Topic: SP-CMC-4U Mics

[poorlyconditioned]

What I don't understand is why SoundPros have not caught on and offered three wire battery boxes.  They are missing a *huge* market here.

They'll just tell you need phantom power. 
But I *really* do agree...

I'm not at all trying to bad-mouth Sound Professionals, but you know I asked Chris (Sound Pro Chris) a bunch of questions and got *completely* different answers from what other technical minded people on here told me.

Here is the problem with the A-T mics as I see it.. Number 1 the distortion figures they are using are not accurate.. These mics do distort badly I have measured them at 114db at 1k these mics have a distortion that is almost 15% that is VERY HIGH! I measure my own mic capsules from the factory they are 10% typical but after my mod the AT mics measure 0.5% and my mics measure 0.5%. So getting the mod done to these mics saves them from distortion but you do sacrifice some level that's why after doing the mod you should invest in a preamp.. To run your mics unless your always taping loud shows then you don't need a preamp in most cases..

Chris Church

I find people that are using the MT do need a preamp after my mod because the noise floor in the MT preamp is bad to begin with. And when you need the extra gain from the MT it brings up the noise floor too much, that being said the preamp in the Edirol R-09 is much better and more often then not for most loud shows not needed..

Hey Chris.  I think the problem is AT mics were *never* designed to run as "two-wire" at all.  If you look at any of the numerous AT powering options, they use a three-wire circuit.  Even the power modules that are battery/phantom split the battery voltage so that half is across the FET and half across the (source) load resistor.

As far as "not enough gain" that is subjective.  Sure, if you're trying to run into a NJB3 or Iriver, you've got a problem.  But several line inputs, like Edirol R01/R09, and Minidisc have enough gain to bring this up nicely for any amplified music.  I think they might add 10-15dB or so but that is quite enough.  That is why I've been using my MD so much even though I've got a lot (!) of other gear.

  Richard

Richard they are not really three wire capsule all they are is two wire capsules that have a separate ground wire to the case. The red wire is the signal the Yellow is the negative if you remove the ground wire the mic will still work but will be noisy in a true three wire capsule it will not work..

This is the same as the other capsule I use for my mics. I could be wrong but that's what I have discovered.

I gotta disagree with you there!

AT and yours are both three wire.  Red is the drain of the FET, Yellow is the source of the FET and shield is ground (of the capsule).  The other end of the capsule goes to the gate of the FET.  For two wire you short yellow and ground (at the 3.5mm stereo plug, usually).

Your mics have three wires too, +, audio, and ground.  Some variants have a source resistor (eg., 2.2k) soldered between audio and ground.

  Richard

[Church-Audio]

What I don't understand is why SoundPros have not caught on and offered three wire battery boxes.  They are missing a *huge* market here.

They'll just tell you need phantom power. 
But I *really* do agree...

I'm not at all trying to bad-mouth Sound Professionals, but you know I asked Chris (Sound Pro Chris) a bunch of questions and got *completely* different answers from what other technical minded people on here told me.

Here is the problem with the A-T mics as I see it.. Number 1 the distortion figures they are using are not accurate.. These mics do distort badly I have measured them at 114db at 1k these mics have a distortion that is almost 15% that is VERY HIGH! I measure my own mic capsules from the factory they are 10% typical but after my mod the AT mics measure 0.5% and my mics measure 0.5%. So getting the mod done to these mics saves them from distortion but you do sacrifice some level that's why after doing the mod you should invest in a preamp.. To run your mics unless your always taping loud shows then you don't need a preamp in most cases..

Chris Church

I find people that are using the MT do need a preamp after my mod because the noise floor in the MT preamp is bad to begin with. And when you need the extra gain from the MT it brings up the noise floor too much, that being said the preamp in the Edirol R-09 is much better and more often then not for most loud shows not needed..

Hey Chris.  I think the problem is AT mics were *never* designed to run as "two-wire" at all.  If you look at any of the numerous AT powering options, they use a three-wire circuit.  Even the power modules that are battery/phantom split the battery voltage so that half is across the FET and half across the (source) load resistor.

