Post by: Jim Schneider on November 30, 2010, 07:20:07 PM
I am wondering if anyone has any experience using the SR4719x subs with the DSC 260 processor. I recently did a gig with 4 of these boxes to cover an outside area of about 100ft x 75ft...I was told by a few people I needed more low end...the DJ was playing a lot of this Dubstep stuff amongst other names I never heard of or care,mainly cuz I am a live BAND guy. I placed the subs in front of the stage about 6inches apart and had some nice low end (hair moving and chest hurting) however, the DJ's said they wanted more sub-bass...would a BBE help out here or EQ'in a '+' dip in the eq to push the 30hz out...only thing is the box is tuned to 40hz...so forcing the box to do more then its intended low end is just asking for problems...any suggestions? currently using the JBL MPX1200 amps runing stereo at 1600w a side @ 2ohm. I bridged the amps then and ran them in 2ohm (yeah, I know bad idea) but it supposedly pushed the power to 3200w. Well, I am thinking of running a Macrotech 5002 on them all (stereo) and think I will get a lot more low end becuz its a Macrotech 5k and I have driven 4 sb1000's off of one and had nice results...
Also, would someone suggest moving to a Driverack for the processor?...I was just going to use a pip card in the Crown and call it Christmas...
-Jim
Post by: Elliot Thompson on November 30, 2010, 09:42:17 PM
Dubstep tends to be centred around 40 Hz so you do require more than four boxes if you want to attain more sub bass without losing your 4719s during the process.
Bear in mind Rave events require ample amounts of bass so renting four more 4719s should be helpful than trying to use a BBE Maxi miser.
Also the JBL MPX 1200 is a small amplifier in this day in age for bass. At 2 ohms per channel each driver is getting 400 watts. As far as I remember, the 2241 perform best at 600 watts.
The most I can tell you is to rent four more 4719’s (totalling eight) rent two MA 5002’s and offer a 12 dB per octave slope @ 30 Hz.
Best Regards,
Post by: Silas Pradetto on December 01, 2010, 11:41:47 AM
There is absolutely no way you were getting anywhere near 3200 watts out of those amps. You were running them equivalent to 1-ohm stereo, and there is NO WAY the current capability of the amp was high enough to produce the wattage you claim. Most likely, you were putting out LESS power than 2-ohm stereo due to the current limit.
Please get proper amps for your rig to use it to it's full potential. Also note, the 4719X is a rock sub, and probably doesn't go low enough for dubstep. You would need a LOT of them to do it, like Elliot said.
Even a Macrotech 5000 isn't quite enough to use those subs to their full potential in stereo. I'd want about 1000 watts per woofer or more (if properly limited, especially in your situation). I guess for dubstep the 600 per woofer or less would be appropriate.
Note that your DSP has NOTHING to do with your sub output. Run the proper high pass filter per JBL's specifications and you'll be fine. A different DSP will not help anything. Do NOT think you can lower the HP and have things still work; you'll quickly become familiar with the cost of reconing if you think you can do what you want and have it work.
Post by: Jim Schneider on December 01, 2010, 01:37:16 PM
I been mixing for quite some time and am definitely smart enough to know that the JBL sr4719x is a Rock N Roll type Box, front loaded normally was the first clue.
The power ratings I got from the MPX1200 amps was directly from their manual. (which I included) I never actually took the amp out, put a dummy load on it and actually measured actual power consumption with a meter, I do know how to do that though. I know the amps are a lil archaic but they are what I have for the system. Doing Bands on them in 250+ small inside clubs is plenty loud, but recently got toted into doing DJ stuff and outside. (oye vay)So as for the actual Setup, each 4719x is a 4ohm box. Paralleling 2 boxes makes it a 2ohm load. I have 2 of the MPX1200's. I originally was using just one mpx1200 running stereo. (so technically 2ohm per channel). I was clipping with low end so I turned it down...don't need a square wave to toast my drivers. The low end was ok for rock music...again...but just wasn't near what I needed for the DJ. (Amazing the Manual says PERFECT for the SR4719X Subs) So. I took another MPX1200 and bridged it mono. So now I have 2 MPX1200's MONO...each amp driving 2 4719s (2ohm load). The amps seem to be handling it and did do OK...but still, I know when blood is coming out of a turnip. Sooo....I do have a Macro 5002. I am likely going to put that on the subs and see if that beefs up the low end while running that in Stereo so I got 2 boxes a channel. I think the Damping Factor alone will tighten up the low end but I know I need more subs and amps. That is a given.
