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What Do You Want to Know About Live Sound But Are Too Afraid To Ask? Dynamic Microphones
Old 4th March 2014
  #31
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Having designed both live and recording boards, put the faders wherever you want. It was my job to make the console work well no matter how you want to use it. That said don't ignore the channel overload LEDs.


=====

Re: Solo or Solo in place, this is a "live Sound" forum and the facility generally used in Live Sound consoles is called PFL (pre fader listen) and like it sounds not destructive to the output mix and grabbing signal pre channel fader.

JR
Old 4th March 2014
  #32
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Quote:
Originally Posted by JohnRoberts View Post


Re: Solo or Solo in place, this is a "live Sound" forum and the facility generally used in Live Sound consoles is called PFL (pre fader listen) and like it sounds not destructive to the output mix and grabbing signal pre channel fader.

JR
Many live consoles support either "cue mode" solo or "destructive solo" almost all Yamahas and Midas for example. In preferences.
Old 4th March 2014
  #33
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Quote:
Originally Posted by museAV View Post
At least in my mind a couple of reasons. One is keeping the channel faders in the most useful or effective positions. If setting the preamp gain to get a certain level and then adjusting the fader for the desired level ends up with a fader near the top of its travel or down where a small movement makes a big change then that can limit the effective use of that fader. So I may not set all faders to nominal 0, but I do want to try to have the faders where I can make finer adjustments and also where I have sufficient range to make the changes that I think I'll need for the mix (e.g. sufficient range to raise a source level as required for a solo).

I also agree with monocluster, the self noise or noise floor of most live sound microphones and other sources is typically greater than the noise floor of the mixer inputs so why boost the source noise at the preamp only to then attenuate the signal at the faders and sends? It seems like the greatest dynamic range with real world live sound sources would be achieved by not amplifying the signal any more than necessary at the preamp.
Your first reason is very unlikely to happen if you brought enough rig for the gig. If the channel faders are averaging near minimum for a comfortable listening level, affecting your ability to make subtle changes, you can always pull down the main faders, or turn down the power amps. If the channel faders are averaging near maximum, and you set the head amps properly, either your master fader is too low, or your power amps are too low, or you didn't bring enough power for the job. In none of those cases will you get a benefit by turning up the head amps more; all you'll do is start clipping the inputs.

Yes, self-noise of the sources is typically higher than the mixer itself, but remember three things; first, by boosting and then attenuating signal strength, you boost and then cut noise along with desired signal, producing no net difference in SNR. Compare that to taking a weak input and having to boost it incrementally in various downstream stages; each of those boosts will amplify the noise floor of everything upstream. Second, in cases where the noise floor of the input is likely to be a problem, you're usually dealing with an upstream gain stage, and if you have one of those, that's where you should be boosting the signal to maximize SNR, not the mixer; the mixer's head amp should be set to unity in such cases. Lastly, every gain stage on the board will be amplifying and reattenuating the signal no matter where the gain control is set; that's how gain stages work. An op-amp boosts the signal by a predefined maximum amount, then a potentiometer either reattenuates the output or varies the amount of signal going to the negative feedback input of the op-amp to control the gain boost directly. All of these stages will introduce a non-negligible amount of noise, which is then attenuated along with the input signal. Maxing downstream gain stages to boost a weak input signal is how you raise the noise floor to audible noise levels.

The cleanest sound, IMHO, comes from boosting the signal as much as you can as far upstream as you can, while retaining headroom. From there, you attenuate the minimum number of times, usually once at the channel fader, to make the source sit in the mix, then from there you shouldn't have to attenuate further if the power amps are set to produce the appropriate SPL through the system for the venue and type of event. Done properly, many of the faders of your final mix will be up in the -20 to 0 range anyway; vocals, keys, anything being DIed or otherwise insufficient to carry the house from the stage, etc etc.
Old 4th March 2014
  #34
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Quote:
Originally Posted by Liko View Post
Your first reason is very unlikely to happen if you brought enough rig for the gig. If the channel faders are averaging near minimum for a comfortable listening level, affecting your ability to make subtle changes, you can always pull down the main faders, or turn down the power amps. If the channel faders are averaging near maximum, and you set the head amps properly, either your master fader is too low, or your power amps are too low, or you didn't bring enough power for the job. In none of those cases will you get a benefit by turning up the head amps more; all you'll do is start clipping the inputs.
Yes.