As far as "not enough gain" that is subjective.  Sure, if you're trying to run into a NJB3 or Iriver, you've got a problem.  But several line inputs, like Edirol R01/R09, and Minidisc have enough gain to bring this up nicely for any amplified music.  I think they might add 10-15dB or so but that is quite enough.  That is why I've been using my MD so much even though I've got a lot (!) of other gear.

  Richard

Richard they are not really three wire capsule all they are is two wire capsules that have a separate ground wire to the case. The red wire is the signal the Yellow is the negative if you remove the ground wire the mic will still work but will be noisy in a true three wire capsule it will not work..

This is the same as the other capsule I use for my mics. I could be wrong but that's what I have discovered.

I gotta disagree with you there!

AT and yours are both three wire.  Red is the drain of the FET, Yellow is the source of the FET and shield is ground (of the capsule).  The other end of the capsule goes to the gate of the FET.  For two wire you short yellow and ground (at the 3.5mm stereo plug, usually).

Your mics have three wires too, +, audio, and ground.  Some variants have a source resistor (eg., 2.2k) soldered between audio and ground.

  Richard

Ok I stand corrected I have never opened up an AT mic.

[poorlyconditioned]

What I don't understand is why SoundPros have not caught on and offered three wire battery boxes.  They are missing a *huge* market here.

They'll just tell you need phantom power. 
But I *really* do agree...

I'm not at all trying to bad-mouth Sound Professionals, but you know I asked Chris (Sound Pro Chris) a bunch of questions and got *completely* different answers from what other technical minded people on here told me.

Here is the problem with the A-T mics as I see it.. Number 1 the distortion figures they are using are not accurate.. These mics do distort badly I have measured them at 114db at 1k these mics have a distortion that is almost 15% that is VERY HIGH! I measure my own mic capsules from the factory they are 10% typical but after my mod the AT mics measure 0.5% and my mics measure 0.5%. So getting the mod done to these mics saves them from distortion but you do sacrifice some level that's why after doing the mod you should invest in a preamp.. To run your mics unless your always taping loud shows then you don't need a preamp in most cases..

Chris Church

I find people that are using the MT do need a preamp after my mod because the noise floor in the MT preamp is bad to begin with. And when you need the extra gain from the MT it brings up the noise floor too much, that being said the preamp in the Edirol R-09 is much better and more often then not for most loud shows not needed..

Hey Chris.  I think the problem is AT mics were *never* designed to run as "two-wire" at all.  If you look at any of the numerous AT powering options, they use a three-wire circuit.  Even the power modules that are battery/phantom split the battery voltage so that half is across the FET and half across the (source) load resistor.

As far as "not enough gain" that is subjective.  Sure, if you're trying to run into a NJB3 or Iriver, you've got a problem.  But several line inputs, like Edirol R01/R09, and Minidisc have enough gain to bring this up nicely for any amplified music.  I think they might add 10-15dB or so but that is quite enough.  That is why I've been using my MD so much even though I've got a lot (!) of other gear.

  Richard

Richard they are not really three wire capsule all they are is two wire capsules that have a separate ground wire to the case. The red wire is the signal the Yellow is the negative if you remove the ground wire the mic will still work but will be noisy in a true three wire capsule it will not work..

This is the same as the other capsule I use for my mics. I could be wrong but that's what I have discovered.

I gotta disagree with you there!

AT and yours are both three wire.  Red is the drain of the FET, Yellow is the source of the FET and shield is ground (of the capsule).  The other end of the capsule goes to the gate of the FET.  For two wire you short yellow and ground (at the 3.5mm stereo plug, usually).

Your mics have three wires too, +, audio, and ground.  Some variants have a source resistor (eg., 2.2k) soldered between audio and ground.

  Richard

Ok I stand corrected I have never opened up an AT mic.

BTW, there may be a small # of mics (Sennheiser MKE2, some varieties) that have the FET source and ground shorted *at the mic end*.  These cannot be hacked for three-wire use.  Sennheiser MKE-2-4 are shorted this way, MKE-2-5 are not.  I bought the latter after a long search on Ebay.

