Acoustics of drivers back space

[jeno]

Hello, and happy holidays to everyone.

I have question I have given some thought. I have done a lot of reading on this forum, but haven't found the answer to my question. Please point me to the right direction if there is something I have been overlooking.

How will the acoustics of the back space of the drivers affect the performance of an IB sub? Should one pay as much attention to standing waves/room modes etc in the back space as in the listening room?

Please explain why/why not.

Best regards
Jan

[ThomasW]

Dec 25, 2012 6:05:31 GMT -7 jeno said:

How will the acoustics of the back space of the drivers affect the performance of an IB sub?

As is explained in the FAQ, if there's 10X Vas of space for the rear wave, the acoustic characteristics of rear space has virtually no impact on the performance of the driver.

Standing waves or room anomalies in one room or area don't/can't/won't impact the operation of the driver in the other space. Those things are specific to the acoustic space where they occur.

[jeno]

Thanks for your reply.

Then I guess I can stop worrying about that and maybe rather build something.

Jan

[FOH]

It's a good question really.



However, this;

"if there's 10X Vas of space for the rear wave, the acoustic characteristics of rear space has virtually no impact on the performance of the driver."

Should be shouted from the roof tops .... as it's the entire "Raison d'être" behind the pursuing the IB approach,..ie., the alignment has virtually no impact on the driver.



In a somewhat different topic, I am interested in how the immediate surroundings impact the driver's output, even in a full 10x VAS environment. I've read others mention it in previous discussions, and how minimizing energy off the adjacent surfaces is a step worthy of pursuing. Clearly, that makes sense, I'm just curious how impactful, etc.

Fortunately, I don't have to deal with such an issue, but it does seem to come up in build threads.

[ThomasW]

Dec 26, 2012 17:55:25 GMT -7 FOH said:

In a somewhat different topic, I am interested in how the immediate surroundings impact the driver's output, even in a full 10x VAS environment. I've read others mention it in previous discussions, and how minimizing energy off the adjacent surfaces is a step worthy of pursuing. Clearly, that makes sense, I'm just curious how impactful, etc.

Objects behind the woofers aren't a big deal. Problems arise when there are larger flat surfaces close by, (walls, etc), those should be covered with a layer of fiberglass batting, Roxul, or similar

[FOH]

That's exactly the immediate surroundings" I'm referring to

[Ile]

I found out that adding wool to back space didn't effect much to freq response in listening position, but it affect to spectral decay that is good thing.

My back space is under 10 x vas though and all surfaces are concrete with same width and depth dimension.