Cerulean RX Stereo Bluetooth Receiver
A clever addon for personal music
The tiny (2.2" wide)
Cerulean RX unit is at the top, and its sometimes relevant
partner unit, the Cerulean TX, is shown below.
of our series on Bluetooth - more articles listed on
More and more phones now
include music players in them.
But moving beyond playing the
music only through headphones, and getting the music out of
the phone and into a home audio system, or making a non-iPod
compatible with an iPod docking station/sound system, ranges
from difficult and inconvenient to plain impossible.
In theory, the iSkin Cerulean allows for
any Bluetooth A2DP supporting music player to connect wirelessly and conveniently to any
sound system. As such, it is a wonderful add-on to extend
the functionality and use you can enjoy from your phone or other
personal music player.
The device doesn't work satisfactorily, and iSkin can't/won't
fix it. DO NOT BUY.
What the iSkin Cerulean RX Does
This tiny little device is a
Bluetooth stereo audio receiver.
The Cerulean uses its
Bluetooth capability to receive an audio (ie typically stereo
music) broadcast from some sort of source - most commonly a cell
phone or MP3 player which can transmit music via Bluetooth's
After receiving the music
transmission via Bluetooth, the Cerulean has a compatible
iPod/iPhone style socket, so it can then be plugged into the
many iPod accessory speaker docks and multi-purpose
clock/radio/audio players and played over speakers. It
also has a regular audio line out so it can be connected to most
audio systems as well.
This makes it easy and
convenient to play music from your phone or other music playing
device, either through your regular home stereo or through a
player designed to work with iPod units.
More specifics are provided
below in the section on using the unit.
What you Get
iSkin's strangely named
Cerulean RX comes in a simple attractive cardboard box.
Inside is the unit itself, a USB cable, and two stereo audio cables.
One of these is a standard stereo mini headphone plug to stereo mini headphone plug
cable that you'd use for connecting from the device to any of
the audio/speaker units that have a mini headphone plug (ie 1/8"
or 3.5mm) type
input for an 'auxiliary' input, and the other connects from the
mini headphone plug, then via another short cable, to two
standard 'RCA' connectors such as are used by most home stereo
receivers and amplifiers.
There are also two User Guides (one in French, one in English) and a
product promotional brochure.
The unit has a miserly 90
day warranty which is also non-transferable, and requires you to keep your
proof of purchase. This is a very disappointing warranty
The User Guide is a short
five page pamphlet, but because the unit is very simple to use,
this is about all that is needed.
The product lists for $90 on
iSkin's website. I've not found it for less anywhere else.
Description of the Cerulean RX
The unit is very small and
lightweight. It measures 2.2" x 1.1" and is about 0.3"
thick. It weighs a negligible 0.4 oz.
It has no controls (but
doesn't really need any). There are three connectors on it
- one to connect it to an iPod dock adapter, one for a USB type
power supply, and a mini headphone jack for audio output to
other devices (if you're not using the iPod dock connection).
There is one little white light on
its front. The light flashes in different patterns to
indicate its working status.
The Cerulean RX is Bluetooth
2.0 compatible, and supports both the A2DP and AVRCP Bluetooth
The Cerulean RX has no self
contained power supply. If you are using it with an iPod
docking adapter, that's not an issue - it simply draws the power
it needs from the docking adapter.
If you are using it with a
home stereo system, you'll need to power the unit independently.
The unit comes with a USB/power cable that ends with a typical
full size USB connector, which you can plug into any USB
power source. The best type of power source in such a case
is probably going to be a plug-in 'brick' power supply that
plugs into the mains. You might already have one or two of
them lying around (they come included with many products these
days, although - alas - not the Cerulean. Otherwise, if
you need one, you
can find such things for under $10 - currently
this online store
is selling them for $7.
It is a shame that a $90
item doesn't include a moderately important component,
subjecting you to both the inconvenience and cost of having to
buy the power supply elsewhere. To put this into context,
the cost for iSkin of buying a USB power supply such as the
one being retailed for $7 above is typically less than $1.50 (if
sourced from China).
