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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => DJ Forum => Topic started by: Dennis Wiggins on October 21, 2019, 05:22:21 PM
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Has anyone had any bad experiences (reliability, early limiting (pumping), intermittent shutting down) with the Behringer NX4-6000? The online reviews are very scarce.
I am only needing 400-500 WRMS @ 8Ohms x 4. All channels will be high-passed BW24 @35Hz, or higher, and will never be running 2 Ohm loads.
It would only be used 3-4 times per year, so I am not willing to make a higher investment as I am accomplishing the same thing now with a pair of original (silver) IPR3000s. They are just right for my purposes.
I would just want to "shrink the rig" a bit.
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That amp only puts out ~48 volts continuous / channel so about 276 w into 8 ohms which is about 2 dB's lower than you had hoped for. The IPR3000's are closer to 58 volts / channel continuous.
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I have 3, bought from a forum member.
The 48v is a hard limit. It has no oomph beyond 48v.
That said... bridge a pair and it does quite well into an 18" sub.
No issues with the amps so far, all measure very well.
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That amp only puts out ~48 volts continuous / channel
Hmm... In reality then, I can probably expect about 250@8, 500@4, and about 1000@2. That's a long way from 6000(!), but may do for lower volume (dinner music and talking-head) gigs.
My socks are still on, and my head has no room. ;)
There will typically be 4 Sb122s (2/channel) and 2-Sx300s (1/channel).
I also do a lot of mix and match with Peavey Impulse100/1012, DXR10/12 and EV ZXa1-Sub, EV ZXa1 and ZX1 cabs. This is just another tool.
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...The 48v is a hard limit. It has no oomph beyond 48v...
Does it, at least, limit gracefully, or does it "pump"?
As you you can tell, I'm a bit wary... I am comfortable with the the "feel" * of the IPR 3000s, but would probably find the NX4 a bit "squishy."
* I am a DJ, and hitting the limiters is what I listen for - been doin' it since '78 - I ain't gonna change.
It's kind of like when you twist the grip and hit the power band. You let up.
Unless you don't. That's when the limiters save you ;D
(Specifically, I have my VXS26s set to 'knee' at the same level that DDT would kick in on the IPRs. It's pretty idiot-proof; the idiot being me.)
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I would just want to "shrink the rig" a bit.
Going from two IPR3000's to one nx4-6000 saves you a whopping 1.6 lbs! I think you've reached the point of diminishing returns.
DDT circuitry is about as graceful as a limiter as you are going to get built into an amplifier. There is no knee on the nx4-6000, it just flatlines at 48 volts, however you could set up your DSP to ease into your desired limit.
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Going from two IPR3000's to one nx4-6000 saves you a whopping 1.6 lbs! I think you've reached the point of diminishing returns.
DDT circuitry is about as graceful as a limiter as you are going to get built into an amplifier. There is no knee on the nx4-6000, it just flatlines at 48 volts, however you could set up your DSP to ease into your desired limit.
That finishes it off, as it coincides with what Nathan also said about about how it acts when "hitting the rail".
Thanks to All. End of story.
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I have 3, bought from a forum member.
The 48v is a hard limit. It has no oomph beyond 48v.
That said... bridge a pair and it does quite well into an 18" sub.
No issues with the amps so far, all measure very well.
Nathan,
The NX4-6000 are a fairly recent addition to the Behringer line, notice any differences between them and the three NU4-6000 I sold you?
Art
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Going from two IPR3000's to one nx4-6000 saves you a whopping 1.6 lbs! I think you've reached the point of diminishing returns.
... and halved your rack size.
I have a couple of NX4-6000s. One ran monitors (replaced with a Powersoft T304) and the other lived with a DCX2496 for smaller events. Both did fine. The monitor amp had an easy life at 8ohm/ch, but the one being used for smaller events would often run with Ch1 & 2 driving 8ohm/ch, and then Ch3/4 bridged into a pair of subs.
