Need advice for improving isolation in miking a string bass live on stage. Jazz mostly

[murrayatuptown]

For 'scale', the polymer piezo ribbon I used was about 11000 pF, and roughly 20 mm wide by 130-140 mm long.

It's Achille's Heel is that it is heat-intolerant so you buy them with riveted wire connections and solder to the wires.

They also need protection against being creased. 3/16" cotton webbing and more cloth over it was bad beginner's luck but it worked for years until I retired it.

 

[murrayatuptown]

For 'scale', the polymer piezo ribbon I used was about 11000 pF, and roughly 20 mm wide by 130-140 mm long.

It's Achille's Heel is that it is heat-intolerant so you buy them with riveted wire connections and solder to the wires.

They also need protection against being creased. 3/16" cotton webbing and more cloth over it was bad beginner's luck but it worked for years until I retired it.

Finnish company Emfit owns B-Band musical instrument pickup subsidiary. They use electret ribbon made by Emfit that is sometimes called 'pseudo-piezo'.

The two different materials are treated polymers so there is some similarity but many differences.

They were rather unfriendly to deal with. I bought a roll of their electret material that was a remnant of a designer's kit that had many other forms of no use to me. It's a foamed PVDF material that is treated. It bore little resemblance to the catalog description but worked.

When I started identifying differences in construction observed by x-ray inspection they responded that the designer's kit contains a wide variety of materials...they make many custom types. Most applications are industrial scientific & healthcare oriented, other than the B-Band guitar & bass products.

The foamed dielectric is roughly 1/10 the density of the piezo ribbon and 10x the impedance. Their proprietary preamps were somewhere in the 40-50 Megohm input impedance range with careful management of Johnson noise.

The piezo ribbon was made by Measurement Specialties who has since been acquired by someone else. MSI name just came back to me - that's why I didn't mention them previously. When I bought them, there were many varieties that were easily purchased from multiple sources at modest prices, and they are more easily used. The app. engr did warn me there were many patents to avoid, but commercialization was not my goal.

 

[rock soderstrom]

A baffle behind a cardioid makes it more directional. Only actually sealing off the mic's rear vents makes it (a poor) omni.

A bit off topic, what is poor about operating a cardioid capsule without rear vents. The directivity or the general performance of the microphone?

Here an example mock-up of the well-known KK12 capsule without rear vents. (please ignore the missing grille). What does this really change?

 

[k brown]

It will undoubtably be omnidirectional; it is, however in almost all cases deleterious to the frequency response.

Capsules such as the Sony C37A and Schoeps MK5 are designed to have reasonably flat response with their rear vents blocked for omni, but most are not.

@kingkorg has had good results with, I believe this very capsule, but (I believe) by sealing the backplates internally - not by just blocking the vents 'externally'.

A top Classical engineer has recommended to me to tape off part of the vents of an SDC cardioid to achieve subcardioid (works better with some capsules than others), but that's a far cry from completely blocking them to get omni.

His exact quote: "I use Rode NT6's from time to time and I stick some insulating tape around the bottommost opening of the back chamber of the capsule. This is the sort of thing I would hesitate to publish on Gearslutz because the world and his wife would give me a hard time, but it is worth trying. The Schoeps MK5 capsule is switchable mechanically between cardioid and omni and this is achieved by shutting off the rear chamber when you want omni - I figured you could try something similar with sticky tape to achieve an intermediate pattern."

 

[k brown]

@kingkorg conducted this experiment:

DIY M50 capsule

So, i found some info on m50 capsules. One of recent versions is basically km84 omni type capsule, which is again fairly simmilar to chinese SDC capsules. Rode made Faulkner series m50 type mic which has the same backplate as chinese ones. Plastic backplate is sealed for omni, so i sealed mine...

groupdiy.com

Maybe he can provide an update ; - )

 

[rock soderstrom]

Thanks a lot Mr. Brown! That's a lot of interesting info. I'll have to try that out, I think I'll build MicUlli's FET SDC circuit for it.
Then I can also compare this en passant against my Sela tube clone with the same capsules. Exciting.

however in almost all cases deleterious to the frequency response.

