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Gear / Technical Help => Microphones & Setup => Topic started by: F.O.Bean on January 29, 2011, 06:35:56 PM

Title: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on January 29, 2011, 06:35:56 PM
Hello all, since I am getting a Naiant LittleBox>R09, I was wondering if I could just get a pair of mic splitters and run:

MBHO>722
MBHO>LB>R09 ???

Would I use PHANTOM on BOTH the 722 AND the LB, or would I need to run like a PS-2 in front of the 722 and LB and THEN give a signal to my 722 AND LB ??? The LB doesnt have a Line-In so thats where my problem lies, that is, if I cant just run PHANTOM on BOTH the 722 AND the LB ???

TIA,
Bean
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: page on January 29, 2011, 06:47:08 PM
Hello all, since I am getting a Naiant LittleBox>R09, I was wondering if I could just get a pair of mic splitters and run:

MBHO>722
MBHO>LB>R09 ???

Would I use PHANTOM on BOTH the 722 AND the LB, or would I need to run like a PS-2 in front of the 722 and LB and THEN give a signal to my 722 AND LB ??? The LB doesnt have a Line-In so thats where my problem lies, that is, if I cant just run PHANTOM on BOTH the 722 AND the LB ???

TIA,
Bean

if I remember correctly, it's run it on one or the other but not both. While it's better to isolate them (via the PS2), it's possible to have 2 units on the same circuit with just one sending a P48 signal.

If you can't turn the P48 off on the littlebox, then do it on your 722. If I remember correctly, there was a discussion about this in the 7 series team thread, boojum and notlance might remember better then me.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on January 29, 2011, 06:55:23 PM
Hello all, since I am getting a Naiant LittleBox>R09, I was wondering if I could just get a pair of mic splitters and run:

MBHO>722
MBHO>LB>R09 ???

Would I use PHANTOM on BOTH the 722 AND the LB, or would I need to run like a PS-2 in front of the 722 and LB and THEN give a signal to my 722 AND LB ??? The LB doesnt have a Line-In so thats where my problem lies, that is, if I cant just run PHANTOM on BOTH the 722 AND the LB ???

TIA,
Bean

if I remember correctly, it's run it on one or the other but not both. While it's better to isolate them (via the PS2), it's possible to have 2 units on the same circuit with just one sending a P48 signal.

If you can't turn the P48 off on the littlebox, then do it on your 722. If I remember correctly, there was a discussion about this in the 7 series team thread, boojum and notlance might remember better then me.

OK cool, thanks Page :)
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: datbrad on January 30, 2011, 03:53:37 PM
I am not positive, but I think you could be opening yourself up to issues with such a split.

The only mic splitting method I know that works 100% without any risk to the equipment is using a phantom only supply, such as a Denecke PS-2 (http://www.bhphotovideo.com/c/product/406897-REG/Denecke_PS_2_PS_2_Portable_Dual.html) between the mics and the recorders/preamps.

You would split the signal at the output of the phantom supply, properly isolating the voltage beween it and the mics.

You would then only be splitting the mic level signal that carries no other voltage to the LB with phantom off, and to the 722 also with phantom off.

If it were me, that is the only way I would try such a thing.....
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: ghellquist on January 30, 2011, 05:16:27 PM
I´ve used simple Y-connectors often enough without any problems. The circuits in both the mic and the preamp boxes can handle this situation.
As a general precaution I would have phantom power turned on for only one of the boxes, the mics might get a little too high voltage for comfort ( not necessarily a problem, but why take chance it ) .
There are some situation where you might end up with ground loops, but given that these are two recording boxes and will most probably run on batterys I would not expect any issues.
You might possibly find that the small Led-lamp indicating phantom on will light up on the box where phantom is off, don´t worry about that ( I have seen it happen, it has a simple explanation in how the circuits are designed ) .

So, from my experience, go ahead.

// Gunnar
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Church-Audio on January 31, 2011, 03:07:27 AM
Hello all, since I am getting a Naiant LittleBox>R09, I was wondering if I could just get a pair of mic splitters and run:

MBHO>722
MBHO>LB>R09 ???

Would I use PHANTOM on BOTH the 722 AND the LB, or would I need to run like a PS-2 in front of the 722 and LB and THEN give a signal to my 722 AND LB ??? The LB doesnt have a Line-In so thats where my problem lies, that is, if I cant just run PHANTOM on BOTH the 722 AND the LB ???

TIA,
Bean

When ever you run two preamps from one set of mics you risk loading down the mics.. And changing the frequency response of the mic. Its best to use an active splitter or a set of transformers, And get phantom from the hard wired side of the split meaning the side that is directly connected to the mics. This is the whole reason why we use active or transformer splits in pro audio. I personally have heard the effects of two preamps  loading down a single condenser mic I dont like hard wired mic splits for this reason. In some cases its not an issue. But its better to do it properly then to ruin a good recording.

