Church Recording - Cheap MICS - Distorted Signal - HELP !!!

Posted: Sun Sep 09, 2007 3:57 pm

Newly drafted “sound guy” in Southern California needs help with Live Sound / DAW Recording in a church setting. I am computer GURU - however I am a new recruit at sound - but have had my eyes "open" - learning...

Here’s the situation. We have a Mackie CR1604-VLZ Analog Mixer. Through a 100’ snake we bring in 6 cheap MICS (lead guitar vocal, rhythm guitar vocal, 3 singers) (these Mics I saw at MusiciansFriend – like 3 for $129 like the Shure PG58 Microphones 3-Pack), Instruments: Lead Guitar Direct Box, Rhythm Guitar Direct Box, Bass Direct Box, and Keyboard.

The snake also takes the MAIN outputs and AUX outputs back to the stage area where there are 2 AMPS in an SKB case: a simple Low-Watt Mackie Amplifier for a few Monitors and a similar-value Peavey PV-1500 amplifier for the main speakers.

INPUT NEEDED HERE >>>---> We have a couple pieces of equipment not yet utilized: a Behringer 8024 Ultra Curve PRO, a Behringer MULTICOM PRO-XL MDX4600 but I have yet to incorporate them into the setup and would like some suggestions (clear ABC suggestions) as to their hookup – and their system value…

TODAY'S ISSUE: For the recording of the churches' Sunday message we have been routing the main Mackie Mix from the AUX #3 & #4 into a MOTU MKII 828 Firewire unit so as to bring the best possible audio into a PC running Windows XP Pro where I have captured the audio with Sony Sound Forge 7.0 and/or a simple Freeware Audacity program. In both cases I clean up the audio (post recording) using Sony Sound Forge and burn weekly CDs.

There are a number of issues - but I can filter down to 3 questions! Last week the MOTU went “south” and is no longer functional. While that is being addressed, I replaced it with an inexpensive $200 M-Audio Fast Track PRO to supply the computer via USB. Since the M-Audio is really new to me – I am capturing the feed with the very simple and straight-forward Audacity software.

Today I noticed that the “key signal” (the pastor's message captured by the "best" of one of the cheap mics) coming into the Mackie mixer (via Input #1) was distorted. I was monitoring the signal through the M-Audio headphone jack for recording purposes (via the Mackie CR-1604’s AUX SEND signal). In order to get sufficient-enough signal at the M-Audio box I was needing the Mackie's Input #1 trimmer set at significant +Db at 3 PM! Unity for the trimmer pot is 180-degree left at 9 AM.

As background information, - - - even without worrying about recording - - - it is necessary to keep this pot at 12 NOON for the main house AMPS to give us a decent house audio level. When I was experimenting today with the M-Audio to ATTEMPT to get a “clean” signal – I was unable to do get a non-distorted, muddy signal UNLESS the trimmer was at “U” (unity). When the Mackie Mixer’s Line #1 Trimmer is set straight UP or 90-Degrees right (12 noon to 3 pm) there is notable distortion on headphones - not so much in the noisy "house environment.". I checked the other mics too. Similar situation.

Main questions???

1) Would better MICS send more signal through the snake to the Mackie so that the trim could be set at the 9 AM “U” (unity) setting?

2) With the current MICS - - - or even with better MICS - - - are MIC Pre-Amps a good idea?

3) If Pre-Amps are a "good idea," are the mic pre-amps set up at the audio desk between the snake and the Mackie Mixer inputs?
[/b]

Posted: Sun Sep 09, 2007 6:15 pm

From what I can tell you are having trouble with "gain structure." Your mics are not a problem. You may not be crazy about the quality of the sound, but they will put out plenty of clean signal. Don't worry about preamps. The Mackie has mic preamps that you are adjusting when you adjust the top trim pot. They are arguably the best components in your rig.

The issue about gain structure is that every signal goes through a sequence of amps: preamp - individual fader - main fader - power amp. You need to adjust them so that you have the maximum difference between the noise floor and clipping. It's not rocket science, but it takes a while to learn and to explain fully. Read you Mackie manual. Search on this forum and google the rest of the web. There are several good tutorials out there.

