Are servo subs better?

[oldtexasdog 2,461]

Been reading reviews and specs on servo subs and was wondering if they were really better?

Thoughts?

[4krow 6,640]

There is probably more than one opinion about this, but I will give mine here. I have owned several types of subs, both active and not. Probably my all time favorite is a folded bass horn for its speed and impact, not to mention rock bottom depth. With that as a reference, only servo based subs have come close to that level of performance. To go a bit further, there is more than one servo based design out there, one claiming to be better than the other.  I do not have a solid preference that way.

[BarryG 2,853]

I am considering building an open baffle servo sub!

maybe one like this! 
https://www.gr-research.com/store/p22/Servo_Sub_Kit_4.html

 

there is a triple version pictured below! Courtesy of a GR-Research Thread on Audiocircle!

 

I really like the open Baffle sound!

 

barry

 

Edited November 2, 2020 by BarryG

[PMAT 2,042]

I assume you mean for music not home theater. They are different requirements. If I were purchasing some I would use the GR research subs. They are servo and many many people swear by them. For music that is. That is an open baffle bass alignment. you can also get them sealed or ported. That would be the same manufacturer, Rhythmic Audio which produces the GR research units and amplifiers that are required. We have a member here Perry who has more experience with this system.

Edited November 2, 2020 by PMAT
Sp

[BarryG 2,853]

Definitely for two channel audio.  I have little interest in home theater!  A sealed sub is definitely better for home theater!

 

barry

[oldtexasdog 2,461]

Well a conundrum?? My subs do a double duty for HT and music.

Form factor or should I say WAF factor is important also. Smaller box the better.

Edited November 2, 2020 by oldtexasdog

[BarryG 2,853]

WAF not an issue!
traded the wife for ALS years ago.  Not a problem for me!🥴

Edited November 2, 2020 by BarryG

[Dadvw 2,878]

2 hours ago, oldtexasdog said:

Well a conundrum?? My subs do a double duty for HT and music.

Form factor or should I say WAF factor is important also. Smaller box the better.

I understand OTD! With speakers WAF is important, gear, not so much.........grin

[elgrau 89]

Interested but no knowledge of....

 

Thought of servo drive back when I was building my spherical speakers re considered driving the entire "segmented" spherical surface sans drivers. But too many issues with this, and I guess servos just cannot respond fast enough for mids or highs (although, technically one could consider the standard speaker VC driver a kind of "servo")... Settled for a symmetrically arranged around the sphere configuration of 8 tweeters and 6 woofers as a good compromise and MUCH easier (and possible..) to build.

 

The advantage of a servo (IMO/understanding) is that it removes the distortion of the dynamic response of the simple mass/spring system that the driver cone and supporting surround spring are and is produced as they try and "do their own thing" on top of their forced response from the driving force of the VC. A servo directly mechanically connected (as opposed to the VC which is only responding to a magnetic force) FORCES the cone to move ONLY exactly as the music signal dictates and no transient response MOTIONS from the dynamics of this system are allowed. But obviously, servo driven speaker cones would be much more expensive and would also need a "box" to convert the amplified music signal to a proportional linear motion of the servo, as opposed to a magnetic force that is easy-peasy in comparison and just the physics of magnets and coils and electrical voltages and no mechanical links (friction, free play, etc., etc.) to the speaker cone to worry about that perhaps degrade servo driven subs and represent one of their "tradeoffs"?

Edited November 2, 2020 by elgrau

[Daddyjt 9,648]

8 hours ago, oldtexasdog said:

Well a conundrum?? My subs do a double duty for HT and music.

Form factor or should I say WAF factor is important also. Smaller box the better.

There is no conundrum James - while it is true that the benefits of a servo system will be most readily apparent in a 2ch system, the benefits to an HT system are also significant. Especially in extreme deep bass tracks (Think U571 or Saving Private Ryan).  In those extreme moments, even the most powerful subs tend to lose control of the cone - especially in 15” & 18” diameters. The servo really helps control the “flab” as I call it, when the sub surrenders control and just starts making noise.