something crossed my mind and i need advice .....
lets suppose you have a small stage with 2 main pa speakers located left and right of the stage just a bit in front of the microphone where the singer is located ....
then ofcourse you have one monitor looking towards the singer
so the voice and the microphone of the singer are almost in phase with the PA speakers ..... but the monitor has a diference of 180 since is located against the pa speakers and the vocalist ...
the question :
if the polarity of the monitor is reversed and actually is "tuned " more in phase compaired to the voice and the PA system
will this have any effect on feedback cancelation ???? will actually create more ???? or less ???? feedback .....
and then again if you have no feedbak issues will the vocalist hear better if the monitors are more in phase with the pa and the voice ????... or not ????
( keep in mind that we talk about a small stage ... in a small club for 150 pax ....meaning that the vocalist will hear from the monitors but also he has a sense from the PA also since its located quiet close to him ...)
all input is very welcome .... thank u very much
lets suppose you have a small stage with 2 main pa speakers located left and right of the stage just a bit in front of the microphone where the singer is located ....
then ofcourse you have one monitor looking towards the singer
so the voice and the microphone of the singer are almost in phase with the PA speakers ..... but the monitor has a diference of 180 since is located against the pa speakers and the vocalist ...
the question :
if the polarity of the monitor is reversed and actually is "tuned " more in phase compaired to the voice and the PA system
will this have any effect on feedback cancelation ???? will actually create more ???? or less ???? feedback .....
and then again if you have no feedbak issues will the vocalist hear better if the monitors are more in phase with the pa and the voice ????... or not ????
( keep in mind that we talk about a small stage ... in a small club for 150 pax ....meaning that the vocalist will hear from the monitors but also he has a sense from the PA also since its located quiet close to him ...)
all input is very welcome .... thank u very much
Yes, and possibly... And that is the reason that many PA systems include a polarity reverse switch, so each mic line can be inverted.
Because each stage is different and the spacing between mics and other mics and sound sources ( including virtual ones from reflections ) can create "interesting" sonic situations, that call for interesting solutions.
Although 2 sources will be 180 degrees out at a particular frequency, at a given distance, they will have other phase relationships ( constructive and destructive ) at other frequencies and spacing.
Syd
Google this phrase:
microphone "polarity reversal"
and you will get a lot of detail on this.
Including:
The Sound Reinforcement Handbook
By Gary Davis, Ralph Jones, Yamaha International Corporation
* available as a limited Google book preview.
see page 186 - Polarity ( Phase ) Reversal
IMO This book is a must have/1st book reference.
Syd
microphone "polarity reversal"
and you will get a lot of detail on this.
Including:
The Sound Reinforcement Handbook
By Gary Davis, Ralph Jones, Yamaha International Corporation
* available as a limited Google book preview.
see page 186 - Polarity ( Phase ) Reversal
IMO This book is a must have/1st book reference.
Syd
Use hypercardioid stage mics...
some people like the DSP based "feedback destroyers".
yes the relationship between the mics and the ambient sources of high level sound will effect feedback.
Better to also do something acoustically (not urethane foam) to control the reverberation levels in your room and on ur stage as well... most "club" rooms are awful acoustically for amplified music...
_-_-bear
some people like the DSP based "feedback destroyers".
yes the relationship between the mics and the ambient sources of high level sound will effect feedback.
Better to also do something acoustically (not urethane foam) to control the reverberation levels in your room and on ur stage as well... most "club" rooms are awful acoustically for amplified music...
_-_-bear
GUYS COME ON !!!!!!!
this is not a question about feedback cancelation .....
also there is no question of reversing pahse in the microphone ....
in a given situation ..... 2 pa speakers left and right just a bit in front of the mike and one monitor towards the vocalist ....
Question remains ::::
will reversing the polarity of the monitor improove the listening conditions of the vovalist ????
the creation or cancelation of more or less feedback is a very secondary issue ....
thanks you ...
this is not a question about feedback cancelation .....
also there is no question of reversing pahse in the microphone ....
in a given situation ..... 2 pa speakers left and right just a bit in front of the mike and one monitor towards the vocalist ....
