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-   -   ISO box for guitar cabinet but no microphone needed (

PaulRain 29th October 2019 02:54 PM

ISO box for guitar cabinet but no microphone needed
I know there are tons of discussions in the web about ISO Boxes but I can't find much on what I was thinking.
Basically recently I'm recording electric guitars by putting a DI between the amp the the cab (the cab is connected)... I record what comes out from the amp, right before the cab, and then I use quality impulses in the daw.
The problem is the noise, pushing a 50W amp in his sweet spot is way too loud for my small home studio.
So, my idea is to build a sealed box with a speaker inside (10" 500Watt stupid cheap car speaker) to allow the amp to see the correct reactive load of a real speaker but silenced by the sealed and massive (I'm planning to use MDF and lead rubber sheets).
The box will be air-tight and my concern is about the air that the speaker is suppose to move which I believe will not really move much in a sealed (from and back) system.
ideas? thoughts? comments? tips? tricks?

Starlight 29th October 2019 03:54 PM


Originally Posted by PaulRain (Post 14291938)
ideas? thoughts? comments? tips? tricks?

For playing electric guitar live I use an attenuator that sits between the amp and the speaker in my combo. If a DI box was placed before the attenuator that should allow for the amp's sound to be split off via the DI box and then the volume attenuated, whether partially or fully, leaving the speaker to make a much quieter noise and in turn reduce the TL needed from an ISO box. It would require plenty of air to keep the attenuator from overheating.

RyanC 29th October 2019 04:36 PM

Something like this might be a good option-

You can bypass the cab sim, but use no cab at all (as I understand it). This way you can still use the IR's...I don't have any experience with it though, but it does have pretty good reviews.

PaulRain 30th October 2019 08:40 AM

thanks for the tips but I was really interested in building that thing :)

RyanC 30th October 2019 11:46 AM


Originally Posted by PaulRain (Post 14293644)
thanks for the tips but I was really interested in building that thing :)

Go for it-

In general to achieve the most isolation the same principles as studio isolation apply. Are you trying to isolate from the room you are in, next to it? Or from the rest of the house?

A few thoughts- lead/rubber sheets and MLV are widely regarded as overpriced and having no real isolation benefit compared to cheaper mass (drywall, MDF, OSB etc). Also one of biggest things for isolation is decoupling- depending on if this is going to be a single or double leaf design, the way you figure out how to decouple the inner leaf to the outer leaf, and then the whole box to the floor will likely be the biggest factor that determines how much isolation you get.

Also like a studio, the best 1st step is to determine how loud your source is, and how much isolation you need.

One thing to consider is that if this thing is really small and sealed up really well, it is going to get hot in there. A speaker driver has about 5% thermal efficiency- the rest going to heat. 45w is ~150btu...

PaulRain 30th October 2019 11:57 AM

I already have a roll of heavy rubber sheet leftover so I'm don't need to buy that :)
So, the first issue is not making the box too small, then decoupling as much as possible.