Motorcycle Intercom Speaker Replacement
BT Interphone Intercom Speaker Replacement
by Tim M. for webBikeWorld.com
Editor's Note: Many intercom
owners have been asking about how they might go about
replacing their original equipment speakers with
higher-quality speakers or earbuds.
Until the intercom manufacturers start offering more and better speaker
options, a DIY project may be the only solution.
We received this detailed report from webBikeWorld reader Tim M., who
replaced the original speakers on his BT Interphone intercom with a pair of
high-quality speakers from a Sony headphone set.
We thought this information might be of interest, so we decided to publish it
as a webBikeWorld Owner's Report.
A few items to note: We haven't tried to duplicate this project,
so we can't vouch for the procedures, and it may or may not be valid for all
intercoms, but it does demonstrate that a speaker swap is possible.
Also, remember that disassembling or tampering with the original intercom
units may (probably will) void the warranty. And we recommend not
tampering with the lining, padding or other parts of the helmet, which may void
the warranty and may also cause safety issues.
Another thing to remember is that speakers are just one part of a sound
system. Motorcycle intercoms are not an iPod, so the sound quality of an
intercom may never equal a decent MP3 player or other stereo system.
Adding new speakers may or may not have an effect on the sound quality, and may
also cause other problems, such as loss of volume due to an impedance mismatch.
I had been
dissatisfied with the sound quality of the speakers that
were included with the
BT Interphone intercom
One of the nice features of the BT Interphone is that the speaker and
microphone assembly are not hard-wired into the intercom unit; they connect with
a 3.5 mm jack (see photo below).
So I decided to replace the small original speakers with a higher quality
However, as many owners will
agree, without some "know-how" in electronics
and little more than a casual soldering skills, the task
of speaker swapping may seem overwhelming.
My background in electronics engineering can help me figure
things like this out though, so I decided to write this article with a
little urging from the editor.
The idea is to assist those who need
some direction and step-by-step instructions in
performing a speaker upgrade for their intercoms.
Before I begin, you must understand that this project involves
basic soldering skills (see the A Note on
De-Soldering section below) and electronics precautions,
such as understanding the issues regarding static electricity and the potential for
damaging components when you’re not properly grounded
before you start.
As for knowledge of electronics, you need not concern yourselves with
impedance matching of Interphone output to speaker. You’d be hard pressed
to find a Stereo Headphone with impedance of 8 Ohms in stores.
Original speaker and microphone headset on the BT Interphone intercom system.
Speakers or Earbuds?
Many motorcycle riders have expressed an interest in using earbuds
for their intercoms rather than speakers, and these instructions also apply to
Earbuds are basically a low impedance speakers at 18 Ohms or so for most.
Impedance is basically the "total opposition (including resistance and
reactance) that a circuit has to passing alternating current. A high
impedance circuit tends to have high voltage and low current. A low
impedance circuit tends to have relatively low voltage and high current". (Impedance
FAQ by Bruce Bartlett).
However, mounting the boom microphone on the BT Interphone intercom may be a problem when using earbuds. If you
plan on using earbuds, I suggest leaving the original
speakers in place and de-solder the speaker wires and re-solder the earbud wires
to the original speaker wires. Then you may be able to leave the mic boom
attached to the speaker or intercom unit.
I decided to re-use the original microphone boom that
came with the BT Interphone system. A hole can be
drilled in the new speaker housing to make it fit. I used an
epoxy glue to secure it in place internally.
There may be a few problems with using earbuds inside a motorcycle helmet:
first, the earbud has to be pretty small to fit; i.e., it should be flush with
the outside of the rider's ear or it may be difficult to put on the helmet or
the helmet may be uncomfortable to wear.
Also, in-ear speakers may not be legal in all states. The rider would
also have to be careful when removing the helmet to not put stress on the earbud
speaker wires. And finally, the earbuds will be hanging inside the helmet
when the helmet is removed. One solution to this may be to install male
and female jacks to disconnect the earbuds before removing the helmet, but this
adds some complexity to the project.
