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Author Topic: Nexo S118 and frequency response  (Read 802 times)

Miguel Dahl

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Nexo S118 and frequency response
« on: February 01, 2018, 03:10:47 pm »

Hi.

The company I work for is looking for a new small-sized line array. We've had the Nexo STM M28 on demo for two shows we've done with the S118 subs.

For the first show we stacked three of them on top of each other on each side. The FOH-guy ended up just swapping them for 1x RCF 9007 pretty early in the rehearsals.

Second and different show I was doing FOH, and got some time with them. But this time they were two stacked pr side on the stage, and two used as fills.

Anyhow. "All" I'm getting is two spikes from them, 63-65 Hz, and one further up. Me and the guy doing FOH the first show agreed that if you listen to a bass line that is supposed to be smooth and musical, you get that B1-note/C2 everywhere. It's just dominates. We were powering the subs with NX4x4 amps, one amp powering both sides, two channels bridged into each stack. And when listening to some music, some of the lower notes just weren't there, which is audible on some other systems. It stops dead, pretty hard rolloff?

When we turned down the 63 on a graphical, to get some more balance in the music, the sub almost went mute. My thought was that "allright, then we need to buy more subs"..

Anyone here has some tips or tricks to this sub? We have an offer to buy 12x M28 and 6x S118. But to make it sound at least a bit more musical, meaning turning down that one dominating frequency range, I guess more subs are needed to still get the required output, which costs money. For both shows the system was set up by a rep.

Any input is highly appreciated.
« Last Edit: February 01, 2018, 03:43:56 pm by Miguel Dahl »
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Ivan Beaver

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Re: Nexo S118 and frequency response
« Reply #1 on: February 01, 2018, 08:03:31 pm »

I would start with 2 things.

I have run into many cases in which something didn't seem right.

In all cases there was a "hidden" setting somewhere in the digital console or DSP or amplifier.

Sometimes it has been a limiter, or a high pass filter or an inserted EQ.

First measure the existing sub kinda close.   A meter or so.  A simple RTA app will work for this rough test.

Next, without changing the amp or any other settings, hook a different sub to the same amp channel, and measure again.

If the same thing exists, then it could be a weird setting somewhere. 

Measuring is much better than guessing and you should only change ONE THING at a time.  If you don't, then you don't what the actual problem is.
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Chris Grimshaw

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Re: Nexo S118 and frequency response
« Reply #2 on: February 02, 2018, 03:42:50 am »

Any chance of phase/polarity issues in the setup?
Bridging an amp means half the signal output is polarity-reversed, and careful wiring is needed to make use of that.

Chris
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Peter Morris

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Re: Nexo S118 and frequency response
« Reply #3 on: February 02, 2018, 06:54:12 am »

Hi.

The company I work for is looking for a new small-sized line array. We've had the Nexo STM M28 on demo for two shows we've done with the S118 subs.

For the first show we stacked three of them on top of each other on each side. The FOH-guy ended up just swapping them for 1x RCF 9007 pretty early in the rehearsals.

Second and different show I was doing FOH, and got some time with them. But this time they were two stacked pr side on the stage, and two used as fills.

Anyhow. "All" I'm getting is two spikes from them, 63-65 Hz, and one further up. Me and the guy doing FOH the first show agreed that if you listen to a bass line that is supposed to be smooth and musical, you get that B1-note/C2 everywhere. It's just dominates. We were powering the subs with NX4x4 amps, one amp powering both sides, two channels bridged into each stack. And when listening to some music, some of the lower notes just weren't there, which is audible on some other systems. It stops dead, pretty hard rolloff?

When we turned down the 63 on a graphical, to get some more balance in the music, the sub almost went mute. My thought was that "allright, then we need to buy more subs"..

Anyone here has some tips or tricks to this sub? We have an offer to buy 12x M28 and 6x S118. But to make it sound at least a bit more musical, meaning turning down that one dominating frequency range, I guess more subs are needed to still get the required output, which costs money. For both shows the system was set up by a rep.

Any input is highly appreciated.

