We realize that
you have a choice
in loudspeakers,
and are thrilled
that you have
chosen the
Imagine-series
component
systems. For more
information about
Hybrid Audio
Technologies,
our philosophies
regarding
high-end mobile
audio, to learn
more about
our lifetime
guaranteed value
program, and
for information
about our other
products, please
visit us at:
hybrid-audio.com
Speaker development is our passion!
When installed and set-up properly,
the Imagine Component System
you have purchased will make a
remarkable improvement in the
sound quality of virtually any mobile
audio sound system and give years of
superior performance.
With the publication of this manual,
it is our goal to assist the “do it
yourself” enthusiast and professional
installer alike in getting the highest
level of performance out of Imagine
Component Systems using straightforward installation advice.
Your Imagine system
contains speaker drivers
and a tweeter passive
crossover network
that were developed
and assembled with
a signicant eort
in research and
development, materials
science engineering,
an exhaustive level of
sampling and prototyping,
real-world testing, and
obsessive attention to
detail. The specications
and parameters of your
Imagine component system
is detailed on these pages.
Midbass Attributes
Imagine I5V2, I57, I6V2 & I69V2
Frame
Cast ABS plastic. The basket is a high-quality cast
ABS design, which plays a critical role in aligning the
voice coil in the magnetic circuit. Additionally, the
cast ABS frame allows for better clamping strength
verses typical stamped steel frames, and ensures
that the voice coil remains centered in the former.
The frame is a shared technology with the Unity
component sets, and allow for immediate upgrade
potential in the 5 1/4-inch and 6.5-inch format, due
to identical size footprint, mounting depth, bolt
circle diameter, and motor diameter as the Unity
systems.
Cone
Pressed paper with water proof treatment. It is
widely acknowledged that pressed paper cones
are the best marriage of lightness, stiness, and
ability of the cone to damp unwanted cone and
edge modes and resonances (read: distortion). The
paper cone, known for its excellent sonic attributes,
is water proof, thanks to a polymer developed
exclusive and proprietarily by Hybrid Audio
Technologies. The treatment does not change the
look and parameters of the driver like old-fashioned
“glossy” polymers which added an appreciable
amount of moving mass and signicantly colored
the sound. No, the Imagine cones look like any
“normal” paper cone, but in reality are likely the
only high-performance water proof paper cone car
audio speaker systems on the market. The treatment
protects the cone from periodic drips (such as inside
a door panel), as well as accidental splashes to the
front of the cone. On the hybrid-audio.com website,
we have hosted a video of an actual water-proof
demonstration where we pour two liters of water
over an Imagine coaxial, and then connect it to a
musical source. That video may be viewed at:http://
hybrid-audio.com/imagine/
Phase Plug (except I57-2)
Cast ABS plastic. When using the midbass in
component set mode (Imagine I51-2, Imagine
I61-2, and Imagine I69-2), the tweeter pole piece
is replaced with an ABS extended phase plug
pole piece. The extended phase plug pole piece
is critical for focusing high-frequency information
at the center of the cone. This design ensures
the speaker’s response remains linear into the
lower- to mid-treble frequencies. When using the
5 X 7-inch midbass in component set mode, the
tweeter bridge is removed from the midbass and
the Imagine I1 tweeter kit, sold separately, can be
mounted remotely.
Surround
Inverted high-loss rubber surround. The inverted
high-loss rubber surround (in concert with the
spider, detailed below), helps to provide the
compliance and “restorative force” needed for the
Imagine drivers to play eectively into the lower
midbass, and even upper subbass frequencies
(depending on in-car cabin gain and other factors).
You’ll also know a Hybrid Audio midrange and
midbass design by its inverted surround; this
design feature allows for the use of a smaller height
grille, better clearance with OEM panels, and more
exibility in mounting options.
Spider
Phenolic fabric and tinned tinsel leads. The spider is
the brownish/yellow corrugated (rippled) fabric that
attaches the cone and voice coil. The spider for the
Imagine designs was the subject of a considerable
amount of our research and development. The
spider is a phenolic symmetrically-rolled fabric
which provides excellent restorative force during
excursion. The spider is vented courteous of the
speaker frame; a design element not typically found
in this price range of speaker system. The spider
venting increases the thermal power handling of
the Imagine midbass driver. The tinsel leads are
connected to real epoxy PCB, not imsy cardboard.
Voice Coil and Motor System
The voice coil used in the Imagine midbass is a
2-layer aluminized copper wire coils on a round
former. An “overhung” voice coil was selected to
improve sensitivity while still keeping distortion to a
minimum.
Your Clarus system
contains speaker drivers
and passive crossover
networks that were
developed and assembled
with a signicant
eort in research and
development, materials
science engineering,
an exhaustive level of
sampling and prototyping,
real-world testing, and
obsessive attention to
detail. The specications
and parameters of your
Tweeter Attributes
Imagine I1
Dome
Small diameter impregnated silk textile dome
with high-loss rubber suspension. The I1 has
an impregnated ne cloth silk dome diaphragm
for a linear, smooth sound, with a high-loss
rubber suspension to damp edge modes and
resonances. The dome is of extremely low mass
and is much less susceptible to mechanical
deformation than other designs, and yet
yields a smooth response over the extent of its
range. At Hybrid Audio Technologies, we feel
larger diaphragm tweeters sound heavy and
unremarkable, lack detail in the upper treble
frequencies, have undesirable polar response,
and are dicult to install. Additionally, we
nd metal dome tweeters to be harsh, brittle,
and sound unrealistic. As a small diameter,
soft-dome tweeter, the I1 is the antithesis of
large diaphragm and metal-dome tweeters, for
the eective and convincing reproduction of
treble frequencies.
depth. A perforated grille protects the dome.
