building Iso box for a D1624

[SF Audio]

For those of you who own the D1624, you know it is a bit noisy. Since the panel can be removed and used as a remote control, I'm thinking of building a small box to put the unit in to kill the noise, out of my rack and on the floor somewhere. Perhaps a wood box with acoustic foam, nothing too fancy. If I encase the unit completely, do I run a risk of overheating? How much "air" should the unit have inside a box?

I don't have the choice of moving the unit to far from my other gear, so this seems like a good solution. Any thoughts????

thanks

[skippy]

You need to move a lot of air to properly cool the hard drive: running it inside a static environment will absolutely cause it to overheat, and if you allow air in and out you also allow the noise in and out.

I faced the exact same problem as you. I bought a Raxxess Isorax isolation box, plugged it in, and found out that the damned thing was noisier than the D1624 ( http://homerecording.com/bbs/showthr...threadid=22806 )! So I returned it, and instead I pulled apart the D1624 and modified it to run much quieter- it is relatively easy (hell, it's trivial!) to do. For info on my quieting mods, look here: http://homerecording.com/bbs/showthr...threadid=19703

Hush boxes are really hard to do well: you still need to move air, and the turbulence of the moving air is the direct cause of the noise. The way to do it is to move air at really low velocities, which means having a big hole for it to flow through- so if you don't want to have the noise _also_ come out the big hole, you have to vent it into another room (perhaps through a wall). It was much easier to just address the noise from the unit itself: mine is now somewhat quieter than my Masterlink or the power supply to my Ghost, and it is certainly no problem having it in the control room now.

Hope that helps.

[ausrock]

A while back I decided to get another H/drive for my D160, and rather than pay the ridiculous price Fostex want for their caddies, I purchased a couple of "plain brand" caddies from a computer shop. These have a small inbuilt fan.

When I opened up the D160 I found there was no cooling system for the original H/drive. Skippy, this leads me to think that you were right when you originally said the fan setup you encountered appeared to be an afterthought...............probably Fostex's answer to the advent of the higher speed (7200rpm) drives, which apparently run somewhat hotter than the slower drives..............just to be safe I added additional fans to the caddy housing. It is surprising how warm the air venting from the housing is.

Unfortunately it is now bloody noisey so an iso box is looming on the horizon.

ChrisO

[skippy]

I still think that the solution is to ditch _all_ of those small (>50mm) fans, and use larger fans (60mm and up) that are run at 5-7V instead of the full 12V. The problem is the blade tip speed- the smaller fans have to move their blades that much faster, and that causes the tip vortex noise to move up in frequency- making it *much* more objectionable.

I'd be tempted to pull all the small fans from your new drive carrier, and engineer up a ventilation system with a single, large, slow fan, and some ducting to put the air where you need it. I've never seen the insides of a D160, or I'd sketch up some ideas- I'm sure that it is just different enough from the D1624 to make anything I'd draw up be useless...

If you can exhaust the hot air out the top, put the fan there, and add some intake holes on the bottom. You really want your coolest air to flow across the power supply and the drive- the main board doesn't dissipate that much heat, although it shouldn't be ignored, either. Putting the fan directly above the drive to exhaust into the rack has been the best setup for me, because the unit is directly below all my patchbays in my setup- so I have nothing but space to exhaust into. You could also put some Auralex into the inside of the rack to kill some more of the HF noise bouncing around in there, come to think of it...

Iso boxes are _really_ hard to do well enough to make them worthwhile. But you have to do what you have to do... next time around, I'll build a separate isolated, air conditioned machine room so that all the fans can scream at each other without pissing me off!

[ausrock]

What you are saying about the tip vortex makes perfect sense, and actually making the physical modifications doesn't bother me..............all I have to do is find 5-7 Volts.

Thinking about it, I would seriously consider fitting a couple of reasonable size fans in the top of the housing, so the power supply will be my only concern.

[skippy]

Don't even sweat finding it- just make it for yourself. Easiest way is to put in a 4.5-6V Zener diode in series with the fan, and run the fan-diode combination off the +12V supply that is intended for the disk spindle motor: the current draw will be low enough not to bother a thing. I didn't have any appropriately-rated Zeners when I did mine, so I put 10 regular silicon diodes in series (each dropping 600mV), and run my fan off of the 6V remaining. Diodes work better for this voltage dropping than using a series resistor, because the voltage drop is essentially constant (not a direct function of the current draw, as it is with a resistor). This is important when running the fan at really low speeds, because the startup current is higher than the steady-state current- so using a dropping resistor may cause the fan to not start (it drops too much voltage during the startup surge, and the fan never gets going at all).

Using a string of regular diodes also allowed me to tune the fan operating voltage in 600mV increments, until I got sufficiently quiet operation and still had enough airflow to keep myself happy. Some of the magnetic-levitation fans are very quiet indeed, and can be run right down to 5V with reliable startup behavior...

[lunatic]

I slso have a 1624 and have been looking at quieting options.

Skippy, have you seen these http://www.quietpcusa.com/acb/showde..._ID=27&CATID=4
and what are your thoughts? I put one in my PC with an 80mm fan and love it.


Couldn't we do the same in our 1624s? I imagine it's just a matter of changing the connectors.


Thanks!
Brad

[skippy]

Sure, it would work with a bit of soldering: it's a little but big, but it's not like there is a shortage of space in the box... (;-)

I just used the diodes I had around in the junk box. Anything that reduces the operating voltage of the fan will be good. Just don't go below about 7 volts unless you are very sure that the fan will start reliably.

[lunatic]

Mmm... hot solder.


Thanks Skippy! I appreciate the input.