  Richard

[nameloc01]

i am soo pissed off right now i cant even explain it......

so what is a better option in your guys' opinions??
 the mic mod?
 or the 3 wire BB?

either way .. where to get it/them done??

Mr.Church.. is this something you can do reasonable quick??
thanks

[hawghunter]

yeah, i feel your pain. i think chris can help us out.

[justink]

posted this in another thread...

I run (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-CMC-4U) w/ the stereo 1/8" male.

I then use a stereo [1/8" female to 1/8" male] 20' footer i got from radioshack to go down the stand.

Take the male end of that cable into these phantom adapters (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-XLRM-MINI-2) XLR Male into the UA-5 that gives 48v phantom to the AT's on top of the stand.

works like a charm and sounds great!  about to send the UA-5 off for the Bman tinkering.

HAVE NOT yet tried to run these on the SP batt box... might save that for a shitty local band.

-j

[OOK]

"What I don't understand is why SoundPros have not caught on and offered three wire battery boxes.  They are missing a *huge* market here."

They Do, I had one made probably 7 years ago atleast by Soundpro, probably one of their first.  Each mic is terminated with a 1/8"  miniTRS, they plug into a preamp/batt box that soundpro designed for this purpose.  It has a single stereo control to adjust volume and a toggle switch to turn it on and off. He was selling them for a while at 199.00 but I guess he stopped because of a lack of interest.  I have the 853's and had this problem, once soundpro built the box and reterminated my mics they'd worked great.  11 row at The Who at Hershey PA in front of 11 foot high subs convinved me of that.

[Church-Audio]

What I don't understand is why SoundPros have not caught on and offered three wire battery boxes.  They are missing a *huge* market here.

They'll just tell you need phantom power. 
But I *really* do agree...

I'm not at all trying to bad-mouth Sound Professionals, but you know I asked Chris (Sound Pro Chris) a bunch of questions and got *completely* different answers from what other technical minded people on here told me.

Here is the problem with the A-T mics as I see it.. Number 1 the distortion figures they are using are not accurate.. These mics do distort badly I have measured them at 114db at 1k these mics have a distortion that is almost 15% that is VERY HIGH! I measure my own mic capsules from the factory they are 10% typical but after my mod the AT mics measure 0.5% and my mics measure 0.5%. So getting the mod done to these mics saves them from distortion but you do sacrifice some level that's why after doing the mod you should invest in a preamp.. To run your mics unless your always taping loud shows then you don't need a preamp in most cases..

Chris Church

I find people that are using the MT do need a preamp after my mod because the noise floor in the MT preamp is bad to begin with. And when you need the extra gain from the MT it brings up the noise floor too much, that being said the preamp in the Edirol R-09 is much better and more often then not for most loud shows not needed..

Hey Chris.  I think the problem is AT mics were *never* designed to run as "two-wire" at all.  If you look at any of the numerous AT powering options, they use a three-wire circuit.  Even the power modules that are battery/phantom split the battery voltage so that half is across the FET and half across the (source) load resistor.

As far as "not enough gain" that is subjective.  Sure, if you're trying to run into a NJB3 or Iriver, you've got a problem.  But several line inputs, like Edirol R01/R09, and Minidisc have enough gain to bring this up nicely for any amplified music.  I think they might add 10-15dB or so but that is quite enough.  That is why I've been using my MD so much even though I've got a lot (!) of other gear.

  Richard

Richard they are not really three wire capsule all they are is two wire capsules that have a separate ground wire to the case. The red wire is the signal the Yellow is the negative if you remove the ground wire the mic will still work but will be noisy in a true three wire capsule it will not work..

This is the same as the other capsule I use for my mics. I could be wrong but that's what I have discovered.

I gotta disagree with you there!

AT and yours are both three wire.  Red is the drain of the FET, Yellow is the source of the FET and shield is ground (of the capsule).  The other end of the capsule goes to the gate of the FET.  For two wire you short yellow and ground (at the 3.5mm stereo plug, usually).