The voice coil is ferrouid cooled and damped,
and the tweeter housing consists of extruded
plastic with three dierent mounting options
in component set mode, giving the end-user
exibility in not only placement of the I1 but
also in physical installation.
Tweeter Passive Crossover
Low-Tolerance Mylar Capacitor. The tweeter’s
protection circuit and crossover lter is a very
high-quality, low-tolerance Mylar capacitor
that has been axed to the midbass frame. An
outboard crossover “box” is not included for
empirical reasons, explained here:
The set ships as a coaxial, and is ready to
install. Should the end-user want to connect
the tweeter in component set mode, simply
unscrew the tweeter, remotely mount the
tweeter, and extend wiring back to the midbass
terminals for re-connection to the tweeter
Thiele/Small Parameter Discussion for
Imagine Midbass Speakers
The mechanical and electrical parameters of
the Imagine midbass speakers are amenable
to a variety of dierent installations and
speaker locations. The high Qms (Q factor of
mechanical system) and Qts (Q factor of total
system), coupled with the driver’s Fs (resonance
frequency) allow it to be used in an “innite
bae” conguration. In more practical terms,
install the Imagine midbass such that the
front and back waves don’t “meet” (as detailed
in Section I – Getting Started - Basic System
Installation), including in a door or kick panel,
or in the case of a motorcycle, in the fairing
(using only the airspace behind the speaker as
a pseudo enclosure), with no need for a real
enclosure or “box.”
.
Clarus component system
is detailed on these pages.
25mm complimentary design. The motor
assembly is “conventional dynamic”, with a
compact neodymium magnet structure to
ensure a small footprint size and shallow
output posts. Refer to pages 26 and 27 for
more details on how to convert from coaxial to
component set, as well as view an informational
video here: http://hybrid-audio.com/imagine/
9
Imagine
Component
Systems
Specications &
Parameters
† Typically, in-car response including vehicular “cabin gain”, or the gain expected with
midbass installed in the vehicle, will result in an extended midbass and upper subbass
response. This is a result of these frequencies being below the lowest resonance in the
vehicle (typically around 50-125 Hz in most vehicles, described in more detail later in
this manual). In more practical terms, install the Imagine midbass into your vehicle and
you will see a dramatic improvement in midbass and upper subbass output, much more
so than just simply listening to the Imagine in a large room, or worse yet, “free air” (we
don’t recommend even trying the Imagine speakers in “free air” without some form of
enclosure or innite bae for the midbass).
Overall DiameterΦ150 mm140 x 198 mmΦ164.7 mm167 x 239 mm
Mounting Depth69.5 mm76 mm69 mm85 mm
Bolt Circle DiameterΦ139.5 mm125 x 117 mmΦ156 mm131 x 163.5 mm
Mounting HoleΦ 123 mm125 x 183 mmΦ 140.7 mm150 x 224 mm
Recommended Minimum Highpass
Crossover Frequency (fourth order)
Continuous Power Handling
(Pnom Rated Power Input • No crossover)
Peak Power Handling
(Pmax Rated Power Input • No Crossover)
Recommended Power Range20-150 watts20-150 watts20-150 watts20-150 watts
As mentioned in the Welcome and
Introduction, this is not your typical
car stereo speaker owner’s manual.
It is a mobile audio reference manual
for not only your impending Imagine
installation, but also to act as a guide
to get the most out of your audio
system. Generally speaking, this
manual is divided into two parts.
The rst part focuses on a typical,
basic installation of the Imagine
product, and follows in general what
you’d expect from a mobile audio
component system owner’s manual.
The second part delves into more
advanced topics on optimized speaker
placement, “lessons learned” (a topical
discussion of real-world applications),
use of sound damping products and
acoustic absorption materials, and
ne tuning. Most users will stop at the
conclusion of the rst section once
the basic installation is complete, and
this is perfectly acceptable. But for
those with an intrinsic desire to learn
more about how to make their mobile
audio systems better, we invite you to
continue reading through the latter
half of the manual as well. Our goal is
to not only build the best-performing
mobile audio systems in the world,
but to also educate consumers and
professional installers alike on how
to achieve reference-grade audio
system playback in the mobile audio
environment.
Carefully unpack the Imagine carton, and verify that the
following parts are included in the box (CAUTION: use care
to remove the midbass speakers with two hands, and avoid
pressing your thumb or ngers against the cone of the
midbass – never test the speaker’s excursion manually with
your ngers by pressing the cone):
• Two Imagine midbass speakers with integrated tweeter
crossover; and
• Imagine I1 25mm tweeter speakers pre-installed in coaxial
mode.
The following items are also included in the Imagine I51-2
(including V2), Imagine I61-2 (including V2), and Imagine
I69-2 (including V2) kits:
• Two midbass grilles with anodized aluminum Hybrid
Audio Technologies nameplates and ABS grille mounting
anges;
• Nine small packages located underneath the midbass
drivers in, which contain parts for use as a component
system, including
• Two tweeter surface-mount cups;
• Two tweeter ush-mount cups;
• Two tweeter angle-mount cups;
• Two ABS extended phase plug pole piece extensions
(bullets);
• Tweeter and midbass mounting hardware including two
silver plain steel tweeter retainer clips (attaches to the
back side of the ush-mount tweeter cup to keep the cup
solidly installed), machine screws and set screws for the
retainer clips, and hardware needed to install the midbass
speakers, including high-quality black oxide Philips head
screws black anodized screws to mount the midbass
speakers; and
• A pair of replacement magnet decals.
