Combination speaker/earphone baseplate?

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207 comments

  • Ken Gillett
    Ken Gillett

    Well, with many things in life, although I may not have the specific technical training to be an acknowledged expert, I learn as I go along and I've never considered myself dangerous regarding this practice of self education.

    However, that aside, it has been discussed on here previously how for this mod one 'should' use resistors with the earbuds. One reason being cited that it helps to reduce their volume to better match that of the speakers and I can testify that when there is such a discrepancy this IS a problem otherwise. I believe you only use earbuds, but if one ever does switch from speakers to earbuds and you forget to lower the volume, it can start at a painfully high volume. Whether that will actually damage my ears or not I'll leave to the medical experts, but it is an experience I do not wish to repeat and as forgetful as I am, I don't want to have to rely on my memory to avoid that discomfort.

    Now, where was I? Oh yes.

    There is also your statement that the lower the impedance the better yet this is not at all true for a normal amplifier. Damage can very easily be caused by using speakers with too low an impedance and again I can state ABSOLUTELY FROM EXPERIENCE that running the 4ohm earbuds in parallel with the speakers causes the amplifier to malfunction as the battery level falls, to the point where all you get is painful screeching. Once the battery is charged again, all is well, but it is the low impedance which the amplifier is trying to drive that causes it since at the height of the problem, if the impedance is increased (i.e. disconnect or use higher impedance earbuds) the problem does NOT occur. These symptoms were apparent on 2 entirely separate SMH10s, each with the same type of earbuds so this is not conjecture, nor obsessing over problems that do not exist. I wouldn't waste my time on here if the problem didn't exist.

    No I could not control the volume appropriately previously, but it now seems possible. Nothing to do with the overall levels as that is of course trivial to set (as you point out). It was to do with relative volumes but for the life of me I cannot now remember the details so I'll not mention that again.

    Fitting resistors in the +ve line is electrically no different to fitting them in the -ve line, except in this case where the earbuds are joining the two -ve lines from the amp which otherwise are not common. Bridging these directly is probably not a good thing for the amp. It depends on the amp. But with 150ohm between them, it is almost certain not to cause problems. However it doesn't altogether solve the original problem of losing stereo separation etc when directly connected (as discovered by others previously).

    I follow what you are saying in 1. but it does appear to support my assertion that larger value resistors will help. I was just hoping for a qualified expert to be able to confirm either way.

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  • Ken Wagnitz
    Ken Wagnitz

    Perhaps I was a bit harsh, Ken Gillett.  The potential danger is to others when they read misleading comments and take them as fact.
    At the risk of boring everyone with what is dragging out a bit here...

    "it has been discussed on here previously how for this mod one 'should' use resistors with the earbuds"
    Really?  Yep, some people have used resistors, some haven't. Those who suggest it, do so for volume adjustment.  I personally can manage without, mainly because it is impossible to use the switching socket as I do with series resistors.  (I also don't feel an overwhelming need to reduce the earbud volume.) 

    "There is also your statement that the lower the impedance the better yet this is not at all true for a normal amplifier."
    I suggest you re-read my comment.  "as low an output impedance as possible" means the output impedance of the amplifier, not the impedance of the earbuds.  How could you interpret it otherwise?  (Unless you have earbuds which are generators?)  I don't dispute that your 4ohm earbuds in parallel with the helmet speakers can be problem for the Sena amp.  Personally I have never seen earbuds with so low an impedance, even fairly cheap ones.  They are usually 16 or 32 ohms.  Since I switch out the speakers, that is not an issue for me.

    "Fitting resistors in the +ve line is electrically no different to fitting them in the -ve line, except in this case where the earbuds are joining the two -ve lines from the amp which otherwise are not common.
    -Yes, if you totally discount the fact that you are destroying the channel separation with resistors in the ground leads.

    "Bridging these directly is probably not a good thing for the amp. It depends on the amp."
    Did you even read my earlier comment where I said the grounds are bridged in the earphone version of clamp?  Since the same amp is involved with both types of clamp, I deduce from that fact, the earbud connection will be fine with a commoned earth.  I haven't found any problems in my 3 units.

