Cabinet design and isolation planning. Please help.

[Ramdough]

Hello all

This is my first post. I hope to get feedback on my planned audio cabinet.

I have a decent amount of graduate level work and 12 years experience working on damping materials and baffles, but not any experience with what I should or should not do for home audio.

If you help me figure out what I need, I can make it.

This is the project I am contemplating:

I am building a rack (or a few) in a low cabinet to go under my wall hung tv. I plan on putting the cabinet on wheels and using a diy "z" bar for cables to the wall. The back of the cabinet will have a cavity for all of the cables so that the shell of the cabinet will rest against the wall (possibly with a gasket to reduce vibration noise). My center speaker will sit on top of the cabinet and possibly my right and left (if I upgrade to a 9.2 surround). If I don't upgrade, the r/l speakers will sit on their stands. I will have 2 Elan S6 whole house amps, a power conditioner, a system controller, and possibly my AVR in one rack (left side). In the middle I planned on a slide out shelf with a record player on it and possibly a vintage audio receiver/amp (not a rack). The record player and vintage amp are dated probably from the early 70's. I am also contemplating putting them on a shock mounted granite shelf and adding a lid to the cabinet. In that case the speakers may have to move to a shelf on the wall. On the right side, my HTPC, blueray, cable box, cd player, etc would reside. The right side may or may not be rack mounted, it may be just shelves.

So, here comes my questions. What type of vibration suppression would you recommend and where to use it?

Options I am considering:

Build my left side rack, then shock mount it to the cabinet.
Build the left rack into the cabinet (easier).
Leave the turntable on a drawer slide.
Put the vintage turntable and amp on a heavy shelf (granite, lead shot, concrete, or something else) then shock mount the shelf with a flip open lid on cabinet.
Shock mount speakers on cabinet or mount them to the wall.
Build a right side rack, shock mounted or do individual shelves (shock mounted or not?).


Thanks in advance for any guidance.

 

[Swerd]

Welcome to AH!

The primary goal of an audio gear cabinet should be ventilation, not shock isolation. Electronic gear produces heat. Don't trap it inside. Leave the cabinet front and back open. If you give hot air a path to escape while allowing unheated air to enter, you can do this with passive ventilation. Fans may help, but they can also introduce noise and vibration.

The only thing that might benefit from some vibration isolation is the turntable. The greatest source of vibration is, of course, the speakers. So avoid keeping speakers in the same cabinet, or piece of furniture, as the turntable. Avoid generating an acoustic feedback loop where sound from the speakers travels to the tone arm and pick up, and back through the speakers again. This can make a muddy unclear sound to the mid bass.

Heroic anti-vibration measures, such as granite or lead, are probably not needed, but if you avoid acoustic feedback, keep the turntable level, and isolate it from foot step vibration (if you have a wooden floor) you'll be fine.

 

[Ramdough]

Thanks swerd for your feedback.

I did want to enclose my cabinet to hide the cables in the back (eventually going to 36 speakers, plus interconnects, network, and HDMI matrix). Also, I wanted to control dust and noise. My HTPC does make some noise despite me buying upgraded fans. My thought was to put a filtered vent grill on on the wall behind the cabinet to draw air through the back wall (that wall is shared with a hallway behind). I would use very large slow rpm fans and direct the air past my equipment. The exhaust air would be baffled. Alternatively the intake and exhaust could be in the cabinet and both have baffles. I have not decided yet.


My floor is wood glued to concrete, so it foot steps should not be transmitted well.

If I move my speakers off of the cabinet, I would have to use the wall for the center speaker. Do you see any issue with that? From what I have read, floor stands are better.

Thanks again for your help.

 

[Swerd]

As long as you're aware of the heat problem from the start, there are many ways to accomplish adequate ventilation for an electronic gear cabinet. Just remember that hot air rises. Give it a way to escape.

What first triggered my response was your description of a cabinet backed up against the wall behind it with anti-vibration gaskets between it and the wall. That made me think of inadequate ventilation.

If you click on the Photos link in my signature below you can see my set up. Some of those photos show wooden cabinets with a door in front holding the usual assortment of audio gear. I enlarged the cutouts in the back, placed them 3" or 4" away from the wall behind, and rely on a slowly revolving 50" diameter ceiling fan to ventilate the cabinet. A simple test with smoke from an extinguished candle can show the air flow, even at the slowest fan speed.

If I move my speakers off of the cabinet, I would have to use the wall for the center speaker. Do you see any issue with that? From what I have read, floor stands are better.

If you only use the left and right speakers mounted on floor stands while using the turntable, the location of the center speaker will not matter. If you do use the center speaker, something like a layer of dense foam or compressed felt under the speaker might be all you need. Some turntables, depending on their construction, are better isolated from acoustic feedback than others. Trial and error will show you what works.