Are there disadvantages to installing condenser mics to the inside of the accordion?

[JerryPH]

Agreed, this would be true at any possible listening position. But if you were an ant and could place yourself right next to a pallet (where my microphones had been placed), it would sound very loud. Some microphones might distort well below 120 dB. I suspect Limex used inexpensive mic capsules, which were probably not designed for very high SPLs.

Not sure why you would specifically say Limex mics? Their systems are normally touted as being one of the best (albeit expensive so not popular)? 10 treble mics and 3 bass mics is what I have in my system.

Last month had you asked me about Limex mics I would say that I am clueless, but I've just had a chance to play with the Limex mics in my Beltuna, and I have a couple personal observations:

- Without any EQing, they sound REALLY good (meaning natural and super flat frequency response when mic EQs are disabled and they do have a - or + 15db gains in low-mid-high controls integrated if desired. For my recording they were set to "0" and I EQ'ed very lightly in post).

- From Limex, the 3 bass mics are tuned from the factory to be slightly more sensitive than the 10 treble mics from the factory, but then again they are deeper inside the bass side of the box and more separated from outside sounds.

- How sensitive are the Limex mics? Sensitive to peg my meters of my Mackie mixer to 0db at the 34% level in the mic settings on the accordion and the gain on my mackie set to 50%. That is also sensitive enough that I can record the music perfectly and **still** listen to the backing tracks over the speakers of my audio setup 5-6 feet away clearly enough that I can play along.

- No acoustic accordion in the world can make a note loud enough that's close to overloading any electret mic, I don't care if you glue them to the reeds directly... lol

Now, if you want to overload the mics, set all mic volumes to 128 (maximum) then stand facing in front of a 3,000 watt woofer at full volume and wait for the feedback and the coming hearing loss... lol

BTW, speaking of feedback, Limex has an ingenious system for helping reduce/kill feedback in situations where other systems may easily induce unwanted feedback... the MIDI is used as a sensor to act like an ON/OFF switch for any treble or bass mics, so you could be standing in front of a speaker and have ZERO feedback, but still have functional mics the moment you press any note and the MIDI tells the system that the key or button is pressed and then turned off the moment they are released... very interesting!

 

[SteveBox]

I have few* complaints about the Limex microphone system, except in my case, the installer was not able to place them where they were intended to be, because there was almost no clearance between the pallets and the grill. The treble side amplification did not sound good until I experimentally moved the grill away (with the microphones attached) by an inch or two. The only explanation/theory I can think of is that the microphones distorted when they were nestled between the pallets, as the closer one gets to a sound source, the louder it becomes.

I have a Limex MPR3 system, which is two generations older than the current system. Limex could have made improvements since then. I am sure my MPR3 does not have the audio muting feature you describe controlled by the MIDI.

* Well, I do have one other complaint. Digital noise could be heard in the audio when not playing, which I found annoying. The replacement microphone system I designed keeps the audio wiring and circuitry completely separate from the digital electronics. If Limex is now muting the audio when not playing, then maybe that takes care of this problem.

 

[JerryPH]

I have few* complaints about the Limex microphone system, except in my case, the installer was not able to place them where they were intended to be, because there was almost no clearance between the pallets and the grill. The treble side amplification did not sound good until I experimentally moved the grill away (with the microphones attached) by an inch or two. The only explanation/theory I can think of is that the microphones distorted when they were nestled between the pallets, as the closer one gets to a sound source, the louder it becomes.

OK, I am starting to understand. I also am willing to bet that I know what caused this AND how to solve it (proper installation aside, because my mics were so close that on 3 notes I heard a "click" as the arm of the mechanism hit the mic, a simple thing to adjust in about 15 seconds).

Proper gain staging.

If you are hearing distortion, your mic volumes on the accordion side and/or the mixer side are simply too high. There is a HUGE difference between distortion and mic overloading, though they do sound the same to the people that are not aware of the minute sonic differences. Try setting the mixer levels to about 60-65% and setting your accordion mics to 0% and bring them up in increments of about 5% until you can clearly hear them, but don't go over 75 out of 128. Back it down 5%, adjust the mixer so the loudest you can play hits the "0" on the mixer and then play as loud as you want... tell me if it distorts then (I bet it won't... possible electrical issues aside!).

