Post by: Aaron McQueen on September 30, 2009, 03:42:06 PM
We went back to his Lavaliere he had before this which is a Shure WL184 (supercardioid). This mic doesn't sound great to me and because of it's tight pattern, movement is problematic, and there is quite a few plosives even with a pretty high HPF.
So I picked up a Countryman B6 (omni) thinking it would be better. And it is sound wise, but I'm struggling with feedback. I just can't seem to get the gain I need without feedback. It get's worse when he stands in front of the lectern or any boundary. I'm constantly riding the fader. I consider myself to be halfway decent at pulling out the offending frequencies, but pretty quickly I'm pulling out too much. The board is a LS9, which usually provides enough eq on the channel. I guess I could insert one of the 31-band eqs if needed. If someone less experienced is running sound it gets out of hand quickly, and I have make a run to the booth to help out.
What's my next step? Any help is appreciated.
Post by: Dick Rees on September 30, 2009, 04:14:38 PM
You could try one of the single channel "Solo" FBX units from Sabine in line on his mic. In analog world I use the insertable model. This will add 5 parametric filters and leave you a 6th
"rover" which will stand by. That combined with the onboard parametric and shelving filters should give you a bit more control.
Post by: John Fiorello on September 30, 2009, 06:58:39 PM
What freq. is it feeding back at?
And what cap do you have on it?
I only ask because if it's feeding back somewhere above 5k, the 0dB cap might help...?
JF
Post by: Tom Young on September 30, 2009, 09:58:56 PM
What is the physical relationship of the FOH ldspkrs to the position(s) he stands in ?
How "linear" is the FOH system (has it been optimized properly) ?
Finally: I pray the feedback is from FOH and NOT because you have him in monitors (for himself to hear).
Post by: Gil Parente on October 01, 2009, 12:55:22 AM
That is what I would start with.
Post by: Brian Ehlers on October 01, 2009, 07:28:22 PM
Here's something else to consider and try:
One of the nice things about omni lavs is that you don't have to mount them on the orator's chest (tie, shirt, lapel). Try mounting it on his shoulder by clipping it to the collar. Just make sure his chin doesn't rub against it when he turns his head. Broadway shows get creative and mount lavs in hairpieces or hats, though that's probably not an option for you.
There's two reasons I'm suggesting higher placement. First, the closer you get the mic to the source (his mouth), the more you can turn down the gain, and thus reduce feedback. Second, you mentioned that the feedback is worse when he's standing at the lectern. This is common, and it's caused by sound from your loudspeakers reflecting off the lectern. The further you get the mic from the lectern, the less reflected sound it will pick up.
Finally, don't be shy with your board's EQ. Most lavs can use BIG cuts at about 600 - 800 Hz and of course down in the low frequencies. Play with this; you might find it not only sounds more natural but also eliminates the feedback.
I share your dislike for directional lavaliers. I used them for years but finally got sick of the handling noise, plosives, and the proximity effect every time the orator looks down.
Post by: Aaron McQueen on October 01, 2009, 08:58:48 PM
| John Fiorello wrote on Wed, 30 September 2009 18:58 |
2 questions: What freq. is it feeding back at? And what cap do you have on it? I only ask because if it's feeding back somewhere above 5k, the 0dB cap might help...? JF |
There is not a single offending frequency. I've used all of the available channel eq on the LS9 trying to grab as many frequencies as possible.
I have the 0dB cap on. It's plenty crisp. The problem doesn't seem to be that high.
Post by: Aaron McQueen on October 01, 2009, 09:08:46 PM
| Tom Young wrote on Wed, 30 September 2009 21:58 |
What is the FOH loudspeaker system design ? What is the physical relationship of the FOH ldspkrs to the position(s) he stands in ? How "linear" is the FOH system (has it been optimized properly) ? Finally: I pray the feedback is from FOH and NOT because you have him in monitors (for himself to hear). |
The FOH system is a bi-amped JBL 3 speaker cluster flown center front of stage. There is very little sound in the area the pastor usually stands and moves around in.
The linearity of system is something to look at and it has not been optimized in several years (at least 10).
Definitely no monitors.
Post by: Aaron McQueen on October 01, 2009, 09:13:27 PM
| Gil Parente wrote on Thu, 01 October 2009 00:55 |
Without knowing more details, as Tom mentioned, your idea of the 1/3 octave EQ patched on the channel is not the worst I've heard. That is what I would start with. |
I think I can try this on the LS9 without additional equipment.
Post by: Dick Rees on October 01, 2009, 09:22:08 PM
| Aaron McQueen wrote on Thu, 01 October 2009 21:08 | ||
The FOH system is a bi-amped JBL 3 speaker cluster flown center front of stage. There is very little sound in the area the pastor usually stands and moves around in. The linearity of system is something to look at and it has not been optimized in several years (at least 10). Definitely no monitors. |
There will be an inaudible or barely audible lobe underneath a center cluster arrangement, most often in the low mid range anywhere from 100 to 400. This can be very problematic.