Question remains ::::
will reversing the polarity of the monitor improove the listening conditions of the vovalist ????
the creation or cancelation of more or less feedback is a very secondary issue ....
thanks you ...
You are not seeing ALL the elements that make up the scenario.
You can flip the polarity of a microphone OR a monitor.
This is one of the reasons why the polarity flip option is provided on monitors and mics: to allow for a possible fix.
Original source ( the vocalist ) + electrically amplified and modified source ( the microphone to monitor chain ) and a small venue with nearby walls, floor, and ceiling surfaces of varying qualities of sound absorption and reflectivity guarantee that the vocalist is going to hear a lot of reflection.
Running simulations of the interactions of 2 sound sources in an enclosed environment ( these allow for the simulation of a polarity flip BTW ), you will observe that it is NOT a panacea.
Polarity flip is just one technique. Subtle adjustment of placement of monitor, vocalist, and microphone can have a large effect on the overall sound, and what the vocalist hears in a small room.
See the above reference for comb filtering: The vocalist gets to hear the sum of direct sound production, an amplified analogue ( ie the monitor ) and the reflections from the surrounding surfaces.
It's a sonic soup and how the monitor interfaces with the room and mic obviously is going to effect what the vocalist hears.
Practically speaking I have better success with placement and EQ vs polarity reversal at any point in the mic to monitor chain.
I found feedback destroyers to be too coarse in their action and ultimately left the sound "dull".
* BTW: Bob McCarthy details the subject of polarity flip in his online work.
** Shouldn't this thread be moved?
You can flip the polarity of a microphone OR a monitor.
Possibly, and again,
This is one of the reasons why the polarity flip option is provided on monitors and mics: to allow for a possible fix.
On the contrary: In a small venue with the real source ( the vocalist ) on a small stage, room acoustics are a huge factor.
Original source ( the vocalist ) + electrically amplified and modified source ( the microphone to monitor chain ) and a small venue with nearby walls, floor, and ceiling surfaces of varying qualities of sound absorption and reflectivity guarantee that the vocalist is going to hear a lot of reflection.
Running simulations of the interactions of 2 sound sources in an enclosed environment ( these allow for the simulation of a polarity flip BTW ), you will observe that it is NOT a panacea.
Polarity flip is just one technique. Subtle adjustment of placement of monitor, vocalist, and microphone can have a large effect on the overall sound, and what the vocalist hears in a small room.
See the above reference for comb filtering: The vocalist gets to hear the sum of direct sound production, an amplified analogue ( ie the monitor ) and the reflections from the surrounding surfaces.
It's a sonic soup and how the monitor interfaces with the room and mic obviously is going to effect what the vocalist hears.
Practically speaking I have better success with placement and EQ vs polarity reversal at any point in the mic to monitor chain.
I found feedback destroyers to be too coarse in their action and ultimately left the sound "dull".
* BTW: Bob McCarthy details the subject of polarity flip in his online work.
** Shouldn't this thread be moved?
ok start to get it
like this doesnt get somewhere ...
this is all too theoretical ....it should be a yes or no thing by someone who tested this or not ....
the thing is that in a small setup like that where only onesound engineer exists and most of the time is spended in fron of the PA and in front of monitors ....then i think that only real life extented tests will show results .....
thanks though
like this doesnt get somewhere ...
this is all too theoretical ....it should be a yes or no thing by someone who tested this or not ....
the thing is that in a small setup like that where only onesound engineer exists and most of the time is spended in fron of the PA and in front of monitors ....then i think that only real life extented tests will show results .....
thanks though
I have and found it necessary ONLY with multiple monitors placed close together, and not necessary or effective for other circumstances.
See this article:
http://mixonline.com/live/applications/audio_understanding_phase/
section PHASE AND POLARITY
You are quite welcome.
When it comes to live sound you have to be willing to improvise and experiment, because every room is different.
