What is the Better Ratio to CFM/Sound

[xDiiThy]

I'm pretty sure the difference of dba will not be perceptible to the human ear but would like to know everyone else's opinion for my fractal design r2 case fans, should I go with 12v to 9v or 12v to 7v voltage reduction. Which way would be better performance without making my pc any louder, I read that a 3dba increase is not perceptible to the human ear, is that right?

Here are the stats for each and would like to know which is better to go for the 7v adapter or the 9v voltage reduction adapter.

10.725 dba for 14.625 cfm 9Volt
Approx 8 dba for Approx 10 cfm 7 volt

At the current 12 volts they push 19.5 cfm with 14.3 dba

Thank You,

 

[Karadjgne]

You can hear a 3db difference. If you take a single speaker at a specific volume setting and amperage, listen to it, then add a second speaker at the same settings, it only adds @3db, yet makes an audible difference, appearing louder. This is why most center channel speakers have dual speaker setups, to maintain voice clarity and loudness over the surrounding speakers.

Fans are no different. Considering that @30db is very quiet conversation, @20db a quiet whisper, anything less than @20db is almost inaudible. Running your case fans at 14db is so quiet that you'd have to be sitting right on top of them to notice the difference over 10db. At that volume, airflow volume is much more important than audio volume. I'd only add the 9v adapters if the noise bothers you, but it may have consequences on your case/cpu/gpu temps, albeit minor.

 

[xDiiThy]

You can hear a 3db difference. If you take a single speaker at a specific volume setting and amperage, listen to it, then add a second speaker at the same settings, it only adds @3db, yet makes an audible difference, appearing louder. This is why most center channel speakers have dual speaker setups, to maintain voice clarity and loudness over the surrounding speakers.

Fans are no different. Considering that @30db is very quiet conversation, @20db a quiet whisper, anything less than @20db is almost inaudible. Running your case fans at 14db is so quiet that you'd have to be sitting right on top of them to notice the difference over 10db. At that volume, airflow volume is much more important than audio volume. I'd only add the 9v adapters if the noise bothers you, but it may have consequences on your case/cpu/gpu temps, albeit minor.

Well I have two of them running and they are making the largest noise in my system and they are actually pretty loud somehow running at 14dba I think I might get the 9V adapter anyone else?

 

[Karadjgne]

Hmm, I have a define R5 window and both stock GP14 140mm fans mounted in intake and even at 60% they are both so quiet I barely hear them. They are actually quieter than the nzxt fans on my kraken x61 at 25%.

My r5 also has a 3 position fan controller built in, as well as whatever capability my mobo has for fan control. Have you explored that option too, since the r2 also has a built-in controller, basically working 12v-9v-7v for you.

 

[xDiiThy]

Hmm, I have a define R5 window and both stock GP14 140mm fans mounted in intake and even at 60% they are both so quiet I barely hear them. They are actually quieter than the nzxt fans on my kraken x61 at 25%.

My r5 also has a 3 position fan controller built in, as well as whatever capability my mobo has for fan control. Have you explored that option too, since the r2 also has a built-in controller, basically working 12v-9v-7v for you.

I have a core v1 case but have fractel design r2 silent fans 80mm, not the case lol

 

[xDiiThy]

Hmm, I have a define R5 window and both stock GP14 140mm fans mounted in intake and even at 60% they are both so quiet I barely hear them. They are actually quieter than the nzxt fans on my kraken x61 at 25%.

My r5 also has a 3 position fan controller built in, as well as whatever capability my mobo has for fan control. Have you explored that option too, since the r2 also has a built-in controller, basically working 12v-9v-7v for you.

I have the fractel design R2 silent series 80mm case fans not the case, I am running a Core V1 with two 80mm fans at the back it is an ITX Rig. I am using the rubber screws by the way.

 

[Karadjgne]

Ahhh. Oh ok. Well for you, airflow is actually more important than for most. With the relative compactness of that case, and the squeeze to get components to fit, you'll end up with more than your fair share of hotspots, areas with little to no airflow at all.

That said, I don't know of any 80 mm truly 'silent' fans. Quiet, yes, silent, no. Reason being is those fans have so little in the way of blade area, that in order to get any cfm worth mentioning, you have to turn up the rpm. Delta makes a seriously impressive 80mm fan, but at 4-6000 rpm and @60+ db(A), you really don't want to use it any other place than a server rack in a sound deadened room. Your fractal fans are actually very good for stock fans, but at 80mm they'll be a little louder than what most consider normal. But thats only because of their experience, usually running 120 or 140mm fans. Unless I'm pushing cpu temps, my dual 140mm intakes stay at around 4-500 rpm, so are totally inaudible.

