sound newb questions

[Dreadpoet]

I feel that I am getting closer to understanding sound at my level but I have come up with a list of questions that I commonly run into. I have looked these questions up and feel that while there are comments that could answer these questions...somehow they don't for me. If you care to take a crack at answering my quandries, I would appreciate it.

1) What problems might arise from running 6 wireless mics through a compressor or a reverb unit as a group? I recognize that the compression will only affect the strongest signal on stage at the time, but will it hurt quality or will the reverb unit hurt quality? I can’t afford good compression and reverb for all mics individually currently.

2) When to use TRS and when to use XLR…and what’s the point of TS to begin with other than expense? Mostly I’m curious about plugging in my Shure slx4’s but is there a major difference between balanced TRS and XLR cables?

3) In setting console gain I usual hear to add gain until the signal is around 0 or (unity) on the meter but then usually the very next thing that is said is to adjust it until it sounds correct (volume) on the fader at….0? What am I to make of that? Do I set gain to signal unity or is fader unity…and which of these is a better way of setting mix gain?

4) I have heard only of when to engage the HPF but never of when it is beneficial to disengage…when should I turn HPF on, when off?

5) What is the best way to set sweep eq…turn the eq up and then sweep until you find bad sound and then turn the eq down? Or do I have that backward?

6) Sometimes when I set the factory default gain on the body mic to “mic”(shure slx4) I get an unpleasant sound….is this a problem at the console or at the mic pack or placement? How should I set gain on the mic itself when there is no clear factory default but a slider or wheel of sometype?

[museav]

I'll be interested to see some of the responses!

[gpforet]

1. It is often acceptable to send groups to an effects send for reverb and other effects. Additionally, I have used a single compressor on groups as well. The act of routing in this manner would not, in and of itself affect the quality of the signal.

2. TRS and XLR are both used to carry a balanced signal, typically which helps reject electrical interference. Most XLR connections allow for a positive lock, helping to insure against inadvertant disconnection, whereas TRS can be pulled out quite easily. Signal-wise they are the same.

3. I'm old school so I prefer to set the gain structure starting at the input, and use the gain (trim) to get 0db when pfling the channel. That way I know when level of signal I'm sending to aux and other side-chain buses. I then mix using the faders. Others will say different.

4. HPF is used typically to reject unwanted or un-needed low frequency content in the source. Most will agree that HPF is beneficial when used on vocals, guitars, drum overheads, and other instruments will little usable low frequency content. The only sources where I disengage HPF are kick, piano, and bass.

5. I'd have to listen and identify what it is I'm not liking, and likely solo each source thru headphones until I find the offender, and then set the freq. close to where I think it is, and then cut slowly until I hear the effect, then fine tune frequency (and slope), then finally remove the cans and fine-tune further so the adjustment works within the mix.

6. Assuming you're using the slx1 transmitters, when using "body mics", you'd typically set the transmitter to "microphone". You may be experiencing clothing noise, or other handling noise coming from the mic itself. On the receiver end (slx4), you have both mic level out (XLR), and line level out (TS). The console should be trimmed (gain adjustment) to prevent console input clipping.

1) What problems might arise from running 6 wireless mics through a compressor or a reverb unit as a group? I recognize that the compression will only affect the strongest signal on stage at the time, but will it hurt quality or will the reverb unit hurt quality? I can’t afford good compression and reverb for all mics individually currently.

2) When to use TRS and when to use XLR…and what’s the point of TS to begin with other than expense? Mostly I’m curious about plugging in my Shure slx4’s but is there a major difference between balanced TRS and XLR cables?

3) In setting console gain I usual hear to add gain until the signal is around 0 or (unity) on the meter but then usually the very next thing that is said is to adjust it until it sounds correct (volume) on the fader at….0? What am I to make of that? Do I set gain to signal unity or is fader unity…and which of these is a better way of setting mix gain?

4) I have heard only of when to engage the HPF but never of when it is beneficial to disengage…when should I turn HPF on, when off?

5) What is the best way to set sweep eq…turn the eq up and then sweep until you find bad sound and then turn the eq down? Or do I have that backward?

6) Sometimes when I set the factory default gain on the body mic to “mic”(shure slx4) I get an unpleasant sound….is this a problem at the console or at the mic pack or placement? How should I set gain on the mic itself when there is no clear factory default but a slider or wheel of sometype?

[chausman]

I'll be interested to see some of the responses!

Don't laugh... This is what I was taught. Please correct me if I'm wrong.

1) What problems might arise from running 6 wireless mics through a compressor or a reverb unit as a group? I recognize that the compression will only affect the strongest signal on stage at the time, but will it hurt quality or will the reverb unit hurt quality? I can’t afford good compression and reverb for all mics individually currently.

