Shure's Music Phone Adapter is the only one with a microphone and a switch to pause and restart the music. I encounter a need for the switch a lot. I play my iPhone through my car stereo via a cassette adapter, which I trimmed with clippers so it will fit in the iPhone's recessed jack. When I unplug it to leave the car, the iPhone pauses the music, which is good. When I plug it back in, the music stays pasused until I turn it on and press the play button. I would much rather have a pause/play button as is on the earbuds that ship with the iPhone. The Shure Music Phone Adapter has this button. The other's don't.

Your method of a/b'ing with and without the adapter is fatally flawed. This type of test generates the conclusion "does affect sound quality, but only slightly" so often it has become an audio cliche.

You owe it to your readers and the subject of your review to conduct a more rigorous or honest evaluation.

Either commit to a more reliable test, or do not claim to hear the predictable "slight difference" that could be the result of numerous variables other than the adapter.

Does that Vibe Duo headphones include the mic SWITCH like the standard iPhone ones...you know, click to answer? At $101, they're steep, but sound worth it if they have full functionality

iMac Pr0n: Yes, the Shure adapter is the only one with any sort of inline control.

Dave: Our review of the Vibe Duo will be posted very soon.

Audio Engineer: Any test of sound quality is inherently subjective, and I didn't claim this test was perfect. However, as with any experiment, the best way to compare the impact of something is to control all other variables. By testing the Headphone Adapter with the same exact headphones (ones good enough to at least resolve some differences), with the same exact music files (again, of high enough quality to reveal some differences), and on the same hardware, any differences in sound quality -- better or worse -- are due to the adapter. What are these "other numerous variables" that might be causing differences?

(Note that I didn't attempt to quantify the differences, nor did I say which was better or worse, nor did I make any claims as to why these differences exist -- it could have been something as simple as a tiny bit of added resistance. I just noted that, as someone with good ears and a good deal of experience testing audio gear, I could hear a slight difference.)

Please suggest a "more rigorous or honest" evaluation method that's appropriate for a consumer-level publication.

Is someone there going to spring for an Aliph Jawbone and test it out with the iPhone? Surely you can sneak that by your accounting folks there somehow?

Michael:

Yep, we've got one, and I'll be doing a review of it shortly.

I haven't yet seen an official response from Apple of why they had to make the headphone jack recessed. It would be good if Macworld or other high level news gatherer hit up Apple for an answer to this.

I ended up doing minor surgery on my ER6i headphone jack so it successfully fits into the iPhone. I had the Belkin adapter and returned it. I was not fond of the idea of an additional adapter that sticks out of the phone like an antenna.

@KeithC: Looking at the design of the phone, it's pretty clear that the headphone jack is recessed so that Apple could keep the iPhone's back all curvy and pretty.

But the next time I'm talking to Apple I will ask.

Dan,

Thanks for allowing my message to be posted! I was afraid because it was critical it wouldn’t make the cut!

Since no one can listen to two discrete things at the same time, there is no perfect a/b test, although there are a number of next-best things that audio professionals attempt by minimizing variables.

I take it you listened to music with and without the adapter. In this case, you are comparing real-time music with your memory of what the music sounded like the other way. However, enough time has elapsed that your “musical memory” is not a strong enough reference to register the “slight difference” you express.

Studies show that if you do a test like this and tell a group of evaluators that something like the Belkin adapter is an enhancement device that will subtly improve their listening experience and then ask them to listen to the same excerpt with and without it, they will tend to say they hear, as you did, a “slight difference” – a slight improvement. Use the very same adapter, a different group of people, and explain that it is an adapter with the potential to subtly degrade the sound, and they will tend to report that they again have heard a “slight difference” – not surprisingly, a slight degradation.

