Topic: Line Match? Or not?

[skiphunt]

nOOb alert ;-)

I'm using the new ZOOM H2, and running a Sennheiser ME66 into it. Since the ME66 shotgun is mono, I'm using a Shure Line-Matching-Transformer going XLR to 1/8" single line mono plug. However, when recording it's very difficult to control the clipping I get. Even if I run the level down, anything that jumps out of a certain range, even by a little.. seems to clip. It's doable, and I have got decent recordings with this setup... but I tried a regular Mogami XLR to 1/8" stereo mini and there was a noticable difference. First, using the Mogami seemed less sensitive, and less erratic. It also sounded less "bright" and perhaps slightly more "natural". Overall, less sensitive. I'd say, about 5-8 level adjustment clicks difference between using a LMT and the standard Mogami. And, a general difference in sound coloring.

Why is there such a difference? What "should" I be using with this H2? I don't know any of the mic jack specs, and I know this little zoom H2 is probably beneath some of you ;-) but it's doing a swell job for me so far. I just want to make sure I'm using the right cable. I'll also be using a RODE NT3 from time to time.

I'm guessing a stereo 1/8" mini would be a better route to go since that plug just seems to "fit" better than the mono plug. Not sure why. Which mini plug "should" I be using?

Do I really need a LMT? 

Here are a few I was looking at:

http://www.bhphotovideo.com/c/product/423360-REG/Hosa_MIT156_MIT_156_Low_to_High.html

http://www.bhphotovideo.com/c/product/217589-REG/Sennheiser_CL2_CL_2_Transmitter_Line_Cable.html

http://www.bhphotovideo.com/c/product/352326-REG/Audio_Technica_AT8341_XLR_to_Mini_Cable.html

http://www.bhphotovideo.com/c/product/400719-REG/Monster_Cable_125088_iStudioLink_XLR_to_1_8_.html


Would any of these cables make a difference one way or the other?

Any help much appreciated.

[Church-Audio]

nOOb alert ;-)

I'm using the new ZOOM H2, and running a Sennheiser ME66 into it. Since the ME66 shotgun is mono, I'm using a Shure Line-Matching-Transformer going XLR to 1/8" single line mono plug. However, when recording it's very difficult to control the clipping I get. Even if I run the level down, anything that jumps out of a certain range, even by a little.. seems to clip. It's doable, and I have got decent recordings with this setup... but I tried a regular Mogami XLR to 1/8" stereo mini and there was a noticable difference. First, using the Mogami seemed less sensitive, and less erratic. It also sounded less "bright" and perhaps slightly more "natural". Overall, less sensitive. I'd say, about 5-8 level adjustment clicks difference between using a LMT and the standard Mogami. And, a general difference in sound coloring.

Why is there such a difference? What "should" I be using with this H2? I don't know any of the mic jack specs, and I know this little zoom H2 is probably beneath some of you ;-) but it's doing a swell job for me so far. I just want to make sure I'm using the right cable. I'll also be using a RODE NT3 from time to time.

I'm guessing a stereo 1/8" mini would be a better route to go since that plug just seems to "fit" better than the mono plug. Not sure why. Which mini plug "should" I be using?

Do I really need a LMT? 

Here are a few I was looking at:

http://www.bhphotovideo.com/c/product/423360-REG/Hosa_MIT156_MIT_156_Low_to_High.html

http://www.bhphotovideo.com/c/product/217589-REG/Sennheiser_CL2_CL_2_Transmitter_Line_Cable.html

http://www.bhphotovideo.com/c/product/352326-REG/Audio_Technica_AT8341_XLR_to_Mini_Cable.html

http://www.bhphotovideo.com/c/product/400719-REG/Monster_Cable_125088_iStudioLink_XLR_to_1_8_.html


Would any of these cables make a difference one way or the other?

Any help much appreciated.

In order to know if you need a transformer you need to know what the input impedance is of the two devices you want to connect furthermore you need to know what the relative output of the microphone is ( its sensitivity ) it sounds like there are a few things happening here. One - You might need and external preamp for your mic. Two your overloading the preamp input with the proper matching transformer attached Three that your loading down the mic too much with out the transformer.. This often sounds like less top end, when we talk about condenser mics..

So do a bit of homework I suspect your mics is 150 to 300 ohms and your recorder is 10k input impedance so you would need a Low to Hi impedance converter at a 1:1 ratio... so you dont overload your input... But some form of attenuation "might also be needed"

[skiphunt]

Do my homework? I thought that's what I was doing, ie. going to a forum where those who understand all the "spec" talk might be able to school me. I did say this was a "nOOB alert". Are you saying that I must learn what all the Kiloohm, hertz, impedance, etc. means before I can ask a question regarding the best cable to buy?

