CSL-Calibrated EMM-6 Microphone Sale

**melberi** · **11-07-09, 01:25 PM**

Quote:

Anechoic wrote:

At what frequency? As you might imagine I'm hip deep in EMM-6s right now, but if I get a chance tonite, I'll run an output impedance sweep.
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500 Hz. My method was quick and dirty, I inserted a resistor of known resistance (~160 ohms) between the mic and preamp and comparing the voltage at preamp to the case without resistor. Input to microphone was provided by a headphone driver right next to mic and the measurement was repeated a few times (in addition to averaging over time in each case in ARTA).

I'd love to get confirmation of the result from a mic or two of yours!

**BK_856er** · **11-07-09, 06:47 PM**

Received my calibrated EMM-6 in CA today - looks great!

Is the serial number a Dayton thing or a CSL creation? I don't see any markings on the mic.

Thanks again for the great service, Herb.

BK

**Dennis H** · **11-07-09, 08:58 PM**

I think the important thing about the output impedance is it doesn't affect the measured mic sensitivity much if at all. Herb did a check a couple of pages back and got essentially the same voltage reading out of the mic whether it was driving his high-impedance Sencore or his low-impedance Presonus. I'd say they're within the normal margin of error for such measurements using very different hardware and software and it's not something we need to concern ourselves with.

Sencore SP395: 6.995 mV (40K impedance)
Presonus Firebox: 6.981 mV (1.3K impedance)

**melberi** · **11-08-09, 03:21 AM**

I can't agree with that. The difference to open loop voltage grows to over 1.5 dB with a 300 ohm source and a 1500 ohm load. If someone is interested in a measured sensitivity value this is a significant difference. If accuracy wasn't a concern, using the manufacturer's stated sensitivity would be enough.

**Dennis H** · **11-08-09, 11:36 AM**

20*log(6.995/6.981) = .0174dB

Maybe, to put this to bed, Herb will have time to do an alternative test that doesn't depend on getting the ARTA calibration right. Plug a splitter cable into the mic, run one leg to the Sencore and measure the voltage. Then plug the other leg into the Presonus (with phantom power off) and see if the reading on the Sencore changes. As usual, I volunteer the mic I ordered to be Herb's test dummy as I'm in no rush to get it.

Edit: I don't know what preamp circuit the EMM6 is using but these mics are all designed to give an accurate voltage into a low-impedance load. For example, Earthworks specs a minimum of 600 ohms between pins 2 and 3.

http://www.earthworksaudio.com/26.html

**Anechoic** · **11-09-09, 08:05 PM**

Quick & dirty EMM-6 output impedance measurement using the voltage divider method, a signal generator and an imedpance-matching potentiometer.

**Noubourne** · **11-09-09, 08:45 PM**

My mic came today.

Ordered a MobilePre, an XLR cable and a pair of RCA-TS adapters.

I think I will be ready to test full-range once the stuff gets in!

Going to bug the out of my friends with this. HA!

**Anechoic** · **11-09-09, 09:10 PM**

Quote:

BK_856er wrote:

Received my calibrated EMM-6 in CA today - looks great!

Is the serial number a Dayton thing or a CSL creation? I don't see any markings on the mic.

Thanks again for the great service, Herb.

BK

The serial number is mine, so I can keep track of the various mics for the inevitable screw-ups. I also have serial numbers for the Behringer mics - I started using my own S/N before Behringer started tagging their mikes.

**BK_856er** · **11-10-09, 12:23 AM**

Quote:

Anechoic wrote:

The serial number is mine, so I can keep track of the various mics for the inevitable screw-ups. I also have serial numbers for the Behringer mics - I started using my own S/N before Behringer started tagging their mikes.

But if the SN is only on the paperwork and not on the mic itself....

I think I'll lightly etch the SN into the base of mine with a diamond-tip pen, just in case I end up with a collection of them some day.

BK

**Anechoic** · **11-10-09, 12:28 AM**

Quote:

BK_856er wrote:

But if the SN is only on the paperwork and not on the mic itself....

I think I'll lightly etch the SN into the base of mine with a diamond-tip pen, just in case I end up with a collection of them some day.

BK

I actually bought stickers that I was going to use to stick the S/N to each mic but decided against it at the last minute because I didn't want to mar the mikes. Maybe next go-round, I'll include the sticker in the case and let the buyer make the choice.

**Anechoic** · **11-10-09, 12:51 AM**

EMM-6 update: the last group of microphones has been packed, labeled and will be shipping out on Tuesday. I have four EMM-6 microphones left. Go get 'em!

After those are sold out, I'll put up a sign-up page for interest in another group-buy, and when I get a minimum number, we can do this again.

**melberi** · **11-10-09, 11:28 AM**

Quote:

Anechoic wrote:

Quick & dirty EMM-6 output impedance measurement using the voltage divider method, a signal generator and an imedpance-matching potentiometer.

Thank you for this. I have to say I expected the impedance to be flatter, but I think the 300 ohms I came up with is a good average from that graph.

edit: I'm also interested in the distortion measurements. A near-field measurement of a 15" Dayton sub came up with ~19% second harmonic, ~119dB @ 50Hz.

**Anechoic** · **11-10-09, 09:59 PM**

Quote:

melberi wrote:

Thank you for this. I have to say I expected the impedance to be flatter, but I think the 300 ohms I came up with is a good average from that graph.

That result does seem rather... odd, doesn't it? I think it may be caused by my "quick and dirty" method. I did another impedance method with slightly more rigor (and a different mic):

That's more in line with what I would have expected, but still higher than 200 ohms.

**Anechoic** · **11-18-09, 03:25 PM**

Well the holidays are almost upon us. I implied in the other CSL thread that I was considering offering a Black Friday special. Given that I'm a handful of names away from pulling the trigger on another EMM-6 group buy, I figured I would combine the existing discount with another offer.

As always, HTS members will get $5 off.

Everyone (including HTS members) will also get $9 off the order. That basically means free shipping for domestic orders of 1 mic and discounted shipping for international orders.

There is a limit for this offer however - it will apply to the first 25 orders only.

I'm still at the sign-up stage, but when I get enough interest in the group up, I'll put up the order page and I expect to start shipping mics within 3 days of closing the order page.

EDIT: belay that post - it turns out PE is sold out of EMM-6's and won't get anymore until January. I'm going to see if I can get s deal on ECM8000's from them or another supplier.

**tnargs** · **11-19-09, 02:34 AM**

Just checking, does this mean the group buy is on hold? I was about to put my name down.

**Anechoic** · **11-19-09, 10:50 AM**

Quote:

tnargs wrote:

Just checking, does this mean the group buy is on hold? I was about to put my name down.

Well EMM-6 groups buys are obviously on hold until January, but I am trying to set up a group buy for ECM8000 right now. If you're interested in the ECM8000 for that price (plus discounted shipping), by all means sign up!

**Anechoic** · **11-19-09, 05:10 PM**

Bad news: I can't get a deal for ECM8000s.

Good news: I may be able to start selling calibrated ECM8000-type mics for *significantly * less than what I've been selling the Dayton's for. Stay tuned.
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