Etymotic Research ER-4P MicroPro and ER-6 Isolator Earphones Review


Like many groups of electronics enthusiasts,  audiophiles can be very
opinionated about their hobby. When asking such a person to give you advice on
the best audio equipment, you may get more information than you bargained for if
you aren’t an audiophile yourself. Me, I’m a music lover. But, I do not pretend
to be a music aficionado. Basically, I can differentiate between good sound
quality and great sound quality. But, I’m not so sure that I can hear a big
difference between a song file encoded at 192Kpbs and the same song encoded at a
higher quality bit rate such as 320Kpbs. I’m telling you this so that you’ll
know where I’m coming from when I talk about the latest products to come across
my desk: Etymotic Research’s ER-4P and
ER-6 earphones.

These earphones are not your typical Wal-Mart specials. They are earphones
for serious music lovers who have quite a lot of extra jingle in their pockets.
They are also like standard ear buds, these earphones actually fit into your ear
canals. Let’s take a look…

ER-4P MicroPro Earphones

There are 3 different ER-4 models: B, S and P. The B model is optimized for
binaural recordings. The S model is stereo (preferred by musicians), and the P
model is the same as the S model, but with enhanced bass response and higher

The word Etymotic means "true-to-the-ear". That is a very accurate
description of the sound quality that these earphones produce. The ER-4 line are
for people that demand and need the best. Although they work perfectly fine with
CD players, radios and MP3 players, they are really better suited for musicians,
recording engineers and audiophiles. I say this mainly because the ER-4’s have a
price tag of $330. Ouchy!

I could tell that these earphones were something special from the moment I
opened the nicely sized plastic storage box. Arranged neatly were:

5′ cord with 3.5 mm stereo phone plug
1/4" stereo phone adapter plug
6 white flanged ear tips
10 black (13mm) foam ear tips
Filter-changing tool with 4 filters
Instruction booklet
Shirt clip
Carrying pouch

Taking out the ER-4P’s, I was immediately struck by their robust
construction. Most earphones that you buy these days have thin wimpy cables that
feel very fragile. Not so with these. There are actually two twisted wires
coming out of each earphone. The main cable is also twisted and sheathed in
additional plastic, to make it thick and strong. I think it would take a lot of
abuse to break the wires in these cables.

If you aren’t scared away by the price tag, I’ll have to tell you that these
earphones produce the best sound quality that I have ever heard. Listening to
music through the ER-4P’s is a very enjoyable experience. Music is bright but
not too bright, and the bass response is surprisingly thumpy. The P in the model number stands for Power. These earphones can be used with low powered audio devices without needing an amplifier. I actually found that I could turn the sound down a fair amount on my iPod while using these earphones. How do they
produce such great sound? Here are the tech specs:

Frequency response re nominal: 20 Hz to 16 kHz +/- 4 dB; 50 Hz to10 kHz +/- 2
1 kHz sensitivity: 109 dB SPL for .2 Volt Input; 107 dB SPL at 1mW
Impedance: 27 Ohms nominal
Maximum output: 122 dB SPL
Maximum safe continuous input: .75 V RMS
Acoustic polarity: + Electric = + Acoustic
Transducer Type: Dynamic

If you’re like me, those specs really don’t mean much. All I know, is how
they sound when they are in my ears. That’s the main feature of the Etymotic
earphones, they fit inside your ears. By doing this, they virtually eliminate
most external background noise (20-25 dB isolation), allowing you to get the
best sound possible.

The isolation factor makes these earphones great for use during flights,
while at the dentist, at a noisy sporting event, etc. I tried them out during a
4hr flight from Indy to Las Vegas and found that they blocked out most of the
engine noise of the plane. Wearing them does take some getting used to though. I
found them to be somewhat uncomfortable after wearing them for a long period of
time (longer than 60mins). Although the tips are made of soft plastic, not
everyone will be able to handle the sensation of placing them deep into your

A cool feature of the ER-4’s is the fact that the tips are removable. Besides
coming with 2 extra sets of plastic ear tips, 10 black medium sized foam ear
tips are also included. These are soft spongy form fitting tips that are similar
to the earplugs that are used in loud working environments, or for sleeping. If
you don’t find the plastic or foam tips to be comfortable, you can even order
specially molded inserts for your ears.

These earphones also have replaceable filters. The filters can become clogged
with earwax after time (can you say eew?!). Several filters and a special tool
to facilitate removal is included.

I think these earphones are the top of the line as far as construction and
sound quality. If money is no object, and you don’t mind the in-ear style, the
ER-4Ps could be an audiophile’s dream come true.

