All response graphs I’ve seen are based on a 0dB centre line upon which is drawn the relative gain as the frequency increases - e.g.
That’s pretty self-explanatory.
I’m now looking at the graph in the data sheet for another mic (actually Thomann’s SM58 clone), and I don’t understand it.
What is the y-axis scale and why are there two lines in the graph?
Can anyone help explain the second graph to me please ?
Cheers.
Lack of planning on your part does not constitute an emergency on mine.
Also chips are "Plant-based" no matter how you cook them.
Comments
The blue line shows a bass lift, which is usually a result of proximity effect, ie a source closer to the mic.
Studio: https://www.voltperoctave.com
Music: https://www.euclideancircuits.com
Me: https://www.jamesrichmond.com
I’m trying to create a graphic EQ shape to counter the peaks and troughs, i.e. to end up with a flat a response as possible, so I suppose I could just take an arbitrary horizontal line through the graph as a centre point, as, ultimately, the absolute values will change with overall gain levels but the relative gain levels across the spectrum will remain fixed.
Have I got that right ?
Also chips are "Plant-based" no matter how you cook them.
I'll just have to say I don't know, but it seems to me to be a pretty atypical way of expressing a frequency response.
You could email Thomann and ask them.
I can't be bothered to do that maths but you could use the formula dB = 10*log10(Amp) to convert from magnitude to db and repoint the data points to see if it gets close to what you would normally expect.
Or just buy an SM58 and save yourself all that tedious calculation.
Better yet buy a Beta 58.
Studio: https://www.voltperoctave.com
Music: https://www.euclideancircuits.com
Me: https://www.jamesrichmond.com
I’ve done some digging and found out that uPa is micropascals - the Pascal being the S.I. unit of sound pressure. As you say, the scale still doesn’t make sense as the dB values are way too high, unless I’m missing something. According to that graph, the mic outputs between 75dB and 85dB - which seems nuts. Obviously it isn’t and they’re not “dB” in the sense I’m thinking of, but therein lies the problem.
The graph itself doesn’t look crazy if it were on a regular +/- dB plot, so I’m inclined to think the y-axis scale is effectively the same if used for relative values.
Also chips are "Plant-based" no matter how you cook them.
https://images.static-thomann.de/pics/atg/atgdata/document/specs/c_datasheet_141194_v2_en_online.pdf
You don't have anything marked on the X or Y axes.
I would just assume it is meant to be a rough descriptor and relative.
Studio: https://www.voltperoctave.com
Music: https://www.euclideancircuits.com
Me: https://www.jamesrichmond.com
For vocals I wouldn't want a flat response, that little peak in the upper mid is quite useful and you don't want anything below 100Hz or above 14K or so for live vocals
A good cheap 58 clone is the Behringer XM8500 ...... when I was running rehearsals at 2020 people were breaking the 58's so we packed em away and kitted the rooms out with XM8500's and they did the job fine at £20 a pop from CPC
Also chips are "Plant-based" no matter how you cook them.
A dynamic mic can't move fast enough or linearly enough to be used as a ref mic regardless of EQ .... most problems with live sound are to do with bass peaks and troughs due buildup in corner and the adding \ subtraction of waves ..... dynamic mic moving coil is to0 heavy to be moved at low frequencies unless the source is right on top of it
Now that either tells you how good my auto-EQ gear is or how truly shit the sound was before! (I'll give you a clue... it's the latter!).
When it comes to the skillful operation of a 31 band graphic, I'm the equivalent of Joey Essex trying to operate an Enigma machine. If I can get an automatic system to get me somewhere close... ANYWHERE near, then I'll take it!
I've got a little condenser mic I could use instead... Or one of the drummer's AKG overheads.
Also chips are "Plant-based" no matter how you cook them.
The other difference is that, in the Shure graph, the y-axis readings are Relative whereas, in the Thomann graph, they are Absolute - and not expressed in units of much help to the typical end user.
The legend on the Thomann graph appears to read 20uPa/2.83V. If this is a reference or datum point, it would have been a good idea to represent it on the graph as a dotted line or something.