As for comfort level of the earbuds, I've used them before in a ride and
they're not too bad, depending on how tight the helmet fits. I do suggest
that you use an earbud without a "plastic handle" and instead use the lower
profile earbuds of the type that have the wiring coming right out of the buds.
Impedance and Ohms
The majority of the speakers or headphones found in stores will have an
impedance in the range of 16 to 32 Ohms. In modern electronics, most of
newer devices have variable control components on the output to regulate or protect
Whether the BT Interphone intercom does or not, I don't know, but the rule of
thumb is to keep the impedance as close to 8 Ohms as possible; that is, the
impedance should be as close to the 8 Ohms as possible but not imperative that
it is 8 Ohms.
I'm using a 24 Ohm speaker and so far I have no problems or issues. It
may be difficult to find 8 Ohm speakers, so again, the rule of thumb is keep the
impedance low as possible but, I wouldn't recommend anything over 24 Ohms since
I haven't tested over that value.
I would also remind the readers that their speaker selection is a personal
choice. Consider the actual size of the speaker and the speaker housing.
The speaker of choice must obviously be able to fit into the space in your
helmet where the padding around your ears will be; too big of a speaker will put
unwanted pressure on the ears and cause pain (this is where the ear buds are an
ideal option). I modified the padding on my helmet to accommodate the speakers
I've chosen for perfect fitment.
The Sony MDR-V250 headphones were used to replace the standard BT Interphone
Let's Get Started
The first thing necessary is to determine the size of the
speaker headphone that can be installed into your helmet
without making any modifications to the inserts or pads.
In my case, I’ve chosen a stereo headphone by Sony. It's called the
Sony MDR-V250V Monitor Series Headphones with In-line Volume Control
(Amazon.com link), with an
impedance rating of 24 Ohms @1KHz, pictured below.
Here are more headphones from Amazon.com.
unit is "over the ear" type and it should help in
cutting out some of the wind noise I encounter at higher
speed. Although the impedance rating is 3 times the original, I’m
willing to risk the chance of possible overload by
reduction in volume to achieve higher quality and
clarity. The choice is yours.
Once the speaker is chosen, it time to do some modification to the original
unit. First thing to mod is the speakers. Each speaker housing
is held together by one small Phillips head screw.
The speakers are held in place by the glue on the hook-and-loop material. Carefully pry the
speakers loose from the housing using a small screwdriver. Try not to cause
damage to components because you might want to reuse them again.
Sony speaker with boom mount hole drilled.
A Note on De-Soldering
Soldering and de-soldering can begin once the speakers are free from the
housing. Prior to any de-soldering, make note of the polarity of the
wiring and their colors; I find it helpful to write it down (two photos below).
To clarify the "de-soldering"; there is no need to remove the original
solder. With the soldering iron preheated to working temperature, heat the
solder until it melt and disconnect the existing wires. Care must be taken
to not overheat the wiring, solder or the PCB (printed circuit board) where the
wires are soldered to.
For more information on de-soldering, see
explanation on how to de-solder and here's a
Tutorial video that illustrates how to de-solder.
Note the extra wire on the left speaker. The green shielded wire is for the mic boom which is soldered together to the shielded ground wire (blue) of the
boom. This is important to remember when disassembling and reassembling into the
new speaker later in the steps.
I started with the right speaker since it only had 2 wires to worry about. De-solder both wires and detach the speaker.
Original BT Interphone left-side speaker with microphone boom.
Original BT Interphone right-side speaker.
Soldering The New Speakers
Going to my new Sony speakers, I started by disassembling the right housing to
gain access to the wiring and as before, noting the polarity position of each
wire. Note that this speaker actually has an imprint with + on the PCB for positive
De-solder both wires from the new speaker, solder the wires from the original
onto the new speaker with the same polarity orientation and placement, as shown
in this photo:
New right-side Sony speaker.
At this point, I connected the 3.5 mm audio connector to the BT Interphone and
paired it with my cell phone, used as a MP3 player, to test the output and make
sure it’s working before moving on.
In my case, it worked but, the volume was
little on the low side, as I expected it might be. The sound quality was excellent
compared to the original, which more than made up for the volume.