Bob McCarthy approach is less math intensive, and very helpful
These articles may also help:
http://mixonline.com/live/applications/audio_equalizing_room/
http://mixonline.com/live/applications/audio_equalizer_inequality/index.html
He has some very helpful videos online and books as well.
http://www.youtube.com/watch?v=5Ig_oRpz3_k
http://www.youtube.com/watch?v=A9098KMP_Q8
http://www.youtube.com/watch?v=C2PGZq5PEe8&
Google also allows for preview of Bob McCarthy's book
http://books.google.com/books?id=w9B2kgjxl4cC&printsec=frontcover
Best of Luck
Syd
When it comes to live sound you have to be willing to improvise and experiment, because every room is different.
Bob McCarthy approach is less math intensive, and very helpful
These articles may also help:
http://mixonline.com/live/applications/audio_equalizing_room/
http://mixonline.com/live/applications/audio_equalizer_inequality/index.html
He has some very helpful videos online and books as well.
http://www.youtube.com/watch?v=5Ig_oRpz3_k
http://www.youtube.com/watch?v=A9098KMP_Q8
http://www.youtube.com/watch?v=C2PGZq5PEe8&
Google also allows for preview of Bob McCarthy's book
http://books.google.com/books?id=w9B2kgjxl4cC&printsec=frontcover
Best of Luck
Syd
Re: ok start to get it
There isn´t and will never be any definitive answer about anything in music, listening, etc.
If reversing the polarity helps, depends on the exact placement of all the three speakers, the reverberetions form the venue, reverberations from the stage (mainly shape and surface of the back wall), where is the singer standing, height of the ceilings, how high the singer is, other band memebers, people in the audience, etc., etc. All these factors affect what the singer hears.
You just have to try it on your stage and see which polarity is better.
The right answer is DEPENDS.sakis said:
There isn´t and will never be any definitive answer about anything in music, listening, etc.
If reversing the polarity helps, depends on the exact placement of all the three speakers, the reverberetions form the venue, reverberations from the stage (mainly shape and surface of the back wall), where is the singer standing, height of the ceilings, how high the singer is, other band memebers, people in the audience, etc., etc. All these factors affect what the singer hears.
You just have to try it on your stage and see which polarity is better.
The monitor in reverse polarity is successful when it is facing a soft surface; however, if the signal strikes a hard surface, the phase is altered and will take some experimentation. So, does your stage have a curtain behind the performers, or not?
Also, time delay from the microphone affects feedback. Not only is it the space between the microphone and the speaker, and the space between reflective surfaces in the microphone, but it is also the very slight delay in the amplification--any one of which is just enough to the make the phase take a bit of experimentation in practice, because that many variable factors aren't easily predictable. This must be done on site.
Also, time delay from the microphone affects feedback. Not only is it the space between the microphone and the speaker, and the space between reflective surfaces in the microphone, but it is also the very slight delay in the amplification--any one of which is just enough to the make the phase take a bit of experimentation in practice, because that many variable factors aren't easily predictable. This must be done on site.
Dude... 
In a live performance situation everything depends on the actual situation.
Let me focus in on one thing I said - control the reverberation levels on the stage and in the room if you want your performers to hear better...
99% of all small club stages are so ******* loud and high in reverberation energy that nothing anyone can do will make a bit of difference, imho.
The definitive answer = "in ear monitors."
Ok now?
_-_-bear
In a live performance situation everything depends on the actual situation.
Let me focus in on one thing I said - control the reverberation levels on the stage and in the room if you want your performers to hear better...
99% of all small club stages are so ******* loud and high in reverberation energy that nothing anyone can do will make a bit of difference, imho.
The definitive answer = "in ear monitors."
Ok now?
