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[Shad Hall]

hi,

i'm back again to seek more of your all's wisdom and knowledge. in regards to a recent article from psw on Alternative & Effective Approaches To Sound Check by dave rat, i have a question or three hundred. lol my questions are particularly related to the section on pg2 called, "back in the day".

this past sunday evening service, i tested out his mixing theory at church for the entire evening; rehearsal and service. i am using an allen&heath gl2800 32-channel for that service.

right away, i saw the potential benefits to this style of mixing, but ran into some high pitches that according to this interactive chart was in the 12Khz range at about -30 to -15dB, from time to time. (note: these figures were established on cheap faulty desktop speakers just now, so actual figures might differ slightly.) as soon as this frequency was apparent, i quickly turned down the gain rotaries on the respective channel. i noticed that the two mxl 991(no sweetwater link) condenser mics used on the piano was giving me a lot of hassle, so i muted those two channels. there is one more condenser (same model) being used on the electric guitar amp. due to time constraints, i was not able to isolate if the guitar amp mic was also a problem or if maybe just those two piano mics have deteriorated over the years of use and handling.

when the musicians (piano, keys, aco-guitar, ele-guitar, 9 vocals) were finished, i muted the "vocals" section and the "instruments" section on the board, only leaving the pulpit "live". later in the service, when the musicians performed another piece, i un-muted those two sections and got some nasty 12Khz @ about -15dB, which i instantly re-muted those two sections and brought the gains down before un-muting them again.

i'm sure you will have questions for me, so i will end here for now.

thanks in advance,
shad


p.s. i just watched the three polarity videos on dave rat's website and wonder if they might have something to do with this 12Khz feedback. i probably should sketch up a floor chart to post here. but this topic might be better for a thread of its own...what do you suggest?

[Tom Young]

Were these 12kHz "pitches" sudden feedback (ringing) or were they longer (in duration) and broader tone characteristics in this frequency range ?

How does the current behavior differ from how things sounded before ?  

What are the physical locations of these problematic mic's to the stage monitors (that they are fed into) and the FOH speakers ?

Are you feeding the monitor system from this same console and, if so, are you aware that what you are doing with the input trims is effecting the stage monitors, as well as the FOH speaker system ?

Dave's article and technique are "right on" but virtually any written description of "how to" in live sound requires lots of experience, intuition and/or trial and error.

Finally, you would be much better off downloading a free RTA (real time analyzer) shareware program and measuring what is going on, as far as tone and feedback, in real time and saving screen captures. Allen & Heath used to have a good one at their website and it may still be available. There are others. Google.

Such measurement is not the appropriate tool to help you equalize (optimize) speakers. But it can help you to see what is going on as far as base frequency response and the occasional short-term anomaly (feedback) while you are mixing.

[Shad Hall]

alright, let's see if i can efficiently and succinctly answer your questions...yeah, right. *sarcasm* lol

Tom Young wrote on Thu, 23 September 2010 04:59

Were these 12kHz "pitches" sudden feedback (ringing) or were they longer (in duration) and broader tone characteristics in this frequency range ?

of the times i was able to quickly turn the gain down a particular channel, the 12Khz pitch was a sudden feedback and i knew exactly what it was, compared to the other times, i had to hunt through the different channel gain knobs to find the 12Khz pitch that lasted longer in duration, which i was able to do generally pretty fast.

Tom Young wrote on Thu, 23 September 2010 04:59

How does the current behavior differ from how things sounded before ?

this question has been on my mind all week. simply put, it was excellent before. lol don't fix it, if it's not broken, right? the friday night before i changed everything, we had a huge event with lots of guest speakers and lots of different guest music ensembles (without any rehearsal at the venue). afterwords, the live sound tech (40 years in the industry) who set up the church several years ago-tho isn't affiliated with the church anymore, congratulated me on a well-mixed without incident event (5pm~12am). let me clarify, that i'm only mentioning that to establish that the idea of the sound being "excellent before" is not merely my opinion. yes, i'm good at the art of mixing, but i'm also young and have lots to learn.

the reason i wanted to try out dave rat's approach was due to the fact that i rarely get the signal meaters on the board to light up. i figured that they're kind of there for a reason and if i'm not seeing them, then the board could probably be set up more efficiently.

