If only two mics... ?

[k brown]

Here'e a cleaner, corrected schem.

I also crack off the SMD tant input cap and replace with a film cap (off the board).

 

[ricardo]

The imaging you get from AB omnis depends entirely on how far they are spaced, plus if, and how they are panned-in. Onno Scholtze shortly before he died was all ga ga about spacings as small as 10-12"; even on orchestra, but it's way too narrow a sound for my taste.

AB spacing any larger than about two feet is where the image get too diffuse, too wide, and a hole starts to open up in the middle. But a little panning-in restores the center perfectly. I've used 3' AB with about 80-82% pan-in with great results - no hole at all.

Can you please elaborate on this.

If I understand you correctly, you use spaced omnis about 2 ft apart but instead of panning them them hard L & R, you pan them slightly in.

Where do you point them?

Lest you fear that doing so would be a mess of combing, a version of the Decca Tree system that Kenneth Wilkinson, John Dunkerley and others in later days of the label, replaced the center triangle with a simple 3' AB pair that was panned-in 50%! With this setup, the level of the outriggers was a bit higher than with the trio of mains. Most of Dunkerley's Montreal recordings were done this way; I never heard a reviewer complain of comb filtering. I believe some of those Dutoit/Montreal releases won engineering Grammys. Also, the Classic Film Scores series on RCA conducted by Charles Gerhardt, engineered by Kenneth Wilkinson used this '4-mic Decca Tree'.

The 'combing' is part of the OOP sound that gives the 'airy' feeling with any spaced arrangement ... from ORTF to these spaced omnis.

The main con is mono compatibility where the 'combing' becomes most obvious & intrusive.

 

[k brown]

Can you please elaborate on this.

If I understand you correctly, you use spaced omnis about 2 ft apart but instead of panning them them hard L & R, you pan them slightly in.

Where do you point them?

The 'combing' is part of the OOP sound that gives the 'airy' feeling with any spaced arrangement ... from ORTF to these spaced omnis.

The main con is mono compatibility where the 'combing' becomes most obvious & intrusive.

I just follow the practice of Tony Faulkner, who uses 26" spaced SDC omnis on his 4-mic 'phased array', and they are aimed 90 degrees. He does the same when using the simple omni pair of M 50s : 26", aimed 90 degrees. Since I do so much of my listening on 'phones I find this spacing more pleasant when panned-in about 90-95%. This is preferable to simply moving the mics closer together as it retains the Interchannel Time Difference.

Is that what you wanted elaboration on?

_________

There's no combing with ORTF (or any other near-coincident pair); only a teensy bit when summed to mono.

Perhaps you're confusing interchannel phase differences (usually called Interchannel Time Difference (ITD) with combing. Stereo recordings with ITD only have combing when summed to mono.

Spaced techniques are not "out of phase"; that term referrs to signals that have a 180 degree phase (or polarity) difference, that will null when mixed together.

Spaced stereo is more accurately described as having 'low correlation"; whereas coincident techniques are 'fully correlated'. It is the low correlation that gives spaced stereo it's spacious, enveloping 'bloom', especially at low frequencies.

_________

I still don't understand the concern for mono compatibility; none of the major Classical labels used mono-compatible techniques (I guess it's arguable if one considers Chesky a 'major label' or not; they started with Blumlein, then went Soundfield, and lately binaural plus some ribbon Blumlein https://www.soundstagesolo.com/index.php/features/193-is-chesky-dumping-binaural).

Where is anyone hearing music in mono these days where they could really notice combing to any degree? - smartphones?, AM radio?

 

[mhelin]

Where is anyone hearing music in mono these days where they could really notice combing to any degree? - smartphones?, AM radio?

Most (under 300 EUR/$) portable bluetooth speakers which are the most sold speakers today are monophonic. Some of them sound pretty good, BTW, some can be configured as stereo pair if you own two of them (same model).

 

[k brown]

Most (under 300 EUR/$) portable bluetooth speakers which are the most sold speakers today are monophonic. Some of them sound pretty good, BTW, some can be configured as stereo pair if you own two of them (same model).