Modifying the Left Speaker for the Microphone
Now that the right speaker was wired up, I reassembled the housing and complete
the right side. We’re half way there.
I imaging this is where most is having difficulty… the left speaker with mic
boom. Well, don’t fret, it's easier than you think.
Wires from the left-side BT
Interphone headset are spliced to the new Sony speaker.
I began by de-soldering the wires from the original speaker. For the time being,
leave the green and blue shielded wires together to eliminate any possible
As before, note the polarity and the color of the wires on the new left
speaker, which is the same as the right side. Solder the wires onto the new
speaker. Both the speaker and the mic boom positives are tied together and
soldered to the speaker’s positive terminal. Now for testing…
Again, I connected the 3.5 mm connector to the BT Interphone and paired with my
cell phone and tested the speaker as before, it worked as expected.
Now that the speakers are wired-up and working, time to test the mic boom. With
the aid of my wife, we paired our helmets together and asked her to leave the
room and relocate to opposite side of the house…to make sure she hear me through
the headset and not my voice talking in the room.
New Sony speakers with original BT Interphone headset wiring.
So far, so good -- everything is working as planned. Now on to modifying the left
speaker housing so that mic boom can be mounted.
All I did was to drill a hole a bit smaller than the boom, I used a 9/64" bit
for this, in a place where I wanted the boom to come out (See the photo at the
top of the page captioned Sony speaker with boom mount hole drilled.).
Note that I made a little
mistake here -- the hole should’ve been placed where the wiring can be routed
easier into the helmet. Placing the speaker into the helmet as you would want to
mount it, then marking the placement of the boom hole is highly recommended.
Once the hole is located and drilled, the trickiest part is next. You
must de-solder the mic wires from the speaker, both positives and the negative
of the boom (those green and blue shielded wires).
After de-soldering the wires, gently push the wires through the hole drilled in
the speaker housing. It should be very snug. At this point, you may or may not
want to enlarge the hole a bit with a sharp knife. Be careful not to over
enlarge the hole, you want the boom to go through tightly about ¼" to ½" inside the
The last step is to re-solder the wires back onto the speaker. You might want to
get someone to give you a hand with this, it’s tight quarters to work in.
When the wiring is completed, get yourself some epoxy glue, mix it up as
directed and put a blob of glue onto the boom where it comes into the housing,
but not on the wiring, and making good contact with the housing. This will cure
with time, around 24 hours, and hold the boom in place. See the photo
above of the finished speakers and boom, fully functional.
New Sony speakers and modified intercom headset mounted in the helmet.
Mounting the Speakers in the Helmet
It’s now time to figure out how to mount the speakers into the helmet. After
some careful considering, I decided to demo the new headphone’s original head
piece and use what’s available.
I cut the ends off of the head piece and left it on the speakers.
Using a stick-on Velcro, I attached the mount base to the inside of my
helmet. This way, the speakers are not mounted rigidly in single position, it’ll
actually pivots to fit where it’s comfortable for me next to my ears (actually,
it turned out tighter than I expected when completed).
Depending on brand, construction and type of helmet you own, mine is Full Face
Advanced Hawk modular with dual visor, mounting methods will vary from one to
another. Careful consideration need to be made when choosing your headphones as
the final fit of the speakers inside your helmet will depend on what you decide.
In my case, as stated earlier, turned out a bit on the tight side because of the
size. On the shorter rides, it should be OK but, on the longer rides they may
At least this article will help you in the actual swapping of speakers and
the mic boom. The rest is up to you to find that "perfect" headphone for your
Good luck and happy riding.
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From "G.O." (08/10): "The procedure outlined in the article
by Tim M worked perfectly on an Interphone F4. I substituted a stereo
earphone connection for the 2 replacement speakers. The resulting clarity,
balance, and volume for music and voice communications is outstanding.
The custom IEM's I like best are Sensaphonic 2x-S (soft silicone). I ride
with custom in-ear monitors at low volume. The ride is quiet, so I can
focus on traffic and conditions rather than giving screaming truck tires
disproportionate attention. I believe the key to low-volume is sound
quality, and IEM's deliver that consistently for both music and conversation.