These are the specs for the S118

Frequency Response    27Hz 85Hz 3dB
Usable Range @-6dB    23Hz 100Hz
Sensitivity 1W @ 1m    109dB SPL Nominal
Nominal Peak SPL @ 1m 143dB Peak
Nominal Impedance   16Ω (12 Ω min)
Amplified Controller   NXAMP4x4 - 3xSTM S118 in parallel on 2 NXAMP4x4 bridged channels - 8000W/4Ω


These are a bit crazy for a single 18" unless there was some kind of resonant peak use to achieve the 109dB efficiency ... I assume that's a half-space measurement.

It looks like a 6th order band pass and I suspect you have not applied the correction EQ.

Here is a guess at something like (not exact just for expatiation) whats happening - yellow raw output, purple EQ-ed output (1 x PEQ @ 75 Hz).

FWIW when I have heard the S118 they sounded fine.
« Last Edit: February 02, 2018, 06:59:14 am by Peter Morris »
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Mike Eiseman

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Re: Nexo S118 and frequency response
« Reply #4 on: February 02, 2018, 11:30:17 am »

Miguel - can you tell us where your crossover settings are for:

the S118's (60Hz, 85Hz, or 120Hz)
the M28's (60Hz, 85Hz, 120Hz, or 180Hz)

also - are you using any Array EQ on the M28's?
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Miguel Dahl

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Re: Nexo S118 and frequency response
« Reply #5 on: February 06, 2018, 11:30:44 am »

Miguel - can you tell us where your crossover settings are for:

the S118's (60Hz, 85Hz, or 120Hz)
the M28's (60Hz, 85Hz, 120Hz, or 180Hz)

also - are you using any Array EQ on the M28's?

they were at 85/85

However. Just came back from a session where we hung the same rig, in a different room where we've been doing tests on other systems, and the subs sounded better, but still "spike-y". Went through all settings on the amps and there wasn't anything that was tampered with. I forgot some cables for my soundcard at home so I wasn't able to measure it properly.

However. Probably got some bad coherence, but what I was able to see were some lobes, and also hear it, but not as drastically as in the first two rooms. I did a sweep with a sine and just by ear I still had a bump in the 63hz. We also hung one side of a Coda ViRay and hooked up the subs to that system and one could really tell a difference. The distance to the back wall was about 10 meters.
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Miguel Dahl

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Re: Nexo S118 and frequency response
« Reply #6 on: February 14, 2018, 02:58:54 pm »

I guess I'm talking to myself. But for what it's worth. I love the system, even though the boxes are heavy as stone and aren't very stack-friendly in that manner. I know they are suppsed to be flown, but still, The M28 is not a big box but it sounds great.

Anyhow. Did another job where I stacked them, and boy does it take a lot to make the subs sound "flat", or musical.

does anyone have the same experience? I feel that I'm the one doing something wrong here, but I've checked everything, several times, and to me the subs aren't very musical without some job.
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Tim McCulloch

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Re: Nexo S118 and frequency response
« Reply #7 on: February 14, 2018, 09:22:15 pm »

I guess I'm talking to myself. But for what it's worth. I love the system, even though the boxes are heavy as stone and aren't very stack-friendly in that manner. I know they are suppsed to be flown, but still, The M28 is not a big box but it sounds great.

Anyhow. Did another job where I stacked them, and boy does it take a lot to make the subs sound "flat", or musical.

does anyone have the same experience? I feel that I'm the one doing something wrong here, but I've checked everything, several times, and to me the subs aren't very musical without some job.

It's a bandpass design which is much louder at 1 or 2 frequencies than the remainder of the operating bandwidth.

Perhaps you'd get more response directly from Yamaha/Nexo?
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Chris Grimshaw

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Re: Nexo S118 and frequency response
« Reply #8 on: February 15, 2018, 03:53:35 am »

It's a bandpass design which is much louder at 1 or 2 frequencies than the remainder of the operating bandwidth.


Only the badly designed ones.

I suspect something's askew, like a driver not being bolted down tightly.

Chris
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