Porch Enclosure

Suppose you have a machine which has a very strong magnet inside. You have some computer disks in the room and, although you think they are far away enough from the magnet to be safe, you don’t want to take any risks. What material would be appropriate for building a magnetic shielding enclosure?

A) aluminum.
B) plastic.
C) iron.
D) copper.

We won’t do your homework for you dude.

THESE ARE THE DETAILS OF THE SPEAKERS AND THE AMP p.s whats better 2 ohm speakers or 4 ohm speakers ?? i want more bass!
Description Value of the speakers
Size 12"
Impedance 2-Ohm x 2
Power Handling 500 RMS
1000 Peak
Sensitivity 87 dB
Motor Size 102 oz. double stacked
Voice Coil Diameter 2.5" aluminum
Speaker Connector Dual 8 AWG compression
Mounting Depth 6.375"
Rec. Sealed Enclosure 0.75 cu. ft.
21.24 liters
Rec. Vented Enclosure 1.75 cu. ft.
49.56 liters
Tuning Frequency (vented) 37 Hz
Shipping Weight 25.2 Lbs.
(11.4 Kg.)

Audiobahn A16000V
A16000V Audiobahn Mono Block Amplifier
Double Sided Glass Epoxy Circuit Board
High Gloss Chrome Plated Finish
Variable High/Low Pass Crossover
Variable Low Pass Crossover: 50 - 120 Hz
Variable Subsonic Filter: 20 - 50 Hz
Bass Boost 0- +18dB
Phase Shift Switch: 0 - 180 degrees
2 Ohm Mono Stable
MOSFET Power Supply
1x 1600W RMS @ 2 Ohms
1x 800W RMS @ 4 Ohms
Fuse Ratings: 40A x 2

As the above stated, for 3 ohms and about 1200 watts RMS wire like so:

http://i81.photobucket.com/albums/j230/sparky3489/TRI-DVC-PARSER.jpg

Here is some info on enclosures (and other tips):

http://spkrbox1.spaces.live.com

I was looking at the specs for the 13" Macbook Pro and the newest white macbook. They both have the same processor, same memory, same video card, same battery. The 13" macbook pro has SD slot and Firewire and the aluminum enclosure is probably more durable than the polycarbonate one, but the whitebook has a bigger hard drive and costs $200 less.

So, why so much more demand for the 13" Macbook Pro than the white macbook?

because Mac users follow blindly… some blogger wrote about how great the 13mbpro is, and now everybody HAS TO HAVE ONE, OMFG!

I have an internal drive that I made into an external one by an enclosure. The enclosure itself is aluminum. I try to put a fan right over it in order to keep the drive very healthy. Is it going to be a counteracting force to the drive’s spin if I put a PC fan right over it? I notice sometimes a transfer speed decrease when I put a fan over it.
Edit:
I actually didn’t "see" it decrease. I was using WBFS manager to transfer Wii iso’s to my external drive, and it didn’t show me a transfer speed. I just guessed by my sense of time.

Electric motors work by rotating a coil of wire in an electric feild. So i guess in theory that that field could interfere with another motors field.

In practice though I think the strength of the field reduces in proportion of the distance squared. And as it was a very weak field in the first palce i think its unlikely.

Run a few HDTune benchmarks without the fan, then put a fan on top and run them again. If it is causing a problem you should only need to move them apart a tiny bit for the interference to stop. Just try a few benchmarks until your sure its ok.

I PURCHASED THE SATA $ IDE 3.5" HARD DRIVE TP USB 2.0 AND e-SATA ALUMINUM ENCLOSURE CASE ABOUT 2 YEARS AGO AND I HAD A PROBLEM.
I TRY TO ACCESS I FILE IN THE HARDRIVE BUT IT TELLS ME THAT I DONT HAVE PREMISSION TO ACCESS THE FOLDER. HOW CAN I ACCESS THE FOLDER WITH NO PROBLEMS?

It depends on the operating system and it’s security measures. On Windows 2000/XP/2003/Vista/7 you may just need to log in as an administrator and change the permissions of the drive or folder by right clicking and going to properties. There would be the properties tab.

If you are using Linux, you’d have to log into root and possibly unmount and remount the disk so you have permission or use chown and/or chmod on the directories and files.

