Live and Loud - Feedback Please

[debra]

...
I took the replacement mics in with the originals to have them swapped out to a reputable person.  The nature of the work was a little more complex than simple soldering as these components need to be bent into place through some plastic connector bits.

I got them back today and only 2 out of 6 of them work  .  None of the bass mics and only the two middle treble mics.

I don't know if the mics are at fault or if this is a poor soldering job.
...

There are much better systems like AZS and Harmonik, but they are really expensive.
The Microvox system I have been using successfully is a nice compromise between having good mics, not too much trouble with feedback and nothing to be installed inside the accordion.
But when things matter less, the cheap microphone system I got from carinidena.it actually works very well too. It does require installation inside, but it performs very well. In our orchestra we use it on the two bass accordions and we get great sound.
There are several systems that do work well, but finding them can be a bit of trial and error. Sorry to hear you ended up on the "error side" of that equation.

 

[jozz]

There is no indication anywhere of what these components are, not even on the pictures on ebay.

I took mine apart today and the bigger one is marked CZ034

fairly common by the looks of Google

 

[Glug]

Theres a data sheet for the CZ034 here: http://ozeas.sdb.cz/panska/1A/E_laboratore/Zadani_uloh/zad21/mikrofon.pdf

 

[jozz]

When you browse around you will find a lot of these with similar dimensions peaking at about 110db SPL.

For instance: this

There are more expensive ones with 3 pins, that go higher than 140db but I doubt those are used in this mic kit..

That said: I doubt you can play your accordion at 110db. What is that, a jet taking off? Theoretically this SPL might not be the cause of all this...

 

[Mr Mark]

I still do not know the cause of the distorting mics.  I do know the smaller mics had fixed the problem temporarily.

I got them back yesterday and the reason only 2 out of 6 worked after the first repair/replacement was because the person doing the soldering did not check polarity first (and there is no indication on the mics themselves).

When I got home before installing I did a quick test and found that already one of the freshly soldered joints had failed.  So I fought with it and got it resoldered and it is still working hooray.

Unfortunately the bass mics have both fallen off where they were attached.  They were working briefly but one solder joint failed on its own (just from moving around and playing).  When that occurred I had the idea to relocate the remaining mic to the centre of the reeds (because being located at one end produced substantial (easily noticeable) differences in volume depending upon how close the reeds are to the mic) but unfortunately in doing so the other mic has become detached as well.  The solder connections are so damn finnicky it is damn near impossible to have this happen...

So I just hope the remaining treble ones do not fail.  Maybe I can get the bass ones resoldered but I am not sure there is any point because I cannot get a useable level of volume (too quiet or too loud depending upon how far the reeds are from the mic).

At the end of the day this treble configuration works, clear sound, no distortion and so far minimal feedback...and no annoying hiss.  I have band rehearsal later today so we shall experience a real live test for once, but I am hopeful.  I just hope the rest of the solder joints do not fail.

I think I am beyond 3 months of getting my money back at this point.  I am disappointed on the lack of explanation why the first mics were problematic.  I had to shell out even more cash to get the replacements fixed and even that only worked part way...part of which may be the fault of the repair person but how am I to know and what recourse do I have.  At the very least this person reckognized the error in polarity and did not charge me for the second round of repairs.



I do know that after four different microphone setups I still do not have something that is fully functional...and no longer have the resources to pursue this - being; time, money and energy.  I also do not have the trust - three manufacturers have let me down and two accordion repair shops locally have let me down.  There are definitely lessons to be learned here for anyone reading.  Namely, buy $omething that works out of the box, and don't underestimate the sheer complexity of accordion microphones - it can be an absolute nightmare.


Thanks everyone for trying to help.

 

[JerryPH]

Mark... I am sorry to read all this. Really, it is NOT supposed to be as difficult as what you went through. I feel that maybe you were the victim of a comedy of errors.

The basics of making an electret mic function is technical childs play, however it seems that you started off with a defective unit and went downhill from there by introducing incredibly incompetent repairers and disreputable sellers. Why would a solder joint break and cause the mic to fall off in the first place is clear evidence of this... on top of all the other things that you went through!

I started to do some research and pricing to make my own kit years ago (http://syner-g.no-ip.biz/mymusic/custom-high-end-mic-system/), but in the end, since I dont use that accordion for live gigs, decided to go the route of external high end condenser mics, which give best quality sound possible for my needs and I still may one day yet undertake such a project as it is not all that expensive to purcahse the parts and I would actually find it fund to see what I could do with the sum of well under $150... I bet many would be surprised.