Most of the ones I've seen (i.e., Anker, Tribit) are stereo - two circuits to two drivers, so the inputs are not summed to mono; they can be paired with a second unit so that you can have two some distance apart.

Just having L/R drivers very close together doesn't comb anywhere near as much as summing L/R signals together to a single driver.

https://www.amazon.com/Anker-Soundc...&keywords=anker+speaker&qid=1735427280&sr=8-1
https://www.amazon.com/Tribit-XSoun...34&sprefix=tribit+speaker,aps,222&sr=8-3&th=1

 

[Migs 31]

Where is anyone hearing music in mono these days where they could really notice combing to any degree? - smartphones?

In some Hotel lobby’s, supermarkets/shopping centres, etc.

While doing my Christmas shopping at my local Carrefour supermarket, I noticed their speakers are connected in Mono. Resulting in a particular song producing some weird cancellation, due to phase issues

So... if only “two mics” make sure they are in Phase et al.

M

 

[pmfalcman]

Those who listen to music (and accept this quality) on portable bluetooth speakers will not notice or recognise combing if it were of garden rake magnitude.

As for supermarket music I'd welcome a 100% cancellation...
Especially during X-mas period...

 

[GeorgeToledo]

I spent years recording all kinds of things with a Mark 4 Soundfield -- radio theater, interviews, concerts, opera, a weekly pipe organ series -- when I was the production manager at KWMU-FM, St. Louis. It was a nice mic. but it didn't knock me out. And absolutely no one was listening to Ambisonics. When we first started broadcasting Ambisonic recordings, we held two listening parties for the station's audience, inviting them to come to a space we had prepared. We had a good turnout, and the sound was very convincing. The "walls" between the side speakers were almost palpable. But the technology didn't catch on with anyone. I almost went to work doing Ambisonics when Nigel Branwell was heading a new company that was going to promote Ambisonics in North America. Glad I didn't as the whole thing folded shortly before I gave my notice.

In my experience, surround is only useful for computer games, sporting events on video and movies. In my experience, the average person couldn't care less about surround sound. They listen to music on their phones, from their computers and from "hi-fi" systems with cheap speakers. And while technology is always improving, and that situation may be changing, surround sound for music enjoyment is essentially a non-starter for the average person. It is for the enthusiast and the person who invested in a home theater (and actually sets it up correctly).

Traditional stereo techniques are what I've used much more in the 50+ years I've been recording, and are what I see as likely for the near future. I am a fan of spaced microphones, but monaural compatibility can be a problem. I don't like X/Y or Blumlein, but will happily used them if the situation calls for it. X/Y is good for radio when monaural compatibility is required. M/S can be useful. ORTF is fine with me as it is a bit more colorful than X/Y, providing some time of arrival cues. Blumlein can be very hard to place in a reverberant environment as it picks up equally front and rear, so the stereo pair may have to be placed too close to the performers. In less reverberant environments it's fine.

I believe all these techniques can be very satisfying and I use whatever gets the job done. This said, I haven't even touched on binaural, or the use of Jeckln/Schneider discs.

I don't want to derail thls thread further with a discussion of surround sound or how my experience is not everyone's. I just wanted to relate my experience with surround and stereo mic'ing techniques. Thank you for reading this far.

I think the biggest problem with it is that humans likely evolved to perceive sounds situated at the rear as a threat. Even when it “sounds good”, it can be subtly agitating.

 

[k brown]

Could you provide your Okatva schem ? Maybe I would be tempted to warm the iron... I guess you deal with the +48v, don't you ? No battery... The capsule polar. can be done with +48v too as the original MK-012 (without DC/DC board)

Here is the Russell "Schoktava" schem. I don't know (I'm not enough experienced with electronics) if it's good, great, or just so-so. I've build up 2 boards but never tested them... I could be tempted to get 2 hyper caspules (brand new from their online german shop)

Sorry, I forgot the actual B1 Oktava schem you asked for. This connected to the schem shown in post #181.

 

[Emmathom]

Sorry, I forgot the actual B1 Oktava schem you asked for. This connected to the schem shown in post #181.