Case ( [New !!] Coolermaster Airbrushed Stacker 830 Gaming Case w/420W Power Supply Blue Flame )
Case Lighting ( Cold Cathode Neon Light Blue )
Power Supply ( 1250 Watt — CoolerMaster Real Power Pro Power Supply Quad SLI Ready )
Processor ( [=== Quad Core ===] Intel Core 2 Extreme Quad-Core Processor QX9770 (4x 3.2GHz/12MB L2 Cache/1600FSB) Free 4GB Pen Drive )
Free Software/Game ( Free Game - [Halo 2] must purchase with Microsoft Windows Vista operation system )
Processor Cooling ( ULTRA ChillTec Thermo Electric CPU Cooler a solid-state active heat pump capable of transferring heat from one side of the device to the other )
Motherboard ( Asus P5E3 Premium/WiFi-AP @n Intel X48 CrossFire Chipset w/7.1 Sound, Gb LAN, S-ATA Raid, USB 2.0, IEEE-1394, PCI-E MB )
Memory ( 8 GB [2 GB X4] DDR3-1333 PC3 10666 Memory Module )
Video Card ( [New !!!] 2x NVIDIA GeForce GTX 280 1GB w/DVI TV Out Video - running SLI mode )
Video Card Brand ( === High Performance === eVGA Brand Video Cards [SLI enabled] Powered by NVIDIA )
Hard Drive ( 1 TB HARD DRIVE [Serial-ATA-II, 3Gb, 7200 RPM, 32M Cache] )
2nd Hard Drive ( None )
External Hard Drives [USB 2.0/eSATA] ( None )
CD/DVD Drive ( [** Special !!! ***] Sony Optiarc BR-5100S 2X Blu-Ray High Definition DVD Drive )
CD-RW/DVD-RW Drive ( [** Special !!! ***] Sony Optiarc BR-5100S 2X Blu-Ray High Definition DVD Drive )
Sound Card ( Creative Lab Sound Blaster X-Fi Titanium Fatal1ty Champion Series )
Speaker System ( [Black] Logitech X-540 5.1 Surround Speakers Subwoofer )
Network Card ( Killer M1- Online Gaming Accelerator - w/ 400Mhz Network Processing Unit Lag & Latency Reduction Technology )
Floppy Drive ( Mitsumi 1.44 MB Internal Floppy Drive Beige )
Monitor ( LCD-TV Monitor Viewsonic 26" Widescreen LCD TV w/Dolby Digital Sound [N2635w] )
2nd Monitor ( None )
Keyboard ( Combo: Logitech Cordless Desktop MX3200 Laser (MX3200 Cordless Keyboard MX600 Cordless Laser Mouse) Black )
Mouse ( None )
USB 2.0 Accessories ( [USB 2.0] External Super Slim Hard Drive — 320 GB 5400rpm with Enclosure )
USB 2.0 Accessories ( [USB 2.0] External Super Slim Hard Drive — 250 GB 5400rpm with Enclosure )
USB 2.0 Accessories ( [USB 2.0] External Super Slim Hard Drive — 160 GB 5400rpm with Enclosure )
USB 2.0 Accessories ( [USB 2.0] External Super Slim Hard Drive — 120 GB 5400rpm with Enclosure )
USB 2.0 Accessories ( [USB 2.0] External Super Slim Hard Drive — 80 GB 5400rpm with Enclosure )
USB 2.0 Accessories ( [USB] XION XON-SAHDCB-USB SATA HDD to USB 2.0 Dock Station Mounting HDD within seconds and fit both 2.5” and 3.5” SATA HDD to USB 2.0 of your PC )
USB 2.0 Accessories ( [USB] Numerical Keypad )
USB 2.0 Accessories ( Add External USB 2.0 Hub (4x USB 2.0 Ports) )
USB 2.0 Accessories ( Built-in USB 2.0 Ports )
Meter Display ( NZXT Sentry LX Aluminum Fan Control, Clock, and Temperature LCD Display )
Flash Media Reader/Writer ( External 12-In-1 USB Flash Media Card Reader/Writer )
Operation System ( Microsoft Windows Vista Ultimate [Free 60-Day !!!] Microsoft Office 2007(Word, Excel, Outlook, PowerPoint, Access ….) 64-Bit )
Media Center Remote Control & TV Tuner ( TV Tuner with FM Stereo Remote Control and Receiver MS Media Center IR Wireless Keyboard (watch and record TV on your PC) )
Additional Software ( MS Office 2007 Professional Edition )
USB Flash Drive ( None )
MP3 Player ( None )
TV Tuner ( [USB 2.0] External TV-Tuner w/Remote Control Watch TV from your PC/notebook with the USB 2.0 tuner )
Video Camera ( Logitech QuickCam Pro 9000 2.0MP USB Interface WebCam )
Headset ( === Gaming Headset === Zalman 5.1 Channel ZM-RS6F M Headset w/Mic )
Power Protection ( Opti-UPS VS575C Battery Back-up UPS )
External Wireless Network Adapter ( [Special !!!] Wireless 802.11g 54Mbps PCI Adapter )
Warranty ( Warranty Service Standard 3-Year Limited Warranty Lifetime Technical Support )
Rush Service ( Rush Service Fee (not shipping fee) No Rush, Ship Out in 5~10 Business Days )

