The ECM-8000 is now the EMM-6 and comes calibrated

[anechoic]

And now on sale for $39... hmm.

Sweet! If anyone is interested in saving some dough on my calibrated mics, I'm going to calibrate some EMM-6s and pass the savings on to you!

Calibrated EMM-6's (including cal files on a mini-CD!) start at $70 + shipping.

[Bill Schneider]

Well, I jumped on that. It's too good of a deal to pass up.

[anechoic]

Well, I jumped on that. It's too good of a deal to pass up.

I just ordered the first batch, I'm hoping I can get them and turn them around by Tues/Wed.

[Zilch]

More data, presumably.... 8)

:dothewave:

[NateTTU]

I'm concentrating my efforts on other portions of my ht, but eventually I want to get my speakers calibrated. I'm a noob when it comes to this, could I use this mic to calibrate my system pretty easily? The discounted price is pretty tempting. What other equipment would I need? FYI, I have 5 speakers and 2 subs.

[anechoic]

More data, presumably.... 8)

:dothewave:

And then some. I'm going to be up to my eyeballs in EMM-6's for the next 7-10 days it seems.

[anechoic]

I'm concentrating my efforts on other portions of my ht, but eventually I want to get my speakers calibrated. I'm a noob when it comes to this, could I use this mic to calibrate my system pretty easily? The discounted price is pretty tempting. What other equipment would I need? FYI, I have 5 speakers and 2 subs.

Well whether you buy the mic from PE directly or buy my calibrated units, you're not going to get a much better price so if you think you'll need one in the future, you may as well pull the trigger now. Even if you change you're mind, you'll probably be able to eBay it at the cost you paid for it and get your money back.

As for what else you need, you'll need a software package like TrueRTA, REW or FuzzMeasure to perform the audio measurements and a quality sound card with phantom power to connect the mic to your computer.

[augerpro]

How does this capsule differ than the ECM8000? I'm looking for something that can handle higher SPL with lower distortion.

[anechoic]

How does this capsule differ than the ECM8000? I'm looking for something that can handle higher SPL with lower distortion.

I haven't taken one apart (yet) but me guess is that they're the same so you'll probably be SOL with respect to handling higher SPLs. When I get my next shipment I'll put a couple under the test to see how they compare.

[augerpro]

Cool. If they are better performers I'll buy one from you.

[Shonver]

Image not available

So I took the data points off that plot, measured the MP201 using my freefield method (which is basically the substitution method using another calibrated mic) and plotted a comparison:

Image not available

No tricks, no adjustments, no massaging the data, that's what I got using the same software, hardware and scripts I use to generate curves for all the mics I sell. And yes, that discrepancy at 20 kHz has me a little bothered, but it could be caused by a number of issues including the mic mounting method, the free-field correction curve used by Scantek, etc. Le sigh. However both measurements are will within ANSI/IEC accuracy standards.

Please tell me if I understand this correctly: You measured a BSWA MP201 mic using correction curves from CSL and Scantek, respectively?

Can you show us the EMM-6 response using the Scantek correction curve?

[anechoic]

Please tell me if I understand this correctly: You measured a BSWA MP201 mic using correction curves from CSL and Scantek, respectively?

Can you show us the EMM-6 response using the Scantek correction curve?

I'm not sure I understand your question.

For my normal measurements, I compare the microphone-under-test (such as a Behringer ECM8000 or a Dayton EMM-6) with my reference microphone, an ACO Pacific 7052 microphone which is flat (+/- 1 dB from 20Hz to 20kHz) as confirmed by Scantek. The measurement process incorporates the correction curve from Scantek (for the reference ACO 7052) so that correction curve is already incorporated into all of the plots I've posted in this thread.

[Shonver]

I'm not sure I understand your question.

I'm trying to understand what you've done with the graph here:

Image not available

Can you please clarify what "CSL" response is vs. "Scantek" response?

[anechoic]

I'm trying to understand what you've done with the graph here:

(snip)

Can you please clarify what "CSL" response is vs. "Scantek" response?

Scantek is an NVLAP/NIST traceable calibration lab that professionally calibrated my MP201 microphone. They calibrated microphones using an (expensive) electrostatic actuator and their results have legal standing. The data they got when they calibrated my mic is shown on the third graph of this post ("Microphone Test Report No.: 15338"). The "Scantek response" is that result plotted on a graph I made.

