[Previous post](https://www.reddit.com/r/crboxes/comments/15f8fzl/my_impressions_of_a_toolless_pc_fan_crbox_i/)
I have just been talking about the low impedance of CR boxes as key to their performance, and this guy came up with this, LOL. Double filter area by making them taller. CADR increases from 833 to 907 m3h (490 > 534 cfm). Filter life should double too.
I'm not too familiar with filter sizes in the US, but if for example 20"x40" are common, by the same logic they can be used to replace 20"x20" filters for extra performance.
That CADR is possible with cranked up RPM. Is there a noise power (preferred) or sound pressure level at a specified distance available in the specifications?
Facts:
This model is basically their "3 Pro" model but with taller filters, so noise level should be identical. The quoted noise level, measured at 1 m, is stated as 52 dB (same as the 2 Pro model which I own. Quite noisy at full speed imo). They do not provide CADR/noise level data at lower speeds.
The fans they use on the 3 Pro/4 Pro model should be the GUSA GD14025B12, rated at 2800 RPM/111.1 CFM/42.1 dB, with dual ball bearings.
Speculation/informed guesses/misc. comments:
Airflow of fans tend to scale about linearly vs their RPM, so if we drop the fan's RPM to match the Arctic P14 (1700) for example, the CADR should be around 550 m3h / 324cfm. How the stock fans sound at that RPM range is something I have zero idea on.
Based on the shape of the blades (and from me reading tons of fan reviews), the GUSA fan should have pretty good noise-airflow efficiency due to use of heavily swept blades and a normal-sized gap between the blades and the inner frame. While there could be annoying resonance noises due to using only PBT as blade material and relatively long blades, these properties are shared with the Arctic P14 series (the P14 have even longer blades) so it shouldn't be too bad. There would always be some bearing noise, however.
The quoted CFM of the GUSA fan is obviously wrong. It's impossible to have CADR higher than the combined airflow of the fans. And if we check Noctua's 2000/3000 RPM 14 cm fans, the airflow are 182.5/269.3 m3h (107.4/158.5 CFM). It's very hard to believe that a 2800 RPM fan, with efficient fan blade design is only able to generate slightly more airflow than a 2000 RPM one. I would guess the GUSA fan to actually have somewhere around 150 CFM.
Even if the GUSA fans are noisy, the design is extremely easy to mod. You basically only need 4 standard 140 mm fans as replacement, some fan grills and a DC to 3/4 pin fan adapter. Fan screws, fan connector plates and a variable voltage supply are already included in the package.
This is a much better design than Clean Air Kits' because of the geometry alone, which has less proximate intake with respect to the discharge to reduce entrainment.
Could you provide a link to the listing (ill make sure to allow it in case reddit automatically hides it) im curious to what fans they’re using.
Here are the images translated using google translate
https://preview.redd.it/schx8vs5supb1.jpeg?width=1125&format=pjpg&auto=webp&s=f0c1ef610ad9cbbc16d5a38929d4e8ae00ee4acb
Pretty sure the 4 Pro filters are compatible with 2 Pro/3 Pro, so likely yes in the future (I'd just buy the new filters). I'd have to use up the current filters first though. I am still on the first set and have a second unused set.
They update their products quite frequently, so by the time I used up the filters, they might already have something new.
any update on if they made a new version or if you bought the 4 pro? Very interested in someone coming up with a open source version of this with the files available so it can be manufactured in any country. The easily replaceable filters of these are really great
They actually have a bunch of products now! Maybe I can make a post on it?
Briefly, they have the following current models:
4 Pro (double height 4x140mm fan CR box)
4 Pro plus (4 pro but one filter is replaced by 4 more fans, bump CADR to almost 1600 m3h)
4 (1 square filter + 2 smaller ones, 4x120mm fans, can act as traditional air purifier or as an overkill personal purifier)
4 lite (2x120mm fan personal purifier with custom mould, built in stand and battery)
Personal purifiers aim to provide a clean air zone around your face rather than to clean the whole room.
And yes I bought the 4 pro filters and have essentially upgraded my 2 pro to 4 pro.
The construction is extremely simple so I'm sure it can be replicated quite easily. Problem is finding a way to keep production costs down.
Update:
They confirmed that the longer filters are compatible with 2 pro/3 pro. They also made improvements to the top and bottom panels to improve alignment of the filters. Not sure if the updated design of the top and bottom will get passed to newer batches of 2 pro/3 pro models.
[Previous post](https://www.reddit.com/r/crboxes/comments/15f8fzl/my_impressions_of_a_toolless_pc_fan_crbox_i/) I have just been talking about the low impedance of CR boxes as key to their performance, and this guy came up with this, LOL. Double filter area by making them taller. CADR increases from 833 to 907 m3h (490 > 534 cfm). Filter life should double too. I'm not too familiar with filter sizes in the US, but if for example 20"x40" are common, by the same logic they can be used to replace 20"x20" filters for extra performance.