Looks like the Sennheiser is 200ohms and the H2 is 20K. Are you also saying that for different mics, and different XLR to 1/8" mini cable will need to be used? Doesn't look like there are all that many to choose from. Just wondering if I need the stereo or mone mini plug, and if I really need a LMT or not. Sorry if my understanding of the gear spec terms is not on par with what's required to get cable advise.

[ethan]

So do a bit of homework I suspect your mics is 150 to 300 ohms and your recorder is 10k input impedance so you would need a Low to Hi impedance converter at a 1:1 ratio... so you dont overload your input... But some form of attenuation "might also be needed"

BTW ideally you want the load impedance to be less than or equal to the input impedance. If you go way over on your load impedance relative to the input impediance you you'll get some nasty low end "muddyness".

Also you can think of the difference in load impedance vs. input impedance as gain. If the the load impedance is 10K and the  input impedance is 20K there will be voltage gain between the load and input.

-e

[Church-Audio]

Do my homework? I thought that's what I was doing, ie. going to a forum where those who understand all the "spec" talk might be able to school me. I did say this was a "nOOB alert". Are you saying that I must learn what all the Kiloohm, hertz, impedance, etc. means before I can ask a question regarding the best cable to buy?

Looks like the Sennheiser is 200ohms and the H2 is 20K. Are you also saying that for different mics, and different XLR to 1/8" mini cable will need to be used? Doesn't look like there are all that many to choose from. Just wondering if I need the stereo or mone mini plug, and if I really need a LMT or not. Sorry if my understanding of the gear spec terms is not on par with what's required to get cable advise.

Relax I did not mean any offence by saying "do a bit of homework"..... Anyway you have way to much of a mismatch... I would suggest using some kind of preamp in between these two.. There are plenty of cheap ones around if your application is not so "hifi" what did you want to do with this what are you trying to record?

[skiphunt]

very portable, boomed dialogue for video. It's pretty close as it is. Just wondering.. since there's a significant difference between the Shure LMT with mono mini I already have.. and a Mogami XLR to 1/8" stereo mini... I might need to explore the best cable for my application. Also, some say the 1/8" plug is "TRS?" what does that mean?

Maybe I'll just call b&hphotovideo and see what they recommend. From my experimentation, I'm not convinced I must have a mixer or preamp in the mix yet. I do have a small mixer, but it needs AC power. I'm trying to get this as portable as possible without additional gear to deal with. Might not be possible, but I think with the right cable, and external mic setup.. I can get adequate results for my needs. There are just too many compatibility terms I simply don't understand well enough to figure it out for myself. I thought I might fair better from this forum.

[ethan]

...I'm not convinced I must have a mixer or preamp in the mix yet.

It won't take long. Pre's are a must.

[skiphunt]

Well, I'm trying to keep this as portable as possible. The Sennheiser is self-powered, is there such a thing as a small pre that's self powered in-line and small?

[skiphunt]

Well, I'm trying to keep this as portable as possible. The Sennheiser is self-powered, is there such a thing as a small pre that's self powered in-line and small?

also, are you saying that there is NO way I can use a self-powered shotgun mic to get good/natural/warm dialogue recordings using ONLY the pres in the Zoom H2?

[skiphunt]

I am confused.  You apparently got good results without the transformer, and with the transformer, you were clipping.  That is because the transformer was giving you voltage gain you didn't need.  Low output impedance into high input impedance is a good thing.

"The difference between load impedance vs. input impedance is gain" No it isn't.  Even if you are using a transformer, it's not the ratio of impedance, but the turns ratio that is gain (or loss).  But for signal transmission, the higher the input impedance goes relative to output impedance, that will reduce loading of the source, and thus loss of signal in the source.  But that isn't a linear equation, once you go beyond a reasonable figure for input impedance, there is little to no change in the signal level.

You don't need a preamp unless you don't have enough gain (or the gain you get is noisy, or you are somehow otherwise unsatisfied) in the H2.  If it ain't broke . . . don't fix it!  And neither the mic nor a preamp would make an impedance mismatch . . . because they both would have roughly the same output impedance!  So the question is, did it sound good to you going straight in, without the transformer?


PS, TRS - tip-ring-sleeve, a reference to a connector with two signal wires plus shield.  The H2's mic input is stereo, with left on tip and right on ring.  It also has a line input, which is similar, but expects a higher signal level.  You would use that connector if you were using an external preamp.