I would think if you are running 6 Mics through reverb, it wouldn't treat it like 6 different signals with the same effect applied, it would treat it as one noise, and not give you the sound you (or your performers) are looking for. Possibly at a very adverse effect. If needed, only apply the reverb to the Mics who will benefit most from it.

2) When to use TRS and when to use XLR…and what’s the point of TS to begin with other than expense? Mostly I’m curious about plugging in my Shure slx4’s but is there a major difference between balanced TRS and XLR cables?

I would think the difference would be cost and mono verses stereo. I believe there is not a very big difference between TRS and XLR. Three connections, just a different configuration.

3) In setting console gain I usual hear to add gain until the signal is around 0 or (unity) on the meter but then usually the very next thing that is said is to adjust it until it sounds correct (volume) on the fader at….0? What am I to make of that? Do I set gain to signal unity or is fader unity…and which of these is a better way of setting mix gain?

I always set gain to around unity on the meter, then as the show goes on, adjust so the fader is "around" 0. I then use the faders to adjust for differences between scenes or songs or the person using it.[/color]

4) I have heard only of when to engage the HPF but never of when it is beneficial to disengage…when should I turn HPF on, when off?

Are high pass and low cut the same thing?

5) What is the best way to set sweep eq…turn the eq up and then sweep until you find bad sound and then turn the eq down? Or do I have that backward?

I was taught to boost the signal, and then sweep to where it sounds best.

6) Sometimes when I set the factory default gain on the body mic to “mic”(shure slx4) I get an unpleasant sound….is this a problem at the console or at the mic pack or placement? How should I set gain on the mic itself when there is no clear factory default but a slider or wheel of sometype?

I have absolutely no clue...

[MarshallPope]

I don't have much time, but I'll give my answer to a couple of the questions.

1) Personally, I don't like to use compression in the first place, except for certain sopranos who really start to belt once they get into their upper register. If possible, I would only use compression on those individual channels if they really needed it. As for reverb, it really depends on the effect you are going for. By applying it to a group, you will lose a bit of the depth you would have if you used it individually, as the sum of the signals is affected together, rather than having each voice individually bouncing around in the space. If you are using a delay for some specific effect, you would usually want it on the sum rather than have multiple delays going. Again, how you route it really depends on the sound you want

3) I will usually set gain by ear, equalizing each voice to a middle-ish spot on the faders, but usually a bit below unity. That's just my personal preference, and it suits the way I mix. For instruments, this really goes the same way. I will usually mix to unity on the faders by ear. I just like to be able to see when I have something pulled down or pushed up from my "normal," so that's the way I set up my board.

4) I will sometimes turn off the HPF for bass-voiced instruments and occasionally vocals. I will also sometimes turn it off for audio tracks. It really depends on what I am hearing, and if I even think about it. I tend to forget about that little friend.



If I have time, I'll answer further later.

[Dillon]

I'm gonna give you my take... You've got some good questions here.

1) What problems might arise from running 6 wireless mics through a compressor or a reverb unit as a group? I recognize that the compression will only affect the strongest signal on stage at the time, but will it hurt quality or will the reverb unit hurt quality? I can’t afford good compression and reverb for all mics individually currently.
*** When you compress your vocals as a group, any single loud signal will turn down all the members of the group. The compressor will not be doing anything to help maintain even level across all 6 miss. I'd suggest taking that compressor and putting on only on 1 member of the group if you've got a single singer that has too much dynamic range. Don't put it in a place where it can mess up your vocal vs. music balance. On the other side of the coin, you should have no problem feeding a reverb unit from the vocal group -- it's a great way around burning an aux as a reverb send. Keep in mind that the return will include all the vocals in the same mix as the "dry" counterpart.

2) When to use TRS and when to use XLR…and what’s the point of TS to begin with other than expense? Mostly I’m curious about plugging in my Shure slx4’s but is there a major difference between balanced TRS and XLR cables?
*** TRS (and XLR for that matter) are connectors commonly associated with balanced signal cables. I prefer to use XLR whenever possible simply because it is a locking connector and will not pull out at an unfortunate time. TS cables are unbalanced and commonly used only for guitars (before the DI) and used to be more prevelant as speaker drive cables (NL4 is a more common connector for speakers now).

