John Sayers' Recording Studio Design Forum Archive

Hi guys,

Just a quick question regarding the ventilation of the (closed and sealed) speaker boxes in my soffit mount construction. I couldn't get a proper air path from bottom to top in the right size. Therefore I bought fans for the ventilation. I am just not sure which pipes to choose to get air in and out of the box:
There are aluminum ones, that are quite sturdy, so I the advantage would be, that they will not be busted by the surrounding mineral wool. This would make me feel more secure about the air path staying stable. On the other hand, those aluminum pipes resonate, when you knock them. So, I am afraid, they might produce unwanted sound, as they are connected to the construction holding the speakers. On the other hand, they are behind a thick layer of mdf and plywood (4cm). And the vibration would be dampened by the mineral wool, so, I am not sure if this matters.
As an alternative, there are those pipes with plastic foil held by a coil of thin wire. These do not ring when you knock them, but are less robust, so I am afraid they might be compressed by the weight of the mineral wool.
Which pipes did you use for your soffit mounted speakers, if any were necessary?

Anyone? Maybe most people just build there soffits with chicken wire providing a clear air path from bottom to top. But I am sure someone else must have done some active ventilation ...

You don't really need to use actual pipes: the easiest way is to form a sort of "chimney" out of chicken wire before you put the insulation in. That keeps a path open through the insulation, which is all that you really need to do.

- Stuart -

Hi Stuart,

that was a misunderstanding. Due to the fact that I have PC ISO boxes under the speakers and some other problems I want to be sure the speakers do not overheat. Therefore, I decided to put fans in ind for those to work I actually do need a closed system from the point, where the fans are installed. So, I really need to put in pipes/duct. Do you happen to know which kinds of ducts I am talking about here?
These are the aluminum ones:

I already bought 2 of those, but after unwrapping them, I saw they where nasty resonators (when hitting them a little)! So I am afraid, they will get excited in certain frequencies, as they are connected with the speaker boxes. This might be a problem, but I am not sure, if it could be fixed by wrapping them in foam or something like that. Maybe, those resonances will be not so important behind the construction and insulation, but I don't want to take any chances here ...
So, since nobody replied before, I was thinking of buying another kind of duct available at my hardware store, which is a spiral wire, that holds a plastic coat. Similar to this one:

I would appreciate some input on that! Thanks!

I'd go with the flex duct (second picture). That's pretty much what it is designed for. But do make sure it doesn't get kinked during the installation: that can restrict the air flow, and create turbulence too. Keep it stretched tight and as straight as possible.

- Stuart -