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PART 3[ index ]ABOUT THIS PART :Contniuing of from where I left off some months ago. What's changed ?
Modifications to cabinet : HD relocation and damping (independently suspended box). See the noisebox project. Some sound recordings from the different scenarios. Note ! Systems settings used throughout this part are : CPU=233Mhz, bus= 66 Mhz and Vcore=3.2 Volts.
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FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | ON | Disabled | CPUIdle | Open |
Comment : Disabled CPU Fan to see how stable system was without it. Cabitnett
cover was removed to improve the airflow, and reduce the load on PSU cooling fan which
also needs to cool the rest of the cabinett.
Sound recording : take-1 (2 sec. wave loop) / full take mp3 at 128kbps (mono)
take-1 : Scenario : case cover open, PSU fan disabled, HD spinning.
Description | Filename | Type | Size |
Recording of situation #1 | take-1-2s.wav | WAV | 176 440 |
" " |
take-1-2s.mp3 | MP3 | 33 436 |
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | OFF | Disabled | CPUIdle | Open |
take-2 : Scene : now with HD shut down. (might have to retake, not full 10 secs. but got the beginning clean.)
Description | Filename | Type | Size |
Recording of situation #2 (1.5 sec. take) |
take-2-1.5s.wav | WAV | 131 644 |
Full 8 seconds mp3 recording at 128kbps (mono) with HD booting up-again 2 secs. into recording. Gives an impression of relationship between levels. | take-2-8s.mp3 | MP3 | 124 133 |
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | ON | ON | CPUIdle | Open |
take-3 : Scene : now with CPU FAN, open chassis, HD spinning.
Description | Filename | Type | Size |
Recording of situaton #3 | take-3-2s.wav | WAV | 179 696 |
" " |
take-3.mp3 | MP3 | 173 871 |
2 second loop-recordings.
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | OFF | ON | CPUIdle | Open |
take-4 : Scene : as in (3) but With HD spunn down.
(Very noisy recording.)
Listen to it :
Description | Filename | Type | Size |
Recording Situation #4 (1 sec.) |
take-4-1s.wav | WAV | 88 468 |
Recording Situation #4 (5 sec.) |
take-4-5s.mp3 | MP3 | 81 502 |
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | ON | ON | CPUIdle | Closed |
****** Now putting the chassis cover back on *******
take-5 : Scene : System operates quietly. HD on , CPU FAN ON.
! Note on the recording, noises stemming from someone building stuff in the
neiboring room.
System is so quite that i can hear the transformer noise from the monitor. Long time
since.
Well actually, on opening the monitor and exsamining the source ... the noise was comming
from the high-voltage area of the printboard mountede on the back of the picture tube. Not
much I could do about it. Tried to dampen the protective metal grid, but no effect. This
was not the source of the noise. I'm uncertain as to what the cause of problem is - and as
how it can be eliminated. There was no noise comming from the monitor when I bought it and
it was new. But it came creeping in gradually with time, that is after a couple of weeks.
Well well. I don't want to risk my life exploring this problem any futher, the voltages
here are to high so I'll guess I'll just have to get a new monitor without noise. Where
ever they can be found !?
Listen : click on filename to hear the recordings.
Description | Filename | Type | Size |
Situation #5 recording | take-5.wav | WAV | 174 938 |
" " |
take-5.mp3 | MP3 | 16 224 |
Monitor Noise recording | take-5-1.wav | WAV | 176 542 |
" " |
take-5-1.mp3 | MP3 | 16 224 |
(Note : level deviation SW amplified by +35dB)
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | OFF | ON | CPUIdle | Closed |
take-6 : Try with HD spun down. (Great ... monitor
makes most of the annoying noise. )
Listen : take-6.wav (2 s)
Description | Filename | Type | Size |
Recording of situation #6 | take-6.wav | WAV | 179 562 |
" " |
take-6.mp3 | MP3 | 16 640 |
Note monitor have been on during all recordings sofar. And with the HD spun down, it is perceived as the dominant anoying sound.
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | ON | ON | Default | Closed |
take-7 : Disabling the CPU-idler ... se what
happens ... [ Amplified (SW) by only +20dB to get recording relative to natural room
sounds such as breathing etc. ]
System state : everything is on.
Result : Noise level increased instantly, as PSU FAN geared up. Listen to it. HERE.:
Recordings split ut in time periods over a total of 28 minutes. (Need to cut this down)
Listen : take-7.wav (several extracts at diffent time points)
1 second snapshot. loop to get the impression. .wav & .mp3 versions.