Your mics have three wires too, +, audio, and ground.  Some variants have a source resistor (eg., 2.2k) soldered between audio and ground.

  Richard

Ok I stand corrected I have never opened up an AT mic.

BTW, there may be a small # of mics (Sennheiser MKE2, some varieties) that have the FET source and ground shorted *at the mic end*.  These cannot be hacked for three-wire use.  Sennheiser MKE-2-4 are shorted this way, MKE-2-5 are not.  I bought the latter after a long search on Ebay.

  Richard

Hi Richard these are my tests for distortion/output loss my 2 wire mod vrs Normal 3 wire

The red spike indicates distortion of the typical 3 wire battery box.. It is 0.5% at -25db with a 114db extremely low distortion acoustic signal directly coupled to the capsule... The blue spike is the distortion of my 2 wire mod via the 4.7k resistor it shows a loss of 5db over 3 wire..... But the distortion is exactly the same 0.5% here is a picture of both graphs super imposed.


Ps... Notice the third harmonic is gone with my 4.7 k mod strange I don't know why its not there anymore maybe because its 5 db down... I thought you might be interested in the test results.
The AT 853 performs exactly the same way after the mod.. as my capsule does distortion wise.. The thing that concerns me is there are different distortion rates for different capsules of the same make and model so when I match my capsules I use Frequency response distortion % and output in db at 1k as a means of making sure they are the same... I have measured a pair of AT capsules I have here that are in for my modification the difference in distortion between the two supposedly "matched capsules" was 3% distortion! not very matched IMO.. So one capsule was 0.5% distortion the other capsule was 3.5% distortion this would lead me to believe that the capsules that AT makes are being matched for level not for distortion this means you could get one capsule that will distort much earlier then the other in a stereo pair not good news.

Anyway tell me what you think..
Chris Church

[Church-Audio]

i am soo pissed off right now i cant even explain it......

so what is a better option in your guys' opinions??
 the mic mod?
 or the 3 wire BB?

either way .. where to get it/them done??

Mr.Church.. is this something you can do reasonable quick??
thanks

Turn around time is about 2 weeks for me at this point in time... I can do the mod for you its pretty simple. How are your mics terminated now?

[poorlyconditioned]

What I don't understand is why SoundPros have not caught on and offered three wire battery boxes.  They are missing a *huge* market here.

They'll just tell you need phantom power. 
But I *really* do agree...

I'm not at all trying to bad-mouth Sound Professionals, but you know I asked Chris (Sound Pro Chris) a bunch of questions and got *completely* different answers from what other technical minded people on here told me.

Here is the problem with the A-T mics as I see it.. Number 1 the distortion figures they are using are not accurate.. These mics do distort badly I have measured them at 114db at 1k these mics have a distortion that is almost 15% that is VERY HIGH! I measure my own mic capsules from the factory they are 10% typical but after my mod the AT mics measure 0.5% and my mics measure 0.5%. So getting the mod done to these mics saves them from distortion but you do sacrifice some level that's why after doing the mod you should invest in a preamp.. To run your mics unless your always taping loud shows then you don't need a preamp in most cases..

Chris Church

I find people that are using the MT do need a preamp after my mod because the noise floor in the MT preamp is bad to begin with. And when you need the extra gain from the MT it brings up the noise floor too much, that being said the preamp in the Edirol R-09 is much better and more often then not for most loud shows not needed..

Hey Chris.  I think the problem is AT mics were *never* designed to run as "two-wire" at all.  If you look at any of the numerous AT powering options, they use a three-wire circuit.  Even the power modules that are battery/phantom split the battery voltage so that half is across the FET and half across the (source) load resistor.

As far as "not enough gain" that is subjective.  Sure, if you're trying to run into a NJB3 or Iriver, you've got a problem.  But several line inputs, like Edirol R01/R09, and Minidisc have enough gain to bring this up nicely for any amplified music.  I think they might add 10-15dB or so but that is quite enough.  That is why I've been using my MD so much even though I've got a lot (!) of other gear.

