[Bobby1note]

Joe, I'm going to add some thoughts here, based on the assumption that the Mackies cannot be moved.
I've added some responses below, however, let's hold off and see what they say this Sunday about moving the Mackie's. My fiance thinks we have a good case as long as we can figure out a solution to the cabling. But please see my responses below.

Joe, You probably don't need more cabling for the Mackies, since moving them to the shelves, will be closer to the mixer than they are now,,, plus,,, you should have a bunch of spare XLR cables left over from your unused mics. In a pinch, just join them end-to-end. I wouldn't splice cables.


Do you ever get time to do a sound-check before the service? If not, what about after the folks have left?
This is a constant struggle, because I don't ever get to soundcheck with the choir. Our choir is volunteer so they show up about 5 minutes before service. Thankfully, most of them are seasoned with the songs so they know about 95% of what we play. If there's a new song, my fiance and I grab a mic and lead it during service to introduce it. But, I can do some soundchecking after the service as there's no service after us and I have some time.

Cool.


Starting at the loudspeakers rear panel, you should ensure that "contour" is set to "flat, (which will eliminate slight lo and hi frequency boosts), and, I'd like you to engage the loudspeakers HPF (hi-pass filter). This really should not have a negative impact on the voices, nor the guitar, and possibly very little effect on the piano. That HPF will activate a lo-cut filter that rolls off the lows at 75Hz and below, but not completely. There's a "slope" to that filter, and at this point, I don't know precisely what that slope is. -12dB per octave is my guess, but I'll try to find out for sure. Could be less, but I doubt it's more. For the moment, I'd rather you use those HPF's, than the HPF's on your mixer-channels. Also, those are "shelving type" EQ's.
I can confirm that the contour on the Mackie's are already set to "flat", I make sure of this every service when I turn them on. I can also confirm that the HPF (or "Low Cut" as Mackie calls it) is also already enabled.

Good stuff!!

Your consoles' GEQ has notch filters, not shelving type, and they're wide-band, so I'd like you to use those as little as possible,,,,, with one exception. The next time you run across a very hi-frequency feedback "chirp", try a 6dB cut at 4 kHz on the GEQ, then try to bring it back slowwwwwly to -3dB, and see if that helps. I'm not trying to completely fix that problem,,,, I'm simply trying to find out where that "chirp" is occurring, and 4kHz is not uncommon. Later, we could look at using a much tighter 31-band EQ, to surgically remove that chirp. These EQ's are much cheaper than outboard parametric EQ's.
After the service, I can force the feedback and then try the 6dB cut on each of the EQ sliders starting with 4kHz to see which affects it most. Not sure that I'll be able to do this during the service as there's always a quick stare down from everyone to pull the main fader to cease the feedback. I'll try to narrow it down though.

It can be very tricky to find short bursts of feedback, (intermittent feedback). They don't hang around long enough for you to react. If they last a bit longer, it's fairly easy to find,,,, but very annoying to an audience. Later, if I remember, I'll tell you about "cowboy hat" feedback.


At your mixer, I'd like you to engage ALL of the channel HPF's, and, I'd like you to "mute" ALL of the unused channels. Make sure that those channels' EQ's are all "flat", and that the faders are all pulled back. Turn the gain-knobs back as well. Why on the unused channels??? Well, that's because these small consoles can have a lot of "cross-talk" between channels. We want to eliminate the possibility of that occurring.
Now here's some sound engineering basics that I'm proud to say I've followed. I can confirm that the first thing I do before each service is pull back all faders/gains/AUX/EFX, mute all channels, set all channel EQ's to flat, center all PAN and enable the HPF/Low-Cut on all channels. Then, I adjust each channel one at a time.

Excellent practice to follow. Good stuff!!!


Joe, I'm going to give you a tool that will help identify the feedback frequency you're sometimes experiencing. This is an on-line "feedback trainer". Download this small program (free), and play around with it a bit. It's a great tool.

here's the link;
http://sourceforge.net/projects/sft/#screenshots
Thanks so much for this, never knew something like this existed! Super excited to try this out!


Joe, that feedback trainer is a bit quirky to use at times. It just takes a bit of getting used to. Obviously, it looks like the front panel of a 31-band GEQ. When you hit "start", it fires up a sequence of different frequencies, and you simply pull down on the fader that you think is causing the feedback. It holds that frequency until you find the right one, then moves on to the next. Now, if you look at the top of each fader, there are "buttons" across all the frequencies. Instead of going to "start", just click on those buttons (maybe hold them down, I forget), and you'll hear the sound of each frequency. I hope you're better at it than me.

Once you get used to it a bit, you'll notice that the really low frequencies have a "rumbling" quality,,, and as you go above 100Hz or so, you'll notice that the sound has a "baritone-sax-like" quality,,,,, and as you increase the frequency, you'll notice a "flute-like quality,,,, then a picollo-type quality to the sound, until you get up into the really high frequency range, which can be ear-piercing. You'll probably have a hard time hearing those, because your computer speakers probably don't get there. Associating the different frequency bands with instruments, helps you get in the ball-park quickly.


Thanks again so much Bobby!

My pleasure Joe.

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