Now of course the proper way is to make sure that you keep the mic settings UNDER 70 (out of 128) and adjust the gain on the mixer, your distortion will magically vanish. This is a good starting point.

I have a Limex MPR3 system, which is two generations older than the current system.

The exact same model that is on my Beltuna.

Limex could have made improvements since then. I am sure my MPR3 does not have the audio muting feature you describe controlled by the MIDI.

* Well, I do have one other complaint. Digital noise could be heard in the audio when not playing, which I found annoying.

Nothing electronic that is old will work 100%. I hear a tiny high pitched whine from my dispay screen, its not concerning and is not injected in to the recordings, but is something I will address one day... maybe.

Buzzes/hums electrical noises introduced in to the outputs are often bad grounds, poor install quality or electrical components that are slowly failing, and are all addressable by someone knowledgeable. Don't look at me, my skillset is very specific (meaning limited... lol).

The replacement microphone system I designed keeps the audio wiring and circuitry completely separate from the digital electronics. If Limex is now muting the audio when not playing, then maybe that takes care of this problem.

Nope that is an option specifically for stage players who play benhind or around loud speakers and kills feedback caused by loud surroundings. If you have an MPR3, you have it too. Download the manuals, do a little fast reading, its convoluted and badly written, but there.

 

[SteveBox]

Jerry,

I understand gain staging, and I don't think that was my problem, at least not with my mixer. When I was using the Limex microphones for several years, it did not sound obviously distorted, but it was not a pleasant, natural accordion sound, adequate, but not that good. It took some time to reach this opinion, and by then my installer had gone out of business. I experimented with EQ, and tried other amps, but could not find any combination that sounded satisfactory. Then, after reading the comment about electret microphones distorting at high sound levels, I experimentally moved the microphones out an inch or two, and the sound quality was much improved. So something was going on with the close mic placement, whatever it was. I suspect at least one microphone out of the 10 was frequently overloading and adding some unpleasant harmonics to the overall sound.

I decided the Limex mics were not compatible with my compact accordion, and I did not like the look of external mics, so I decided to look for something smaller that would fit better under the grill. I chose some of the tiny silicon-chip MEMS microphones, which are almost microscopic compared to an electret condenser capsule. I am pleased with the sound quality, so I will stick with those and not reinstall the Limex mics to try your suggested experiment. BTW, these are so small you can't easily solder or handle them directly. The ones I used came pre-soldered to small printed circuit boards.

I followed up on your suggestion and consulted my Limex MPR3 manuals. I do see the noise gate feature mentioned in the microphone controller manual. However, I did not purchase the microphone controller option, so I never paid much attention to this manual, as I presumed those features would not have been available to me. Limex is modular, and I purchased the "M" version without any front panel controllers.

I also reviewed the Limex PC Software manual. I see there are some microphone settings one can adjust using a computer, including some internal preamp gains. I never thought to experiment with these. I suppose it is possible the installer did not set these properly, and it could have been an internal gain staging problem. Well, too late now, as I do not want to revert back to the Limex microphones.

SeatleOwl, Miking accordions can be tricky, and there are a lot of systems, both external and internal, each with their pros and cons. I think your Titano PA will have more space behind the grill than my compact CBA, so you are unlikely to encounter the problems I had if you choose one of the internal mic systems.

 

[debra]

OK, I am starting to understand. I also am willing to bet that I know what caused this AND how to solve it (proper installation aside, because my mics were so close that on 3 notes I heard a "click" as the arm of the mechanism hit the mic, a simple thing to adjust in about 15 seconds).

When the mic capsule is so close that the pallet hits it (or just misses it) it will capture the note it hits very loudly and notes in between the mic capsules much less loudly. So the "spread" of the pickup will be very uneven. That is the most common issue with mics installed under the grille: uneven sound volume, varying a lot between notes.
And this cannot be adjusted in about 15 seconds... but requires rethinking the whole mic placement and perhaps even a change to the grille... (to allow the mics to be further away from the pallets.