Price: $330.00

Fantastic sound
Replaceable ear tips and filters
Solid construction

In ear style may be uncomfortable for some


ER-6 Isolator Earphones

If you can’t shell out the big bucks for the ER-4Ps, the Etymotic ER-6
earphones are priced more in line with medium end consumers. Like the ER-4s,
these are also in-ear style earphones. I found them to be even more isolating
than the ER-4s though.

Instead of 3 flanges on the ear tips, these only have 2. For me, this made
them feel more comfortable in my ears for a longer period of time.

The ear tips and filters on this model are also easily removable. A special
filter removal tool, 1 extra set of filters and a set of foam tips are included.

The sound quality of the ER-6s are great. Not quite as ‘realistic’ as the
ER-4Ps, but still very good. Like the ER-4s, they are great for flights and
other noisy situations. I tried to use both of these earphones at work, and
home, but the felt too cut off from my environment. So, for me, I would probably
only these isolator type earphones for flights.

Construction of these earphones is more in line with typical ear buds.

The ER-6s are an affordable set of earphones for the music enthusiastic that
desires total seclusion from noise and other distractions. I’m definitely
keeping this set in my travel gear bag.


Price: $139.00

Great sound / isolation
Replaceable ear tips and filters

In ear style may be uncomfortable for some



Product Information

Manufacturer:Etymotic Research
  • Great sound / isolation
  • Comfortable
  • Replaceable ear tips and filters
  • In ear style may be uncomfortable for some
Posted in: Audio, Video, TV
{ 14 comments… add one }
  • Julie January 15, 2004, 3:48 am

    Post your comments here on the Etymotic Research ER-4P and ER-6 Earphone Review.

    Just click the POST REPLY button on this page.

  • January 15, 2004, 4:26 am

    These are by far the best earphones I have ever had, and the
    smallest and easiest to carry. On airplanes, the isolation they
    provide is remarkable, you can actually listen to music or
    movies on a portable DVD machine and not hear any engine
    noise. A drawback is that you better be careful using them on
    the street, as you will not hear a car or bike bearing down on you
    either. I use the 4S model, the 4P for portable is meant to
    be powered by weaker output portable devices, but I have had
    no problem with the 4S model in this regard.

    You might note that Etymotics makes a really cheap earplug with
    the same design as these headphones. They take sound
    levels down 15 dB evenly across the spectrum, which means that
    at a loud party you hear the person shouting over the music
    and the music at about 1/4 the volume, but no loss (nor gain)
    in intelligibility. I love the things, they run maybe $10-15. Look
    a bit weird in your ears, but save your hearing.


  • fitzsimmons January 15, 2004, 5:06 am

    Julie, enjoyed your review. Just a note about the ER-4S: you need something fairly powerful to drive them, so lots of people use portable audio amps. These can improve sound noticably but can make your gadget bag somewhat cramped. Still, if anyone cares about that “true audiophile experience” :cool:, you can check some out at:

  • Julie January 15, 2004, 1:01 pm


    You’re right, that’s where the P differs from the S, it does not require an amplifier. I noticed that I could actually turn the sound down a little when using the ER-4Ps, over the ER-6s.

  • One of One January 15, 2004, 2:35 pm

    It’s not surprising, but a bit fascinating to me how different people’s ears hear the same things. I went out and bought the ER-4P’s from, but after listening to them for awhile, I didn’t like the sound at all. I also researched on different sites including to see what others thought, and although there are many people who like the 4P’s, there are just as many who don’t. They’re great for classical music and music with a lot of delicate high end, but if you want it all, including a fuller sound and real full bass, the 4P’s just won’t cut it.

    So I returned the 4P’s in exchange for one of Headroom’s portable TOTAL Bithead amps (that according to them, won’t be shipping until the beginning of February this year). It not only will plug into an Ipod, but can also be used with a laptop as well via USB. An amp will make the sound even better though any phones, and in addition, I will be saving up for some Ultimate Ears UE-10’s. These are VERY expensive (around $950), but they’re as high end as you can get in an ear monitor (they have an extensive clientele list of top level bands and musicians), have triple drivers for very full bass, and also include custom ear molds as well to fit your ears perfectly and comfortably. And just as an added bonus, you can choose the color of both the cord and ear molds. It requires you to go visit an Audiologist to get ear impressions that you later send to UE so that they can make the molds from that, but I couldn’t imagine anything more comfortable or rich in sound than these. I figure, if they’re good enough for all of their clientele (who could afford anything), then I have little doubt that they’re good enough for me. I also am very sensitive to sound, and a musician myself, so it matters to me, will serve me in both capacities (leisurely and musically) and is worth it to me to invest this much, even if it seems crazy to others (which, of course, is irrelevant as long as it serves my needs and wants).

    But at any rate, I figure with this amp and these earbuds, I’ll not only be comfortable, but will have the best sound imaginable. Expensive, but to me, worth it.

