The purpose of this thread is to promote an exchange of ideas about the concept of creating a PSU channel, best materials, the construction of an effective noise barrier in the channel, and other related ideas.

The concept of making a fresh air channel from a 5.25" bay (usually the top one) to the PSU was introduced by MikeC; he has posted on this topic in a number of different threads. The system I am building is outlined here. This thread includes two or three posts by MikeC giving me instruction on how to make a fresh air channel for my PSU. The concept is illustrated in article "Quiet MP Dual-CPU Workstation" by Leo Quan here. As I have searched the forums I have encountered a number (at least half-a-dozen) of posts by people who have constructed a PSU channel and reported favorably on the result.

This concept of creating a PSU channel applies to PSUs that exaust out the back and have their air intake on the opposite side, thus in line with the top 5.25 bays, such as Seasonic Super Silencer PSU line.

BTX, the next PC computer standard, coming in 2004 uses channels for cooling, also referred to as inline cooling. MikeC posted some pictures of some BTX prototypes here. And I read a post that said Apple is already using the concept of cooling in channels. So, it appears this idea warrants our consideration.

Anyway, I am in the process of creating a PSU channel, but I was fuzzy on how to create a noise barrier in my channel. The purpose of the noise barrier is to block noise without blocking air flow. Then yesterday I came across a template for a commerical PSU Muffler $30 here that shows a noise barrier.

After sleeping on the concept presented in the template, I woke up with a clear idea of how to go about creating an effective noise barrier that suits my air flow design. I'll explain my new idea below.

1) The top two bays are used for my PSU channel. A thick card board forms the bottom of the channel, extended from the bottom of the 2nd bay to the edge of the bottom of the PSU.

2) I removed the plastic cover on top 5.25 inch drive bay. I will replace it with a piece of light gray foam, it is porous, I can breath/blow though this foam easily. The appearance then is much like a speaker front. MikeC tells that he like to make a grille out of modder's mesh, that can be painted to match the case if desired.

3) I then cut material to fit the top and bottom and sides of my channel. The material I am using is a closed cell foam that is about 5/8" thick. I suspect that this may not be the best material to use. At this point my focus is on building a channel that provides adequate airflow with an effective noise barrier using material on hand. If I come up with better material I can take it apart and use it as a pattern.

4) The final step is to make a noise barrier. The one I made extends from the top of the channel to a little bit below the bottom of the first bay. This way the air must go under the noise barrier and up to the 1st bay, and the noise will be blocked, ie will not be able to escape the channel, at least this is the theory.

I am interested in learning what materials others have used and would recommend. Is the white foam packing materials OK to use? I have two kinds of this stuff, one is a flexible slightly squishy closed cell foam that feels kinds of plasticy, don't know how best to describe it. The other is white styrofoam, if you bend it it will break a part. Both of these are close cell foam.

Layering. A layer of closed-cell foam (you cannot breathe/blow thorough it) foam on the bottom, with a layer of open-cell foam (you can breathe/blow thorough it) as a top layer. Would this be good, or is this just not the right material?

I learned that my RMA'd motherboard was sent out today, so I want to finish my PSU channel before it arrives.

Thanks to all, and especially to MikeC for providing this wonderful forum,
Lilla

*Editted* 25Nov2003 to omit the claim that BTX cases will have the power supply at the bottom of the case.

that's an amazingly simple concept that i'm surprised i hadn't heard of before. already you can tell that it's going to work pretty well, and if anything, it'll improve the airflow inside the main part of the case as well which would be less one useless air pocket in the 5 1/4" drive bay area.

i'm thinking if you seal it off sufficiently then you probably won't need to add another fan to the channel - the PSU fan would suffice. alternatively, you could remove the PSU fan and attach it to the inside-side of the PSU. but given how the front would be more open, that might actually increase noise a bit.

let us know how it goes. and we want photos!!!

