Hello friends,
I would like to hear your opinion,
My PA system includes the Yamaha MGP24X analog mixer and the JBL PRX815 powered speakers.
Until recently I worked with JBL EON speakers and when I switched to PRX I started to get feedbacks when I work with an acoustic guitar with a dynamic microphone and it requires me to keep the gain level low.
I was suggested to add a digital processor to the system - DriveRack PA2, and that way to handle feedbacks and also to get a good equalizer.
Since I work with powered loudspeakers, the processor will not be fully utilized (Limits, Crossover) and will mainly serve as a feedback suppressor.
I also wonder whether it is right to use it as an equalizer or better to use the built-in PRX processor (it has wifi access).
The interface of the DRPA2 through their software looks very comfortable and friendly (really tempting) but maybe I should take "only" a feedback suppressor unit like: BEHRINGER FBQ1000 or DCX2496 or a similar unit of dbx?
On the other hand, maybe there is not a big difference in the cost so it better to have a processor?
I would like to hear your opinion,
My PA system includes the Yamaha MGP24X analog mixer and the JBL PRX815 powered speakers.
Until recently I worked with JBL EON speakers and when I switched to PRX I started to get feedbacks when I work with an acoustic guitar with a dynamic microphone and it requires me to keep the gain level low.
I was suggested to add a digital processor to the system - DriveRack PA2, and that way to handle feedbacks and also to get a good equalizer.
Since I work with powered loudspeakers, the processor will not be fully utilized (Limits, Crossover) and will mainly serve as a feedback suppressor.
I also wonder whether it is right to use it as an equalizer or better to use the built-in PRX processor (it has wifi access).
The interface of the DRPA2 through their software looks very comfortable and friendly (really tempting) but maybe I should take "only" a feedback suppressor unit like: BEHRINGER FBQ1000 or DCX2496 or a similar unit of dbx?
On the other hand, maybe there is not a big difference in the cost so it better to have a processor?
Your problem is a combination of the acoustic guitar, the microphone and their relative position to the speakers. A feedback destroyer may help but it's not going to be a magic bullet. The PRX8xx speakers are certainly better than the EON series but perhaps that extended frequency response is now exciting resonances that the eons couldn't hit.
What mic are you using?
Where are the speakers positioned relative to the performers?
What general frequencies(low, high) do you have feedback problems with?
What mic are you using?
Where are the speakers positioned relative to the performers?
What general frequencies(low, high) do you have feedback problems with?
Acoustic guitar with mics is particularly feedback prone due to all the resonances involved. It's one of the worst combinations. If you use a feedback destroyer like the FBQ2496, realize how they work and what they do. You force the system into deliberate feedback, the FBQ senses feedback and applies a notch filter on that frequency, then to force feedback again until you reach the practical limit. That's all great, but if you move anything physically, even an inch or so, you'll change the resonant frequencies involved and those notches, many of them, won't work anymore. It's a real pain with an acoustic guitar!
I realize what I'm saying here...but could you use a pickup? Far, far less feedback that way.
I realize what I'm saying here...but could you use a pickup? Far, far less feedback that way.
The issue is that I often work with different players that play classical / acoustic guitars without a built-in pickup and it requires me to work with a microphone (SM58).
Does anyone know a quality pickup that can be transferred between guitars?
Does anyone know a quality pickup that can be transferred between guitars?
I remember to read an article some time ago...
I Believe You need something like a frequency shifter... Say 100Hz enters the mike, Speakers produce 110Hz, frequencies don't overlap, and so no feedback. 10Hz pitch change isn't noticed by the audience.
Try the Industry standard Shure SM57 mike first for the Guitar. For voice use SM58.
I believe there are two A versions of each with more sensitivity.
Try them so can use lower mixer gains and place them a little more apart from the guitar.
My brother is Wedding DJ and uses the SM58 A version in front of the speakers.
I Believe You need something like a frequency shifter... Say 100Hz enters the mike, Speakers produce 110Hz, frequencies don't overlap, and so no feedback. 10Hz pitch change isn't noticed by the audience.
Try the Industry standard Shure SM57 mike first for the Guitar. For voice use SM58.
I believe there are two A versions of each with more sensitivity.
Try them so can use lower mixer gains and place them a little more apart from the guitar.
My brother is Wedding DJ and uses the SM58 A version in front of the speakers.