_-_-bear
thanks all
for all the detailed answers .....
fotios: infront of the vocalist most of the times .....
the truth is that if somebody ask me the smalest detail about my PA system in this small club i am able to answer
as about the musicians on stage i havent actually spent a lot of time on stage to be able to "translate" their needs ....to audio terms ...
i will construct a box that by pressing a switch will turn phase 180 and then ask them what do thy think is better ...
lets see
for all the detailed answers .....
fotios: infront of the vocalist most of the times .....
the truth is that if somebody ask me the smalest detail about my PA system in this small club i am able to answer
as about the musicians on stage i havent actually spent a lot of time on stage to be able to "translate" their needs ....to audio terms ...
i will construct a box that by pressing a switch will turn phase 180 and then ask them what do thy think is better ...
lets see
Sakis
Because i have spent enough of my life in live stages included SKYLADIKA
, from experience i will say two main things:
1) Some vocalists they prefer to hear a little (be carefull, a little!) the mixdown including their voice from the pa speakers. Some others they preffer to hear only monitors and the sound of band as is. By the chance given, the absolute solution are the side fill monitors which serves only for the whole group and from which heared the same mixdown result as from the foh speakers. Now, for the vocalist, i think the problem - it is a general case - it is not related with phase, reverberation etc. Trick: try to give him some amplification in mid-high frequencies (4KHz are a mid value) from the equalizer of his channel in mixing desk. Also add a small percent of effex echo+reverb yet (this must be pre-fader). Most vocalists they like this combination.
2) Instead to increase the level of monitors (which drives in feedback), ask politely from the band to lower their volume. Keep in mind that, a band without enough practice, they play very loud causing thus an amazing confusion, as the vocalist can't hear his voice from monitors and asks more volume, and so on . A good band, performs very easy. The bass performer must hear very clear the drummer - mainly the kick drum - to synchronized, the drummer the same, as well the keybord performer in some cases. If they can't hear well the one the other, or one of them make mistakes, then the confusion starts.
There are a lot of other things, which i can't writte here because the length.
Feel free to contact with me for further.
Fotios
Because i have spent enough of my life in live stages included SKYLADIKA
, from experience i will say two main things:1) Some vocalists they prefer to hear a little (be carefull, a little!) the mixdown including their voice from the pa speakers. Some others they preffer to hear only monitors and the sound of band as is. By the chance given, the absolute solution are the side fill monitors which serves only for the whole group and from which heared the same mixdown result as from the foh speakers. Now, for the vocalist, i think the problem - it is a general case - it is not related with phase, reverberation etc. Trick: try to give him some amplification in mid-high frequencies (4KHz are a mid value) from the equalizer of his channel in mixing desk. Also add a small percent of effex echo+reverb yet (this must be pre-fader). Most vocalists they like this combination.
2) Instead to increase the level of monitors (which drives in feedback), ask politely from the band to lower their volume. Keep in mind that, a band without enough practice, they play very loud causing thus an amazing confusion, as the vocalist can't hear his voice from monitors and asks more volume, and so on . A good band, performs very easy. The bass performer must hear very clear the drummer - mainly the kick drum - to synchronized, the drummer the same, as well the keybord performer in some cases. If they can't hear well the one the other, or one of them make mistakes, then the confusion starts.
There are a lot of other things, which i can't writte here because the length.
Feel free to contact with me for further.
Fotios
In all of this the specifics of the monitor was not mentioned:
Many monitors are highly directional and "beam", so if the target is not on-axis, little HF is heard. Some monitors have a tailored frequency response to "punch-through" the vocal range; Putting instruments through these can be problematic, If it is not a full range flat response device.
It is pretty much standard practice to cut every thing below 100hz on a vocal mic to eliminate stage thump, vocal pop on percussive notes, and to clean up some of the boom and mud on the low end. To many ears this can sound too thin on it's own, as soon as the FOH is brought up, however it's addition is enough to add perceived fullness to the vocalist ears.
If, as fotios mentioned, there are several vocalists, and EACH requires a separate personalized monitor mix, with the possibility of fold back of instrumentation and FX, Then it becomes much more complicated, perhaps requiring a dedicated monitor system with a powered monitor for every player. ( BTW Currently I am using a Soundcraft Spirit II ).
The other considerations? Size of room, and stage, orientation and sonic details of the stage, Also the band and their equipment.