However, your Senn mic is balanced output, with the two conductors being the same signal in opposite polarity (balanced).  If you use an XLR-1/8" TRS cable to connect, you will record the same signal (mono), on both stereo channels, but with each channel in opposite polarity.  This isn't a terrible thing to do if you only need a mono recording; you can combine the two signals after recording by inverting polarity on the right channel and summing (mixing) them; in that way you will have a balanced signal recorded, which helps eliminate transmission line noise.

If you wish to use two mics to record in stereo, then you are looking at a splitter cable.

The sound was good coming from the Mogami, but wasn't quite as "bright" as with the Shure LMT. I also had to get the mic much closer in for a good level, ie. within 2ft. This isn't so swell for a shotgun mic where you need to be out of frame. With the LMT, I could get a good level within about 4-5 feet. However, it was VERY difficult to prevent clipping from the slightest change outside a narrow range. Does that make sense?

[ethan]

"The difference between load impedance vs. input impedance is gain" No it isn't. 

Yes it is the "turns" basically addes resistance.

If you have 10K on the load and attach it to a 20K input you get more voltage on the input than the open circuit load gives you.

A good discustion here: http://sound.westhost.com/impedanc.htm

Scroll down to Impedance Matching

It's interesting when they're talking about why a 600Ohm mic needs a 1.2k-2k input .

-e

[skiphunt]

er... um... I don't understand all of this. Can anyone tell me which cable I likely "should" be using for the best results given the 200ohm rating of the Senn ME66 mic and the 20k input of the H2? Looks like there's about 5-6 varieties of cables I can choose from on bhphotovideo. Just wondering which one is the correctly matched cable.

[Church-Audio]

er... um... I don't understand all of this. Can anyone tell me which cable I likely "should" be using for the best results given the 200ohm rating of the Senn ME66 mic and the 20k input of the H2? Looks like there's about 5-6 varieties of cables I can choose from on bhphotovideo. Just wondering which one is the correctly matched cable.

NO cable will work with that.. get a transformer... 1:1 RATIO low impedance to High or get a preamp..



Ps.. And I dont make a preamp that can do what you need it to do so I am not just giving you this advice to "sell you something"

Chris

[skiphunt]

er... um... I don't understand all of this. Can anyone tell me which cable I likely "should" be using for the best results given the 200ohm rating of the Senn ME66 mic and the 20k input of the H2? Looks like there's about 5-6 varieties of cables I can choose from on bhphotovideo. Just wondering which one is the correctly matched cable.

NO cable will work with that.. get a transformer... 1:1 RATIO low impedance to High or get a preamp..



Ps.. And I dont make a preamp that can do what you need it to do so I am not just giving you this advice to "sell you something"

Chris

The Shure LMT cable I have has this printed on it: Wired for 150 Ohm on low Z side. For 600 Ohm exchange Orange and Yellow wires. On the High Z end (pointed toward the miniplug end) it says 3k Ohm.

The HOSA cable I found on bhphotovideo has the following specs:

ine-Matching Transformer, 600ohm Low-Z to 2500ohm Medium-Z.  Matches microphones with XLR connectors to 3.5mm inputs found on personal portable recording devices, camcorders, and computers.


Should I rewire the Shure? Stick with it? Or get this HOSA cable instead?

thx,

Skip

[Church-Audio]

er... um... I don't understand all of this. Can anyone tell me which cable I likely "should" be using for the best results given the 200ohm rating of the Senn ME66 mic and the 20k input of the H2? Looks like there's about 5-6 varieties of cables I can choose from on bhphotovideo. Just wondering which one is the correctly matched cable.

NO cable will work with that.. get a transformer... 1:1 RATIO low impedance to High or get a preamp..



Ps.. And I dont make a preamp that can do what you need it to do so I am not just giving you this advice to "sell you something"

Chris

The Shure LMT cable I have has this printed on it: Wired for 150 Ohm on low Z side. For 600 Ohm exchange Orange and Yellow wires. On the High Z end (pointed toward the miniplug end) it says 3k Ohm.

The HOSA cable I found on bhphotovideo has the following specs:

ine-Matching Transformer, 600ohm Low-Z to 2500ohm Medium-Z.  Matches microphones with XLR connectors to 3.5mm inputs found on personal portable recording devices, camcorders, and computers.


Should I rewire the Shure? Stick with it? Or get this HOSA cable instead?

thx,

Skip

The SHURE is fine the way it is 150:3k is fine... Now. that should work you might find you need more gain you also need an adaptor to go from the output of the Shure to a stereo 3.5 mm jack both the ring and the tip of the jack must be shorted so you get your audio on both left and right..

Chris