A better test would minimize the variables of musical memory and psychological mindset. One way to accomplish this is to have two similar devices that differ only in the product you are attempting to evaluate (e.g. an adapter, a converter, whatever). You put them through a high quality switch that feeds a common monitoring system (e.g. headphones, speakers, whatever). While the music is playing, you switch from one to the other, and without the time break of stopping the music and changing the setup (e.g. w/o putting in or taking out the adapter). The variable of musical memory is minimized because there is less time between the comparison. Have someone else work the switch and keep secret which sample includes the adapter and which one does not (i.e. a blind test) and you correct for psychological mindset.

However, this method opens the door to another variable which is often far greater than the difference in products under review, and is typically overlooked: the musical content itself. Immediately switching from system a to system b does not traverse identical musical content. The music continues to play and is not the same; measures 1 through 8 do not sound like measures 9 through 16. All sorts of musical and production variables – different notes, chords, sounds, arrangements, performances, etc. – conspire to influence an opinion. A listener might conclude a “slight difference” in equipment when the difference is in the underlying musical material itself. Alternatively, if you “rewind” to the beginning as you switch from system a to b in order to evaluate identical musical material, you invoke musical memory and find yourself comparing real time music with an imperfect memory of it.

So, as you ask, what is a “’more rigorous or honest’ evaluation method that's appropriate for a consumer-level publication.”

I would do this (and it’s not perfect, but what is?): I would have two identical systems with the only difference that one has the adapter and one does not. I would have the same music on both. I would feed the output of the devices (iPhone w/o adapter, iPhone w/ adapter) to an a/b switch and then to a monitoring system – high quality speakers of headphones. Yes, the switch could also degrade the signal but it’s a constant in both cases and therefore cancels itself out. Then, in order to ensure a psychologically-unmotivated comparison, I’d compare blind by having someone else start the music on both players simultaneously and without telling me which is which, switch back and forth and have me record my response.

Furthermore, it is well-established that volume levels influence frequency response (Fletcher-Munson curve) as well as the buying habits of adolescent males. This is why stereo salesman turn up the volume on the system they wish to sell: it sounds better as well as louder. The a/b test would have to be calibrated for volume, and repeated from scratch a few times just to make sure that volume hadn’t polluted the evaluation.

I’d also have other trusted listeners in the room to record their opinions as well. I find that when true audio differences exist, they can be heard by more than one person. Alternatively if only a subset hears the difference but hears it consistently, you get a sense of how small the difference truly is. Doing it this way is also, you know, kind of fun.

Otherwise, if I had only made an uncontrolled comparison, the influence of the variables eclipses the validity of a “slight difference” and I wouldn’t report it. Indeed, so great is the temptation of audio reviewers to detect a “slight difference,” with all its overtones of competence and expertise, under these circumstances with these variables, I would disclose the limits of my listening system, my species and myself before I'd report a "slight difference." I’m not suggesting in any way that you are lying, only that it is potentially misleading in a non-blind uncontrolled comparison.

If you had access to measuring equipment, and could confirm slight differences with measurements, that would be a different story. However, if I am being honest, I would also say that the differences that can be measured by a single adapter are miniscule. I mean miniscule miniscule.

I do not believe the degradation introduced by this kind of adapter on sound from a device like the iPhone can be heard, however golden the ears. Indeed, in high end studios, these types of adapters (more sturdy versions but same electrical characteristics) are placed in the signal chain all the time without any demonstrable degradation. Furthermore, as good as the iPhone sounds (and I think it sounds great), it is not sufficiently high fidelity to push the limits of an adapter; there are far more treacherous obstacles to fidelity within its housing. Even an audio signal from high fidelity equipment, costing tens of thousands of dollars, would have a difficult time getting discernibly degraded by the Belkin adapter, particularly an adapter in new condition. As small as it is, electrons are smaller, and the resistance is inconsequential given its length. If Belkin had made the adapter 50 feet long, and you allowed it to oxidize at your beachfront bungalo, it might be another story (although line level signal is fairly resilient).

So what is the problem with the adapter, if any?

