Classical Recording Mixer

Hi all,

I've got a pair of modded MXL603s mics, modded MXL 990 (all cap upgrades -- boy the Styroflex's sound AWESOME), and 3 modded Rane MS1b preamps.
(G9 is not done yet unfortunately).

Now I need a simple mixer for my new low-cost Decca-Tree rig! I want to build something --maybe even tube (I love the RCA Living Stereo Recordings, they used 3 Neumann M50's into an Ampex 300-3 via a custom mixer.)

So, I need pans on all 3 channels, and I may as well make this a 4 channel box as I do have another preamp to use.

Found some cool stuff in the Meta, namely the "Domestic Recording" tube mixer. Looks intriguing but it appears to me that there's an MS matrix in there, and also it looks like this is also is a mic pre.? Am I reading that right?

So, anyway, I want to build a simple 3 or 4 channel high-quality mixer, 4 balanced line in, balanced stereo output. Any suggestions/schematics/theory?

Then I need to see if my mics will really work in this application. The M50s were omni but more directional as frequency went up. Also, I fear that the tube electronics had a lot to do with the liveliness and presence. Trying to keep things simple and low cost might make tubes a little tough for me without a schematic, etc.

Any takers?

:?:

Must admit I had the Decca-tree in mind when looking for an excuse to buy more of those MCA SP-1's :wink:
(but I didn't)

Hmm, so you're thinking of doing the Decca with card.-patterns ? Did some further 'research' on this ?

Regards,

Peter

Yes I've done some research! The original M50s became very directional at high frequencies. In listening to the 603S, you can hum a low frequency while moving around the mic with not "too much" change. I made a foam ball and added that to the mic. (looks like a round ENG mic flag) Positioned so that the curve starts right behind the vents around the capsule. Made a change, but I can't say that it was any more or less directional.

The 603s is advertised as a "wide cardiod". Maybe I should be starting with an omni and then adding the curved ball the way Neumann did with the M50.

The MXL 990 looks good for the job (case design) but its cardiod and uses the 603s capsule.

BUT, after I've listened to the 603s, I will say that the mic sounds omni-ish to me, so that's why I feel it might work out for my sub $500 Decca tree.

Definitely open to ideas!

Dunno what it is, but those 'lesser used*' mic-configurations have a certain appeal... like this Decca, and the Jecklin-disc. maybe there's a very good reason these aren't used more widely, but so far they
seem nice for toying around with.

I didn't do much 'research' myself, did you found that there a 'scientific' reason that Decca requires omni's ? OK, the wide card. of your mics sounds comparable then, or at least worth a try... but those MCA SP-1 are out then, these are more narrow.


[quote author="riggler"]I love the RCA Living Stereo Recordings,?[/quote]
If only already for that lovely 'banner' on the record-cover :wink:

Cheers,

Peter

*: at least for rock/pop-stuff

I didn't do much 'research' myself, did you found that there a 'scientific' reason that Decca requires omni's ? OK, the wide card. of your mics sounds comparable then, or at least worth a try... but those MCA SP-1 are out then, these are more narrow.

Click to expand...

Well, I'm waiting on a book that will come in on library loan to read about these recordings. As of right now, the assumption is that the omni pattern in the the low end gives width -- a big sound -- but the narrower high end gives articulation.

You may want a few more channels in your mixer than 4 depending on what types of recording you are doing. The traditional Decca setup for a full symphony recording was a minimum of five mikes, 3 in the "tree" and stage left and stage right outriggers, one third the distance from the proscenium. Small ensembles were recorded with just the three tree mikes. Here is a reference:

http://www.acmi.net.au/AIC/DECCA_TREE.html

Apparently, the original use was with cardioid mikes, with a wedge shaped baffle between them. The final form was with three omnis.

FWIW, stumbled upon a mini DIY Decca tree, even with different mics:

http://www.vsplanet.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=6;t=009672

http://img486.imageshack.us/slideshow/player.php?id=img486/716/118968369562g.smil

yikes!!!

That isn't a Decca tree, not by ANY stretch of even the most twisted imagination. -That's just three random mics thrown together and amateurishly recorded. By that definition, if I were to put three close mics on a lick, snare and hi-hat, I might start calling that a Decca Tree... sheesh!!!

THIS is a Decca tree.

At present I'm recording a solo violin CD and also a viola CD, in a local recital hall. Been at it for a few days, and taking a break to install some consoles.

The setup that worksi well in that room for solo stuff is a AKG C12VR tube mic at about 6 feet over the instrument, and a Soundfield for the room ambience, about five-eighths of the way back in the hall, about eighteen feet off the ground.