 

[Mr Mark]

Resurrecting this oldie but a goodie  .  Good to have some decompression since my last post.

I finally found a place to do competent solder repairs, so all mics are working!

First hurdle down (sort of) and it only took about 6 months  .  The mics do not distort and are very clear, but feedback is very easy to achieve - for the most part floor monitors are a no go - so IEM it is but there are issues there too (more below)...



I do still have to sort out a better location within the accordion for the bass mics OR somehow utilize compression to even out the volume discrepancies.  Probably a combination of the two.  Which means box modification but I am actually not sure that can be done.  Damn it is a tight fit in there!


I also have to sort out how to send the signal wirelessly in stereo.  If there is a system out there which anyone knows of I am all ears, otherwise increasingly this is looking like modifying the output so that it ends up as two output jacks and running two separate mono wireless signals (1/4).  I do have the ability currently to sum this stereo into a mono, but the result means I have no external control over separate channels, which I would really like and in the interim kind of need due to the aforementioned bass volume level issues.  In retrospect it actually makes sense to have a similar mic setup as on the treble side - with multiple mics running the length of the soundboard...but it is what it is...
 

Further, I have run into the issue of live in ear monitors not being loud enough...also the fact that these mics pic up the VERY loud drums beside me more so than the accordion itself...almost?  Its been really hard to pin this one down.  It does seem I at least need to boost the gain somehow into my IEM, which I can probably do in the interim with the DI I have.  Not the largest of concerns but worth noting...

It does seem liker I am needing another piece of gear.  A stereo DI or splitter at the least.  So I can either cable or wireless run into the box with to separate channels (bass treble) for independent control and then out into the sound system (for the engineer to control).  Running this summed as mono is definitely going to compromise the overall quality and level of sound.  Thinking of something like this https://www.long-mcquade.com/11046/...es/ART_Pro_Audio/4-Channel_Splitter_Mixer.htm or this https://www.long-mcquade.com/840/Pr...xes/ART-Pro-Audio/Dual-Passive-Direct-Box.htm .  It would be good to have more than single outputs for each channel so I can run these into my IEM and the main mix.

So much to think about and consider.  

What are your thoughts on a compressor for the bass section first off, and second of all what about a feedback killer of sorts?  I am skeptical on the latter because unlike with guitar feedback (which I can control a lot easier) this feedback is not all that controllable...these mics are super sensitive and either there is no feedback or a slight turn of my body the wrong way and everyone is deaf.  On or Off.

This is truly the wild unknown, feeling kind of like a wright brother except I have no clue on the concept of flying.

 

[AccordionUprising]

I do think this is important. I'd love to see a concise "best practices" for different cost levels and environments for amplifying accordions.

Historically, I think this was (and remains) one of the reasons popular music abandoned the accordion.

As a counter-example, off-hand I'm not sure how the norteño accordionists here in North America mic theirs. They almost all only play treble on their button-boxes which simplifies things a lot. But they sure play in big loud bands.

Keep up the good reports.

 

[jozz]

Sounds like you are boosting the signal at a location that you shouldn't boost.

Can you describe the complete chain you are running, so from the mic's to the desk to the IEM and to the PA, and what devices there are in between.

If you thought about running compression on the INPUT/send part of your chain, stop right there. This will induce feedback beyond your wildest dreams.

Keep it simple, only send a dry signal to the desk. Set your input gain properly and take it from there.

 

[debra]

Resurrecting this oldie but a goodie  .  Good to have some decompression since my last post.

I finally found a place to do competent solder repairs, so all mics are working!

First hurdle down (sort of) and it only took about 6 months  .  The mics do not distort and are very clear, but feedback is very easy to achieve - for the most part floor monitors are a no go - so IEM it is but there are issues there too (more below)...

...

Good to hear that everything is working now.
Regarding the feedback: the placement of the speakers is important, as is dampening resonance through the floor. Floor monitors should not be a problem if properly "cushioned" from the floor. I know the problem well from wooden stages. A carpet under the speaker is the least you should have, a pillow or piece of foam probably better. You can also try to find out which note resonates the most through the floor and use an equalizer to dampen that note. (When I have time to set up I always look for that and eliminate the problem with the Bose Tonematch engine.) As you probably know I use the Bose L1 model 2, mostly to amplify the bass accordion, and in the larger orchestra I use two stacked bass units, and the speakers are always at least partly behind me so they function as room speaker and as monitor at the same time. No feedback issues (using a cheap mic system from Carini in Castelfidardo) unless the speaker is way too close to me. I can always go louder than needed, but sometimes the equalizer is really needed to eliminate resonance from the floor. When you have feedback issues with a bass note it's not the mics or the speakers that are the problem, it is the floor.

