Sharp 4 pole earphones
When I am talking about ‘phones or portable audio devices, mainly minidisc, I will occasionally mention the phrase 4-pole ‘phones. It isn’t something very important but I do want to take this chance to clarify the phrase and show you the available 4-pole earphones.
notice the two black bands which is 3-pole…
notice the three black bands which is 4-pole…
4-pole ‘phones are earphones with a split ground. According to an article written by Peter Rice in 2002, “Differential (push-pull) operation of phones and speakers, where the + and - leads of each ear phone are driven in anti-phase to get 4x the output power from a given battery voltage. This, of course, precludes a common lead for the two ear pieces, hence 4 leads to the phones“. So the use of 4-pole in portable audio devices for increasing the output power means less drain on the cell so playback hours are extended.
Using 3-pole ‘phones plugged directly into a 4-pole outlet has never presented any problem but using 4-pole ‘phones plugged into a 3-pole outlet results in music only coming through the left earpiece.
The use of 4-pole was widespread in the portable minidisc market. Sharp, Victor, and Kenwood used 4-pole with their units beginning in 2002. Panasonic may have also but their proprietary 2.5mm headphone plug rather than the standard 3.5mm plug prevents me from plugging my ‘phones in to verify. The Victor and Kenwood, of which Kennys were rebadged Sharp units, were 4-pole at the jack on the unit but their remote controls acted as converters so the user could utilize 3-pole ‘phones. The Sharp units maintained the 4-pole connection through the remote controls. Having 4-pole available from the remote control opened up a niche market for Sharp to create ‘phones that were 4-pole and market them as the best ‘phone for listening to their devices.
Here is a list of the available 4-pole earphones from Sharp…
earbuds
HP-SM30-S (silver) retail price in Japan; 2,200 円
SM-30 stats:
Drive diameter, 16mm
Impedance, 32 ohms
Max. allowed output, 10mW
Sensitivity, 95dB/mW
Frequency response, 20~20,000Hz
HP-SS30-S (silver) retail price in Japan; 2,200 円.
HP-SS30-S stats:
Drive diameter, 14.5mm
Impedance, 32 ohms
Max. allowed output, 10mW
Sensitivity, 97dB/mW
Frequency response, 20~20,000Hz
HP-SS30 (left) next to HP-SM30 (right)
user experience: These are stock buds that are available at the retail level. They get the job done but they don’t provide a wide soundstage nor depth.
clip-on
HP-MD1-S (silver) retail price in Japan; 2,900円
HP-MD2-A (blue) retail price in Japan; 2,900円
HP-MD2-P (pink) retail price in Japan; 2,900円
all three colors next to each other…
HP-MD1 and MP-MD2 stats:
Drive diameter, 30mm
Impedance, 32 ohms
Max. allowed output, 20 mW
Sensitivity, 105dB/mW
Frequency response, 20~20,000Hz
user experience: The 1’s & 2’s sound better than the buds because they have larger drivers. These give a wider soundstage, more depth, and the stereo separation sounds better through these. The hangers are plastic and are not thick on the edge that makes contact with the skin surrounding the ear. Less surface tension results in a clip-on that slips off too easy, at least for me.
HP-MD5-S (silver) retail price in Japan, 5000 yen.
MD-5 stats:
Drive diameter, 30mm
Impedance, 32 ohms
Max. allowed output, 50mW
Sensitivity, 102dB/mW
Frequency response, 20~20,000Hz
user experience: This set is more expensive than the 1’s & 2’s but I think it is for the housing quality rather than the sound quality. These require you to turn up the volume to a higher level to match the sound level of the 1’s and 2’s. The sound quality is a little bit better but not enough to prompt me to buy a backup set for when these finally give up the ghost. Regarding fit, the rounded rubber-coated metal hangers do hold the ‘phones in place better than the plastic hangers of the 1’s & 2’s.
sealed earbuds
HP-MD33-S (silver) retail price in Japan, 3500 yen.
HP-MD33 stats:
Drive diameter, 9mm
Impedance, 32ohms
Max. allowed output, 20mW
Sensitivity, 120dB/mW
Frequency response, 20~20,000Hz
user experience: A very clean and detailed sound; I think these are the best sounding of the available 4 pole ‘phones. I don’t ever use these when I’m out-and-about because I can’t get them to stay in. The vibrations from my body motion break the seal and then they fall out. I think this is due to the shape of my ears as I know several people who wear these about their day and they have no problems with the seal breaking.
hanger
HP-MD90-S (silver) retail price in Japan, 12,500 yen.
HP-MD90 stats
Drive diameter, 16mm
Impedance, 32ohms
Max. allowed output, 20mW
Sensitivity, 95dB/mW
Frequency response, 20~20,000Hz
user experience: These are strong and detailed and give a better sound than any of the clip-ons even though they have larger drivers. They are lightweight, they sound good, and the ear hangers keep the buds in place. I think they are overpriced. For less money, you can get better sounding earbuds such as the Sony e888’s or Audio Technica ath-cm700’s but neither are available in hanger style.
All 4-pole ‘phones come with a 3-pole to 4-pole converter chord for use on audio devices that aren’t 4-pole. Remember, without that converter chord you’ll only hear sound out of the left channel when plugged into a 3-pole jack.
 |
US $1.99 End Date: Monday Jul-14-2008 1:59:21 PDT Buy It Now for only: US $1.99 Buy it now | Add to watch list |
Original sharp 902 903 cell phone remote with headphone
 |
US $9.99 End Date: Friday Jul-11-2008 3:40:44 PDT Buy It Now for only: US $9.99 Buy it now | Add to watch list |
Original sharp 902 903 cell phone remote with headphone
 |
US $9.99 End Date: Friday Jul-11-2008 3:40:42 PDT Buy It Now for only: US $9.99 Buy it now | Add to watch list |
OEM Sharp Sidekick LX Stereo headset / headphones 3.5mm
 |
US $4.45 End Date: Sunday Jul-06-2008 16:32:39 PDT Buy It Now for only: US $4.45 Buy it now | Add to watch list |
Sharp DRW-V2 Digital DJ AM/FM Stereo Radio w/ Headphone
 |
US $9.99 End Date: Thursday Jul-10-2008 13:42:44 PDT Buy It Now for only: US $9.99 Buy it now | Add to watch list |
Ipod diamond bling heart sharp earphone headphone
 |
US $12.00 (0 Bid) End Date: Sunday Jul-06-2008 10:42:54 PDT Buy It Now for only: US $12.00 Bid now | Buy it now | Add to watch list |
Original sharp 902 903 cell phone remote with headphone
 |
US $9.99 End Date: Tuesday Jul-08-2008 22:18:18 PDT Buy It Now for only: US $9.99 Buy it now | Add to watch list |
Original sharp 902 903 cell phone remote with headphone
 |
US $9.99 End Date: Sunday Jul-06-2008 18:10:25 PDT Buy It Now for only: US $9.99 Buy it now | Add to watch list |
Sharp 3.5mm Headphone&Adapter for 902 903 V902 V903
 |
US $3.99 End Date: Monday Jul-07-2008 4:13:26 PDT Buy It Now for only: US $3.99 Buy it now | Add to watch list |