Fig-8 with Bass!

Basically all I want is a fig 8 microphone with some real quality bass response.. I rented some schoeps SDC and they didnt cut the mustard for bass at all. The sennheiser mkh30 is better but I found the tonality a little dull or something.
I contacted one famous designer personally and he told me that stupid ol' physics is the deciding factor on the capsule response, which is true, he postulated that ribbon bass response (like my great Coles 4038) might be due to transformer added bass alongside a darkening of the capsule which naturally means that the preamp will create a bass heavy response.
I contacted another designer who said that the M49 had bass that could be modded up to -3db at around 8hz (his words not mine and this contradicts the official literature.) This is a front and back capsule design of course and he had a hand in the design of microphones for a famous audiophile world music label that operated during the 80s/90s, with fabulous bass,
So whats the trick?

If I'm reading you correctly, you are looking for a condenser mic, not a ribbon mic, that has good Fig-8 bass response.
I suppose the easiest way to accomplish what you would like is to modify the EQ portion of an existing, minimalist, transformer-based FET-based circuit. Maybe a single capacitor change will open up the bottom end for you.

Why fig8 - and what do you mean by "real quality bass response"

Please explain and quantify - otherwize there's to much guesswork involved.

Jakob E.

When you look at the various polar pattern frequency plots (within a mic system), figure eight does roll off the lows a little more (and more than a little way down low).
On the other hand it has some serious proximity effect. So at close  distances it will be bassy indeed.
And a ribbon mic like and RCA 44  (figure eight by nature) at close distances is bassier than most can handle.

I'm talking quantity of bass here, mind.
Yes, I too would like to know what you mean by "real quality bass response". If you mean it should pick up really low notes, then no  pressure gradient mic will cut it. For that you need a pressure mic. As a rule (not counting the oddballs) this will be an SDC with omni capsule.

Even then 8Hz will be a stretch.
In any case a pressure gradient won't do, least of all a figure eight.
Unless it's immune to the laws of physics.

Great responses so far, so I should clarify...I'm looking for a blumlein microphone pair, the imaging of blumlein is fantastic,
but the bass response is usually lacking in comparison to any other pattern when used with SDC.

What is it about the RCA 44 that the proximity effect is so boosted? The Coles 4038 I have sounds full range  even at a distance of 1m, its frequency chart shows a fairly flat response down to 50hz or so.

So my options are:
-Create some sort of inline tilt via EQ or a transformer or something (could introduce phase issues?), between microphone and pre or between pre and recorder (my schoeps pair have actually been modified to have separated capsule voltage, power and signal pins, so either would actually be possible without having to block phantom)

-Find a capsule that actually has a decent bass response in figure 8  for whatever reason that work from 60v polarisation and adapt it to attach to the schoeps body (Water Lily Acoustics, who I was referring to, used a Pearl capsule).

-EQ in post (this is actually not a very good solution because I like to get the sound balanced in the room and the bass is an important part of that)

-buy some completely different microphone set (very expensive solution) / Settle with ribbon microphones

The inline EQ or finding another capsule is my favorite option because they are DIY solutions, but I'm not necessarily looking for a fast n easy option, I'm willing to spend months if not years researching a good solution...

Again (welcome BTW), what instruments will you be recording and what do you want the bass range to be like? Do you want (more) general oomph or do you want to capture really low notes (e.g. big pipe organ)? Or both?

And have you tried classic AB (two omni's) and/or MS with one omni rather than cardioid (the other mic being a figure eight, as always)?

Thanks for the welcome!
I don't really care about capturing 20hz sounds with obscene clarity or anything, because that's gonna be a fools errand, its just that a steep dip from 200hz down is not useful, an extension to be more or less flat to 50-60hz at perhaps 1 or 2 metres or so would be much more useful.  Recording folk and jazz.

OmniA-B is great in a lot of circumstances, but the clarity can be odd and stuff can wander instead of having firm placement. Omni M/S is great, but I like the focus of figure-8 as a flavor. There is a wide selection of great SDC omni only microphones (schoeps, sennheiser, geffel, neumann, sonodore, josephson), but few really good figure of 8 ones.

This is from README.doc in my Yahoo MicBuilders Files which has more detail and explanations of fig-8 bass response.  You have to join

LEE'S CHINESE LAUNDRY LIST
from " a real beach bum who used to design Soundfield and other mics for Calrec " using half remembered measurements of loadsa mikes in the dim & distant past, crystal ball stuff from the magic internet and some new fangled digital measurements from a few 21st century wizards. 

