VMPS Subwoofer Tuning (1 Viewer)

[ShalM]

Hi,

This is a newbie question seeking help and info. I wanted to get opinions on how to tune (change mass load) a passive radiator on a VMPS subwoofer which has a 12 inch active and 15 inch passive radiator in a sealed box. Any guidance, pointers, advice to do it the right way would be appreciated.

Also curious if people had any thoughts on VMPS subwoofers in general. This is DIY forum, but VMPS does sell kits and so was wondering if any other users had any experience.

Thanks.

 

[ThomasW]

That sub design has been around quite a while. And Cheney is pretty good at optimizing performance. What are you trying to achieve?
Also did you know there is a VMPS forum?
http://www.harmonicdiscord.com/forum...p?forum=22&975

 

[ShalM]

Hi Thomas,

Thanks for replying to my post. I actually have been using the VMPS sub for quite sometime now and never really got around to playing with the mass loading of the passive radiator. I have heard that it can make a significant difference and so was looking for some pointers and guidance as to whats the best way to do it, so that I could get the best out of it.

Would appreciate any suggestions in that regard.

Also there is so much talk about SVS subwoofers around here, so was curious if any other members had ever had a chance to compare the VMPS original subwoofer as they were/are supposedly one of the good subwoofers around.

Thanks for the link to the other forum and will try to communicate with brian also.

 

[ThomasW]

Well the basic idea is that as mass is added to the PR it lowers the box tuning. It's pretty handy to know the initial weight of the PR before you start playing around. I know that Brian doesn't disclose a lot of specs about the individual items he uses.

 

[ShalM]

Thank you for clearing the idea of mass loading. So, the way you tell me, amount of mass loading would be inverse to output and proportional to low frequency extension. Did I understand that right?

I dont have an idea how much the PR weighs and how much loading is there on it. I have sent an email to brian also and will see how much help I get.

Should I just try to decrease the mass loading and see what kind of output I get using a test tone and SPL meter ?

Thanks again.