Yes incorrect, this needs to be corrected. Where is the switch/ reed relay?
In mics i've seen, the switch connects XLR pins 2 and 3 together, to achieve the muting.
Sennheiser MD431 electronics repair?
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In mics i've seen, the switch connects XLR pins 2 and 3 together, to achieve the muting.
Again, I don't want to diss this mic, I just want to point out that it is clearly not popular in France.
These direct relatives being the 431-II, 531 and a few variants, I think...?
Apparently it is not available as a wireless head, although I think I remember seeing on TV hand-held wireless with the same recognizable basket and grille.
I have seen it and run a simulation.
Of course the direct short near DR5 is a mistake.
The value of capacitors and resistor are dubious.
R5, quotes at 300r, but the picture tells me it's 10k.
As for capacitors, 4.33 and 15.77 are not normalized values. I suspect they measured that, but they were actually nominal 4.7 and 15uF.
rock soderstrom
Tour de France
Yes, true. The 431-II and 531 are the only close relatives to the original MD431 AFAIK. They sound pretty silmiliar to my ears but Sennheiser has changed some components over the years. Some claim the newer models got more bass than the original...
pic from GS: left original MD431, right MD531(=MD431II)
I also thought at first that there was a wireless version, but that's not true. There was a wireless Sennheiser mic that looked very similar to the MD431, but it was actually a condenser microphone. A former colleague just confirmed this to me. I have corrected the relevant post, I was wrong.
Sennheiser must have had problems fitting the battery and the transmitter into the MD431, which doesn't surprise me, given the opulent inductors that were built into it.
I do not know how similar the MD427 and MD429 are. I think they are of a different origin although somewhat similar in sound. Sennheiser has managed to develop a signature sound across all models like few other companies before. I hear this Sennheiser "sound" even in their headphones.
Just imagination?
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You see the MD431 used a lot in live German TV music broadcasts ,
Choose any band you care to hear , find a youtube video of them playing in Germany in the 70's or 80's , you can be almost certain they'll be using the MD431 , from the TV studio to the concert hall to stadium .
The German Broadcast industry used these mics with external transmitters as well ,
but you do also see a later radio mic version with the same headbasket style and an antenna sticking out the end . (that must be the one Abbey mentioned)
Theres codes of practice in the broadcast industry , they only change over geological time scales ,
of course it varies a lot depending on jurisdiction ,
The way Id envisage using a HPF is at the preamp input , its then under the control of the opperator not at the mercy of what happens up on stage .
Ive seen the Langevin 255A HPF ,
it roughly does what I want but its designed for 600 ohm termination ,
It also contains inductors .
How can I best create the shape of filter I need in this application ?
do I need to include the inductive element , or will C and R alone do ?
Choose any band you care to hear , find a youtube video of them playing in Germany in the 70's or 80's , you can be almost certain they'll be using the MD431 , from the TV studio to the concert hall to stadium .
The German Broadcast industry used these mics with external transmitters as well ,
but you do also see a later radio mic version with the same headbasket style and an antenna sticking out the end . (that must be the one Abbey mentioned)
Theres codes of practice in the broadcast industry , they only change over geological time scales ,
of course it varies a lot depending on jurisdiction ,
The way Id envisage using a HPF is at the preamp input , its then under the control of the opperator not at the mercy of what happens up on stage .
Ive seen the Langevin 255A HPF ,
it roughly does what I want but its designed for 600 ohm termination ,
It also contains inductors .
How can I best create the shape of filter I need in this application ?
do I need to include the inductive element , or will C and R alone do ?
Appears to be a magnetic reed switch in the MD431 for on/off , it probably reduces switch pop as well as the physical impact noise of a traditional switch contact .
The same method might be used in the MD441 to switch the filter . a pair of changeover reed relays similar to below with a magnetic actuator might work
The same method might be used in the MD441 to switch the filter . a pair of changeover reed relays similar to below with a magnetic actuator might work
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rock soderstrom
Tour de France
As mentioned above, the wireless mic, which looks very similar to the MD431, is a condenser microphone. This was also super widely used and is called SKM 4031 (K stands for "Kondensator", D for "dynamisch").
Technically it doesn't have much in common with the MD431, although it sounds similar in my memory. But it was a while ago when I used it for the last time...
https://www.ebay.de/itm/25578653651...W6go2BmC0V4ECOfVoYUWAOtCrRBhHRBBoCHQoQAvD_BwE
Yes, that's probably the one I remember. Similar aspect, different guts.
I've found that, short of using a fully variable HPF, the most operationally useful option is a system switchable between bypass, 2nd-order at about 40-60Hz and 1st-order at about 150Hz.
Similar to AKG C414B TL. Flat/75Hz 2nd order/150Hz 1st-order.
You can't escape inductors for 2nd-order.