Tom Young wrote on Thu, 23 September 2010 04:59

What are the physical locations of these problematic mic's to the stage monitors (that they are fed into) and the FOH speakers ?

i have attached a diagram sketch of the stage for your reference. also, here is a "live" picture to help you visualize the diagram sketch. (keep in mind these differences between these two files: there are two additional vocalists, a bassist and a drummer than regular. also, the cellist is a regular now, tho not there on the night this pic was taken.)

• the piano monitor (aux #5) might be picked up by the two piano condenser mics.
  
• the piano mics might just be picking up the sound reflecting off the back wall from the wall-mounted aux #4 (illustrated in the diagram sketch).
  
• similarly, the condenser on the electric guitar amp could be picking up the sound from the wall-mounted aux #1.
  

Tom Young wrote on Thu, 23 September 2010 04:59

Are you feeding the monitor system from this same console and, if so, are you aware that what you are doing with the input trims is effecting the stage monitors, as well as the FOH speaker system ?

yes, i am feeding the monitor system from the same console. before i applied dave's approach, i turned the monitor masters from about 1:30 to about 9:00-ish on aux 1~5. then for each channel, after muting it, i turned all auxiliaries pots down to infinity, gain and fader as well. with the channel signal outputs addressed, i turned the gain up until i got some signal meter lamps to light up. unmuting the channel with still having everything turned down, i brought up the house to briefly test it. i pulled the fader back to infinity and with quality ear phones, adjusted the necessary monitor mixes for that channel.

Tom Young wrote on Thu, 23 September 2010 04:59

Dave's article and technique are "right on" but virtually any written description of "how to" in live sound requires lots of experience, intuition and/or trial and error. Finally, you would be much better off downloading a free RTA (real time analyzer) shareware program and measuring what is going on, as far as tone and feedback, in real time and saving screen captures. Allen & Heath used to have a good one at their website and it may still be available. There are others. Google. Such measurement is not the appropriate tool to help you equalize (optimize) speakers. But it can help you to see what is going on as far as base frequency response and the occasional short-term anomaly (feedback) while you are mixing.

i understand that there are different valid approaches to mixing and presenting live sound and though everything "sounded" good for us, i didn't have any pretty blinking lights very often on the channels or master signal meters. anyway, after the sunday evening service, i reset everything to the way it was friday night, until i can get a better handle on this new approach. wouldn't it be good for me to have the signal strong enough to be referenced in the signal meters?

as for the sound measurement utilities you mentioned, i understand what you're saying and will look into them.

thank you for your time, patience and support. really.

[Dick Rees]

Ah, the old condenser mic(s) on the piano conundrum.  You probably saw this thread when it was current, but it's worth a re-read.  I posted my favored technique for getting good quality, usable sound out of a grand in a high spl situation.  If you want to hear the mp3 file I can probably find it and set it up for a download.  Shoot me a PM if you want to listen.

http://churchsound.prosoundweb.com/index.php/mv/msg/15231/0/ 40/e54535abc67cd9bbc579e2d57df7874d/

[Tom Young]

If you previously did not have HF feedback and by employing the method outlined by Dave Rat you now do have feedback, it is evident you have raised the gain of the system and it is now unstable (prone to feed back). I am surprised you did not appear to hear an increase in volume levels.

You can utilize Dave's technique and achieve reasonable signal levels with the LED indicators on the mixer but you must apply compensation gain (reduction) further up the signal chain from the mixer. For both FOH and stage monitors.