With as little cfm those 80's are moving, I'd not take them below the 9v adapter. At 7v you could blow into the case and move more air.

Your best option would be replace those fans for comparable noise but greater cfm, giving you the ability to lower rpm, lowering noise but still having reasonable cfm.

https://pcpartpicker.com/part/noctua-case-fan-nfa8pwm
https://pcpartpicker.com/part/be-quiet-case-fan-bl028
https://pcpartpicker.com/part/silenx-case-fan-efx0815r

 

[xDiiThy]

Ahhh. Oh ok. Well for you, airflow is actually more important than for most. With the relative compactness of that case, and the squeeze to get components to fit, you'll end up with more than your fair share of hotspots, areas with little to no airflow at all.

That said, I don't know of any 80 mm truly 'silent' fans. Quiet, yes, silent, no. Reason being is those fans have so little in the way of blade area, that in order to get any cfm worth mentioning, you have to turn up the rpm. Delta makes a seriously impressive 80mm fan, but at 4-6000 rpm and @60+ db(A), you really don't want to use it any other place than a server rack in a sound deadened room. Your fractal fans are actually very good for stock fans, but at 80mm they'll be a little louder than what most consider normal. But thats only because of their experience, usually running 120 or 140mm fans. Unless I'm pushing cpu temps, my dual 140mm intakes stay at around 4-500 rpm, so are totally inaudible.

With as little cfm those 80's are moving, I'd not take them below the 9v adapter. At 7v you could blow into the case and move more air.

Your best option would be replace those fans for comparable noise but greater cfm, giving you the ability to lower rpm, lowering noise but still having reasonable cfm.

https://pcpartpicker.com/part/noctua-case-fan-nfa8pwm
https://pcpartpicker.com/part/be-quiet-case-fan-bl028
https://pcpartpicker.com/part/silenx-case-fan-efx0815r

So lowest is 9V what did you say would happen if I went for 7V?

 

[Karadjgne]

At 7v, you're estimating @10cfm. That honestly pretty low. That's 10 cubic feet of air in 1 minute. That's roughly equal to the amount of air in a birthday balloon. I have faith that you could probably blow up a balloon in less than 60 seconds. You have a cpu cooler and a gpu, both of which have their own respective fans, trying to cool heatsinks. If you don't give them air, they'll get it from somewhere, which is air that's recycled. Warm air pushed past a heatsink doesn't absorb as much heat energy as cooler air, so your components run hotter, which means hotter air recycled, its a very vicious cycle of repetition and not good for pc health in general.

Those fans I linked will all push @30cfm at @15db, so even at 9v, will still be moving @20cfm at @10db. That's @ double the airflow for @ the same db as your current fans.

 

[xDiiThy]

Ahhh. Oh ok. Well for you, airflow is actually more important than for most. With the relative compactness of that case, and the squeeze to get components to fit, you'll end up with more than your fair share of hotspots, areas with little to no airflow at all.

That said, I don't know of any 80 mm truly 'silent' fans. Quiet, yes, silent, no. Reason being is those fans have so little in the way of blade area, that in order to get any cfm worth mentioning, you have to turn up the rpm. Delta makes a seriously impressive 80mm fan, but at 4-6000 rpm and @60+ db(A), you really don't want to use it any other place than a server rack in a sound deadened room. Your fractal fans are actually very good for stock fans, but at 80mm they'll be a little louder than what most consider normal. But thats only because of their experience, usually running 120 or 140mm fans. Unless I'm pushing cpu temps, my dual 140mm intakes stay at around 4-500 rpm, so are totally inaudible.

With as little cfm those 80's are moving, I'd not take them below the 9v adapter. At 7v you could blow into the case and move more air.

Your best option would be replace those fans for comparable noise but greater cfm, giving you the ability to lower rpm, lowering noise but still having reasonable cfm.

https://pcpartpicker.com/part/noctua-case-fan-nfa8pwm
https://pcpartpicker.com/part/be-quiet-case-fan-bl028
https://pcpartpicker.com/part/silenx-case-fan-efx0815r

Yeah appreciate the links but all of them except for the 35 dollar, including shipping, 80mm noctua are not availble in Australia. That is why the Fractel Design were basically the best before going Noctua Redux which was 25 bucks with shipping. So about the voltage? 7 or 9?

 

[Karadjgne]

9.
Or
https://au.pcpartpicker.com/part/evercool-case-fan-fanaled8025b2
https://au.pcpartpicker.com/part/silenx-case-fan-efx0815r

 

[xDiiThy]

9.
Or
https://au.pcpartpicker.com/part/evercool-case-fan-fanaled8025b2
https://au.pcpartpicker.com/part/silenx-case-fan-efx0815r

They weren't available in Australia to but its fine, i'll get 9V adapters.