  • Julie January 15, 2004, 4:43 pm

    One of One:

    It is interesting that we all hear things differently. My favorite earphones are my B&O earbuds. Their sound quality is great, and for me, they are the most comfortable ones I have found so far.

    I’m curious to know how many people enjoy using isolating earphones in places other than airplanes? I really don’t like the feeling that they give me when I try wear them at work. I guess I’m afraid I’ll ‘miss’ something that my co-workers might be doing or saying.

  • One of One January 15, 2004, 5:20 pm

    Originally posted by Julie
    [B]One of One:

    It is interesting that we all hear things differently. My favorite earphones are my B&O earbuds. Their sound quality is great, and for me, they are the most comfortable ones I have found so far.

    I’m curious to know how many people enjoy using isolating earphones in places other than airplanes? I really don’t like the feeling that they give me when I try wear them at work. I guess I’m afraid I’ll ‘miss’ something that my co-workers might be doing or saying. [/B]

    For myself, I like the isolation factor just because it gives me some peace and quiet without having to listen to people yammering on about things I don’t care about, crying babies, screaming kids, loud cell phone conversations, and whatever else I don’t want to listen to. I’d wear these on an airplane, at a bookstore, at a coffee shop, on public transportation, at home, in a parked car (not while I was driving, though!), or anywhere else I could relax. If I was at a job, however, I wouldn’t wear these. I probably wouldn’t wear anything just because I’d need (and want) to be at full alert with everything going on around me.

    But for everywhere else, the isolation is the only way to go. The superb noise cancellation along with superb sound reproduction is nothing short of candy for the ears and for my well-being.

  • fitzsimmons January 15, 2004, 5:25 pm

    I’m a fan of isolating earphones — I don’t think there is better sound bang for the buck — for their total sense of immersion. As someone said above, don’t wear them in traffic or at home if you need to hear the phone, doorbell, spouse ;), etc…

    A very important advantage is that they are far less damaging to your ears than traditional headphones because you can turn the volume down so much and still hear perfectly. You don’t need them to drown out background noise because with your ear canal plugged, you can’t hear it anymore. (Unfortunately, you don’t get this same effect with noise cancellation headphones, e.g., Bose, and extended headphone wearing really does damage your hearing.) So, for this reason alone, I think they are worth consideration, and since the sound is superb, it’s an easy decision for me.

  • One of One January 15, 2004, 5:28 pm

    Oh, and by the way, Ultimate Ears does make their UE-5 Ambient, which is a great ear monitor that offers adjustable isolation. You can adjust it for maximum isolation, clear down to little isolation (you can refer to their website for actual specs) so that you can hear the outside world while listening to whatever it is you’re listening to. Granted, the sound quality decreases as isolation decreases, so in that state, it wouldn’t have the same level of fidelity as say, the UE-10’s (due to their complete isolation properties among other things), but it is a great design factor, nonetheless. But that isn’t to say that the UE-5’s don’t have great sound quality in general. You may want to check them out.

  • One of One January 15, 2004, 10:15 pm

    The president from Ultimate Ears said that their website is undergoing construction and that they’d have the newly revised site up anyday now, along with the UE-10’s.

  • nuxi January 15, 2004, 11:01 pm

    Interestingly enough, Apple just released a set of in-ear phones. Though not in the same class as the Etymotics, they’re much cheaper ($39) and are alleged to provide better sound and isolation than the stock ipod earbuds.

    Any chance of a review of those new phones?

  • spunkyfunky January 16, 2004, 2:29 am

    These sony’s have satisfied me for over 2 years and they are much cheaper than many of the referenced products in the followup posts to the review.

  • Sneezer January 22, 2004, 6:32 pm

    Check out He has some pretty nifty portable amps, very small and efficient. He also has a tip to modify the Koss “The Plug” earbud to get better isolation and improve sound. Not bad if you need to stay on the cheap.

    The only times I use headphones these days is on airplanes. For that I have a set of Kenwood noise canceling headphones, similar to the Bose but far cheaper. Does an excellent job of eliminating the drone of air travel for me.

  • ericgold August 11, 2004, 12:57 pm

    For an additional take on some of the other isoloating earphones around, take a look at Joi has gone through all the Shure headsets, and now swears by Sensaphonics (at around $900).

    I have chosen to go with Shure – and have maxed out with spending $150 on the E3c’s (I also have E2c’s – not nearly as comfortable as the E3c’s – if you have smaller ears). Shure seems to have beaten down the “microphonics” problems pretty well – microphonics is the noise that travels through the wire — usually as a result of the wire rubbing against clothing — and results in a fairly distinctive rustling sound. It is most annoying when using the headset while doing any vigorous excercise. A number of other users have reported microphonics to be significantly worse in the Ety’s.

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