 

[Mr Mark]

Sounds like you are boosting the signal at a location that you shouldnt boost.

Can you describe the complete chain you are running, so from the mics to the desk to the IEM and to the PA, and what devices there are in between.

If you thought about running compression on the INPUT/send part of your chain, stop right there. This will induce feedback beyond your wildest dreams.

Keep it simple, only send a dry signal to the desk. Set your input gain properly and take it from there.

jozz- Ok, a lot of variables.  I have tried to use every combination of boost I can think of.  As I experiment further I am having further realizations.


One problem I am having is that it is just me, and so far in the confines of my room adjustments are made being within arms length of my monitor (this is a battery powered Traynor TVM50 - which has two inputs 1 being XLR or 1/4 which has a volume adjustment and a single tone knob, and the other input being a 1/4 input with Gain, Volume, Bass, Mid, Treb and Hi/Low input pushbutton selector).  There is also RCA inputs but I dont use those.  It is really hard to operate like that without feedback.

For simplicity sake I will run a Stereo 1/4 cable from the accordion into a splitter Left and Right Mono 1/4 jacks which  then feed into the two inputs of the amp.  I use the 2nd input for the treble of the accordion as it has the most eq adjustments as well as gain - so more control over the sound that matters.

What has worked best is to crank the volume on this channel while leaving the gain at about 2/10.  Bass 1...Mid 2...Treble 7.  On the accordion the knob is at about 75%.  Anymore gain on the amp it tends to distort.  I actually need another amp, this one isnt loud enough, but it is what it is.

For the bass side the accordion knob is cranked.  The volume on the amp is at 5 and the tone 1 (these numbers are all out of 10).  The tone isnt as good because of significant db loss between notes (almost 10db between the most quiet and loud noted due to mic location).  Any louder on the amp and the feedback happens.  I need to relocate these mics centrally instead of at the bottom end of the soundboard - the difference is quite noticeable.

I played a gig last night (looks like the last one for awhile) and just used the amp - no PA.  Projected out into the crowd.  Had to really up the pressure on the bellows to cut through...I was bending notes.  But I didnt actually feedback unless I got too close to the amp.  Hooray!  BUT - had a heck of a time with the In ear monitors due to the Bass guitar and Drums being picked up by the accordion mics and going in my ears.  Unfortunately there is no way anyone in the audience was going to know any better what was what coming from my amp with mains right beside it (small venue) so I couldnt ask anyone for sound feedback...although I was told I could be heard, but not probably loud enough.

There is one other item in my signal chain, only on the treble side.  Between the accordion and amp I have installed an ABY (its all I have) which splits things into two channels - one going to the amp and the other going into my DI box so I can crank the gain and send it into my IEM (so they can be heard).  I do try to keep my signal chain simple going to the amp, and in this case it really is - I got rid of the Para DI from the chain (except to use as a boost for my IEM) because it wasnt helping any.  Also in this instance I went wireless so had no bass in the amp, only treble.


So back to my room, generally I am making adjustments at arms length and it is feeding back.  The same happens in rehearsal space.  I need another set of hands.  After playing last night I have realized I cannot have the amp anywhere but well in front of me projecting away from me.  It cannot be beside me or behind me, even with minimal gain on the accordion knobs or it goes bezerk...which means I cant use it as a monitor.  Also in every instance where there has been floor monitors I cant have any accordion in there or my band hates me.

[font=Tahoma,Verdana,Arial,Sans-Serif]Thanks for the input on compression...I am definitely a believer of less is more in the chain.[/font]


Also stopped by the music store today before everything shuts down...looked at a lot of DI boxes and such...it seems the best thing to get IS going to be a small mixer after all.  At least based upon price point for now.



I also couldnt help but to put a down payment on a Roland FR3-S on sale.  With any luck Armageddon wont happen and I will own it by years end or sooner.  Very excited about that.


debra - We are always using whatever monitors the venue has....which was none last night so we had no feedback issues.  But when we do the accordion is always causing grief.  I will have to remember to bring carpet or something next time but again this kind of feedback is all or nothing - it happens without even playing a note so there is no note to isolate (which is why I had bought the Para DI as it does have some capability that way and I was able to utilize it somewhat with the sm58 I had installed).



Sorry, long post.

