Thoughts about Dayton EMM-6 mic calibration curves

[dlv]

So I just received my order of 3 Dayton EMM-6 measurement mics from Parts Express. My intention is to use them in my system calibration rig so I can roll into a venue, set up 3 mics front/middle/rear with my SMAART/OSM to quickly get traces for the near, middle and far field response in the audience for system calibration.

Any of you have experience with the Dayton EMM-6 cal curves from PE? I'm very suspicious after comparing them across these 3 mics and I've since discovered some threads in other audio forums discussing the cal curves from PE being garbage.

Here's a screenshot of the 3 mic cal curves I downloaded from PE.

I'm inclined to believe these were not calibrated correctly for room measurements. Looks like some strong reflections there in the measurement environment and one of the mics is wildly different from the others.

But I don't know. Maybe they're ok? I don't know if I can trust them. I'm dithering between keeping them or returning them and looking to source the same mics from somewhere like Cross Spectrum. https://www.cross-spectrum.com/measurem ... ayton.html that does (maybe?) a more reliable calibration.

Any thoughts? Thanks!

-Dave

[Seth]

...

I'm inclined to believe these were not calibrated correctly for room measurements. Looks like some strong reflections there in the measurement environment and one of the mics is wildly different from the others...

The calibration curves are corrective. Once applied in your software, the graphed response of a measured signal should be relatively flat. If you flip the graphs top to bottom, it will give an indication of the native response of the condenser element. What they claim to do is compare the response of each and every microphone to the response of "a laboratory standard Brüel & Kjær microphone" and create a unique correction file tied to the serial number of the microphone. I have no idea and no input on whether the calibration files are garbage or dead nuts perfect.

The Dayton mic's are the only one's I'm aware of that do this. Honestly, I like it from an information standpoint. Also that it takes into account variations in production runs and capsules possibly sourced from various venders/manufacturers. Although, I wouldn't suggest using multiples, constantly juggling which calibration file to apply for which microphone you have plugged in at any particular moment. I don't know how other measurement microphones are "calibrated" to flatten their response, whether it's something in the circuitry inside the microphone itself or if the condenser capsules are just better from the get-go. But, it's very nice to just plug the mic in to anything and know you're all set. I have the Behringer one and also the dbx. I've never compared their responses to each other, but get good results with either. I can plug either one into a console directly and view the RTA there, plug them into a DriveRack for auto EQ, or use the console as a digital interface and view the measurements in SMARRT or OpenSound Meter.

The absolute accuracy of the microphone itself isn't super super important for gig work. As long as you can consistently tune to your desired system response curve using the same microphone, it doesn't matter too much as long as you know that curve, measured on that mic, sounds good. The ultimate accuracy in a measurement microphone is more important when comparing loudspeaker data from different sources for either research or component selection.

[Bruce Weldy]

In the dozens of venues and hundreds of gigs that I've done, I've only been able to use a measurement a handful of times. You just can't do it when there are customers already in the room - like most every bar you'll be in. Learn to use and trust your ears. You'll find that the biggest problem indoors is going to be in the 100-250hz range. Clean that up and everything else is just "season to taste".

[himhimself]

Learn to use and trust your ears.

Absolutely the key there! You can get a good starting point using decent equipment for your setup - doesn't have to be perfect, just consistent. And then use your ears. I've seen "perfection" on a graph that sounds terrible.

[Bruce Weldy]

Learn to use and trust your ears.

Absolutely the key there! You can get a good starting point using decent equipment for your setup - doesn't have to be perfect, just consistent. And then use your ears. I've seen "perfection" on a graph that sounds terrible.

Exactly. Don't ever try to set your PA flat. Use a preset curve with a bump on the bottom, a dip in the low mids and then a gradual slope rolling off the high end. Driveracks have that curve in the system if you select it and use the RTA function on it. It's musical and makes sound check much easier.

[Bill Fitzmaurice]

So I just received my order of 3 Dayton EMM-6 measurement mics from Parts Express. My intention is to use them in my system calibration rig so I can roll into a venue, set up 3 mics front/middle/rear with my SMAART/OSM to quickly get traces for the near, middle and far field response in the audience for system calibration.

Unless you have a very sophisticated system you can't separately EQ three different zones, so there's not much point in taking measurements in three zones. Audience center is usually the preferred spot.

[dlv]

Thanks for the responses guys. I didn't really elaborate on my use case. I do some system tuning work with fixed installs (It's been church venues mostly) and have enjoyed doing it and getting better at it. At least I think I am. People seem to be happy with my work. I want to expand that service and hopefully start doing some larger venues and jobs for hire so I'm building a new rig for it. Like Bruce said often on one off show gigs I rarely have time for tuning tho I have done it on some festival gigs where I've set up many hours before the first act starts.

Now given that you're probably wondering why did I go with a $60 mic if that's where I'm at? I really don't trust the cal curves on those things. So I'm thinking the same thing and probably going to return these and do what I should have done in the first place. Get an industry standard. Earthworks M30 would be a choice but that is pushing my budget. A compromise that seems used by a lot of engineers is an iSEMcon EMX-7150. I can get one for about 2x what I paid for the 3 Daytons. If anyone has any suggestions on other options in that $300 - $400 range I'm all ears. FWIW I already spent the coin on an iSEMcon SC-1 for SPL calibration.

Bill's point is definitely valid. I was thinking of the future but perhaps getting ahead of myself. Though I do some work with array/zoned systems again it's been in a fixed install situation where time usually isn't a constraint (other than I'm spending my time doing it). When time allows I can still get away with moving around one good mic in those situations. I can always expand the rig if I start landing bigger paying jobs where I need to capture traces on multiple zones and do it quickly cuz I'm on someone else's clock.

[Bill Fitzmaurice]

I use the Behringer version, it's good enough. Those files show accuracy of +/-1.5dB from 40 to 2.5kHz, +/-3dB from 30Hz. That's pretty damn good, even without using correction. Change the vertical range of that chart so that it covers +/-20dB rather than +/-5dB and you'll wonder what you were concerned about.

[dlv]

Use a preset curve with a bump on the bottom, a dip in the low mids and then a gradual slope rolling off the high end. Driveracks have that curve in the system if you select it and use the RTA function on it. It's musical and makes sound check much easier.

Ya I've found the driverack "reflective room" target curve a good starting point in the shows I've done since I got my Venue360. Only been able to do an auto EQ in two shows so far (time constraints). So far I've found the auto EQ to be a little aggressive on some of the filters and I ended up tweaking them to suit my ears. Might do better if I let it use more mic positions. I assume it does some averaging there. But as you said, it's a good starting point.

I've got some custom target curves I use in OSM for system tuning. Still working on developing those. Definitely not flat. lol

[Bruce Weldy]

So far I've found the auto EQ to be a little aggressive on some of the filters and I ended up tweaking them to suit my ears.

For sure. I'd always smooth out the big cuts and boosts. Then it's the ears.