 

[jozz]

Hi everyone! I’m new to the forum. I’ve had the same Titano accordion from the 1970’s for many years. I’ve increasingly been playing in clubs with bands, and I feel it’s time for me to get an accordion that plugs directly into a PA. I’ve done some research, and I think the best choice for me is to have installed something like the Harmonik AC501-HQ.

What I’m not sure about is if I should install it in my beloved Titano- the only accordion I’ve ever owned- or if I should get a second accordion. Are there any disadvantages to installing condenser mics to the inside of the accordion?

if this was your no1 instrument for years then go ahead and install them
they will not be in the way, but are handy when needed
disadvantage is there will be holes drilled, but once installed it looks clean
it will matter little if you spend $$$ on Harmonik or opt for a cheaper system, they will all have mostly the same results and minor differences will be lost in the rest of the amplified signal chain in a loud show

 

[debra]

...
it will matter little if you spend $$$ on Harmonik or opt for a cheaper system, they will all have mostly the same results and minor differences will be lost in the rest of the amplified signal chain in a loud show

That is indeed very true. I used the Microvox system for many years. It cost maybe 30% of what Harmonik costs and was external (on the outside of the grille and bass compartiment. It worked well. I also used a cheap 5+1 system from Carini for years (mounted under the grille) that cost maybe 20% of Harmonik and it also worked well. Now for my bass accordion I use the new 5+1 system (without the 1 as it's a bass accordion and has no bass side) from Caverna Eletrificações which costs about half of Harmonik and that too works very well. (I wanted to put that in my bayan but alas there wasn't enough room under the grille where the diagonal rods are that connect the register sliders to the transfer box (that connects outside to inside for the registers).
A big difference between systems is power consumption. If you use the mics a lot you might be best of with either a cheap system that uses very little power or with the most expensive (Harmonik) system with phantom power (the Galliano model).

 

[JerryPH]

When the mic capsule is so close that the pallet hits it (or just misses it) it will capture the note it hits very loudly and notes in between the mic capsules much less loudly. So the "spread" of the pickup will be very uneven. That is the most common issue with mics installed under the grille: uneven sound volume, varying a lot between notes.
And this cannot be adjusted in about 15 seconds... but requires rethinking the whole mic placement and perhaps even a change to the grille... (to allow the mics to be further away from the pallets.

I don't think you were completely understanding what I was saying.

The room under my grill is extremely tight. It was so tight that on 3 of the mics, they were being hit by the arm that connects to the pallet pad when you hit a particular note (not sure of the exact terminology). I had to physically move 3 of the mics SLIGHTLY to prevent it from tapping the microphone and causing it to make a sound heard as a click or thump when I hit any of those 3 notes when recording or using the mics (completely unheard when just playing without amplification). Yes, it did take me a whole 15 seconds to address... I no longer have that noise happening when I hit those 3 notes and it definitely did not take me longer than that to address.

The spread that you are talking about is an issue that is addressed (more or less) by increasing the number of mics within an area, and that is one of the reasons I like the Limex system (or any similar system) that has more than the usual 2-3 mics to cover that area under a typical full sized accordion grill. In my case it is 10 mics under that grill and that seems more than enough to have very even tones from the top to the bottom of the keyboard.

I was once thinking to make a system (and still may), that uses 20 or 30 mics just for the fun of trying and learning. Electret mics are incredibly affordable on popular Asian websites, so the difference between a 10 mic system and a 40 mic system for hobby purposes, is under $50cdn.

 

[debra]

I don't think you were completely understanding what I was saying.

The room under my grill is extremely tight. It was so tight that on 3 of the mics, they were being hit by the arm that connects to the pallet pad when you hit a particular note (not sure of the exact terminology). I had to physically move 3 of the mics SLIGHTLY to prevent it from tapping the microphone and causing it to make a sound heard as a click or thump when I hit any of those 3 notes when recording or using the mics (completely unheard when just playing without amplification). Yes, it did take me a whole 15 seconds to address... I no longer have that noise happening when I hit those 3 notes and it definitely did not take me longer than that to address.