What you think of specs ^_^

Too much text.

how much memory would the macbook pro have.
On the site to buy it, it says

* Intel Core 2 Duo
* 4GB Memory
* Precision aluminum unibody enclosure
* 250GB hard drive
* Built in 7 hour battery
* NVIDIA GeForce 9400M graphics

And I was woundering what the memory was.
Would it be only 4 gb
or 250 gb ?

It does not mention the ram anywere so i was thinking that the 4gb memory was just the ram memory.

250GB

This is the white one:
http://store.apple.com/us/browse/home/shop_mac/family/macbook/?aid=AIC-WWW-NAUS-K2-BYO-WHICHMAC-MACBOOK-13-INCH

And the aluminum one (not a macbook pro), which is refurbished:
http://store.apple.com/us/product/FB990LL/A?mco=MTA4MzIzMzA

I would only be using it to write papers, play music, play Sims, etc.
Just last week, I decided that the aluminum one might be better, but since the new white macbook with the unibody enclosure just came out, I’ve been having second thoughts.

I am so happy that I got my first mac yesterday, and I purchased MacBook Pro!!! It has the aluminium casing, a black illuminated keyboard. It has a smaller HDD, but you can get a portable one. This is definitely the best laptop! Plus, i am typing so well on this keyboard. H but this is your decision but I recommend this. P.S. Watch some videos of MacBooks on YouTube.

Should I get the new white MacBook that comes standard with 2gbs of ram and 250gb hdd, it has the new 7-hour battery, glass trackpad, but it lacks an sd slot and FireWire, but I don’t use FireWire but the lack of sd slot is important. And there’s the refurb MacBook pro that has all the features above, ony it has an edge to edge screen, a black keyboard and of course the aluminium enclosure. But it has 2gb of ddr3 Ram, and a 160GB HDD. So the only thing that’s pulling me towards the MacBook pro is the sd slot. Which should I choose? Thanks!
Btw, they are both $999.

I have bought several refurbs from Apple recently with no bad experiences. The MacBook pro may have a smaller HDD, but considering the falling price of SD cards for the slot (bonus storage when needed) and the power of a solid-state HD as a future upgrade, I would lean towards the Pro. The black keyboard will need fewer cleanings to look nice and the resale is likely to be higher in several years for the Pro.

I have a power supply heat sink that is directly coupled to an aluminum enclosure. It also creates a ground path. The Heat sink is simply an aluminum sheet metal bracket. Black anodizing seem to be the norm for heat sink finishes. But it seem to create some electrical resistance. Is there a super finish that will help with corrosion yet be electrically conductive, and help to dissipate heat.

Uncoated aluminum and aluminum alloys react with air forming a mostly invisible layer of aluminum oxide, which is electrically non-conductive. So even uncoated heat sinks have the electrical resistance problem.

The usual way of handling this is to let the (metal) fasteners make the electrical connection between the heat sink and the enclosure, or between the transistor case and the heat sink. A threaded hole makes ample contact, and a (captive) star lockwasher under the screw head will bite through any coating. That frees you to select any coating or nature finish you desire.

I don’t think that a coating affects the the rate of heat transfer to air significantly. Surface area is the main controlling variable.

I think the coating will have little impact on heat transfer through conduction. Use of a thermal grease and/or thermally-conductive pad for coupling the heat source to the heat sink will overcome minor surface roughness.