In order of LF

Core Sound TetraMic
in my biased opinion, the best mike of the 21st Century.  In theory slightly more extended than a Soundfield Mk4 though in practice you'd be pushed to find anything which shows the difference.  Flatter responses and more consistent polar patterns cos sophisticated Digital EQ and alignment. www.core-sound.com

Soundfield Mk4
in my biased opinion, the best mike of the 20th Century.  Flat to 27 Hz in all modes.  A better omni than a 1/2" B&K bla bla .. 

Extended velocity response doesn't come for free but you get loadsa extras like a seismograph and underground trains and doors slamming and air-conditioning and wind and distant thunder detector ..

Except for the Schoeps & Sennheiser, the following are rather large for Blumlein vertical coincidence.

STC 4038 ribbon
Classic.  Still a very good mike with LF response better than all modern fig-of-8s except Soundfield & TetraMic. See BBC Engineering Monograph No4

www.bbc.co.uk/rd/pubs/archive/pdffiles/monographs/

Royer SF12 & 24 ribbon
A real find.  Nearly as extended as the 4038.  Probably many of its well loved characteristics too. 
'Flat' 90 - 11k Hz  -5dB 30Hz 2m
-8dB 30 Hz w/o proximity.  4dB tilt 100 - 10k Hz.    -17dB(?) 20kHz

Sennheiser MKH 800
Very quiet.  MKH80 & probably MKH30 should be similar

AKG 414
Not flat but who cares.  The "voice" of the BBC.  Latest FET mikes very quiet.
Neumann SM69?
About the same extension.  These 2 mikes are double diaphragm LDCs so revert to omni at LF.  ie they cheat.  A couple of Shure papers in Files/Theory explain this.

Studio Projects B3 & C3
Cheap.  Charles Repka says, "superior LF to Speiden / Royer mic"
LSD2 Stereo version www.studioprojectsusa.com/

Schoeps MK8
still one of my favourites.  Obvious bass roll-off.  Worth correcting for its other virtues.
__________________

The 50Hz (free field) line is around the AKG414/Neumann SM69 mark.  These 2 mikes aren't flat but a bit bumped.

It's VERY difficult to do good LF measurements on Fig-8 mikes.  An anechoic good to 20 Hz for omnis is usually only good to 200Hz for fig-8s.

Measurements aside, in fact your "flat to 50-60Hz at 1 or 2 m." isn't actually 'possible' because proximity at 1m starts boosting bass from 50Hz so the acoustic response flattens out.
__________________

BTW, the main Blumlein pair in the Royal Albert Hall used to record the Promenade Concerts was originally a pair of 4038s .. then an AKG C24 (which was developed specially for the BBC) .. than a Soundfield Mk3A.

Angus McKenzie reported on FM broadcasts monthly in HFN and details the fuss when each of these changes were made.  Promenaders were (are?) very conservative.

IMHO, the Prom broadcasts are (still) some of the best music & sound available to the public via ANY medium.

dlozanothornton said:

Thanks for the welcome!
I don't really care about capturing 20hz sounds with obscene clarity or anything, because that's gonna be a fools errand, its just that a steep dip from 200hz down is not useful, an extension to be more or less flat to 50-60hz at perhaps 1 or 2 metres or so would be much more useful.  Recording folk and jazz.

OmniA-B is great in a lot of circumstances, but the clarity can be odd and stuff can wander instead of having firm placement. Omni M/S is great, but I like the focus of figure-8 as a flavor. There is a wide selection of great SDC omni only microphones (schoeps, sennheiser, geffel, neumann, sonodore, josephson), but few really good figure of 8 ones.

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OK, much clearer now. 

But the problem remains. That is, you want to use pressure gradient mics, used at a distance, but without bass roll off. Again, altering the laws of physics is somewhat tricky.
And boosting what's "lacking" will introduce quite a bit of noise and such.

Go in as close as you can (but I can imagine you don't want to lose the wider view).
An option may be to use a third mic as support. But do watch for phase issues.

Wiser guys than I may chime in now.   

thanks people! Ricardo, this information is really good, here is a direct link to the bbc paper quoted for anyone reading in the future: http://downloads.bbc.co.uk/rd/pubs/reports/1956-29.pdf
It does not mention why the bass response is better, but a very interesting read.
The fact that the person quoted mentions the fact that twin diaphragm capsules are omnidirectional at bass is interesting, the Water Lily acoustics capsule is double sided, so that could be a factor in their natural bass sound. I like the fact that he lists the 4038 and the MK8 that I was comparing as polar opposites, bass-wise..
I can get another 4038, but ribbons aren't as accurate to room information. Furthermore, the weight and mic stand requirements, alongside the possibility of ribbon damage would be ludicrous.

