Beyer Dynamic M101 small dynamic omni - any good ?

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clintrubber

Well-known member
Joined
Jun 3, 2004
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5,982
Location
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Hi,

Having searched I couldn't find that much info so let's try here...

I can buy a pair of BeyerDynamic M101 microphones, these are pencil sized dynamic omni mics.

http://www.saturn-sound.com/images/beyer dynamic m101n - omni-directional - dynamic microphone.jpg

Any good ? Any experiences ?
And what's the max SPL these can do ? Couldn't find that.

The combination of omni & dynamic in a pencil-mic is funny to me for some reason, and I'm wondering that if I want omni I'd perhaps better go for a SDC or a dual diaphragm LDC ?

My application would be room-sound and an alternative to try on cabs & percussion.

FWIW, I've seen these 101's being mentioned the omni version of the better known M201 (which is hypercardioid)


Thanks,

Peter
 
I've used them a lot and I just love them. Tese are really good omni microphones.

I used them especially on drums and guitar/ bass amp

If you have a good price, just buy them or I will... :wink:
 
[quote author="Nadege"]I've used them a lot and I just love them. Tese are really good omni microphones.[/quote]
Nice, thanks for your reaction :thumb:

I used them especially on drums and guitar/ bass amp
Aha, so they can take some SPL I understand, good to hear - and exactly where I want to try them on.
I saw a freq-graph, for that partic. mic the response looked a bit 'tilted': straight line but more highs and less lows. What's your impression w.r.t. bass-response ?

You're using them on drums for overheads ?

If you have a good price, just buy them or I will... :wink:
I'll contact you when I don't like them :wink:

Thanks,

Peter
 
I know several people who swear by those on snare drum. They are on my list of mics to pick up someday.
 
[quote author="emrr"]I know several people who swear by those on snare drum. They are on my list of mics to pick up someday.[/quote]

Thanks & aha, another confirmation that these mics can handle loud stuff.

What would be a decent price for these ?

Thanks,

Peter
 
Good to see these are not as rare or uninteresting as I almost started to believe (as based on the little info on them out there, but that was before starting this thread) :thumb:

BTW, an old Beyer catalog mentions these can also be used as talkback-speaker ('keep level below 2V'), will be trying that for fun.

Bye,

Peter
 
Just received a lovely nostalgic datasheet from Beyer.

To my surprise the response graph (which is smoothed & guaranteed not to be the curve any of those mic will exactly have I know) starts falling below 100 Hz and is down by some 5 dB at 40Hz.
Omni's can be rulerflat down to DC, wasn't it ?
Or does the little vent just under the top some influence here ?

The datasheet doesn't mention the max SPL figure, would have liked to know that, but from the words above I knew already that these mics can handle loud stuff.


Cheers,

Peter
 
[quote author="clintrubber"]To my surprise the response graph (which is smoothed & guaranteed not to be the curve any of those mic will exactly have I know) starts falling below 100 Hz and is down by some 5 dB at 40Hz.
Omni's can be rulerflat down to DC, wasn't it ?
Or does the little vent just under the top some influence here ? [/quote]

Aha ! Some further reading of the datasheet... there is no polar pattern figure but it's stated that the Richtkarakteristik is annaherend kugelformig... so while all omni's have of course some directivity at certain frequencies, maybe this mic was meant to be an almost omni right from the start, who knows ?

As I think to understand mics, it'd certainly explain the bass-drop & the vent just below the grille.

FWIW...
 
'101-pair arrived today, looks like a usable set of mics !
Testing them further in a few days (stage/band-setup)

Thanks again everybody for the various info & recommendations :thumb:

Cheers,

Peter
 
Max SPL on most dynamics is limited by your ears or your preamp. You do not want to be near any sound which overloads a dynamic.

> The combination of omni & dynamic in a pencil-mic is funny to me

Why????

> Omni's can be rulerflat down to DC, wasn't it?

You are mixing pattern with sensing technique.

An omni condenser can sense pure pressure. Bass response is limited by capsule air leakage, deliberately so that barometric weather and trunk-slams don't stretch the diaphragm.

Any dynamic senses coil Velocity as voltage. DC response is always zero. Response rises with frequency.

Against this: the coil is heavy and won't move fast easily.

Also: the diaphragm is "small" compared to most sound waves. Response rises with frequency.

I believe the omni dynamic must be resonated mid-band, say 700Hz. Response falls 6dB/8ve either side. Then you press some felt near the back of the diaphram. Acoustic damping gives Q near 0.15 and bandwidth 100Hz-5KHz. At low and high frequencies the felt falls out of range of the other mechanical impedances. The bass falls off. Some mikes use a "bass reflex" plan to bump the bass a bit.

For happy output, the dynamic must be about an inch or two across. That means it is not "small" at the higher audio frequencies. Directivity happens; it is no longer "omni". On-axis rises, off-axis falls; the wise designer lets this happen about the place where overall efficiency is falling at the top of the band, so the on-axis response is flat-ish for another octave or two.

The M101 approximately echos US mikes best known as E-V 635A. Rugged as hell. Good output. Enough bandwidth for many many real world chores. Somewhere is a paper describing the design of a 635A-like omni dynamic. All the response shape features you note are key design compromises.

> these can also be used as talkback-speaker

Research the reason why they know it can be used as a speaker. Interesting story.
 
Thanks PRR for the info. Must catch a train soon, so let's respond in a few installments.

[quote author="PRR"]Max SPL on most dynamics is limited by your ears or your preamp. You do not want to be near any sound which overloads a dynamic.

