I recently picked up a Thomann FIR DSP408 speaker management system as an upgrade from my Dayton Audio DSP408. It’s an absolute beast of a unit: 96kz sampling, XLR ins and outs and no noise at all whatsoever in the signal. However, because it’s designed for PA reinforcement in questionable conditions, presumably loaded into racks with amps and little ventilation, it has a fan that runs all of the time. That’s a bonus for pro audio, but for home use, it’s a deal breaker that defeats the low noise floor of the signal.
So, for home use with constant 70° ambient temperatures and adequate ventilation, is there any reason to have the fan running at all? Are there aftermarket fan controls that I could use to slow the fan to a whisper? The T. Racks otherwise works very well and is about a third the price of comparable units, I just can’t tolerate the fan noise.
I swapped the fan on my non FIR version to a silent one (noctua or something), and tore out the "grille" protecting the fan as it also made sound, turbulence or something. It's still audible, but not annoying anymore, similar to other noise around. I guess it could be left out altogether, try measure temperature inside the box somehow to be sure.
edit, Noctua it is. And dusty 😀 air coming out feels "cold" after the machine has been on about 8h now, so I suspect it could be tuned down considerably, or even left unconnected.
edit, Noctua it is. And dusty 😀 air coming out feels "cold" after the machine has been on about 8h now, so I suspect it could be tuned down considerably, or even left unconnected.
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I'd keep some level of fan in the unit. There is a huge difference between still air and even a slight breeze. I've got a PC P/S that has a variable speed fan and usually runs silently it spins so slow. But one day I smelled resistor burning and sure enough, the fan had stuck. Replaced it an smell was gone.
Hi tmuikku, thanks for the info - just have a few quick questions because I also can't tolerate the fan noise:
1. Do you know which Noctua fan you used?
2. Did you have to cut the casing of the dsp unit to make the swap?
3. Have you had any problems with dust in general? I don't think there's a filter on the inlet so I'm considering whether that could be useful to add.
Ideally I'd want continuously variable speed control for the fan or at least different levels I can set for home / PA usage so I'm working out options now.
Thanks
update: I removed the fan entirely and built a dedicated enclosure for the unit:
nearly 1 year on, I've had no problems with heat.
nearly 1 year on, I've had no problems with heat.
Hi SamElfring, the swap was easy as I remember, I might have needed to cut the cables because connector was different on the noctua fan. This is from my memory, not having the case open now.
I used the NF A4-20mm model, specifically was this PWM version which is likely why I had to cut the connector. I think the original fasteners and all worked just fine so overall quite easy swap. I bet you can use about any 40mm fan of theirs or from some other manufacturer.
https://noctua.at/en/products/fan/nf-a4x20-pwm
No other modifications needed as I remember. I cut the grille of because it was the loudest sound after swaping the fan, the air noise was quite audible. Casing pops open with few screws.
No problems with dust, this is home use and gets occasional cleaning. To be truthful I haven't paid any attention to the dust. I suspect it'll run few years fine until one should vacuum it to prevent fire, just like any gear with fan. Fan blows out, so the dust goes in otherside the box through the original grill that I left intact.
ps.
I have another unmodified unit, which is so loud that I threw a blanket on it while adjusting a system at home. I remember the unit got quite hot so it's a good idea to have more ventilation on it if the fan is removed completely, like gigantic's example shows.
I used the NF A4-20mm model, specifically was this PWM version which is likely why I had to cut the connector. I think the original fasteners and all worked just fine so overall quite easy swap. I bet you can use about any 40mm fan of theirs or from some other manufacturer.
https://noctua.at/en/products/fan/nf-a4x20-pwm
No other modifications needed as I remember. I cut the grille of because it was the loudest sound after swaping the fan, the air noise was quite audible. Casing pops open with few screws.