Shame on iSkin for being so penny pinching in a manner
reminiscent of the former ubiquitous but now rarely found
'batteries not included' concept.
Using the Cerulean RX
The unit can be used two
different ways :
1. Connecting to an iPod
This is amazingly simple.
Just plug the Cerulean RX into/onto the dock adapter where an
iPod would otherwise be connected, and that is all you need to
The Cerulean is now ready to
pass music from whatever player you are using through to the
audio system you have connected it to.
2. Connecting to other
This is also very simple,
but you'll have to use the connecting cables in this case.
You first plug the mini
headphone/mini headphone cable into the Cerulean, and then you
plug the other end of this cable directly into an input jack on
the sound system if it accepts mini headphone jack inputs.
If the sound player you are
connecting the Cerulean to does not accept headphone jack
inputs, the chances are 99.9% certain that it will instead
accept typical RCA jack type inputs. So take the second cable
that was supplied with the Cerulean and simply connect it to the
end of the mini headphone cable. At the other end of the
second cable are the RCA jacks - plug the red jack into the
right hand input, and the white jack into the left hand input.
You'll also need to run
power to the unit. Plug the supplied USB cable into the
Cerulean, and plug the other end of the cable into any USB power
source, such as a 'wall brick' USB power source detailed above
in the subsection on power supply. This is, unfortunately,
not an included item in the Cerulean kit, but happily if you
don't already have a spare unit, you can buy one for $10 or less
at many electronic stores or online (see above section on power
Pairing to a Bluetooth device
After you've connected the
Cerulean to the sound system that you want the music to come out
of, you need to also connect (ie 'pair') the Cerulean to the
music source - possibly a cell phone or other type of personal
Assuming the music player
device has built in Bluetooth A2DP support, this is also a
simple process. If the music player doesn't have this
feature, you'll need to get a Cerulean TX or other add-on
Bluetooth transmitter as well, although this starts moving from
the 'really easy and simple' category into something a bit more
complicated (see next
section below). In such a case, maybe it is better to just
upgrade your phone to a newer model that has the A2DP Bluetooth
profile built in.
The Bluetooth pairing code
is not printed on the unit. But it is 0000
(like so many other devices) so if you lose the instructions
(and you can download a new User Guide from
iSkin's site at any
time) it is easy enough to guess.
The Cerulean only remembers
one pairing profile, and it 'forgets' this if it loses power (a
shame that it wasn't given some permanent memory to store this
The A2DP profile definition
supports high quality audio with some error correction (for lost
packets of data). While it is true that a wired connection
between your music player and your sound system is
a better quality way of connecting the two units, the amount of
quality lost via Bluetooth is negligible.
More quality was lost when
you converted the music from its original format to the
compressed and 'lossy' digital MP3/AAC or other format it is
stored on your player with.
And unless you're feeding the output through a reference studio
quality sound system costing tens of thousands of dollars,
you'll probably not hear any appreciable additional loss of
quality caused by the Bluetooth connection between the music
player and the sound system.
In other words, for all
normal and casual purposes, there is no measurable loss in sound
quality by streaming your music via the Bluetooth wireless
The unit is a Class II
Bluetooth device, and has a theoretical range of about 10m/33 ft
- more if there is an unobstructed line of sight between the two
connected devices, less if there are walls and other obstacles.
I was able to get better
than a 50' moderately obstructed range between an iPhone 3GS and
the Cerulean RX, which is excellent. I could also have the
phone on the bottom level of my tri-level house and the player
two floors up on the top level, and that worked fine, too. When
the range gets marginal, there is no distortion to the sound, it
just starts to cut in and out entirely.
Testing with phones
I tested with three phones -
an iPhone 3GS, a T-Mobile G1 Android phone, and a Blackberry
All three phones paired up
easily with the Cerulean and sent music streams to it perfectly.
