Jump to content

PA feedback and accordion vs. traditional reeds


Recommended Posts

I'm wondering if there is something about the tone produced by accordion reeds that makes them less susceptible to feedback than traditional reeds.

 

Situation: playing at a ceilidh the other night, in a big, acoustically challenging hall with a fairly rudimentary sound system.

 

I was using my usual setup - Microvox clip ons to a Radial Tonebone DI with EQ to the system, with big wedge monitor and several hotspots.  It's a very loud band - brass, drums, electric guitar - and my problem is always getting enough volume from the concertina in the monitors , so I can hear myself, without producing feedback. In this instance,  I assume  the dynamics of the hall made the problem more acute. 

 

As an experiment, I switched from the Jeffries anglo - traditional reeds - to a similarly pitched Morse, with accordion reeds.  The problem didn't disappear, but I was able to crank up  monitor volume on the concertina a few notches without feedback.  I was much more able to hear myself.

 

Is there some characteristic of the sound of accordion reeds that might make them less susceptible to feedback than traditional reeds? Is it the more complex, overtoney sound?

 

I'm beginning to think that hybrid concertinas play better with diverse sound systems than traditional reeds.  I'm fed up with the variability of the Microvoxes - they work OK in some situations/venues, very poorly in others, and not at all in at least one - for some reason, on some PA systems, the Microvox just doesn't produce enough output.  I am switching to a  high quality condenser mic that the sound pros at a gig last year used on the concertina with much better results.  But I'm also wondering if there are sonic advantages when amplifying the hybrid that outweigh my personal preference for traditional reeds.

 

 

 

 

 

Edited by Jim Besser
Link to comment
Share on other sites

24 minutes ago, Alan Day said:

I always found that I had to turn up the base and take out the treble in large halls to create a better sound.Not really answering you question but worth a try.

Al

 

Yep, I do that, too.  The Tonebone EQ helps.

 

I'm hoping my new setup will be an improvement - a single, high quality condenser mic that several sound techs have used when working with me. 
What's so frustrating about the Microvox setup is the variability; the same configuration works fine in some halls, terribly in others.  I really want to simplify things while working to reduce the feedback problem.  Another factor is that I hate getting tangled up with all the cables when using an attached system.

Link to comment
Share on other sites

I tried many systems and I came back to two stands with Shore Mikes set about 18 inches from the concertina to allow for bellows movement ,either sitting down or standing up.You cannot move around the stage, but that was the best for me.

Al

Link to comment
Share on other sites

1 hour ago, Alan Day said:

I tried many systems and I came back to two stands with Shore Mikes set about 18 inches from the concertina to allow for bellows movement ,either sitting down or standing up.You cannot move around the stage, but that was the best for me.

Al

 

With a probably much lesser amount of experience, that's what I'm doing as well (two stands, two condenser mikes).

 

Best wishes - ?

Link to comment
Share on other sites

5 hours ago, Alan Day said:

I tried many systems and I came back to two stands with Shore Mikes set about 18 inches from the concertina to allow for bellows movement ,either sitting down or standing up.You cannot move around the stage, but that was the best for me.

Al

 

I've used the 2 mics/stands setup many times, and it works, but sound guys tell me there's too much variation in volume as the bellows move in and out.  A top sound guy I've worked with - he does both studio and live sound - insists that a single really good mic on a stand over the middle of the bellows is the best solution, although not perfect.  My new setup is a single Shure KSM137; the sound tech at a very large venue last year used one when my Microvox failed, and the results were excellent.

 

But my question remains: are accordion reeds inherently less susceptible to feedback than traditional reeds?  My recent experience says yes, but I'd be interested in knowing if there's any science to back this up.

Link to comment
Share on other sites

Interesting discussion I found that using two mikes, but with a large gap between the mikes and the bellows evened out the sound of the bellows at full stretch and closed.

I did many experiments with condenser mikes .Inside the box ,taped to my hand ,screwed onto the face plate under my hand and the condenser mike on adjustable foot long spring arms ,similar to reading lamps. It did not work.

Accordion reeds are usually in blocks on a plate and not equally spaced around the box as a standard construction concertina, it may be that there is more of an equal spread of sound with accordion reed construction. Only a guess Jim not a fact.

Al

 

Link to comment
Share on other sites

4 hours ago, Alan Day said:

Interesting discussion I found that using two mikes, but with a large gap between the mikes and the bellows evened out the sound of the bellows at full stretch and closed.

I did many experiments with condenser mikes .Inside the box ,taped to my hand ,screwed onto the face plate under my hand and the condenser mike on adjustable foot long spring arms ,similar to reading lamps. It did not work.

Accordion reeds are usually in blocks on a plate and not equally spaced around the box as a standard construction concertina, it may be that there is more of an equal spread of sound with accordion reed construction. Only a guess Jim not a fact.

Al

 

 

Good theory, Alan! 

 

I'm also wondering about the character of the sound: the pure tone of concertina reeds vs. the overtone-laden tone of accordion reeds.  As I noted, the difference in feedback was striking.

 

Your experience with condenser mics is interesting.

 

For me, I have two data points.  In the big dance hall where we frequently play, the very good sound guy generally sets me up with a single AKG535 condenser mic on a stand, and the sound is pretty good, without a lot of trouble with feedback.  He is able to do this with skillful EQ even though he is mostly using old and not top-rank equipment.

 

 In two gigs at Washington's Kennedy Center Millennium Stage, where the Microvox clip ons couldn't produce enough output for their system,  a single Shure KSM137  produced the best sound I've had: a clear, strong sound without the harshness of the Microvoxs and without feedback..

