ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2  All   Go Down

Author Topic: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version  (Read 875 times)

Pat Semeraro

  • Newbie
  • *
  • Offline Offline
  • Posts: 12

All of this talk about limiting and level matching seems very confusing!  Subs should always be run from an aux.  Adjust the volume until its correct, done.  Limiting should be captive, i.e. manufacture's box and manufacturer's dsp.  I'm sure that JBL must have captive settings for Crown I-tech amps and maybe others.  (LAB, Powersoft?) As an EAW user, its super simple, select the correct box on the UX8800, input the amp sensitivity and power, and dsp deals with thermal and excursion for the drivers.  Not saying EAW is the last word, (everyone likes what they like) but for highly abusive, night after night, rig absolutely cannot fail performance, we've been trouble free for years.  10,000 people outdoors and techno/dubstep warbles that can be felt from 1000 feet away and no failures and no stress while operating.  Put the pedal down and the system does its thing.  How can you expect to squeeze out the last .5 dB of clean level and never blow up a driver if you're guessing at limiter settings?  AND, limiting is not the same at all frequencies, and hi-pass should slide up as level goes up to control excursion.  Seems like basic arbitrary limiting is begging for failure or leaving lots of output on the table?  Amp, dsp, and box are a sacred system that only the manufacturer can set up correctly.

I've always liked the way JBL subs do kick drums - set up correctly they will punch you in the face.  We use EAW SB528z which are 27HZ boxes.  Big cabinets... but a pile of them will rip out your intestines down in the 20s.  Wasteful for R&R but perfect for electronic music.

Having my gear intact at the end of the night is obviously the more important thing here. Would having the peak voltage at the program rating really be that likely to harm the subs? I appreciate your wisdom and insight on this matter, Ivan!

Please see the attached revision. Do the release and attack times for the RMS (thermal) limiter look in line with what they should be?
« Last Edit: December 24, 2017, 12:31:05 am by Pat Semeraro »
Logged

Spenser Hamilton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 605
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #1 on: November 12, 2017, 12:27:35 pm »

Subs should always be run from an aux.

You sure about that?  ???

Quote
I've always liked the way JBL subs do kick drums - set up correctly the will punch you in the face.  We use EAW SB528z which are 27HZ boxes.  Big cabinets... but a pile of them will rip out your intestines down in the 20s.  Wasteful for R&R but perfect for electronic music.

EAWs own specs indicate that the processed response is down 10dB at 27Hz, unprocessed pushes the -10 point even higher.
Logged

Luke Geis

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1158
    • Owner of Endever Music Production's
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #2 on: November 12, 2017, 02:35:26 pm »

I think we may have lost sight of what a PA is in general. Forget about DSP, limiting and speaker specs. What is a PA supposed to do?

1. Reproduce sound accurately and or as intended

2. To produce that sound at the needed SPL at all the desired places of needed coverage

That pretty much sums up what a PA is supposed to do. How it does it is where DSP and basic design comes in. As a rule I feel that NO limiting or protections should be needed for the purpose of designing and implementing a PA system. Why? Because if properly designed, a PA system should not have the need to ever protect itself. A system designer should have designed a system that is spec'd to do the job within the systems abilities. If you go out with a system that you are within a few db's of its max spec, what do you expect to happen? It is probably going to not be happy and all the red lights are going to be saying save me.

I feel that the source sound is the only thing that should determine the sound of a PA. If you want to pump un-compressed live audio through a PA at 140db then you better have a PA that is capable of producing at least 155db and preferably more!!!! If you want 140db of highly processed and compressed live audio ( call it commercialized live audio ), then you may not need a PA system that is capable of 155db to do it, you can probably use one that is closer to 145db and possibly get away with it. The point being that the source is a huge determining factor in a systems probable outcome.

So as we come to the reality of what a system is actually capable of, and we understand what we are trying to reproduce with it, we shoudl know pretty quickly if we have a systems that is within its abilities, or not. The last factor that many don't think about is the amount of time the system has to work at the desired SPL. If you are running close to a PA's limits, then you are going to be allotted a shorter duty cycle. A PA that is over spec'd will run along all day and all night with nearly an unlimited duty cycle ( not actually, but you get the point ).

If you are at the venue and you are trying to sort the amount and type of limiting in order to keep the system intact, you likely didn't bring enough rig for the gig. With modern DSP it is nearly point and shoot. If you are worried about blowing things up, then double down and or keep things in check from the source. If the engineer wants 140db out of a PA capable of only 130db, then you will have to put the engineer in check.

Specs are just a reference to the ability of a unit in a system. If you intend on altering the basic specs to meet you desires, you will have to get good at robing Peter to pay Paul. The spec doesn't change per se, all you are doing is altering the outcome. If you ask for more than something has to give, you did it wrong. You can cheat a little for a little bit, but you can't cheat a lot for very long.
Logged
I don't understand how you can't hear your self

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 17995
  • Wichita, Kansas USA
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #3 on: November 12, 2017, 07:11:06 pm »

This was a Zombie Thread until Pat Semararo revived it.

Getting the last couple of useful dB from a system without unduly risking damage to it is how I make my living.  There are very few shows where I can get the promoter to pay for "luxury headroom" if it's not accompanied by more coverage (more ticket sales).  YMMV.
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

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 8301
  • Atlanta GA
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #4 on: November 12, 2017, 07:40:21 pm »

This was a Zombie Thread until Pat Semararo revived it.

Getting the last couple of useful dB from a system without unduly risking damage to it is how I make my living.  There are very few shows where I can get the promoter to pay for "luxury headroom" if it's not accompanied by more coverage (more ticket sales).  YMMV.
Agreed.

