© Groove Tubes LLC. All Rights Reserved.

Groove Tubes

VELO-8Velocity (Ribbon) Microphone
Reference ManualFor the latest information on yourGroove Tubes product, visit our web site atwww.groovetubes.com
Or call us toll-free at(800) 459-5687

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VELO-8 REFERENCE MANUAL

A little background on “Velocity” mics
The VELO-8 name stands for “velocity” microphone, with a traditional“figure 8” polar pattern; hence, VELO-8. “Velocity microphone” is theoriginal name used by RCA, Electro-Voice and others for what we commonly
today call “ribbon” mics. They actually worked on reacting to sound wave
velocity (or audio wind), so the name fits if you understand the technology.
Most ribbon mics have a very thin aluminum element that looks like a silver
ribbon. It is moved (activated) by very small amounts of sound (or air velocity)from instruments or voice. This ultra-thin strip of metal is a double-edged
sword.
First the positive: its ultra-thin element can capture details with a smoothness
not found in any other microphone technology. It can make a saxophone soundsweet, not harsh. Ribbon mics can do the same for voice and many other
instruments that might record too bright or harsh using modern condenser mics.
Now the downside: while its thinness affords highly detailed sensitivity tosound waves, it is also easily damaged or torn if the accompanying air waves
are too strong. Higher air pressure levels, like those generated by a closely
miked strong vocalist or a bass drum on axis, can easily rip the thin aluminum
ribbon element resulting in a costly and time consuming re-ribboning repair
adventure. Replacing the torn ribbon is a delicate maneuver, and only possible
if performed by a highly experienced mic tech or a factory repair department.
Unfortunately, both in the early days and today, a broken ribbon element isquite common. If you find a good mic tech who can repair your ribbon
element, it can take weeks or months before you’re back in business. The old
RCA and Capital studios usually employed a full time tech whose only job was
to maintain their array of ribbon mics so studio time was not lost. But those
old ribbon tech guys are mostly gone today, and few younger techs have thetraining and/or experience to do a good ribbon repair. So today, we usually
have to search for that rare “ribbon mic guru” and send it to him, or in the caseof a newly produced ribbon mic, it would have to go back to the factory... andyou wait!
This is one reason velocity mics fell out of favor with most the larger studios,
who embraced the more modern and highly detailed condenser mics which are
not as easily damaged from higher levels of wind or air velocity common torock recordings.

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Another factor of the ribbon mics’fall from favor with modern studios was thatthey had very low signal output as compared to the electronically activatedhigher output condenser mics. They therefore required more preamplification
to get similar output levels, which add noise floor to the signal from theincreased amplification factor. For an example, listen to the hiss on Elvis’s“Love Me Tender” or Patty Cline’s “Crazy”, both recorded with early ribbon
mics.
In fact, ribbon mics can be up to 20dB weaker than condenser mics. This isreally a problem today, as most mixers and preamps do not have the low input
impedance to match the relatively low output impedance of the typical ribbon
mic (which uses a transformer to boost the impedance from 1 Ohm to maybe
100-200 Ohms). Also, the ribbon element’s output signal levels are too low as
well. Therefore, the “loading” is usually too high, and the preamp too weak toeffectively boost the level to the strength of the more common condenser mic.
Our ViPRE and SuPRE mic preamps were specifically designed to load the
ribbon with a matching balanced transformer winding of 300 Ohms, instead of
the industry standard of 2,000 Ohms or higher. These preamps also amplify
over 70dB, so this feature set was specifically intended to allow ViPRE and
SuPRE to address the special needs of preamplifying a ribbon mic, andduplicate the loading and amplification designs of the old RCA consoles whenvelocity mics populated the studios in the USA.

How the velocity mic works
Ribbon mics, both then and now, all work on the same basic principle; a thin
conductor (usually a strip of aluminum) is suspended and “tensioned” between
a magnetic field and is activated by sound waves, and this generates a small
signal voltage. This is similar to the way the more common dynamic mic
works, which uses its diaphragm suspended in a round magnetic field togenerate a signal voltage from its movement activated by sound waves, like asmall speaker in reverse.