 

Of course, a lot of the latter good experience is because they were using top professional gear throughout the system, on an acoustically excellent stage,  and because they are sound professionals who have the experience and expertise to deal with hard-to-mic instruments.

 

Which leads to another conclusion: here on c.net, we have discussed the best systems for amplifying a concertina for many years, with no  strong consensus about the best approach, and part of the reason is that we are just not sound professionals, and we're generally using less than optimal PA systems.

 

So we're always seeking the magic microphone that can offset our deficiencies.  A skillful professional can get good sound out of a variety of mic systems.

 

I'm going to give the Shure a try at an upcoming dance in a very noisy, acoustically hot hall; that should be a good test.

Edited by Jim Besser
Link to comment
Share on other sites

It seems to me that "feedback" can be an issue in two ways. One is "howl round", when the loop gain is enough to cause continuous sound. Different original sounds may provoke that more or less quickly, but it will happen anyway. The other is where the loop gain is a bit below unity but enough to emphasise one or more frequencies. That clearly is more or less of an issue according to how much of those particular frequencies an instrument produces, which may indeed differ significantly from one kind of reed (and associated chanber etc) to another.

Link to comment
Share on other sites

6 hours ago, Richard Mellish said:

It seems to me that "feedback" can be an issue in two ways. One is "howl round", when the loop gain is enough to cause continuous sound. Different original sounds may provoke that more or less quickly, but it will happen anyway. The other is where the loop gain is a bit below unity but enough to emphasise one or more frequencies. That clearly is more or less of an issue according to how much of those particular frequencies an instrument produces, which may indeed differ significantly from one kind of reed (and associated chanber etc) to another.

 

Interesting, and it makes sense.

 

That leads me to another question: I frequently hear that systems like the Microvox are particularly susceptible to feedback.  Why would stick-on mic be more problematic than mics on stands?

 

Link to comment
Share on other sites

I mentioned stick on condenser mikes and the first problem with them is that you get massive sound volumes from reeds close to the mike huge gasps of air if it is near to the air valve.

The other thing is when playing an Anglo or Jeffries duet standing up, some of the valves are being baffled by the hand .(not confused). The English and other duets are held differently .

Another theory. to a thought provoking subject.

Al

Link to comment
Share on other sites

It could be that the Microvox has an omni-directional pick-up pattern so take sound from the monitors and the room, as well as the instrument, which tends towards a feedback loop. Mics like the KSM 137 have a cardiod pick-uk pattern which helps to reject any sound source except the instrument.They are also better quality than the Microvox which will also help with feedback rejection. In general quality (not cheap) mics will give better fidelity and easier set-up. An example of a bad mic is the tie-clip mic frequently used as a low cost guitar mic; they are a nightmare. If the gain is raised enough to get sufficient volume the feedback is horrendous. I have been doing sound for acoustic gigs for 30 years and my experience is that quality mics will give much better sound and be easier to work with. Having said that I have not yet experimented with amplifying the concertina but am currently looking at using two end-addressed small condenser mics on a T bar, one addressing each end of the concertina. By using good, sensitive units the gain does not have to be too high (which helps combat feedback) and the mics do not have to be so close that action and bellows noise become a problem. Before I get the small condensers I might try the Rode M2 stage condenser vocal mics that I have as their tight pick-up pattern and good sensitivity may well be a good indication of the suitability of pencil mics such as the Rode NT5s.

 

Because the sound source moves as the bellows open and close any mic that needs close micing will suffer from volume variations. A good condenser mic, by virtue of its greater sensitivity, will allow the mic to be further away so reducing the perceived volume changes and even out the sound.

 

An answer to the insufficient monitor volume, which leads to feedback when raised, is to use hard-wired in-ear monitoring. They are not as convenient as wireless units but are much cheaper and by eliminating the open monitor speaker they remove one of the feedback sources.

 

Dick.

  • Thanks 1
Link to comment
Share on other sites

3 hours ago, DickT said:

It could be that the Microvox has an omni-directional pick-up pattern so take sound from the monitors and the room, as well as the instrument, which tends towards a feedback loop. Mics like the KSM 137 have a cardiod pick-uk pattern which helps to reject any sound source except the instrument.They are also better quality than the Microvox which will also help with feedback rejection. In general quality (not cheap) mics will give better fidelity and easier set-up. An example of a bad mic is the tie-clip mic frequently used as a low

 

Thanks, that's all useful information.  And you're absolutely right about quality mics.

 

Over they years I've tried all kinds of arrangements - the Microvox, 1 or 2 SM57s, etc. - but the best sound I ever had was with a single KSM 137 in the hands of a real pro.  My hope with my new 137 is that I can improve sound, reduce feedback - and make setup as simple as possible.  I want to play music, not fiddle endlessly with equipment and get tangled up in cables and beltpacks!

 

And at my next gig, I'm going to use the hybrids.  What I've realized is that while the sound of a Jeffries is bliss to me, dancers in a crowded, noisy hall, hearing the music thru a big PA, can't tell the difference.

 

 

Edited by Jim Besser
Link to comment
Share on other sites

I am on holiday at present but will do some experimenting when I get home and will report on the results. Set ups to be tested will be two spaced condenser mics, a singe mic located centrally above the bellows and also a single placed centrally in front of the bellows. This latter placing should help with the feedback problem as the monitors will be in a null point to the mic. When placed overhead and pointing down the monitors are on the edge on the pickup range of the mic with the attendant danger of feedback loops. The mics will be the previously mentioned Rode M2s.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...