Group Buy Interest?

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dgatwood said:
The phase problem is much weirder than I thought. When I'm close to the microphone, it sounds out of phase on the label side, but farther back, the out-of-phase sound swaps sides to the non-labeled side. Really bizarre. Must have to do with the headbasket design.

*scratches head*
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How are you judging the polarity of the mic? If you're trying to do it "live" - by listening in headphones while speaking/singing into the mic - you will find your efforts futile. The problem is that your voice is reaching your ears through acoustic methods at the same time that it's reaching your ears through headphones. The resulting mix of phases will give you a completely unreliable idea of what is coming from the mic.

The only way to get a meaningful result is to record your voice (or other source) using the mic, then listen to it in playback.

I apologize if you're already doing this, but many people have been fooled by this kind of error. And it would tend to yield exactly the kind of observations that you've provided.
 
OK, I guess I will request new ribbons. You might find some jewelery shops that do repair (or watch repair) might have the paitience to do this at a good price. They are used to working with delicate assemblies. Perhaps I could request assembled ribbon morors? Most of us can solder wires. Thoughts?
 
chance said:
OK, I guess I will request new ribbons. You might find some jewelery shops that do repair (or watch repair) might have the paitience to do this at a good price. They are used to working with delicate assemblies. Perhaps I could request assembled ribbon morors? Most of us can solder wires. Thoughts?
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I'd much rather have the assembled motors. Something went very wrong at their place and they need to fix it.

I commented here.
 
apl said:
I'd much rather have the assembled motors. Something went very wrong at their place and they need to fix it.

I commented here.
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I agree that they need to fix the problem however, I am looking for a fix that would involve the least work/time. (packing/shipping etc.) I am more than willing to do what I can. Later this week after I get the last 3 orders filled, I will open these mics and see first hand what this involves for a repair. Having retensioned ribbons (by eye) in the past, I think $125.00 is quite steep
 
chance said:
I will open these mics and see first hand what this involves for a repair. Having retensioned ribbons (by eye) in the past, I think $125.00 is quite steep
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Perhaps in the context of a $60 group-buy mic $125 seems steep. But that figure is fairly common, and very fair price for a US-based technician to disassemble a ribbon mic, cut a proper-sized ribbon, corrugated it, install it, set resonant frequency properly, re-assemble the mic, test, pack and ship - and to carry out every step of the process in a timely and professional manner with guaranteed results. Check with Clarence Kane or Stephen Sank.
 
MichaelJoly said:
The figure is fairly common, and very fair price for a US-based technician to disassemble a ribbon mic, cut a proper-sized ribbon, corrugated it, install it, set resonant frequency properly, re-assemble the mic, test, pack and ship. Check with Clarence Kane or Stephen Sank.
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Yeah, you're right to do it properly. When I did it, I just eyeballed it on a guess. and it took about a half hour.
 
The problem with the ACM-3 isn't just that they need to be retensioned, it's that the folds have gone out of the ribbon material.
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this is what worries me about my mic also...when looking at the ribbon, i noticed that the corrugations have been stretched, and are now fairly uneven along the length of the ribbon. i'm afraid that even after re-tensioning, the mic still won't sound the way it's supposed to.

personally, i would be happy with either a couple of replacement ribbons(in case i bust one) or the entire motor assembly - i wouldn't mind(and would actual cherish the opportunity) installing a new ribbon in it myself
 
I got my Reeeeequest
For the shiiiiipping
Ha ha ha haaaaaa ha
Your mom is stiiiinky
:o

Sometime in the next few weeks, when I get my mics, Chance Geppetto is going to turn me into a REAL engineer.
 
Gilliland said:
How are you judging the polarity of the mic? If you're trying to do it "live" - by listening in headphones while speaking/singing into the mic - you will find your efforts futile. The problem is that your voice is reaching your ears through acoustic methods at the same time that it's reaching your ears through headphones. The resulting mix of phases will give you a completely unreliable idea of what is coming from the mic.
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Well, yeah, I know that you can't tell what a mic really sounds like by singing and listening at the same time, but in all my years, I've never heard a mic where it wasn't immediately obvious which one was out of phase. even doing live tests. One side sounds clear, while the other side sounds like large chunks of the spectrum are nulled out.