As I see it, it’s precarious. Sticking something out of a jack like that increases the likelihood that the jack will be jimmied and damaged. Minijacks tend to be weak links (the one exception I know is the minijack in Sony’s comparitively expensive PCM-D1). Therefore, the potential wear and tear from the adapter on the jack over time might cause the signal to annoyingly cut in and out. Incidentally, the principal reason audio pros hate minijacks is not because of signal degradation, but because the physical connection itself is precarious and tends to go bad.

As I’m sure you know, a number of users are chiseling off excess plastic on existing headphones that are otherwise too fat. Obviously, no one should chisel off protective plastic to the extent that it exposes wires, but if a little can be removed without harm, that may be a better solution than an adapter. Or use an adapter and be careful not to bang into it. But I wouldn’t avoid an adapter because it purportedly causes a “slight difference” in sound quality, and I wouldn’t report that based on an uncontrolled comparison. As always, IMHO.

KeithC: I have heard that the addition of the mic band (in addition to the usual stereo output) was a contributing factor in Apple's decision to recess the audio jack. But I have also heard that it was purely aesthetic which, if true, is a shame!

Sound Engineer: All of your points are good. In an ideal world, that would be a way to test. (Although there are often variances between two "identical" devices, so even testing using two similar sources isn't a guarantee of a control.) And many of the issues you mentioned are precisely why I didn't make any evaluative claims; I said only that I heard a (slight) difference.

Part of the problem here -- and why I can't set up a test like the one you propose -- is that precisely because the iPhone's headphone jack requires an adapter, there's no truly controlled way to test audio with and without that adapter. See the Catch 22? So I did the best I could, which was to switch back and forth using the best headphones I currently have that can be used with and without the adapter.

Yes, "memory" effect is a concern in a test like this, but the more times you switch -- and the more times that switch is random, so you don't know which you're listening to at any particular time (I had someone else switch for me for part of my test) -- the less effect memory has. (And when you don't know which is which, it removes the bias you describe where people project their expectations.)

I'm also familiar with the Fletcher-Munson Curve. In fact, I took into account that perhaps part -- or even all -- of the difference I was hearing was due to slightly different volume levels caused by the adapter itself. That's one reason I didn't evaluate the difference.

As for whether or not this Belkin adapter could affect the signal enough for me to hear it, we'll just have to agree to disagree on that point.

"I wouldn’t avoid an adapter because it purportedly causes a 'slight difference' in sound quality"

And, to be fair, I didn't say anyone should. In fact, I said just the opposite.

The funny thing is that if I hadn't reported on my personal listening experiences, someone would have said, "But you didn't address the most important issue -- does it affect the sound?" And I would have been engaging in this same discussion after I posted my personal experiences here in the comments ;-)

Jason:

"Looking at the design of the phone, it's pretty clear that the headphone jack is recessed so that Apple could keep the iPhone's back all curvy and pretty."

I agree, but it certainly would have been possible for Apple to make the opening a millimeter or two wider without disturbing the curvy aesthetic. The fact that the jack is recessed isn't the problem. The narrow diameter of the opening leading to the jack is the culprit.

All these iPhone headphone adapters, yet I want to go into a store and just buy one. I'm inclined to get this belkin one because it's simple and clean, but I also have Shure e2s so their MPA would be great, but as far as I can tell, Belkin is only selling their adapter online with 1-2weeks shipping and the MPA hasn't been actually released yet.

@David C.: I got one of the Belkin adapters at an Apple Store, so they're out there.

@Corman: I guess Apple's designers would argue that making the opening wider would harm the curviness and prettiness of it. I don't disagree with you, though. It sure would've been better if the iPhone fit all plugs.

On nearly every portable-electronic device I've had over the past 30 years, the thing that broke (or broke first) was the headphone jack. There's a lot of side-to-side stress on these jacks due to the leverage of connected plugs.

This is pure speculation, but I wouldn't be surprised if at least part of the reason Apple recessed the jack was to reduce strain on it -- on the iPhone, a good deal of plug-stress is borne by the metal casing around the jack instead of by the jack itself.

