Resonator guitar
Dobro
- Sources
- 65 independent: not from a mic maker
What it is
A guitar with one or more spun metal cones under the bridge instead of (or as well as) a soundboard. Square-neck "dobros" are played flat on the lap with a bar (bluegrass, country); round-neck "nationals" are held like a guitar (blues slide). Also called resophonic guitar. The lap steel proper is covered in its own entry.7,4
Also called dobro.
Range
from E2 (top not sourced)782.4 Hz
lowest open string in standard tuning; the top is not sourced
The sound
Strings drive the cone through the bridge. Wikipedia lists tricone, biscuit and spider-bridge (Dobro) designs. Messer calls it "more like a speaker cabinet" than a guitar; Heffernan says the main sound is the cone plus the ported sound of the screen holes, "basically bass ports".7,4
Where the sound goes
The cone sends sound up and out and also down into the body, where it leaves through the screen holes or f-holes; the cone gives the brash high-mids and the ports the warmth below. Recorded timbre changes completely with mic position over the cone, back of the cone, f-holes or ports.4
About the range
Square-neck bluegrass tunings are open G, written as GBDGBD or DGDGBD (low to high; octaves not given), or open D. Taking GBDGBD as G2 B2 D3 G3 B3 D4 (estimate). Round-neck: standard guitar tuning E2-A2-D3-G3-B3-E4 (the page says conventional tuning is popular).7
How loud
Sound pressure level measurements as published. Different kinds of figure (a playing level, a peak, a dose at the player's ear) can't be compared with each other, and neither can figures at different distances.
| Playing level | |
|---|---|
| 105 dB | close mic, on stage5 |
Shure's Cliff Miller measured Jerry Douglas's dobro, close-miked on stage, at 105 dB (weighting and distance not given). It was designed to be louder than ordinary acoustic guitars, and the Dobro design made more volume than National's tricone.5,7
Recording it
- Single mic: start between the cone and the f-holes, and not too close. Heffernan's own favourite is a KM 84 or KM 184 aimed between the cover plate and the port, "not at the centre of the coverplate and the hands". Mike Auldridge recorded with a KM 84 and moved it round the room until it sounded right.
- Two mics: Heffernan puts a small-diaphragm condenser close and a large condenser two feet away for a rounder picture. Messer prefers one mic, but for hi-fi suggests a ribbon at the back of the cone and a condenser toward the bass end.
- Large mics: Bil VornDick uses an XY pair of large condensers (AKG C12, Neumann U 67 or U 47) above the lap-held instrument; Heffernan also names Peluso P12, Neumann U 87, Lawson L47, Royer R-121 and Beyerdynamic M 160. John Wheeler says the U 87 does "excellent duty on dobro and banjo".
- Bartlett: a flat condenser 6-8 in from the sound hole. Randy Kohrs uses Royer ribbons (his video for Royer; no model named in the page).
- Keep the mic away from the picks: Messer says close miking "you tend to only get the sound of the picks", Heffernan never has a mic near them.
- Messer suggests an SM57 can be the better choice when string and slide noise is the problem; for character he has used a very old cheap AKG six feet away.4,2,3,1
Mics
- 15 setups from 6 sources, 5 of them independent of any mic maker.
- On top: the mics more than one source names for this instrument, in any role, the most named first. That is a count of sources, not our verdict.
- In the full list, each mic shows how many sources name it for that role, and how many of those come from a mic maker.
- Neumann U 87 (U 87 i) 2 sourcesClose
- Shure SM57 2 sourcesClose
All the mics sources name, by setting and role (16)
Studio
Close
- AKG C121 source
- Beyerdynamic M 1601 source
- Lawson L471 source
- Neumann KM 1841 source
- Neumann KM 841 source
- Neumann U 471 source
- Neumann U 671 source
- Neumann U 872 sources
- Peluso P121 source
- Royer R-1211 source
- sE Electronics Rupert Neve Signature condenser1 source
X-Y
The 10 setups behind this: placement and quotes
- Close Royer ribbon mics (model not named), Randy Kohrsclose
Randy Kohrs recorded a Royer Labs how-to video on mic placement for dobro, banjo, fiddle and drums (ribbon mics).
1 - Close Neumann U 87close, studio (distance not given)
The U87 is my main duty vocal and fiddle mic. It also does excellent duty on dobro and banjo.
2 - Close flat (boundary) condenser, 6-8 in from sound holeclose
Place a flat condenser mic about 6 to 8 inches away from an f-hole or sound hole (mandolin, bouzouki, resonator, lap dulcimer).
