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SOUNDSYSTEM SOUND-OFF - Event Date: 05 January 2014

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levyte357- View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:08am
Originally posted by csg csg wrote:

Whats the deal with Mains here - are we allowed to tail in? will have a qualified sparks with me, ideally a 63A single or 3 phase if we all want a bit extra. Anyone know what the incomer is good for?

If thats not allowed i guess we can daisychain through a couple of PD7-32's as we wont be playing and drawing current at the same time, i will struggle on 1 32A as my gear is not efficient like you scoop boys.


How many subs are you bringing, though it was a 4x sub gig !? Shocked

When Shabach went in there, we ran just 4x scoops, off 1x 32A supply, rattled the place to bits with smooth sub, and "apparently" smashed 30-40x glasses in the kitchen.


Global Depopulation - Alive and Killing.
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TONY.A.S.S. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TONY.A.S.S. Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:25am
You sure that wasn't the Turk throwing stuff around in the kitchen because he could no longer stand the noiseLOL
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Post Options Post Options   Thanks (0) Thanks(0)   Quote peter_p Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:26am
Must have been the high levels of 3rd order harmonic distortion from the scoops that set up a sympathetic resonance in the glasses.

No way could that be down to pure bass pressure.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote peter_p Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:27am
Do they also have a 'Nick the Greek, in that place.
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TONY.A.S.S. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TONY.A.S.S. Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:30am
I don't think that would be a very good mix.
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levyte357- View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:54am
Originally posted by peter_p peter_p wrote:

Must have been the high levels of 3rd order harmonic distortion from the scoops that set up a sympathetic resonance in the glasses.

No way could that be down to pure bass pressure.


Always plenty of people here, with armchair opinions.

Move from comp, and come to Golden Palace sometime.. Then your opinion will be relevant. LOL
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peter_p View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote peter_p Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 1:58am

Seeing as you're around Tony, what's your take on the scoops and distortion debate.

I think the problem is further up the chain and not the scoop itself.

The first harmonic is the fundamental and contains no distortion. 2nd order harmonics are considered even harmonics , with the second multiple being most prominent. 3rd order harmonics are considered odd harmonics, with the third multiple being most prominent.

A pure sine wave contains no harmonics other than the fundamental, a pure square wave produces only odd harmonics and a pure sawtooth wave produces both even and odd harmonics.

Scoop are said to produce a warm and fuzzy kind of sound, which would indicate that they are high in 2nd order 'even'  harmonics. But I'm not so sure. To me when a scoop is driven to very high levels the sound takes on a hard edge, which is more indicative of 3rd order harmonics. And if that's the case then I would surmise that it's the amp going into clip and producing a square wave, which would be high in 3rd order 'odd' harmonics.   

So is it the scoop itself that's producing distortion, or an overdriven amp that is squaring off that's to blame.

One other fact worth noting is the difference between transistor output stages and valve output stages. Many think that valves only produce even harmonics and that transistors only produce odd harmonics. This is not true as both types of output stages produce both even and odd harmonics. It's just the ratio of harmonics produced by both types that sway it one way or the other.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote peter_p Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 2:01am
Originally posted by levyte357- levyte357- wrote:

Originally posted by peter_p peter_p wrote:

Must have been the high levels of 3rd order harmonic distortion from the scoops that set up a sympathetic resonance in the glasses.

No way could that be down to pure bass pressure.


Always plenty of people here, with armchair opinions.

Move from comp, and come to Golden Palace sometime.. Then your opinion will be relevant. LOL


You need more mulled wine to see the humor in my post Ray.
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levyte357- View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote levyte357- Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 2:13am
Originally posted by peter_p peter_p wrote:

Originally posted by levyte357- levyte357- wrote:

Originally posted by peter_p peter_p wrote:

Must have been the high levels of 3rd order harmonic distortion from the scoops that set up a sympathetic resonance in the glasses.

No way could that be down to pure bass pressure.


Always plenty of people here, with armchair opinions.