The spread that you are talking about is an issue that is addressed (more or less) by increasing the number of mics within an area, and that is one of the reasons I like the Limex system (or any similar system) that has more than the usual 2-3 mics to cover that area under a typical full sized accordion grill. In my case it is 10 mics under that grill and that seems more than enough to have very even tones from the top to the bottom of the keyboard.

I was once thinking to make a system (and still may), that uses 20 or 30 mics just for the fun of trying and learning. Electret mics are incredibly affordable on popular Asian websites, so the difference between a 10 mic system and a 40 mic system for hobby purposes, is under $50cdn.

I did understand what you were saying. Yes it only takes a few seconds to make sure the pallets do not actually hit the microphones. But with distances so tight the spread is going to be pretty bad. Decent systems use 5 or 6 mics in one line, which is good enough for non-cassotto accordions if you have something like an inch of distance between the pallets and the grille. For cassotto instruments you need another 5 mics in one line to capture the cassotto and be able to hopefully also adjust the balance between the volume of the reed banks in cassotto versus the reed banks outside.
Capturing the sound of an accordion with mics is generally a balancing act between the mics being as far away as possible, to have good spread, and the mics being close enough to avoid feedback from speakers. The latter is not a problem when you are just recording. But of course the best recordings are done with external mics a few feet from the accordion. I have been using the Microvox system for performances (the bar with mics mounted about an inch away from the grille, on the outside, and that gives good spread and not much feedback. For recordings (at home) I use a pair of AKG C214 mics and a Tascam digital recorder.

 

[JerryPH]

When I was using the Limex microphones for several years, it did not sound obviously distorted, but it was not a pleasant, natural accordion sound, adequate, but not that good. It took some time to reach this opinion, and by then my installer had gone out of business. I experimented with EQ, and tried other amps, but could not find any combination that sounded satisfactory. Then, after reading the comment about electret microphones distorting at high sound levels, I experimentally moved the microphones out an inch or two, and the sound quality was much improved. So something was going on with the close mic placement, whatever it was. I suspect at least one microphone out of the 10 was frequently overloading and adding some unpleasant harmonics to the overall sound.

Got it, that would fall under the category of a hardware issue and not with the concept of overloading. One of the electret mics was simply defective. If it was overloading, all 10 mics would be doing the same thing, not 1 out of 10. You can tell that there are no issues with the mics in my video about my Beltuna.

Now, I just learned something new from you... we are using the same version of Limex MIDI, but I have the MC10 front panel controller, and honestly did not even know that a system would work without it. The option is called NIOISE GATE. From the manual:

"When NOISE GATE is activated, the microphones can then only be turned on (independent of the treble or bass side) when you press a key. This allows you to work with very high micro- phone volumes (close to the feedback limit), which is especially useful for rock music.
NOISE GATE also helps suppress unwanted feedback noise, which could be broadcast through your microphone system during rests or breaks in the music."

Limex is certainly new to me starting with this accordion, and they are neither easy to communicate with or find clear info on... both of which are likely why they are not as popular as they could be.

I decided the Limex mics were not compatible with my compact accordion

It did not come to mind to try to find out which of the 10 mics was defective and simply replace it?

I did not like the look of external mics

I too hate the look of external mics, especially the gooseneck ones!
Glad you found what you liked. I'll look in to the silicon mics, sounds interesting.

 

[SteveBox]

It did not come to mind to try to find out which of the 10 mics was defective and simply replace it?

I did not make myself clear. I was trying to say I suspected that at any given time, one or more microphones out of the 10 might have been overloading if that microphone happened to be right next to the pallet of a note I was playing. The mic(s) that was/were overloading would vary, depending on what notes I was playing. This is only a theory.