Quote:
The cleanest sound, IMHO, comes from boosting the signal as much as you can as far upstream as you can, while retaining headroom. From there, you attenuate the minimum number of times, usually once at the channel fader, to make the source sit in the mix, then from there you shouldn't have to attenuate further if the power amps are set to produce the appropriate SPL through the system for the venue and type of event. Done properly, many of the faders of your final mix will be up in the -20 to 0 range anyway; vocals, keys, anything being DIed or otherwise insufficient to carry the house from the stage, etc etc.
Yes again.
Old 4th March 2014
  #35
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edva's Avatar
Quote:
Originally Posted by Liko View Post
The cleanest sound, IMHO, comes from boosting the signal as much as you can as far upstream as you can, while retaining headroom. From there, you attenuate the minimum number of times, usually once at the channel fader, to make the source sit in the mix, then from there you shouldn't have to attenuate further if the power amps are set to produce the appropriate SPL through the system for the venue and type of event. Done properly, many of the faders of your final mix will be up in the -20 to 0 range anyway; vocals, keys, anything being DIed or otherwise insufficient to carry the house from the stage, etc etc.
Yes, but, often you do not have the degree of control over the source (musician) to precisely set gain. And typically, the issue is not too little gain at the source, but too much, as in an increase in volume from soundcheck to show.
In such a scenario, which is very common, it can be less problematic to have a low-gain, high-fader initial setting, for several reasons, which are commonly known, especially with digital equipment.
Additionally, louder sources that are loud enough to be acoustically present in the house present a very high signal-to-noise ratio at the mic. So a low gain setting on the console is even less of a concern with loud sources, in actual practice.
Once the show starts, of course faders are pushed up and down. Gain can also be fine tuned. But starting faders at or near unity is a good thing, IMHO. To each his/her own though.
Old 4th March 2014
  #36
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Is this really a source of concern in a modern console? as long as you're not saturating or sitting too low in pre it should be easy to maintain good gain staging through the console.
Old 4th March 2014
  #37
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Quote:
Originally Posted by Samc View Post
Is this really a source of concern in a modern console? as long as you're not saturating or sitting too low in pre it should be easy to maintain good gain staging through the console.
Path noise inside consoles has not been a major concern for a couple of decades, and then mainly for very large channel counts. FWIW modern digital desks do not have the bus noise gain component that affects analog designs, so yet one less thing to worry about in modern consoles.

I even designed one small mixer to be a little more user-proof , where I calibrated the channel fader to indicate +10dB of post fader gain, but actually operated it at unity gain when full up... with the 10 dB of gain actually located post the summing amp. This way as long as you didn't clip the channel front end you were unlikely to clip the console anywhere else before clipping at the very output. While I would not do this in a large format console with several tens of inputs, for a small mixer the noise floor increase was inconsequential.

Back in the bad old days juggling operating levels and hitting the bus hard was useful to realize a decent S/N. Modern electronics have gotten so much better that it is a lot easier to mix on them now and get a decent result.

Do not kill too many brain cells over-thinking this. Design engineers have invested their effort precisely so products will accommodate a multitude of mixing approaches. Faders are made adjustable, so you can move them where you want. If the output sounds bad or your clip lights look like a Tijuana taxi cab, move them somewhere else.

JR
Old 4th March 2014
  #38
KEL
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a bit of board tape over the clip lights cleans things up nicely
Old 4th March 2014
  #39
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Quote:
Originally Posted by Liko View Post
Your first reason is very unlikely to happen if you brought enough rig for the gig. If the channel faders are averaging near minimum for a comfortable listening level, affecting your ability to make subtle changes, you can always pull down the main faders, or turn down the power amps. If the channel faders are averaging near maximum, and you set the head amps properly, either your master fader is too low, or your power amps are too low, or you didn't bring enough power for the job. In none of those cases will you get a benefit by turning up the head amps more; all you'll do is start clipping the inputs.
Maybe some misunderstanding as 'enough rig for the gig' is irrelevant to what I was addressing. I'm not talking about all channels having the faders too low, but rather where individual channel faders end up as set for the mix. The signal level for a channel going to the mix bus(es) is a combination of the preamp level and the fader attenuation and if you set the preamp to get a certain level then that determines the fader location to obtain a given channel signal level. If that forces the fader to a less effective location then I would rather put the fader where I want it and adjust the preamp to get the desired level for the channel. No difference in output level for that channel or for anything downstream of that, just in how you set the relative channel preamp and fader settings.