 

[debra]

...
debra - We are always using whatever monitors the venue has....which was none last night so we had no feedback issues.  But when we do the accordion is always causing grief.  I will have to remember to bring carpet or something next time but again this kind of feedback is all or nothing - it happens without even playing a note so there is no note to isolate (which is why I had bought the Para DI as it does have some capability that way and I was able to utilize it somewhat with the sm58 I had installed).
...

I should have said  that of course: when you get feedback without even playing a note, and when that feedback is a low drone, it is the frequency of that feedback that is what is going around through the floor. That is the frequency you should then dampen using an equalizer.
That feedback will go away when you insulate the monitor from the floor using foam or at least a carpet. But as you change what it is the loop it may also alter the frequency of the feedback, and you need to adjust the equalizer accordingly.

 

[jozz]

Well good thing the mic system finally works!

Key thing here is try to do your settings during a lengthy soundcheck at the venue instead of in your room. First set that EQ all at 5 (neutral) and start over.

Couple of considerations:

• iis that ABY pedal active or passive? does it have builtin gain?
• your mic system is hi impedance and that Traynor seems to have two different inputs, one mic and one instrument, so normally you would set the button at Hi-impedance for that input. If you set it low, you will get more of these spikes.
• a 50 watt solid state amp will be ...modest... standing beside a pounding drummer, for comparison on gigs with backline, I need to run a 200 watt solid state next to a 100 watt tube guitarist. If you decide to bring that amp, the rest of the band should turn down, or you have to go direct in and only use your amp as personal monitor.
• If you come across any knobs/faders that are so delicate and have a certain treshold value and after that everything spikes / goes berserk, then you can conclude your gain staging is wrong. This also goes for orienting your accordion on stage, if it immediately spikes from that, you are running way to hot somewhere in the chain. Main suspect is your EQ, which could be like low -9db, mid +3db and highs +7db. Think more in adjustments of 2db max.
• Start with everything neutral (EQ all neutral (5), gain 0, volume 70) and accordion pots at 40. Monitor with the headphones straight at the amp. If you can get good S/N, go on to the next stage.
• Rule of thumb: if you have to touch EQ, look at turning down mid EQ first. Refrain from turning eq UP (past 5), instead only turn EQ down. This way, your feedback will be less. If you need to go up, you go up by volume first and not with EQ. Or turn up all eq at once, if you're lacking volume in the end.

If you think you need to buy something, get an amp with direct out.

 

[Mr Mark]

debra - yea, it seems more a gain staging issue than anything...when I have equed the offending frequency down another one immediately pops up.  At the end of the day I have found myself absolutely zeroing all of the frequencies on more than one occasion, which makes me believe it is something else.

jozz-

The ABY is by Radial, is passive and does not have gain control.  The only reason I am using it is to split the channel so I have something to feed my IEM.  When testing that vs cutting it out of the chain entirely there is no noticeable difference through the amp or with feedback, although I am aware there may be differences I am not hearing.

Yes, I do have the High impedance selected on the amp.

Great to know on the wattage.  My band turning down is not an option unfortunately (I am aware of this issue but the youngins are less receptive ) so I am stuck with having to source more wattage...which isn't really an option right now so DI and or large backline if possible.  As mentioned I cant use this amp for monitoring because of feedback but if I can sort that out then sure.


I hear you on the max eq adjustments and am aware less is best.  I think more and more fundamentally this is not something I have a lot of negotiating power with due to lack of wattage so volume on the amp and accordion are (mostly) cranked and the gain is maxed out without distorting sound.  But I will go about starting with 5 (midway) and turn down from there.


Of note, I have played a half dozen different venues of late and every sound guy has struggled with accordion feed back (except the last show where I just ran through the floor).  In every instance we have cut the accordion out of the floor monitors and it is less problematic, but as soon as I am beside the mains or in front of them...BLAMMO...so usually I am relegated to being token accordion guy beside the drums...which doesn't help but at least for the first time in my life I have sympathy for the drummer!!!

 

[debra]

debra - yea, it seems more a gain staging issue than anything...when I have equed the offending frequency down another one immediately pops up.  At the end of the day I have found myself absolutely zeroing all of the frequencies on more than one occasion, which makes me believe it is something else.
...