Fellow member Marik makes superb ribbon mics.
How about this one?
http://www.samaraudiodesign.com/VL373.html

dlozanothornton said:

I can get another 4038, but ribbons aren't as accurate to room information. Furthermore, the weight and mic stand requirements, alongside the possibility of ribbon damage would be ludicrous.

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There are definitely lighter ribbon mics that don't require hefty mic stands. Check out the Royer ribbon mics, especially their all-in-one Blumlein stereo mics. They seem pretty accurate to room info to me, but perhaps your requirements are far more stringent than mine.

And if cost of the mic is an issue, there is always the DIY option.  Here is Austin Microphone's DIY all-in-one Blumlein mic:

https://www.youtube.com/watch?v=X3mI59vJris

If I ever get around to building a DIY Jensen Twin-Servo-style preamp, I'll immediately build one of the Austin Blumlein mics. As it stands, my current preamp can't run a ribbon mic properly.

Also, for heavy mics I recommend using Manfrotto 420B long-boom tripods for studio light fixtures as mic stands. You can often buy them for around $80 used on ebay including the sandbag. They include a little brass spigot that has one end the same thread as European mic stands. No chance of your expensive mic taking a nosedive with the ultra-wide legs, which of course can be sand-bagged too.

I have two 420Bs for drum overheads, each with a heavy D-87 build. With this setup I could do Blumlein fairly easily.

dlozanothornton said:

http://downloads.bbc.co.uk/rd/pubs/reports/1956-29.pdf
It does not mention why the bass response is better,

Click to expand...

You need a bit more basic knowledge of mike design & physics to understand the BBC paper or the Shure papers.

Neumann have an excellent PDF book on their website.  It is the ONLY accurate & useful textbook on microphone design.  Very readable.  Please email me if you find another.

http://www.neumann.com/?lang=en&id=company_publications_mic_book

When 4038 was designed, it was the most extended LF mike in the BBC inventory.  Only 2 modern fig-8 mikes have more extension (and they both cheat  )

The fact that the person quoted mentions the fact that twin diaphragm capsules are omnidirectional at bass is interesting,

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That's me.

I can get another 4038, but ribbons aren't as accurate to room information.

Click to expand...

A good Blumlein mike MUST have accurate response to the room sound.  Peter Craven, one of the inventors of the tetrahedral soundfield mike said that only 2 'stereo' mike arrangements pick up the room sound properly.

One is 2 coincident omnis (not very stereo)

The other is crossed fig-8s.  Of course mikes are not perfect so its rare to find this.  But John Atkinson was surprised to find exactly this when he tried out a Soundfield Mk4 for the first time.

A 4038 is a good Blumlein mike BECAUSE it is accurate to room info ... better than many 'modern' mikes.  I think either Sheffield Labs or Telarc have built up a serious reputation with 4038 and consider it the best ribbon of the 20th Century.  I think only Marik's stuff rivals it in the 21st century.

The main con with a 4038 is your S/N will be 10dB worse than most modern mikes.  My MicBuilders Files also have a near SOTA noise preamp you can build for under $100 specially for ribbons like 4038.

Instead of more copies of RCA ribbons, I wish someone would make a 4038 with 10dB better S/N.

So you want subsonic bass to be picked up louder in your fig-8 microphone in a MS setup.

Have you considered that 1) the fig-8 represents the S part of the sound field, and 2) that low frequencies has very little directional component, the lower, the smaller and last 3) even if you got a significant difference-signal down there, you would have no way to reproduce it, as speakers behave the same.

This is why elliptic filters can be applied invisibly, and why subwoofer is fine as singular.

Are you sure you have a real problem? (no offense meant)

Jakob E.

The replies and information given have been super helpful so far, thank you!

micaddict, I have been curious about Marik's mic, I want to hear more examples of it, but it does look good...

dchang0, one essence of the issue is that I don't use a car often, I am trying to create a very portable but very high quality setup for folk.
good links!

That ribbons respond differently to room information is not a real detraction to me, just a different quality/tool.

I agree with you ricardo, and the 4038 could be the only worthwhile solution available to me at this point. Ive downloaded this Neumann book to read, great info- as I say I don't mind taking a while at trying to understand this all... Am I roughly on the right track to understand that it is the relationship between the impedence of the ribbon and the transformer that is helping the bass response? Therefore could a suitable transformer relationship be found with a Schoeps MK8 that would generate such a response? Or could such a thing be done actively either? Id happily trade a bit of the high end for that, especially if it improved/maintained the noise weighting.