Good topic Lilla.
For the channel, I used a sheet of black "Foam Board" purchased from Staples for Cdn$7. It's like "thick" bristol board with foam inside. It's used for storyboarding. A single sheet is more than enough to make ducts for 2 PC's. It cuts easily with a utility knife. My duct has 4 pieces (bottom, top, 2 sides). Friction between the pieces holds them solidly in the case. The front of the duct is the height of the top drive bay. The back of the duct is the height and width of the PSU. The sides are shaped to align to the expansion in duct height. The sides and top piece are flat. The bottom piece has appropriate bends, so there are no gaps along the sides. Only a bit of trimming to work around the wiring where it exits the PSU at the bottom edge of the duct. I considered how I might insert sound baffles/noise barrier inside the duct when I was planning it - but after installing the duct, haven't seen this as a priority. I don't notice significant noise coming from the front of the PC. I'm interested to learn how the barrier works for you.

Instead of Modder's mesh, I found a replacement Speaker cover (fine perforated steel mesh - painted black, in a plastic frame) at a local Radio Shack (Cdn$10). I popped out the mesh and flattened it with a rubber mallet. I cut and bent the mesh to form a press fit replacement for the upper bezel panel; It didn't need repainting. Good airflow - contrasts nicely against the generic ivory case.

Styrofoam may not be a good idea - some types I have appear to break down after a while and get real brittle. I don't think little bits of foam flying into the PSU will do it much good.

A suggestion on material : perhaps foamed melamine boards from McMaster-Carr?

As for the noise barrier, I can think of two alternatives :

1) Two noise blocks, one extending 5/8 of the way down from the top, another extending 5/8 of the way up from the bottom.

2) Something similar to BlueFront's LanBoy fan muffler : one piece of foam with 4 holes at the corners, and another piece of foam with a hole in the center, the two pieces placed 1/3 and 2/3 along the length of the channel.

All this is aimed at eliminating a straight line from the PSU to the intake. Using foamed melamine might have the additional advantage of noise absorption.

Disclaimer : These are just ideas off the top of my head - I've not actually tried any of them.

Found a link here describing a PSU tunnel in a Sonata with pictures. Might be helpful.

Methinks I will try to make a tunnel, as soon as I have some spare time

Ive been looking into the BTX standard a little (get nervous about buying a new case when there's a new standard around the corner ), but cannot see any mention of the case layout you discuss.

Form Factors has the specs here (PDF) and they are focused on motherboard layout, removal of legacy connections, provisions for PCI-Express etc... but not case layout.

Am I missing something here?

The articles and specs I've seen also say that BTX will use the same ATX power connector, so we can continue to use existing power supplies (although S-ATA power provision will be mandatory).

Don't get me wrong, I think the idea of a separate channel for the PSU at the bottom of the case is a great idea. Surely this could be done today by an enterprising case developer? Might just need longer PSU cables?

However I dont think Ill sacrifice 2 x 5.25" slots at the top of my case at the moment - Im looking to have a door to seal off noise from the optical drives anyway...

But correct me if Im wrong about the BTX stuff!

Good luck with the project and share them photos later!

/bfg

chylld, I'll take some photos, I can borrow my brother's digital camera. I may not get them posted right away however, as the motherboard is scheduled to arrive tomorrow, and my priority will be getting things operational. This is my first build, so I go kind of slow, lots of stuff for me to figure out...



Lenny, good point on the styrofoam, how material ages, smells when hot, flammability, lots to consider. I am not using any styrofoam.

OK, I am pretty much done with the channel. I used the flexible plasticy closed cell foam material (not styrofoam). I burnt a small piece of it to see what would happen, it melts and gives off a bad smell, but it did not flame, at least the tiny piece did not.

I'm going to research the alternate material that Lenny mentioned, and the other that Paul mentioned, or maybe they are the same?

All the pieces are cut and pressed into place, the 5/8" material that I used has good body and this worked well.

There is a 1/4" foam piece that covers the cardboard bottom of the channel and butts up against the bottom edge of the PSU. This piece of foam is glued to the cardboard. I didn't use the 5/8" material here as would have covered up part of the intake holes on the PSU.