3 - Close Neumann KM 84close, between cone and port
My favourite mic is a Neumann KM84 or KM184. Mike Auldridge recorded everything with a KM84.
4 - Close Neumann KM 184close, between cover plate and port
I get an incredibly warm sound with the KM184, pointing between the cover plate and the port.
4 - Close Neumann U 87close/ambient, 2 ft
I'll also use large-diaphragm mics like the Peluso P12 or Neumann U87.
4 - Close Peluso P12 or Lawson L47 or Royer R-121 or Beyerdynamic M 160close/ambient
I'll also use large-diaphragm mics like the Peluso P12 or Neumann U87. ... I use a Lawson L47, a U47 clone, and that gives me great results also. ... Also to some extent ribbon mics, like the Royer R121 and the Beyer 160. They're all going to give you good results. ... Also to some extent ribbon mics, like the Royer R121 and the Beyer 160.
4 - Close 2 × AKG C12pair, XY above the lap-held instrument
Some Nashville producers, like Bil VornDick, favour a pair of large condensers such as the AKG C12, Neumann U67 or U47 in XY above the instrument.
4 - Close 2 × Neumann U 67 or Neumann U 47pair, XY above the instrument
Bil VornDick favours a pair of large-diaphragm condensers such as the AKG C12, Neumann U67 or U47, set up in an X-Y configuration.
4 - Close sE Electronics Rupert Neve Signature condensersingle mic, hi-fi
If I'm going hi-fi, I might well use an sE Rupert Neve condenser or something like that (Michael Messer).
4
On stage
Close
- Shure KSM321 source from its own maker
- Shure KSM44A1 source from its own maker
- Shure SM571 source
Contact
- Fishman Nashville Series undersaddle pickup + Jerry Douglas Aura pedal1 source
- Highlander resonator pickup1 source
The 4 setups behind this: placement and quotes
- Close Shure KSM32 or Shure KSM44Aclose, stage
When we use a mic on the dobro, we use the KSM32 or KSM44A.
5 - Contact Fishman Nashville Series undersaddle pickup + Jerry Douglas Aura pedalpickup, live (dobro)
Jimmy Heffernan: the pickup alone misses the cone, but combined with the Jerry Douglas Aura pedal it is out of the park.
4 - Contact Highlander resonator pickuppickup, live (National)
The best pickup for a National guitar is the Highlander, which sits in the biscuit under the bridge, but it can't hear the whole picture (Messer).
4 - Close Shure SM574-6 in above strings, 15th fret to soundholes, angled 45 degrees
SM-57 between the 15th fret and the three little soundholes, 4-6 in above the strings, angled toward me to avoid feedback (forum poster).
6
Studio and stage
Close
- Shure SM571 source
The 1 setup behind this: placement and quotes
- Close Shure SM57close, live or to tame string noise
Michael Messer: you're actually better off sometimes putting an SM57 on it; it naturally cuts some string noise. Uses one live on his National.
4
On stage
Messer plays his National live through an SM57, flat EQ, with low foldback, moving the guitar on the mic to change tone; he prefers this to a pickup, naming the Highlander under the bridge as the best pickup but not hearing "the whole picture". Shure's engineers use a KSM32 or KSM44A on a dobro, or the player runs direct through a Fishman pedal. For dobro, small-diaphragm condensers on stage in a quiet bluegrass setting; with a loud band a clip-on or pickup; Heffernan likes a Fishman Nashville undersaddle pickup with the Jerry Douglas Aura pedal, since the pickup alone "totally misses the sound of the resonator cone". A forum poster uses an SM57 4-6 in above the strings between the 15th fret and the soundholes, angled about 45 degrees to the player to avoid feedback.4,5,6
Problems to watch
Pick, slide and string noise (metal on metal, amplified by the cone); feedback on stage, since the body is a resonant box; over-compression (treat it like a vocal; leave headroom).4
Sources
- Bluegrass Today: Mic placement tips from Randy Kohrs (Royer Labs video)
- Neumann: John Wheeler and the TLM 103 (engineer testimonial, Renaissance Recording Nashville)
- ProSoundWeb: A Guide to Microphone Techniques for Studio Recording, page 5
- Sound On Sound: Recording Resonator Guitars (David Greeves, 2016)
- Shure: How to Mic a Bluegrass Band (Les Banks, Cliff Miller interview)
- The Steel Guitar Forum: microphone position over dobro (stage) (thread)
- Wikipedia, Resonator guitar