Despite the EQ available on your console, this sounds to me like an overall system/deployment issue which needs to be dealt with before working on the individual channel. If I were there I'd very carefully "ring out" the room using a number of parametric filters applied as needed over the entire spectrum. This is most often done these days (it seems) in the system or amplifier DSP.
Beyond that, I still would go with an automatic parametric device (more commonly known as FBX) of your choice on the input to the LS9 IF you find that the system-wide calibration does not allow you to deal with the problem with the on-board channel EQ. It's even odds, I'd bet.
As I said before, I carry the Sabine Solo FBX units with me for troubleshooting problems such as this. In some cases the units stay in place permanently.
Post by: Wes Thompson on October 03, 2009, 08:34:22 AM
If you have the funding available, I would recommend a higher quality unit of course. For 99 dollars the Behringer works quite well and we were pleasantly surprised by its performance.
-Wes
Post by: Dick Rees on October 03, 2009, 11:41:46 AM
For the filters to remain stable once set you MUST switch them to parametric mode (PA). Leaving them in single-shot (SI) mode WILL allow them to deepen and widen, eating program and thinning out the sound. Unfortunately these must be switched per filter as there is no global way to lock them down as with the Sabine units.
I do like these (B******) units and use them on monitor duty when I end up there for a festival. I do set up all ten available program memories in identical configs so I can simply switch to the next one without wiping the one I've just set up. The filters are OK and if you know how to use one, they can be very good. It's just that they are labor intensive with a bit of a steep learning curve.
The best solution although not the cheapest is the full-fledged Sabine GraphiQ. With this unit you can do the whole system and the ability to see everything on a laptop is quite helpful. Short of that, the Sabine Solo unit walks all over the Behringer. I have and use both and that is my take on them: both good, Sabine better.
Post by: Wes Thompson on October 05, 2009, 09:05:51 AM
So you say that the blocked frequencies will deepen and widen in single shot mode? I never knew that. So once the single shot filter is isolated do I just simply switch that filter over to parametric mode after that?
Do the filters deepen and widen constantly or is this unit effectively storing the deeper and wider settings? In other words, when I power the unit up do the notches come up with the deeper and wider settings or do they come up with the original notch?
The reason I ask, every now and then the vocals can sound like they are in a tunnel. I can switch to another preset and then back and it is fine after that. I figured that it is the auto filters that are causing this problem.
Do I have to re-ring the system for the offending frequencies again or can I simply switch the current single shot filters to parametric mode right after I turn the unit on?
Should I turn off the auto filters? I don't think they are helping anyway since I will lower the channel gain faster than the FB will detect a ring anyway.
This unit has done wonders for improving the performance of our lavs.
Thanks,
Wes
Post by: Dick Rees on October 05, 2009, 10:19:43 AM
| Wes Thompson wrote on Mon, 05 October 2009 09:05 |
I have a question for you Dick, but it does relate to this thread so I will keep it here. So you say that the blocked frequencies will deepen and widen in single shot mode? I never knew that. So once the single shot filter is isolated do I just simply switch that filter over to parametric mode after that? |
That has been my experience. Both the automatic (AU) and single-shot (SI) filters tend to "creep". They keep analyzing the spectrum and adjusting themselves ad infinitum. To be safe, just select the filters (one at a time since there is no global control) once they have identified a "hot" frequency and switch them to parametric (PA). You can get pretty fast at this. You can go back in and widen the filters manually (or deepen them) as needed once you've designated them as parametric. FYI, there is a chart in the manual which will give you very specific frequency readings in +/- fashion from the default frequency centers. For the skilled user this can be extremely handy in sonic micro-surgery.
| Quote: |
Do the filters deepen and widen constantly or is this unit effectively storing the deeper and wider settings? In other words, when I power the unit up do the notches come up with the deeper and wider settings or do they come up with the original notch? The reason I ask, every now and then the vocals can sound like they are in a tunnel. I can switch to another preset and then back and it is fine after that. I figured that it is the auto filters that are causing this problem. |
You are correct, sir. The changes will be permanent and do not require pressing the "Store" button. You will be stuck with them.
| Quote: |
Do I have to re-ring the system for the offending frequencies again or can I simply switch the current single shot filters to parametric mode right after I turn the unit on? |
If you've charted the initial settings after ringing out, you could switch to PA and then restore them by hand. Otherwise it's back to square one.
[qoute]Should I turn off the auto filters? I don't think they are helping anyway since I will lower the channel gain faster than the FB will detect a ring anyway.