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i've had excellent results with the Fishman Neo D 02 pickup.
i concur that a Shure SM 57 would be a better mic for acoutic guitar.
and if possible keep monitor levels as low as possible to avoid feedback or try relocating the monitor position behind the performer.
if the player is a true classical performer with a nylon string guitar the pickup i suggested won't work you would need a contact mic like the Ischell Airbag C.
i concur that a Shure SM 57 would be a better mic for acoutic guitar.
and if possible keep monitor levels as low as possible to avoid feedback or try relocating the monitor position behind the performer.
if the player is a true classical performer with a nylon string guitar the pickup i suggested won't work you would need a contact mic like the Ischell Airbag C.
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if they are too cheap to add a built in mic for their guitars fine better musicians
(seriously it makes life much more enjoyable)
That said, what is feeding back?
is it the monitors, then move them
if it is the mains, turn them down, re aim them
As for feedback suppressors they squish the music into dull lifelessness
(seriously it makes life much more enjoyable)
That said, what is feeding back?
is it the monitors, then move them
if it is the mains, turn them down, re aim them
As for feedback suppressors they squish the music into dull lifelessness
Re. your guitar.
Have you ever tried one of these (soundhole plug):
Planet Waves Screeching Halt Acoustic Soundhole Cover: Amazon.co.uk: Musical Instruments
They work great for bass/mid feedback which is usually the problem.
Have you ever tried one of these (soundhole plug):
Planet Waves Screeching Halt Acoustic Soundhole Cover: Amazon.co.uk: Musical Instruments
They work great for bass/mid feedback which is usually the problem.
An SM57 and an SM58 share the same capsule. The difference is the grille - the 57 gets the capsule a little closer to the action, so it's a tiny bit more sensitive, and has a little more at the top end since there's not much foam in the way.
That said, I'd expect either to be perfectly serviceable with an acoustic guitar.
What's your speaker positioning?
Chris
That said, I'd expect either to be perfectly serviceable with an acoustic guitar.
What's your speaker positioning?
Chris
Apologies for my half an answer, I got interrupted.
Soo...
...accompanied with one of these:
AKG C 411 PP – Thomann UK
The soundhole plug will not fit every guitar nmbut at that price you can keep a selection to hand.
The pickup is a sound board "stick on" bug based on microphone technology rather than the old piezo bug. Usually placed behind the bridge it works great on finger picked and gently strummed styles. It struggles a bit with heavier styles but would still be an improvement (in my experience) on a dynamic on a stand.
Regarding mikes. The SM58 has a round grille, so it is more omnidirectional than the SM57 which has a grille only on front, probably for better instrument aiming.
Regarding frequency shifting ... it actually was 5Hz
Acoustic Feedback in PA Systems
Regarding frequency shifting ... it actually was 5Hz
Acoustic Feedback in PA Systems
The grille doesn't make that much difference to the pickup pattern, except at high frequencies where diffraction is a concern.
Both mics have the same capsule, which is the part that determines the polar pattern for most of the frequency range.
Chris
Guitarists are never in tune, anyway! (Ba-DUM - pum.....)
Re the main issue: I'd approach it a completely different way. there's no getting completely around acoustic gtr feedback, and even the best pickup / mic combos still give problems & less than stellar sound.
What I've been doing lately is to use "any old" piezo, and then run the gtr through a guitar body impulse response. ( an IR )
This gives nearly zero feedback, and yet the sound, with the right combination, is incredible. Plus, you can change sounds on the fly.
In my case, I use all software to do this, because I'm already running a PC / DAW as my mixer, but there are several great pedals now that do the same thing. Some of them are small and inexpensive, others are expensive, complex, and practically mix your entire show for you, but they all use actual IR's.
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My system: 3 Sigma Audio impulse loader & all of their IR's. IMO, after much searching and trial, these are the best, hands-down. You can even make your steel string sound very close to a nylon string with these. (almost.)
The best little pedal I've personally tried:
YouTube
I loaded those 3SA impulses into it, and it sounds even better than in this demo. And yes, blazingly loud, holding its own wth a rock band.
I'm keeping this around for emergencies, and for when I'm jamming with someone else & don't have my PA / computer.
It also does a credible job of turning my acoustic into an electric guitar, though of course the playability is very different.
Much more expensive units are of course available from many companies. I'm fond of the TC Electronic stuff, personally.
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What's really interesting, once you commit to this idea, is deciding on what guitar to use. Since I own a studio, I've tried this on many of my clients' guitars, and the results do vary a bit. I don't yet really understand what to look for, but clearly the best sounding guitars acoustically don't always sound the best after processing.
Brave new world....
I'm planning on switching to a smallish RainSong gtr when I can, or some other carbon-graphite acoustic. I figure that tuning stability and robustness trumps everything else, once IR's are being used.
Other things you'd probably want to consider: Lack of string buzz, minimal true body resonance, and DEFINITELY a wide dynamic range for the higher frequencies. The Rainsong seems to be exactly right.
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