Both have always done the job for me, and never sounded bad. The Powersoft T-series sounds better, but with that price difference it's to be expected.
Chris
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Nathan,
The NX4-6000 are a fairly recent addition to the Behringer line, notice any differences between them and the three NU4-6000 I sold you?
Art
Awe man, you nicely told me I was wrong! What a great guy!
I have 3, bought from a forum member.
The 48v is a hard limit. It has no oomph beyond 48v.
That said... bridge a pair and it does quite well into an 18" sub.
No issues with the amps so far, all measure very well.
So yeah, Dennis, what I posted was about the older model NU4 NOT the new NX4 you asked about.
Sorry. Thanks Art.
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Awe man, you nicely told me I was wrong! What a great guy!
So yeah, Dennis, what I posted was about the older model NU4 NOT the new NX4 you asked about.
Sorry. Thanks Art.
Perhaps the same could be said for Chris' response ;^).
Other than cosmetic changes, the NX4-6000 appears pretty much the same spec wise to the NU4-6000. From what I have measured the NU4-6000 actually reduces level slightly (about 1 dB) when it's clip/limit light illuminates.
It would be informative to see a side by side comparison to determine if there are any audible or measurable differences between the two models, though for the OP, for a few gigs a year, can't see any benefit to make a change.
That said, I wouldn't be looking to trade my NU4-6000s for IPR3000s ;^).
Art
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I've still got an NU4-6000 sitting around here, and have some measurement gear.
What do you wanna see?
I've got REW, but no load bank. I do have a bunch of 1KW subwoofers, though, which can act as a very noisy load bank.
From what I've seen online, the main difference is that the NX series takes the output feedback post-filter, so there shouldn't be any variance in HF response with load. Should be pretty easy to test that.
These amps, IMO, represent the peak of the price-to-performance curve. They're not the best amps in the world, but you have to drop quite a lot more cash before you get worthwhile improvement.
Chris
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I've still got an NU4-6000 sitting around here, and have some measurement gear.
I've got REW, but no load bank.
What do you wanna see?
Chris,
Cheap load bank- baling wire wrapped around a brick. Used space heaters before, but the bricks were a lot easier, and a lot less noisy than speakers ;^).
I still have two NU4-6000, but have never tested the NX4-6000.
A few days ago you mentioned you have a couple of NX4-6000s.
I'd like to see if the NX4-6000 limiters respond the same as the NU4-6000 limiters, and if there is any difference in the different amplifiers output voltage at onset of limiting.
Cheers,
Art
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Hi Art,
Sounds easy enough. I've got Dad's old 'scope here - if it still works I'll try to get some photos of the clipping/limiting waveform.
I've got 1x NU4-6000 and 2x NX4-6000, so it'd be easy enough to do some comparisons.
The digital mixing desk I use lets me increment the output level in 1dB steps, so I could do steady-state output voltage over a 9dB range, going from -3dB to 6dB into limiting.
Chris
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Chris,
Looking forward to the results!
Good luck with the amp sales.
Art
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Chris,
Cheap load bank- baling wire wrapped around a brick. Used space heaters before, but the bricks were a lot easier, and a lot less noisy than speakers ;^).
I have used an electric kettle (with water in it) and the bonus is a cup of tea when testing is done :D
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...the NU4-6000 actually reduces level slightly (about 1 dB) when it's clip/limit light illuminates.
It becoming clear that my fear that the NX would "sonically cavitate" when it hits its limiters is unfounded. I'm about 99+% ready to purchase when the calendar flips on Jan 1st, unless Santa... ;)
Update: I ordered one. I'll be setting limit/knee in my DSP.
-Dennis
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Just a quick note to say that I haven't forgotten about the testing, it's just that life has a habit of getting in the way of playing with sound equipment.
Hopefully I'll have something on Friday. If not, next week.
Chris
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...life has a habit of getting in the way of playing with sound equipment.