I put a piece of foam behind the plastic cover that is on the 2nd 5.25" drive bay. My combo DVD/CDRW drive is in the 3rd 5.25" bay. The bottom of the channel is cardboard (back of yellow paper notepad), one end of the cardboard bottom rests on the end of the combo drive. The other end butts up against the bottom edge of the PSU, it does not go underneath the PSU at all. There is a small hole in the cardboard+foam channel bottom that allows the PSU wires to extend to the lower compartment where the motherboard is.

This morning I made a change to the noise barrier. I switched to Lenny's barrier #1 method, placing the two barriers at the 1/3 and 2/3 locations recommended in barrier method #2.

Anyway, I'm happy with my PSU channel for now. I figure I can use it, and see what it needs. Maybe I'll decide it is good enough.

Thanks for the great ideas. I'll post back to this thread and let you know how my channel works when I get the system up and running. I'll continue to monitor this thread as my design is flexible.

Lilla

Somewhere I saw a picture of a BTX prototype case with the PSU at the bottom of the case, but that does not mean that it is a requirement of BTX, so I reworded my initial post. Thanks for point out my mistake so I could correct it. Sorry for any confusion.

I corrected my initial post to say that the BTX standard will use inline cooling, ie cooling in channels. And, in my initial post I added a link to BTX prototypes pictures posted by MikeC.

Thanks,
Lilla

Hope you didn't take offense Lilla - none was meant...

I was really hoping you would prove me wrong as I believe the idea has great merit and probably should be part of the BTX specs!!

The ATX specs included requirements to have the PSU above the CPU to act as the case fan. The fact that everyone now has at least one dedicated case fan (you extrem fanless guys excluded!) means the PSU doesnt need to be on top - in fact probably shouldn't be...

Anyway, I still think a manufacturer could build a case like the one you mention, with a separate channel at the bottom of the case for the PSU, with the ATX or BTX specs... it should be doable...

let us know how the channel works out!

/bfg

The PSU channel might also be good for cooling 1 or 2 suspended harddrives!?

I started a BTX thread a while back and one of the posts in that thread has a link to a bunch of Intel pdfs (including drawings) of the BTX layout.

No offense taken.

I looked at the link that Ralf posted with the slideshow on BTX chassis layout, and the drawing showed the PSU at the top in it's normal position in the BTX tower case.

I'm glad you asked me to support that claim, because my statement was wrong and worse, my *mind* was wrong. Now both have been updated and this is a good thing.

Lilla

For those who wanted to see pictures of my PSU channel, well I took pictures today and I got them uploaded. I took pictures of my Evercase E4252 case preparation, which includes pictures of the PSU channel.

You can see my pictures here

I welcome any comments, ideas, thoughts, etc.

Lilla

are the HDDs isolated?

Seal off any unwanted intakes if you haven't already.

You could add a slit by the CPU to allow air in.

If you really want to get serious, water cool! Kool n Quiet has an enormous radiator that can supposedly passively cool any CPU. silentmaxx and prob. others offer a water cooled PSU!)

Regarding the ideal case, I think if I ever built a case w/fanless PSU I'd put the PSU on the bottom as well, it'd run a lot cooler that way

Very nice start to your project. I'll bet it's dead silent in it's current configuration.

Maybe someday you'll actually have a mobo to put inside the case so you can complete your system and see how well your PSU channel works.

Yes, they are installed using rubber grommets from the hardware store, and using homemade shoulder bolts. I will take a close up picture of the hard drive mounting and add it to my online build photos.



Good idea, I haven't done that yet.



Actually, this case has air intake holes in the left panel opposite the CPU, and also a cute little green fan to push air to the CPU. I removed the green fan, and closed off the side air intake holes to encourage directed air flow. I did this because MikeC has posted that this technique works well in this particular case. I will add a picture of this too.



Thanks Ralf, and yes it is DEAD silent without a motherboard. Dang it!

Ralf knows the story of my motherboard woes well as he has been offering me his advise which has been greatly appreciated.