Should you be missing parts, please contact your
authorized Hybrid Audio Technologies dealer for
replacement parts, or contact us directly at: support@
hybrid-audio.com
Basic System Installation
Now that you have unpacked the Imagine box and have veried that all of the parts are
included, it is time to evaluate the vehicle for the impending installation. If you feel the
least bit uncomfortable about the installation, have the Imagine speakers installed by
an authorized Hybrid Audio Technologies dealer. The Imagine speakers are an incredible
high-end speaker system, but will only be as good as the installation; a poor installation
can negatively aect the performance of the Imagine speakers. We can only build great
speakers, but can’t control or account for poor or inadequate installations.
Should you decide that you can handle the installation yourself and feel condent that the
end result will be adequate to reap the performance benets of the Imagine component
system, you will need to have certain hand tools available to you for the installation. These
include, but may not be limited to:
• Cordless drill/driver with a 1/8” drill bit and a Phillips head and a few assorted driver bits
(commonly including Torx driver bits) with an attachment (a hand-operated screw driver
and/or Torx driver will also likely work);
• Certain vehicles may require an assortment of hex-key wrenches to remove the old
speakers and/or panel screws;
• A panel-popping tool (retaining clip removal tool) to remove panels in the vehicle
(such as door panels). In a pinch, a large at-head screwdriver does work, but damage to
panels or retaining clips can result;
• A wire cutter and wire stripper;
• Electrical tape; and
• If you plan to use the vehicle’s existing speaker wire, you will need to know which wire
is positive and which is negative at each proposed speaker location. If you’re unsure, we
highly recommend the use of Installation Excellence, an on-line resource for wire colors,
wire locations, t guides, and technical support.
In a basic system, the Imagine midbass speakers were designed to be installed in the
original factory speaker locations, most often in the vehicle’s doors (more advanced
locations that provide an additional level of performance are discussed in Section II of this
manual, if you’re interested in learning more). The Imagine midbass drivers are innite
bae-capable speakers, and must be mounted in a “large enclosure”, or as close to it as
possible, with unrestricted access to airspace to ensure the speaker’s ability to eectively
reproduce its wide frequency bandwidth. The reason why the speaker was designed in
this way is highly empirical. When a speaker is mounted in a small closed box, it radiates
as much energy forward of the cone as it does rearward of the cone. All speaker cones
(diaphragms) are a weak sound barrier at best, and the result of the high amount of energy
being “pushed” into a small enclosure is the energy transmitting through to the outside
of the cone (an additive phenomenon to the incidental wave). Consequently, Hybrid
Audio has designed the Imagine midbass to work well without an enclosure, and as such,
should not be signicantly prone to enclosure back-pressure and sound coloration when
placed innitely baed. The “innitely large” enclosure, such as one might nd in a door
An Important Learning Note
Hybrid Audio Technologies designed the Imagine-series to be used predominantly as a coaxial, as we
can eectively mitigate anticipated environmental conditions and reduce the number of variables in
this type of installation. When used as a coaxial, the relative amplitudes (volumes) of the midbass and
tweeter are equalized to each other and the speaker system will perform as intended. There is much
less amplitude control of the tweeter amplitude with respect to the midbass amplitude when the set
is converted into component set mode. This is due to simple physics. If the midbass drivers are placed
low in the door, for example, and the tweeter is placed high in the dashboard, sail panels, or a-pillars,
there WILL be a notable amplitude dierence between the two speakers. This is because the midbass
are installed further from you, and are likely aimed into your leg, carpeting, and other soft furnishings in
the vehicle, while the tweeter is located likely closer to you, likely aimed more “on-axis”, and is near hard,
reective surfaces, such as window glass, hard plastic interior panels, and etc. In many cases, converting
from coaxial to component set will cause the tweeter to be notably louder than the midbass. This is not
a speaker malfunction; it is a simple acoustical phenomenon playing out in your vehicle. Hybrid Audio
Technologies usually recommends that the Imagine sets be left as a coaxial, but encourage the end-user
to test the Imagine systems in both formats to evaluate what best suits the end-user’s listening habits.
panel, improves spectral response and power response variation between high and low
frequencies.
In a basic system, like the Imagine midbass, the Imagine tweeters were designed to be
installed coaxially with the midbass, or as a component system in the original factory
tweeter locations, such as those typically found in many newer-generation vehicles, most
often at the top of the door, or in the “a-pillar.” Conversely, many will nd that the I57-2
is a direct drop-in t in many Harley Davidson® motorcycles. The obvious “path of least
resistance” is to leave the Imagine speakers in their coaxial mode. If you do decide to use
the Imagine set as a component system, and if your vehicle is older, or did not come with
factory tweeter locations, you may need to install the tweeters in a bit of a custom fashion.
Not to fear though – we have included several dierent options for easily mounting
the tweeters, so you can decide which will work the best for your application. Since the
tweeters are a sealed-back design, they can be placed anywhere without having to provide
airspace or any type of enclosure.
Hybrid Audio Technologies highly recommends that the tweeter placement be the subject
of your own experimentation. This can be accomplished by leaving some excess wire
NOTE: Should the end-user be interested in a Hybrid Audio component set which includes Stage II
Imagine and Stage IV Clarus-level enhancements, which includes tweeter level attenuation, we’d
recommend the Stage III Unity series. The Unity series is a melding of the best of the Imagine line with
Clarus-level enhancements to make a budget-friendly high-end alternative; Hybrid Audio loosely calls
the Unity line ‘Clarus Junior.’ The Unity kits include the best features of the Imagine-series components,
including the same cast ABS frame, spider, and water-proof cone used in Imagine systems. Clarus-level
enhancements include outboard crossovers containing high-quality, low tolerance polypropylene and
electrolytic capacitors and air-core inductors, PTC tweeter power protection, and three steps of tweeter
attenuation, encased in the Clarus competition crossovers housing with gold-plated screw terminals.