I has been awhile since I tested an MD 431 II. Sennheiser claims it is good for "vocals, speech, and broadcasting." This microphone has long been touted by computer speech recognition resellers as "the" best and most accurate speech recognition microphone on the entire planet" (a view I do NOT share, but that is what THEY claim, nonetheless.) As such, it is not surprising the higher frequencies are rolled off. Communications grade audio is generally limited to between 100 and 3000 Hz - adding in some harmonics for music might require up to, say, generally around 10,000 Hz - generally speaking - so it does not surprise me if it lacks luster at higher frequencies. The Shure Model 522 is intended as a communications speech and paging microphone, limited to something like 200 to 6000 Hz, which has even noticeably diminished high end response, especially compared to other dynamic microphones intended for singing and general use, but my point is only to suggest the MD 431 is not intended to be bright and cheery at the higher frequencies, focusing more on broadcast speech than other uses, despite its 40 -18000 Hz specification. I wonder whether the MD 431II simply is less exciting in the upper reaches by design or its intended use.
This comment is offered solely as a general observation for discussion, not a technically expert opinion ... (he typed, as he reached for his Teflon-coated suit ...)
/ James /Well, the guys at the marketing dept have to find something to justify their salary...
What do "computer speech recognition resellers" know about pro audio?
I have a feeling this lacklustre is the result of designing for specs (flat response) rather than for euphony. The most successful live vocal mics are known to enhance parts of the spectrum that result in a bigger-than-life sound.
Another mic that was designed along the same lines is the AKG D224, very flat and extended frequency response, due to two-way design.
Touted to be "the dynamic mic that sounds like a condenser", it never caught as a vocal mic, because of its neutrality. Reliability issues (very fragile HF capsule) put the final nail in its coffin.
raketenmann
Well-known member
I probably just need another MD431 - probably my microphone is working with no issues and is intended the way it sounds - but for a mic in this price range and intention for live vocals, I thought it is impossible that it sounds dull compared to an SM57. Actually I compared it to around 3 or 4 vocal mics (SM58, Audix OM3, Sennheiser BF530 and Heil PR20) and it sounded dull compared to all of them...
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Its very much the German equivalent to the 58 in terms of usage , of course its in another league performance wise ,
Sehhheiser used do a phantom power supply for condenser mics with a three position HPF , maybe the principle is adaptable to dynamic capsules ?
Sehhheiser used do a phantom power supply for condenser mics with a three position HPF , maybe the principle is adaptable to dynamic capsules ?
I wouldn't say they're rolled-off, rather that they are not hyped like in an SM58.
Which are all known to hype the presence range, so what you perceive as a lack of HF is probably a lack of presence.
In comparison, teh MD431 may seem to lackappeal.
It's an interesting circuit.
It could be used with dynamic mics, for sure (pun intended). The upper part is converter, which takes the battery voltage
The lower part is an active 2nd-order balanced high-pass filter, powerde directly by the battery.
Unfortunately the resolution isn't good enough to see the component values, but it's clear that the filter is switched between a lower frequency with a higher Q (slope) and a higher frequency with a lower slope.
The type of FET is illegible, but I think one of the usual suspects (2SK/LS170, 2SK/LS389) found in in-line mic boosters could be used there.
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My appologies I think that should be a hi res version,
Could phantom power be used to power the HPF circuit . ie from console, audio interface or other source ?
Canford audio do a similar power unit for condenser mics , it has 4 HPF settings and 4 positions of attenuation .
Passive really is the way I want to go if possible , inductors suitable for low audio frequencies tend to be a bit large to fit in an xlr adapter and difficult to find ,
they also tend to use pot cores ,
Maybe I should buy the Langevin 255a just to see how its done in the old days ,
EMRR didnt find the frequency characteristics particulalry usefull , but theres always the chance to modifiy the turnover frequencies a bit to suit a particular mic better .
I did a HPF for hi-z input before , 12 position rotary , just RC , I juggled the values until I found a pleasing increment between the switch positions, everthing is relative to the large diaphragm CF tube mic that feeds it ,
Right source ,right micing technique and its like a single knob tone control, little else in the way of EQ treatment is required to put a good signal to tape .
Could phantom power be used to power the HPF circuit . ie from console, audio interface or other source ?
Canford audio do a similar power unit for condenser mics , it has 4 HPF settings and 4 positions of attenuation .
Passive really is the way I want to go if possible , inductors suitable for low audio frequencies tend to be a bit large to fit in an xlr adapter and difficult to find ,
they also tend to use pot cores ,
Maybe I should buy the Langevin 255a just to see how its done in the old days ,
EMRR didnt find the frequency characteristics particulalry usefull , but theres always the chance to modifiy the turnover frequencies a bit to suit a particular mic better .
I did a HPF for hi-z input before , 12 position rotary , just RC , I juggled the values until I found a pleasing increment between the switch positions, everthing is relative to the large diaphragm CF tube mic that feeds it ,
Right source ,right micing technique and its like a single knob tone control, little else in the way of EQ treatment is required to put a good signal to tape .
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GeorgeToledo
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I donāt disagree with you.
Having worked with Prince and Foos, the mic looms larger in my mind than it does on the rental market.
But I will also mention that just because you donāt see it on rental lists doesnāt mean that major rental companies donāt actually have it, along with plenty of other stuff that isnāt on the āfor everyoneā lists.
