Korg Forums

Davidb wrote:

keykent wrote:
I have a Kronos and I did this. The rat shack meter will only measure down to 50 dB SPL.
... I have an Oasys in another room where I often recorded vocals...

Hi Keykent,

Did you used the rat shack meter with the OASYS as well?
Are the measures close to those you had in the Kronos?

Just curious.

I have now. With the Goldline, I measured the O at 40 dB A weighted, which is the limit of the device. I then looked at C Weighting (which is much more sensitive to low frequencies) and got about 43 for the O and about 50 for the Kronos). Now the O and the Kronos are in different rooms, with the O in a quieter room; but the readings match my subjective impression that the Kronos is slightly louder than the O, mostly in the low frequency region. Remember that A weighting is a better match to the ear at these low levels, so is a better gauge, but unfortunately, the actual A weighted noise of the O is below the instruments capabilities.

The tough part about these plastic cooling fans is that there is always a variance in quality--so some fans are going to be noisier than others.

The Kronos uses a 60mm x 25mm 14.1cfm fan (the X-Fire RDM6025S). It's not the quietest fan - rated 22dB. Also, the fan is screwed directly to the SSD mount. This means if the fan is not balanced, the vibrations will resonate through the machine (thus the lower frequencies someone mentioned previously).

If you are a tinkerer, you could try replacing the fan with something quieter. I saw a couple fans here:

http://www.frozencpu.com/cat/l3/g33/c16 ... Page1.html

You could also try to use rubber mounts instead of screwing the fan directly to the SSD mount.

If you are a tinkerer, you could try replacing the fan with something quieter. I saw a couple fans here:

http://www.frozencpu.com/cat/l3/g33/c16 ... Page1.html

You could also try to use rubber mounts instead of screwing the fan directly to the SSD mount.

All of which would void your warranty. I wouldn't recommend doing this for at least 2 years after purchase. Just sayin......

I appreciate the scientific experiments in objective instrument sound level measurements. Yet, I can probably relate better to subjective impressions like "quieter than a fly buzzing in front of you at about four feet away" or "noiser than the airflow passing through a central air conditioning vent." Can any of you come up with creative or poetic descriptions of the fan sound in adjectives or simili based on what you're actually experiencing in a totally quiet room (I know there is no such thing, but let's say, not a store environment)? I'm trying to put it in perspective when I've only heard it in a store under the condition where I had to put my ear about 6 inches away to hear it.

My room is very quiet and I consider my 7200 RPM OWC hard drive to be a bit noisy (always relieved when it is off - ahhhhhhh.) My Macbook Pro is pretty quiet most of the time.

Mine fan is also very loud in the low frequency range, has a loud whirring, similar to but not as loud as a small beer refrigerator, similar to a PC tower (or 2!). It is WAY louder than my 7200 hard drive. Of course it is inaudible when playing the instrument. When my replacement comes in I will be very grateful if it is quieter. If not, I will have to suffer through it until a new model comes out and then this will be gone. It's just too loud and annoying to have in my space for ten hours a day. Would need to shut it off a number of times per day. I'm sure that it's just loose or something because my package was mishandled and abused.

I received my K73 yesterday. Will probably be going back soon due to a non-working touch screen (touches do nothing), and half of the faders don't work.

Anyway, the fan noise is different than the OASYS. OASYS has more high frequency hiss, Kronos has more low frequency hum. I'll try to record and measure tonight, and then again on the replacement unit.

Here is the parts page for the fan: RDM6025S.

http://www.qwikflow.com/DC_Fans/dc6025.pdf

Supposed to be rated at 22 dBA (under standard fan noise measuring conditions).

Personally, I'm disappointed in the volume of the noise. It's not terrible, but it's not great, either.

If my replacement unit is just as loud, I may look into rubber isolator mounts for the fan (http://4.bp.blogspot.com/-cOBf03IyqIQ/T ... G_3687.jpg)

Mark

The specs of the fan (link in previous post) with an alternative is:

___________Factory Unit___Alternative?
___________RDM6025S____Acoustifan AFDP-6025B
Size (mm) __60x60x25_____60x60x25
VDC_______12v__________12v
Current_____0.10 amps____?
Power______? watts_______0.96
RPM________3000________2700
CFM________14.10________13.7
Noise (dBA)__22.71________16.9

The Acoustifan is rated noticeably quieter and delivers 97% of the airflow. Those familiar with manufacturer will recognize that is within design tolerances. It is more expensive (~$22), but a small price compared to the Kronos. And it includes rubber mounts which should help with the low frequency noise. Seems like a good replacement fan for those who care.

http://www.quietpc.com/us-en-usd/produc ... afdp-6025b

Other possibilities (with more airflow):
http://www.quietpc.com/us-en-usd/produc ... /fd-fan-60
http://www.frozencpu.com/products/5221/ ... d=vZedI6HU

Mark

I've made some measurements and a recording.