  Richard

Richard they are not really three wire capsule all they are is two wire capsules that have a separate ground wire to the case. The red wire is the signal the Yellow is the negative if you remove the ground wire the mic will still work but will be noisy in a true three wire capsule it will not work..

This is the same as the other capsule I use for my mics. I could be wrong but that's what I have discovered.

I gotta disagree with you there!

AT and yours are both three wire.  Red is the drain of the FET, Yellow is the source of the FET and shield is ground (of the capsule).  The other end of the capsule goes to the gate of the FET.  For two wire you short yellow and ground (at the 3.5mm stereo plug, usually).

Your mics have three wires too, +, audio, and ground.  Some variants have a source resistor (eg., 2.2k) soldered between audio and ground.

  Richard

Ok I stand corrected I have never opened up an AT mic.

BTW, there may be a small # of mics (Sennheiser MKE2, some varieties) that have the FET source and ground shorted *at the mic end*.  These cannot be hacked for three-wire use.  Sennheiser MKE-2-4 are shorted this way, MKE-2-5 are not.  I bought the latter after a long search on Ebay.

  Richard

Hi Richard these are my tests for distortion/output loss my 2 wire mod vrs Normal 3 wire

The red spike indicates distortion of the typical 3 wire battery box.. It is 0.5% at -25db with a 114db extremely low distortion acoustic signal directly coupled to the capsule... The blue spike is the distortion of my 2 wire mod via the 4.7k resistor it shows a loss of 5db over 3 wire..... But the distortion is exactly the same 0.5% here is a picture of both graphs super imposed.


Ps... Notice the third harmonic is gone with my 4.7 k mod strange I don't know why its not there anymore maybe because its 5 db down... I thought you might be interested in the test results.
The AT 853 performs exactly the same way after the mod.. as my capsule does distortion wise.. The thing that concerns me is there are different distortion rates for different capsules of the same make and model so when I match my capsules I use Frequency response distortion % and output in db at 1k as a means of making sure they are the same... I have measured a pair of AT capsules I have here that are in for my modification the difference in distortion between the two supposedly "matched capsules" was 3% distortion! not very matched IMO.. So one capsule was 0.5% distortion the other capsule was 3.5% distortion this would lead me to believe that the capsules that AT makes are being matched for level not for distortion this means you could get one capsule that will distort much earlier then the other in a stereo pair not good news.

Anyway tell me what you think..
Chris Church

Thanks.  Very nice analysis.  I would be interested in seeing a two-wire (unmodded) setup here too.  That would be a good advertisement for your gear.  Or at least how *not* to power microphones.

  Richard

[Alchemy]

If this a stupid question, then apologizies in advance, but why does the distortion attack 1k the most?

[poorlyconditioned]

If this a stupid question, then apologizies in advance, but why does the distortion attack 1k the most?

Distortion does not "attack" any one frequency.  1k was just chosen for the test.  What you do is put a 1k tone in (eg., through a loudspeaker) and measure the mic output (through a preamp/ADC step and into the computer).  If all was working you would see only 1k on the output.  But instead you often see *multiples* of the input (2k, 3k, etc) which are called "harmonics".  Hence the term "total harmonic distortion".  These should not be there, but are caused by nonlinearities in the response of the mic (well, the whole signal chain, actually).  You measure the distortion by comparing the desired peak (1k) to undesired ones.  Here you have (in red, I think) the main peak at (approx) -28dB and the 2k peak at -73dB.  The difference is approx 45dB.  So the distortion is 45dB below the signal.  20dB is a factor of ten (in power) so you've got, less than 1% distortion.  1% would be exactly 40dB down.

Bye...

  Richard

[Alchemy]

If this a stupid question, then apologizies in advance, but why does the distortion attack 1k the most?

