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Author Topic: Things that make you go hmmmm....  (Read 10012 times)

Scott Carneval

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Things that make you go hmmmm....
« on: May 04, 2016, 03:48:42 PM »

So let's say I have a perfectly phase-aligned system. The subs are even flown with the tops, so it's aligned relatively well throughout the entire venue.  The subs are run 15-20 db hotter than the tops, and they are aligned through the ACOUSTICAL crossover point. I know, I'm living in a perfect world here, but bear with me.

Now I crank the system up. The subs are run hotter, and they hit the limiters first. Now my subs are putting out LESS output relative to my tops. This changes my acoustical crossover point.

HMMMMMM.....
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Roland Clarke

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Re: Things that make you go hmmmm....
« Reply #1 on: May 04, 2016, 04:18:11 PM »

So let's say I have a perfectly phase-aligned system. The subs are even flown with the tops, so it's aligned relatively well throughout the entire venue.  The subs are run 15-20 db hotter than the tops, and they are aligned through the ACOUSTICAL crossover point. I know, I'm living in a perfect world here, but bear with me.

Now I crank the system up. The subs are run hotter, and they hit the limiters first. Now my subs are putting out LESS output relative to my tops. This changes my acoustical crossover point.

HMMMMMM.....

Simple!

Not enough rig for your particular gig.

Why you would want to run subs 4 x as loud as the rest of the rig beats me, with this sort of set-up getting it all time aligned is the least of the problems.
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Scott Carneval

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Re: Things that make you go hmmmm....
« Reply #2 on: May 04, 2016, 04:19:51 PM »

I guess you've never provided for a hip-hop or EDM show.


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Roland Clarke

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Re: Things that make you go hmmmm....
« Reply #3 on: May 04, 2016, 04:48:01 PM »

I guess you've never provided for a hip-hop or EDM show.


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No, but plenty of the major suppliers do and manage without too many issues.   For starters why fly the subs?  If you want to "overdo" the bass ground stack will give you more for free.  As rigs go up in size your ratios of subs to tops changes.  Also, as you hit your spl limits, you tops should be left with power to spare.

 If, as you say, you are hitting you sub max, as mentioned above, you don't have enough rig, and if you have enough rig you are going to get shut down before you hit the limit.
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Brian Jojade

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Re: Things that make you go hmmmm....
« Reply #4 on: May 04, 2016, 04:52:23 PM »

If at any point during the show, under normal circumstances, you hit a system limiter, you simply don't have enough rig for the gig. Period.  A limiter should be there as an 'oh shit' protection. How the system behaves beyond hitting the limiter doesn't really matter, as you shouldn't be there during the show anyway.
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Scott Helmke

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Re: Things that make you go hmmmm....
« Reply #5 on: May 04, 2016, 05:54:25 PM »

Now I crank the system up. The subs are run hotter, and they hit the limiters first. Now my subs are putting out LESS output relative to my tops. This changes my acoustical crossover point.

Same thing happens when you use aux-fed subs. Per source, to make it even more interesting.
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Spenser Hamilton

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Re: Things that make you go hmmmm....
« Reply #6 on: May 04, 2016, 07:44:11 PM »

For starters why fly the subs?  If you want to "overdo" the bass ground stack will give you more for free.

I think Ivan will disagree with this.
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David Sturzenbecher

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Re: Things that make you go hmmmm....
« Reply #7 on: May 04, 2016, 08:10:15 PM »

This is no different then hitting the limiters of any band on any multiway system. Powered speakers, conventional, point source, line array.  No system is immune to being driven out of alignment.... Unless you limit the entire signal before the frequency division. Insert weakest link comment here.


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Scott Carneval

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Re: Things that make you go hmmmm....
« Reply #8 on: May 04, 2016, 08:29:25 PM »

Same thing happens when you use aux-fed subs. Per source, to make it even more interesting.
Not if you run your aux at unity and adjust the level with the channel fader. This way your subs and tops are being sent a proportional level.
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Scott Carneval

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Re: Things that make you go hmmmm....
« Reply #9 on: May 04, 2016, 08:38:34 PM »

For starters why fly the subs?  If you want to "overdo" the bass ground stack will give you more for free.

Flying the subs will give you more even coverage from front to back, AND it will allow you to keep the subs/tops in alignment from front to back. You sacrifice a little bass up close to the stage, but if you have enough Rig for the Gig you can just turn it up more if needed.

Quote
If, as you say, you are hitting you sub max, as mentioned above, you don't have enough rig, and if you have enough rig you are going to get shut down before you hit the limit.

I agree. But we've all been on gigs where we've had to run the system up against the limiter or had a guest engineer do it for you.

I just thought it was interesting. I was running through a system alignment this afternoon and it sort of dawned on me, and I don't think it's something that's ever been discussed here. Just one more reason to keep the system out of the limiters...
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ProSoundWeb Community

Re: Things that make you go hmmmm....
« Reply #9 on: May 04, 2016, 08:38:34 PM »


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