As I think about this more, it may have been an internal gain staging problem. Having reviewed the manual, I learned that there are internal pre-amp gain settings for the microphones. Maybe the mics were not overloading, but being closer to the sound source than normal, the pre-amp gains should have been lower.

Regardless of the cause, the main reason I decided to replace the Limex microphone system was that it seemed obvious that having to nestle the microphones between pallets could not possibly result in good sound quality. Also, I did not like the digital noise in the audio that I could clearly hear when not playing.

To my knowledge, nobody is making an accordion microphone system using silicone mics. I think they have possibilities, but you will need electronics knowledge to do it yourself. There are many on the market, and not all are suitable for a low noise, high fidelity application. The technology keeps advancing, and only just recently, a manufacturer has introduced the first one with a directional cardioid polar pattern,

 

[JerryPH]

To my knowledge, nobody is making an accordion microphone system using silicone mics. I think they have possibilities, but you will need electronics knowledge to do it yourself. There are many on the market, and not all are suitable for a low noise, high fidelity application. The technology keeps advancing, and only just recently, a manufacturer has introduced the first one with a directional cardioid polar pattern,

Interesting, thank-you. Have a link to that manufacturer?

 

[SteveBox]

Interesting, thank-you. Have a link to that manufacturer?

ICS-40800 | TDK InvenSense

The ICS-40800 is an ultra-low noise, analog output, dual-ported MEMS microphone. The ICS-40800 includes a MEMS microphone element, an impedance converter, and an output amplifier. The ICS-40800 is constructed from two sound ports, located on the bottom and top of the assembly. The dual port...

invensense.tdk.com

https://invensense.tdk.com/wp-content/uploads/2021/02/DS-000245-ICS-40800-Datasheet-Analog-Directional-Microphone-v2.0.pdf

These are extremely tiny, as are all silicon microphones. You can't just attach wires to them as you would a normal microphone capsule. They require soldering to a PCB board using surface mount techniques. Some of these microphones can be purchased pre-soldered to an evaluation board, but I don't see this currently offered for this model.

 

[JerryPH]

Thank-you!

 

[SeattleOwl]

if this was your no1 instrument for years then go ahead and install them
they will not be in the way, but are handy when needed
disadvantage is there will be holes drilled, but once installed it looks clean
it will matter little if you spend $$$ on Harmonik or opt for a cheaper system, they will all have mostly the same results and minor differences will be lost in the rest of the amplified signal chain in a loud show

Okay, that’s helpful. Thank you!

 

[SeattleOwl]

A big difference between systems is power consumption. If you use the mics a lot you might be best of with either a cheap system that uses very little power or with the most expensive (Harmonik) system with phantom power (the Galliano model).

Ooh, that’s something I hadn’t considered. Thank you!

 

[debra]

Ooh, that’s something I hadn’t considered. Thank you!

I have worked mostly with mics inside bass accordions. (Great thing about them is that everything can be placed under the grille, so no holes to drill towards the bass side as a bass accordion has no bass side, only a treble side with low notes.)
Most mic systems there have a 9V battery that lasts for years. You need to remove the grille to get access to the battery to replace it. Some players just go on for years and years without even knowing there is a battery and are then surprised the mics stop working and they think they are broken... New mic systems often come with a "box" for the battery, with a lid, and that makes the battery very easy to replace (or charge and put back). They have that easy access to the battery because you need it frequently as their 9V battery doesn't last very long.
In my bass accordion the 9V battery for my new mic system can go for about a month at the most. I removed it and installed 6 AAA batteries instead, which should keep me going for about half a year. I may replace that as well as I can find just enough room for 6 AA batteries that should last probably two years.
Older battery systems only used the battery to supply a phantom current to the mic capsules and were otherwise passive. New mic systems have more active electronics for stronger output, tone control, power indicator led,... and all of that causes the system to use a lot more power.