CSL is Cross-Spectrum Labs, aka me. I perform microphone calibrations using a different method. What I did was to calibrate the MP201 using my own ("CSL") method and compared it with the Scantek method. I was attempting to demonstrate that the results I get using my inexpensive method are compable to that obtain by a NIST-traceable calibration lab.

Coming back to the Dayton EMM-6 - my point with the MP201 exercise is that when I measured the two EMM-6 mics shown in this thread, I got different results than the data sheet Dayton included with those mics. Upon seeing those difference, the natural question is "which result is correct?" I wanted to demonstrate that my methods are sound and that my EMM-6 results are correct.

Make sense?

[Shonver]

OK. I understand now what that graph means, but it leads me to the same final question, essentially.

Coming back to the Dayton EMM-6 - my point with the MP201 exercise is that when I measured the two EMM-6 mics shown in this thread, I got different results than the data sheet Dayton included with those mics. Upon seeing those difference, the natural question is "which result is correct?" I wanted to demonstrate that my methods are sound and that my EMM-6 results are correct.

OK. Now this is where I have a slight difference of opinion. Let's, with respect, for a moment put aside the allowable error for measurements of this nature. What I can pick up from the graph is that your measurements have a broad dip from 3kHz~8kHz, followed by a peak at 10kHz (the discrepancy at the very top end you have already mentioned). This tells me one thing: every calibration setup (or, at least, those that have been posted here) has its own "signature". Given this, I wonder how "wrong" the EMM-6's supplied calibration curve really is?

What I want to request from you is: if you generate a difference curve for that plot "Scantek minus CSL" and apply that to a (your) measurement of an EMM-6, will that not be more correct? Could you plot one for us, anyway (it should at least get rid of that 10kHz peak)?

[anechoic]

What I want to request from you is: if you generate a difference curve for that plot "Scantek minus CSL" and apply that to a (your) measurement of an EMM-6, will that not be more correct? Could you plot one for us, anyway (it should at least get rid of that 10kHz peak)?

Ugh... I see what you're asking, but unfortunately it's much easier said than done because the data sets have different frequency values. Let me see what I can put together.

[anechoic]

What I want to request from you is: if you generate a difference curve for that plot "Scantek minus CSL" and apply that to a (your) measurement of an EMM-6, will that not be more correct? Could you plot one for us, anyway (it should at least get rid of that 10kHz peak)?

Difference curves, as requested:

Image not available

[Shonver]

Herb, to get it into a more recognisable/understandable format could you now substract the red BSWA curve from your earlier measurements of the EMM-6, and overlay the Dayton curve? Perhaps show (1) Dayton graph, (2) CSL cal graph and (3) CSL, compensated. I think that "CSL, compensated" would be a fairer graph by which to judge the Dayton curve.

I acknowledge that uncertainties in the differences between the respective measurement setups and the test methods employed have to be considered (for instance the dip in th eDayton graph just above 1kHz), and this makes exact comparisons difficult (that's why there are limits of acceptability), but we should also try to get as close to fair as possible.

I think also that there is now a question regarding the absolute accuracy of your own measurement setup. Whilst your microphone is calibrated to a traceable standard, it does not appear (given the information published here) that you have calibrated your measurement jig . The measurement error would be typically that shown in the red trace, and your calibration should be compensated accordingly. I don't know if others offering a calibration service are in a position to apply such compensation, but you have do have access to references that can be substituted for comparison.

[BobEllis]

IMHO, Herb's measurement technique is more than adequate for the application, especially in light of its low cost to us. Sure there are more accurate methods but let's keep the cost reasonable for DIY use.

[Shonver]

Bob, I don't think there is any doubt about the value of Herb's service. And I absolutely have empathy with your sentiments. But I think that you are missing an important issue here. Herb has put his professional reputation on the line in this very thread. That takes a lot of guts, and I admire him for it. It tells me that he has confidence in the quality of service he is offering. Unfortunately, though, the very data he posted reveals a possible flaw in his setup. I may not be the only one who has spotted this. Others may not be so kind as to point it out; I would rather be seen to be the fool who asked a stupid nitpicky question than to keep quiet about it.

How Herb responds to the questions raised will determine whether he wins the confidence of prospective future customers or not.