Quote:
Originally Posted by Liko View Post
Yes, self-noise of the sources is typically higher than the mixer itself, but remember three things; first, by boosting and then attenuating signal strength, you boost and then cut noise along with desired signal, producing no net difference in SNR. Compare that to taking a weak input and having to boost it incrementally in various downstream stages; each of those boosts will amplify the noise floor of everything upstream.
This seems to support that either approach would yield the same result as I am not talking about doing anything different downstream or changing the channel signal level to the mix bus(es), only varying the relative preamp and fader settings for a channel.

Quote:
Originally Posted by Liko View Post
Second, in cases where the noise floor of the input is likely to be a problem, you're usually dealing with an upstream gain stage, and if you have one of those, that's where you should be boosting the signal to maximize SNR, not the mixer; the mixer's head amp should be set to unity in such cases.
However that is not relevant to a microphone, amp direct out, etc. going direct in to the console.


The only real argument I see with what I propose is if it results in excessively low signal levels to pre-fader mix buses, but that is rare.
Old 6th March 2014
  #40
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Quote:
Originally Posted by KEL View Post
a bit of board tape over the clip lights cleans things up nicely
And you can roll up some board tape and stuff it in your ears...

I have actually encountered one low end mixer that did not detect for clipping at the post fader gain stage so could be driven into hard clipping there, with no over load LED indication. Sounds like your kind of mixer.

Yes clipping brief narrow transients is not very audible, but there is no real need to run modern paths that hot to squeak out the last dB of S/N.

JR

PS: Many power amps have clip limiters built in, so you can be more casual about headroom. I am only aware of one digital console today that provides a soft clipper in the mic preamp.
Old 6th March 2014
  #41
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The technical ramifications of both types of mixing gain structure are well-argued in the above posts. It, like many other things, comes down to personal preference within the confines of the pros and cons of each approach. Not a "you should do it this way" but "IF you do it this way, this happens" for each, and then you can make an educated decision about what will work.
Old 6th March 2014
  #42
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Quote:
Originally Posted by monocluster View Post
The technical ramifications of both types of mixing gain structure are well-argued in the above posts. It, like many other things, comes down to personal preference within the confines of the pros and cons of each approach. Not a "you should do it this way" but "IF you do it this way, this happens" for each, and then you can make an educated decision about what will work.
Agreed, understand the options and figure out what works best for you in the application involved.

Along the same lines, not all people realize how wide a range 'live sound' encompasses. How you mix a band in a bar may be quite different than how you mix a church service, much less a musical in a theater, yet all are a subset of live sound. The same applies to equipment and systems, different applications may call for different solutions and there is no one 'right' answer for all.
Old 6th March 2014
  #43
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A quick search of various internet forums should show that the topic of gain structure, gain staging or whatever you want to call it, has been discussed ad nauseam. Why is it being discussed in this thread? It hardly seems a subject that anyone is afraid to ask about.

I guess that the subjects that no one dare ask about........
Old 6th March 2014
  #44
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Quote:
Originally Posted by Steve_B View Post
Why is it being discussed in this thread?
because someone asked.
Old 7th March 2014
  #45
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ok

Why don't my mixes sound as good as I want them to?

How do you get it to sound and feel loud, all there nice and rich, you make out all the parts, yet its actually at a reasonable level like 98 - 100 dBA SPL ?

is this relative to the size of the gig - managing spill off the stage / stage is so far away spill is not governing the mix?
Old 7th March 2014
  #46
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Quote:
Originally Posted by Electrolytic View Post
ok

Why don't my mixes sound as good as I want them to?

How do you get it to sound and feel loud, all there nice and rich, you make out all the parts, yet its actually at a reasonable level like 98 - 100 dBA SPL ?

is this relative to the size of the gig - managing spill off the stage / stage is so far away spill is not governing the mix?
I will come back to this when I get home from work and give you a good answer. Responding to remind myself.
Old 7th March 2014
  #47
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Quote:
Originally Posted by monocluster View Post
because someone asked.
Ah! So they weren't afraid to.
Old 7th March 2014
  #48
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Quote:
Originally Posted by Electrolytic View Post
ok

Why don't my mixes sound as good as I want them to?

How do you get it to sound and feel loud, all there nice and rich, you make out all the parts, yet its actually at a reasonable level like 98 - 100 dBA SPL ?

is this relative to the size of the gig - managing spill off the stage / stage is so far away spill is not governing the mix?
100dBA is a little high for my taste, still loud enough to damage hearing of the audience.