Now, for the DSP. The DSP actually controls the Limiter settings for the MPX1200 amps, so TECHNICALLY it does control the Sub output. If your processor isn't letting out the voltage, the amp can't do anything. P=IV...No V...No power. Not being sarcastic, just I went to college for Electrical Engineering and still remember a few things.
I really do appreciate both of your guys input. Me being one not living in the world of Tekno Music definitely has opened my eyes in the lows of lows. I wish I had a couple of Servo-Drive woofers and say ...take that you Baby Bottle Glow Stick Waving Kiddos! LOL...What is actually really funny is that at the last show, about half of the Kids dancing around all had EAR PLUGS in...then they keep telling me to turn it up...Ummm...something doesn't seem right here. Some of us Old Farts doing sound, yes I am 38, think if its too loud, turn it down. Ahh well. Any more input or comments are appreciated..Thanks again, take care my friends...
Post by: Silas Pradetto on December 01, 2010, 04:05:41 PM
| Jim Schneider wrote on Wed, 01 December 2010 13:37 |
Thanks Guys for responding...(Elliott and Silas) ... I never actually took the amp out, put a dummy load on it and actually measured actual power consumption with a meter, I do know how to do that though. ... |
Unfortunately, input power will tell you nothing about the output power, except that it's less than the input power...
| Quote: |
So as for the actual Setup, each 4719x is a 4ohm box. Paralleling 2 boxes makes it a 2ohm load. I have 2 of the MPX1200's. I originally was using just one mpx1200 running stereo. (so technically 2ohm per channel). I was clipping with low end so I turned it down...don't need a square wave to toast my drivers. |
Square waves never roasted any driver
| Quote: |
The low end was ok for rock music...again...but just wasn't near what I needed for the DJ. (Amazing the Manual says PERFECT for the SR4719X Subs) |
Ahhh, marketing...
| Quote: |
So. I took another MPX1200 and bridged it mono. So now I have 2 MPX1200's MONO...each amp driving 2 4719s (2ohm load). The amps seem to be handling it and did do OK...but still, I know when blood is coming out of a turnip. |
The fact that you still stand by the mantra that "if it works it must be OK" tells me something about you
(I decided I don't need insulation on my power cables anymore, by the way.)
| Quote: |
Sooo....I do have a Macro 5002. I am likely going to put that on the subs and see if that beefs up the low end while running that in Stereo so I got 2 boxes a channel. I think the Damping Factor alone will tighten up the low end but I know I need more subs and amps. That is a given. |
There is no question the Macro 5000 is going to destroy your extremely improperly deployed, tiny amps.
| Quote: |
Now, for the DSP. The DSP actually controls the Limiter settings for the MPX1200 amps, so TECHNICALLY it does control the Sub output. If your processor isn't letting out the voltage, the amp can't do anything. P=IV...No V...No power. Not being sarcastic, just I went to college for Electrical Engineering and still remember a few things. |
Ignoring improperly set limiters, the DSP has nothing to do with maximum output.
| Quote: |
I really do appreciate both of your guys input. Me being one not living in the world of Tekno Music definitely has opened my eyes in the lows of lows. I wish I had a couple of Servo-Drive woofers and say ...take that you Baby Bottle Glow Stick Waving Kiddos! LOL...What is actually really funny is that at the last show, about half of the Kids dancing around all had EAR PLUGS in...then they keep telling me to turn it up...Ummm...something doesn't seem right here. Some of us Old Farts doing sound, yes I am 38, think if its too loud, turn it down. Ahh well. Any more input or comments are appreciated..Thanks again, take care my friends... |
If they wanted it turned up at a dance, they probably wanted to feel more bass. The associated increase of highs from a rock system was probably unpleasant, hence the earplugs (that don't block bass). So next time you might try to turn up your sub bandpass, and re-align the system with the new acoustic crossover. If you can.
Post by: Elliot Thompson on December 01, 2010, 04:09:00 PM
The JBL MPX 1200 is a re-badge QSC EX 4000 which was manufactured in 1987.
This amplifier was considered very powerful nearly 20 years ago and performs well on the 4719 providing it is seeing a 4 ohm load in stereo mode (600 watts each woofer)
You’ve mentioned twice that you are bridging this amplifier and loading a pair of 4719s under bridge mono configuration. This equates to a 2-ohm load on an amplifier rated @ 4-ohm bridged mono minimum load.
By attaching more speakers below the amplifier’s minimum impedance load you not only overheat the amplifier faster, but also attain less watts. So you are making matters worse.
Your problem can only be resolved if you use more subwoofers. There is really no other way to get around it. With two MPX 1200s and four 4719s I would suggest loading one bin on each channel in stereo mode. That should be around 4800 watts total. That is not a lot for dance music but at least you are feeding each driver 600 watts (which is the recommended wattage on the 2241 woofer) and not overloading the amplifiers during the process.