Thank you k brow.
Is it a kind of "SRPP arrangement" ?
I don't see neither a jfet gate R to ground... Strange arrangement (for me and my small experience)
I don't see neither any cap. to block DC so I guess there's a OPT in "the following box"

Please don't take it the wrong way but if one day I want to rebirth my Oktava's I will ask you (I can even ask ) for a complete schem. from capsule to XLR out because as it is now, cut in 2 or 3 schematics, it's hard for me to put the whole thing together...

 

[Paul W]

I think the biggest problem with it is that humans likely evolved to perceive sounds situated at the rear as a threat. Even when it “sounds good”, it can be subtly agitating.

Yes. Or just harder to visualize whatever you're visualizing in response to listening to the music, because it's not normal to visualize stuff behind you. For me at least it's more comfortable visualizing things more or less in front of me, and sounds from behind are oddly distracting.

For me there's also the problem that I don't sit still in one perfect place to listen to music. I can arrange my space & stereo speakers so that I can move around a bit without the stereo getting way out whack, but surround speakers are hopeless... I'm often too close to one surround speaker and too far from others.

My friends' home theater systems are mostly the same way, even sitting still for a whole movie. They don't have very big rooms, and the sweet spot is small because the side speakers are too close. It's fine for one or two people sitting in the little sweet spot, but when they invite others over, most people are sitting way too close to one surround speaker and too far from others. (3-stereo is much more forgiving.)

 

[k brown]

Thank you k brow.
Is it a kind of "SRPP arrangement" ?
I don't see neither a jfet gate R to ground... Strange arrangement (for me and my small experience)
I don't see neither any cap. to block DC so I guess there's a OPT in "the following box"

Please don't take it the wrong way but if one day I want to rebirth my Oktava's I will ask you (I can even ask ) for a complete schem. from capsule to XLR out because as it is now, cut in 2 or 3 schematics, it's hard for me to put the whole thing together...

Posts #181 and #189 are the complete circuit (capsule to XLR out). The two are connected by a 5-pin DIN mini-cable. I converted the bodies into 'compacts' with captive cabels to be as lightweight as possible when up on a tall stand, so only the FET circuit is in the mic bodies (with the out circuits in a seperate enclosure which also contains the batteries). The end caps of the mic bodies are 1/2" copper pipe caps. I'm sure the whole thing could use some addt'nl RF filtering, though it hasn't been an issue as of yet.

That type of FET circuit is called 'constant current source'; not often used in microphones except for some AKG models.

I don't have transformers anywhere in the signal path of any of my mics or preamps (only in my two AKG LDCs, which rarely get used).

 

[Emmathom]

@k brown I see a transformer in your second schem (the "PSU" part)

You said (post#178) : Shown is how I use it with the Primo EM23, but for the Oktava it's the same except for the required parts for the capsule polarization. For that I use a pack of 5 rechargeable 9v batteries and tap off the 27v for the B1 power. The LiPo batteries I use are 7.4v, so the totals are actually 22.2v and 37v... The output circuit on the right is adapted from the AT8533 power module (in a remote box) without it's FET biasing resistor, and using the supplied transformer just as a way to tap off the phantom power.

So no, it's not an OPT but you mention (and dranw) a transformer in your schem...

Please excuse me but it's not that clear... and a schem without voltages is a bit confusing... didn't you made a clean drawing of your project ? at least to have a clear view of the job to do ?

PS : the "little Oktava" seems to be a good mechanical work

Regards

 

[soliloqueen]

I think the biggest problem with it is that humans likely evolved to perceive sounds situated at the rear as a threat. Even when it “sounds good”, it can be subtly agitating.

sometimes you say the most interesting **** george. i really think you might be on to something here. there's an in built drive to turn around and look at the rear sound that cannot be satiated when it's a recording and must therefore constantly be suppressed. not sarcasm. this is a seriously interesting observation that i'm going to be thinking about for hours.

 

[ccaudle]

there's an in built drive to turn around and look at the rear sound

For discrete sound sources. Surround can be very nice when it provides a realistic diffuse rear ambience, which you don't get with front speakers in a domestic size room.