And when you "start digging" it gets a bit more complicated real quick.

A lot (let's say most?) FOH guys don't mix for a particular SPL, but rather for a particular "sound".

Sometimes that is a particular feeling in the chest/body cavity.  Other times it is for a specific amount of distortion-YES it is very common that people will simply keep cranking it up until it "sounds" right to them-ie distortion.

Let's say the "spec" is 120dB C slow.  But good luck getting any weighting or speed.

If the system is clean at 120, they may just keep cranking until it starts to distort the way they want.  That might be 130dB, beyond the capability of the system.

But if the system was distorting around 115dB, they would probably stop and be happy with the SPL.

The same goes for the low end.  If the room is real "swampy", it can be real hard to get a nice tight low end punch.  So the levels just keep going up and up.

But in a "good tight" room, you can get the required "feeling" at a lower SPL.

As usual-it depends, and simple SPL numbers don't tell the whole story.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Scott Holtzman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4194
  • Ghost AV - Avon Lake, OH
    • Ghost Audio Visual Systems, LLC
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #5 on: November 12, 2017, 07:41:36 pm »

This was a Zombie Thread until Pat Semararo revived it.

Getting the last couple of useful dB from a system without unduly risking damage to it is how I make my living.  There are very few shows where I can get the promoter to pay for "luxury headroom" if it's not accompanied by more coverage (more ticket sales).  YMMV.
True Tim but you don't destroy the PA in the process.

It takes a lot of experience, experience won by blowing shit up, to know what you can get away with.



Sent from my VS995 using Tapatalk

Logged
Scott AKA "Skyking" Holtzman
River Delta Audio is now:

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 8301
  • Atlanta GA
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #6 on: November 12, 2017, 08:43:02 pm »

True Tim but you don't destroy the PA in the process.

It takes a lot of experience, experience won by blowing shit up, to know what you can get away with.



Sent from my VS995 using Tapatalk
I love the comment from people who say they have been running systems for years and then finally a loudspeaker burns up.

"Back in the day", tearing up drivers was just "par for the course".

It was almost expected to tear up 1 or more drivers during a show.

The reason I got into reconing was to save myself money :)

I can't remember how many hundreds of drivers I have torn up.

And I have stories of "accidents" that took out all of the drivers in a particular freq band.

Of course you learn A LOT in the process.  That knowledge has helped me later in life, to help others from not having to have the same hard learning curve that I went through.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 17995
  • Wichita, Kansas USA
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #7 on: November 12, 2017, 11:44:09 pm »

True Tim but you don't destroy the PA in the process.

It takes a lot of experience, experience won by blowing shit up, to know what you can get away with.



Sent from my VS995 using Tapatalk

Yeah, finding the 'other side of the razor's edge' was a common thing.  I spent some coin on tuition at Ye Olde Skool of Harde Knox® learning what to not do...

I love the comment from people who say they have been running systems for years and then finally a loudspeaker burns up.

"Back in the day", tearing up drivers was just "par for the course".

It was almost expected to tear up 1 or more drivers during a show.

The reason I got into reconing was to save myself money :)

I can't remember how many hundreds of drivers I have torn up.

And I have stories of "accidents" that took out all of the drivers in a particular freq band.

Of course you learn A LOT in the process.  That knowledge has helped me later in life, to help others from not having to have the same hard learning curve that I went through.

Yep, and we still benefit from what we learned 30-40 years ago and I agree that it should not be necessary for the young 'uns to repeat our mistakes...  I *do* encourage them to blow up speakers and fry power amps, though... at least a couple times. 8)
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

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 8301
  • Atlanta GA
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #8 on: November 13, 2017, 07:44:44 am »

Yeah, finding the 'other side of the razor's edge' was a common thing.  I spent some coin on tuition at Ye Olde Skool of Harde Knox® learning what to not do...

Yep, and we still benefit from what we learned 30-40 years ago and I agree that it should not be necessary for the young 'uns to repeat our mistakes...  I *do* encourage them to blow up speakers and fry power amps, though... at least a couple times. 8)
The problem is many people think they can simply "turn it up" all they want and nothing should happen.

NO, there are limits and it is actually pretty easy to tear up loudspeakers and overheat amplifiers.

That seems to surprise some people
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Gordon Brinton

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 396
  • ID Verified
    • Raw Depth Sound, Harrisburg, PA
Re: Re: JBL's New SRX800 Series Subs - How do they compare? 2017 version
« Reply #9 on: November 14, 2017, 07:38:24 am »

I think we may have lost sight of what a PA is in general. Forget about DSP, limiting and speaker specs. What is a PA supposed to do?

1. Reproduce sound accurately and or as intended.

I disagree with this...at least in the low-end frequencies.

At a live rock show, patrons want to feel the kick drum punch them in the chest. They want to feel the bass guitar vibrate the floor beneath their feet. That's why they move closer to the stage. That power and excitement is part of the experience.

The low-end needs to be somewhat enhanced or "exaggerated" with EQ and compression in order to deliver that feeling of huge power.

Have you ever heard a kick drum with no amplification? It's pretty lifeless unless your ear is right down in front of it. In my opinion, the PA system's job is to enhance and improve.

EDIT: In the smaller, low-budget, weekend realm, we need to use what we can afford. Sometimes we need to push it to near its limits. Thus, we rely more heavily on DSP control.
« Last Edit: November 14, 2017, 07:46:03 am by Gordon Brinton »
Logged
Member since 2005.
Pages: [1] 2  All   Go Up
 


Page created in 0.042 seconds with 20 queries.