This box works well and actually has a good quality transformer inside it.

http://cgi.ebay.com/PRO-CO-MS-2-Mic-Splitter-Microphone-1-Mic-into-2-Mixers-/360338603678?pt=LH_DefaultDomain_0&hash=item53e5dabe9e#ht_3803wt_938

The best ones are made by BSS for active or Radial for passive transformer based splits

These guys also made a great splitter and used Jensen transformers. I am not 100% that this one has jensens in it but it would be a good bet. these look like NOS or New old stock product. $35 each is dirt cheap.

http://cgi.ebay.com/SESCOM-PO-25-1X3-MICROPHONE-SPLITTER-/330521356561?pt=LH_DefaultDomain_0&hash=item4cf49ba911#ht_1338wt_1114
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: ghellquist on January 31, 2011, 04:42:22 PM
When ever you run two preamps from one set of mics you risk loading down the mics.. And changing the frequency response of the mic. Its best to use an active splitter or a set of transformers,
As a general rule, yes do use splitters. But a transformer splitters works exactly as a Y-cable when it comes to loading the mic. There is no difference in loading when you use 1:1 transformer splitters. The load is the exactly the same as if you use Y-cables. The load is transferred through the transformer to the mic side unchanged. The reason for using transformer splitters is to avoid ground loops and to isolate the sides from each other. Active splitters are a different thing.

Most modern transformerfree condensor mics and modern dynamic mics has an output impedance on the order of 150 Ohms, and can easily take several parallell loads of the typical preamps that has an input impedance often around 2000 Ohms.  On a large stage you can have 3 or 4 splits on the same mic, without problems and using transformer splitters.

Condensor mics with transformers in them might behave differently, and may be quite sensitive to load impedance, but for those a transformer splitter will behave exactly the same as a simply Y-cable.
Band mics ( ribbons ) are known to be quite sensitive to load impedance and should as general rule not be splitted to two preamps ( possible exceptions might be mics like the Royer SF24 that has built in head-amp ) .

// Gunnar
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on January 31, 2011, 05:30:01 PM
See, I could run mics>PS2>722
                       mics>PS2>LB>R09

But how would I turn the phantom off w/ the LB ??? Just leave it on the OFF position or would that just turn off the LB ??? Im confused ???
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Church-Audio on January 31, 2011, 08:37:28 PM
When ever you run two preamps from one set of mics you risk loading down the mics.. And changing the frequency response of the mic. Its best to use an active splitter or a set of transformers,
As a general rule, yes do use splitters. But a transformer splitters works exactly as a Y-cable when it comes to loading the mic. There is no difference in loading when you use 1:1 transformer splitters. The load is the exactly the same as if you use Y-cables. The load is transferred through the transformer to the mic side unchanged. The reason for using transformer splitters is to avoid ground loops and to isolate the sides from each other. Active splitters are a different thing.

Most modern transformerfree condensor mics and modern dynamic mics has an output impedance on the order of 150 Ohms, and can easily take several parallell loads of the typical preamps that has an input impedance often around 2000 Ohms.  On a large stage you can have 3 or 4 splits on the same mic, without problems and using transformer splitters.

Condensor mics with transformers in them might behave differently, and may be quite sensitive to load impedance, but for those a transformer splitter will behave exactly the same as a simply Y-cable.
Band mics ( ribbons ) are known to be quite sensitive to load impedance and should as general rule not be splitted to two preamps ( possible exceptions might be mics like the Royer SF24 that has built in head-amp ) .

// Gunnar
Theory is great. I have had 20 years experience as a live sound engineer and in that time I have found that under some circumstances I have had issues with two preamps and one condenser mic. Quite simply an adverse affect on frequency response of a condenser microphone. Connected with a Y cable. The best solution would be to use a three way transformer or an active split providing the electronics in question dont degrade the signal. I think you could test the Y cable and confirm there are no issues and maybe with the gear being used there will be none. I dont know all I know is I have had issues in the past with this. Mind you one side of the split was 150 to 250 feet away from the other preamp.

Chris
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: ArchivalAudio on January 31, 2011, 09:55:46 PM
See, I could run mics>PS2>722
                       mics>PS2>LB>R09

But how would I turn the phantom off w/ the LB ??? Just leave it on the OFF position or would that just turn off the LB ??? Im confused ???
Bean,
Your LB would need this option:
Quote
Microphone power on/off toggle switch, $10
so you could turn off the phantom on the LB
if you did not order it that way, you perhaps could send it back to Jon for the mod/option.