 

[k brown]

@k brown I see a transformer in your second schem (the "PSU" part)

You said (post#178) : Shown is how I use it with the Primo EM23, but for the Oktava it's the same except for the required parts for the capsule polarization. For that I use a pack of 5 rechargeable 9v batteries and tap off the 27v for the B1 power. The LiPo batteries I use are 7.4v, so the totals are actually 22.2v and 37v... The output circuit on the right is adapted from the AT8533 power module (in a remote box) without it's FET biasing resistor, and using the supplied transformer just as a way to tap off the phantom power.

So no, it's not an OPT but you mention (and dranw) a transformer in your schem...

Please excuse me but it's not that clear... and a schem without voltages is a bit confusing... didn't you made a clean drawing of your project ? at least to have a clear view of the job to do ?

PS : the "little Oktava" seems to be a good mechanical work

Regards

Nothing connected to that trafo's primary, so no audio passes through it; no advantage over a pair of resistors, it's just out of convenience because it's part of the Audio Technica ES945 power module that I used.

 

[k brown]

For discrete sound sources. Surround can be very nice when it provides a realistic diffuse rear ambience, which you don't get with front speakers in a domestic size room.

Even back in the days of Quad, hall ambience for Classical recordings was the best use of rear channels.

 

[ubxf]

I'm a big fan of dolby atmos, and if you have any recommendations for a good classical music recording in 7.1.4 I'd love to listen to it. So far I've only found electronic music taking full advantage of the atmos format.

 

[kags]

I'm a big fan of dolby atmos, and if you have any recommendations for a good classical music recording in 7.1.4 I'd love to listen to it. So far I've only found electronic music taking full advantage of the atmos format.

Here is a playlist I recently put together for an article I wrote for a speaker manufacturer’s website about immersive mixing. There are plenty more great titles and recently the quality of Atmos mixes has improved (for many reasons). I’ll post and others can add to it. Maybe this deserves its own thread. Sorry for the formatting, but it should be obvious which is the artist, song, album. All are available on Apple Music. It covers all genres.

Song Artist Album​

Jealousy Olivia Rodrigo Sour

This immersive mix is even better than the stereo version. Great vocal tone and excellent use of space for the synths and background vocals.

Where We Used to Live e.s.t. Tuesday Wonderland

The piano really fills the room while maintaining its natural tone. A great example of modern-sounding traditional jazz.

Calling Your Name Jon Batiste World Music Radio

Well-balanced pop mix with spacious reverbs and atmospheres.

Damage H.E.R. Back of My Mind

Excellent use of immersive space and room-filling low end.

Worm Ride Hans Zimmer Dune: Part Two (Orig. Soundtrack)

Epic film score that’s not shy of the overhead channels.


Cello Suite No. 1 in G Major: Prelude Yo-Yo Ma Bach: Unaccompanied Cello Suites

Rich tones from Yo Yo Ma and a room full of ambience.

Motorbike Leon Bridges Gold-Diggers Sound

Swirling guitars and center-focused groove and vocals.

Motley Crew Post Malone Single

This immersive mix blends surrounding ambience with powerful and clear low-end.

Shape of You Ed Sheeran + (Deluxe)

Forward-focused (though immersive) and polite until the surprise drop in the chorus.

Andante Andris Nelsons Bruckner Symphony in D (2023)

Wonderful orchestral textures in a lush-sounding hall.

Glassworks: I Opening Angele Dubeau (arr) La Pieta Promenade (Budapest Symph)

The intro violin emerges from behind the piano and the orchestra remains front and center as the room fills like small concert hall.

No. 3, Pour les quartes Steven Osborne 12 Etudes, CD143, Debussy

Excellent piano performance and recording with just a hint of natural immersive ambience.

Long Road Home Oneohtrix Pint Never Magic Oneogtrix Point Never (Expanded Edition)

Quirky Experimental electronic scoring with surprising immersive elements.

Basic Avenue Yello Point

Classic electronica expanded to fill the room with ambience, percussion, and swirling elements. Impressive bass drops, too.

Boom Tiesto and Sevenn Single

An immersive showpiece. This mix showcases transient response and the height speakers.

Parcels Once Day/Night

Alternative, retro, indie, immersive fun.

 

[ubxf]

Thank you , I guess starting a new thread on this subject might be good