That's not to say I like -- at all -- having to use an adapter to use my headphones...

I posted a short "How-to snip your headphone jack to work w/ your iPhone". I wanted to use my Bose QuietComfort 2's. I got a comment that the same trick works with QC 3's as well. Pics included...

http://www.lessonportal.com/wordpress/?p=15

I hope this helps someone out there!

I have an aliph Jawbone and it works great with my iPhone. Callers tell me the noise reduction is startlingly good. I bought it to use with my previous phone a blackberry 7130e, and It works better with the iPhone. It has disconnected and needed to be paired again, but otherwise the iPhone-Jawbone duo is the best I have ever used.

I'm pretty sure the Belkin adapter damaged my iPhone's headphone jack enough that the adapter doesn't work properly anymore. The rigidity of the adapter combine with the less than totally snug fit in the headphone jack may be to blame.

When I used it with my Shure headphones at the gym, it wouldn't fit in the little storage compartment of the treadmill I use without bending it. Unfortunately, I think this (because the adapter doesn't seat as snugly as the Apple headphones) may have placed a little undue pressure on the headphone jack's contacts cause ever so slight movement of the contact inward such that the Belkin no longer makes reliable contact with the jack's contacts. The result is disconnects leading to sporadic pausing of music, as well as loud pops and crackles as the jack iPhone is moved.

Aside from the absurd look of the setup with the huge adapter plugged in, I think the potential damage to a $600 phone caused by a $10 adapter warrant staying away from the Belkin adapter. Fortunately, the iPhone's headphones still work, but those are nowhere near as good as the Shure's -- especially when exercising.

the headphone jack on the iphone may indeed be recessed to protect the jack and phone. My son's iPod was totaled when a friend tripped over his headphone cord ripping the plug out of the jack. Apple informed us that the jack on the ipod is built into the motherboard, to repair it meant replacing the motherboard. It was cheaper to buy a new ipod. I haven't used the Belkin and can't say whether its' design helps or exacerbates potential problems with the jack. I have pre-ordered the Shure adaptor to use w/ my E3c's.

Not being able to use my Ultimate Ears Super Fi-5 pro's was one of the reasons I did'nt want to get the iphone. But the second week on the shelves I got one anyway. For the love of my Ultimate Ears I had to use them so I sanded the bezel down just enough to fit snugly into the recess. I sanded it because I don't trust chopping or cutting on the plug of $200 headphones because once you cut too much it's gone. So for such a small increment to be leveled the medium sandpaper (a very small piece in fact) made me a very happy camper. Although I do miss the mic. and control that is offered with the iphone headgear I justify my sacrifice by knowing that I listen to more music and videos than I spend time on the phone.

Also I forgot to mention that I fully agree with Sound Engineer on his point about things sticking out of your portable unit being a targeted weakpoint. I do not use any straight jacks on portable units because they are accidents waiting to happen, meaning that the headphone connection on your expensive gadget will be the first thing to go. As much as I like the sound quality of V-Moda products the fact remains that all of thier headphone plugs are straight. A straight plug in the pocket or on the belt will be compromised sooner than later, it's happened to me numerous times. So if I wasn't a bit of a craftsman and modified my phones I would easily spend the extra bucks for the Shure adapter with the angled plug and the controls. Meanwhile I've been enjoying my iphone very much and have come to the conclusion that those who don't like them are the ones that don't own one. It's about time that my carrier Cingular/the new ATT came out with a slamming unit to put the other carriers on notice. Blackberry is cool but expensive, T-Moble's Sidekick is cool too but kinda large, Prada phone is european only. So finally I'm happy and hella cool too.

Does anyone know if these adapters work for fm transmitters. I have been trying to find one that will work with the iPhone but all the headphone jacks dont fit (except for one made by Scosche but I cant seem to find it anywhere). I noticed that all (except for the Scosche) have 2 stripes on the jack and I need 3 stripes.