Dave and I (Stan) are both engineers by day and jazz guitarists by night–gigging most weekends usually with different groups but occasionally as a jazz guitar duo. We have been frustrated searching for amps/speaker cabinets suitable for use with our archtop guitars, e.g., Gibson L-5, Heritage Sweet 16. We have bought one of just about everything that is out there looking for a speaker cabinet isn’t too boomy when the mid range is made fat and isn’t prone to feedback at moderate volumes. Use of parametric EQ and notch filters to control feedback are a hassle and detract from a balanced tone. We refused to accept that the problem was solely with our high end guitars.

Redstone Audio was formed in 2006 by Dave McElroy, Stan Lee and Gwen Jones. Dave is a retired electrical engineer (30 years at Texas Instruments); Stan is an Program Manager with the Army Corps of Engineers in Huntsville, Gwen Jones and his son, Lee are the best cabinet makers in this area (maybe the world!). More about Gwen: He holds a Ph.D. in Nuclear Physics and three Master of Science degrees. He left NASA after the Apollo program was over and turned a hobby (wood-working) into a booming business. Dave and Stan are both jazz guitar players, and, while Gwen doesn’t play an instrument, he once had a Hi Fi Speaker business supplying ADS. Gwen knows the ins and outs of manufacturing speaker cabinets.

After about a year of modeling, building and testing prototypes, we got it! Our reasonably small and lightweight cabinets allow an archtop guitarist to play louder with less feedback potential using a fat mid range tone and without excessive boominess in the bass. The choice of amplifier is no longer all important to tone. With Redstone speaker cabs, the EQ on most amp heads can set be set flat or tweaked a little for desired effect. Dave even got me, a long time (30+ years) tube amplifier purest, to admit that solid state amps sound just as good as tube amps, but only with Redstone Audio speaker cabs, mind you.
 
Power handling capability? Both the 8" and 10" can handle 200 watts each. They sound best being driven by 50 watt or higher solid state or 30 watt or higher tube, for the reason that they are slightly less efficient than typical open back speakers. However, if your archtop guitar’s volume level is limited by the onset of feedback, Redstone Audio speaker cabs will provide you more volume headroom, in addition to a better overall jazz tone. Open back cabinets are uncontrollable and thus unsuitable in our opinion for archtop guitars, especially those with spruce tops.
 
How do Redstone Audio speaker cabs reduce feedback and boominess? Feedback with archtop guitars most often occurs along a range of notes from about Bb(116hz) on the 6th string up to open string G (196Hz),or the unison equivalent on other strings. The ideal speaker driver-cabinet volume combination for archtop guitar must produce a loudness versus frequency (pitch) curve that is flat (+/- 1 dB) along the feedback prone frequencies. The curve should start angling downward for notes lower than 5th string C on the guitar to avoid boominess. Attenuation (lessening) of the loudness of lower notes by the speaker-cabinet system not only brings the low strings into balance with the loudness of the higher notes on the guitar, but the first and second order overtones (octave and fifth above) produced by the low notes will become more audible. What sound quality does that produce? Some people describe it as “woody sounding”. Remember that the design intent for acoustic archtop guitars is to amplify the midrange notes at the expense of the bass. Design works well acoustically but pickups and amplifiers work against that design intent, hence the need for speaker cabinets that are tuned specifically for archtop guitars.