When I got this audio cabinet about 8 years ago I put 3 fans in it. I got the best fans that I could find to reduce the hum that fans all make – Vantec Stealth 5″, and a Vantec Stealth 3″ for the center bay. There is a small transformer hooked up to the Aux power of the receiver so that the fans turn on whenever the receiver is on.

Here is what I came up with only now after all these years to quiet the fans:

The original scheme had the fans mounted on a piece of 1/2″ plywood and that is isolated from the very thin cabinet back with 4 screws through grommets. Notice the slot in the plate and cabinet back for cable access. While this doesn’t seal the fan to the cabinet, the cooling does not suffer and cable access is greatly simplified.

See the next photo for the grommets:

The grommets hold the plywood and fan away from the back of the cabinet, but the screw still allows hum to conduct from the fan plate to the cabinet back, which acts like a sound board. The hum was not very annoying, but you could hear it.

In the past the fans were screwed directly to the 1/2″ plywood plate. But the recent idea, which totally deadens the hum, is to isolate the fans from the cabinet back with thin sheets of foam. This is shown in detail in the next photo:

The new scheme adds two thin – door skin 1/8″ plywood – ears to the fan. Then two sheets of open celled foam is glued between these ears and the plywood plate. Using open-cell foam allows the use of wood glue to glue the foam to the wood. Elmer’s or TightBond both work fine. Closed cell foam might work as well if it is rough so the glue can work. Of course you can use contact cement as well to glue the foam. You should pick as swishy a foam as you can find. stiff foam obviously will conduct more vibrations to the cabinet back. Using the foam, there is no solid coupling between the fan and the back of the cabinet. So the sound is completely deadened. It would no longer be necessary to use the grommets at this point. The 1/2″ plywood plate could be attached directly to the cabinet back. If I were doing a new design, I would use thin plywood instead of the 1/2 plywood since the weight of that mounting no longer contributes to the sound isolation.

Finally!! No fan hum!!

Good luck and I hope this gives you an idea if you have a similar problem,

enjoy,

windy

After more than 15 years, my Audio Research AR9 speakers are toast. Actually the speakers are fine, the only problem is that the urethane driver baffle has rotted out. Of course all speakers of this age do that. I’ve replaced the baffle a while ago on my Infinity Powered 10″ Subwoofer. It turns out that you can buy the baffles on the web for any size driver and glue them on yourself. But it’s a pain in the behind to do this for 1 driver, let alone 4 drivers, so I’m going to retire my old AR9’s in favor of a pair of new Polk Audio Monitor 60’s.

Here is the AR9 that bit the dust. Took me a while to figure out how to pull its pants down, so to speak, so I could see the drivers.

Notice that the lower driver’s baffle has completely rotted away. Apparently the oxygen gets to the urethane and turns it into mush.

Here are some closeups.

and a normal driver – rotted but not yet completely fragged.

And here is what the whole setup looks like:

Not sure yet whether I’ll put the Polks on the top of the plywood boxes or not.

- windy

In a completely different direction, its time for a new satellite TV service [Dish] and the DVR requires a phone connection – Dish charges another $5 a month if there’s no connection. They are probably harvesting viewing habits with the phone line, in addition to allowing PPV ordering.

These two issues have created a project to wire a set of CAT5 cables around the house. The rear of the house has no crawl space and no attic, so the wiring is external on the outside of the house. The best and simplest method appears to be to use outdoor CAT5 cable with UV coating and silicon gel for direct burial. Oregon is wet, so while not used for direct burial, the cable is likely to be wet for much of the year.

The connections were made using Leviton Quickport wall boxes and outlet plates.

The CAT5 connection goes straight from an office port around the house to a port on the wall in the back room. The phone connection is daisy chained from a port in the office to pick up the phone, to a port in the den, another port behind the entertainment center in the den and around to the back room with the CAT5 connection. Daisy chained connections are not normally used for phones, but 4 connections are required, and it seems unreasonable to wire 4 separate wires around the house. Of course daisy chain is not possible for CAT5 Ethernet.

After some experimentation, it seems that it is not possible to directly attach two cables to a QuickPort connector, and it’s not reasonable to take a single cable directly through a connector. So, a daisy chain point requires 6 3-way splices. All 6 wires were connected to the RJ-11 phone connectors, even though only 2 are used for the phone line.

These are little buttons that splice the wire without stripping. Stick the wires into the three openings and mash the button with a pair of pliers. The splice is filled with silicon gel, so the splice is waterproof. In this application, the splices are in the mounting boxes. One of the splices failed during the installation with one of the connections being intermittant.

The direct burial cable is filled with silicon gel, which makes it a sticky mess to work with. The gel does not come off with soap and water, but a trick was discovered. Wipe the wires with a paper towel wet with olive oil and the gel wipes off easily. Also olive oil removes the gel from hands and other items. Of course, soap and water easily removes olive oil when the job is done. Olive oil is a lot less smelly than paint thinner or other solvents.

The job is done, and all is working just fine.

Cheers…

I needed a printer cabinet. So I slapped one together from stuff I had around the house. 1/2″ OSB and 1/4″ oak plywood. I may get around to painting it, but for now it’s a natural. Click on the picture for a larger view.

Construction is routed dados for shelves with glue and staples.