Infoseite // Balanced Microphone Input to (almost) zero tariff



Frage von beiti:


Special idea / question for the sound Spezis

I have a microphone, which I was not sure whether its XLR output is actually balanced. To test, I created a cable of XLR to stereo mini-jack soldered, and so that the hot signal to the left and the cold signal on the right stereo channel goes. I have a short sound recording in the calculator and made me the waveform views. In fact, the waves of the two channels exactly gegenphasig - hence, the proof for the existence of a symmetrical signal.

When I looked at this picture it seems, I had a sudden idea. If I use a camcorder or an MD recorder with asymmetric stereo input had, I could but that a balanced mono signal. I would just behind the s.Calculator separate channels, the channel signal with the cold phase and then reverse both 1:1 mix. All the advantages of symmetrical recording (a higher level and extermination of the interference), I would get so synonymous, except that instead of merging in the preamp just later in the post-production takes place.

Has anyone ever made? Can this work?
Or is the idea may already ancient and sound Insider long cold coffee?

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Antwort von beiti:

Mir is still a potential problem haggard. Recorder with compressed recording (MD, MP3, etc.) process so the two channels are not completely separated, which then could bring problems. So, only uncompressed recording method (PCM or WAV sound recording) in question.

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Antwort von camworks:

The idea sounds reasonable.

(but still could be that you are overlooking something important)

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Antwort von beiti:

I've tried - and it works!
zum Bild

The following test setup: I have mentioned s.Camcorders via XLR jack adapter symmetric Microphone connected, and is 30 meters with XLR cables between. Then I took a short audio recording made on DV and with my phone intentionally to cable reingestört.
The DV - video via firewire, I have captured the sound and exported as a WAV.
In Audacity, I then start the sound at -3 dB normalized, the stereo tracks split into two mono and the right lane (where the signal it is cold) is inverted. Then the two tracks mixed together.
In addition, I have the left lane (hot signal) is stored separately, and are reinforced by 3 dB (to the volume s.den Mix align); here you can hear how the same Tonstück without Symmetrierung sounds.

The results (as mp3 with 320 kbps) are here:
Asymmetrische Version
Symmetrical version
To these recordings to accurately analyze, recommend a good Headphones.

The noise of the camcorder preamplifier is of course not gone, but the incident interference already. Even before turning on the phones is because something Surrender quietly in the background, whose origin I do not know. The mobile phone also manifests itself as high tone. Both disorders are balanced in the later version disappeared.

Apart from the actual experiment to find synonymous exciting, once so directly symmetric and asymmetric transmission can be compared. In practice, we apply the otherwise only blind (or deaf) s.and do not know whether the symmetry in this particular case has brought benefits.

PS: Those who try to follow myself, can do

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Antwort von camworks:

I have about me again. it can not work properly (if it is synonymous with you apparently works). because the function of the symmetrical wiring lies in the fact that a disturbance to both cables simultaneously consecutively. because this is a signal in the cable phaseninvertiert transported, there is theoretically a 100% extinction of the disturbances (if phase shifts due to the gap in the wire cable has ignored).

in your method works but it is different:
both signals are only "almost" in phase (in reality slightly differently by the distance of the two stereo capsules). The trouble goes simultaneously to both wires and the peak induced (with the same polarity). inverted channel you later, delete the information space (in the form of tiny phase differences) are mutually exclusive (which sounded very probably suffers less) and the peak deletes itself also as desired. the problem is simply that the sound worse, because you wanted some of the shares unintentionally extinction. that is synonymous sure why you're the first, who wants to use this method. ;-)

I hope my explanation is understandable.

you can try, by going with your sound program two sine waves can generate, the two channels easily phase (because this is in true stereo micro yes synonymous makes) and then each s.der same constitutes a Disruption-peak reinkopierst. if you take a invertierst channel and get the result as a curve ansiehst, you have to have the problem of some description. in a difficult material you notice the problem, perhaps not, or at least not as strong, but the higher value (ie pure) which is useful, the more should the error too. tell me about it, what rauskommt!

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Antwort von Login_vergessen:

... me again with the funny phrase of the recently presented audio mind tool: "Perhaps it is not theoretically, but practically ..." ;-)

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Antwort von beiti:

"camworks" wrote: in your method works but it is different:
both signals are only "almost" in phase (in reality slightly differently by the distance of the two stereo capsules).
Since you've misunderstood me. I use no stereo mic but a mono with balanced output. The hot signal, I put on the left stereo channel, the cold (phasenverdrehte) on the right stereo channel of the camcorder. The signals are absolutely identical to the phase rotation and the disturbances. Both will be in the post eliminated simultaneously.