On this mic, that's true from a couple of feet form the mic., but if I eat the mic, the back side sounds perfectly clean and clear without any obvious nulls, and the front side sounds like lots of frequencies are cancelled. That's very, very different from what I've heard from any other side address mic, so I can only assume it is caused by a combination of the parabolic shape of the headbasket coupled with the short distance between the screen and the ribbon element.
 
dgatwood said:
Well, yeah, I know that you can't tell what a mic really sounds like by singing and listening at the same time, but in all my years, I've never heard a mic where it wasn't immediately obvious which one was out of phase. even doing live tests. One side sounds clear, while the other side sounds like large chunks of the spectrum are nulled out.
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That's EXACTLY what you'd expect if you test it by listening "live". On one side, your ears hear an in-phase signal from both the acoustic and electronic sources, so everything sounds correct. On the other side, you get an out-of-phase signal from the mic, but the direct sound remains properly phased, so things sound REALLY wonky - as if large parts of the spectrum were nulled out (which they were!). And as you move farther from the mic (either side), the phase relationship changes, so the results change. What you're hearing has nothing to do with the mic and everything to do with your testing technique.

This only comes into play on a figure-8 microphone, which may explain why you haven't noticed it in the past.

dgatwood said:
.....but if I eat the mic, the back side sounds perfectly clean and clear without any obvious nulls, and the front side sounds like lots of frequencies are cancelled.
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That suggests that the mic is wired with reverse polarity. If the back side sounds like it's in phase with your voice (when miked closely), then the mic is probably wired incorrectly. This isn't the first time that we've had reports of that issue on these Chinese mics.
 
Ribbon Motors

I think sending the whole ribbon motor is the way to go, and a reasonable request even witht the discounted price, provided that they have a good understanding of the problem and won't make the same mistake again.
 
Anyong that has not recieved the PP request, PM me with the info as it appears on your past Pay Pal invoice
It's hard to recognise your HR handles.
 
Gilliland said:
That's EXACTLY what you'd expect if you test it by listening "live". On one side, your ears hear an in-phase signal from both the acoustic and electronic sources, so everything sounds correct. On the other side, you get an out-of-phase signal from the mic, but the direct sound remains properly phased, so things sound REALLY wonky - as if large parts of the spectrum were nulled out (which they were!). And as you move farther from the mic (either side), the phase relationship changes, so the results change. What you're hearing has nothing to do with the mic and everything to do with your testing technique.

This only comes into play on a figure-8 microphone, which may explain why you haven't noticed it in the past.
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I think I was hallucinating last night. I'm not hearing what I heard last night when I try this again tonight.... Tonight, it just sounds like what I said originally was correct, i.e. that the mics are wired backwards....

As an interesting side note, though, removing the back grille makes the front sound a bit better, so there are definitely internal reflections contributing to the cancellation. I'm seeing definite grille mod potential here.
 
MichaelJoly said:
Chance, this situation needs methodical troubleshooting.
1. Did the factory set tension for proper resonance frequency at the factory using a test jig for this purpose? They need to assure you that they have a procedure for setting resonant frequency and inspection to verify this.
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Just curious, have they assured you of this. The fact that so many of the other branded ribbons have had the same problem makes it seem like this isn't just a problem with this particular batch of mics (or with this particular manufacturer, if the others are made by a different one).

I don't really trust myself to retension my sagging ribbons, and I think that I might not have ordered them if I had known they would have problems. At the same time, I'm not really upset about it, because if I had bought one from another company selling chinese ribbons, I might have had the same problem for more $$. Anyway, it would be nice to have some sort of a replacement ribbon, but it seems like the real issue is finding out if this is something they can really fix. If not, you should warn everyone who's planning on doing the next GB that if they buy a ribbon, it's likely they will have to retension it or pay someone else to do it.

It would be great if they could give us some kind of assurance of their tensioning/inspection process. Am I dreaming though, or are they still unsure of what's going on?
 
Tonight I will be calling China. If I request ribbon motors for all the ACM-3 mics, DOES EVERYONE FEEL CONFIDENT IN THE DIY SWAP? I want to resolve this so we can move on to the next GB. Remember as I posted a while back This company was bought out by another manufacturer in China. (better for us)
 
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