[Matthias Heitzer]

I would advise to use the method dave descirbes one paragraph before, unless you have to mix an orchestra in a suitable environment. Even though he talks about "fairly close mic'ing", if he used 24 mics for 60 instruments, thats a totally different situation than normal close miking. and since he did not mention monitors, i assume none were used. Remember it was an orchestra. The instrumentation and positioning was optimised during several centuries to sound good without electroacoustic amplification.

This orchestra-story is a pretty extreme example. IMHO, the main intend of his article is to get rid of those useless 2-hour knobtwisting marathons usually called "soundcheck".

[Michael Robertson]

I hadn't seen that article until just now. Strangely enough, I didn't know there was any other way to do soundcheck. That's the way I prefer and have done it for years. It's always worked pretty well for me.

[Shad Hall]

Matthias Heitzer wrote on Sat, 25 September 2010 03:59

I would advise to use the method dave descirbes one paragraph before, unless you have to mix an orchestra in a suitable environment. Even though he talks about "fairly close mic'ing", if he used 24 mics for 60 instruments, thats a totally different situation than normal close miking. and since he did not mention monitors, i assume none were used. Remember it was an orchestra. The instrumentation and positioning was optimised during several centuries to sound good without electroacoustic amplification. This orchestra-story is a pretty extreme example. IMHO, the main intend of his article is to get rid of those useless 2-hour knobtwisting marathons usually called "soundcheck".

good points you made. i will get back to this thread soon as i can finish rebuilding the master brake cylinder and other stuff on the el camino; my only mode of transportation at the moment...well, a bicycle doesn't count.

cheers

[Shad Hall]

hi again,

okay, i'm back to reply and conclude this thread as promised.

the piano mic feedback issues i had were due to a bad mic, which i have recently isolated after much process of elimination. i looked at the link(s) provided in this thread. last night, i found this site with an amazing piano pickup that does not pick up any bleeding noise from other instruments. amazing item and you should definitely check it out. if any of you happen to use one of their models, i'd like to ask you a question or two about it.

so for all of the adjusting on the sound board as mentioned early in the thread, i am now pretty confident that the 12khz squeal was caused by piano mics.

thank you all for your continued support and patience.

[Brian Ehlers]

I've never used that device, so I really shouldn't comment.  But I can only imagine that a magnetic string-sensing pick-up will sound about as much like an acoustic piano as a similar pick-up sounds like an acoustic guitar.  I've never heard a guitar pick-up yet which sounds "natural" unless it's supplemented with a microphone (in- or outside the guitar).

I don't buy the manufacturer's claim:  "Although it's not obvious to the casual observer, the entire sound we recognize as the piano is contained in the string vibrations."  I guess we should tell Steinway and Sons they're wasting their time with that silly sound board.

Still, they offer a 90-day money-back guarantee, so if you want to try it and like the sound, more power to ya.

I know that everyone's situation is different, and I recognize that my church doesn't run hideously loud stage volumes.  But I've never had troubles getting a natural piano sound, I've never had troubles with excessive bleed into the piano mic, and I've never had troubles with feedback through the piano mic.  This holds true for using either a stand-mounted cardioid condenser or a little omni taped to the cast iron frame;  quarter, half, or full stick.

I don't really understand your uncertainty as to which mic is primarily responsible for the feedback.  That shouldn't be too hard to isolate.

12 kHz is pretty high.  Feedback at that frequency is usually only caused by getting a loudspeaker or reflective surface very close to a microphone.  Do you have the piano lid completely closed?  Usually not a good idea.

Another possibility is that the feedback is through an electronic, not acoustic, path.  Check your signal routing both inside and outside your console.  Are there any continuous loops -- outputs which get wrapped back to their own inputs?

