Your testing equipment

[ThomasW]

^%^%$(%*&%$#!!!!!

That comment would be applicable to any measuring mic, not just the audiocontrol one...

The Audio Control mic LIKE every other mic should be used with a cal file.

[Bukem]

What's the point..

Do I really lack the skill to get the message across?

I get the point that every mic should ideally be used with a calibration file. However, you wrote that the audiocontrol mic "is less than optimal" suggesting that even though I could get it calibrated it would still be less than optimal afterwards.

I wanted to find out what it is that makes the audiocontrol mike less than optimal. I paid a fair amount of money for it importing it into europe. It's marketed as a precision measuring preamp and mic so my expectations are high. If it's crap I'd like to know and be done with it so I can make sure I get the right tool for the right job.

Rgds,

Bukem

[Smokinghot]

What's the point..

Do I really lack the skill to get the message across?

I get the point that every mic should ideally be used with a calibration file. However, you wrote that the audiocontrol mic "is less than optimal" suggesting that even though I could get it calibrated it would still be less than optimal afterwards.

I think it might be a lack of reading his responses accurately to be honest. You asked:

I have no clue wether I can use the uncalibrated measurements as input for crossover design.

Although it's better to get it calibrated would you for the time being share your comments and if possible calibration file for this mic?

All of Thomas's replies to you have been saying that you can use the mic as is, but it will not give you accurate feedback without calibration. I never read anything from him that implied that the audiocontrol mic wasn't any good, by design.

Now....

I understand your frustration but could you please just accept the advice given and stop derailing the point of this thread. If you still need assistance you could start your own thread based on the your specific questions.

I'd appreciate it...thanks

[Bukem]

Smokinghot, sorry to have hijacked your thread. Re-reading the thread I still am of the opinion that there's an underlying suggestion. Being clear in the first place would have helped.

Back on topic.

I use a PE WT2 for impedance measurements and T/S parameters. According to Thomas the WT3 is a much better buy though. Very easy to use.

It's no secret I use the Audiocontrol kit for measurements.

What's sparked my interest for a (firewire) sound card and mic preamp is the TC Electronic Konnekt 6: http://www.tcelectronic.com/desktopkonnekt6 I can't comment on it further though.

Rgds,

Bukem

[ThomasW]

AFAIK, the AC mic is no better or worse than any other low cost mic. The AC mic is a capsule mic as is the ECM8000. I don't know if they use the same capsule, but I wouldn't be surprised if they did.

Like all mics, the AC mic should be used with a cal file if the goal is to have accurate measurements for loudspeaker design.

I have a pair of the MP-200 mics. At some point I'll send one to Kim and get a cal file. I doubt it's the claimed +/-1.5dB from 20Hz-18kHz

I use a PE WT2 for impedance measurements and T/S parameters. According to Thomas the WT3 is a much better buy though. Very easy to use.

I've never used the old PE WT2 nor have I commented about it.

At it's now lower price WT3 maybe a better buy than the current S&L Woofer Tester 2. But Woofer Tester 2 does more measurements, so I think it's actually the better long term investment.

[oldbar]

If you are in Europe why not trying this company I have MP-1r-KIT Acoustical measurement kit and i am happy with it.

http://www.content.ibf-acoustic.com/catalog/index.php?cPath=32

[Bukem]

AFAIK, the AC mic is no better or worse than any other low cost mic. The AC mic is a capsule mic as is the ECM8000. I don't know if they use the same capsule, but I wouldn't be surprised if they did.

Like all mics, the AC mic should be used with a cal file if the goal is to have accurate measurements for loudspeaker design.

I have a pair of the MP-200 mics. At some point I'll send one to Kim and get a cal file. I doubt it's the claimed +/-1.5dB from 20Hz-18kHz

Hi Thomas, thank you for your detailed thoughts. It's much appreciated.

I've never used the old PE WT2 nor have I commented about it.
At it's now lower price WT3 maybe a better buy than the current S&L Woofer Tester 2. But Woofer Tester 2 does more measurements, so I think it's actually the better long term investment.

From another thread...

WT3 is a toy, and I know this because I have one. If things like this interest you get WT2 http://www.woofertester.com/wt2product.htm

Obviously I got my numbers mixed up and do apologise for the confusion. I use a WT3, not a WT2.

[Smokinghot]

My suggestion is that you send the mic to Kim Girardin, he'll return it with a cal file for $40 kmgrdn@luminet.net

I decided to take this advice, and wrote KG at the above email addy this morning to see if he would accept my mic. I will update this thread with my experience using his services if he does agree to calibrate my 8000.

Now, I have no idea how quickly KG will respond to my email, so I just have to ask here as well.