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VELO-8 REFERENCE MANUALSo why do ribbon mics sound so different? These obvious sonic differences
result from variations in the few simple mic components; the ribbon, themagnetics, the transformer, and the interfacing design of these elements. The
craft and design to combine these three components is most important, as withany transducer… little things can make BIG differences! Let’s look at each ofthese four areas in detail, and discuss how we created VELO-8 to be the best
ribbon mic possible.
1. The Ribbon element: RCAmics had ribbons ranging in size from 2” longby 1/4” wide, down to about a quarter of that size. The thickness of thealuminum ribbon could vary from as thin as 2 microns to as thick as 8 microns.
As most of the old ones have been rebuilt (usually with thinnest material
available), few can be found with their original RCA-produced elements intact,and have usually been rebuilt many times using whatever thin aluminum they
could find. Also, the thin aluminum was hard to come by when RCA got outof the ribbon mic business in the late ‘50s. One common trick of the old studiotechs was to use the aluminum peeled off a gum wrapper, which is about 3
microns. Hand tensioning of the ribbon, or stretching it across the magnetic
field, was critical and rarely measured in any meaningful way… the old guys
just had a feel for it (or not!). Of course, the way the ribbon is crimped (or not
crimped) also contributes to the end audio result as well. This is why so few
vintage RCA mics today, even of the same models and era, sound exactly alike.
But some common truths are found; the larger the ribbon element the more
output level it generated (i.e., the RCA 44), and the thinness contributed tomore (or less) detail as well as more (or less) reliability. For example, a thicker
ribbon meant more durablity but gave less detail.
We like the old classic velocity mics VERY much, but didn’t want to just“reissue” an Elvis impersonator mic, as many have done. However, we did takea page from RCA velocity mics of the ‘50s, and a few tricks from Bang &Olufsen (B&O) ribbon mics of the ‘60s, and made ours a unique offering
which stresses the advantages of the ribbon mic, but also addresses theshortcomings. For example, our ribbon element is big and thin; VELO-8’s
aluminum ribbon is over 2 inches long, 1/10” wide, and is just 2.5 micron thick(human hair is about 10 microns, so it’s a quarter of the thickness of a strandof hair!). The ribbon element itself is also uniquely shaped; it is very precisely“dual formatted” to have two shapes, and both contribute to detail andreliability. VELO-8’s ribbon has both a curved area (in center) and a crimped
suspension area at either end of the ribbon to help it hold its precise tensioning.
This allows for maximum signal output and good long term stability. It is alsoprecisely tensioned by a special proprietary GT computer controlled system;
we call this “ribbon tuning”, so they all sound exactly the same (a must for

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stereo recordings!).
Lastly, our VELO-8’s ribbon is field interchangeable by the user (more on thatgroundbreaking feature later).
2. The Magnetics: The classic RCA 44 ribbon mics were relatively high signal
output devices (as compared with other ribbon mics) which was the result of alarger element and massive ceramic or Alnico alloy magnets placed around the
ribbon element; more magnetic field gives more output, just like guitar
pickups or speakers. These RCA 44 mics are favorites of engineers bothtoday and then... and captured early Elvis and Sinatra tracks quite nicely. These
early Capitol tracks were smoother than the later tracks by these same artists,
as they were mostly recorded with more highly-detailed and brighter condenser
mics like the Neumann U47. You will also notice more noise floor on the earlier recordings, but who cares? The “feel” of these performances could not havebeen captured any other way, and the truth is that both were great recordings,
but for different reasons!
However, today we have a new magnetic material, Neodymium, that is 100
times more powerful than the best of the old Alnico magnetic alloys that RCA
and others used. Also, unlike natural occurring magnets, the new materials canbe cast into special shapes. All previous ribbon mic magnetics, both yesterday
and today, have been made from off shelf square bars placed in a metal
conductor. But instead of using commonly available off shelf magnets, we
designed and custom cast a totally new “roof top” shaped magnet thatconcentrates the magnetic field on the edge of the ribbon and increases signal
output. We also used the highest quality aerospace Neodymium material thatcosts 20 times more than the common Neodymium magnets you’d find on yourmoney clips and refrigerator decorations. Furthermore, we choose to use a“high output roof top” magnet on BOTH sides of the ribbon. Most ribbons
today (and then) have just a single sided magnet that uses a steel chassis topass the magnetics to the opposite side of the ribbon element. This was themost costly approach... but of course, as we are suckers for quality andperformance, we believe it was well worth it, as this approach boosts bothsignal output (while lowering the floor noise) and improves detail (with more
depth and frequency response). In short, it simply makes for better recordings.
3. The Transformer: The transformer’s job is VERY important as it interfaces
the ribbon output to the preamplifier’s input. The ribbon element is typicallyvery low impedance, just one or two Ohms, and also needs a significant levelboost as well. Therefore, the transformer must boost both the output level andraise the impedance of the ribbon element, with as little degradation as possible