[anechoic]

Herb, to get it into a more recognisable/understandable format could you now substract the red BSWA curve from your earlier measurements of the EMM-6, and overlay the Dayton curve? Perhaps show (1) Dayton graph, (2) CSL cal graph and (3) CSL, compensated. I think that "CSL, compensated" would be a fairer graph by which to judge the Dayton curve.

I see what you're getting at here and you may be right. I'm working up the data now, but I have a birthday party I have to get to, so I may not be able to respond until tonight.

[anechoic]

Okay, so birthday cake will have to wait.

Here are the plots Shonver asked for:

Images not available

To be clear, I'm taking the BSWA difference curve from this post and applying it to the "CSL" curves in this post and this post

I included my original curves in green for comparison.

I'll be away from my computer for a few hours so I probably won't be able to respond to any comments before tonight.

[anechoic]

So there's a question about the 10 kHz peaks that show up in my measurements, particularly how they show up in some ECM8000 measurements and not others.

1. There is a very sharp peak in the narrowband data at near exactly 10 kHz. That narrow sharp peak is in fact an artifact of my measurement process, which I am aware of, and which I smooth out when I present the data (although some remnant is left behind because I don't want to distort the overall data).

2. For ECM8000-type mic measurements, there is usually (but not always!) a broad peak centered around 10 kHz. That peak is real, and is caused by the diffraction effect of the ~1inch-long soundwave interacting with the 1/2-inch end of the ECM8000 microphone. I know this because theory tells me that as the mic diameter is reduced, that peak will move up in frequency. I've done measurements of the dbx RTA-M (3/8-inch mic), and the Audyssey APM1 (1/4-inch mic) and the peaks do indeed move up in frequency. I've also measured other 1/2-inch mics like the TEF 04 where they appear to have equalized that peak out of the response.

RTA-M:

Image not available

Audyssey APM1:

Image not available

TEF 04:

Image not available

As I wrote above, not all ECM8000s have that broad peak:

Images not available

I'm pretty sure that the position of the mic capsule in the mic body is responsible for the high-frequency variations. In the above ECM8000 measurements, the capsules were noticeably more countersunk into the mic body than normal. As I speculated before, I'm guessing there is a chance that an excessive shock during shipping could change the way the capsule sits, so I try to be careful to pack my mics to make sure everything is tight.

[Zilch]

So, means *are* available to actually calibrate the mics.

Somebody should clue them in.

[OR, figure out how to do it and charge for the service.... :lol: ]

[JoshJK]

Here's one interesting difference between this Dayton mic and the Behringer in their appearance. It's the metal grille that protects the mic capsule. My Behringer does not have this. I wonder if this grille means anything about the manufacturing consistency of capsule positioning.

[Zilch]

My Behringer appears to have a foam plug there.

[I ain't pokin' it to be sure, tho.... ]

[anechoic]

My Behringer appears to have a foam plug there.

[I ain't pokin' it to be sure, tho.... ]

Don't worry, I poked it so you don't have to

There Behringers just a thin piece of felt glue to the mic capsule casing, like this.

I haven't taken apart an EMM-6 so I can't speak definitely about it. Having a grill doesn't really tell us much, the question is how much play does the mic capsule have behind the grill. If the placement is as varied as the ECM8000, there's not going to be much of an improvement. Then again it's the same price, so I'm thinking there's not going to be a huge difference.

[JoshJK]

At least it's protective. I once poked it out of curiosity, and the capsule got loose. I had to disassemble the body and found that the capsule was only glued very weakly. During this repair, thin wire fell apart from the capsule, and I had to solder it. What a pain! It's so small. I ended up making it work, but only found that there's a wide dip in the midrange that was not there before. And most importantly, my calibration file no longer had its value :cry:

Herb, is it possible to damage the capsule by soldering connection wires? I don't think I overheated it.

Josh

[Dennis H]

Herb, is it possible to damage the capsule by soldering connection wires? I don't think I overheated it.

If it still works, you probably didn't overheat it. Siegfried Linkwitz recommends sealing the back with silicone after doing the 'Linkwitz mod' because it's easy to break the air seal when you mess with it.

http://www.linkwitzlab.com/sys_test.htm#Mic

[anechoic]

If it still works, you probably didn't overheat it.

This.

Yes, it is possible to overheat the mic with improper soldering (which is the #1 reason why I'm not in the mic manufacturing biz) but you would know pretty quick if you damaged something.

[augerpro]

Any updates?