[Shad Hall]

Brian Ehlers wrote on Tue, 26 October 2010 14:42

I've never used that device, so I really shouldn't comment.  But I can only imagine that a magnetic string-sensing pick-up will sound about as much like an acoustic piano as a similar pick-up sounds like an acoustic guitar.  I've never heard a guitar pick-up yet which sounds "natural" unless it's supplemented with a microphone (in- or outside the guitar). I don't buy the manufacturer's claim:  "Although it's not obvious to the casual observer, the entire sound we recognize as the piano is contained in the string vibrations."  I guess we should tell Steinway and Sons they're wasting their time with that silly sound board. Still, they offer a 90-day money-back guarantee, so if you want to try it and like the sound, more power to ya. I know that everyone's situation is different, and I recognize that my church doesn't run hideously loud stage volumes.  But I've never had troubles getting a natural piano sound, I've never had troubles with excessive bleed into the piano mic, and I've never had troubles with feedback through the piano mic.  This holds true for using either a stand-mounted cardioid condenser or a little omni taped to the cast iron frame;  quarter, half, or full stick. I don't really understand your uncertainty as to which mic is primarily responsible for the feedback.  That shouldn't be too hard to isolate. 12 kHz is pretty high.  Feedback at that frequency is usually only caused by getting a loudspeaker or reflective surface very close to a microphone.  Do you have the piano lid completely closed?  Usually not a good idea. Another possibility is that the feedback is through an electronic, not acoustic, path.  Check your signal routing both inside and outside your console.  Are there any continuous loops -- outputs which get wrapped back to their own inputs?

ah yes, the silly soundboards by steinway & sons. lol

i think you have a thought provoking argument, but my thinking, right or wrong, is that the only way a person might be able to distinguish a "natural" piano versus a piano using the aforementioned system, is if they were in a concert hall and the the piano was a solo instrument. i think that once you add 10 individual vocals, 2 guitars, keys, violin and cello as regulars with occasional drummer and bassist, i'm not so sure anyone could distinguish if the piano was using these pickups or not. from what i read on their site, forums, testimonials (and the list of well-known musicians using them. wow!), the benefit to was the idea of being able to isolate the piano better and if necessary, i could add a little bit of effects to give the piano a bit more "natural" sound as it suggested.

i just got a reply back from helpinstill on another topic, but i'll open the dialog regarding yours and my concerns just mentioned and will respond once i have a satisfactory reply.

thanks, mate.

[Dick Rees]

I'm always afraid that folks in your situation will catch sight of such things as these pickup systems.  Not that they're good or bad, but that they are more complex, expensive and problematic than some time tested and relatively simple solutions.  A properly installed Helpenstill system can be fairly nice.  But please note the operative phrase:  properly installed.  There is an art to the installation and such systems require occasional touch-up on the install.

Please answer me this:

Have you tried the SM57 in the hole technique?  You'll get good, usable tone, more than acceptable isolation, simple and forgiving placement and extremely low cost.  It is not a "delicate" setup, either.

If you have not bothered to try this simple solution I strongly recommend that you give it a chance.  It's not fancy, but if you listened to the clip I posted I'm sure you'll have to agree that the sound is as natural as can be.  If you can't get this to work, no amount of fancy and costly pickup is going to suffice.

Good luck.

DR  

[Dick Rees]

Shad Hall wrote on Tue, 26 October 2010 18:41

if necessary, i could add a little bit of effects to give the piano a bit more "natural" sound as it suggested.

No.  Adding effects will just sound like a pickup with effects added.  It will not restore the natural sounds and interactions of strings and soundboard missing from the transducer signal.  Beware of advertising hype.

[Shad Hall]

hi dick,

at the moment i'm using a condenser mic in the middle hole of the sound board (slightly below the surface of the soundboard).

by the way, i have looked for that sound clip you posted, but can't seem to find it. have i lost my mind? (don't answer that. haha j/k) i remember you saying you were going to post it.

thanks for your follow up commentary in the previous two posts.

[Dick Rees]

Shad....

Did you try the SM57?

Did you try different holes and compare the tonal results?

I do not recommend a condenser for this application.

[ProSoundWeb Community]