Unity systems also utilize the exceptional Clarus C1 competition-grade tweeters for a step-up in
performance over the Imagine tweeter oering.
Finally, just because there is a factory tweeter pod location in the dashboard, a-pillars, fairing, or sail
panels in your vehicle doesn’t mean you have to use it! Because our ears are on the left and right sides of
the human head, human hearing is much less susceptible to hearing height cues as it is hearing width
and depth cues (please reference Lesson 3 and Lesson 4 later in this manual). Please don’t be fooled into
thinking that the tweeters MUST be placed high in order to establish a good stage height! Alas, as the
length for the tweeter, and experimenting with dierent potential mounting locations by
temporarily attaching the tweeter using double stick tape, Velcro®, etc.
end-user, it is up to you to take the time and test the set to see what orientation is to your liking, and
certainly, as students of acoustics, we at Hybrid Audio Technologies encourage that learning exercise.
25
Section I • Getting Started
Need more assistance or still having trouble visualizing the conversion? Then check out our
video which details how to convert your coaxial into a component system, which can be
Coaxial / Component Set Conversion for I51-2, I61-2, and I69-2 (including V2)
At this juncture, you must decide if you want to install the Imagine set as a coaxial, or as a
component system. If you opt to continue on as a coaxial, you can disregard this section. If
installing as a component system, read on.
Here are a few very simple steps to convert your I51-2 / V2, I61-2 / V2, or I69-2 / V2 coaxial
into a component set:
1. Remove both midbass’ from the Imagine carton and ip them upside down on a clean,
non-abrasive surface such as a kitchen table. Use a towel to protect the tweeter.
2. Peel the Imagine decals o of both of the midbass magnets. You will now see a small
screw in the dead center of the magnet. This screw is holding the tweeter and the tweeter
pole piece (the “platform” the tweeter is attached to) in place.
3. Disconnect the tweeter’s wires from the midbass’ terminals. Note that red is positive and
black is negative.
4. Put the midbass in your hand and softly cup the tweeter in the palm of your hand. Use
a 3mm hex wrench (Alan-head wrench) to remove the screw and allow the tweeter pole
piece to drop out from the front of the midbass into your hand. Pull the speaker wire
viewed here: http://hybrid-audio.com/imagine/
Coaxial / Component Set Conversion for I57-2 Harley Davidson® Drop-In
Here are a few very simple steps to convert your I57-2 coaxial into a component set:
1. Remove both midbass’ from the Imagine carton and ip them upside down on a clean,
non-abrasive surface such as a kitchen table. Use a towel to protect the tweeter.
2. Disconnect the tweeter’s wires from the midbass’ terminals. Note that red is positive and
black is negative.
3. Put the midbass in your hand and softly cup the tweeter in the palm of your hand. Note
small #1 Philips head screws holding the tweeter bridge in place. Remove these screws
and allow the tweeter bridge to drop out from the front of the midbass into your hand.
Pull the speaker wire through the midbass’ wire routing channel.
4. Purchase the Imagine I1 tweeter kit, which includes a second set of tweeters with
hardware, and extend some speaker wire length between your tweeter location back to
the midbass, and re-connect (red to positive and black to negative).
through the midbass’ magnet. DO NOT DISCARD THE SCREW!
5. Locate the extended phase plug pole piece in the kit (looks like a bullet), and insert the
bullet into the magnetic gap the same way the tweeter pole piece used to be inserted.
Secure the extended phase plug pole piece bullet with the screw you just removed.
Tighten securely, but don’t over-tighten. Note, the screw is the perfect length to snug
the pole piece to the former. DO NOT shorten the screw or use a dierent screw! The last
several turns of the hex key actually “cut” threads into the phase plug, ensuring that it does
not come loose over time. Keep turning the screw until the phase plug is secure. Please
visit our site or our YouTube channel for more details and a video.
6. Locate the magnet decal in the Imagine carton and replace the decal to the magnet of
the midbass. The decal doesn’t need to be installed if you want to skip this step.
7. Extend some speaker wire length between your tweeter location back to the midbass,
and re-connect (red to positive and black to negative).
a pattern around the speaker until all screws are hand-tight. DO NOT INSTALL THE SPEAKERS
WITH A DRILL OR DRILL-DRIVER, as the drill-driver will put considerably more torque on the
Installation
Once you have determined the mounting locations for the Imagine separates, and have
evaluated the circumstances by which the Imagine speakers will need to be installed, it is time
to dismantle the vehicle to access the old speakers. Most dashboard-mounted speakers are
easily accessed by removing their grilles, which are usually attached to the dashboard with
screws or retaining clips. A-pillars are usually accessed by pulling rmly at a right angle to the
panel. Door speakers are usually easy to access as well, either from the front by prying o the
OEM grille, or by physically removing the entire door panel. In all cases, it may be prudent to
reference your vehicle’s factory service manual. If you don’t have a factory service manual, you
can go to the Installation Excellence website for downloadable resources with respect to not
only wiring but disassembly of your vehicle, and the procedures to access your OEM speakers.
With the OEM speakers removed, we HIGHLY recommend the use of a self-adhesive damping
product, such as brand names Dynamat®, B-Quiet®, RAAMmat®, and others. The reason for the
use of damping material is to quiet buzzes and rattles that will be exposed by the high-perfor
mance Imagine midbass speakers, but more importantly to seal up door accesses and cavities,
thereby creating a pseudo “enclosure” for the Imagine midbass. If the midbass are installed
speaker basket than what is required, and can easily damage the frame of the speaker.