...When I opened the packaging to my "used" ECM8000. I was greeted by the distinct odour of cigarette smoke 8O Now..., maybe, I'm just being an alarmist and I have nothing to be worried about, but should I be concerned about this mic's operation, if it was in fact exposed to a smoking enviroment...? :cry:

It's sad to say, but this really eating at me. Should I be concerned...?

[Bear]

In general, it is Not Good for any measurement instrument not designed to measure aerial particulates to be exposed to an environment where there are aerial particulates (e.g., "smoke", heavy dust). This is can be fairly bad with optical gear (what I know best), but I'd expect a mic to be a bit more tolerant, especially if you have it calibrated post-exposure and then don't expose it anymore.

Bill

[Smokinghot]

Thanks Bear...

With any luck, it won't matter. ...at least I hope that's what the lack of feedback means anyway.

:huh:

[JonP]

Well, look at it this way, if any of those smoke particles made it into the mic capsule and deposited on the diaphram... and there was enough to alter the mic response a little bit from the original... it still won't matter since you're getting it calibrated NOW. :T

The above is kind of a humorous exaggeration... I would REALLY doubt that the smoker exposure had any measurable effect on the mic. You could wipe it down with a damp cloth with Windex or something, to clean the aroma off, if it bugs you. (watch getting moisture in the mic capsule, of course!)

[Bear]

Well, look at it this way, if any of those smoke particles made it into the mic capsule and deposited on the diaphram... and there was enough to alter the mic response a little bit from the original... it still won't matter since you're getting it calibrated NOW. :T

The above is kind of a humorous exaggeration... I would REALLY doubt that the smoker exposure had any measurable effect on the mic. You could wipe it down with a damp cloth with Windex or something, to clean the aroma off, if it bugs you. (watch getting moisture in the mic capsule, of course!)

Smoker, huh? Not trying to preach or be overly righteous, but the chemical composition of "smoke" is reasonably complex. Depending upon the unit's exposure, I wouldn't be quite as cavalier about the longer-term effects. Casual exposure? I can agree that it is unlikely to have affected the unit that much.

One other note: Windex + plastic film = degraded plastic, assuming the capsule uses a polypropylene or other similar type of plastic membrane. Ammonia is fairly reactive, as is vinegar (an acid).

Basically, despite the low cost of the Behringer mic, I would advise people to treat it like a measurement instrument, especially if you are going to the trouble of getting it calibrated.

Bill

[ThomasW]

This is a DIY audio forum not a forum for the discussion of the specifics of smoking or smokers. Let's keep the posts to the point and on topic...

FWIW, it's impossible to access the ECM8000 diaphram without destroying the capsule. So any discussion about cleaning it is pointless...

[JonP]

Agreed... (though I'm not a smoker)

I was only talking about the outer surface of the mike body, just to remove the smell. Getting anything in the capsule will very likely damage or destroy it. The Panasonic type capsules typically have a felt cover over the hole, so there's a barrier to smoke, dust, etc between the world and the diaphram.

So, smokinhot... let us see your mic response after it comes back from cal... I'm interested in the results.

[Smokinghot]

FWIW, it's impossible to access the ECM8000 diaphram without destroying the capsule. So any discussion about cleaning it is pointless...

Now it's pointless, because up until your post, I wasn't aware of that cleaning was impossible...

[Smokinghot]

The Panasonic type capsules typically have a felt cover over the hole, so there's a barrier to smoke, dust, etc between the world and the diaphram.

I did notice that felt cover, but also know how smoke can get through pretty much anything (especially something acoustically transparent) and stain whatever it touches.

Essentailly, I brought up my concern about the 'smokey' smell, because I just wanted to educate myself about whether or not this could result in the capsule/diaphram needing replacing, or (what I now know is possible) just a cleaning.

It seems as though my worry is unwarranted, so I'm not going to give it another thought, and just wait till the expert tries to calibrate it. :T

So, smokinhot... let us see your mic response after it comes back from cal... I'm interested in the results.

No problem... of course I have no idea at this point who is doing the work and/or how long it will be before I'll get it back.

[Smokinghot]

Just thought I would update for those that have any interest:

My MobilePre showed up yesterday (thanks mazurek :T ), and I shipped out my 8000 to Kim G. this afternoon. In correspondence, Kim explained that any build up on the mic internals by the smokey enviroment would not matter after calibration.

Thanks all for your feedback.

[Dave Bullet]

Calibrate your mic yourself. The ECM8000s are pretty consistent under 2KHz

Buy a known consistent tweeter. The Seas 27TBFC/G for example. Infact buy 2 (so you can make a system). subtract your measurement from others published and you have a calibration file. I posted on this site about it... have a search - cheers.

[Smokinghot]

Calibrate your mic yourself. The ECM8000s are pretty consistent under 2KHz

Buy a known consistent tweeter. The Seas 27TBFC/G for example. Infact buy 2 (so you can make a system). subtract your measurement from others published and you have a calibration file. I posted on this site about it... have a search - cheers.