Best Regards,
Post by: Jim Schneider on December 01, 2010, 04:52:16 PM
@ Silas: So are you saying that if you have 0 (Zero) Voltage going into an amp, there is power coming out of the amp? As for the Square wave babble...I should of been more correct and said distortion from clipping...Marketing? Of Course! Doesn't everybody buy something from what a birth certificate or manual says? I have never used these amps before, my buddy got them on a package deal...stupid me, believing that JBL would sell a JBL Amp that would work with their Speakers...heh...As for judging me on my "its ok" thing...come on buddy. You gonna tell me that you haven't used a piece of gear in a way that you know really wasn't supposed to be used in the application you are wanting it to be in? hehehe....I have put 8 sb1000s on a Macrotech 5002. Put a Big Fan on it and it worked 'OK'....Yes, I know I was killing it, but I am one of those types that like to do the REAL world stress test on Sound Equipment. How else will people that use gear know REALLY what something will do. Call me Crazy. I love your comment "improperly deployed"...Can I use that? Its awesome. Finally to the Ear Plugs thing...No, the Highs were not killing anybody...the kids were all standing in front of the stage where the subs were in between the tops...so all they were getting was low-end and a very comfortable level of stage fills for the DJ...Again, I appeciate your output buddy...its not often people can be honest and talk about stuff without someone get butthurt. Good times...
@Elliot: Thanks again for Chiming in, I do appreciate your input. As for the amps running 2 ohm mono, yeah...I am sure they are screaming at me...I will go ahead and try running the amps stereo and see if I get anything more out of them...I know I should just use the Macro 5k and call it done in Stereo...I am just trying to appease my friend who wants to squeeze every ounce of power out of this PA...
My Real World Idea for this dilemma would be to just have 6 Meyer HP700's and 2 Servo Drive 12" and call it done...to Dream. ahhhh.
As for both of yaz...I will let ya know how things go hopefully tomorrow after the DJ gig AGAIN tonite...
-Jim
Post by: Silas Pradetto on December 01, 2010, 05:05:39 PM
No, I'm just saying that efficiency of an amplifier can never reach 100%, so the output power will never exceed the input power. Output voltage can certainly exceed input voltage, of course at lower current.
And good luck at your gig, avoid boundary cancellations and lighting amps on fire!
Good luck!
PS--if you used 700HPs and a horn sub at the same time, it would require very careful stacking and phase alignment. Not to mention, no one uses servodrive stuff anymore. You're old school!
Post by: Jim Schneider on December 01, 2010, 05:31:55 PM
Very True...Just wish in todays audio world we could truly have an amp that is 80% efficient....heh.
As for the Servo! Heck yeah I am old School!!!
As for the fire...My Old School mentality makes sure I always bring a fire Extinguisher...don't worry...I use the new stuff...not the old pump handle water spickets...lol...Thanks again.
-Jim
Post by: Brendan Maroney on December 02, 2010, 01:06:15 PM
Brendan
Post by: Jim Schneider on December 02, 2010, 01:40:45 PM
You are correct...No 2ohm MONO Bridged Rating...
Post by: Todd Anisman on December 08, 2010, 05:40:11 PM
Post by: Jim Schneider on December 08, 2010, 06:17:26 PM
Post by: sheldon harris on December 12, 2010, 04:41:26 PM
you might want to invest in a speaker management processor in the future. one that can set hi pass for the subs and with different limiting features for "DJ work" (or get a dominator 2)
most of the labsters had it out of the gate that you needed more rig. i do know you are very lucky to have those mpx still working properly: they over heat, cycle in and out and drop op devices when loaded down that low with continuous sub-low content like dubstep .
Post by: Jeff Wheeler on December 14, 2010, 08:35:39 PM
| Jim Schneider wrote on Wed, 08 December 2010 17:17 |
However, we are likely only going to do bands for the majority of work now. The DJ thing just wasn't worth the hassle. |
It can be if you understand the needs of modern DJs, and treat them like customers with money to spend. And, as always, screen out the cheapskates, which is the case with every kind of customer, whether they play guitars or vinyl.
You can make money off DJs, but the statement below reads more like someone who has a sound "hobby" than a "business." If that is the case, by all means, turn away gigs that you do not enjoy!
| Jim Schneider wrote on Tue, 30 November 2010 18:20 |
I was told by a few people I needed more low end...the DJ was playing a lot of this Dubstep stuff amongst other names I never heard of or care,mainly cuz I am a live BAND guy. |