Is it possible to estimate which frequency ranges are affected and how?

 

[rock soderstrom]

@kingkorg conducted this experiment:

DIY M50 capsule

So, i found some info on m50 capsules. One of recent versions is basically km84 omni type capsule, which is again fairly simmilar to chinese SDC capsules. Rode made Faulkner series m50 type mic which has the same backplate as chinese ones. Plastic backplate is sealed for omni, so i sealed mine...

groupdiy.com

Maybe he can provide an update ; - )

Thanks

 

[k brown]

Interesting vid on using bleed to advantage:

https://gearspace.com/board/remote-possibilities-in-recording-amp-production/1406049-masterclass-record-acoustic-music-use-crosstalk-create-room.html

 

[Mr. Moscode]

It's been a while since I've been online for this thread.
First of all thank you for help.
I have a number of recorded tracks but have not had the time to audition them. but I will. What I have heard is my ATM35 mic in the bass hanging from an F hole. It so far has the greatest rejection of the non bass sounds.

Will keep you posted when I can.
Thanks again.

 

[evil grill]

I tried all the tricks for double bass on stage for over the last 15 years...

There's always and always, too much drums leakage on the Double Bass microphones.
Tried all the different polar patterns, positions...

The only thing that works is throwing a Lavalier microphone inside the Double bass through the F-Hole, I've used an Omni Lavalier but also a Cardioid both work well, don't care too much about position, just throw it inside.
A good Lavalier like the DPA 4060 helps, of course it will sound better than a cheaper miniature microphone.

Adding to this I also stick an AKG C411 inside the double bass also, this is a contact condenser omni microphone but you stick it to wood like you would do on a Piezo pickup. Goes through the F-Hole also, and I stick it in the inside wood.

I use a mix between 3 recorded tracks the Lavalier, the C411 and the Pickup/DI.

The pickup/DI track might go in the mixing stage through the UAD "Woodworks" plugin which does wonders, it brings back some "Wood" sound to Piezo tracks. I might also use TC Electronics "Bodyrez" pedal. Both Woodworks and Bodyrez improve the sound captured from Piezo pickups

In a seminar I visited Bruce Swedien talked about putting a mike inside the bass for a recording of a legendary jazz band I can't remember the name of.
I've tried this with an Eartworks TC30k on an acoustic jumbo bass guitar. Worked very good.

'Drummer's knee' (sometimes called 'crotch') is a way of minimally mic'ing a drum set. An omni in front of the kit, usually on the floor tom side, at approx the height of the drummer's knee. Often can give fairly good balance of the whole kit; sometimes with a kick mic added.

The Crown SASS demo CD had drum tracks recorded with just the SASS in this position, plus kick mic.

https://gearspace.com/board/so-much-gear-so-little-time/1182345-favorite-quot-knee-quot-mic-recording-drums.html

Done this with Eartworks TC30k and it sounded awesome with minimal bleed from the rest of the loud band.

 

[AlgoRhythms]

I'm gonna suggest something that seems contradictory to what's normally done. I've successfully recorded many of the most famous jazz bass players in history, both live on stage and in the studio, and this has worked well for me.

I suggest trying a small diaphragm condenser mic like a Neumann KM83, suspended with rubber bands in the bridge. (Don't use foam as this chokes the bridge and the bass won't sing.)

Yes, this is a OMNI mic, NOT a cardoid. I'm not a big fan of cardoid mics (or figure 8) mics on bass because they always exaggerate the low end due to proximity effect. I find that I have to roll off this boost to get a natural bass sound. A good bass player with a good sound won't need any additional bass boost, from proximity effect or EQ.

Omni mics don't have proximity effect. The sound more natural when micing everything close. The KN83 has a very smooth off axis response, pretty even across the whole frequency spectrum, with a bit of attenuation, making any leakage sound less colored than the typical off axis response of a cardoid.

Also, having the mic so close to the body and strings let's you take advantage of the 3:1 rule. Leakage energy will be 1/9th as strong as the primary source.

In most jass recordings, there will almost always have leakage because there are usually no overdubs for the bass and everyone prefers to be physically close for better communication. This leakage can be your friend IF it's lower in level AND sounds natural.