Both the Blackberry and the
G1 allowed me to control the volume from the phone as well, but
the iPhone regrettably did not. This is a serious
omission, and destroys much of the convenience of being able to
remote control a music system from one's phone. However,
being as how the other two phones do allow this, it would seem
the problem is not to do with the Cerulean but with an
incomplete implementation of the A2DP and AVRCP specifications by Apple.
Shame on Apple.
Testing with music players
I tested the Cerulean RX
with several different iPod docking music players, and also with
a regular stereo system.
Everything worked easily and
conveniently, with the Cerulean creating normal level good
quality music outputs that worked well with all the music
Incoming phone calls
When a phone call comes in,
the phone simply stops playing music through Bluetooth and
allows you to take the call normally on the phone handset.
Restart the music and
Cerulean connection when you've finished your call.
Problem with sound cutting in
Although the music was clear
and at a good level, there was a problem that was observed
with two different phones (G1 and 3GS - the Blackberry wasn't
tested) and using the Cerulean
both in a docking role and freestanding with a stereo system.
The music would cut in and
out on a semi-random basis, with brief breaks during which just
silence would be heard, then the music would return again.
This seemed to happen
whether the phone was right next to the Cerulean, or 20+ ft
distant, and because it happened with two different phones, it
seemed that the problem was not related to the phones, but
rather to the Cerulean RX.
It is an annoying problem
which appreciably detracts from the performance and pleasure
otherwise available from the unit.
Which leads to the next
point - getting some help and hopefully a fix from Cerulean to
If you have questions or
problems, you can phone iSkin's technical support on their local
(not toll free) number in Canada - (416)924-9607.
Unfortunately, their support is only available 9-5 Eastern time,
Mon-Fri. So if you're hoping to resolve an issue after
getting home from work, or over the weekend, you're completely
out of luck.
At least people on the west coast can call
before going to work, but if you live in the Eastern time zone,
it seems you'll have problems trying to solve an at-home problem
because you'll necessarily be at work not home during iSkin's
limited support hours.
I spoke to various people
who gave various responses about my problem, but no-one could or
would fix it.
I was even sent a second
unit, in case the first one was faulty, but the exact same
problem continued to occur.
My unavoidable conclusion is
that there's a problem with the design of these units. I
must recommend you NOT to buy one accordingly.
Opening Up New Content
One of the exciting
additional capabilities inherent in this unit is using it to
play more than just the plain recorded music you might have on
Maybe you also have one of
the various internet music services on your phone - for example,
last.fm or Pandora or Slacker - services which stream customized
music to you. You can play these through the
Bluetooth connection to an external music player, exactly the
same as you can play pre-recorded tracks stored on your phone.
This becomes a great way to
'pipe' internet sourced music to any type of music player without
needing for the music player itself to be connected to the
A Related Product - the
The Cerulean RX relies on
the device that has the music on it being able to transmit its
music signal via the Bluetooth A2DP profile. (In case you
need to know, A2DP stands for 'Advanced Audio Distribution
Although the A2DP profile is
becoming more common, not all phones and very few digital music
players provide this capability - and note that just because a
phone says it has Bluetooth, that does not mean it has the
stereo music streaming capability. Most Bluetooth equipped
phones simply allow for you to connect a headset to the phone,
not for any of the various other Bluetooth connectivity
So, what to do if you have a
non-A2DP equipped music playing device that you'd love to
conveniently connect to your stereo or to an iPod type speaker
dock or external music player?
In theory, this is an easy to use
device that makes it much more easy and convenient to feed music
- either already stored on your phone/personal music player, or
sent live via the internet to your phone - out of your
phone/music player and into a regular music player so you can
fill a room with music rather than be forced to listen to it
The device is small and
simple, but the problem with the music being interrupted with
brief silences detracts from its usefulness. Hopefully
this can be resolved.
BUT. The device doesn't work, and iSkin can't/won't fix
it. DO NOT BUY.
If so, please donate to keep the website free and fund the addition of more articles like this. Any help is most appreciated - simply click below to securely send a contribution through a credit card and Paypal.
25 Sep 2009, last update
28 Nov 2012
You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.