AudioCircle

Industry Circles => GR Research => Topic started by: openbaffled on 29 Mar 2018, 08:13 pm

Title: GR servo sub + Rythmik servo amp - Feedback Level?
Post by: openbaffled on 29 Mar 2018, 08:13 pm

My interest is in OB servo subs in the famous Hemo flat pack H frames.  I'm coming from a diy accelerometer servo 12" sealed.  As I understand it, there is no easy way to look at the frequency response of an OB speaker because the room is so involved.  Possibly close miked would get you an idea, but I haven't seen any frequency response data for the GR OB servo sub.  Is that available?  I would like to see some data just to help me understand the the chosen tuning.

The closest I have come is to look at Rythmik's site where they show a sealed box servo sub using the GR driver.  From that data, I would guess that the feedback is at a mid-level, maybe 6 dB, because the phase at both -3 dB points is pretty conservative.  Am I understanding this correctly?

Thanks in advance.

Jac

Title: Re: GR servo sub + Rythmik servo amp - Feedback Level?
Post by: Danny Richie on 29 Mar 2018, 08:21 pm

Quote from: openbaffled on 29 Mar 2018, 08:13 pm

My interest is in OB servo subs in the famous Hemo flat pack H frames.  I'm coming from a diy accelerometer servo 12" sealed.  As I understand it, there is no easy way to look at the frequency response of an OB speaker because the room is so involved.  Possibly close miked would get you an idea, but I haven't seen any frequency response data for the GR OB servo sub.  Is that available?  I would like to see some data just to help me understand the the chosen tuning.

The closest I have come is to look at Rythmik's site where they show a sealed box servo sub using the GR driver.  From that data, I would guess that the feedback is at a mid-level, maybe 6 dB, because the phase at both -3 dB points is pretty conservative.  Am I understanding this correctly?

Thanks in advance.

Jac

Hey Jac,

Performance has come a long way from the old accelerometer based servo control.

I can and have measured the response of our servo subs. If I am measuring it then it is typically near field and it is to see the effect of the extension filter, damping, or crossover control functions. The response can easily be anything you want it to be. They can easily play flat to 20Hz and hit -3db levels in the teens. And that can be done in a sealed box or open baffle.

Title: Re: GR servo sub + Rythmik servo amp - Feedback Level?
Post by: openbaffled on 29 Mar 2018, 10:36 pm

Any curves you would care to share?

Title: Re: GR servo sub + Rythmik servo amp - Feedback Level?
Post by: Danny Richie on 30 Mar 2018, 01:59 am

Quote from: openbaffled on 29 Mar 2018, 10:36 pm

Any curves you would care to share?

I can post some tomorrow when I get back to the office. But you can literally make them do anything you want.