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VELO-8 REFERENCE MANUALto the signal. It can contribute much to the signal character, or it can degrade it
as well. Cheaply made transformers degrade the signal a bunch, but goodtransformers are costly. This is the main reason studio product designers have
moved away from using transformers in general and moved toward the MUCH
cheaper “active” differential input stages made with FET or, worse, op amps
for both output sections of microphones and input stages of preamps or mixers.
However, in the golden years of recording, there were excellent qualitytransformers placed in both the output stages of all ribbon mics, as well as the
input stages of the mixers... life was good, and nicely balanced too!
Today, however, due the the high cost of quality transformers and the very low
cost of solid state devices to make active input and output circuitry (and withproduct catalogs spinning this as some kind of positive verbage like“transformer-less inputs!”), high quality transformers at either end that can do
the math BUT not degrade the signal are a rare luxury. But luxurious sounding
they are! Adding a high-quality transformer to your mic or SSL console cancost you hundreds of dollars each, yet still many engineers swear bytransformers over cheaper and common active input stages. But they also
have the added advantage of total electrical isolation, which is not possible
with active circuitry. Certainly a cheap transformer can add unpleasantdistortion and frequency loss and/or shift, so we don’t recommend that. But
it’s interesting that many customers of lower cost Chinese ribbon mics are now
retrofitting them a higher quality Western-made output transformer made inEurope or here in the States that easily cost twice what they spent on the mic!
There is a noticeable improvement of course, as less degrading of the signal
path occurs. While it’s safe to say that the lower cost Chinese components ingeneral just do not measure up to the Western-made product, it’s also a fact
today that any highly labor intensive hand assembled product MUST be madeoffshore if the target is to keep the price within reach of the common man’s
studio. That’s why we make mics in the same GT captive mic factory where wehave made our condenser mics for nearly 15 years, and use the similar formulaof importing the higher quality Western-made critical signal path elements like
capsule elements, tubes and transformers.
So the “GT Rule” with transformers is to go big and stay home! We went big,
and we looked no further than the 118 freeway to find our favorite
microphone transformer builder, Cinemag. This company has been a GT
partner/vendor for many years. Cinemag designed and produces our custom
multi-stage variable input transformer at the heart of the ViPRE mic preamp,
which sounds incredible! The Cinemag company is co-owned and operated by
Tom Reichenbach in Chatsworth, California. Making transformers is a lost art
today, but it’s a family tradition for the Reichenbachs; Tom learned fromGROOVE TUBES

