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Old 20th March 2013, 01:23 AM   #1
hewo is offline hewo  United States
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Default Mixer Extremities Hardship

1. Need help resolving strident nature of PA repro for a guitar channel.
2. the 8" paper speaker of a class A single ended el84 guitar amp is captured using an aircraft pilot's mouthpiece sensor (same as lapel because it requires battery excite).
3. the output was written into the laptop and affirmed full spectrum. playback of the file very impressive.
4. next, the 50K:600 transformer (super tiny) was appended to provide the mixer balanced output. the mixer is about 65 yards distant from stage.
5. the PA repro sounded a bit strident. i asked the engineer whether the guitar balanced signal was either TOO BIG or TOO SMALL. but i am not certain whether he knows what a healthy incoming balanced signal is suppose to be, rms ac voltage, say, 250mV rms maximum?
6. when the mixer channel is operated to either extremity (full blast or choking) frequency favortism does occur. full blast enhances lows while choking accentuates highs. it's the nature of frequencies and circuitry that this occurs.
7. but the limitation of other channels necessitated attenuating the guitar signal for a proper integrated mix. and this is where the strident nature resulted.
8. the sensor came equipped with an orifice rubber mask, super tiny apperture. should i reinstall it? be aware the sensor assembly (including lithium, microswitch, polarity diodes protect, audio coupling cap and output impedance resistor), is affixed (3M gel mounting tape 1.75mm thickness) centershot onto the perforated steel grill. the apperture is tinier than the perforation diameter. the assembly was optimized for minimizing paper speaker obstruction. the assembly is one half of a wrigley's legacy chewing gum stick. current consumption is .2ma to .5ma according to audio demand.
9. the paper speaker is operated at 2 to 3 acoustical watts, but its apparent loudness seems more, maybe because of the class A topology and/or overly large pt and ot.
10. ac rms voltage output (coupling cap) operation fluctuates from zero all the way up to 870mv ac. is this way too big? the transformer must be around eleven to fifteen into one, isn't it?
11. thanks in advance to your assistance - worship is so important but there's no techies in the church.
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Old 21st March 2013, 01:09 AM   #2
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Well, nobody is helping. I would replace that speaker and microphone contraption with a transformer and a pot, to get the signal down to what a mixer would expect. You need the speaker to tell yourself what you are doing, but the mixer input doesn't. I would isolate the guitar amp from the mixer with an audio transformer like a triad SP50. (500 ohm in , 600 ohm out, 50 mw). This can break up potential ground loops, and reduce hum. Then I would put a pot on the input of the transformer so that the guitar output can be turned down. You don't want to saturate the transformer with too much voltage. That pot will give you, the musician, some control over the output.
Furthermore, sound men in churches have a lot of enthusiasm and often not much training. I would train some kid to make a chord on your guitar, then go back to the sound desk in a rehearsal, have the chord played, then see if you can get the sound you want out of the mixing equipment. Be aware, that you as a musician, possibly with damaged ears, may like things louder than the audience does. Church people tend to see the only music as "the word", with some textual support. Instruments are tolerated outside the C of C churches, but the preachers/ministers/elders/deacons/priests/major donors are often not as enthusiastic about the instruments as the musicians or the instrument's donor. But you can try to adjust things to that the distortions or frequency emphasis do not occur.
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Last edited by indianajo; 21st March 2013 at 01:17 AM.
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Old 21st March 2013, 11:45 PM   #3
hewo is offline hewo  United States
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the music store mgr advised relocating the sensor more outboard and not to use centershot because here upper frequencies are clustered intensely. i will try this 1st.
2. if still inadequate, i will replace the pilot's rubber mask (super tiny) over the aperature. the mask has a fractional millimeter hole allowing sound pressure entry to the sensor. effectively, it is an orifice, so i do not know how the varying wavelengths of the spectrum will behave as they squirm their way through the orifice. acoustical waves act differently from electromagnetic radiation. my own gut feel is that interaction occurs whereas in radiation, the dissimilar wavelengths do not interact.
3. all i really care about is how many congregates turnover to the Lord. i don't get to watch them because my eyes are glued to the frets but the soundman told me to look up and see tears. i fumbled doing so. but he was correct and you too. the choir and lead vocals plus the script meaning infuses them significantly. this is celebrate recovery and it will be upheld (couple hundred now).
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Old 22nd March 2013, 12:16 AM   #4
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Make life easy for yourself. Scrap that mic and transformer, and get yourself a Shure SM57. Plug it in, and wrap the lead around the handle of the amp so it hangs in front of the speaker. Sorted.
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Old 22nd March 2013, 12:41 AM   #5
hewo is offline hewo  United States
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pinkmouse
1. we already tried it - too boomy (is the cartridge vibrating against the steel perforation grill?). but when a mic stand is used and no contact made to grill okay. humbug clutter though
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Old 22nd March 2013, 02:21 AM   #6
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Quote:
humbug clutter though
What is humbug clutter ??.

Dan.
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Old 27th March 2013, 12:03 AM   #7
hewo is offline hewo  United States
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clutter humbug is unsightly appearance and hazard footworking. pinkmouse was followed as the phantom blew the package. phantom to the secondary induced into primary whalloped the package. i need to replace the tantalum, it can't stand reversals. the dangling pearlet mic obstructs the paper significantly and i have blown ears from historical decibels.
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Old 2nd April 2013, 05:17 PM   #8
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ahh the age old reproduce my distorted guitar sound through the pa like i hear it scenario.
even the pro's are still working on an solution to that one.
i can only attest to what has worked for me not that my method is an ultimate solution.
first and foremost distortion is a double edged sword it can make or break a player and his sound. i'm kinda of the less is more sort, just enough to get the point/tone across without becoming non linear or uncontrollable. also on this point are you setting up your sound without other competitive sources playing at the same time as in coming up with that ultimate tone sitting in your jam space and then wondering why it doesn't work in a playing situation?
more to the point using two mic's of different types as in large and small diaphragm types on the same source(your amp) but adjusting position and distance of both to obtain a better balance/ blend of the complex waveform that your distorted guitar is.
there is so much about this topic than can be properly discussed in this forum.
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Old 2nd April 2013, 11:26 PM   #9
hewo is offline hewo  United States
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yup sounds about right. the captain turns my guitar onboard controls down because we are in close proximity (pianoist two, lead vocalist three, choir twelve, drums one, bass one, acoustic guitar one, electric guitar one). then i must face my eight inch paper speaker, buttocks to congregation rude. it was better unmiked eight inch paper speaker. but captain worship says must go hot to pa. sounds horrible with tempered loudness of paper speaker. i should ask congregation what they hear on the floor.
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Old 3rd April 2013, 12:51 AM   #10
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ok you are between a rock and a hard place.
asking the congregation is only going to confuse the issue further.
can you direct me to captain worship i'd like to ask him his take on the situation.
in the mean time after checking your profile that really doesn't tell much about you i'm not sure how to advise you in reaching a solution to your obvious problem.
can i ask what amp are you using?
you said it was like a 2 or 3 watt class A output?
what are you using for distortion and pre-amp/combo into this 8 inch speaker you talk about?
and why in god's name are you using a microphone that was by design never intended to be either wideband or sensitive and expect a good result?(you did say it was from a pilot's headset, if it's a noise rejection type your doubly screwed)

please define "tempered loudness"

Last edited by turk 182; 3rd April 2013 at 01:02 AM.
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