--Ian
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: page on January 31, 2011, 09:59:22 PM
Sound Devices votes for a tranny split (http://twitter.com/sounddevices/status/32204370237984768) on the issue.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: SmokinJoe on February 01, 2011, 01:07:23 PM
For a while I tried my Earthworks hypers Z30XL running into my R4, with simple Y splits to the Tmod and Vmod channels.  I noticed that it didn't sound quite as sweet when I ran that way as when I ran into just one.  It reduced the low end, and on those things the last thing you wanted was more bass rolloff.  I've done it with other mics and it didn't seem to make much difference.  So, I think Chris is right... sometimes it matters, I can't tell you which mics are more fussy about it than others.    We tend to say "if the plug fits it must be good", but that's not always so.  You ever notice those higher end studio pre's with the adjustable impedance?  I don't think that's just a gimmick, I think matching impedance can matter... which is probably the cause for a lot of the anecdotal opinions of "these mics sound sweet with this pre".

In Bean's case... try it using cheap Y splits, use the phantom from the LB if it's always on, and turn off the power on the SD.  If it works great, so be it.  If it seems sub-optimal, chalk it up to experience and try something else.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: ArchivalAudio on February 01, 2011, 02:28:00 PM

In Bean's case... try it using cheap Y splits, use the phantom from the LB if it's always on, and turn off the power on the SD.  If it works great, so be it.  If it seems sub-optimal, chalk it up to experience and try something else.
in theory if you put the Y on the mics and sent phantom through them it would also be sending Phantom to the SD which might not have great long term results.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Church-Audio on February 01, 2011, 02:49:05 PM

In Bean's case... try it using cheap Y splits, use the phantom from the LB if it's always on, and turn off the power on the SD.  If it works great, so be it.  If it seems sub-optimal, chalk it up to experience and try something else.
in theory if you put the Y on the mics and sent phantom through them it would also be sending Phantom to the SD which might not have great long term results.

There should be no issue what so ever with phantom.. If both products are properly designed.
I would personally be more concerned about frequency response issues than phantom :)
Chris
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: it-goes-to-eleven on February 01, 2011, 03:14:22 PM
I have also experienced diminished microphone performance when using splitters, and no longer use them.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Church-Audio on February 01, 2011, 04:12:25 PM
I have also experienced diminished microphone performance when using splitters, and no longer use them.

Y cables or real splitters?

Chris
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 01, 2011, 04:33:08 PM
Thanks for the info and disscution about this. I guess I will get a PS2 and run the split after that. Now to run the LB>R09, Ill just have to get a new pair of mics ;D Quitting smoking is going to allow me to buy whatever I want and save 300/month on cigs ;D
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: it-goes-to-eleven on February 01, 2011, 04:43:52 PM
Y cables or real splitters?

Y cables.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Church-Audio on February 01, 2011, 04:59:22 PM
Y cables or real splitters?

Y cables.

I think the main thing to come away with here is there are variables like what preamps and what mics you will be using.. Sometimes you can get away with it sometimes not.. In a case like this I say its better to spend the extra cash and get something that will do the job. If you have the ability to really evaluate the changes going on in an objective manor then you can always try a Y cable..
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 01, 2011, 05:08:51 PM
o what do you consider "safe" ??? Getting a PS2 and splitting the signal after the PS2. Or getting those mic splitter boxes and doing the split that way ???
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Todd R on February 01, 2011, 11:39:33 PM
Y cables or real splitters?

Y cables.

I think the main thing to come away with here is there are variables like what preamps and what mics you will be using.. Sometimes you can get away with it sometimes not.. In a case like this I say its better to spend the extra cash and get something that will do the job. If you have the ability to really evaluate the changes going on in an objective manor then you can always try a Y cable..

Yeah, this has me curious to learn more from the people who have noticed a difference to see if there are any commonalities -- eg, transformer mics or not, perhaps electret or not, high or medium impedence recorders, split mics into preamps or recorders, did the split mics go into two different preamps and/or recorders that might have different input impedences or did they go into a single 4ch or multichannel recorder, etc.

I think I have only split a mic signal once or twice (more often have split a soundboard signal into multiple recorders, or split a line-level preamp signal into multiple recorders).  I don't remember hearing a difference or noticing something off, but the effect may have been there and I hadn't noticed it.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: ArchivalAudio on February 02, 2011, 01:41:11 AM
Y cables or real splitters?

Y cables.

I think the main thing to come away with here is there are variables like what preamps and what mics you will be using.. Sometimes you can get away with it sometimes not.. In a case like this I say its better to spend the extra cash and get something that will do the job. If you have the ability to really evaluate the changes going on in an objective manor then you can always try a Y cable..

