Eq-ing FOH |
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Foca_Dacian
Registered User Joined: 05 February 2011 Location: Romania,Cluj Status: Offline Points: 118 |
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Posted: 24 September 2017 at 5:58pm |
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What type of an eq curve is needed for a good sound?
I have flattened a sound system I use for live sound with an RTA mic and pink noise,but it did not sound good.There was a lack of low frequencies, and also it sounded harsh in the high frequencies. I have to mention I am new in the live sound bussines , did not go ta any specialised school and certain things I need to learn along the way and at the moment I do live sound for small bands in small indoor gigs. Does RTA measurement take in account the Fletcher and Munson curves and it's linearity is based on that? If not,after RTA is done and the system is flat ,I should substract and add frequencies acording to the spl of the system and the way I percieve the sound at that level ? I would apreciate some material or some links to read and better understand the steps I have to take to obtain a good sounding FOH.
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jacethebase
Old Croc Joined: 23 September 2009 Location: Somerset Status: Offline Points: 5697 |
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Do you own the Yamaha Sound Handbook?
How are you using your RTA? How do you have it setup? |
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www.wedding-production.co.uk
www.stage2sound.com |
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10920 |
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You tune the system ‘flat’ and then tone it to taste for he mixing engineer. I prefer a flat start point and to add tone via channel strip and mixing personally but not all do. Likewise the tone will vary depending on the overall SPL you expect to run at. So the answer to your question is ‘it depends’
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DMorison
Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1647 |
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The Beaver is strong with this one.....
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FrederikMA
Registered User Joined: 19 July 2017 Location: Copenhagen Status: Offline Points: 76 |
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Beaver's apostles are right. It depends. That is not to say it's not worth studying WHAT it depends on.
Unlike a speaker manufacturer, who resists to disregard all the things a preset depends when asked to do one for simple plug and play, a mix engineer has to develop a set of tools and guiding rules when facing real world scenarios. The Fletcher Munson is empirical derived and rests on assumptions and disregards other factors like time exposure (see ear fatigue) and signal type. Multiple curves has been developed for our ears' sensitivity to various kinds of signal. Knowing what the program material will demand from our systems is to me essential when designing the system Best regards, Fred |
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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If one was going to buy a book to help in this area would the Yamaha book be the weapon of choice?
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Pasi
Old Croc Joined: 25 April 2010 Location: Knutsford Status: Offline Points: 2733 |
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My favourite answer has been soon 10 years " It depends on application"
FOH doesn't need any EQ, if the system is good and placed correctly. Using RTA, assuming some phone program or similar, which doesn't use reference signal is waste of time as it can't tell you the important information. Hence you need a proper FFT system like Systune. After that you need to know what you are doing and what your aim is. |
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Conanski
Old Croc Joined: 26 January 2006 Location: Ottawa, Canada Status: Offline Points: 2515 |
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Edited by Conanski - 24 September 2017 at 11:26pm |
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1842 |
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There's your problem. You have used the wrong measurement signal, or haven't understood how to use that signal. Look at your pink noise signal in an RTA before it leaves the PC, or play back pink noise from an audio test CD, or test file into an RTA (hardware or plugin, whatever you use).
Oops, that doesn't look flat, does it? But what about this:
Your mistake was to EQ your system with pink noise as input signal so achieve the appearance of white noise. So essentially you EQ'd it to output white noise. Probably by boosting the highs a lot and cutting some bass. Any music you will put into the system after that will sound harsh and without bass. Pink noise resembles natural sounds and music more closely than white noise, but it has a downward slope, if viewed on an FFT RTA (as you can see in the pictures above), unless the RTA has a slope correction feature. I use a plugin called Voxengo SPAN that has this feature, there is a freeware version available. The slope correction compensates for the constant power loss to produce a flat spectrum line. On old-school "block display" RTA's (octave or third scaling, doesn't matter) pink noise should look flat as well, because a single vertical line represents the energy in a frequency band, as opposed to showing the values for all the single frequencies (which would result in a tilted line again). The frequency bands become bigger with rising frequency (they are relative number ratios, not fixed!!), and this compensates for the inverse power loss. Personally I think pink noise is more practical for system tuning. While both are not very pleasant, any substantial SPL level with white noise is quite painful without ear protection, and could be even harmful to the HF drivers if used at very high levels and for extended time. Also the mid and especially bass are very low in level compared to the high frequencies. Technically you have variations of two options: You could A) either just use white noise B) use pink noise and EQ for a downward sloping line C) use pink noise with an RTA (plugin) that has a tilt function D) use an RTA (plugin) that supports multiple simultaneously overlaid spectra (e.g. voxengo SPAN plus) -> overlay test signal with measurement mic input.
Edited by bob4 - 25 September 2017 at 3:08am |
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10920 |
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Three options - Use a dual channel FFT and MLS/ESS stimulus to compare what goes in to what comes out instead of an RTA.
It's almost as if REW wasn't free, and included a pretty decent manual on how to use it… Edited by toastyghost - 25 September 2017 at 5:09am |
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Foca_Dacian
Registered User Joined: 05 February 2011 Location: Romania,Cluj Status: Offline Points: 118 |
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I have used the RTA function on the Behringer X-32 for the measurement.
It overlays on the consoles screen the frequency response over a GEQ and is really easy to use. I have to read and see if it take into acount the sloping of pink noise, but regarding the results I have obtained , it most likely not. I have used the settings and stept in this instructional video from Music Group: this is the mic used for measurements: |
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Foca_Dacian
Registered User Joined: 05 February 2011 Location: Romania,Cluj Status: Offline Points: 118 |
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Thank you for the replies, staring to understand.
I have downloaded REW , reading the manual. What other paper do you recommend reading to better understand measurements and how to interpret them?
Is the ADC in the UR22 from Steinberg good enough for FFT measurements? Edited by Foca_Dacian - 25 September 2017 at 9:21am |
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