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Author Topic: Turbosound Floodlight SMAART measurements  (Read 6629 times)

Peter Hvedstrup

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Turbosound Floodlight SMAART measurements
« on: February 27, 2015, 06:47:10 am »

Hi all

I recently did a gig where my Floodlight system was measured using SMAART. The qualified guy who measured it said he didn't understand the graphs of my system, but he did think it sounded good even compared to his own Meyer rigs.

He especially talked abut the phase between tops and subs not looking correct but without being able to tell me what to do. 

The speakers measured is one TFL-760Ht top and one TSW-718 sub. The system is 4-way and controlled by Turbosound LMS-D24 (rebadged Linea Research) with the default Turbosound settings.

   Gain   Polarity Delay   HP            LP
2x18"    +2   +      0,000   15Hz *   180Hz
12"     0   +      3,875   180Hz   1.31kHz
6.5"     0   +      3,875   1.31kHz   8kHz
1"     0   -      3,906   8kHz           22kHz

I have attached phase plots for various measurents. Can anybody tell me if it looks ok?



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Brian Bolly

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Re: Turbosound Floodlight SMAART measurements
« Reply #1 on: February 27, 2015, 06:44:55 pm »

He especially talked abut the phase between tops and subs not looking correct but without being able to tell me what to do.  I have attached phase plots for various measurents. Can anybody tell me if it looks ok?

No, it doesn't, and the results are in the first two screen shots.  Here's why:

Look at the first set of traces here:



Look at the frequency response at the acoustical crossover point between the sub and the top - right around 210 Hz.  Now look at the phase response of each box at that point - the phase response is offset.  You can see it better if you roll the phase trace plot so it goes from 0-360 instead of +/- 180.  Looks like the boxes are roughly 90 degrees out of phase at this point, give or take.


Now look at the summed trace of all boxes:



There's a frequency response dip at that point.  If the boxes were in phase with each other, they would sum - at least continuing the trend of the frequency response slope.  But, we already know they were not by looking at the individual phase plots of the top vs the sub.

This can all be fixed by applying some delay to the sub.  There is 0ms of delay in the preset because Turbo likely assumed (way back when these presets were all written) that this could be adjusted in the field.  If the phase traces line up at the acoustical crossover point, the boxes will sum and produce a better frequency response.
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Timo Beckman

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Re: Turbosound Floodlight SMAART measurements
« Reply #2 on: February 28, 2015, 01:00:43 pm »

What kind of filters and filter order are used in the processing?
Was there a lot of distance between the tops and subs (tops stacked or flown?).
Also how many subs where used?

if i take a really wild guess : try 1.3 - 1.5ish ms delay on the sub and polarity reversal () might do the trick but this is a WILD GUESS !!!!!
Also can you post screenshots with the coherence active please?
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Peter Hvedstrup

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Re: Turbosound Floodlight SMAART measurements
« Reply #3 on: March 03, 2015, 04:40:27 am »

What kind of filters and filter order are used in the processing?
Was there a lot of distance between the tops and subs (tops stacked or flown?).
Also how many subs where used?

if i take a really wild guess : try 1.3 - 1.5ish ms delay on the sub and polarity reversal () might do the trick but this is a WILD GUESS !!!!!
Also can you post screenshots with the coherence active please?

Hi

Thanks for your replies.

The filters used are 16db BW hi pass on the sub and the rest is 24db LR.

The only thing changed in my settings from the Turbosound ones is hi-passing the sub at 30hz instead of the suggested 15hz. Could this influence the phase between sub and top?   
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Hayden J. Nebus

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Re: Turbosound Floodlight SMAART measurements
« Reply #4 on: March 03, 2015, 11:08:14 am »

Hi

Thanks for your replies.

The filters used are 16db BW hi pass on the sub and the rest is 24db LR.

The only thing changed in my settings from the Turbosound ones is hi-passing the sub at 30hz instead of the suggested 15hz. Could this influence the phase between sub and top?

The phase response of the 30HZ subwoofer HPF will largely be flat at frequencies within its passband. There is some deviation from flat phase above the 30Hz corner frequency, but this approaches zero at increasing frequency long before you reach the xover to the mains.

 

Generally speaking,
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Eric Vogel

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Re: Turbosound Floodlight SMAART measurements
« Reply #5 on: March 03, 2015, 12:35:30 pm »

Hi

Thanks for your replies.

The filters used are 16db BW hi pass on the sub and the rest is 24db LR.

The only thing changed in my settings from the Turbosound ones is hi-passing the sub at 30hz instead of the suggested 15hz. Could this influence the phase between sub and top?

Have a look here:

http://www.linea-research.co.uk/documents/HighPassFilters%20White%20Paper%20-%20C.pdf

http://www.linea-research.co.uk/documents/CrossoverFilters%20White%20Paper%20-%20B.pdf
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ProSoundWeb Community

Re: Turbosound Floodlight SMAART measurements
« Reply #5 on: March 03, 2015, 12:35:30 pm »


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