    I don't know if you'd regard me as "a qualified expert".  My working career includes tertiary electronics training followed by quite a few years at Telstra (Australia's monopoly telecommunications carrier) in an area creating prototype and novel circuits, mostly at audio frequencies, later evolving to microprocessors.  I was fairly proficient at using test and measuring equipment.  These days I do software, not hardware.  But my home workbench has always included temperature-controlled soldering iron, digital multimeters etc, and oscilloscope.

    I suggest if you want to take this further, Ken, you email me privately, as others have done.  I will respond to all (polite) emails.

    BTW, I think our home-modified clamps are better than what Sena have come up with.  They either don't ride motorbikes, or don't read our comments, or both.
    Which is a bit sad, because people posting in these forums are probably Sena's most loyal customers, and most likely to promote the products to others.

     

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  • Marc Woo
    Marc Woo

    Sorry about the embarrassment you guys have faced. The story was that we wanted to get your feedbacks for future products or accessories and then try to reflect your feedbacks to the existing project if possible. The development project for the new accessories was around 80% done when we ask your opinions on combination clamp, and many factors already considered in the design. Some of the feedbacks were definitely reflected on the project, while others remain in the original design. Some of them are left as a future work in the new product development project. Please understand the current situation. Again, thank you for your sincere feedbacks and we will try to find the way to give you a chance to evaluate the new accessories anyway. It would be better than you may think. We will get back to you shortly.

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  • Ken Gillett
    Ken Gillett

    Ken Wagnitz, I do seem to have misread your  "as low an output impedance as possible" to mean the impedence of the earbuds/speakers. But that's probably because I saw no relevance in the "output impedance". The amp is what we've got and cannot (realistically) be changed. We were discussing the impedence of the earbuds and speakers so I hadn't noticed your shift of context. My apologies.

    However, I DO want to better match the relative volumes of the earbuds and speakers and this can only be done with resistors and hence I will continue to experiment. There is NO doubt that the higher the resistance I use, the better the separation and there may be well be a value that provides the best compromise between volume and separation/bleed. But I don't know till I try. What I DO know is that all the previously described modifications fail miserably with my Ultimate Earbuds, no doubt due to their low impedance. They were not cheap at almost 3 times the cost of the Etymotics, but they are comfortable and I wish to find a way to use them with the best volume match, least stereo bleed and minimum hiss. So far, my idea of resistors in the ground lead has produced the best results and I think I can improve on that. Maybe not, but worth trying.

    Regarding the A304 (earbud clamp), does that  ground both -ves, or simply 'common' them? Not the same thing of course, but I no longer have one of those to test. The final mod described that involves cutting only 3 traces simply leaves the earbud -ve connected to ground, but there is a fair bit of background noise and interference. So how do Sena do it on the 304? According to others (one here and elsewhere), the 304 is wrong, but how have Sena got it wrong?

    In fact, how do they do it on the new 305? We still have no idea how the new clamps are supposed to get around this.

    As for their admission here that they only asked us when it was too late. I'm not even sure I understand why they admit to this. Why ask at all? Now they really look silly.

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  • Victor Henderson
    Victor Henderson

    Amazing response from Sena. "The development project for the new accessories was more than 80% done when we ask your opinions".. WTF? Really? All the heartfelt posts, all the feedback, all the discussion and Sena never considered it?  Shaking my head..... Sounds like some places that I used to work. 

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  • Redhook88
    Redhook88

    It's already been said, but I want Sena to hear it again.  You miss the mark on this new combo baseplate.  You gave me high hopes that you were asking for our feedback, only to have those hopes dashed when you told us that the product was already 80% done before  you started asking us for feedback.

    I think what the users want is very simple - a baseplate that has speakers plugged into it AND has a jack for plugging in earphones that will defeat the speakers when in use (with no dongle for the earbuds.)

