Koolance PMP-500 Pump

Posted: December 13, 2012 in Pumps
Tags: , , , , ,

Noise – Subjective Tests

For a quick sound check, I’ve uploaded two videos, this first is using my iphone5 without any background noise.

And the second it with some 1200RPM fans running in the background.  This one I recorded with my Canon T2i and 18-55IS kit lens.

It is subjectively louder than the PMP-450.

Noise – Quantitative Tests

Did a side by side PMP-450 vs 500 comparison on a fixed restriction condition.  First I set up the 450 and turned it all the way up to setting 5 @12V, then I dialed in restriction such that it peaked right at 2.0GPM.  This represents a fairly low restriction loop.  Then I turned the pump all the way down to setting 1 and started recording with a sound level meter upwards in increments of 0.1GPM.  I removed the PMP-450 and installed the PMP-500 using that same restriction setting and ran test two the same way.  Both pumps were fully decoupled using the soft part of an Aquacomputers Shoggy sandwich which is a very soft silicone like sponge which does an excellent job at decoupling vibration.

The test were done in the evening when the house was pretty quiet with no fan noise to mask the pumps, so it is a bit extreme and will sound much louder than real world use where fan noise blends and hides most of the noise. I just needed to do this so I could more accurately compare the two pumps.

PMP-450 Test

PMP-500 Test

For a very good personal listening exercise, I would start and pause both videos above until you match up like flow rates.  Then go back and forth between each video for a more apples to apples audio comparison.  That’s always been my personal favorite way of doing it (screw the noise meter, let me listen!..:))  However, we like counting beans, so I’ve also done the work for you and pulled the information from the sound level meter to produce the following:


My previous pump noise king the Koolance PMP-450 retains it’s crown.  The PMP-500 trails by approximately 1-4dbA depending which is noticeably louder.  Both pumps did have harmonics spikes a bit throughout though, so it reinforces the need to experiment with speeds too.  Even fully decoupled, it’s very possible to lower noise levels by turning a pump “UP” if you can fall down in one of the dips.

Also if you refer back to my round 1 pump testing, some other pumps like the Swiftech MCP35X also trailed the PMP-450 by a couple of dbA.  The PMP-450 is exemplary at low noise pumping performance, so it’s a tough competitor to compare to.

The big kicker however is the peak noise level where the PMP-450 at full tilt was producing a very soft 38dbA, but the PMP-500 @12V was at 49dbA which is 11dbA higher.

Using the following chart for perceived noise level differences:

Perceptions of Increases in Decibel Level
Imperceptible Change 1dB
 Barely Perceptible Change 3dB
Clearly Noticeable Change 5dB
About Twice as Loud 10dB
About Four Times as Loud 20dB

It would say that the PMP-450 at like flow rates is barely to noticeably quieter than the PMP-500.   At full speed (different flow rates) however the PMP-500 is perceived about twice as loud as a PMP-450.  Weather or not this is important to the user depends highly on placement in the system and background noise.  The more buried the pump is in a case, the more obstruction and muffling you gain by the case itself.  In addition the background noise levels and type of noise makes a big difference in how acceptable the noise is.  Ultimately the only complete test in noise is trying it yourself, but I hope this at least gives you some indication.

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  1. Kevin Hua says:

    Finally, a pump that has dethroned the ddc series in all aspects! Nice testing Martin, I’ll be sure to pick up this pump! Maybe a custom pcb can lower power draw/noise… It’s using the old style transistors for power.

    • Martinm210 says:

      Yeah, if noise can be reduced via PCB and motor controller upgrades to say less than 40dbA max and a comfortable like tone that blends/hides well in your typical fan noise, that would be sweet. Add PWM to that and you would have one hard to beat little pump..:)

  2. nleksan says:

    So glad to have you back!!!!!!!!!!

    You are truly a pillar of the water cooling community, and if it weren’t for yourself and the few like you who have been so incredibly dedicated to scientifically analyzing and reviewing anything and everything water cooling, it’s quite likely that the hobby would still consist of a lot of non-modified aquarium pumps, semi-custom “water blocks”, and heater cores! I realize that you are a humble man, but take a moment to recognize the immense contribution you have made to “PC Water Cooling” as a whole, and if you’re ever nearby I’ll buy you a beer, hell, I’ll buy you a keg!

    • Martinm210 says:

      🙂 … Thanks!! and Cheers!!

      • Cole Markusen says:

        Not a problem. Might have to step up and buy one of Koolances controllers. The tone/pitch is almost unbearably annoying after long periods of time. Obviously the controller won’t get rid of it but lessen the severity a bit. Any idea what kind of components those controllers use? Would hate to have the same noise issue as the fan controller.

  3. Hi Martin,

    I lost my rubber washer (https://martinsliquidlab.files.wordpress.com/2012/12/koolancepmp500-16.jpg)

    I would like to know if my pump will get flooded or I can run the pump without.

    Thank you,

  4. Hi Martin, I just had a failure on my power supply just 20 minutes after starting my system with a PMP-500, an ATI 7870 and a FX-8350 oced to 4,6ghz, my power supply was a corsair GS700 with a single 12v rail of 56A, can you tell me what power supply should I buy to move all this without problem? Thank you!

    • Martinm210 says:

      I have had good luck with my TX650 and a single 570gtx card and hot hexacore, but I’m not up to speed on what the latest cards are drawing. I would plug it all into one of the online power calculators and base it on that. I would also check reviews on newegg on any model you are looking at and watch for how many bad reviews there are.