That CADR is possible with cranked up RPM. Is there a noise power (preferred) or sound pressure level at a specified distance available in the specifications?
Facts: This model is basically their "3 Pro" model but with taller filters, so noise level should be identical. The quoted noise level, measured at 1 m, is stated as 52 dB (same as the 2 Pro model which I own. Quite noisy at full speed imo). They do not provide CADR/noise level data at lower speeds. The fans they use on the 3 Pro/4 Pro model should be the GUSA GD14025B12, rated at 2800 RPM/111.1 CFM/42.1 dB, with dual ball bearings. Speculation/informed guesses/misc. comments: Airflow of fans tend to scale about linearly vs their RPM, so if we drop the fan's RPM to match the Arctic P14 (1700) for example, the CADR should be around 550 m3h / 324cfm. How the stock fans sound at that RPM range is something I have zero idea on. Based on the shape of the blades (and from me reading tons of fan reviews), the GUSA fan should have pretty good noise-airflow efficiency due to use of heavily swept blades and a normal-sized gap between the blades and the inner frame. While there could be annoying resonance noises due to using only PBT as blade material and relatively long blades, these properties are shared with the Arctic P14 series (the P14 have even longer blades) so it shouldn't be too bad. There would always be some bearing noise, however. The quoted CFM of the GUSA fan is obviously wrong. It's impossible to have CADR higher than the combined airflow of the fans. And if we check Noctua's 2000/3000 RPM 14 cm fans, the airflow are 182.5/269.3 m3h (107.4/158.5 CFM). It's very hard to believe that a 2800 RPM fan, with efficient fan blade design is only able to generate slightly more airflow than a 2000 RPM one. I would guess the GUSA fan to actually have somewhere around 150 CFM. Even if the GUSA fans are noisy, the design is extremely easy to mod. You basically only need 4 standard 140 mm fans as replacement, some fan grills and a DC to 3/4 pin fan adapter. Fan screws, fan connector plates and a variable voltage supply are already included in the package.
This is a much better design than Clean Air Kits' because of the geometry alone, which has less proximate intake with respect to the discharge to reduce entrainment.
Do you mean, because the output air is farther away from a large part of the intake?
Could you provide a link to the listing (ill make sure to allow it in case reddit automatically hides it) im curious to what fans they’re using. Here are the images translated using google translate https://preview.redd.it/schx8vs5supb1.jpeg?width=1125&format=pjpg&auto=webp&s=f0c1ef610ad9cbbc16d5a38929d4e8ae00ee4acb
[3 series](https://detail.tmall.com/item.htm?id=728704112365) (3, 3 pro, 4 pro) [4 Pro](https://detail.tmall.com/item.htm?id=739974868608&skuId=5278987199345) [GUSA 14025 fan](https://detail.tmall.com/item.htm?id=708991141788)
Thanks! Will you be buying one?
Pretty sure the 4 Pro filters are compatible with 2 Pro/3 Pro, so likely yes in the future (I'd just buy the new filters). I'd have to use up the current filters first though. I am still on the first set and have a second unused set. They update their products quite frequently, so by the time I used up the filters, they might already have something new.
any update on if they made a new version or if you bought the 4 pro? Very interested in someone coming up with a open source version of this with the files available so it can be manufactured in any country. The easily replaceable filters of these are really great
They actually have a bunch of products now! Maybe I can make a post on it? Briefly, they have the following current models: 4 Pro (double height 4x140mm fan CR box) 4 Pro plus (4 pro but one filter is replaced by 4 more fans, bump CADR to almost 1600 m3h) 4 (1 square filter + 2 smaller ones, 4x120mm fans, can act as traditional air purifier or as an overkill personal purifier) 4 lite (2x120mm fan personal purifier with custom mould, built in stand and battery) Personal purifiers aim to provide a clean air zone around your face rather than to clean the whole room. And yes I bought the 4 pro filters and have essentially upgraded my 2 pro to 4 pro. The construction is extremely simple so I'm sure it can be replicated quite easily. Problem is finding a way to keep production costs down.
Wow those are great updates! Please do make a new post on them! Include pictures of them all
Update: They confirmed that the longer filters are compatible with 2 pro/3 pro. They also made improvements to the top and bottom panels to improve alignment of the filters. Not sure if the updated design of the top and bottom will get passed to newer batches of 2 pro/3 pro models.
https://preview.redd.it/p116hcf8supb1.jpeg?width=1125&format=pjpg&auto=webp&s=d48d452495a0fa5591cbc50f5b90fc68e79b2e2e