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[JamesJudson]

hey, I am trying to setup my speakers levels (SPL levels in my church). I am using an SPL meter app on IPad and trying to match the levels of mains and delays at the point of measurement ( which is deep into the audience at FOH). We have very bad acoustics and room treatment is not an option. I am setting up my mains to 85db SPL at front and measuring the amount of sound drop over the distance ( which is 79db with delay's turned off) and I turn off mains and firing delay's and setting them to be at 79db. It works just fine when I play music through the system but when pastor is talking there is no intelligibilty at the back. How do I need to setup my speakers levels so I don't excite room as much and also reduce the energy at the back so that energy reflected from the back wall is less and also having sufficient level of intelligiblity.

[Kevin Maxwell]

What mixer are you using and how are the delay speakers getting their feed?

[Matthias McCready]

hey, I am trying to setup my speakers levels (SPL levels in my church). I am using an SPL meter app on IPad and trying to match the levels of mains and delays at the point of measurement ( which is deep into the audience at FOH). We have very bad acoustics and room treatment is not an option. I am setting up my mains to 85db SPL at front and measuring the amount of sound drop over the distance ( which is 79db with delay's turned off) and I turn off mains and firing delay's and setting them to be at 79db. It works just fine when I play music through the system but when pastor is talking there is no intelligibilty at the back. How do I need to setup my speakers levels so I don't excite room as much and also reduce the energy at the back so that energy reflected from the back wall is less and also having sufficient level of intelligiblity.

Intelligibility for Western speech is about high-frequency content - when you are in a bad/reverberant room the lower/mid frequencies will muddy things up, and what sounds full up front will be mud in the back - for Western speech this does not work.

Try thinning out the mic quite a bit and it will be clearer in the back.

I once was mixing in a church that was an architect's dream, 167ft vaulted ceilings with all marble, tile, and glass. It was a nightmare for sound reinforcement and had 320 degrees of seating. For spoken word, I REALLY thinned out the mic. In the very front it was somewhat radio-like (and not in a good way), however in the back it was readily intelligible, and I was approached by several people who sat in the back and was informed they had never heard things so clearly. Audio is a game of compromises, and that is one I am willing to make.

For delays a few thoughts:

1. In general every time you double distance you half your volume.
2. Your delays should be time aligned to your mains (rather than simply volume matched) - you will want some measurement software for this so you can get a transfer function going - SMAART is usually what I use, but that is not inexpensive.
3. Your delays don't need to be fullrange, you may just want them adding that top-end back in - If you focus on top I would recommend doing EQ rather than a pass filter as EQ will affect the phase less and will make matching them up with the mains easier.

[Bill Meeks]

Another alternative to the rather expensive SMAART software is Open Sound Meter. It is donation-ware and offers the same basic analysis features as SMAART. Here is a link: https://opensoundmeter.com/en/. I've used both a demo version of SMAART and Open Sound Meter. For basic system frequency response and time alignment tasks the two are functionally identical in my view. OSM can measure and display magnitude, phase, and coherence.

[Jordan Wolf]

My by-ear method is to find where there is greatest overlap in the delay zone with the mains, take a distance measurement from that spot to the mains, take a distance measurement from the same spot to the delays, subtract the delay distance from the mains distance and convert to milliseconds - that is your delay time, and you can tweak from there using sibilant music and/or a ticking/percussive metronome type beat.

[John Schalk]

....but when pastor is talking there is no intelligibility at the back. How do I need to setup my speakers levels so I don't excite room as much and also reduce the energy at the back so that energy reflected from the back wall is less and also having sufficient level of intelligibility.

Hey James,
In a previous post you stated that your main speakers are QSC K12.2s and that there is also a distributed speaker system in the room.  Can you give us more details about the distributed speaker system as well as the other components of your sound system please?  For instance, what mixer are you using?  How big is the room and how far back are the fill speakers?

You really must use delay on the fill speakers to align their output with the main speakers as a first step.  Software tools like Smaart or Room Eq Wizard (REW) can give you precise measurements for a given location, but you can get close by using a laser measure or just a long tape measure.  My other suggestion is to roll off the low frequencies in the fill speakers. 

[Kevin Maxwell]

I agree with everyone on the time aligning of the delay speakers. But I would caution you about using a metronome or a cycling impulse sound like that to time align the speakers. The reason is that you can easily get lost at to which impulse is the right one, you can be an impulse or 2 out of alignment. I prefer to have someone at the mic with a device that makes an impulse sound doing it at a random time.

I asked about the mixer in use because if it is a digital mixer with Matrix outputs then one could feed the speaking mics at a different level to a matrix output to the delay speakers then is going to the main speakers. Also most digital mixer that have delay on the outputs also display the delay in time and different distance settings. So you can measure the distance from the mains to the delay speakers and use that to set the delay to that distance. It will usually be close enough for this need. 

[JamesJudson]

Hey James,
In a previous post you stated that your main speakers are QSC K12.2s and that there is also a distributed speaker system in the room.  Can you give us more details about the distributed speaker system as well as the other components of your sound system please?  For instance, what mixer are you using?  How big is the room and how far back are the fill speakers?

You really must use delay on the fill speakers to align their output with the main speakers as a first step.  Software tools like Smaart or Room Eq Wizard (REW) can give you precise measurements for a given location, but you can get close by using a laser measure or just a long tape measure.  My other suggestion is to roll off the low frequencies in the fill speakers.

My sound system is setup like this.....Mic's are hooked into stage box (Presonus NSB 8.eight), it is connected to mixer(Presonus 32SX) with ethernet cable. After processing mic's channel it goes into a subgroup (to ring out mic, this is  usually last step) and output of subgroup goes into main. Next in my signal chain is speaker management system's (Driverack Venu360) they are fed from matrix's from mixer. The speakers fed from Venu 360 and are time-aligned,tuned in Venu360 itself. My pastor's headset mic is DPA Directional headset. Also I put low shelf on delay's at about 300Hz and reduced them 8db.

[JamesJudson]

hey, I am trying to setup my speakers levels (SPL levels in my church). I am using an SPL meter app on IPad and trying to match the levels of mains and delays at the point of measurement ( which is deep into the audience at FOH). We have very bad acoustics and room treatment is not an option. I am setting up my mains to 85db SPL at front and measuring the amount of sound drop over the distance ( which is 79db with delay's turned off) and I turn off mains and firing delay's and setting them to be at 79db. It works just fine when I play music through the system but when pastor is talking there is no intelligibilty at the back. How do I need to setup my speakers levels so I don't excite room as much and also reduce the energy at the back so that energy reflected from the back wall is less and also having sufficient level of intelligiblity.

Also guys I heard many engineers say gain before feedback is independent of mic's sensitivity. But when I use Shure sm58 (cardiod) I found that GBF is more than when I DPA Gooseneck (hyper cardiod) why is that I don't understand.

[JamesJudson]

What mixer are you using and how are the delay speakers getting their feed?

Presonus Studiolive series III mixer and from matrix's (I am only sending main mix in the matrix)

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