Goldwood GW-215/4 OB sub-woofer?

[Giri]

I simulated a four Goldwood GW-215/4 with four 15" driver per side, in a series-parallel configuration, in Basta. I have attached are the pictures of the simulation.

1) Is the xmax of 3.5mm a matter of concern? What is the xlim of Goldwood GW-215/4?

2) Please let know any observations or comments on the design, its feasibility, improvements etc.

 

[chris661]

How loud do you want to go?
OB bass is very lossy, but does have some advantages with regards to room interaction.

I wouldn't worry about Xmax so much as how gracefully the driver approaches and exceeds Xmax.

Chris

 

[scottjoplin]

OB bass is very lossy, but does have some advantages with regards to room interaction.

Yes, slightly less big box interaction, much less small box interaction

 

[Giri]

How loud do you want to go?
OB bass is very lossy, but does have some advantages with regards to room interaction.

I wouldn't worry about Xmax so much as how gracefully the driver approaches and exceeds Xmax.

Chris

I am worried about damaging the driver at volumes that cross the xlim more than any distortion

 

[Giri]

Yes, slightly less big box interaction, much less small box interaction

More like zero small box interaction

 

[chris661]

I am worried about damaging the driver at volumes that cross the xlim more than any distortion

Fair enough. That does come back to my question, though - how loud do you want to go?

You might find it's impossible to hit Xlim - it's rare to find a driver that will actually let you bottom it out as most tend to run out of motor force towards the ends of excursions, plus the surround/suspension is starting to lock up. The result is that the cone simply won't go any further, no matter how much power you drop in.

Chris

 

[Giri]

Fair enough. That does come back to my question, though - how loud do you want to go?

You might find it's impossible to hit Xlim - it's rare to find a driver that will actually let you bottom it out as most tend to run out of motor force towards the ends of excursions, plus the surround/suspension is starting to lock up. The result is that the cone simply won't go any further, no matter how much power you drop in.

Chris

I have seen internet pictures of some cones broken due to cone exertion beyond limits. Hence, the concern.

 

[chris661]

That's almost certainly down to PA usage. In a HiFi situation, if it sounds bad you'll turn it down. In a PA situation, you want every last bit of output and treat the speakers accordingly.

Chris

 

[scottjoplin]

You could lower the excursion requirements by using an H or U frame

 

[Giri]

You could lower the excursion requirements by using an H or U frame

I'm considering a H-frame or a V-Frame