    The updated product requires the speakers to be physically unplugged and then a dongle be plugged in for the headphones.  While this does provide the end result of switching between earphones and speakers, it's way to cumbersome.  

    Just take the existing speaker clamp and turn the aux input jack (which no one uses) into a earphone output jack that will defeat the speakers when earphones are plugged in.  DONE......Please??!!

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  • Ken Gillett
    Ken Gillett

    Something else has just hit me. The announcement of the new 305 and 306 clamps also stated new versions of older clamps to provide greater volume and we wondered how they achieved that. Well on re-reading the announcement I notice they only mention the 303 and the 304 which are both the earbud only clamps, from which I deduce that:-

    - The 301 and 302 are unchanged

    - The volume increase in the 303 and 304 has been achieved by removing the resistors.

    This is doubly bad because:-

    - It appears that they have done nothing about the problem of common ground on earbuds and associated stereo/interference issues.

    - They have resoundingly missed the point again in that earbud volume was NOT what has been complained about. It is the speaker volume that is the problem and it looks likely they have done NOTHING about this.

    Of course the above is mostly conjecture at this stage as we've not seen the new clamps, but don't hold your breath for the improvements we've been crying out for all this time.

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  • Ken Wagnitz
    Ken Wagnitz

    "It appears that they have done nothing about the problem of common ground on earbuds and associated stereo/interference issues"
    There you go again Ken Gillett, peddling misinformation.

    Who says it is a problem and that there are associated interference issues?  The only mention I've seen is from you.  The ground was already commoned on the earbud units.

    I told you to contact me privately if you wanted to continue... well let me say it here since you want to stay public, your suggested setup is crap.  If you remove the resistors totally from your wiring as described previously, the earbuds will still be playing the difference between left and right channels, sounding very tinny and distorted.

    If you insist on having isolating resistors between the two clamp ground leads, I suggest low values, say around 10 or 20 ohms, with high values in series with the +ve leads to the earbuds.  That way you won't just be playing the difference between the two channels.  (Unless your wiring is not as you described it.)

    Ken, getting fed up with pure conjecture.

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  • Ken Gillett
    Ken Gillett

    What's your problem Wagnitz. Why do you keep saying I have invented these problems (e.g. stereo cross bleed and interference) when they have clearly been previously reported and discussed by others here and in other (linked-to) forums. In other words, I am NOT the only one, nor even the first to experience and report these problems.

    I haven't contacted you privately as I have no desire to be in communication with you since I did not consider it a worthwhile exercise. Seriously, if you don't have anything better to do than post unhelpful and rude comments on here, then I suggest you don't post anything at all.

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  • Ken Wagnitz
    Ken Wagnitz

    Well I'm sorry that you find my comments unhelpful, Ken Gillett.  I think that is because you don't read them carefully enough.

    My last point was that a common headphones ground hasn't been seen by anyone to be a cause of problems, and that indeed the standard earphones clamp has a common ground.  I've pointed out the cause of your "stereo cross bleed and interference", twice.  I've suggested a solution which allows you to retain separating resistors in between the grounds (not necessary in my opinion, and evidently Sena's as well).  Perhaps my memory is failing me, but the only person recall reporting any "stereo cross bleed and interference" is YOU.  Where pray tell is a link to reports of others with these problems?  Have you even considered or tried my suggestion re resistors?  If not, why not?  If you have, what were the results?

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  • Ken Gillett
    Ken Gillett

    Well you're right I am trying to not read your posts, but not doing very well I'm afraid :-(

    As you are STILL insisting the problems are all of my invention, then I suggest you actually read the forum thread linked to by Gennadiy Tsygan who I believe is the first to actually perform clamp modification:-

    http://www.advrider.com/forums/showthread.php?t=828750

    He posted the above link to this thread on September 23, 2012 18:57. I think ALL the problems I have mentioned are discussed in that thread. Now, please give it a rest and stop denying these problems exist and/or claiming that I 'invented' them.