I suggest giving this a try. Be sure to have everyone closer rather than spread far apart. And try to have the bass player position his back and the back of the bass to the most offending leakage source.

 

[k brown]

I'm gonna suggest something that seems contradictory to what's normally done. I've successfully recorded many of the most famous jazz bass players in history, both live on stage and in the studio, and this has worked well for me.

I suggest trying a small diaphragm condenser mic like a Neumann KM83, suspended with rubber bands in the bridge. (Don't use foam as this chokes the bridge and the bass won't sing.)

Yes, this is a OMNI mic, NOT a cardoid. I'm not a big fan of cardoid mics (or figure 8) mics on bass because they always exaggerate the low end due to proximity effect. I find that I have to roll off this boost to get a natural bass sound. A good bass player with a good sound won't need any additional bass boost, from proximity effect or EQ.

Omni mics don't have proximity effect. The sound more natural when micing everything close. The KN83 has a very smooth off axis response, pretty even across the whole frequency spectrum, with a bit of attenuation, making any leakage sound less colored than the typical off axis response of a cardoid.

Also, having the mic so close to the body and strings let's you take advantage of the 3:1 rule. Leakage energy will be 1/9th as strong as the primary source.

In most jass recordings, there will almost always have leakage because there are usually no overdubs for the bass and everyone prefers to be physically close for better communication. This leakage can be your friend IF it's lower in level AND sounds natural.

I suggest giving this a try. Be sure to have everyone closer rather than spread far apart. And try to have the bass player position his back and the back of the bass to the most offending leakage source.

+100 !

 

[nick_t]

k brown: "An omni in front of the kit, usually on the floor tom side, at approx the height of the drummer's knee. Often can give fairly good balance of the whole kit."

No disagreement with this, it works well. But will just add it's not particularly important for it to be omni. Any mic with good off-axis response will work fine (EVs, 441 etc). The mic is being placed central to all drums. The trick is to point it at the drummer's crotch, not at any one drum. That way all drums are roughly at 90 degrees, and level and freq response will remain even.

 

[motoindo]

While not playing any instruments myself or having been involved in recording and thus being a complete noob in this matter I understand the problem is with "secondary" sounds (bleed) polluting the "main" instumental signal ? Isn't this what these noise cancelling headsets do ? I've searched this thread for the term without finding any so here goes ....

What if you would take 2 signals, one with a high bleed content facing away from the bass (a) and one inside the bass (b) and subtract a from b ? As long as both a & b mics are close and the bleed spectrum remains low in frequency - drums ? - you might be able to reach some significant cancelation before phase issues spoil the subtraction process ?

Again, apologies in advance if this is bollocks and/or already tried before without joy, very new here.

 

[EarthTone]

I've done a lot of live recordings over the years of jazz bassists. I can tell you where I've wound up:

This mic was recommended to me by a great NYC bassist for live recordings and sounds amazing on close mic-ing bass. I've even used it in the studio as an extra source on the acoustic bass when everyone's in the same room. It's cheap but it doesn't have the high frequency boost their more expensive version has so it actually sounds better on bass than their more expensive model: https://www.amazon.com/Audio-Technica-Cardioid-Condenser-Instrument-Microphone/dp/B000K67VG0/ref=sr_1_2?crid=295VVFTR2KT8X&keywords=atm350+mic&qid=1685914162&s=musical-instruments&sprefix=atm350+mic,mi,65&sr=1-2&ufe=app_do:amzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0

On the recording below I used:

1. R84 ribbon placed in front of the strings with the player positioned so that drums were in the null

2. Close clamped SDC, schoeps cardioid style transformerless DIY build, aimed between the bridge and the F hole right up against the wood but not touching

3. M88 close mic-ed. Didn't sound amazing but added some nice low end.

A blend of those three signals worked. I found out about the ATM-Pro35 after this record date. Otherwise I would've used that.

In the studio is a whole different animal. Ribbon or U47 tube a foot ro two off the bridge usually sounds great. But that's only if you are in isolation.

Matt

Recording of my trio, players all in the same room, to demonstrate the mics listed above in context:

matt marantz sonoran - Google Search