I received it and made sure it powered up, but had to let it sit until the upcoming weekend. I will be doing my usual un-scientific and hopefully, non-destructive, testing and will report back.
+8degF tends to put a damper on real-life testing outdoors. ;)
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Got the amps and the scope out. After some rummaging to find the probes, and letting the scope warm up for a while, the results are in.
I put a pair of Faital Pro 18XL1800 in parallel on CH1 of each amplifier, set up a test frequency (36Hz, because it showed up on the scope pretty well and is a reasonable distance from Fs) and let them rip.
The amps are identical under overload conditions.
Both amps do the following:
- As you ramp up the levels (I was doing 1dB steps), the first cycle would clip (this was audible) and then the level was cut back so that the sine tone was being reproduced without clipping. You could carry on pushing the level up, and keep getting the same results. I went 10dB into clip and found the same results.
- Left to their own devices, the level seems to stay constant for at least 10 seconds.
Hope that's useful. I couldn't measure the exact voltage output as it was more than the scope could display. It was, however, enough to get those 18" cones really moving (albeit in free-air).
Chris
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Chris,
Thanks for the test!
For what it's worth, when testing the NU4-6000 with two bridged mono pairs each driving four ohm loads just below the illumination of the clip/limit light each put out 85.5 volts at 60 Hz. The mains voltage on a 100' 10AWG 120V line dropped from 118.1 volts down to 107.2 volts, drawing 31 amperes. If the power supply was a full 120 volts, output would probably be around 96 volts bridged mono.
Using just one bridged mono pair, the amp ran for 40+ seconds before I terminated the test, as the amp was drawing 19.8 amperes, and the "tired" 20 amp mains breaker had popped several times in various tests already.
Art
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...I went 10dB into clip and found the same results.
- Left to their own devices, the level seems to stay constant for at least 10 seconds.
I did plenty of "no load" testing to determine structure. I trimmed pink noise to be at Unity at main outs and on the channel strip. I typically run program between -20 and -10 w/extreme peaks at 0. This is the max I design for, leaving plenty of room for "screw-ups." The VSX is set to start limiting at +9, 2.5:1.
The self-noise (a slight, noticeable "hiss") of the VSX26, which outputs directly to the amp channels, triggers the NX4's "signal" LED right at "3 O'clock." This is normal (edit: for a VSX). I backed off one click.
I always back off the amp inputs to "noon" at the beginning of a show and advance, as necessary, as the gig progresses. This is specifically why I needed 4 amp channel controls at my fingertips. I like my mixer to be the same all the way through a show.
With the output I am hearing (albeit, indoors), I doubt that I'll get near the B's limiters, except when I add Kosmos effect which will easily cause the sub channels to hit the B's limits (it does the same with the IPR3000). As always a little of that goes a long way.
It's raining. Bummer. I want to crank it up all the way.
Thanks to All!
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The self-noise (a slight, noticeable "hiss") of the VSX26, which outputs directly to the amp channels, triggers the NX4's "signal" LED right at "3 O'clock." This is normal. I backed off one click.
Dennis,
The change in meter ballistics between the NU4 and NX4 is funny, Behringer got it wrong on both-
NU4 uses -24, 12,-6, limit, the NX4 is -40, -6, -3, limit. Who cares about -40 dB, less than 1/10th of a watt at 4 ohms?
That said, I still wouldn't consider a 40 dB signal to noise ratio "normal" for this century, but we all get used to different stuff ;).
Art
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Yeah, the NX series effectively have meters that jump from "I'm doing almost nothing" to "I'm in the last few dB of headroom". Nothing in-between.
The NU series got the LEDs better in that regard.
Chris
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...the NX4 is -40, -6, -3, limit. Who cares about -40 dB, less than 1/10th of a watt at 4 ohms?
For Ceremony to Dinner Music to Dance Hall -40 to -6 is exactly the "guard rails" I run between on my mixer. Pure dumb luck, I guess.
-D