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perhaps the very best “wire winder” ever, his dad Ed Reichenbach. Ed owned
and operated Reichenbach Transformer company during the golden age of Los
Angeles studios. He made transformers for all applications, including for thestudios. One of his outside sales guys was Dean Jensen. Dean specialized instudio customers and audio manufactures and helped design transformers to fit
their demanding needs. Dean was a sales engineer, Ed was the designer andmanufacturer. Later, Jensen formed his own sales company and named these“Jensen” transformers gaining (at that time) a high reputation for making
perhaps the best sounding transformers of the day. But Dean’s offices werealways located inside Ed’s transformer factory and Ed actually made theseclassic Jensen transformers! Unfortunately, when Dean died, his business went
into a bankruptcy proceeding which resulted in the Jensen brand name being
sold to a former employee, and Ed simply retired and sold the Richenbach
factory. Soon after that, Tom started his own transformer business under the
direction of his dad. Frankly spoken, we’ve sampled all the best transformers
at every price point made today, and Tom’s transformers out perform them all
every time... so we stayed with Tom on the VELO-8 project and it really paid
off. Here’s what Tom and GT came up with in this latest collaboration.
The VELO-8 transformer uses pure nickel core laminates with multi-tapped
output windings that allow the level to be switched between 75 Ohms (mostdetail) and 300 Ohms (most signal strength). We also added a High Pass filter
for both windings so there are four switched selections located on the lower
rear side of VELO-8’s body. The highest signal level is achieved in the 300
Ohm position. The 75 Ohm position will have less output but also will beobviously “altered” and so will provide more natural detailed results, but it will
require more preamplification that may not be available on some mixers (butperfect for ViPRE and SuPRE either way!). Also, the low frequency roll off canbe useful as ribbons really produce a lot of information in this the ultra low
bandwidth area which could make a voice, drum or guitar sound too boomy.
4. The Design: Actually the size and shape of the ribbon, placement of theribbon in the magnetic field, and quality of the coupling transformer which
boosts the impedance of the ribbon’s output are the most influential
components to the end result, but without a coherent design to combine them
all could be lost! Our VELO-8 design is an original (not another “Elvis
impersonator”, please!); it has higher than normal output levels as a result of
the increased magnetic field created by our custom formed dual “roof top”
magnets and special designed Cinemag transformer. It offers a dual contrasting
ribbon placement design that produces different, but desirable, sounds fromboth the front and rear of the mic. Now, the engineer has two different
sounding sides to choose from; the back side is less bright than the front side.

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VELO-8 REFERENCE MANUALThe dual contrasting sides, combined with our four selectable impedance androll off options, give you eight different ways to use VELO-8! By the way, we
think you will use all eight for various applications... and that was the idea,
options are a good thing!
4a. VELO-8’s Field Replaceable Ribbon! This is perhaps the most
revolutionary part of our design: our exclusive field interchangeable ribbon
assembly. We anticipated that many of our customers will have never owned
or operated a ribbon mic before (mostly because more folks can actually afford
our VELO-8 as opposed to other ribbons). We also know that they willprobably NOT read our several cautionary statements about ribbon preservation(i.e., STRONG AIR DIRECTLY ON THE RIBBON WILL CAUSEDAMAGE! ALWAYS USE A POP FILTER WHEN CLOSE MIKING!).
So when and if the ribbon gets blown out with your girlfriend’s best attempt at
a Janis Joplin cover song, you can be back in business in about 10 minutes,
and not 10 weeks! How is that possible, you may ask? Because our VELO-8
ribbon is mounted and precisely pre-tensioned on a unique circuit board
material so it can be replaced in minutes; the process involves removing justfour screws on the chassis, and another four screws on the motor with a simple
procedure that takes about 10 minutes, start to finish!
“So How To?”: Notice when you unpack your VELO-8, there will be a small
pre-tensioned ribbon assembly mounted on a small PCB and sealed in ananti-static package in your VELO-8 carrying case. By the way, the design of
the VELO-8 vertical storage case has an important purpose: keeping VELO-8
upright in storage will avoid “ribbon sag” which can occur over time anddegrade the performance if stored horizontally. The following chapter of thismanual will show you, step-by-step, how to quickly replace your VELO-8
ribbon assembly should it be necessary. So, if this should ever happen to you,you can take comfort in two realities: first, you can whip out your spare ribbon
and replace it in 10 minutes (NOTE: the extra ribbon sub-assembly is includedin the VELO-8 package!), and secondly, you can send us back your broken ribbon sub-assembly in its special plastic package and we’ll return it to you for areasonable service charge!

