DIY Purist Recording On A Budget

This info resulted from my co-producing a “live vs. recorded” exhibit at January 2010 T.H.E. Show in Las Vegas, recording the pre/post seasoning primeVibe audio clips posted at our website, professional recording experience, home recording, and recording in a large commercial space with ideal acoustic qualities.  The three primary criteria are:

  1. Simplicity
  2. Lowest possible cost
  3. Convey acoustic music with pure, accurate, and transparent recordings and no post editing

At the show mentioned above, a friend audio-recorded professional finger style guitarist Austin Weyand in a hotel ballroom playing three fine Ryan Thorell guitars (one arch top, two flattops).  The sum total audio hardware comprised a mic stand, OEM mic cable, and:

  1. Audio Technica AT825 stereo condenser microphone (discontinued, last MSRP $550 USD) plugged directly into the L/R balanced mic inputs of a…
  2. Korg MR1000 DSD 1-bit 5.6 MHz (twice SACD rate) portable stereo recorder, about $1250 USD

After hearing the resulting recordings and reading about the technology in the Korg, I was convinced it is one of the highest performance stereo audio recording devices in production.  I love tubes, vinyl, and analog.  I’ve listened to superb half-track 10-1/2″ reel professional analog tape decks including Studer, Ampex, and a John Curl-modified deck.

The Korg can play back its own DSD music files.  Audiophiles should know that users may also author DSD discs and play them on a Sony Playstation. Even “lowly” CD files mastered from the Korg’s DSD files are a razor close replica of the original event.  I hired guitarist Austin Weyand several times and played with him.  I sell Thorell guitars, the brand he plays.  The recording accurately portrays Austin’s fine guitar and his nuanced playing.  It replicates the original acoustic space.  About twenty attendees sat in the audience including myself.  I can sense my location in the audience, the people surrounding me, even distant chatter out the door in the hallway.  I even picture the lighting in the recording venue.  It’s amazing.

Two professional balanced microphones (or one stereo) are mandatory to meet the desired performance goal.  We purchased an AT825 stereo mic (used $140) as described above for its proven performance and its simplicity in use (dual-elements in 110-degree X-Y angle).  The OEM mic cable was missing so I made a high quality stereo balanced cable w/ Canare Star Quad snake wire for two mics, about $1.80/ft:  Also required are one 5XLRF for the mic end and two 3XLRM for the load end of the cable (suggest Neutrik, available from the same source as the cable above).

We’d like to get the Korg MR1000.  Meanwhile, two self-contained portable stereo audio recording devices appear worth recommending (no outboard mic interface required).  One is the $100 Zoom H1 or $180 Zoom H2, each with external mic input.  We purchased the Canon ZR-960 Mini DV camcorder, direct from Canon, $200 while supplies last (“refurbished,” meaning new w/ 90-day warranty vs. one year).  Beyond great video quality the ZR-960 records audio in uncompressed 16 bit 48 kHz, same as CD quality.  Uploading Mini DV requires firewire; I paid only $6 for firewire cards for my desktop computer.

The problem arises of connecting the pro microphone’s balanced XLR cable to the unbalanced 3.5mm phone jack of consumer gear, requiring either an active preamp or matching transformer.  (The Korg being a pro piece sports L/R balanced XLR jacks.  The fact that only a mic is required contributes much to its performance.  One cannot overstate the performance advantage of improvements in the recording chain, the weakest link in most audio systems.  This explains the outboard mic requirement.  New pro mics go up to the $5k range while choice rare discontinued mics may have higher value (like choice vintage instruments).  Now estimate the value of the mics in a $180 MSRP self-contained recording device such as the Zoom H2 and you get the picture.)

Pro audio company Rane compiled the latest A.E.S.-recommended cable wiring techniques and balanced to unbalanced conversion here: I decided against the $180 Beechtek transformer because of cost and potential performance degradation arising from unnecessary switching and level control.  Music/pro audio sources sell impedance matching transformers w/ XLR input and ¼” phone plug output, $15-$20 each.  I purchased two such adapters.  To increase resolution I soldered a 3.5mm TRS plug to one end of Canare Star Quad wire, and hard-soldered the other end directly to the impedance matching transformer’s ¼” phone plug (tape and/or heat shrink the exposed conductors; confirm L/R orientation of the TRS plug).

A top-level high-end audio engineer recommends UTC A-20 ultra-high resolution impedance matching transformers; I plan to upgrade to these later.  The last pair at eBay sold for $140.  See the Rane document for wiring diagram.  One UTC owner estimates they are 10-12 oz. ea.  Two UTC transformers in a box with XLR input and hard-wired output may be very heavy.  The only known method to accommodate the weight with a hand-held camcorder is to attach the box to the user’s waist with the shortest possible output cord to the camcorder.  For a stationary camcorder on a tripod you may be able to fasten the heavy transformer box to the tripod.

Make brief test recordings while testing various mic heights, spacing, and vertical angle.  4′ mic spacing is preferred in our 25.5 x 16.5 x 7.5′ sound room. Decreased spacing increases image size and ratio of direct sound to ambiance effects, while increased spacing has the opposite effects. The instrument’s real acoustic image size should ideally match that of the recording, but this effect must be balanced against the ratio of direct sound to ambiance effects.  The mic’s vertical angle affects tonal balance: high frequency energy is maximized on axis, decreased by angling it upward.  We’ll report on the effect of mic height shortly.

Natural room acoustic beats synthetic post-editing and provides realism and immediacy available no other way.  Our notes about “soundfield” and “sound intensity” may be helpful here Our thanks to John Marks of Stereophile for mentioning the Charter Oak Acoustics SP-1 headphones…we love the European version MB Quart 450/German Acoustics.  My Canon camcorder has no headphone output.  I made an adapter to connect the headphones to the AV output jack (3.5mm TRRS, not the ubiquitous TRS).  The level is fixed but it beats the built-in speaker.

Our intent is to help you make recordings of voice and acoustic instrument that you will cherish.  For not too much money you can make recordings that sound more natural and realistic than most commercial recordings.  Certainly the dynamic shadings can be exquisite compared to commercial recordings, many having the life squashed out of them via compression and limiting (making a whisper sound like a shout).  Synthetic post-recording ambiance sounds unpleasant and unattractive compared to acoustic, especially that supplied by a larger room.

We’ll post new uncompressed CD resolution recordings shortly.

Rough price tallies:

  1. Mic $150
  2. Mic boom $30
  3. Upgraded cable, connectors, low cost transformers $100
  4. Ultra high resolution transformers, chassis, 2 XLR jacks $200
  5. Recording devices: likely state of the art $1250, reasonable alternate $100, if you act soon excellent camcorder with CD quality audio $200

So, lower cost route about $400 total, or about $1500 for something unbeatable + alternate mics.   Transformers redundant with the Korg.  Not so bad, eh?

Have fun!

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