I have a set of 603's and I find it they work reasonably well for stereo pair, but not so much in a Decca tree arrangement: more of a near-coincident seems to work better, and I've taken to placing a small hypercardioid mic in the middle whenever I use them, so that I can call up a 'hard-center' if necessary. (also useful for L-C-R assignment when making 5.1 versions... -Ths Soundfield can MORE than handle the rest!) I suppose if anything, THAT is closer to a "mini-Decca tree" than the nonsense posted in the above link, but even then I'd NEVER use that term: It's a near-coincident pair with a hard center.

FWIW, I like to use the 603s in an XY or near-coincident arrangement for choral support, where I might wish for more diction clarity on choral sections, but I'm still an avid Soundfield user as the main microphone setup for ensemble recording.

To get back on topic: I'd work in the box, but I've stockpiled some P&G faders, some metalwork and was thinking of building an 8-channel mixer. -For the demands of classical, you'd want mic preamps beyond reproach, (think SSL 9k or green Pre) a bypassable high-pass filter, an available insert point, and a pan per channel, with hard de-assign switches to reduce the unnecessary gain in the summing amps. Maybe an FX send in case I needed "reverb support".

That's how I'd do it. Not too tricky, and one final thing:

Make.

It.

RELIABLE.



Keith

[quote author="SSLtech"]yikes!!!

That isn't a Decca tree, not by ANY stretch of even the most twisted imagination. -That's just three random mics thrown together and amateurishly recorded. By that definition, if I were to put three close mics on a lick, snare and hi-hat, I might start calling that a Decca Tree... sheesh!!![/quote]
Must admit I posted it and kept the further reading for later today, but yep, I guess of 'mini-Decca Tree 'the first word it the most & actually only applicable.

Apart from that, I'm wondering if a 'true tree' is mostly found for classical etc for a reason... as in: not used (at least I'm not aware of it) for rock-stuff: say a drumkit or for (overkill-)micing of for instance a gtr-setup.

Thanks for that link, that was the first encounter I had with a Decca setup a while ago, but couldn't find the file back.

Regards,

Peter

The Decca tree works because of the spacial seperation of the mikes. The center mike has predominance because the sound from the front arrives at it 5-6 msec earlier than the L & R mikes. The distance has to be carefully controlled and the distance is not small (~1.5 mtr spacing between the front and sides). I think the width could be related to the average spacing of the reproducing speakers.

The original experimenters were concerned with reproducing the aural ambience of the recording space into the suboptimal space of a listening room. Trying to get all the information about time of flight and reverberation of a complex environment pulled like two noodles through two reproducers and then reconstructed into a sonic panorama on the other side. Dolby and others studied these phenomena very carefully and understood the aural effects of shading, reverbaration and time delay on the reconstruction of the sonic space.

Not interested at all in using a Decca tree for rock. Got my bases covered for drum overheads, etc.

Okay, so I actually have in my hands "Living Stereo, The RCA Bible".

It documents the history of the mics and arrangements, use of outriggers, etc.

The reference recording for me personally is #1934, Bartok's Concerto for Orchestra, conducted by Fritz Reiner, performed by Chicago Symphony, engineered by Layton. Recorded in Chicago Symphony Hall in 1955.

According to this text, this recording could have been 3 Neumann M50's in Decca arrangement, or more probably a pair of M50s in spaced pair. (A chart illustrating this looks to be about 20' apart, 10' from the front of the orchestra.)

SO now I'm wondering if this recording I love so much is even Decca at all!

This text says that in 1956 Layton added a third mic.

SO...... anyone have a more authorative source?

If I can get away with a pair, then I need no mixer, and I think I'd do the Royer tube mod to my 603S's and finish the G9!!

-D

Its unlikely that this recording was made using a Decca tree arrangement. RCAs association with Decca began in 1957 when RCA switched its UK distribution from EMI to London/Decca.

Living Stereo recordings, released on vinyl became available in 1958. Prior to that, RCA released stereo recordings only on magnetic tape. So while this recording may have been released as "Living Stereo" the actual performance was taped prior to the Decca/RCA era.

Burdij,

Where are you finding this information? Just curious. I'd like to read up on it. Thanks!

[quote author="burdij"]The Decca tree works because of the spacial seperation of the mikes. The center mike has predominance because the sound from the front arrives at it 5-6 msec earlier than the L & R mikes. The distance has to be carefully controlled and the distance is not small (~1.5 mtr spacing between the front and sides).[/quote]
OK, Decca 'officialy' requiring three omni's, but I have only a pair. For lack of a third, I figure a cardioid could be used for the centre, but how about sort of merging Decca & XY ?

In other words: the centre omni is replaced by a card. pair in XY.
Obviously the 'two lefts' & 'two rights' should be properly routed, and then I can still imagine it can become a big mess..... but how about it for an idea ?

So all mics in the pic below are used, except for the MS. Overkill possibly, but 4 i.s.o. 3 is not much more work. The idea to use Decca to record a rock-band i.s.o. a bunch of well-dressed people might be actually more overkill :wink:



Bye,

Peter