Yeah, this has me curious to learn more from the people who have noticed a difference to see if there are any commonalities -- eg, transformer mics or not, perhaps electret or not, high or medium impedence recorders, split mics into preamps or recorders, did the split mics go into two different preamps and/or recorders that might have different input impedences or did they go into a single 4ch or multichannel recorder, etc.

I think I have only split a mic signal once or twice (more often have split a soundboard signal into multiple recorders, or split a line-level preamp signal into multiple recorders).  I don't remember hearing a difference or noticing something off, but the effect may have been there and I hadn't noticed it.
I agree it seem to me that there is no degradation using an XLR  Y splitter on a soundboard feed, but may be I am wrong?
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Church-Audio on February 02, 2011, 01:46:36 AM
Y cables or real splitters?

Y cables.

I think the main thing to come away with here is there are variables like what preamps and what mics you will be using.. Sometimes you can get away with it sometimes not.. In a case like this I say its better to spend the extra cash and get something that will do the job. If you have the ability to really evaluate the changes going on in an objective manor then you can always try a Y cable..

Yeah, this has me curious to learn more from the people who have noticed a difference to see if there are any commonalities -- eg, transformer mics or not, perhaps electret or not, high or medium impedence recorders, split mics into preamps or recorders, did the split mics go into two different preamps and/or recorders that might have different input impedences or did they go into a single 4ch or multichannel recorder, etc.

I think I have only split a mic signal once or twice (more often have split a soundboard signal into multiple recorders, or split a line-level preamp signal into multiple recorders).  I don't remember hearing a difference or noticing something off, but the effect may have been there and I hadn't noticed it.
I agree it seem to me that there is no degradation using an XLR  Y splitter on a soundboard feed, but may be I am wrong?

Sound board feed is different than a mic split.. I have 100% for sure heard the difference the first time I heard it I had to do the show with no kick drum in the monitor because it degraded the signal so badly.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: Chuck on February 02, 2011, 09:49:14 AM
It probably would not be too difficult to build an active splitter using op-amps and a 9v battery.
I made a couple of active direct boxes once for use in sound reinforcement using TL072's.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 03, 2011, 05:21:34 PM
So, PS2>splitters>preamps or Mic Splitters boxes>preamps or Y cable ???
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 23, 2011, 10:47:50 PM
So, PS2>splitters>preamps or Mic Splitters boxes>preamps or Y cable ???

What do yinz suggest ???
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 23, 2011, 10:52:46 PM
Oh and my LB got modded so I can turn Phantom ON/OFF
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: TNJazz on February 24, 2011, 10:35:02 AM
start with simple Y cables

I seriously doubt you'll notice much difference in mic performance if the cables are good quality and wired properly

If it doesn't work, then add a PS-2.  You'll still need the Y cables anyway, so there's no reason not to try the simplest solution and work up from there.

Phantom on from one box, off from the other.
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 24, 2011, 05:44:27 PM
littlebox's input impedance goes high with phantom off, so it won't load the mic hardly any at all.  With phantom on, it's still only 4K.  If all gear is battery powered, I would use a Y-cable.

start with simple Y cables

I seriously doubt you'll notice much difference in mic performance if the cables are good quality and wired properly

If it doesn't work, then add a PS-2.  You'll still need the Y cables anyway, so there's no reason not to try the simplest solution and work up from there.

Phantom on from one box, off from the other.

Thanks for the info guys. Looks like I'm going to try it ;D
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: page on February 24, 2011, 10:11:27 PM

Thanks for the info guys. Looks like I'm going to try it ;D

Do you need cables or do you already have Y cables? (I have some)
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 24, 2011, 10:36:11 PM

Thanks for the info guys. Looks like I'm going to try it ;D

Do you need cables or do you already have Y cables? (I have some)

Page, I need to buy them. I have someone willing to make me a pair, but maybe I could try them out first w/ your cables before I buy a pair ???
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: page on February 24, 2011, 10:38:46 PM

Thanks for the info guys. Looks like I'm going to try it ;D

Do you need cables or do you already have Y cables? (I have some)

Page, I need to buy them. I have someone willing to make me a pair, but maybe I could try them out first w/ your cables before I buy a pair ???

I have a set that Rob made me, PM sent
Title: Re: Splitting a mic signal PHANTOM questions.......
Post by: F.O.Bean on February 24, 2011, 10:44:54 PM

Thanks for the info guys. Looks like I'm going to try it ;D

Do you need cables or do you already have Y cables? (I have some)

Page, I need to buy them. I have someone willing to make me a pair, but maybe I could try them out first w/ your cables before I buy a pair ???

I have a set that Rob made me, PM sent

+T Page 8)