Distortion does not "attack" any one frequency.  1k was just chosen for the test.  What you do is put a 1k tone in (eg., through a loudspeaker) and measure the mic output (through a preamp/ADC step and into the computer).  If all was working you would see only 1k on the output.  But instead you often see *multiples* of the input (2k, 3k, etc) which are called "harmonics".  Hence the term "total harmonic distortion".  These should not be there, but are caused by nonlinearities in the response of the mic (well, the whole signal chain, actually).  You measure the distortion by comparing the desired peak (1k) to undesired ones.  Here you have (in red, I think) the main peak at (approx) -28dB and the 2k peak at -73dB.  The difference is approx 45dB.  So the distortion is 45dB below the signal.  20dB is a factor of ten (in power) so you've got, less than 1% distortion.  1% would be exactly 40dB down.

Bye...

  Richard

Wow, thank you! +T
That's a great explanation...

[Church-Audio]

If this a stupid question, then apologizies in advance, but why does the distortion attack 1k the most?

Distortion does not "attack" any one frequency.  1k was just chosen for the test.  What you do is put a 1k tone in (eg., through a loudspeaker) and measure the mic output (through a preamp/ADC step and into the computer).  If all was working you would see only 1k on the output.  But instead you often see *multiples* of the input (2k, 3k, etc) which are called "harmonics".  Hence the term "total harmonic distortion".  These should not be there, but are caused by nonlinearities in the response of the mic (well, the whole signal chain, actually).  You measure the distortion by comparing the desired peak (1k) to undesired ones.  Here you have (in red, I think) the main peak at (approx) -28dB and the 2k peak at -73dB.  The difference is approx 45dB.  So the distortion is 45dB below the signal.  20dB is a factor of ten (in power) so you've got, less than 1% distortion.  1% would be exactly 40dB down.

Bye...

  Richard

Wow, thank you! +T
That's a great explanation...

1k is also the standard test frequency. We all know that mics usually don't distort at high frequencies they distort  at low frequencies but its very hard to find a source ( speaker ) that puts out say 40hz with no distortion at 114db so that's why the industry standard is 1k. I think it should be 60hz 150hz and 1k and 10k and 20k because that gives you a picture of the performance of the mic the real problem is finding a speaker that has no distortion at these frequencies. That is very hard. I think its important when your producing mics to know what your distortion figures are so that when I sell a pair of mics they are matched both in distortion performance and total output is matched to with in 0.3db of each other and distortion matching is to with in 0.03% of each mic in a stereo pair.. So when your mics overload they both overload at the same time. If this is not done you could have you left side distort much earlier then the right side.

[poorlyconditioned]

If this a stupid question, then apologizies in advance, but why does the distortion attack 1k the most?

Distortion does not "attack" any one frequency.  1k was just chosen for the test.  What you do is put a 1k tone in (eg., through a loudspeaker) and measure the mic output (through a preamp/ADC step and into the computer).  If all was working you would see only 1k on the output.  But instead you often see *multiples* of the input (2k, 3k, etc) which are called "harmonics".  Hence the term "total harmonic distortion".  These should not be there, but are caused by nonlinearities in the response of the mic (well, the whole signal chain, actually).  You measure the distortion by comparing the desired peak (1k) to undesired ones.  Here you have (in red, I think) the main peak at (approx) -28dB and the 2k peak at -73dB.  The difference is approx 45dB.  So the distortion is 45dB below the signal.  20dB is a factor of ten (in power) so you've got, less than 1% distortion.  1% would be exactly 40dB down.

Bye...

  Richard

Wow, thank you! +T
That's a great explanation...

1k is also the standard test frequency. We all know that mics usually don't distort at high frequencies they distort  at low frequencies but its very hard to find a source ( speaker ) that puts out say 40hz with no distortion at 114db so that's why the industry standard is 1k. I think it should be 60hz 150hz and 1k and 10k and 20k because that gives you a picture of the performance of the mic the real problem is finding a speaker that has no distortion at these frequencies. That is very hard. I think its important when your producing mics to know what your distortion figures are so that when I sell a pair of mics they are matched both in distortion performance and total output is matched to with in 0.3db of each other and distortion matching is to with in 0.03% of each mic in a stereo pair.. So when your mics overload they both overload at the same time. If this is not done you could have you left side distort much earlier then the right side.

Yeah, thanks Chris for all this geek speek!

  Richard