Max db for ventilation fan

[OpIvy]

I'm stuck in the never-ending quest to find a suitable fan for ventilation of a 2mx2.4m vocal booth.
My plan is to build a baffle box outside of the booth to push fresh air in via insulated ducts but I'm finding decent inline fans are outrageously expensive.....here in Australia anyway.
But I'm mainly wondering how loud is too loud provided I isolate it in a suitable box.....how about max 30db?....<20db?

I'm willing to have slight noise as I'm far from pro!

Cheers

[John Steel]

Hello & howdo' Opivy?
I'm currently building a studio in SE England (1600 cu.ft) and recently bought an inline fan. I suppose a definition of 'outrageously expensive' is open to at least some interpretation but I have seen units rated at between 19dB > 24dB for £125 (plus tax) in the UK. I know it's worth researching these things thoroughly - the internet will, eventually, reveal all things given time & effort. I hope you find what you need affordably. Best wishes, John.

[OpIvy]

Well when I say 'outrageously' expensive, I meant relatively speaking. We tend to often pay a lot more for many things here. It's just that I've been finding many quiet inline fans (about max 24db) costing over $200AUD.
I've got a pretty tight budget so I'm looking at some cheaper models- more plastic, less features etc but they say max noise is around 30db.

I'm trying to imagine if that would be particularly loud when built into a suitable isolation box.
I also live in a regional area where it's difficult to go in a store and have a listen so will be buying online.

[John Steel]

Hello again Opivy,
I'm wondering if I have misunderstood your original post.

I'm trying to imagine if that would be particularly loud when built into a suitable isolation box.

I would not build a silencer with a fan inside it (silencers as I understand it are sealed units and unlikely to need repair before your fan does). I would put the fan after the exhaust silencer as this will create negative pressure in the booth (and pull the door into the seals). Do you have a plan (even a rough one) of what you want to build? ATB John.