Move from comp, and come to Golden Palace sometime.. Then your opinion will be relevant. LOL


You need more mulled wine to see the humor in my post Ray.


You're right.. Good to see you about.. ClapLOL
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Heathrow_B_line View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heathrow_B_line Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 2:19am

when you need to blow the bloody doors off, bring the full scoops!

 
if you want the science bit go watch a pentene commercial
 
lol
 
 
 
 
 
 
Produce a killer sound. Take no prisoners.
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peter_p View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote peter_p Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 2:52am
Ok that's it.

In the new year I will do full lumped parameter analysis to the following specs:

Nonlinear system excited by a two-tone stimulus u(t)= 1.4U0 sin(2πf1t)+1.4U0sin(2πf2t) with the first excitation tone at frequency f1 and a second tone at f2, generating a state variable p(t)) subjected to a spectral analysis (Fourier transform FT) giving the spectrum (e.g P(jω)=FT{p(t)}).

As, traditional harmonic distortion measurements only exploit the amplitude of the harmonic components. The phase of the higher-order harmonics is usually neglected because the interpretation is difficult. However, both phase and amplitude spectrum determine the waveform of the distortion in the time domain. The waveform of the harmonic distortion signal can be calculated for a sinusoidal stimulus at ω by applying the inverse Fourier transform to the harmonics in the complex spectrum giving the Instantaneous Harmonic Distortion in percent.

 

I will also analyze for wave steepening where at high amplitudes a sound wave propagates at the maxima faster than at the minima causing a gradual steepening of the wave front. This mechanism is found in horn loaded drivers. The nonlinear mechanism is basically a multiplication of the sound pressure with the differentiated sound pressure in each section of the horn.

And also for throat non-linearity, which is the generation of turbulence's in the air flow that behave as sound sources causing broad band noise in the output signal.

I'll measure a scoop, a front loaded horn and a reflex box, all using the same driver to eliminate possible variances in dc-displacement state variables and asymmetrical nonlinearities Kms(x) and Bl(x)

The biggest question with this analysis is, steve b, .44, RX18 or ligwa. And should we carry out all measurements in hanger lane.

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csg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 26 December 2013 at 8:34am
Originally posted by levyte357- levyte357- wrote:

Originally posted by csg csg wrote:

Whats the deal with Mains here - are we allowed to tail in? will have a qualified sparks with me, ideally a 63A single or 3 phase if we all want a bit extra. Anyone know what the incomer is good for?

If thats not allowed i guess we can daisychain through a couple of PD7-32's as we wont be playing and drawing current at the same time, i will struggle on 1 32A as my gear is not efficient like you scoop boys.


How many subs are you bringing, though it was a 4x sub gig !? Shocked

When Shabach went in there, we ran just 4x scoops, off 1x 32A supply, rattled the place to bits with smooth sub, and "apparently" smashed 30-40x glasses in the kitchen.



I dont need 63/3 Ray, the idea if we are tailing in is that everyone can have some more mains, it can all come from the same panel so we can spread it over the 3 phases instead of sticking a single 63A in, and hanging it all of one - which is far from ideal.

Whether we will tail in remains to be seen, depending on how solid the supply is and if it is safe to do so. If not, i will need to find a second 32A as ill be using 2 racks, and each will need a 32A.

sub wise - please remember my little reflex subs are a very different beast to a scoop, mini or otherwise.

Maximum SPL with minimum drivers is not a prime concern of mine, we use larger numbers of drivers / subs for 2 reasons

1) sound quality 

2) perceived throw outdoors and pattern control ( bass steering, cardioid arrays) where more sources gives you greater control

the size of my stack will be smaller than most others, certainly that of a 4 x full scoop stack, and i dont use mid bass boxes - subs go straight into mid highs. 

we will use 8 subs as subs only, with 4 more running slightly higher, then will have a stack of 6 arcline 6 on top, with a few of my mini mid highs around for ambience.
“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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