In the event a component set mounting topology is chosen, the same procedure can be
followed for the tweeter installation observing the precautions mentioned in the midbass
installation, above. Once a suitable location is found for the tweeters, mounting options
can be evaluated. The I51-2 / V2, I61-2 / V2, and I69-2 / V2 kits come standard with three
tweeter mounting options, including a swivel ush-mount cup, a surface-mount cup, and
an angle-mount cup (the component set tweeter is optional for the Imagine I57-2). The
tweeter ts rst into the surface-mount cup, and then can be installed as one unit into the
ush-mount cup. Conversely, the surface-mount cup can be attached to the angle cup as well.
In all cases, the tweeter is tted into the surface-mount cup rst, and then either installed
as-is, or is further encased in the ush-mount cup, or is attached to the angle-mount cup.
Decide which mounting strategy works the best for your installation, and permanently mount
the tweeters. Route the wiring from the underside of the tweeter to an accessible location
and connect to the tweeter connections (small diameter slide terminals) on the midbass
frame.
Once all four speakers are installed, you will need to do a brief listening test with CD-quality
immediately adjacent to a large access hole or opening in the door panel, there will be an
acoustic “short circuit” (as described later in “Frequency Response”) where the front and back
waves of the speaker meet, and cancellation will occur, seriously aecting midbass output.
The use of a good damping product is the single-biggest installation-related improvement
you can do to enhance the performance of your Imagine audio system. And since the Imagine
midbass require an “innite bae”, it is intuitive to seal up the mounting area as best as
possible, such as in the door, allowing the speaker to “see” a large enclosure in the door cavity,
kick panel, dashboard, or wherever you decide to mount the Imagine midbass.
If you plan to use the OEM speaker wiring, you will likely need to cut o the OEM speaker
plug, and strip back approximately 3/8” (10mm) of insulation to expose the bare wire. It is
recommended that you then install slide-style terminals on the wire, for easy connection to
the Imagine midbass.
In a basic installation, the Imagine midbass were designed to install directly into the factorysupplied speaker baes or speaker openings. The speaker should t snug to the bae
without air gaps; do not force the speaker into a bae that is too small, as this will damage
the speakers. If the factory-supplied mounting bae is too small, refer to Section II for advice
on how to build custom baes. When tightening your speakers to the bae, alternate the
music that you are intimately familiar with to determine if the tweeter seems to be linear in
amplitude with the midbass, or seems to be too muted. If the tweeter seems too muted, or
if you prefer a louder tweeter sound, simply reverse the black and red wires on the tweeter
terminals located on the frame of the midbass. You will be changing the polarity of the
tweeter, and will be increasing the loudness of frequencies between approximately 6,000 –
10,000 Hz by doing this.
Once all four speakers have been installed and the level set as per the above, the sound
damping cropped so as to allow for the re-installation of door panels and/or interior panels,
and all wiring neatly wire-tied away from heat and noise sources, or from abrasion and areas
where the wires may be accidentally sliced or cut, the vehicle can be re-assembled. Sit back
and enjoy the music
This is the end of Section I: Basic Installation.
If you’re happy with the end product, stop reading here. If you
want to learn more about advanced techniques for achieving great
mobile audio sound quality, ip the page...
tightening of the screws, just as if you were changing a tire on your vehicle, by alternating in
The previous section detailed a typical, basic installation of the Imagine product. In this section,
Hybrid Audio Technologies has prepared a more advanced topical discussion of Imagine
installation techniques, concepts, and principals, where a little bit of additional installation work
can net immense gains in overall sound quality.
There are certainly many things you can do to improve your mobile audio system, such as addition
of amplication, a dedicated subwoofer system, higher-gauge speaker wire, and higher-end
Lesson Two: Equalization of Pathlength Dierences
Quite possibly the most important functional consideration that a do-it-yourself enthusiast or professional
installer should give to the Imagine speaker placement is to optimize, as best as possible, pathlength
dierences (PLD’s) in the vehicle. PLD’s are dened mathematically as follows (this example assumes a
right-hand drive vehicle---PLD’s are always a positive number):
X – Y = Z
Where:
X = distance of the center of the left speaker from your left ear.
Y = distance of the center of the right speaker from your right ear.
Z = pathlength dierence.
passive crossovers, and active crossovers. All of these things require an additional amount of
monetary investment into your audio system, and may not net the immediate gains that other,
more elementary installation items can net. The following discussion is pertinent to easy and
cost-eective enhancements you can do for your audio system, particularly as it relates to the
installation of Imagine component speakers.
In any mobile audio system, the weakest link will always be the speaker systems, followed closely
by installation techniques (sometimes its vice-versa). Since the Imagine component system you
have purchased has solved the rst issue, the second issue, that being installation techniques,
can see a signicant improvement as well by understanding and incorporating some or all of the
techniques in the following sections.
Lessons Learned
We like to call this our “Lessons Learned” section, where we expose some critical lessons that we
have learned through thousands upon thousands of hours of trial and error:
Lesson One: O-Axis Response
Applying this formula, assume that the distance of the left speaker from your left ear is 140cm, and the
distance of the right speaker from your right ear is 100cm, the pathlength dierence is 40cm.
Good stereo imaging is completely dependent on arrival times of the fundamental vocal frequencies.
Dierences as little as 10 microseconds can be detected by the brain. A PLD of 30 centimeters equates to
the sound from the nearest channel arriving about 0.9 milliseconds earlier than the furthest channel. It is
Hybrid Audio’s opinion that the end-user should try to keep PLD’s to less than 30 centimeters in a vehicle
which is intended to have good imaging and staging character from both seated positions.