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Antwort von camworks:

true, because I misunderstood you.

demand: how do you have the injection of phantom power? or you take a dynamic micro? with food or a part? and if the micro phantomspiesung works with, not to disturb the camera input (because the space is not designed)?

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Antwort von beiti:

To test, I have a dynamic microphone is used. An Electret Microphone with battery power would just go.

About Phantom adapter I have not thought about. I do not know if the tension in Microphone direction or source here synonymous in camcorder direction.

The idea is still quite fresh; haggard yesterday evening and this morning the first time tested.

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Antwort von Markus:

The idea sounds promising. Only the spot Tonkontrolle likely to be irritating when in unfavorable conditions in addition to the wanted nor any radio listening.

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Antwort von beiti:

"Mark" wrote: Tonkontrolle the spot is likely to be irritating when in unfavorable conditions in addition to the wanted nor any radio listening. Ah, if the event is boring, it is quite handy ... ;)

Irritating but it is very fact that you left the stage right and the right signal phasenverkehrte hear. That sounds like a pseudo-surround. Perhaps one would have to be synonymous because the Headphones umlöten, so that both ears on the left channel gets.

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Antwort von chrisi907:

I got this interesting thread and read times times gebastelt immediately. So hot with Tip, Ring with Cold and mass associated with mass, even with his lines and then Munltimeter durchgecheckt ne Recording made. There's something strangely but escaped at:

zum Bild

The Camera is ne HC1 (although the result is the same s.Mac Pro) and the mic is a condenser with its own power on 9V Battery.
If the mic is broken or what could be the problem?

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Antwort von Markus:

The picture does not look so convincing. Which Microphone because you've used?

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Antwort von chrisi907:

The AKG C 1000 S, actually a symmetrical output should have.

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Antwort von Markus:

Hast Du mal compatriots, whether of the jack soldered you completely into the jack on the camcorder is? If the time is not inserted until it stops, then does not reach all parts of the connector corresponding contact points in the socket.

And did you perhaps synonymous a consumer stereo microphone with 3.5 mm jack for connecting your camcorder to check?

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Antwort von chrisi907:

Jo, tried everything. I will look at another opportunity balanced mic and lend the thing so try to see, perhaps not obs s.Mic lies. And I'll call time of the boys to the AKG whether somehow telediagnosis can.

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Antwort von chrisi907:

The AKG service man synonymous unfortunately knew nothing intelliegentes. For that I now have a diagram of the Mikrofoninnereinen and the circuit will be times on your own with his multimeter thorough.

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Antwort von Markus:

The above information after you have both the XLR selbstgelötete Mini-jack adapter cable as synonymous to the microphone input of your camcorder as a possible cause has already been ruled out.

In this case, it probably s.Microphone lie. Another XLR Microphone should then show whether the fault really lies here.

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Antwort von mov:

"beiti" wrote: "Mark" wrote: Tonkontrolle the spot is likely to be irritating when in unfavorable conditions in addition to the wanted nor any radio listening. Ah, if the event is boring, it is quite handy ... ;)

Irritating but it is very fact that you left the stage right and the right signal phasenverkehrte hear. That sounds like a pseudo-surround. Perhaps one would have to be synonymous because the Headphones umlöten, so that both ears on the left channel gets.


or the right capsule + and - umlöten (swap), then invert the phase of these synonymous.

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Antwort von chrisi907:

"Mark" wrote: The above information after you have both the XLR selbstgelötete Mini-jack adapter cable as synonymous to the microphone input of your camcorder as a possible cause has already been ruled out.

In this case, it probably s.Microphone lie. Another XLR Microphone should then show whether the fault really lies here.


Jo, ich werd me a different mic and lend a look, then obs.

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Antwort von beiti:

"mov" wrote: "beiti" wrote: Irritating but it is very fact that you left the stage right and the right signal phasenverkehrte hear. That sounds like a pseudo-surround. Perhaps one would have to be synonymous because the Headphones umlöten, so that both ears on the left channel gets. or the right capsule + and - umlöten (swap), then invert the phase of these synonymous. That will fail but that the signals in the plug have a common mass.

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Antwort von Schlafsack:

Since there is no fault, everything is in order.

The diagram is only the "hot" connection is a real signal fed. On "cold" connection, s.dem one inverted signal expected is wechselspannungsmäßig nothing. The preamplifier in Tonpult reinforced so the difference between the "hot" and the "cold" signal and no signal voltage minus voltage means voltage signal remains.
The circuit is so structured that an interference is present equally s.beiden connections. If the difference is increased, this means that interference is equal to minus interference "interference away."