But, for those who haven't been following my tale of motherboard woes in my main build thread, I'll give you the short story here. The first mobo ZipZoomFly.com sent me had been opened, it was deemed to be a returned/refurbished board not a truely new board, so I RMA'd it. The 2nd was the same story. I am RMA'ing it also. Now, given that a new revision of my board is expected to hit the shelfs at any time now, I have decided to WAIT until I can buy the newly revised version. I hope it won't be long, but I guess I am in for the duration. I figure getting two such boards is like a sign that I am suppose to build using the new board.

So, now you know why I had time to take these pictures and get them posted.

I (my Dad actually) made some homemade soft washers that I used to mount the PSU, the combo DVD/CDRW drive, and the floppy drive. I'll take a picture of those too.

My Dad (age 81) does the shop jobs for me. He did the soldering, did the cutting for the fans using tin snips made for cutting in a circle. Made the soft washers by slicing a rubber tube. Made the "quiet feet" using a commercial button cover cutter and some thick dense yet squishy rubber.

Lilla

Nice work Lilla.

Your PSU duct is exactly what I suggested; those barrier seem like nice touches. I've done it much more crudely and still have it work like a charm. The fan at the back of the PSU is far enough away that it doesn't take much sound absorption to get rid of whatever noise it makes (with a slow quiet fan) by the time it reaches the front bezel opening.

A couple of comments for when you finalize the setup (with a mobo...
)

1. Don't forget to copy Ralf's cable-gami with the data cables
2. Stuff unneeded voltage output cables from the PSU in the space above or beside it (on the right side of case). It's a tight fit, so friction alone will keep them there.
3. Unless you have compelling reason, trying getting rid of your front fan. Experiment with this -- your HDD temps may be already low enough. On the other hand, if removing the front fan doesn't reduce the noise, then you might as well keep it on. But do remove the fan guard - especially in that locations, totally unnecessary & it does reduce the airflow.
4. Remove the guard from the back exhaust fan. My cat has batted at it once but it probably spins too slow to hurt anyone & removing it WILL improve airflow.

MikeC, I'm glad to hear that I did OK. I really appreciate you added suggestions. I'll put them to work to be sure. I like finished look that the wire finger grills give, but if it would work better without them, then they are coming off. Updated photos will follow.

Yes, those cables, there is a mass of them coming from the power supply, I'll do my best to tuck them away in the way you explain.

And the ribbon cables are so wide that clearly they will need to be done right or they will block the airflow. I will definitely try to mimick Ralf's cablegami as best I can. Maybe I will practice folding the cables now while I am waiting on the motherboard, so I will have some techniques.

Lilla

Thanks for the pictures, Lilla. It's very interesting to see your work.



As a quick experiment tonight, I tried approach #2 in a 2nd PC (Celeron 900, HS:92mm L1A@5V, Exhaust:92mm L1A@5V), in which the NX-3000 PSU fan is the loudest noise in the system. An air duct from the front of the case is made from 3/16" foam board. I cut two rectangular barriers from foam board, the exact height of the duct, and slightly wider, so I could fold back the ends to hold each barrier upright in place, just with a friction fit.

Through the 1st barrier, I pressed 2 x 3/4" soft plastic tubes close to the outside edges of the case. I pushed this barrier into the duct - about 5" back from the front of the PC. Through the 2nd barrier, I pushed 2 x 3/4" tubes, roughly centred in the middle of the case. Then, I pushed this barrier just inside the mouth of the duct. There is no direct path for noise from PSU to front of case. The muffler tubes are offset between barriers.

I'm surprised to say that I do notice a difference. It's subtle, but the fan noise is gentler now. What I can still hear is noise from the back of the PC, reflected by the desk wall.

Paul, that's great. Glad to hear that the noise barrier helps.