 

[Alan Polivka]

To me mics that are under the grille are internal. They require some "disassembly" to reach them.
When mics are mounted on the outside of the grille I call them external. The Microvox mics I have used for many years (and still occasionally use) are placed on the outside of the grille (or bass compartiment) using velcro. Note the word "outside", so they are external.
A mic that's installed inside the accordion on a reed block is the absolute best solution to avoid unwanted sound feedback, but is also the absolute worst solution to capture the sound that comes out of the accordion.
In the past bass accordions were often fitted with an internal microphone, inside the bellows. They invariably produce a horrible sound.

The "horrible sound" was likely due to them being the older, crystal mics ... not because of the location. Yes, the sound is different inside the bellows than outside, but I wouldn't call it horrible. In fact, I find the sound of a good (not crystal) internal mic to be pleasing in some ways.

 

[Alan Polivka]

Another advantage of an internal mic is that it can produce deeper bass than the same mic located outside the bellows in the LH side of the accordion.

disadvantages:
- complete stereo separation pretty much impossible
- bad install susceptible to leaks

advantages:
- single "omni" mic needed to capture both hands
- much reduced chance of feedback due to being hidden from ambient noise
- lower cost for the hardware since less is needed

My Morino has a single internal mic... works well. My Beltuna has separate stereo setup. For public performances stereo is less of an issue if you are playing for someone else and easier to set up. Home recordings highly benefit from a stereo setup with individual controls, the end results are far superio

disadvantages:
- complete stereo separation pretty much impossible
- bad install susceptible to leaks

advantages:
- single "omni" mic needed to capture both hands
- much reduced chance of feedback due to being hidden from ambient noise
- lower cost for the hardware since less is needed

My Morino has a single internal mic... works well. My Beltuna has separate stereo setup. For public performances stereo is less of an issue if you are playing for someone else and easier to set up. Home recordings highly benefit from a stereo setup with individual controls, the end results are far superior.

 

[Alan Polivka]

disadvantages:
- complete stereo separation pretty much impossible
- bad install susceptible to leaks

advantages:
- single "omni" mic needed to capture both hands
- much reduced chance of feedback due to being hidden from ambient noise
- lower cost for the hardware since less is needed

My Morino has a single internal mic... works well. My Beltuna has separate stereo setup. For public performances stereo is less of an issue if you are playing for someone else and easier to set up. Home recordings highly benefit from a stereo setup with individual controls, the end results are far superior.

One issue with putting electret condenser mics inside an accordion (inside the bellows) is that most (but not all) electret condenser mics are pressure-sensitive. This results in a shift in in DC bias on the output when bellows direction is changed. Some amplifiers can tolerate that but many cannot. Reducing the decoupling capacitance reduces the duration of the transient bias shift, but also reduces the depth of bass passed on to the amplifier. Another solution is to find an electret condenser mic that is not pressure sensitive. Some Sennheisers are not.

Hey Terry, with pleasure. The only 2 things to watch for are to not place the mic on anything that can transmit a lot of vibrations in to the mic and to be super careful of air leaks. Because the mic is contained within the "bellows area" it captures the left and right hands easily enough even with large bellows like on my Morino VI N.

A picture is worth a thousand words... lol:

Factory original. This dead mic was replaced with a mic cabsule from another mic


Remove the factory mic. This rubber part came from Hohner. If possible I would suggest a little DIY and creating something similar:


This is the mic capsule from a mic I had laying around:


Once installed:


From the factory, there is a plug that is air-tight and that the factory connector/cable clamps on to:


You would need to drill in to the area that is accessible inside the case or drill from under the grill in to the inner case to pass the wire in and use a bit of good silicone to seal the hole on both sides and then drill a hole in the grill to which you could attach the plug to. Since you are talking MONO, a single 1/4" female mono plug is all that gets placed on the accordion.

To get it working on an amp this is all that you would need, however the output is low if you want to record from this, so an external pre-amp makes all the difference. There are a ton of options out there, but I use this and it works great!:





Hope that helps some!

It is stated above: "to not place the mic on anything that can transmit a lot of vibrations in to the mic". That is indeed the approach taken by many (but not all) installers of internal mics. However, if you want really deep bass, do mount the mic directly to a reed block or to the accordion body, to intentionally capture the vibrations.