Hopefully our mixes never sound as good as we want them to- otherwise we have no reason to keep learning, no?
But I see your point.

To avoid fighting with yourself, start with whatever is already coming off the stage. I turn everything down, bring up just enough bass and kick to round it out, vocals nicely on top, then bring guitars and keyboards in around the lead.
Rather than boost EQ bands desired, it's much better to cut out things that you don't need. This creates more space in the mix for the elements to be louder without fighting ("masking").

On a more technical level, loud stage sources such as drums and guitar amps are usually delayed in the PA so they are coherent as they travel through the audience (kick drum out of the PA might otherwise "beat" the stage-volume kick drum by 25ms on a large stage). This isn't a reason your mix doesn't sound good, but it can make a tight mix tighter.

Try to imagine you're mixing on an old analog console, and each time you want to use an EQ or compressor pretend you'd have to patch a physical unit in. In this digital age it's very tempting to throw processing on everything just because we can. In truth, you should be able to get a workable mix together using nothing but high-pass filters. I high pass EVERYTHING except kick and bass, and I run my subs on an aux. Keeps the low end clean and tight.

Use your ears. Listen to other mixes and deconstruct them.
Basically have a reason for everything you do. Know the sound you want, don't just start turning knobs. If you have some recordings I'd be happy to listen to them and give you some feedback.
Old 7th March 2014
  #49
KEL
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Quote:
Originally Posted by JohnRoberts View Post
And you can roll up some board tape and stuff it in your ears...

I have actually encountered one low end mixer that did not detect for clipping at the post fader gain stage so could be driven into hard clipping there, with no over load LED indication. Sounds like your kind of mixer.

Yes clipping brief narrow transients is not very audible, but there is no real need to run modern paths that hot to squeak out the last dB of S/N.

JR

PS: Many power amps have clip limiters built in, so you can be more casual about headroom. I am only aware of one digital console today that provides a soft clipper in the mic preamp.
it was a joke John
Old 8th March 2014
  #50
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Quote:
Originally Posted by Electrolytic View Post
ok

Why don't my mixes sound as good as I want them to?

How do you get it to sound and feel loud, all there nice and rich, you make out all the parts, yet its actually at a reasonable level like 98 - 100 dBA SPL ?

is this relative to the size of the gig - managing spill off the stage / stage is so far away spill is not governing the mix?
Every time I produce, or hear someone else produce a a really good, powerful live mix there was always a really good band on the stage…because that's where it starts. If the band doesn't sound good and powerful before you push up faders pushing up faders is hardly going to change things. But if the band sounds good you should get a sense of that just by pushing up the faders.

Don't do things as a general rule or just because…that includes high passing inputs, do things because they help you get to where you want to go. If you work methodically you should hear when an action affects the sound negatively and always take the time to LISTEN when you touch something…don't be in a hurry to keep adjusting knobs and faders, listen to how you're affecting the sound and decide where you need to go before moving.

Like most things, it takes experience to master mixing, the more you mix is the better you (should) get at it.
Old 8th March 2014
  #51
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I did a gig last night, sound check was a bit stressful, had to constantly repatch the stage box to get it to fit down 18ch. Promoter kept mediating but didn't have a clue so made it worse.
Anyway the gig went well, I didn't use a single piece of outboard, my thinking I should be able to get a good mix with nothing. the bass player wacked his amp up so had to mute that and mix around it but it was ok. bouncing around 95dBA SPL fast @foh so good sensible level as there wasn't many in.
I tried the faders in a line gain staging and it worked wonders for vocals, no need for excessive gain anymore!
the night started bad but was fine in the end.
its all about confidence in your abilities and staying positive despite anything. Sometimes I doubt myself which I know is really bad, but then I think 'well at least there isn't any feedback'
http://theproaudiofiles.com/confiden...it-all-begins/
Old 8th March 2014
  #52
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Quote:
Originally Posted by KEL View Post
it was a joke John
So was my response... I hope everyone lurking gets all the jokes.

JR
Old 9th March 2014
  #53
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Two questions for you...

I run FOH for a client whom I have had the pleasure of working with for the past 2 years. We keep the show pretty simple and dry due to the fact that we never know what kind of PA we are going to encounter and it works for consistency purposes.

Questions:

1) on an analog console, what is a best practice to have a distorted vocal effect during choruses without unwanted feedback at monitors

2) whats a good trick on having an effect of dbl vocals, also during choruses ?