[Dennis H]

Herb's been shipping calibrated mics like crazy. He bought a ton of them when they were on sale.

http://www.hometheatershack.com/forums/spl-meters-mics-calibration-sound-cards/21379-csl-calibrated-emm-6-microphone-sale.html

[anechoic]

For those of you who ordered them, the last group ships out tomorrow. I will have a few left over that I will sell at the same discounted price, but I likely won't announce those until next week.

In general I'd say that the Dayton's are much more consistent than the Behringers.

[CllessuR]

That's nice to know. I had already pulled the trigger from PE before you made the announcement, but I would still like to get a calibration file for this one. I'll contact you after the smoke clears.... :T

CllessuR

[anechoic]

For those who order mics, they've all been shipped.

For those inequiring about leftovers, I have seven mics in stock that I'm selling at the same discounted price . Mics will ship by Wednesdays (sooner for Basic/Basic+ mics).

[BOBinGA]

Thanks. I ordered one from you today.

I had one question that you might be able to help with. What is the effect of measuring the mic say 15 degrees off axis instead of on axis? Would this lessen the 10K peak by making the internal reflections a little less resonant? What do your measurements show? What angle of incidence provides the flattest response? I wonder if this is how PE got the flatter response.

Thanks,
Bob

[anechoic]

Thanks. I ordered one from you today.

I had one question that you might be able to help with. What is the effect of measuring the mic say 15 degrees off axis instead of on axis? Would this lessen the 10K peak by making the internal reflections a little less resonant? What do your measurements show? What angle of incidence provides the flattest response? I wonder if this is how PE got the flatter response.

Thanks,
Bob

The short answers is that as you move off axis, the 10 kHz bunp (if it's there, it's not there for all mics) is reduced although you're not likely to get much of an effect at 15 degrees.

I posted some 0/45/90 deg plots of a few mics over at HT Shack

[anechoic]

One unit left.

Edit: all gone. Thanks guys!

[Stud10]

Thank you Herb. I got my EMM-6 Basic+ today. I am excited to get to the studio with it. I notice the calibration data is saved in files with the extension .FRD. Will RoomEqWizard be able to open the .FRD files, do I need to copy and rename the files with a .cal extension? Any advice on how to use the .FRD files with REW would be appreciated.

Eric

[anechoic]

Thank you Herb. I got my EMM-6 Basic+ today. I am excited to get to the studio with it. I notice the calibration data is saved in files with the extension .FRD. Will RoomEqWizard be able to open the .FRD files, do I need to copy and rename the files with a .cal extension? Any advice on how to use the .FRD files with REW would be appreciated.

Eric

(I really need to include a readme file on the disc to explain this, but I never get around to it)

You should be able to just rename it with a .cal extension and be okay. The .FRD format is just a text format where each line consists of frequency/level (in dB)/phase data separated by spaces (the phase is zeroed out since I don't measure absolute phase).

[Stud10]

Thanks Herb, Brucek over at HTS confirmed this:

REW defaults to looking for .FRD files, so when you Browse for the meter/mic file you can pull down the file type and change it to ALL FILES and select the .FRD file, or even better, simply change the .FRD extension of your file to .CAL and REW will then read them.

brucek

Link:http://www.hometheatershack.com/foru...ote=1&p=196613

So, I can change the extension or open the .FRD files directly in REW . . nice.

Eric

[evilskillit]

I have a question about phantom power for these mics.

Somebody earlier posted that usually people use these.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-576&vReviewShow=1&vReviewRand=601324

For half the price I was wondering if one of these would work just as well or if there would be problems?

http://www.amazon.com/Behringer-Vacuum-Preamplifier-Limiter-MIC100/dp/B000CZ0RME/ref=sr_1_1?ie=UTF8&s=electronics&qid=1255750447&sr=8-1

or

http://www.amazon.com/ART-Tube-Studio-Mic-Preamp/dp/B0002E50MC/ref=pd_sim_e_3

[ThomasW]

No because they're 'voiced' (designed to add distortion) so they don't have flat frequency response

[Dennis H]

Somebody earlier posted that usually people use these.
http://www.parts-express.com/pe/show...iewRand=601324

Personally, I'd hesitate to use one of those for a measurement rig. It has tone controls and you're just assuming the response is flat with the pots in the middle. I guess you could measure it but it seems complicated.

[evilskillit]

Ok so whats the best phantom power for a mic for the least money?