Thanks for the suggestion....although about 1wk late...lol.

As it is, I guess I save about 50 going the route of Kim G. I don't have any need for the seas tweets.

May I ask though... How can you expect to get a reference measurement with any driver if you don't know what a true calibrated reference is...? Are you trusting the Seas manufacturer specs...? ...or someone elses published testing..? Please feel free to paste the link to your calibrating thread. I'm sure others who have been following this would appreciate it.

Regardless... I would need a room obsolutely free of ambient noise to trust any thing I did on my own. Otherwise I could be "calibrating" out frequencies that I shouldn't be. I think I've made the right choice going with KG.

[brianpowers27]

I am using a m-audio 24/96 at the PC fed by a Studio Projects VTB preamp. My ECM8000 has been calibrated from 10hz to 24khz via cross spectrum labs in MA.

I measure in ARTA/WinXP64 using dual channel mode. I paralell a voltage probe between the amp and the speaker under test. This voltage probe is connected to the other input of the soundcard. I am not sure how anyone accomplishes this if they are using an all in one soundcard/preamp.

BTW: I own a behringer ub1204 pro and do not use it as my preamp. There are much cleaner options.

[Bear]

Thanks for the suggestion....although about 1wk late...lol.

As it is, I guess I save about 50 going the route of Kim G. I don't have any need for the seas tweets.

May I ask though... How can you expect to get a reference measurement with any driver if you don't know what a true calibrated reference is...? Are you trusting the Seas manufacturer specs...? ...or someone elses published testing..? Please feel free to paste the link to your calibrating thread. I'm sure others who have been following this would appreciate it.

Regardless... I would need a room obsolutely free of ambient noise to trust any thing I did on my own. Otherwise I could be "calibrating" out frequencies that I shouldn't be. I think I've made the right choice going with KG.

Agree with the sub-text here. Assuming a driver "off the shelf" as your reference isn't really a good idea. Differences in testing environments, ambient noise and even unit-to-unit variation can lead to the introduction of significant error. I do not know if Kim follows NIST protocols, but even if he doesn't, I expect they are close enough. You want something that is calibrated in an anechoic environment consistent with how the reference instrument's traceability path has been calibrated.

Given what this type of service/equipment costs for video, spending $100 - $200 on a calibrated instrument is pretty cheap.

Bill

[Smokinghot]

.....I shipped out my 8000 to Kim G. this afternoon. In correspondence, Kim explained that any build up on the mic internals by the smokey enviroment would not matter after calibration.

One last update for those with the same questions/concerns...

I picked up my mic this passing tuesday from the post office. So the entire transaction was about 3wks from door to door, testing/calibrating, and back again. Considering I shipped from Canada, I'd have to say KG has pretty fast turn around time.

I should say the he let me know that he's moving away from international work. Fortunately, I dropped Thomas's name and that I learn about his services through HTGuide in my first correspondence with him. I'm thinking he took that into consideration :T

I haven't had the chance to try anything out as of yet...or even open up the cal file for that matter. However, I do plan on hammering the forum with questions/progress posts when I start R&D on my first project. I'll include my testing equipment experience within that thread.

Thanks everybody for your suggestions.

:^x

[Dave Bullet]

Too late now to post a thread on self calibration. Suffice to say my self calibration compared very closely to other people's calibrations done by an external party.

Yes I trusted Seas measurements initially, then I compared my calibration file and Seas measurements with others which appeared very close. Most ECM8000s are flat between about 20Hz and 2Khz (is yours?) its above 2KHz you have a rise and below 20Hz a droop. Since most people cannot measure below about 50Hz with even the largest spaces, then it is above 2KHz that variation matters.

I have a cheap and cheerful setup (since that was what this post was about). Which includes:
ECM8000 mic (self calibrated based on Seas tweeter)
10m balanced XLR cable
Event AMP1 mic preamp (solid little sucker) - provides 48v to mic
Labotomised Wallin Jig (now works claudio negro cable style, because the cheap high contact resistance switches available in NZ are no good)
Some Soundblaster 16-bit PCI clone card (only good for 44KHz measurements)
Pentium II/450MHz PC running Win98SE

[Smokinghot]

Never too late to expand on a topic. ...Well, maybe it's too late for me, but I'm sure others coming across this thread in a search would appreciate it. :W

I can't comment as of yet, on my mic's response. I still haven't found the time to hook everything together. Needless to say I'm happy with my choice to get KG to handle the cal file. If nothing less, I know my testing will be accurate. (well maybe not accurate but at least not the fault of the mic...lol )

For sake of comparison, I ended up with:
ECM-8000 calibrated by Kim G.
3m XLR cable
M-Audio Transit
Wife's laptop...not sure of the specs

I'm in the process of getting my hands on some resistors to assemble my LspCad test probes.