To Order call 678-269-6397

or email at

Price: $1599.00
Plus shipping

The DriveBox

for 5-String Banjo

Price: $1899.00
Plus shipping

Engineered specifically for the 5-String Banjo, the DriveBox has an accurate dynamic range which reproduces the unique, complex tones and voicing of this special instrument. When paired with high quality piezo pickups or microphones the DriveBox gives a powerful sound experience with depth and presence while faithfully reproducing the tones and voices of your natural instrument. Your amplified sound will be the closest to your natural instrument possible and you’ll be amazed at how big you sound without any unwanted coloration of your tone.


Power: 250W
Speaker Driver(s): (2) 12” Eminence Drivers @ 8 Ω each.

                                    Total Cabinet Input Impedance = 4 Ω
Dimensions: 17”Wx 29”Hx 11.5”D
Weight: 30 lbs
Frequency Range: 80 Hz - 5 kHz
Signal Input: (1) Neutrik SpeakOn Connectors

To Order call 678-269-6397

or email at

Designed By Musicians – For Musicians

 As acoustic musicians we try to find ourselves the very finest instruments made by highly skilled artisans out of the finest woods. We search for the strings that give us exactly the response and tone we want for our specific playing styles and we spend money and time on every detail of our instrument until we have THE sound we want for our performances. Then we need to somehow amplify our sound for our larger audiences or just to get the room levels we need for the presence our music should have and all of a sudden what comes out of the PA no longer sounds like our beautiful instruments.

 Not anymore - Portmann Acoustics proudly present external speaker cabinets engineered and designed for SPECIFIC acoustic instruments to bring your amplified sound as close to your natural instrument as possible!

 Individually hand-crafted with fine attention to detail, these speaker cabinets are as much beautiful art to the eye as they are highly calibrated resonant acoustic cavities tuned to match the natural audio response of your fine acoustic instrument.

The results; a striking bohemian appearance with the rich texture and tones of dark tooled leather and polished wood, accented with inlaid carvings and a heavy black powder coated metal grill for a slight ‘retro’ touch. This gives the cabinet its own artistic character and presence which will draw every eye to the stage as it faithfully produces the clear and accurate tones of your own instrument.

Our speaker cabinets are made of high quality hardwood plywood with durable, reinforced vinyl coverings resembling real tooled leather, heavy duty cast-metal Neutrik Speak-On connectors, and rugged molded nylon corners. Portman Acoustics speaker cabinets currently come in two models; one for 5-string Banjo and one for 4-string Upright Bass with additional models for other acoustic instruments planned for future release as well as a line of specialty electronics and recommendations to assist you in every way to achieve the most excellent sound as close to your natural instrument as is possible.

The LowBox

for 4-String Upright Bass

The LowBox has been carefully engineered specifically for the 4-String Upright Acoustic Bass to accurately bring out those beautiful complex woody tones you find especially in carved-top or fully carved-basses. A rare earth 15” driver provides powerful low notes while having an extended high range to bring out those melodic high notes and thumb positions with equal clarity and presence. You will be amazed at the presence and volume while preserving the true natural tone of your bass without making it sound ‘electric’.


Power: 450W
Speaker Driver(s): (1) 15” Eminence Driver

                               Total Cabinet Input Impedance = 8 Ω
Dimensions: 25”Wx 30”Hx 18”D
Weight: 60 lbs
Frequency Range: 40 Hz - 3 kHz
Signal Input: (2) Neutrik Connectors

Progressive World,, Folk,

​Blues, and more

Virtuoso Music with Heart  & Soul


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