No problems with dust, this is home use and gets occasional cleaning. To be truthful I haven't paid any attention to the dust. I suspect it'll run few years fine until one should vacuum it to prevent fire, just like any gear with fan. Fan blows out, so the dust goes in otherside the box through the original grill that I left intact.
ps.
I have another unmodified unit, which is so loud that I threw a blanket on it while adjusting a system at home. I remember the unit got quite hot so it's a good idea to have more ventilation on it if the fan is removed completely, like gigantic's example shows.
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@tmuikku just completed the swap with the NF-A4x20 FLX model and it's much quieter so thanks for the advice. Swap was very easy with the adapter set that came with it.
Still making some audible noise but I suspect with music on and within the rack away from listening position it won't be anywhere near as noticeable as before.
Still making some audible noise but I suspect with music on and within the rack away from listening position it won't be anywhere near as noticeable as before.
Cool!
Yeah the "grill" makes turbulence and it's wind noise. Take sidecutters and cut the grill off so that the enclosure has big round hole, no obstruction ib front of the fan, and the noise goes down again.
You can test the difference first by opening the case, hold the fan on your hand and power on the device and hear it's almost silent. Keep it powered and put the fan to the position and hear how sound changes a lot louder.
Yeah the "grill" makes turbulence and it's wind noise. Take sidecutters and cut the grill off so that the enclosure has big round hole, no obstruction ib front of the fan, and the noise goes down again.
You can test the difference first by opening the case, hold the fan on your hand and power on the device and hear it's almost silent. Keep it powered and put the fan to the position and hear how sound changes a lot louder.
How is Papts better? In my opinion noise in home use is the most important spec, durability needs to be reasonable of course.
Specsheets, 414 is 24V fan, while noctua is 12V. PAPTS 412 seems to be 12V version.
https://www.ebmpapst.fi/fi/tuotteet/Laitetuulettimet/Aksiaalilaitetuulettimet.-DC/414
https://www.ebmpapst.fi/fi/tuotteet/Laitetuulettimet/Aksiaalilaitetuulettimet.-DC/412
https://noctua.at/en/nf-a4x20-flx/specification
Noctua has few db lower noise according to specsheets, which is likely due to difference with speed?
Specsheets, 414 is 24V fan, while noctua is 12V. PAPTS 412 seems to be 12V version.
https://www.ebmpapst.fi/fi/tuotteet/Laitetuulettimet/Aksiaalilaitetuulettimet.-DC/414
https://www.ebmpapst.fi/fi/tuotteet/Laitetuulettimet/Aksiaalilaitetuulettimet.-DC/412
https://noctua.at/en/nf-a4x20-flx/specification
Noctua has few db lower noise according to specsheets, which is likely due to difference with speed?
At the same speed (or CFM) the sound power is barely the same but a tad lower in frequency with the Papst, resulting a much lower percivied sound to my experience.
Yeah lower pitch noise would reduce audibility, fans are really quite annoying in a small room and if possible to eliminate one should.
How easy it is to change speed of such fan, if by default noctua runs lower speed (?) out of the box and thus has bit less noise is it worth it to use Papts with speed control? On the other hand speed control could reduce noise even further, so perhaps would be good with any fan. One could drop speed as low as feasible for a given piece of equipment, or even better make it temperature controlled.
How easy it is to change speed of such fan, if by default noctua runs lower speed (?) out of the box and thus has bit less noise is it worth it to use Papts with speed control? On the other hand speed control could reduce noise even further, so perhaps would be good with any fan. One could drop speed as low as feasible for a given piece of equipment, or even better make it temperature controlled.
I use them on a printer head prototype that have an embedded adjustable voltage regulator that allow me to use any fan and obtain the same CFM and pressure, it is the only fan on the pinter.
The noctua is silent but a tad annoying when i enter the room, the papst is louder un the lows but a lot less annoying in the MF.
The noctua is silent but a tad annoying when i enter the room, the papst is louder un the lows but a lot less annoying in the MF.