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Replacing your VELO-8 PCB ribbon assembly
1. Getting Started
Begin with a flat, clean, non-metallic
work surface... a wood table is perfect.
Make sure to remove all metal items thatmight be attracted to the VELO-8’s very
powerful magnets. You will need a
VELO-8 replacement ribbon (obviously),a small #1 Phillips screwdriver, a pairsmall scissors to open your anti-static
non-hermetically sealed ribbon assemblypouch (we like these small Swiss army knives, but this is not really necessary,any pair will do) and a pair of soft, clean hands (do what your Mother says;
wash your hands!)
2. Disassembly
2a. Using the #1 Phillips screw driver, carefully remove the two chassis mounting
screws located on the bottom of the VELO-8
on either side of the XLR connector.
CAUTION: Be sure to keep all screws agood distance from the open mic chassis as
VELO-8’s magnets are extremely powerfuland so can attract metal objects in close
proximity, and at a great velocity, possibly
damaging the ribbon element.
2b. Carefully slide off the bottom portion of
the chassis/shell (downward), taking care not
to damage the impedance and roll-off switch.
2c. Carefully remove the (2) #1 Phillips
screws located directly underneath the platform housing plate which divides the internal chassis. These two screws attach
the platform assembly to the top head shell/screen.
2d. Carefully (did we say “carefully”
enough yet?) slide off the top head/shell(upward), being very careful not to touch
the motor assembly. Note that the threaded
inside part of the mic head is magnetic andcan stick to the ribbon motor... so keep it
centered as you lift it off... you can do it!
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VELO-8 REFERENCE MANUAL

2e. Disconnect the cable lead connector from the motor assembly to
the PCB near the impedance
switch, and carefully (there’s thatword yet again) slide the connector
harness through the round opening(should we be so common as tojust say “small hole”) locatedbetween the upper and lower portions of the VELO-8 motor mounting platform. Move this assembly away from the motor.
2f. With one hand, hold the sides of the motor assembly and PCB keeping slight pressure on the PCB toensure its alignment when the screws are removed.
This sounds hard, but it’s not, and you will feel soaccomplished when this is finally over.

2g. Remove the top screws first and movethese away from the work area. Keepconsistent pressure on the PCB andremove the bottom screws.
2h. Slowly (and shall we say, carefully?)
lift the PCB up and away from the motor
assembly. Now you are ready to change
out with the new PCB ribbon assembly
2i. Use your scissors (bet you thought
we forgot about the scissors, eh?) to
cut the anti-static pouch at one end.
Try to preserve the old bag to repack
your PCB assembly for reshipment
back to us. Now set your new ribbon
on the table, and get ready to
re-ribbon!

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3.0 Reassembly:
Basically, these reassembly steps are in reverse order, so many of you will findthese truths to be self evident, but in case you like the full hand-holding
instruction session, here goes:
3a. Carefully (maybe I should try“cautiously” just one time, what
do you think? ) place the bottomof the PCB at the base of the
motor and hold with one hand,
this means the PCB ribbon
assembly will be at an angle so as
to slide evenly into the gap
between the magnets.
Now slowly lower the PCB into the area between the two magnetic polepieces, making sure at all times that the ribbon does not touch anything in theprocess. Remember this is gum wrapper thin aluminum, one-quarter the thickness of hair and VERY fragile... so any strong breath, or touching it against
anything could rip it to shreds (well, maybe not shreds, but it wouldn’t be ahappy moment if you inadvertently broke it at this delicate and latestage in the game).
3b. Hold the PCB against the
motor chassis with one hand,ensuring that the holes on the
PCB are lined up with the holeson the motor assembly, and carefully (are you getting tired of thisword yet? I know I am!) insert
one screw at a time. Then, using a #1 Phillips screw driver, just snug up all
four screws but do not overtighten them until all four are in place and “snug”
tight.
3c. Gently tighten the screws in an “X” pattern. They do not have to be torqued
with a wrench, they just need to be tightened equally to keep the ribbon as centered as possible. Overtightening the first screw can tend to offset the ribbon
and so we recommend this alternating “X” system like you’d use on a drum
head.

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VELO-8 REFERENCE MANUAL

3d. Use caution (isn’t that better than carefully
again?) as you guide the PCB connecting wire andplug back on through the access way (or “hole”)
and replug (is that a word?) it back into the mating
socket.
3e. Place the top portion of the chassis over them
motor assembly, making sure not to make contact
with the motor, and replace screws to secure the
top of the head/shell to the mounting platform andmic chassis.
3f. Replace the bottom portion of the shell to thechassis, again, “carefully” noting the orientation of
the graphics and impedance switch which is a tight fit so gently nudge it into
place and replace the last two screws to hold it all together.
That’s All! Now let your girlfriend finish tracking that Joplin cover. But thistime use a GT Pop Filter!