> The combination of omni & dynamic in a pencil-mic is funny to me

Why????[/quote]
Indeed no reason, it's just based on false associations:
IF [ mic = small ] THEN [ condenser-type AND needs phantom ]
Incorrect.

[quote author="PRR"]> Omni's can be rulerflat down to DC, wasn't it?

You are mixing pattern with sensing technique. [/quote]
Thanks for correcting that, this was indeed the error I made.



[quote author="PRR"]> these can also be used as talkback-speaker

Research the reason why they know it can be used as a speaker. Interesting story.[/quote]
Hmm, something tells me that you mean more with this than simply 'mics being reverse speakers'. :wink:
I did read that for the intended use for this mic-model it'd be very convenient to have the dual funtionality, maybe that's why they added it (~"can be used for speech-signals up to around 2V").


Regards,

Peter
 
The rest...

[quote author="PRR"]Directivity happens; it is no longer "omni". On-axis rises, off-axis falls; the wise designer lets this happen about the place where overall efficiency is falling at the top of the band, so the on-axis response is flat-ish for another octave or two.[/quote]
No polar plot in the pdf further below, but testing confirms directivity for higher frequencies... unsurprisingly of course, otherwise I'd had worlds only 'completely-true-omni'.

An omni condenser can sense pure pressure. Bass response is limited by capsule air leakage, deliberately so that barometric weather and trunk-slams don't stretch the diaphragm.
The dynamic M101 does a few 'card-style' vents just a little below the grille, but I'm not sure how these would fit into this.

The M101 approximately echos US mikes best known as E-V 635A. Rugged as hell. Good output. Enough bandwidth for many many real world chores.
As far as specs go, it looks indeed comparable to the 635A, be it with a bit more Hz's at either side:
http://home.hetnet.nl/~chickennerdpig/FILES/Beyer5/M101_N.pdf
Sensitivity-spec is almost the same as well.

Somewhere is a paper describing the design of a 635A-like omni dynamic. All the response shape features you note are key design compromises.
If it happens to be on-line somewhere, do you have a link ?

Regards,

Peter
 
> IF [ mic = small ] THEN [ condenser-type AND needs phantom ]

Small truth here. Dynamics convert acoustic power to electric power to drive the mike line. They must "catch" enough acoustic power to put sufficient available electrical power on the wire. In practice this means 2 inches or 1 inch, though I recall low-price 5/8" dynamics, and I'm sure there were smaller.

Carbon and most condensers have amplification in/near the head. That does not seem to give a big advantage. Very small omni condensers exist, but they have low output and thus higher relative noise than the 1"-2" wave-catchers. Perhaps the point is that the light diaphragm on a condenser makes response far past 5KHz fairly easy simply by scaling down the diameter. Dynamics can be scaled but run into practical difficulty.

> 'card-style' vents just a little below the grille

Above the diaphragm, correct?

We can have a naked diaphragm or we can have a cavity resonance. Some resonance helps peak the treble, but it should not sound like listening through a shot-glass. I suspect the slits "hurt the resonance" while still leaving enough rim to protect the diaphragm. They may even diffract some sound and spoil the rising directivity so it stays more-omni further up the frequency range than a simple structure this size.

I bet there is a "bass reflex" vent around the connector.
 
[quote author="PRR"]> IF [ mic = small ] THEN [ condenser-type AND needs phantom ]

Small truth here. Dynamics convert acoustic power to electric power to drive the mike line. They must "catch" enough acoustic power to put sufficient available electrical power on the wire.
...
Very small omni condensers exist, but they have low output and thus higher relative noise than the 1"-2" wave-catchers..[/quote]
Outer diameter of this mic is just above 2cm (7/8"), must say I wasn't overwhelmed by its sensitivity (1.3mV/Pa), but it's understandable & it's OK.

BTW, nice that 'wave-catchers', I bet some people reading this may be considering that as a band-name now :wink:

> 'card-style' vents just a little below the grille

Above the diaphragm, correct?
Yes indeed, it must be above it, since it's just a few mm under the top of the mic (or see for instance the pic in this file here
http://home.hetnet.nl/~chickennerdpig/FILES/Beyer5/M101_N.pdf )

I bet there is a "bass reflex" vent around the connector.
Most likely that's what it is indeed, there's a small gap between the outer barrel & the XLR-connector, which for sure isn't sealed.

Thanks again for the info / regards,

Peter
 
Hi all,

I picked up a pair of EV 635A at a flea market in the South of France today. I got the pair for 15 euro including mic cables! When I spotted "Dynamic Omni Directional" on the mic echoes of this thread came back to me. I'm looking forward to trying them when I get home later this week. They look like they've been around the block but for 15 euro I'm happy to take the chance..

Interestingly the flea market started at 6am today. We got there at 7.30am as it was about 90 mins from where we are staying and 5.30am was quite early enough to be getting up for me.

Anyone here actually used one? PRR seems to have some experience. They seem to have been a popular mic Stateside, I've never run into one in Ireland.

Cheers,
Ruairi
 
They are quite good. I'd rather be forced to make a record with a dozen of them than a dozen SM57's.
 
[quote author="emrr"]They are quite good. I'd rather be forced to make a record with a dozen of them than a dozen SM57's.[/quote]

That's good to know. I have sessions almost as soon as I get back so hopefully I'll get the chance to try them out on something.

Cheers,
Ruairi
 
I carry a couple 635's or extra guitar cabinets when doing live sound. You never know if you are going to have enough stands and these sound pretty good when just hung over an amp pointing at the floor.
 

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