live edge pine that is milled/finished to ~1 3/4" thickness. I had concerns using pine, but after working with it I prior, it felt heavy and solid and I thought it would have the density to not negatively effect the sound in the room. The rack is located on the front wall between the speakers so I thought that by lowering the profile, there was an outside chance I might even get better sound. Lastly, when I assembled the rack, I isolated the shelves from the frame with 1" wide by 1/4" thick neoprene tape. I also used rubber washers between the screws and the frame so  the shelves and the steel frame are isolated from one another.
Once I got the rack assembled I was more than pleased with the look. I was seriously chomping at the bit to get it situated in the room with components installed but didn't right away because I really enjoyed just looking at the finished product. I recruited my son to help me move it and was really encouraged as the thing is a beast and weighs a lot. 
I installed components into the new rack, powered everything on and gave it about 30 minutes before I queued up the first song. I think I was still interested in how great it all looked when the music started but it didn't take more than several seconds to realize something had changed and I don't mean just a little. It was like someone put a blanket over each of my speakers. It seems that aside from building a fine looking rack, somehow I also succeeded in building a broadband attenuator that does an awesome job of damping most of the audio spectrum in my room and is particularly harsh on low and mid frequencies. Of course as this happened I shut everything down and rechecked and re-seated all my connections which changed nothing.
I've been super busy since completing this project but in the coming weeks will start to systematically deconstruct the setup to better understand the culprit(s). I am reasonably sure the pine shelving is at least part of it but am interested to see if the isolation technique I used is also damping the sound somehow? I phoned one of the rack companies that advertises a lot here on A'gon and a gentleman (forgot his name) was kind enough to answer some questions for me and mentioned that the coupling technique I used could be a major offender and that there are different schools of thought for when to isolate and when to couple directly. While I am going through this exercise I'll also experiment with moving my components (or most of them) from the front wall to an alternative place in the room. 
In the end I just wanted to share the experience with others that might be considering a similar effort and to say that there is much more to this than meets the eye. I didn't realize how much material, construction technique and perhaps even form factor (size and shape) can all make a dramatic difference. Since all of this transpired I've read a bunch of reviews on racks and many of them comment on the sound of the rack....I probably would have called BS on this before doing this project but now I am a true believer.
128x128chilehed
Hi Michael,
I can remove the damping material easily enough and will give that a try.
I got the pine slabs from a local mill and have seen no movement (expansion / contraction). The fellow I bought them from told me they were dry and it seems he was right. I live in the northeast so we get some pretty wild swings in humidity. The original boards were 2" thick and I had them surface planed and then I used a palm sander with 60, 120 and 220 grit sandpaper. I finished the boards with Minwax stain then Minwax Helmsman polyurethane (3 coats). 
Thanks for the feedback and advice.

Hi Chilehed

Yep after the dampening is gone you should give another report. And from there I'd be happy to help.

220 is going to close the pores so the poly isn't going to soak in as much but with pine you still might be ok (will just take longer to cure). A dehumidifier will help.

I do my pine in the desert so I start off super dry, and then cure it a long time before I start my sanding and coating. After I cure the wood it is about 1/3 the weight of when it was at the lumberyard.

But, that's not where you are at, so your going to need to be patient as the 3 coats is going to take a long time cure for you.

After the dampening is gone (be sure to sand and refinish where the dampening was) your still going to hear a cloudy sound. In time that will clean up. Your also going to want to look at what type of feet your going to want to use under your components.

What components are you using and I can make some recommendations for you when tuning in the transfer.

I had homes in Ohio and NY NY, so I'm pretty up on your curing area.


have a good weekend


mg

Hi Michael- Nice to see you posting here on the forums!

Would brass cones help if used below electronic components to "decouple" ?


David Lynch

@chilehed
I did improve things by putting three granite sample blocks under the turntable and tube preamp. You don’t say what gear you are using so not sure how it will effect things. You can check out some of my pics in Systems.

Hi David, nice to see you. Hope all is well!

Brass is one of my favorite materials used sparingly, as you know. Systems can OD on brass pretty easy, that’s why I do a blend of materials under components. The MTD was designed to get rid of the upward shift caused by other cones and provide a better transfer. My MTD’s (mechanical transfer device) come in different shapes, designs and sizes to work with both old and modern component designs. I’m not saying cones have run their course, but the more detail folks are designing in their products the more squeezed the upper harmonics become causing clustering at certain ranges. Most cones amplify this. However there’s a new kid on the Block. The LTR Blocks are the latest greatest hit makers. The LTR Block is bringing music back into the game.

After moving to the desert in 2004, I found I could make an amazing tuning device that I was not privy to before. The voiced Low Tone Redwood Blocks changed my view of cones. Not just brass cones but any cone. Now I use one or two cones for flavoring when wanted but most of my system (systems) have become more in-tune. And a big plus is the voicing adjustability.

coupling vs decoupling

HEA sometimes steps on it’s own tongue and for years has been using the term "decoupling". After doing tests after tests by myself and many others I never found a case, in the audio range, where the components became decoupled from the surface below or above. In fact the opposite is true. When you set something on something else you are coupling not decoupling. Decoupling would be when you defeat gravity.

I don’t know if NASA still gives the tour but they use to have an anti-gravity chamber where you could go in and "decouple" yourself from the ground. This was done with air pressure pushing up. They also had other cool tricks using magnetic fields. But, in our hobby we don’t use those devices, and bladders, springs (including my Harmonic Spring), cones, rubber or any device subject to gravity and weight are in reality "coupling". Of course audiophile home brew experts will argue this, but it doesn’t change the fact that when you touch something with something else there is an interaction.

Anyway, I’m sure that’s more than you asked for, but you know how these threads are "say too little say too much" LOL.

again great to see you

Michael Green