VELO-8 Specifications
Microphone Type ..........................Velocity (Ribbon)
Operating Principle........................Electro-dynamic pressure gradient
Polar Pattern..................................Bi-directional (Fig-8)
Generating Element ......................2.5 micron corrugated aluminum ribbon
Ribbon Dimension ........................0.10” x 2.10” (2.50mm x 53.14mm)
Magnetics......................................Custom-Formed Rare Earth Neodymium
Frequency Response......................20Hz - 16kHz ±3db
Sensitivity......................................-50dBV Re. 1V/Pa
Selectable Output Impedance ......Low: 75 Ω, High: 300 Ω
Recommended Load Impedance....Low: 300-600 Ω, High: 1200-2400 ΩHigh Pass Filter..............................Apprx. 50Hz in rec’d low impedance window
Maximum SPL ................................138dB @ 0.5% THD
Output Connector..........................XLR
Polarity ..........................................Pin 2 hot for positive pressure (front of mic)
Dimensions ....................................8-1/4” long (20.5cm), 1-7/8” (4.7cm) max. dia.
Weight............................................1.3 lbs. (590g), mic only

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Groove Tubes Microphone Family

13

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:

GT Hardtop
3/4”x 6 microns
FET
HypercardioidTop
An affordable, high-quality stage vocal
mic with permanently attached ballwindscreen.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:

GT Convertible
3/4”x 6 microns
FET
HypercardioidTop
Winner of the 2006 TEC Award for bestsound reinforcement microphone, theConvertible is a true condenser thatswitches between a vocal or instrument
mic with a removeable ball windscreen.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:GT30
3/4”x 6 microns
Class A FET
Cardioid (omni & supercardioid optional)Top
Excellent on stringed instruments , overhead cymbals and vocalists who alreadyhave a deep voice . Great for close-miking
anything without proximity effect.Good
results for most other applications .

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:GT403/4”x 6 microns
Class A Tube
Cardioid (omni & supercardioid optional)Top
The ultimate acoustic guitar mic .
Exceptional on stringed instruments ,overhead cymbals and vocalists whoalready have a deep voice . Excellent for
close-miking anything without proximity
effect. Very good results for most otherapplications.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:

GT501.1”x 3 microns with Disk ResonatorClass A FET
CardioidTop
A classic fixed-position cardioid mic , withwarm Class A FET electronics. Good formale and vocals, choirs, pianos, ochestral
micing and other applications.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:GT601.1”x 3 microns with Disk ResonatorClass A Tube
CardioidTop
All sources will benefit from its tube
warmth and character.use it for leadand backing vocals, guitars, strings, andanything else that benefits from a tube
mic with a set Cardioid pattern.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:GT57
1.1”x 3 microns with Disk ResonatorClass A FET
Cardioid,omni,figure 8
Side
Excellent on vocals and grand piano. A
good all-around instrument mic .
Excellent sensitivity and pattern flexibility for duets, stereo and ensemble
recording.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:GT671.1”x 3 microns with Disk ResonatorClass A Tube
Cardioid,omni,figure 8,super-cardioidSide
Exceptional on vocals and grandpiano.A great all-around instrument
mic. Excellent sensitivity and patter n
flexibility for duets, stereo and ensem ble recording.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:

Model 1B-FET
1.1”x 3 microns
Class A FET
CardioidSide
Excellent on vocals. A great all-around
instrument mic.

Model:
Diaphragm:
Electronics:
Patterns:
Address:
Applications:

Model 1B
1.1”x 3 microns
Class A Tube
CardioidSide
Exceptional on vocals. A great all-around
instrument mic.

VELO-8 REFERENCE MANUALGroove Tubes Microphone Peripherals

ViPRE: Groove Tubes’award-winning microphone preamplifier.
Variable impedance input • Variable rise time • All tube, balanced Class A design •Precision gain control • Authentic VU metering

SuPRE: Stereo tube mic and instrument preamplifier.
• Two-channel stereo microphone and instrument preamplifier • Variable transformer
impedance settings on each channel • 72dB of gain on each channel

The Brick: Tube preamplifier, line driver, and DI.
• Tube mic/instrument pre for the studio and stage • Can run 1000 feet and more without
the losses of simple direct boxes. • High-quality sound • Sturdy construction

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