3) In setting console gain I usual hear to add gain until the signal is around 0 or (unity) on the meter but then usually the very next thing that is said is to adjust it until it sounds correct (volume) on the fader at….0? What am I to make of that? Do I set gain to signal unity or is fader unity…and which of these is a better way of setting mix gain?
*** I like to mix my shows with all my inputs' "home" position being 0dB on the fader. I adjust gains accordingly. You have finer control over the level of each input into the main mix (and post-fade auxes) when you're moving the fader in the neighborhood of 0dB than you'd have if you're mixing around the -20dB point on the fader.

4) I have heard only of when to engage the HPF but never of when it is beneficial to disengage…when should I turn HPF on, when off?
*** Look at your console and see if it tells you what frequency is associated with your HPF -- oftentimes it's 80 Hz. Engage it for anything you don't want 80 Hz or less coming through (usually vocals, winds, violins, overheads, etc.) I keep it off for bass, kick, piano, synths, low toms, and other inputs that contribute low-end to the mix.

5) What is the best way to set sweep eq…turn the eq up and then sweep until you find bad sound and then turn the eq down? Or do I have that backward?
*** You're describing a method I use very often. I find it easier to identify bothersome frequencies by first amplifying the filter, sweeping to find the freq, then cutting it back after finding the "nastiest" band. Don't forget to play with your Q if your console has the ability to control the width of the eq filter.

6) Sometimes when I set the factory default gain on the body mic to “mic”(shure slx4) I get an unpleasant sound….is this a problem at the console or at the mic pack or placement? How should I set gain on the mic itself when there is no clear factory default but a slider or wheel of some type?
*** Look at your mic receiver. If you're peaking out the input (often displayed on the front) you'll likely hear distortion and you should then turn down the gain on the pack. The opposite of "mic" inside the pack would be used for connecting the pack to an instrument which would come in hotter than a mic.

[Stookeybrd]

1) What problems might arise from running 6 wireless mics through a compressor or a reverb unit as a group? I recognize that the compression will only affect the strongest signal on stage at the time, but will it hurt quality or will the reverb unit hurt quality? I can’t afford good compression and reverb for all mics individually currently.

Putting multiple mics into a single compressor will only be controlled by the loudest microphone of the bunch. If the signal (multiple now grouped together into one signal) raises above the threshold then the entire signal will be compressed. This will help that one signal that trips the threshold, but will corrode the other signals that stay below the threshold because they will all be compressed.

2) When to use TRS and when to use XLR…and what’s the point of TS to begin with other than expense? Mostly I’m curious about plugging in my Shure slx4’s but is there a major difference between balanced TRS and XLR cables?

XLR and TRS connectors are most commonly used for balanced audio signals. TS is used for either speaker cabling or guitars, and again is a connector. For the Shure units, I would recommend that you use the XLR instead of the TS connection because the balanced cable will be less susceptible to interference and the TS connection is unbalanced.

3) In setting console gain I usual hear to add gain until the signal is around 0 or (unity) on the meter but then usually the very next thing that is said is to adjust it until it sounds correct (volume) on the fader at….0? What am I to make of that? Do I set gain to signal unity or is fader unity…and which of these is a better way of setting mix gain?

Turn your gain all the way down and bring your fader up to "0". Then bring the gain up until the instrument or the singer is at the volume they will sit best in the mix with. At "0" the mixer has more delicate and accurate control over the level of that channel. Many times faders are not perfectly liner and moving the fader an inch above, say "-20", and an inch below will not be the same magnitude of volume change. At "0" an inch above and below will be the same amount of volume change. This is easier to mix night-to-night if singers are louder or quieter than normal because I know exactly where they should normally be and can adjust from there.

4) I have heard only of when to engage the HPF but never of when it is beneficial to disengage…when should I turn HPF on, when off?

HPF filter should be disengaged for anything that creates sound below that set value. Most common inputs would be piano, kick drum, toms, bass, synth, certain male singers(depending), sound effects playback.

5) What is the best way to set sweep eq…turn the eq up and then sweep until you find bad sound and then turn the eq down? Or do I have that backward?

That is the method I use to make a cut that I cannot instantly identify. After finding the offending frequency I like to dial down the gain of the EQ until I like the sound again.

6) Sometimes when I set the factory default gain on the body mic to “mic”(shure slx4) I get an unpleasant sound….is this a problem at the console or at the mic pack or placement? How should I set gain on the mic itself when there is no clear factory default but a slider or wheel of sometype?

The SLX4 have the ability to have an instrument or a microphone as an input to the transmitter. If you are using a lav or body mic the transmitter should always be set to "mic", a guitar with a passive pick-up should use the "0" mark and guitars with active pick-ups should use the "-10" setting. Can you better describe what you mean by unpleasant? Does it crackle, does the sound get really squished when the singer is loud, does it hiss, etc.?