Thanks !
Old 9th March 2014
  #54
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Quote:
Originally Posted by theledgeofaustin View Post
I run FOH for a client whom I have had the pleasure of working with for the past 2 years. We keep the show pretty simple and dry due to the fact that we never know what kind of PA we are going to encounter and it works for consistency purposes.

Questions:

1) on an analog console, what is a best practice to have a distorted vocal effect during choruses without unwanted feedback at monitors

2) whats a good trick on having an effect of dbl vocals, also during choruses ?


Thanks !
Good questions. I would double patch the vocal channel (with a Y cable on an analog desk), run distortion on one of them, do NOT send it to the monitors, only to FOH. Unmute it for the choruses.

Doubles are commonly done with a chorus effect although I dislike the sound of chorus on vocals. A more subtle way is a stereo pitch shift, maybe ten cents up panned to one side and ten cents down on the other side. Again, do not sent pitch shifted vocals to monitors for obvious reasons.
Hope this helps.
m
Old 9th March 2014
  #55
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"1) on an analog console, what is a best practice to have a distorted vocal effect during choruses without unwanted feedback at monitors"

Analog or digital makes no difference. What's happening is that when you add effects you are adding gain and there's only so much gain you can get before you cross a threshold and create feedback. So to my thinking the best practice would be to set the system with the efx as the max and then you'll just have to settle for less during the cleaner passages.

You'll probably notice a big difference that is proportional to stage size and particularly ceiling height. With a high ceiling you won't have as many problems as you will experience with short ceilings.
Old 9th March 2014
  #56
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Quote:
Originally Posted by Electrolytic View Post
I tried the faders in a line gain staging and it worked wonders for vocals, no need for excessive gain anymore!
Can't think of a single technical reason why this would be...Why do you think the change in method cause this to happen??
Old 9th March 2014
  #57
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I'm not afraid to ask, but I didn't feel like opening a new thread just for a single question...
I'm 14, and I'm really interested in live sound engineering; I spend nearly all day searching about techniques, equipment, and so on, and so far I've learnt LOTS of stuff. Forums have pretty much given answers to most of my questions, except an unusual one...

My question is: Do all (rental) companies offer "Event Organizing" and complete Staging/Lighting/Audio solutions, or are there companies that do Audio only? I live in a small island in Greece, where all "rental" companies are studios with a set of low-end* Line Arrays, an averagely-sized stage, some trussing and par cans so I can't really get an answer...

I'm sort of trying to do my plans for my future. I'd like to move to the UK or some other similar country (With more sun :P), where there would possibly be more demand for an Audio-Only solutions (Dry-Hires, Hiring and mixing, as well as mixing-only) - If there is actually any demand at all.
Depending on the answers, I might have some follow-up questions as well...
Thanks!

low-end*: Low End compared to Vertec, vDosc, and stuff like that. One company that I'm aware of has a dB Technologies DVT4 set (I think 4+4 tops and 4 subs), another one has Martin Audio speakers, and a third one some DIY (Well they look like DIY) Cabs.
Old 10th March 2014
  #58
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Quote:
Originally Posted by Samc View Post
Can't think of a single technical reason why this would be...Why do you think the change in method cause this to happen??
less ringy - there said it

I know where you going with this. gbf, total gain the system is no different and all that

I think no need for excessive noise floor is the case. Dare I say it and I'm more technical than most bare in mind. 'not over inflating the bubble around the mic'. I know that makes no sense as that is not how pre amps work. but I know what your thinking, you can save it samc. It works better, it just does.

the setup has less 'over gaining' in the system to be attenuated back down this is the difference in the method.

if you can deduce what is really going on then shoot.
Old 10th March 2014
  #59
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Is this thread still open to new discussion? If so, I've been researching power amp technology (class d, a/b, b, etc) and it's confusing!

What power amp would you use for a pair of EV elx215's, and why?

I've looked at crown xls, xti, and xli series, qsc doesn't seem to have a good "budget minded" amp that provides 1200 watts/channel at 4 ohm. Also it seems that some class amps actually deliver a larger amount of power to the amp, regardless of rating. SO what the F is the dealio

-edit my latest consideration is 2x xls1500 crown drivecore amps, running 1/speaker bridged for 1350w a unit or 1x crown xli 3500 with 1200 watts a side, also 4 ohms. But sensitivity can be different ?
Old 10th March 2014
  #60
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Quote:
Originally Posted by Steve_B View Post
Ah! So they weren't afraid to.
Either that, or they overcame their fear
Topic:
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