The best way to go about evaluating certain locations in your vehicle is, in general, to look for the potential
locations as far forward and away from you as possible, but still with a general “line of sight” to the speakers
(particularly the speaker on the far side of the vehicle). An easy way to test various potential locations is
to hold a tape measure or other measurement device from the potential speaker mounting locations, and
measure those locations with respect to your ears.
Reference the gure, below. In this scenario, three potential locations for the mounting of the Clarus
midbass driver are shown:
When a speaker system like the Imagine is placed in an automotive environment, we hear the
direct (shortest path) and reected (longer path) sounds, such as resonances and reverberations.
The two sounds are processed by the brain as one sound, and this inuences our perception of
height, width, and depth of soundstage, as well as rearward ambience. For this reason, the o-axis
radiation pattern of any speaker in a vehicular environment has a signicant inuence on how
natural the music sounds.
The lesson to learn here is that most mobile audio sound systems benet greatly from having the
front stage speakers at least partially “o-axis.” O-axis means that the speakers are not pointing at
you, but rather at some angle less than 90 degrees away from you.
Figure 1: Potential Locations for Mounting the Imagine Midbass Speakers
31
Section II • Moving Forward
A sound wave approaching the eardrum from your chosen speaker location is shaped by
interactions with the size and shape of your head, torso, and outer ear, resulting in the HRTF.
Lesson Two: Equalization of Pathlength Dierences (Continued)
In scenario “a”, we show the installation of the Clarus midbass in the dashboard, high in a door
panel, or in the a-pillar. As you can see from the diagram, the PLD’s between the left and right
speakers are large, due to the proximity of the listener to the near-side speaker. While the
mounting of primary drivers in the dashboard or a-pillars has become increasingly popular, this
conguration will undoubtedly require both time and intensity domain equalization in most
vehicles to ensure a good, focused center image, properly located in the center of the vehicle for
one seated position. There are, however, some rare exceptions, and you may actually nd that the
dashboard locations provide the best equalized PLD of the available mounting locations; this is
very rare though – in our experience, less than one percent of vehicles on the market today have
optimized dashboard speaker locations for the midbass drivers.
In scenario “b”, a typical door installation location is shown, and in many vehicles represents a
good improvement in PLD’s from the dashboard, high in the door panel, and a-pillar location
identied in scenario “a.” The door speaker installation scenario is the one detailed in the basic
installation section at the beginning of this manual, and in most vehicles represents a satisfactory
location to mount speakers; not ideal but satisfactory. The door speaker installation scenario will
likely also require some amount of time and intensity equalization to ensure a centered image in
most vehicles; this can be as simple as adjusting the balance control on your source unit, to more
More specically, the HRTF is the ratio between the sound pressures of the wave at the eardrum,
as compared to the sound pressure that would exist at the center of the head if the head were
removed. In general, the sound arriving at the ear further from the source is attenuated and
delayed relative to the sound arriving at the ear closer to the source. This generates an interaural
intensity dierence (IID) and an interaural time delay (ITD). As a sound approaches the head, the
ratio of distances from the speaker location to the near and far ears increases, and the eects of
head-shadowing are amplied, causing the IID to increase. The spectral shaping caused by the
head and the shape of the outer ear may also change. The ITD, which results from the absolute
dierence in path length from the source to the ears, remains approximately constant as distance
decreases. From this we learn:
• ITD is the dominant factor for frequencies below about 500 Hz;
• A combination of ITD and IID are dominant for frequencies between approximately 500 Hz and
2,000 Hz; and
• IID, in concert with HRTF, are dominant above about 2,000 Hz.
These are generalizations, and are subject to the size and shape of one’s head and torso, and size
and shape of the outer ear (the folds and ridges of the ear), but in general, the above is a good
guideline for establishing ITD, IID and HRTF thresholds for the human auditory system.
advanced ways of digital time and intensity manipulation.
The third and nal potential mounting location as shown in this diagram (scenario “c”) represents
a kick panel installation, where the midbass are placed far forward in the A-frame cavity of the
kick panels, present in most vehicles. The kick panels are the small panel next to the throttle and
brake pedals, down by your feet. While it is not immediately obvious looking at a two-dimensional
drawing, in many cases the kick panel location aords the best equalization of pathlength
dierences for most vehicles. And the reason why this is a good choice for most vehicles is dened
in the second full paragraph of Lesson Three, below.
The lesson to be learned here is that by taking a few moments to evaluate the potential mounting
locations in your vehicle, in a very short period of time, you will be able to nd the best location for
your Imagine midbass by determining the location with the smallest PLD.
Lesson Three: The Eect of HRTF, ITD, and IID
Head-related transfer function (HRTF), interaural intensity dierences (IID), and interaural time
delay (ITD) all play a key role in the optimum placement location for the Clarus component
speakers.
Because the Imagine midbass’ ability to play into the sub-200 Hz range, an eect clearly dominated
by ITD, up to and including frequencies exceeding 6,000 Hz, an eect clearly dominated by IID
and HRTF, placement of this driver is extremely important. The driver should be placed as far
forward as possible in the vehicle to optimize ITD. Lateral (forward to back) placement is much
more important than horizontal placement (up and down). This is because of the brain’s ability to
process sounds such as spectral envelope cues, and use a phenomenon known as the “precedence
eect”; the brain can be easily “fooled” into thinking a sound stage is high with kick panel or
oor-mounted speakers (a word to the wise: the best place to put a set of speakers is not always
“up high”, as most vehicles do not oer an amicable location in the dashboard or a-pillars for good
image placement for both seated passengers, especially in the critical frequencies sub-500 Hz).
In addition to the time equalized placement of the drivers, the end-user must also consider that
above approximately 2,000 Hz, intensity plays a key role in good sound staging and imaging.