Would be an output transformer built-in micro, it would record the two signals ( "hot" and "cold") on the camcorder and links right to work, just as if the developers an additional Micro "Invertierungsstufe" in the circuit have been built. But this is expensive, especially if the quality will not suffer.

I hope that my words are understandable ...

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Antwort von chrisi907:

Yes, exactly what I had finally thought of synonymous and it is true. Why the minus phase gespielgelt transferred completely when you really only need the noise.
Thanks for the confirmation.

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Antwort von beiti:

"Sleeping" wrote: Would be an output transformer built-in micro, it would record the two signals ( "hot" and "cold") on the camcorder and links right to work, just as if the developers an additional Micro "Invertierungsstufe" in the circuit have been built. But this is expensive, especially if the quality will not suffer. Of course, it sounds logical: the main thing is that the disturbances are on the cold channel drauf. What is the circumstance with the inverted signal?
Then I wonder, though, why even my cheap dynamic microphone (Behringer) an inverted signal. Also my SonyMS957 are two inverted signals (stereo) - although it only manufacturer with an XLR jack cable is exposed and thus of 99% of customers never used symmetrically. Any benefit must be ominous signal but inverted.

@ chrisi907:
Perhaps you can now test with intentionally inserted to make disturbances. Then we know quickly whether the extinction of the disorder still works.

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Antwort von chrisi907:

The tests I have done and the thesis is right. Although the internal noise of my HC1 is much greater than 3m of the cord adjacent to Mac and mobile phones, but the difference is yet to be heard.
Why AKG in C1000s no inverter has built (see synonymous s.Schaltbild) is probably the reason that the mic so synonymous with their own power more designed for people who s.mobile recorders or so depends. Given the rather go with a double performance over the + phase as the signal 2 times only half durchzuschicken.

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Antwort von Schlafsack:

"beiti" wrote: Then I wonder, though, why even my cheap dynamic microphone (Behringer) an inverted signal

Quite simply: The two connections of the microphone coil is directly with the "hot" and the "cold" terminal (Pin2 and Pin3) of the XLR plug is connected. So you have car a signal in phase and a signal in opposite phase.

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Antwort von WoWu:

@ Beiti

I do not know if I've understood everything correctly, but if you have a stage on one stereo channel and put the other phase of the Micros on the other stereo channel .... then press it in your monitor MONO times, then everything is gone.
Also effective data reduction systems (depending on model) so that they all share, both links, as synonymous laws (ie, quasi-mono) occur in only one channel to record and then afterwards in the middle represent. Since you through the phase difference of two unequal signals searched and "joined Stereo" so as not identical signal lever you reduce your data from virtually.
The correct way produce a symmetrical input transformer is a small, no preference whether one time or in the device so that a Monomikro synonymous with only one channel is operated.
Finally, yes, both your signal in stereo than in mono synonymous work .... or not?

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Antwort von beiti:

"WoWu" wrote: but if you have a stage on one stereo channel and put the other phase of the Micros on the other stereo channel .... then press it in your monitor MONO times, then everything is gone. That's right. On the way synonymous one can test whether it works.

Quote: Since you through the phase difference of two unequal signals searched and "joined Stereo" so as not identical signal lever you reduce your data from virtually. Whether the procedure with a datenreduzierenden system works, one would have to test. I have it only with DV camcorder probiert, and so has the uncompressed sound.

Quote: Finally, yes, both your signal in stereo than in mono synonymous work .... or not? No, this must not be. The "symmetry recorded" I just s.Rohmaterial. The subject of my own work and must not be mono-compatible. As part of the post is due to phase rotation of the right channel and mix together into a regular mono track.

I'm not so crazy and burn DVDs with phasenverdrehtem right channel. ;)

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Antwort von Markus:

"beiti" wrote: Any benefit must be ominous signal but inverted.
The method is more accurate than an otherwise dead reference signal line "because it is on the interaction between electromagnetic fields (cable <-> interference) that is of course only on the two signal conductors are identical, synonymous if the field strength surrounding the Head comparable.

"Sleeping" wrote: The two connections of the microphone coil is directly with the "hot" and the "cold" terminal (Pin2 and Pin3) of the XLR plug is connected. So you have car a signal in phase and a signal in opposite phase.
And that is the explanation for why the Manufacturer despite rigor still build it. This feature is simply so simple that it is no significant additional costs.

"beiti" wrote: ... and burn DVDs with phasenverdrehtem right channel. ;)
And outside on the cover do not forget, with very large pseudo-surround sound to advertise. ;-)))

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