Once you equalize out one low frequency you have eliminated the floor resonance. Other frequencies that again cause a feedback loop indicate the feedback just goes through the air and that you have reached the maximum amplification you can have in that venue.
Here is an example of one of my performances. If you look near the top right corner you see one person standing up, to his left a grey pole (streetlight) and to the left of that a black pole which is the Bose L1 model 2 that amplifies my accordion. So the speaker is (far) behind me and is more than loud enough that when the whole orchestra starts playing loudly I can still hear myself quite well.
On the accordion you may perhaps still make out that on the treble side there is a bracket on which the Microvox 420 unit is mounted. (On the bass side there is another mic.) With this type of setup I have never had feedback problems that prevented me from getting enough amplification. So I do not use a monitor in front of me, blasting towards me, but a speaker behind me which projects the most of the sound a bit to left and right so as to not cause me to go deaf while blasting the sound forwards. The bass speaker (not visible here) simply projects forwards, so when feedback is about to happen it always starts with sound coming from the bass speaker. But again, not a problem with my setup. For most performances the speaker is quite a bit closer than in this picture. Obviously the choice of mics and their enclosure matters.

 

[jozz]

In every instance we have cut the accordion out of the floor monitors and it is less problematic, but as soon as I am beside the mains or in front of them...BLAMMO

  okay so you are doing flogging molly besides or in front of your mains...

that might be a challenge yes. You could only kill feedback in that situation, with pinpoint EQ-ing on the desk (technically it can be done)

still, if it spikes that much, you must mostly look to EQ because that's where you are boosting high's

 

[Mr Mark]

Well you know, if you are gonna blaze the lead licks of Salty Dog you damn well better be front and centre of your band ESPECIALLY if your band is operating at Warp 9...  

In all seriousness though there are six of us and some really small venues, so its gonna happen lol - I am always fair to the soundman ahead of the gig to be ready on those faders but they aren't getting paid much and tend to wander.  But that usually only happens once  .

Less is more for sure, I appreciate all the feedback here jozz, the mics are finally working properly is the main thing, now I just have to up my ampage and tweak what eq I have in the meantime.


debra - I am seriously curious as to how well your setup would work in a small venue with a rock outfit pushing 120-130 db's.  We are definitely too loud for our own good but that is beyond my control   .  It would be good to hear some samples of your ensemble at work!

 

[debra]

debra - I am seriously curious as to how well your setup would work in a small venue with a rock outfit pushing 120-130 dbs.  We are definitely too loud for our own good but that is beyond my control   .  It would be good to hear some samples of your ensemble at work!

Here is an illustration of the problem Im referring to:
You can clearly hear the problem of a low bass note going through the floor.
We could have eliminated it is we had more time to diagnose the problem...

Here is a video without problem: in a different venue. You can make out one Bose L1 model 2 pole. We used two of them.
Everyone except the bass player is using a Microvox 420 unit. (The bass came with Sennheiser mics built in.)

We try to offer our audience a concert experience, not a lets see if we can destroy your ears experience.
That makes our life easier.

 

[Dingo40]

To paraphrase: Waldo Emerson once said, if you want to go on a journey, you can either spend months or years working to get enough money to buy an outfit ( horse, cart, etc) for the trip, or simply set off on foot right away.

It rather seems to me that this parallels the issues on this thread: you can either pick up and play your acoustic instrument right away or spend months/years tweaking your electronic equipment instead.

The reason for all this appears to be to produce sufficient volume to be heard, but doing so, constantly introduces unwanted complications . And so it goes on.

When I was a boy, none of this gear had even been dreamed of, yet musicians (even accordionists) appeared to have no trouble making themselves heard. Have we lost our hearing? Have instruments lost their capacity to project?

The chief advantage of acoustic instruments has always been their independence of a power supply: just you and them

 

[John M]

. . . You can also try to find out which note resonates the most through the floor and use an equalizer to dampen that note. (When I have time to set up I always look for that and eliminate the problem with the Bose Tonematch engine.) . . . 

[font=Tahoma, sans-serif]Paul,[/font]

[font=Tahoma, sans-serif]I have a question on setting up the equalization on the Bose Tonematch.  I am trying to reduce resonance at A2 = 110 Hz.  I am Selecting Para EQ band 1.[/font]
[font=Tahoma, sans-serif]1st, I rotate the Level control to -12 dB[/font]
2nd , I rotate the Freq control to a center frequency of 110 Hz
3rd , I press the Freq control to switch to  Width and set the bell curve width to 0.2 octave
 
I can hear the “cut” in output.  My question is:  How can I tell afterward, that I have set a -12 dB cut at the center frequency of 110 hz?  If I rotate the Freq control from 50 Hz to 16 kHz, all the frequencies show a -12 dB cut.  I thought I would see the “bell curve” drop off with a peak at 110 Hz and a drop off to 0 dB at +/- 0.1 octave.
 
John