Description | Filename | Type | Size |
00:10 (mm:ss) | take-7-0-10.wav | WAV | 88 600 |
00:30 | take-7-0-30.wav | WAV | 91 198 |
01:00 | take-7.1-00.wav | WAV | 86 640 |
04:00 | take-7-4-00.wav | WAV | 91 196 |
08:00 | take-7-8-00.wav | WAV | 95 756 |
16:00 | take-7-16-00.wav | WAV | 95 754 |
24:00 | take-7-24-00.wav | WAV | 91 198 |
28:00 | take-7-28-00.wav | WAV | 91 196 |
Description | Filename | Type | Size |
00:10 (mm:ss) | take-7-0-10.mp3 | MP3 | 8 320 |
00:30 | take-7-0-30.mp3 | MP3 | 8 528 |
01:00 | take-7.1-00.mp3 | MP3 | 8 112 |
04:00 | take-7-4-00.mp3 | MP3 | 8 528 |
08:00 | take-7-8-00.mp3 | MP3 | 8 944 |
16:00 | take-7-16-00.mp3 | MP3 | 8 944 |
24:00 | take-7-24-00.mp3 | MP3 | 8 528 |
28:00 | take-7-28-00.mp3 | MP3 | 8 528 |
** Note this recording gives a relationship between the noise-level and natural sounds of movement in the room. Me entering the room slaming the door etc. | take-7-end-entering-room.mp3 | MP3 | 222 560 |
FACTORS > | CPU state | HD state | CPU Fan | SW running | Cabinett |
State > | Idle | ON | ON | CPUIdle | Closed |
Take-8 : Now enable CPU-idler software again and
observe ...
Result ... Instand drop in PSU FAN noise, slowly gearing down to silence in about 5
minutes.
Listen : ( 1 sec. snap-shots at different time locations. .wav .mp3 versions)
Description | Filename | Type | Size |
00:06 (mm:ss) | take-8-0-06.wav | WAV | 87 276 |
00:30 | take-8-0-30.wav | WAV | 180 740 |
01:00 | take-8-1-00.wav | WAV | 174 508 |
02:07 | take-8-2-07.wav | WAV | 174 508 |
05:00 | take-8-5-00.wav | WAV | 193 200 |
Description | Filename | Type | Size |
00:06 (mm:ss) | take-8-0-06.mp3 | MP3 | 8 320 |
00:30 | take-8-0-30.mp3 | MP3 | 14 965 |
01:00 | take-8-1-00.mp3 | MP3 | 14 600 |
02:07 | take-8-2-07.mp3 | MP3 | 14 600 |
05:00 | take-8-5-00.mp3 | MP3 | 16 060 |
REMAINING :
Do recording with exhaust pipe on : Several noise trap prototypes are beeing tested. So far with great success with respect to the HighPithced PSU noise, but not so well on PSU Fan noise.
Do recording when HD have been boxed, and relocaded. Results so far in standalone suspension (isolated from the rest of the cabinett chassis, have been great. What remains are the high pitched whining noise; which I hope the "box" will sort out. Seek and vibration noise have almost been eliminated.
OO - Sound recordings are not very informative. Noise levels are to low to be recorded
properly. Need to boost the levels. Do the meter reading as well. (at the end).
Adding of new style exhaust-pipe-muffler-stuff. (Not yet completed).
Noises still present : Monitor (findings see situation #5). PSU (High-pitched ones).
Relocation of HD : The encapuling of the drive to remove the HF noise from PSU (as well as Fan noise).
Cabinet modifications : Adding mass. Damping materials. Gluing. GREAT Success. Link to
similar project.
The cabinett damping method have allready prooved sucessfully in a preceeding AT cabinett.
- The CPU-Idle utility (v.5.6) (at www.cpuidle.de )
really saved the day. It is a must have ... and with the quick and dynamic response of the
new PSU, you can hear the fan speed change instantly with CPU load.
- The noise level has now become livable.
- The noise level now relates to the power consumption of the system. Which is good.
- The CPU FAN noise
level was reduced by adding rubberbands on both sides of the 4 screws that conected the
fan to the cooling element. The idea was to make somekind of FAN
"suspension". This didn't work very well. What did work however was bending the
ribs of the cooler, so that the screws fastened more tightly. (It is possible that the
rubberbands made the fit between fan and cooling element better, reducing
vibrations).
- The notorious High-Pitched noise have haunted me all along. Even this "High
Quality" PSU has this anoying quality. I've come to the conclusion that this must be
part of the SWITHCING PSU's nature.
At least I never heard that type of sound in the older AT PSU's . The possibility that it
is motherboard dependant still exist, but I don't think so. As mentioned else were it was
possible to reduse it by altering the power management something in the control pannel.
The sound dissapears when pressing the mousebutton as before....
Hmmm. It appears that pressing the mouse button, brings the system out of it's idle state.
And starts to consume more power. Wonder wonder ... ???
But the noise characteristics isn't that anoying on this one at least. (Comfort,
comfort ...)
Update on the issue [23.10.2000] : The HF noise from the PSU is dependant on the systems
power consumption. Problem increase as system power consumption decreases. Pressing the
mouse button removes the sound because system is then brough out of it's idle state, and
power consumption increases.
- Subjectivly ... Adding the case covering muted the sound characteristics
noticably. Particulary the high frequencies.
- Noise characteristics : It's easier to live with the low frequncy and soft sounds,
rather than the hard and high pitched ones.
- A dynamic noise level is also more digestable than a static one. It brings some kind of
life to the PC. You can hear that something is going on. When the fan boosts, you know
that it's working harder. ( A little positive thinking help a lot too).
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