Question Does a bigger case actually run quieter if you’re using the same number of fans?

[QuestionAsker]

For my silent-focused, air-cooled music production PC I'm building:

I’m debating between two cases — the Fractal Define 7 and the Define 7 XL — and I keep seeing claims that the XL is quieter. But here’s where I’m confused…

If I’m using 140mm fans (which both cases support), the total number of fans I can install is the same in both. So wouldn’t the smaller Define 7 actually have better airflow (higher air pressure per volume), and therefore potentially run cooler and quieter at the same fan speeds?

Or is there something about the XL's larger internal space — more room for sound to dissipate, lower turbulence, etc. — that actually makes it quieter, even with the same fans?

Curious what others have experienced or measured here. Anyone done noise or thermal comparisons between the two with identical fan setups?

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SPECS / NOTE:

(air-cooled, trying to get it as quiet as possible at idle and light-usage. I don't mind higher noise / temps if I'm gaming or doing higher-intensive tasks... just need it as quiet as possible when recording with microphones and light usage)

 

[aigomorla]

well the bigger case would allow more noise suppression. Meaning more area for noise to get absorbed and not thrown.

As for the cooling, i would think larger case would perform worse then a smaller case if your moving the same amount of air, because a smaller case has a better turn around (meaning how many times all the air inside the case is being exhausted and fresh air in) vs a larger case, which can possibly trap some of the air without higher powered fans.

But i do not think it would be that noticeable between the two, unless you have more fans or more powerful ones.

 

[Paperdoc]

I agree the difference is likely very small, but I do NOT have direct experience. For the SAME number AND SIZE of fans, in a smaller case the airflow SPEED will be larger, so that MAY means slightly better rate of heat removal from hot surfaces. In a larger case the airflow path may may be more open and thus offer less airflow resistance, allowing slightly faster airflow speed BUT that airflow may be merely bypassing components to flow though open space. That would reduce the rate of heat removal from stationary warm surfaces. Bear in mind that the noise of the case vent fans is determined by their speed, and that speed is determined by a temperature sensor on the motherboard that should represent the temp of the hottest mobo components. So the more efficient the heat removal rate is, the lower those temperatures are and the slower the fans need to operate. HOWEVER, we really are talking about very small effects, and the real result for fan noise is minuscule, I believe.

People who use larger cases often then use larger fans which DO operate at lower speeds and thus are quieter. Those who claim larger cases are quieter may not report (or even recognize) that the FAN size is the main factor there, not the case size.

 

[BonzaiDuck]

So far the observations or responses seem sound, and who would have more experience in this than AigoMorla?

Personally, I'm beginning to feel crowded around my desk with machines in standard-size midtower cases. I think you might have more effective cooling if you could fit the same fans into a smaller case. You want higher pressure with restricted airflow over hot components, assuring that there aren't any "stale pockets" of space and air. You want air that has been warmed up to be exhausted immediately.

For this, some may remember I was a Hot-Dawg for custom "ducting" -- an overlap to my pseudonym handle. The result of the experiments is an affinity for the same formula. I use the same case (a Coolermaster model released around 2007) with the same techniques and similar fans. This was all designed around heatpipe cooling, and I'm soon going to see how it works with my very first usage of a selected 280mm AIO cooling solution.

 

[Heartbreaker]

I think style of case matters more than size. Though you will find more quiet focused big cases than small ones.

At low power levels internal components are going to be quiet. My GPU turns off it's fans, and the CPU fan goes whisper quiet.

So most of the noise near idle is going to be the case fans. Something like the Define 7 with solid front will baffle case fan noise more than common open front cases these days.

When I upgrade to a new PC, I bought a new cheap case with thin metal compared to my old Antec Solo battleship, the one big sound difference was how well the old Antec muffled HDD noise. Thick metal, baffled case, silicone grommets for HDDs.

I had to remove all HDDs from my new case as I could easily now hear them seeking. It's the only internal component that made significant noise during low power operation.

 

[BonzaiDuck]

I think style of case matters more than size. Though you will find more quiet focused big cases than small ones.

At low power levels internal components are going to be quiet. My GPU turns off it's fans, and the CPU fan goes whisper quiet.

So most of the noise near idle is going to be the case fans. Something like the Define 7 with solid front will baffle case fan noise more than common open front cases these days.

When I upgrade to a new PC, I bought a new cheap case with thin metal compared to my old Antec Solo battleship, the one big sound difference was how well the old Antec muffled HDD noise. Thick metal, baffled case, silicone grommets for HDDs.

I had to remove all HDDs from my new case as I could easily now hear them seeking. It's the only internal component that made significant noise during low power operation.

Many of the "Veterans" are still here in the forums -- they're still ALIVE if they were old back when. But during the first decade of the new Millennium, we were all involved in cooling innovation with our over-clocking obsessions. If we didn't do custom water-cooling or AIO water-cooling, then we studied heatpipe cooler comparison reviews, lapped our processors to the copper, found exotic thermal pastes, and designed custom ducts for airflow. And one of the refinements -- for the noise problem -- was to isolate the HDDs with rubber shock-absorbers where they are mounted to the case. It wasn't "hard", but fairly easy. It definitely made a difference. A big difference.

Thick or thin case-metal, there was a product you could buy by the square foot or yard, and I need to make an effort to remember the name of it. Skip that brand name! Here's a LINK to the same kind of product.