Posted: Sun Sep 09, 2007 7:05 pm

Omigosh...cheap mics!
I HATE them!! But not for the reasons you've listed...
BR's right about the gain structure. BTW (hey, I'm using fancy computerese!), I thought that 12:00 was "Unity Gain" on Mackies...!
Read the owners' manual very thoroughly, especially regarding gains...
As far as the Behwronger (re: trademark issues) gear, the Ultracurve is a POC. At least if you believe the marketing hype that it will assist you with feedback control, keep the system clean, and make your teeth whiter...
The Ultracurve is not beneficial to most systems. It won't handle the output voltage that your Mackie can produce. And it doesn't do what they claim, anyway. A simple dbx 31-band graphic EQ will do you better. It won't drop the signal and will do what they say, cleaner. In any case, that EQ should be patched into the mains output loop.
To record the message from the pastor: The M-Audio should be fed by the MONO out of the Mackie mixer. I believe that there's a switch at that output labelled "-50dBm/+4dBm" for that output. The "-50" position is to be used to feed a MIC level input on the M-box. The "+4" should be used if you are feeding a "line level" (significantly stronger level) input on the M-box. Applying the correct level settings will result in drastically cleaner sound.
As far as the Multicom is concerned...let's wait until you get the other stuff taken care of. We need to deal with thresholds and ratios before you get that portion done...you gotta walk before you run...
BTW, Shure's PG mics are pretty so-so. Don't blame them for distortion,but don't buy any more!!!

Posted: Sun Sep 09, 2007 7:23 pm

OK, I made a mistake in that there is NO "-50/+4" switch on your mixer for the Mono out (or anything else, for that matter). Mine has it. Yours has a rotary level control. Start it out LOW, slowly bring it up. At least it lets you adjust the level....

Posted: Fri Sep 14, 2007 8:33 am

I agree that it sounds like a gain issue.

Here is what I would do.

To the mic line for ch 1, set the fader 1/2 way up or just under the 0 midway point, (-5 to +5 is the clean zone) adjust the Gain/trim (the top dial on ch 1) slowly up untill you see the signal start to light up at the #1 fader. bring it to the top of the green but no higher.
The signal for that channel should now be strong enough that you wont need to push the master faders to high. If at this point the signal is not clean then you need to look for a poor conection and you need to make sure that all the other channels and FX and settings on the mixer are off.
Go through each channel, line/connection and mic to trace down a bad component/connection. what I mean is you can try things that dont work (mic or cable) on a channel that does.

I hope you find the problem and happy recording

Posted: Sun Sep 16, 2007 2:03 pm

Sunday UPDATE...

So THANK YOU guys!!! for the input (regarding my inputs!). A week has passed and I tried many of the things suggested AND a couple specifics: I connected the M-Audio Fast Track PRO to the Mackie MONO (Out) - (yup - the one with the pot below it). The signal was both strong and adjustable.

Moreover, I worked the various inputs over from the Mics and Instruments on stage back to the Audio Booth and to the Mackie. I was able to get most of the trimmers in the UNITY area by methodically working them one by one as suggested. An increase in the MAIN House AMP's settings was helpful too (The AMPS are at the stage and sometimes it's a SET and FORGET part of the system (for me). Anyway the increased volume setting on the AMPS allowed more flexibility at the Mackie in that the POTS, Input Faders and Mains could be set lower thus not driving up the signal needlessly there. When the system was reviewed Input by Input - NO notable distortion, no unreasonable hum...

Virtually all of the signals from the stage to the booth were strong and usable including the cheap MICS - as suggested in a post they DO put out signal - no matter the cost... The only exception? Input 11 - for whatever reason (no matter what DirectBox is used) I pick up a Los Angeles Korean Radio station on that input going on 2 years now (I suppose that is a whole new thread Wink

).

After the methodical line tracing and listening (on the Mackie headphones) I switched over to computer recording end of the booth. During practice this morning there was still discernible HUM detectable on the M-Audio's headphone jack - thus the recording stream too. The Mackie MONO (Out) is 1/4" TRS and all I could find (this is a church - not a studio) were a couple of fabric-covered, better-quality (not super) 1/4 TRS guitar cords. I tried a 10-footer - HUM! I tried a 20-footer - HUM and snap-CRACKLE-pop at the connectors (both sides of the cords!). I remembered that I had a HOSA-Brand 8-channel, color-coded, molded termination (inexpensive) recording snake that I had for the (NOW FAILED) MOTU 828 MKII. I utilized one lead of the eight possible: Q-U-I-E-T !!!

Of course, the connectors are all vinyl or PVC and that also eliminated the crack and pop of the connection - even when touched.

Are Guitar cords and recording snakes & patch cords THAT different? Are they never to be interchanged on one side or the other of the MIXER?

Regardless of the answer to the cable question - THANKS AGAIN - Clean, recorded signal for our "Pastor Dude..."

This topic sponsored by: