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General Liquid/Water Cooling Discussion For discussion about Full Cooling System kits, or general cooling topics. Keep specific cooling items like pumps, radiators, etc... in their specific forums. |
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10-29-2004, 01:38 PM | #101 |
Cooling Savant
Join Date: Dec 2003
Location: France
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Pitch seems ok:
1046: D4 Headset mic (I think it was?) + 4" desktop speakers may not (indeed) be optimal combo for reproducing 50Hz hum |
10-29-2004, 01:46 PM | #102 | |
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10-29-2004, 01:49 PM | #103 |
Cooling Savant
Join Date: Apr 2002
Location: North of France
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Nice lolito, 50Hz harmonics are clear (~3000tr/min for France).
[mode fr ] C'est quoi ton soft? Goldwave gérait pas ca... J'ai bien envie d'updater le dossier avec ca. [/mode] Thx |
10-29-2004, 01:51 PM | #104 | |
Cooling Savant
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10-29-2004, 02:06 PM | #105 |
Cooling Savant
Join Date: Dec 2003
Location: France
Posts: 291
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Roscal, I used Adobe Audition (ex CoolEdit Pro)
no problemo si tu veux faire un copier/coller (même si jai fait ça un peu Ã* l'arrache, comme on dit ) |
10-29-2004, 02:18 PM | #106 |
Cooling Savant
Join Date: Apr 2002
Location: North of France
Posts: 198
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C'est bon j'ai trouvé un freeware qui fait les FFT , ca rend très bien -> http://audacity.sourceforge.net/windows.php
Regarde la 1048 le fondamental est a 100Hz par rapport au 50 de la 1046, pourtant elle tourne a la même vitesse d'après leur moteur (3000 tr/min), bizarre que la fréq soit exactement le double, je vais réfléchir Ã* ca. |
10-29-2004, 02:52 PM | #107 |
Cooling Savant
Join Date: Dec 2003
Location: France
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Bizarre...
1048: As Roscal says, no 50HZ fundamental for this one?! Also note the cutoff at 7k or so (same for the other pumps) this is due to the mic and/or codec, and will have an effect on the perceived noise - of the D4 in particular DDC: small spike at 58Hz, moves up to 62Hz when the pump speeds up. 3480->3720rpm? |
10-29-2004, 03:08 PM | #108 |
Cooling Savant
Join Date: Apr 2002
Location: North of France
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Yep, DDC spins from 3465 tr/min at full flow to ~3900tr/min at 0"head. Codec cut high frequencies I think because I must compress sound records for bandwitch.
The 1048 is perhap's a bad recording but strange because I didn't change anything, just a pump replacement. There's a little spike at 50Hz but very small in comparison of 100Hz. |
10-29-2004, 05:28 PM | #109 |
Cooling Savant
Join Date: Feb 2003
Location: USA - Boston area
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Sounds like the D4 could become nearly as quiet as the DDC, given the right electronics (i.e. done as a product update/improvement at Laing).
Is it possible that this more sophisticated electronics might not get along so well with over/under volting? Might be why they went with square wave on the D4. Probably just a cost of goods issue, though... Last edited by bobkoure; 10-29-2004 at 07:18 PM. Reason: typo |
10-30-2004, 08:54 AM | #110 |
Cooling Neophyte
Join Date: Sep 2004
Location: texas
Posts: 68
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Simple coil switching of the motor coils is definitely the simplest and cheapest solution. It reduces losses in the drive circuitry and it also gives you more power out of the motor compared to a sinusoidal drive. The cost is reduced motor efficiency, increased motor heating, and increased noise. It's certainly possible to design a sinusoidal drive that will undervolt well, but cost, efficiency, and drive circuit dissipation tradeoffs may weigh against it. A sinusoidal drive shouldn't add more than $1-$2 to cost of manufacture.
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10-31-2004, 04:50 PM | #111 |
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After thinking about things, I am now more curious about the actual physical cause of the 50Hz switching noise of the D4. It cannot be electronic in nature, since electrons don't make noise.