But this stuff can be mess to remove. As for the hard disks, like I said -- make shock absorbers for the disk mounts.

 

[mindless1]

The biggest source of turbulent noise (case itself - excluding a video card fan) is going to be the stamped out grates on the fan mounts - closest to the blades. Fractal's pics are terrible, can't tell if cutting those out will leave enough reinforcement or cause the fans to resonate the metal sheeting - I'd use rubber fan mounts.

At idle and light usage, the slowest that the 140mm fans will spin is likely enough, even shut off any front fans regardless of which case you use - use the case you like more. That is unless you have a semi or fully passively cooled PSU that shuts it's fan off at low load, then only having rear exhaust fan(s) will pull the PSU heat into the system.

Otherwise the particular PSU, fans, and your ability to control them are what's going to matter. This assumes a heatpipe CPU 'sink that also has a big, low RPM quiet fan.

 

[QuestionAsker]

Thank you all for the recommendations

For this, some may remember I was a Hot-Dawg for custom "ducting" -- an overlap to my pseudonym handle. The result of the experiments is an affinity for the same formula. I use the same case (a Coolermaster model released around 2007) with the same techniques and similar fans. This was all designed around heatpipe cooling, and I'm soon going to see how it works with my very first usage of a selected 280mm AIO cooling solution.

I recently saw a video on youtube where a guy took air ducting and made a duct directly from a front-intake fan to the CPU air cooling fan. I haven't sat down to watch the whole video but from what I remember seeing, he said it helped the CPU temps lower a lot.

Have you tried something similar? Wondering how much it helps with thermals. Seems like a relatively easy mod too.

The biggest source of turbulent noise (case itself - excluding a video card fan) is going to be the stamped out grates on the fan mounts - closest to the blades. Fractal's pics are terrible, can't tell if cutting those out will leave enough reinforcement or cause the fans to resonate the metal sheeting - I'd use rubber fan mounts.

At idle and light usage, the slowest that the 140mm fans will spin is likely enough, even shut off any front fans regardless of which case you use - use the case you like more. That is unless you have a semi or fully passively cooled PSU that shuts it's fan off at low load, then only having rear exhaust fan(s) will pull the PSU heat into the system.

Otherwise the particular PSU, fans, and your ability to control them are what's going to matter. This assumes a heatpipe CPU 'sink that also has a big, low RPM quiet fan.

There's actually a mod for this for the Fractal Define 7 cases, it does help a lot with noise once RPM's start ramping up:

https://www.reddit.com/r/FractalDesign/comments/1kositm/fractal_design_define_7_with_fan_inlets

 

[Quintessa]

tl;dr
If silence is priority over raw airflow, the XL tends to sound smoother with identical fans. But if you keep fans ultra-low RPM (sub-600rpm on 140s), difference shrinks, the smaller Define 7 will be plenty quiet and cooler. Many sound-focused builders go XL + ultra-slow fans just to drop noise tone, but either case will work if you keep your cooling tuned.

 

[BonzaiDuck]

Thank you all for the recommendations



I recently saw a video on youtube where a guy took air ducting and made a duct directly from a front-intake fan to the CPU air cooling fan. I haven't sat down to watch the whole video but from what I remember seeing, he said it helped the CPU temps lower a lot.

Have you tried something similar? Wondering how much it helps with thermals. Seems like a relatively easy mod too.



There's actually a mod for this for the Fractal Define 7 cases, it does help a lot with noise once RPM's start ramping up:

https://www.reddit.com/r/FractalDesign/comments/1kositm/fractal_design_define_7_with_fan_inlets

For "appearances" with case-lighting, I used Lexan to build ducts, which is tedious for the cuts that must be made. Otherwise, foam art board -- black will do -- works great with a glue called "Hold-The-Foam". You can make precise cuts and build a good duct, but it doesn't contribute so much to "bling".

I DID try or otherwise adopt the strategy you describe. The trick is to force airflow through narrower apertures across the hottest components, avoid letting it mix with stale case air, and exhaust it directly. You can do these things to varying degrees limited by the tedium, and it's important to remember that installed ducts must be removeable with some degree of ease.

Something I could do with the Coolermaster Stacker 832's involved CM's own model of a 12" barrel fan mounted as intended next to the motherboard. I had a Lexan duct-plate covering the motherboard, and the fan deployed to suck air from the rear of the board and exhaust it at the front and out the right side of the case.

In any "case" -- a pun -- I have a patent strategy born of repetition and habit. We old Anandtech veterans may have got weary of the tin-bending and other exploits. Some folks built evaporative coolers, and others had their water-loops routed through a Rubbermaid bin filled with ice-cube bottles and water.

 

[Fallen Kell]

Really the main benefits of the Define 7 XL vs the Define 7 are the larger radiators that can be used with water cooling, additional hard drive space if you need more drives, and the +3 slot wide vertically oriented position for a graphics card support (if you get a PCIE extension cable) so that the GPU doesn't block additional slots on the motherboard (the Define 7 only has +2, which is extremely limited as most cards are now 2.5 slot or 3 slot wide).

I have the Define 7 XL. I love it. It is quiet if you put in quiet fans, and have either a large air cooled CPU heatsink (like a Noctua NH-D15 G2 or similar) or a quiet AIO.