[bishopthomas]

As you have noticed, some people mix on the faders, some on the gain. I feel that mixing on the preamps is "wrong" and it annoys me when I see someone doing the yard stick fader push. Gain structure is important. If you don't get it right at the preamp then how do you expect it to be optimal all the way through the signal path. The logarithmic function of the fader is always given as an excuse (and I understand why), but to keep the fader close to 0 pull down your master fader if you have "too much" headroom or get better amps/speakers if you don't have enough.

[chausman]

I feel that mixing on the preamps is "wrong" and it annoys me when I see someone doing the yard stick fader push

"Yard stick fader push"? Whats that mean?

[cpf]

"Yard stick fader push"? Whats that mean?

I've never heard the term before, but I assume it refers to setting levels using the gain, then using the attenuation slider as a fancy mute switch?

[museav]

"Yard stick fader push"? Whats that mean?

Think using a yardstick to line up all the faders and push them all up to some level, an exact straight line across.

I agree that mixing with the gains is less than ideal, if nothing else it defeats the purpose of pre-fader versus post-fader operation for auxes, effect sends, etc. I also personally fall somewhere between the faders at 0 and input at 0 camps and feel the goal is to find the most effective combination for each source and situation. There are some technical advantages to having gain levels around 0 and typically some operational advantages to having the faders around 0, however it makes no sense to me to have to run a fader very low just so you can get 0 for the input level or to run the input very low or high just to get the fader at 0. Find the reasonable combination that works best for that specific source and the control needed during mixing.

Another aspect to consider is bus summing. Whenever you have multiple inputs with common or similar audio that are summed the resulting summed level is greater than the any individual input level. That means that the level on any bus (aux, group, main, effects, etc.) is typically greater than for any individual input. What makes this more insidious is that the metering for those buses is typically after any master gain or level controls. It's easy to turn down the level, see XdB on the meter and assume that is the level on the bus when it is really not, it is that level in addition to any attenuation or gain applied by the bus master level control. So if you see 0dB but have 12dB of attenuation applied then the level on that bus, and the level hitting the summing amp and other electronics before the bus master level control, is actually +12dB. A similar issue can occur if you do something like assign an input to multiple Groups and then route all of those Groups to the same main bus. One approach to address this when you know you have inputs that will sum in such a manner is to intentionally run those inputs lower so that rather than each input being at 0, the sum of them is at 0.

I should note that these comments apply to analog consoles, digital consoles can be a bit different as there is often an analog gain before the A/D conversion followed by a digital gain after the A/D. In addition, the faders are affecting the digital signal level and some consoles automatically compensate for multi-busing.

[Dreadpoet]

can I assume then that running a volcal group through a single compressor might only be okay if there is only one person singing at a time throughout the show...I realize that this is a dumb question as we would be hard pressed to find a production or live performance that would meet this scenario, but humour me?


Additionally, how do we set the bodypack gain when there is no clear indication of faculty default (actor/performer vocals). I currently have some Mipro mics that have a wheel to set...do I just run them all the way up and worry about signal countrol at the console?

[chausman]

can I assume then that running a volcal group through a single compressor might only be okay if there is only one person singing at a time throughout the show...I realize that this is a dumb question as we would be hard pressed to find a production or live performance that would meet this scenario, but humour me?

I would think that would be fine. It wont know or care if it is getting 8 Mics, and only one is "producing" sound, or getting one mic "making" one sound.

[BGW]

I'd just be repeating what everyone above has said, but I'd like to add one little tidbit I didn't see up there. There's one key difference between TRS and XLR connectors. XLR connectors are a non-shorting variety whereas the TRS connectors are. When you insert a TRS plug into a jack, both parts of the signal are temporarily shorted to ground. While it's always a horrible idea to make interconnections with live equipment, the XLR connectors are a little more forgiving because they don't short and the ground pin is the first to make contact (other than the shield of course) and the last to break it. Making connections with live equipment and TRS/TS connectors usually ends in catastrophe. (Again, not that it's a good thing to do under any circumstances)

Some high quality cables have a separate ground and shield. XLR connectors allow them to be connected to equipment separately while the TRS ones don't. This isn't an issue normally, but sometimes it can help with ground loops.

[nd925a]

Additionally, how do we set the bodypack gain when there is no clear indication of faculty default (actor/performer vocals). I currently have some Mipro mics that have a wheel to set...do I just run them all the way up and worry about signal countrol at the console?

Others please correct me if I'm wrong: start with it run up, and at the receiver watch for clippage and adjust until the signal is at a workable level.

As far as your other questions go the wise people of CB have already answered your questions far better than I ever could.