So, is it the electromagnets vibrating as they are turned on and off? Is it vibration of the shaft as it is subjected to changing torque when the electromagnets turn on/off? Is the amplitude of the noise caused by the required travel freedom of the D4 spherical rotor? Would a traditionally axle driven rotor be less noisy for a given drive electronics type because it might be less "sloppy" ? |
11-01-2004, 11:57 AM | #112 |
Cooling Neophyte
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When you switch the coils on it generates a sudden torque pulse on the motor. The rotor is given a sudden push, and the pump frame experiences the same torque pulse in the opposite direction. Sort of like hitting it with a hammer at 50HZ to make it go around . Something similar happens when the coils suddenly turn off.
You can modify the abruptness of the torque pulses by changing where in the rotation you turn the coils on and off. If you turn the coils on when the magnetic field is at it's strongest on the coils you will get the worst case, if you turn the coils on before the rotor rotates into the strongest part of the field the initial torque pulse is less. You can also reduce the abruptness of the torque pulse by turning the coils on and off slowly which is essentially what a sinusoidal drive does. You can also get noise from the metal laminations that are used to build the core of the electromagnets. As the magnetic field is turned on and off they are alternately pulled together and apart. This is not usually a dominate noise source. |
11-02-2004, 03:33 PM | #113 |
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Thank you ferdb. That was what I expected to be the answer, although you describe it much more clearly!
I guess the operative question is "Why is the Laing pump so noisy in comparison to other pumps?" Is it doing a trade-off of noise versus efficiency that other pumps don't? Or is it made with cheaper tolerances so that the vibration from torque on/off is less damped (i.e. accumulating the energy from torque accel over time to deliver a rapid impulse when the slop factor is reached)? The reason for asking is to see what the probability is for the pump mfg to produce a decent (still high head and low temperature) pump that is quieter if a bit more money is thrown into production costs or if we are experiencing a natural consequence of the required performance. You get what you pay for, but you can't pay to remove the laws of physics. |
11-03-2004, 11:18 PM | #114 |
Cooling Neophyte
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I'm sure most of the noise comes from the brushless dc motor and little from the pump. So if you make a quiet motor, you'll have a quiet pump. It's certainly doable, the question is is the market for such a pump big enough to bother with and will that market pay the price premium necessary for such a pump.
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11-04-2004, 03:27 AM | #115 | |
Cooling Savant
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(apologies if you already knew this!) |
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11-05-2004, 07:58 PM | #116 | |
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Thank you, though. |
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11-06-2004, 05:20 AM | #117 |
Cooling Neophyte
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Location: Nashville, TN
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All I want to know is where I can buy one.
EDIT: Ack. Current pump failed. Cooked a Radeon 9800Pro 256. I just ordered the MCP650 directly from Swiftech. :shrug: Last edited by SLI_Fallen; 11-07-2004 at 06:28 AM. |
11-14-2004, 09:32 PM | #118 |
Cooling Neophyte
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Location: Scarsdale, NY, The U S of A
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Sorry if this is mostly off topic, but does anyone know how MCP350 and MCP650 compare to CSP-750 purely on the grounds of acoustics?
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11-15-2004, 03:44 AM | #119 |
Cooling Savant
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Location: France
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MCP350 (DDC) is apparently "inaudible"
CSP-750 should also be inaudible, but I have heard of people claiming it gurgles. MCP650 (D4) is far from silent, but it's likely a new version will fix that. |
11-15-2004, 08:55 PM | #120 |
Cooling Neophyte
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I don't hear my CSP-750s gurgling. In a closed case sitting on a piece of foam I cannot hear them at all. If somebody is hearing gurgling I would guess they still have bubbles in their system.
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11-15-2004, 09:21 PM | #121 | |
Cooling Neophyte
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Quote:
It's hard to get manufacturers to increase costs and decrease efficiency for something as nebulous as quietness. Last edited by ferdb; 11-15-2004 at 09:30 PM. |
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11-16-2004, 12:45 AM | #122 |
Cooling Savant
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My CSP-750 (which I bought from Ed) is definitely not inaudible. I run it a little over 7V to get rid of a whining sound not unlike a hard drive's. No gurgling noises, but my flow must be little more than 2LPM at 7V. The lower pump speed costs me about 2C on the reported CPU temp. And you need a quiet system/environment for a CSP to be a noise problem.
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11-17-2004, 08:33 AM | #123 |
Cooling Neophyte
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Do you have your CSP750 sitting on foam?
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11-17-2004, 08:36 AM | #124 | |
Cooling Neophyte
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11-18-2004, 05:10 AM | #125 | |
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