Measurements with CEM DT-805, range down to 30dB:

Listening position, then directly over the master slider, and then off for reference:
On slow, dBA: 36.1..... 38.0..... 33.8
On fast, dBA: 36.0..... 37.6..... 33.6

Here's a recording: http://music.doctorobvious.net/KronosFan.mp3

Recorded with a GT AM51 condenser mic through a Yamaha 01v, mic about 18" above the screen pointed toward the Kronos.

This recording has been concatenated, but the sequence is:

On
Keys pressed (medium pressure)
Turn unit off
Turn unit on
Start up loud fan (probably the same as "high speed" when hot)
Then quiet fan (probably same as a very cold room)
Then typical fan (for my 75 degree room)
Then beep for ready
More key presses (moderate pressure)

Listening to the sections where the fan starts and stops should help people differentiate the fan noise and the room/mic/amp noise.

Hopefully this recording will help give some people an idea what the unit sounds like. I'm confident that a quieter fan and rubber mounts would help if it bothers people. I'll probably try a quieter fan/mount someday.

Mark.

Thanks for giving detailed information about the fan noise, Mark; it is very useful.
The noise really is too loud and bothersome for me, it sounds like the fan in my Dell internet computer.
I don't understand why KORG did not put more effort in implementing a quieter fan. Such a great workstation, and then using a noisy fan...

Fortunately, the fan can be replaced with a model which makes less noise.
If you decide to change the internal fan I would appreciate it if you could give some feedback about the difference in noise.

maphill wrote:The specs of the fan (link in previous post) with an alternative is:

___________Factory Unit___Alternative?
___________RDM6025S____Acoustifan AFDP-6025B

http://www.quietpc.com/us-en-usd/produc ... afdp-6025b

UK source:

http://www.prowiz.co.uk/magento/acousti ... m-fan.html

Acoustifan AFDP-6025B - £13.73 plus £4 postage

When I get a replacement, I'll see if the noise is similar and then consider whether to put rubber isolators on the fan and/or change it out.

A rubber/silicon gasket or spacer may be sufficient. Based on the pictures I've seen online, it seems like the fan is partially blocked by the SSD (which it is cooling). I wonder if the low frequency sound is minor cavitation? If so, simply spacing it away from the mount with a sealed spacer would allow it to still cool but with possibly less low-frequency noise.

I'll know more in a week or so I suppose.

Mark

Jan1 wrote:The noise really is too loud and bothersome for me, it sounds like the fan in my Dell internet computer.

The fan noise doesn't bother me at all. It is significantly quieter than the sound of playing the keys. Also, I don't notice it at all if I am actually playing the Kronos (either with headphones or through monitors).

I agree. I don't hear the fan when I play the Kronos, even at low volume. That's the bottom line.

However, the fan is audible in a quiet room and it is slightly annoying when I do other things in the room. The result is I have chosen to turn the Kronos off when I'm not using it and I'm in the room.

Minor issue with an otherwise wonderful instrument.

Keykent and Mark.
As stated thanks for suplying the community detailed information about the fan noise on both OASYS and Kronos.

Now we can say it´s not a peception but a fact, the Kornos fan can be noisy, and now we have data of how noisy the device can be.

And bases on those meditions you did, it seems as expected, the Kornos scores more and as a result is in general noisier tha OASYS, something I expected as Kornos does not have ventilation holes.

Mthomashow wrote:
However, the fan is audible in a quiet room and it is slightly annoying when I do other things in the room. The result is I have chosen to turn the Kronos off when I'm not using it and I'm in the room.

For what we read over here, it seems that some Kornos are noisier than others, though, something that happened with the OASYS too.
Mine is noisy, more than I would like.
Its even more evident in quiet environments.

For what it is worth,

the OASYS noise and the Kronos noise is different, and based on my memory, I found the OASYS noise more distracting.

It's important to remember that the Kronos uses less power and therefore has less heat to dissipate. It's my believe that if the low frequency issues with the Kronos fan can be dealt with (through isolation mounts, etc.) that it will be less distracting than the OASYS fan to almost all people.

Mark.