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wcerto
Ahonui
USA
5052 Posts |
 Posted - 07/19/2007 : 2:57:30 PM
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How to make the electronical gizmos not feedback? Paul and two nephews were playing at Ma's 90th birthday party on Sunday. Paul was in the middle and the two young boys (age 17 -- good guitar/piano/drum players) were on either side of him, maybe 8-10 feet apart. When Paul picked up the Mike to tell everyone that we were ready to eat and for his brother to give the blessiing, OOOOH....ouch.....blow your ears right off your head. Why the thing does that? Sounds ugly. Paul said he doesn't use that stuff enough to learn how to do it right. I think it is a condenser mike whatever the heck that is. He has a monitor which he usually puts behind him. Also usually he has more space between him and the wall behind h8m, but this time he was pretty close to the wall - maybe 3 or 4 feet. He has one pick-up thingie in/on his guitar...I don't know what the heck. It is one Simon & Patrick 12 string acoustic made outen cedar (smells good in the case). They boys played acoustic sometimes and electric sometimes. I think it is one kind Craven amp or speakerse or something. No tubes, I don't think.hey each had their own mics. Hurt the ears! Sheesh.
What kind of books out there to learn how to use all this equipment to make nice sound?
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Me ke aloha
Malama pono,
Wanda |
Edited by - wcerto on 07/19/2007 4:46:23 PM |
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noeau
Ha`aha`a
USA
1105 Posts |
Posted - 07/19/2007 : 4:58:13 PM
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| Yah, the pros can jump on this but I do know that volume and equalization have something to do with it. Monitors behind the speaker (ie the person talking or singing ) feed back into the mike and starts a feedback loop. And so on and so forth. High freq versus lo freq feedback have different reasons for doing so too i tink.. Any let the pro sound guys in the lo'i explain moa scientifically if dey like. |
No'eau, eia au he mea pa'ani wale nō. |
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Retro
Ahonui
USA
2368 Posts |
Posted - 07/19/2007 : 6:02:20 PM
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Tell him to put the monitor in front of him, rather than behind, probably pointing up from the floor. If the mic's pickup pattern is cardioid (most common), then imagine pushing the mic into a balloon (without breaking the balloon's wall.) Can you envision how the balloon "bends" around the mic? That's a cardioid reception pattern. See where the "dent" is, where you are pushing into the balloon? That's where the mic is least sensitive to reception --- and that's where any monitor speaker that's amplifying the mic's signal should be pointing. So the sound coming from the monitor is going towards where the mic is least sensitive; thus less likely to get feedback.
Condenser mics are more sensitive than dynamic mics, too. If the pattern is omnidirectional, monitor placement gets a little trickier, because the mic's reception area is spherical, as if the mic were inside the inflated balloon. If you cup your hands around the mic, either the head of the mic, or the little side-ports (slots along the body of the mic, if it has 'em), that affects the mic's pickup pattern, too, and feedback can result. |
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hapakid
Luna Ho`omalu
USA
1533 Posts |
Posted - 07/19/2007 : 7:56:49 PM
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Often the culprit is a transducer or under-saddle pickup in an acoustic instrument. These are free-floating microphones mounted on the sound boards of the instrument. They pick up any ambient sound and feed it back instantly. In highly amplified situations, the acoustic instrument often must play through channel or a microphone that is isolated from the rest of the band.
Jesse Tinsley
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rendesvous1840
Ha`aha`a
USA
1055 Posts |
Posted - 07/20/2007 : 2:06:15 PM
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OK, now to start over. The monitors weren't hooked up, because I needed them for the stereo in another part of the room. So no monitors. My 12 string has no onboard pickups, I use a small Audio- Technica PRO 7a condenser mike. It clips on at the soundhole. Combined with the cedar top, monitors feed back real easy, so that has been a problem in the past. But the mons were elsewhere that day. The main speaker/amp is what was behind me, as I hoped to use it as both main& monitor.The vocal mike is a Shure PG 58 dynamic cardioid. When I went to turn it on and announce dinner, I didn't bother to get in between the mike and the speaker. Plus, the mikes were on, and the volume set to play when I turned the amp power on.This is one of those "How many mistakes can you spot in this picture" deals! 1) Volumes both should have been off. 2) Mikes should have both been off. 3) With me sitting down the mike would not have been pointing at the speaker. Those are the ones I came up with thinking about it. How many did I miss? We moved the speaker out in front of me to play and had no trouble, except I couldn't hear me without a monitor. My nephews' amps were off at thie time of the feedback. Only one had a vocal mike, he ran it through a Karaoke machine, as we had no other equipment available. I normally play alone and haven't explored this band situation fully. The boys usually play in a metal band. We've jammed, but never played together outside of my house. I have a small mixer, and could have run mikes into it, and used the amp strictly as a power amp. Haven't had this stuff out of the closet since September, and need to get more familiar with these toys.Now, send me the OTHER kind of feedback. Thanks, y'all.
Paul |
"A master banjo player isn't the person who can pick the most notes.It's the person who can touch the most hearts." Patrick Costello |
Edited by - rendesvous1840 on 07/20/2007 2:09:49 PM |
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Lawrence
Ha`aha`a
USA
1597 Posts |
Posted - 07/20/2007 : 3:35:25 PM
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Feedback is a very common part of any live sound amplification system.
Why?
Because it is an AMPLIFICATION SYSTEM!
...that means the sound coming out of the speakers (wherever they are) is louder than the sound going into the microphone. If the speakers are in the same space as the microphone then the microphone will ALWAYS pick up some of the sound of the speakers. If the amount of sound that the microphone picks up from the speakers is equal to or greater than the original sound then the sound will build up rapidly into a howl or squeal because it is going from mic to speaker to mic to speaker and building up each time. This is called uncontrolled feedback (or just feedback). The frequency of the feedback tone is determined by many factors: 1) the speaker response 2) the microphone response 3) the distance from speaker to microphone and 4) the room characteristics.
How to control it? (or stop it):
1) Don't point the speaker at the mic or vice versa
2) Keep the mic and speakers as far apart as possible
3) Use a dead sounding room (not a live one).
4) Don't turn up the amplifier(s) too much!
There are lots of fancy feedback stopping devices on the market these days, but they cost a fair amount, they work kind of so-so and you need to be very familiar with sound and acoustics to get much out of them. They mostly fall into the category of computerized intelligent parametric notch filter banks (and if you do not understand what I just said then you should not use one... until you DO understand).
The rest is just learning how your particular system behaves and staying away from dangerous settings and conditions.
P.S.quote:
I think it is one kind Craven amp or speakerse or something.
I think you mean CARVIN amp...
...but CRAVEN would be an excellent amplifier/studio equipment name and I would suggest that you register it immediately!!.
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Mahope Kākou...
...El Lorenzo de Ondas Sonoras |
Edited by - Lawrence on 07/20/2007 4:46:14 PM |
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