ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: Speaker Protection  (Read 3280 times)

Jeff Bankston

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2398
Speaker Protection
« on: January 03, 2012, 05:02:06 am »

anyone use a drawmer sp2120 speaker protector in a pa used for live hard rock band ? would this work as good as a limiter to keep sudden peaks from blowing speakers when the system is close to or at maxium output ?
« Last Edit: January 03, 2012, 05:07:14 am by Jeff Harrell »
Logged

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6807
  • Boston, MA USA
Re: Speaker Protection
« Reply #1 on: January 03, 2012, 08:33:39 am »

Jeff,
I am not totally against so called "speaker protection" devices. They have a use when rentals are provided, when an untrained BE may mix, or for DJs and other less trained persons. In the real world devices of this type may minimize damage, however, I am unaware of any device that can and will totally eliminate the possability of damage to components.

What will eliminate damage to components is a properly assmbled, matched, and tuned system, a properly set gain structure, and an operator who is capable of working within the systems limits.

With that being said brick wall limiters are available and if you feel the need to place one of those in line with the system you might start with more commonly used hardware. The Aphex Dominator and the Drawmer 2120, which is new to the market, both come to mind as some of the better units available. The Drawmer is about $600 less than the Dominator, but the 2120 is to me an unproven unit where as the Dominator has been around and has been used by many people for many years.

http://www.drawmer.com/products/protection/sp2120-speaker-protector.php

http://www.aphex.com/products/720-dominator/


 
Logged
BOSTON STRONG........
Proud Vietnam Veteran

I did a gig for Otis Elevator once. Like every job, it had it's ups and downs.

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16624
  • Hickory, Mississippi, USA
    • Resotune
Re: Speaker Protection
« Reply #2 on: January 03, 2012, 10:50:44 am »

I am not opposed to the concept, and that Drawmer piece looks like it's aimed at fixed install (like bars or clubs) to protect installed speaker systems from operator abuse.

The same tension we deal with when sizing amps to work with speaker power handling , rears it's ugly head when it comes to effective, and transparent speaker protection.

Ideally the protection would sense, or calculate, temperature rise in the loudspeaker voice coils and change limiting behavior based on that reality. To get the best result requires complicated protection algorithms (designed for given box loads), and closed loop sensing.

None of these come neatly and easily. I should be sounding like a broken record by now, but this is best handled inside powered loudspeakers, by powered loudspeaker design engineers.

Note: that Drawmer piece has some nice flashy lights, and the classic DJ mixer trick, where you trim the output level down so the front meters show max, for whatever "system" level you select.

JR
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 21573
  • Wichita, Kansas USA
Re: Speaker Protection
« Reply #3 on: January 03, 2012, 03:22:49 pm »

anyone use a drawmer sp2120 speaker protector in a pa used for live hard rock band ? would this work as good as a limiter to keep sudden peaks from blowing speakers when the system is close to or at maxium output ?

So are you looking for "catastrophic disaster" protection, like the lead singer's KSM9 getting unplugged with the PA at Full Tilt Boogie, or is this for the heavy-handed BE that is running the rig without headroom?

The best, but most expensive way to deal with the latter is "bring Enough Rig for the Gig«".  There are some BEs that will never have enough PA or enough subs.  What you're looking for is a way to deal with a BE without actually interacting with him/her personally.  Frankly, most of them will not be offended if you talk about operational levels and the safety of the rig before sound check.  Then if you hear or see your rig getting pushed to the point that something is in danger, just let them know they're over the previously discussed line.

Surprising them during the show will likely lead to frowns. :(

If the situation is more about those "oh, shit!" moments, then I suggest you need to look at the processing much closer to the speaker.  You use I-Techs, right?  That is where your long term power limiting and "oh shit" peak limiting are best applied.  In designing your protection, begin with proper HPF and remember that most professional speaker system cone drivers die from heat, not mechanical failure.  Compression drivers in correctly band-passed systems generally don't fail for mechanical reasons, but it does happen; again the most common failure mode is heat.  For a limiter to be effective, it would require a *very* quick attack time (microseconds, not milliseconds) and at least 20dB of reduction.  The threshold would need to be high enough to not trigger with program material.

I think JR and Ivan went over this several times in previous iterations of the PSW forums.  System component protection isn't something that comes in "simple but effective" flavors just yet.  I suggest a search.
Logged
"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Jeff Bankston

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2398
Re: Speaker Protection
« Reply #4 on: January 03, 2012, 03:57:41 pm »

So are you looking for "catastrophic disaster" protection, like the lead singer's KSM9 getting unplugged with the PA at Full Tilt Boogie, or is this for the heavy-handed BE that is running the rig without headroom?

The best, but most expensive way to deal with the latter is "bring Enough Rig for the Gig«".  There are some BEs that will never have enough PA or enough subs.  What you're looking for is a way to deal with a BE without actually interacting with him/her personally.  Frankly, most of them will not be offended if you talk about operational levels and the safety of the rig before sound check.  Then if you hear or see your rig getting pushed to the point that something is in danger, just let them know they're over the previously discussed line.

Surprising them during the show will likely lead to frowns. :(

If the situation is more about those "oh, shit!" moments, then I suggest you need to look at the processing much closer to the speaker.  You use I-Techs, right? 
i have qsc series 3 models 3800(low) and 3500(mid-high). i was looking at compressor/limiters and saw the drawmer speaker protector and that got me to thinking if its something that i should have in the system just in case. i'v got plenty of power and the speakers are matched to the amps. i play drums and there are times when i kick the bass drum a little harder and hit the toms a little harder on a few songs. i also sing. never had a problem and never saw one of these speaker protectors b 4. a friend thats a drummer and worked at a tour sound company runs the pa. i'm in the process of building new speakers and am using the new faitalpro 18xl1600 4 ohm that just hit the market , ciare 12ndh4. i will be reusing my beyma 2" compression drivers. the system was never pushed to the limit b 4 clip. thanks for the replys.
« Last Edit: January 03, 2012, 04:23:17 pm by Jeff Harrell »
Logged

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16624
  • Hickory, Mississippi, USA
    • Resotune
Re: Speaker Protection
« Reply #5 on: January 03, 2012, 04:55:23 pm »



 For a limiter to be effective, it would require a *very* quick attack time (microseconds, not milliseconds) and at least 20dB of reduction.  The threshold would need to be high enough to not trigger with program material.

I think JR and Ivan went over this several times in previous iterations of the PSW forums.  System component protection isn't something that comes in "simple but effective" flavors just yet.  I suggest a search.

+1, but in general the dominant thermal failure mechanism is relatively slow moving so to be transparent, that remedy can be relatively slow moving too. For mitigating against clipping overload the attack/release speed is always a compromise, as very fast gain change is indistinguishable from the clipping distortion we are trying to remedy. Different manufacturers have developed successful time constant strategies for amplifier clip-limiters over the decades these have been in general use. 

I vote for more rig, and slow limiting, while the hard part is accurately determining the thermal state of the sundry voice coils. More sophisticated limiting can factor in  driver/box tuning etc, and protect against mechanical over-excursion too, but this quickly gets far more complex than typical end users can process and deal with. Thus my advocacy for powered cabs. 


JR
Logged
Don't tune your drums half-ass. Listen to what a properly "cleared" drum sounds like.   http://circularscience.com/

ProSoundWeb Community

Re: Speaker Protection
┬ź Reply #5 on: January 03, 2012, 04:55:23 pm ┬╗


Pages: [1]   Go Up
 



Page created in 0.046 seconds with 23 queries.