Therefore, the Imagine midbass’ should be placed in an area where intensity dierences can be
equalized, either mechanically or electronically, to ensure good imaging and sound staging.
The lesson to be learned is that, like Lesson Two, the Imagine midbass should be placed as far
forward from your listening position as possible, and every eort should be made to optimize time
and intensity domain characteristics of the installation.
no sonic benet to your Imagine installation. The Imagine drivers are long-throw midbass, and the
plastic mounting baes that come from the factory in virtually every vehicle will lead to buzzes,
Lesson Four: Point-Sourcing
The term “point-sourcing” is often used to describe the technique of having a single pair of
speakers in an installation cover the majority of the critical middle band frequencies. In many
installation scenarios, the Imagine midbass could be considered a point-source speaker driver,
because it has the ability to reproduce six octaves of tones. Point-sourcing, if done correctly,
can lend itself to a variety of valuable attributes, including precise image denition and stable
sound staging character. By applying Lessons 1-3 above, the Imagine midbass can be used as a
point-source driver to achieve excellent staging and imaging results.
The lesson to be learned here is that the Imagine midbass, given its wide-bandwidth design, can
faithfully reproduce as much as six octaves of tones, and would make a valuable addition to any
sound system as a point-source driver for the spectrum comprising vocal imaging cues.
Lesson Five: Reference
One of the most important things to do before completing your Imagine installation is to get a
reference for your future listening tests. To really know what a snare drum sounds like, you must go
rattles, vibrations, and resonances, all of which negatively aect the Imagine installation. In other
vehicles, you may have attached the Imagine midbass’ directly to the door metal (hopefully with
a layer or two of self-adhesive sound damping in between), but this is still not entirely ideal.
In whatever scenario you have installed your Imagine midbass, there are certain “tricks” and
techniques that may be applied to get the most out of your Imagine component set, specically
the midbass installation, as follows:
Mounting the bae, sound damping, and “decoupling”
The mounting bae or mounting location should either be secured extremely well to the vehicle’s
body, or completely isolated from the vehicle’s chassis. The reasoning is that the speaker bae
panel will vibrate and will radiate sound. Even small vibrations can result in the bae itself
radiating more sound than the actual speaker at certain frequencies. The mounting bae or
mounting location should be damped with a layer of typical sound damping to reduce the Q of
the bae and lower its vibration resonance frequency below the range of the driver’s frequency
response. In many cases, using thicker bae panel in concert with self-adhesive sound damping
can also be advantageous, provided the rearward wave of the speaker has no obstructions created
and listen to one, in person, live and un-amplied. There is no substitute for the visceral impact and
emotion of live music. Nothing else in life can touch your soul the way music does. Whether it’s a
200-member orchestra, or a four-piece fusion band, nothing compares to the phenomenon of live
music.
Take this as Hybrid Audio’s ocial request: become a student of music and your mobile audio
sound system will be better for it. We want nothing more than to know there are great sounding
audio systems around the world using our products, and you’d make us all very proud if you
became a student of music and learned its beauty and passion.
Advanced Installation of the Imagine Component
Systems
Mounting Bae Considerations
Now that we have revealed ve of our most important “Lessons Learned”, we can now apply these
lessons to the Imagine installation. The rst important matter is the physical installation of your
Imagine midbass, and more specically with respect to improving the Imagine midbass’ mounting
by the bae itself. Finally, if possible, the speaker should be mechanically decoupled from the
bae. This can be something as simple as a layer of self-adhesive foam tape, to more exotic
examples of decoupling, including rubberized rings or multiple-layer septum shielding.
Building solid mounting baes
In many cases, it is advisable to mount your Imagine midbass’ in high-stiness wood or
high-density berglass (or wood treated with berglass resin). Hybrid Audio Technologies
recommends the use of a solid hardwood, such as birch or oak, namely because these woods are
sti and help to dissipate resonance, and screws can be inserted and removed multiple times
without stripping. Avoid Medium Density Fiberboard (MDF), particularly in wet environments
like the door, as the MDF will act like a sponge with humidity and moisture, and not only that, the
MDF is a dense, but not sti type of wood, and the results may not be particularly noticeable if
you use MDF. Once your bae is built, it must be covered in one or two layers of a good-quality,
brand name self-adhesive damping product; a solid wood mounting bae with sound damping
treatment will augment the Imagine installation by eliminating resonances.
baes. Most vehicles’ factory mounting locations for speakers are less than ideal. In most cases, the
OEM speaker mounting anges are likely nothing more than imsy extruded plastic, and provide
The rst principle to understand is that below 200 Hz, acoustic treatments are rendered virtually
useless. It is Hybrid Audio’s assertion that only those frequencies above 200 Hz benet from the
Advanced Installation of the Imagine Component
Systems (Continued)
Mounting bae dimensions
While building baes is important, it is notable that mounting bae size is equally important.
All mounting baes should be kept as small as possible with respect to the size of the speaker.
The purpose of using a small bae is to avoid the potential for low amplitude diracted sound
waves becoming summed with the incidental waves. A narrower bae also becomes increasingly
important as frequencies range into the Imagine midbass’ upper bandwidth, where the power
response is more uniform and incident and reected waves are indistinguishable. In practical
terms, keep bae dimensions small with respect to the size of the Imagine midbass, chamfer or
round sharp edges (including, in particular, the mounting hole’s rear inner edge), ush-mount
the speaker whenever possible, and use shallow, surface-mounted hardware. Also, remove all
unnecessary protrusions from the bae surface.