    As for the technical merit of your posts, well is there any? You do appear to have misunderstood my explanation of what I've done and I have no desire to clarify that misunderstanding, so I again suggest that you drop it and move on.

    On a slightly different note, has anyone any idea of exactly when the new clamps will be available.

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  • Ken Wagnitz
    Ken Wagnitz

    "Gennadiy Tsygan who I believe is the first to actually perform clamp modification"
    His advrider post was 23/9/12.  My post here, stating I'd done my mod, was 27/2/12.  I posted a link to photos of the mod, 21.5.12.
    It doesn't matter who did the mod first, but on the evidence of those dates, looks like I did it before 'genka'.

    'genka' initially used only one of the earths.  This was mentioned by StuartV, who said "I have not done the additional mod of adding a ground to R-. genka did it and reported the stereo separation to be greatly improved."

    The only person who reported a problem other than stereo separation in that thread was 'phubner'.  'genka's response was that he'd done something wrong.

    So the reference link points to people who made wiring mistakes.  Naturally they had problems.

    I've modified 3 headsets which work well, documented the method, and I know others have successfully done the same mod.  I've explained why resistors from the separate amp grounds to the common earbuds ground will cause stereo image problems.  I have one of each type of clamp, the speaker version and the earphones version.  I've traced out the circuits of each to guide my solution design.

    Readers of this thread must be getting very sick of the sniping.  Its not what forums like this are for.  This is my last response to your misinformation, Ken Gillett.

     

     

     

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  • Biraz340
    Biraz340
    This is fun....


    image.jpg
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  • Ken Gillett
    Ken Gillett

    Ken Wagnitz wrote:
    "Readers of this thread must be getting very sick of the sniping"

    I agree, so stop doing it. I don't give a toss about who modified what first, I was merely pointing out that I have not invented the problems - they were previously reported by others. This seems to be the fact you (Wagnitz) cannot grasp.

    I have no wish to continue with any argument, but I DO want to get to the bottom of how best to modify the current clamps. Ken Wagnitz has his method which involves an external switching mini jack socket and although this means speakers are disconnected when the earbuds are inserted, it is not a solution for those who don't want extra paraphernalia dangling from their SMH10. The modifications I have been testing and discussing are those that re-purpose the input socket to become the earbud output. This I believe (as it would appear do others) is the optimal solution, given what we're starting with. A bit tricky to insert the jack plug the first few times, but I've found it became easier and soon ceased to be a problem.

    However, there are some electrical issues to deal with, even after correcting the stereo connections. It may well be that Wagnitz' solution does not suffer from these due to the fact that his method avoids both earbuds and speakers being connected in parallel. That's as may be, but doesn't help those who wish to use the MP3 input jack as mentioned above. If anyone has been able to source a switching jack socket that could be used to replace the original on the PCB, then I'd like to know. The only ones I've found seemed too different to fit on the PCB.

    I've yet to resolve how the 304 clamp deals with the independent L & R -ves? I ask because recent testing has shown that using the 304 with Apple ear buds (std. stereo jack plug presumably wired correctly) in the correct ears, left channel comes out of both sides and right channel comes out of the left side only. This is with a new and unused (and unmodified) 304. There has been some criticism of this clamp, but has anyone else actually tested the 304 for correct stereo imaging? Has Sena really made such a goof and in which case, what exactly is the goof? How have they connected things that results in this mix up?

    I've just spoken to my supplier and they have no knowledge of the new 305 and 306. Anyone else heard anything about their availability?

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  • Marc Woo
    Marc Woo

    In order to thank to all of you who participated in this discussion, we would like to give you a chance to evaluate the new clamp kit for free. The people who post the thread before this notice would be the ones who are qualified for free product evaluation.

    Please send the email to marketing@sena.com with specifying your shipping address and helmet type (to select basic clamp kit or full-face clamp kit).

    Then, we will ship one unit of the clamp kit to you when available, either A0305 or A0306.