HJC Symax II works well for my cranium and riding style. The left ear
cushion snaps out, alleviating all cable-routing tedium. Phone/mp3/Pandora/etc.
emanate via Bluetooth from a Motorola Droid mounted on the bike's handlebars and
powered from the bike's battery.
Sadly, Interphone confirmed they don't offer an earphone jack as part of the F4,
so Tim's article was very inviting. The first stop was Radio Shack for a
stereo headphone extension cord that could be sacrificed for the female
connector pre-attached to about 10" of cable. When stripped, the usual 3
leads were available: Right, left, and common ground (unsheathed).
For headphones, there's no need to disassemble or de-solder the right speaker.
The left F4 earpiece was disassembled and de-soldered as Tim described, leaving
a red (signal) wire and a black (ground) wire as pictured in the article.
Leave the short soldered leads from the microphone untouched in their factory
I clipped the F4's right channel cable, a short female connector, about 1" from
the junction of the left channel wires and the microphone wires. When
stripped, the F4's right channel cable revealed an unsheathed ground and a white
Twist the unsheathed strands from the F4's right channel with the unsheathed
strands from the headphone cable, pre-solder them, and then attach/solder them
to the black lead to the now-detached F4 left speaker. Solder the leads
from the F4's right and left channels to the corresponding leads of the
3/8" pieces of narrow heat-shrink tubing work well on the exposed solder joints;
alternately, electrical tape will work for insulation if applied carefully.
As Tim suggests, it's good to check your work before reassembly. I found a
cheap pair of iPod headphones to plug in initially because I had no idea what
post-op volume implications might arise.
To my delight, the impedance differential between the original 8-ohm speakers
and the 27 ohm headphones was inconsequential. Volume is great when set at
50% on both the mp3 device and the F4 -- no clipping, good balance, and plenty
of detail in the sound.
Glue the headphone cable to the plastic housing, leaving the original F4 left
speaker removed. Re-glue the plastic back of the F4's headphone housing
that has the hook & loop material on it to the rest of the microphone assembly,
route the headphone and F4 command-module cable out the bottom of the helmet,
and you're off to the test ride.
Don't pass up the opportunity to solicit family approval by placing test calls
to and from the helmet with the house phone line. Total time on the
project was 1 hour. I'll be repeating this procedure in about a week on
another helmet, and will use a better camera on the next pass."
From "B.C." (7/10): "How did you deal with the loss of
volume...was the BT headset volume range sufficient or were higher volume
(output) settings required on the paired or connected devices...which again,
might lead to distortion, etc - more tradeoffs.
I would also be interested in finding out if he has encountered other system
issues, including changes in battery duty cycle, etc - all relevant impacts when
dealing with the electronics side of it all."
Tim's Reply: As to your reader's questions:
1. I really haven't noticed any volume reduction on my headset and with
the volume at 100% on BT, it's plenty loud enough for me to hear going 70+MPH.
2. For adjustment on the connected device, I don't think it's possible(?).
My Sony-Ericsson cell won't allow me to adjust the volume (more like it makes no
change/difference when I adjusting the volume on the phone).
3. For the distortion, I encountered none even with full volume.
Distortion will occur if the playback file (MP3) volume is set too high to
start. I normally edit all my music using software, such as Nero, to
remove pops/distortion/hiss and also to include "volume leveling" to set all the
files to have a same level of output sound.
4. For the performance of the BT, I haven't noticed any difference from
original in battery cycle, intercom or use of cell phone. Apparently, what
I've done to modify has had no "side effects" in my system.
Wife and I will be going on a week's vacation next week, when we get back, I'll
shoot you an update on the performance of the mod while on longer ride/trip."
From "M.G." (6/10): "I pretty much did the exact same thing
to my Bluetooth headset that goes into the Nolan N103. I used a set of
Iasus XSound2 speakers. I must say it made a huge improvement over the
stock speakers that came with the Nolan set up.
The biggest improvement, aside from sound quality, was the
amount of volume available. Now, my volume level at its lowest setting is
as loud as the stock speakers at a mid level setting. If you own the N103
BT headset, I highly recommend doing this, or finding someone with soldering
skills who can do it for you."