I just uploaded some update pictures of my Evercase E4252 case preparation with PSU channel

MikeC, I removed the wire finger grilles, front and rear, and I took new pictures. I'm thinking that I might need the front fan only in the summer. If so, then I can unplug it in the others seasons and enjoy whatever extra quiet that brings. My computer room is upstairs and it can get plenty hot in the summer, so I feel good about having a little cooling in reserve.

I added a picture of the hard drive cage with rubber grommets. I even partial removed one grommet so you can see how the rubber grommets get installed.

I added a picture of the left side panel with the air holes that I covered over, and the side fan that I removed.

I added a picture of the homemade soft washers that my Dad made. This is a fun picture, it is the last one in the set (at this point anyway).

Lilla

Lilla - Can you elucidate about this statement?:

Does the rubber grommet mounting of drives etc make much difference?
If I understand correctly they have very little space between drive and drivecage. Does this really stop vibrations for beeing transfered to the drive cage?
My initial guess is that they make very little difference.


Now to the question of how to construct a PSU channel.
I might build my own some day when I have some time to spare.
Wouldn't it be more efficient if the barriers where tilted in the airflow path?
The result would be less restriction on airflow but still stop noise as efficient as straight barriers (or possibly more efficient). The drawback would be that barriers becomes slightly harder to mount securely.
Any thoughts on this?
Here is a picture of what I am thinking about:

Paul, for the remaining noise, three possibilites come to mind:
1) replace fan in PSU with quieter. This will void the warranty so for me at least, this would be a last resort.
2) add a PSU muffler, earlier in this thread I posted a link to a commercial one that could be easily made at home
3) add sound dampening/absorbing layers to the wall behind the PSU, so that the sound that comes out of the back of the PSU is handled.

A variation of muffler design presented at the link I gave in an ealier post in this thread, is to change the muffer design so that the air exausts out the bottom of the muffler rather than the back.

I have no personal experience with these methods.

You said you are using "foam board" is this the melamine foam board from McMaster's with the fiberglass coating on the outsides that you are using?

---


Ralf, it was posted by SometimesWarrier on Thu Oct 23, 2003 8:48 pm here

If the statement is not true, then please advise and I will remove that statement from my build picture site.

Lilla

1) Actually, I did this earlier. I've tried an 80mm M1A, then an 80mm L1A. I went back to the M1A (less clicking at the extra-low voltage that the fan control seems to put out; M1A is slightly quieter than the original MGA0812HS-A - but the MGA started up immediately at low voltage.
2) I've been thinking along this line, too. I think this is the next area I'll explore.
3) Clever suggestion. I hadn't thought of soundproofing underneath the desk.



Ha Ha. Nothing so sophisticated. Imagine "school project" poster board, but slightly thicker. Smooth paper on outside - Pressed paper and foam inside. Here's the description from www.staples.com:
20" x 30" foam board-perfect for school projects, signs, crafts, presentations, models and more. Lightweight and rigid with super smooth surface for mounting or painting. Easy to cut and shape. 3/16" thick.

Paul

Paul, I thought you might be interested in this article here

The author makes a PSU muffler that points down instead of straight back like the muffledcomputing.com design. The author says:



Lilla

Interesting article. You have a good eye, to catch the PSU exhaust foam channel reference buried in the Power-Snooze discussion.

In the Christmas Dell catalog that came in the mail it says something interesting about the current XPS system:

..., and a 460-watt power supply located in a separate compartment to minimize heat transfer to critical components. ...

Hummm, I wonder what their implementation looks like? Anyone know?

Lilla

Lilla -- it's been discussed. Try a search on the forums. Uses two 40 or 60mm fans with the PSU at the bottom of the case in a separated compartment.

MikeC, thanks, I found the thread, which included a link to a picture that shows the PSU placement in the chassis.



For anyone else who is interested, the thread where Dell's PSU compartment is discussed is here

And a picture of Dell's PSU compartment is here

Lilla

Here's an idea:

there are plenty of cases available that have a top blowhole. Take the fan out, leave the grill. used some thin cardboard or plastic to make a duct from the back of the psu to the "vent" (top blowhole) on the top of your machine.