Acoustic Treatment
A considerable benet can be made to any mobile audio system with the select placement of
acoustic treatments. The purpose of using acoustic treatments is to reduce the amount of reected
energy in the hostile automotive environment, and hear more of the direct sound being emanated
use of treatments, given that a 200 Hz waveform is about 1.7 m long; 1.7 meters is less than or
equal to most vehicle widths. This is also the frequency where we believe pure tones in the vehicle
are going to be dicult, if not impossible to localize. Finally, most vehicles exhibit a Schroeder
Frequency (Fs) between 50 at 125 Hz; the Fs (or cabin-gain frequency) is vehicle dependent, and
is the frequency at which resonances become so tightly packed in frequency and space that the
acoustical properties of the vehicle behave quite uniformly. (As an aside, one signicant benet
of car audio sound systems is that frequencies below the lowest room resonance increase at a
theoretical 12 dB/octave…it’s no wonder car audio systems have such great bass!)
Acoustic treatment can be very eective above 200 Hz, depending mostly on the polar radiation
pattern of the speaker. In the case of the Imagine midbass, the polar radiation pattern is quite large
at lower frequencies, with a narrowing of the radiation pattern (“beaming”) at frequencies into the
treble bandwidth.
Should the Imagine midbass be placed in the kick panel locations, one may nd that a notable
improvement can be made by adding acoustical treatments, such as open-cell foam, into the
underside of the dashboard. Likewise, should the midbass, or in fact the I1 tweeter be placed up
high on a-pillars, or in the dashboard, where comb ltering (reective summation and cancellation
o of a hard surface, such as a windscreen) may become an issue, a dashboard “mat” or other soft
furnishing may be a noticeable improvement. It will require trial and error to get it right, but the
learning is in the experimentation!
from the speaker. It is akin to the signal to noise (S/N) ratio in a piece of electronics, where the
signal could be considered the direct energy coming from the speaker, and the noise could be
considered the reected waves o of nearby surfaces, such as windows, hard center consoles and
door panels, windscreens, and etc. A word of warning though: there is a ne line between too little
and too much acoustic treatment; just as some vehicles can benet from some selectively applied
treatments, there is a point where the vehicle can begin to approach “semi-anechoic” conditions,
and lose its liveliness, which is not ideal. Reections are all around us, and are a part of our
day-to-day lives. It is our opinion that some lateral reection is a good thing; it helps to establish
stage boundaries, and gives the recoded playback and more visceral and “believable” sound.
Sadly, there are no rules in mobile audio, only several hypothesis and theorems that seem to work
for most vehicles. Your vehicle may be dierent, and defy everything we know, and everything
written in this manual. You may nd that getting that rich, detailed sound that you crave may
require some experimentation and a lot of work to make it right. Or you might be fortunate to have
a vehicle that sounds excellent with minimal work. Have patience and work through the issues;
the result will be a rewarding musical experience in your vehicle! Just remember, it is critical to get
a reference, as detailed in Lesson 5. Go out and become a student of music and audio, learn, and
improve your audio system one step at a time. The journey is exciting and rewarding!
What we have included above is only a very brief primer to the world of high-end mobile audio
systems. We invite you to read more by going to our downloads page at hybrid-audio.com.
37
Imagine
Hybrid Audio Technologies extends a limited
one year warranty to the original purchaser
period of the product on which the parts are
Thank You!
being used, whichever is longer.
Component
Systems
Warranty
when self-installed, and three years warranty
when installed by a certied Hybrid Audio
Technologies dealer (United States only),
and hereby certies that this product
will be free from defects in materials and
workmanship under normal and proper use
for one year from the date of purchase.
Hybrid Audio Technologies’ responsibility
under this warranty is limited to replacing
or repairing, at Hybrid Audio Technologies’
option, products or parts determined by
Hybrid Audio Technologies to be defective
either in materials, or workmanship. To
attain warranty service, the customer
must deliver the product or the defective
part(s), appropriately packed with proof
of purchase date, to an authorized Hybrid
Audio Technologies dealer. In the event that
a direct return from a consumer is required,
the consumer must obtain from Hybrid
Audio Technologies a return authorization
number, and ship the defective product
directly to Hybrid Audio Technologies.
All shipping expenses are the customer’s
responsibility. If the product has been
updated or superseded, a replacement
will be made with a current model of the
same quality and function. Warranty of
the replacement parts is limited to 90 days
or the unexpired portion of the warranty
This warranty does not cover any defects or
costs caused by: (1) modication, alteration,
repair or service of this product by any
persons or company other than Hybrid
Audio Technologies; (2) physical abuse to,
overload of, or misuse of, the product or
operation thereof in a manner inconsistent
with the use indicated in the instructions; (3)
any use of the product other than that for
which it was intended; or (4) shipment of the
product to Hybrid Audio Technologies for
service. This warranty does not cover labor
costs.
Hybrid Audio Technologies is not liable
for any special incidental or consequential
damages, including, but not limited to,
personal injury, property damage, damage
to or loss of equipment, loss of prots
or revenue, costs of renting or buying
replacements and/or any other additional
expenses, even if Hybrid Audio Technologies
has been informed of the prospect of
such damages. Any express warranty not
provided herein, and any remedy which
other than the warranty contained herein
might arise by inference or operation of law,
is hereby excluded and disclaimed including
the implied warranties of merchantability
and of the tness for a particular purpose.
Hybrid Audio Technologies is
delighted that you have chosen
an Imagine Component System
for your high-end mobile audio
sound system. We are convinced
that a great product oering,
backed up with unsurpassed
customer service and technical
support will advance the Hybrid
Audio Technologies namesake in
the coming years. We are pleased
that you have joined us in our
“new generation of in-car audio.”
If there is anything we can do
to help you get the most out of
your Imagine installation, please
do not hesitate to email us:
support@hybrid-audio.com,
by phone: 770.888.8200, or by
visiting us at: hybrid-audio.com