     

    http://www.senabluetooth.com/products/acc_SMH-A0305.php

    http://www.senabluetooth.com/products/acc_SMH-A0306.php

     

    Even though some feedbacks were not reflected in the current products, it would be applied in the future ongoing projects.

    Again, thank you for all your participations and sorry about the situation that some feedbacks were not applied on time.

    We will try our best effort to provide better products and solutions for us, riders. Enjoy riding!

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  • Stuartv
    Stuartv

    Awesome! Email sent. I would be more than happy to check one out in person and revise my opinion, if the in-person eval works out well.

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  • Redhook88
    Redhook88
    That is really cool! It makes me feel really good about being a sena user/customer. I have sent my email in.
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  • Regulator26fs
    Regulator26fs

    I think this is a great offer. I've sent my email and plan to try it on my Nolan N-103

    THANKS SENA!!

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  • Tom Balaban
    Tom Balaban
    Remarkable offer! Thanks, Sena. Email has been sent.
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  • Tim Jones
    Tim Jones

    Wow, that really is a remarkable offer. Email on the way Sena.

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  • Amorris3211
    Amorris3211

    A very generous offer and I expect to provide prompt and serious feedback after evaluating.

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  • Dave Yeager
    Dave Yeager

    Quite a pleasant surprise.  Well done Sena.  A good investment in feedback from your enthusiastic users.  Email sent.

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  • Gordon Navecky
    Gordon Navecky

    Thank you for the chance to test the new clamp. My email as been sent.

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  • Biraz340
    Biraz340
    Thanks, can't wait to try it out!
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  • Dan Heming
    Dan Heming

    Definitely a great gesture.  I'm looking forward to trying it out to see if it will work for me.  

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  • Kp52r11
    Kp52r11

    does it makes sense to add a toggle button?

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  • Stuart Donaldson
    Stuart Donaldson

    Thanks for making this available to us. It will give us a chance to test it and see if it works for us.

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  • JSTRUBE
    JSTRUBE

    I had the opportunity to speak to the SENA rep at the BMW MOA Rally in Salem.  I purchased a dual set and was excited to hear that SENA was coming out with this option to use both speakers and monitors.  Previously, I used a modified Scala setup with mixed results.  I love the monitors, didn't bond with the Scala.  After a demo of the SENA, I was hooked...

    I'm glad to see this product come to fruition, but am not sure after looking at the photos, why they would have an alternating plug for plugging in helmet speakers or a cord for monitors.  The last thing I want is more cord for my monitors!  Speaking as someone who has only seen this new plate in photos, I wonder why the engineers didn't use a stereo plug right on the unit, with a built in cutout for the helmet speakers.  Plug the unit in, speakers cut out.  This technology has been around for decades.  My 1970's era cassette player would work this way...

     

    Seems like a more elegant solution than having to unplug your long dangling monitor cord and plug in your helmet speakers, hoping the cord didn't get stretched, speakers pulled out, etc. THat small connector just looks like a failure point to me.

     

    Thanks,

    John.

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  • Biraz340
    Biraz340

    I received the new clamp 305 in the mail today.  I already have it on the helmet... Just need to take a test spin this weekend.  I like the the new earbud hook up.  The old earbud connection would always pull out and tear the wires.  Hopefully this will be a better fix.  Thanks SENA!!!!! for allowing us to try this for FREE!!!

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  • Ken Wagnitz
    Ken Wagnitz

    I've received mine also, thanks Sena.
    My first thought was that the microphone lead is heading in the wrong direction.  I'll see if it's an issue.

    I plan to attach the new clamp to my wife's helmet, using the lovely small microphone on her flip-front Nolan.
    She is currently using a boom-mic, which is a pain for her to keep re-adjusting.
    If the mic lead isn't long enough to loop around the flip hinge, I'll just lengthen it.
    I may also end up putting in a 3.5mm socket to restore auto speaker/earbud switching.

    Sorry Sena, that is one part you didn't get right, along with the extra length of cord if using earbuds.

    But I love that mic.  (I did get one previously with the earphone clamp I bought.)
    You should probably sell that as a part on its own.

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