Monitor mixing can be tough - Personally doing FOH sound is much easier than providing personalized monitor mixes for a half dozen musicians, especially if they can barely fit on a stage surrounded by hard reflective surfaces.
Syd
Many monitors are highly directional and "beam", so if the target is not on-axis, little HF is heard. Some monitors have a tailored frequency response to "punch-through" the vocal range; Putting instruments through these can be problematic, If it is not a full range flat response device.
It is pretty much standard practice to cut every thing below 100hz on a vocal mic to eliminate stage thump, vocal pop on percussive notes, and to clean up some of the boom and mud on the low end. To many ears this can sound too thin on it's own, as soon as the FOH is brought up, however it's addition is enough to add perceived fullness to the vocalist ears.
If, as fotios mentioned, there are several vocalists, and EACH requires a separate personalized monitor mix, with the possibility of fold back of instrumentation and FX, Then it becomes much more complicated, perhaps requiring a dedicated monitor system with a powered monitor for every player. ( BTW Currently I am using a Soundcraft Spirit II ).
The other considerations? Size of room, and stage, orientation and sonic details of the stage, Also the band and their equipment.
Monitor mixing can be tough - Personally doing FOH sound is much easier than providing personalized monitor mixes for a half dozen musicians, especially if they can barely fit on a stage surrounded by hard reflective surfaces.
Syd
ok ok .....lets see
my shelf also been spending a hell of a lot of time in small or medioum PA systems ..... most of it has been live greek music or live rock music ...rearlly some DJ sets where set ups are so easy ...let us not forget that i am the owner of my company and of course rentals is a big part of it ......
in the small comunity i work you may listen a lot of good comments about my work but the one that stands on the the top ... is that "when sakis is working the PA system then the music can be really very loud with no feedback at all and maintain some quality"
my company runs about 150 events a year all small to medium size for audience to 100- 1500 people .....
more than half of these shows are operated by me and my tactik about this is to first make the stage people happy provide them enything they need regarding ammounts of power, effects, extra monitors and so on and after these people are satisfieyd then take their product adjust it to the room or area and give it to the public after filtering it with my personal touch....
( small example is that once i had to consume 2 diferent effect units to provide the drummer with what he wanted in the monitors and one other effect unit that i found suitable for the pa the music and audience )
I never face feedback problems in my setups even though i run quite highly powered monitors 500W/monitor or so cause after so many years of expirience i know what monitor goes were which microphone to which instrument or vocalist and so on ..... except knowledge this also a mater of expirience or good practice ....since i have the privilige to work with people i know most of the times cause they like my work and stick close to me ....
this all question is tactics in order if possible to improove or optimise an allready working thing ..... could just as well leave it as is .... but i would be very curious to see the diference ....
regards sakis
my shelf also been spending a hell of a lot of time in small or medioum PA systems ..... most of it has been live greek music or live rock music ...rearlly some DJ sets where set ups are so easy ...let us not forget that i am the owner of my company and of course rentals is a big part of it ......
in the small comunity i work you may listen a lot of good comments about my work but the one that stands on the the top ... is that "when sakis is working the PA system then the music can be really very loud with no feedback at all and maintain some quality"
my company runs about 150 events a year all small to medium size for audience to 100- 1500 people .....
more than half of these shows are operated by me and my tactik about this is to first make the stage people happy provide them enything they need regarding ammounts of power, effects, extra monitors and so on and after these people are satisfieyd then take their product adjust it to the room or area and give it to the public after filtering it with my personal touch....
( small example is that once i had to consume 2 diferent effect units to provide the drummer with what he wanted in the monitors and one other effect unit that i found suitable for the pa the music and audience )
I never face feedback problems in my setups even though i run quite highly powered monitors 500W/monitor or so cause after so many years of expirience i know what monitor goes were which microphone to which instrument or vocalist and so on ..... except knowledge this also a mater of expirience or good practice ....since i have the privilige to work with people i know most of the times cause they like my work and stick close to me ....
this all question is tactics in order if possible to improove or optimise an allready working thing ..... could just as well leave it as is .... but i would be very curious to see the diference ....
regards sakis
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