Jacob, I don't mean subsonic, I mean below 250hz (which is roughly the dropoff point of the Schoeps MK8). Omni M/S is great and all, but the placement of an  omni microphone is extremely different from a figure 8 and depending on the interaction with the room, one can work far better than the other, so its good to keep options open if they are possible.

I think to simplify what I am talking about, I'm either trying to find fig 8 capsules or ways of modifying the output of the MK8 to have better bass response straight to the recorder.

dlozanothornton said:

Am I roughly on the right track to understand that it is the relationship between the impedence of the ribbon and the transformer that is helping the bass response?

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No.  4038 has extended bass because it was designed to do so.

Therefore could a suitable transformer relationship be found with a Schoeps MK8 that would generate such a response? Or could such a thing be done actively either?

Click to expand...

README.doc in my Yahoo MicBuilders Files which has more detail and explanations of fig-8 bass response.  You have to join

Includes Dip Ing Wuttke's (Schoeps) recommendations as well as mine.

I think to simplify what I am talking about, I'm either trying to find fig 8 capsules or ways of modifying the output of the MK8 to have better bass response straight to the recorder.

Click to expand...

My MicBuilders Files includes a circuit to do this too as WM55Schoeps.gif ...

This is why elliptic filters can be applied invisibly, and why subwoofer is fine as singular.

Click to expand...

.. and the situations where this isn't true.

dlozanothornton said:

dchang0, one essence of the issue is that I don't use a car often, I am trying to create a very portable but very high quality setup for folk.
good links!

Click to expand...

If you ride the train often, I suggest still using tripods intended for photography camera or lighting setups, just ones that collapse to shorter in length. Photography manufacturers know that field photographers value portability, so there is a huge selection of sturdy but super-light tripods out there. You can easily find shoulder bags designed for carrying the tripod you pick too.

For instance, the Manfrotto 420B I have fits in a 44 inch Bogen padded tripod shoulder bag, and the detachable sandbag pouch folds flat when empty and fits in the single pocket on the outside of the bag. I can sling it over a shoulder behind my back and still have two hands free to carry other gear. When I arrive onsite, I grab heavy items like canned soup, bricks, or water bottles and put them in the detachable sandbag pouch, which then gets attached to the rear end of the boom.  I sometimes carry a second detachable sandbag pouch that I also fill with heavy items onsite and that I drape over the tripod's base.

You would probably be fine with a 3-stage tripod that collapses down to 36 inches. Add to it some clamps and micro booms or cross-bars, and you can mount two heavy mics on one single tripod (but the detachable sandbag pouch MUST be filled with enough counterweight). This is exactly what I did before I bought my second Manfrotto 420B--I used an X-Y crossbar clamped onto the boom of just one 420B.

In short, you don't want to be using microphone stands because they aren't designed as well as photography camera or lighting stands.

dlozanothornton said:

That ribbons respond differently to room information...

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Yes, they do and the main reason being their unique directivity pattern. That is, directivity is a function of the transducer size, meaning the smaller the size the wider directivity on high frequencies (that's why say, 3/4 tweeters have much wider sweet spot). Since the ribbon is only some .25" wide its pattern is remarkably wide up to very high frequencies in the horizontal plane, with very deep null at 90 degrees. No any condensers large or small can even closely match that. On the other hand their narrow pattern in the vertical plane can be used to a benefit of helping eliminating HF reflections from the floors, or low ceilings.

Another advantage of the ribbons is their superior what some engineers call "reach" (whatever it is)...

If you want to use a Blumlein then nothing can beat ribbons. One word of caution, if Blumlein is your primary use then I'd suggest looking at dedicated stereo ribbon, where special precautions were made to design it with the shortest possible distance between the motors. Otherwise, you'd get some phasing anomalies. That's why say, an older B&O BM5 (which I highly regard) always has some problems at some 4-5kHz range because of large distance between elements.

dlozanothornton said:

Am I roughly on the right track to understand that it is the relationship between the impedence of the ribbon and the transformer that is helping the bass response?

Click to expand...

Surely, those are connected, but usually, well designed ribbons have very carefully balanced amount of acoustical and electric loading. Any additional bass shaping (for example, to compensate for proximity effect) is usually done with reduced amount of inductance on the transformer's primary (and often, acoustical means).

The bass response in the ribbons is limited where the mass controlled system on low frequencies turns into resistance controlled (mainly because of air load and "springiness" of air in the gaps between ribbon and magnets), so the mechanism is totally different from say, double sided condenser capsule (for more info please read Shure article). But there are tricks to deal with that and the 4038 is a good example.

Best, M