This unit has done wonders for improving the performance of our lavs.
Thanks,
Wes[/quote]
I take it that you have left some previously unused filters lurking around in AU mode. Typically, I'll set one of these units up with 5-7 filters set and locked down in PA mode, then turn off all but two of the remaining filters. Those two I leave in AU mode as roving "safeties". They will help catch transients, replace each other as needed and not generally yield the "cannibalistic" traits of a mass of AU or SI filters.
Yes, these units can function very, very well. It took me a good while to come to the level of understanding necessary to utilize them fully. Now that I do "grok" them fully, they can be very good.
Good luck.
DR
Post by: Wes Thompson on October 05, 2009, 12:47:56 PM
Feedback has been a constant struggle in our VERY live room and this unit has helped us tremendously in squeezing out more gain from the lavs.
The following is to add information on my feedback solution to this thread:
Have some helpers wear the lavs. Run up the gain on each lav and use the parametric EQ on the mixer board to null out the main ring from each mic. Once you have achieved max gain with minimal ringing from each lav engage the FB with each filter in single shot mode and slowly raise the gain until you get a ring and a filter locks in on the ring. As soon as the filter locks in, switch it to parametric mode. Once the gain is nice and strong have the lav helpers move around the speaking areas and see if the FB can lock on any more rings. Once most of the rings are filtered, leave only two channels set on auto mode and they can alternate to catch any transients.
One thing to note for anyone using one of these, it is important to have as close to 0db going through this unit as you can get without overdriving it. It detects rings much better when you have a lot of gain going through it.
Thanks again Dick for giving me a better understanding of how to operate this unit.
-Wes
Post by: Dick Rees on October 05, 2009, 01:17:10 PM
| Wes Thompson wrote on Mon, 05 October 2009 12:47 |
Excellent advice Dick. I will re-ring the lavs and set the filters to parametric. It is a pain to set up but once it is done it should be "set and forget". Feedback has been a constant struggle in our VERY live room and this unit has helped us tremendously in squeezing out more gain from the lavs. The following is to add information on my feedback solution to this thread: Have some helpers wear the lavs. Run up the gain on each lav and use the parametric EQ on the mixer board to null out the main ring from each mic. Once you have achieved max gain with minimal ringing from each lav engage the FB with each filter in single shot mode and slowly raise the gain until you get a ring and a filter locks in on the ring. As soon as the filter locks in, switch it to parametric mode. Once the gain is nice and strong have the lav helpers move around the speaking areas and see if the FB can lock on any more rings. Once most of the rings are filtered, leave only two channels set on auto mode and they can alternate to catch any transients. One thing to note for anyone using one of these, it is important to have as close to 0db going through this unit as you can get without overdriving it. It detects rings much better when you have a lot of gain going through it. Thanks again Dick for giving me a better understanding of how to operate this unit. -Wes |
Wes....
I actually prefer to do my system corrections with all the channel EQ's flat (or disengaged), then do any remaining adjustments with the channel strips. That way you'll be getting a truer "read" of any room/system anomalies and reserving your individual channel EQ's for a less daunting task and simple tonal adjustments.
DR
Post by: Don Sullivan on October 10, 2009, 10:07:17 AM
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Post by: Dick Rees on October 10, 2009, 10:09:58 AM
| Don Sullivan wrote on Sat, 10 October 2009 10:07 |
The LS9 is a powerful mixer with plenty of tools to reduce feedback.If the 4 bands of parametric EQ on the input are not enough, you can use the 4 bands on the output as well, even if only during the message. In addition, try adding from 5 to 20 ms delay on the output. This can make a remarkable difference. Also, get the lav as close to the mouth as possible, even if it is just under the chin. If these steps aren't enough, consider moving the pastor back or the speakers forward or into a pair rather than a center cluster. ( personally, I despise center clusters ) |
Me three.
Post by: Tim Padrick on October 12, 2009, 03:50:29 AM
Post by: Steve Adams on October 26, 2009, 03:27:35 PM
Our "fix" was an Ashley 31 band eq on the channel as an insert.
This took care of the feedback but the overall sound was less than 100% good quality.
Just this week we auditioned an AT over the ear mic very similar to the E6 (not sure of the AT model number right off) and we disconnected the insert eq and was able to use the 4 band channel eq on the board and this thing sounds GREAT!
I agree with a former poster and would suggest that the pastor take some of the load and wear the over the ear mic.
One suggestion (although some may call it mean, it would get your point across)
Set the eq for the lav so that every time the pastor opens his mouth he gets feedback. It won't take too long before he throws the thing across the sanctuary! Then you can say, "you won't get feedback with this E6..." I'm pretty sure he would be open to the idea of over the ear mics in that situation...
Post by: Ron Balsom on October 27, 2009, 08:49:14 AM