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Why do you want to go split that perfectly good mic anyway? Dynamics Plugins
Old 8th October 2002
  #1
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Remoteness's Avatar
 

Thread Starter
Question Why do you want to go split that perfectly good mic anyway?

What kind of mic splitter do you use?

1 - Non-isolated passive
2 - Isolated passive
3 - Non-isolated active
4 - Isolated active

Do you split the mics and plug into pre's onstage, then go line level back to your rig?

What's your size & flavor?

What kind of bells and whistles does it have?

Here's some of ASL's stuff > Mic / line splitter systems

Want more information about these devices? Post a question to this thread for a reply!
Old 8th October 2002
  #2
Gear maniac
 

depending on you and your gigs - you are probbably most likely to need a few different options.

For me personally, I half the time need to take the split from the stage (along with my own spot and room mics), and the other half just do straight splits at the FOH position.

The key thing I have overlooked in the past is your overall snake system. If you were to have a 48 channel split system, and only need to split 36 channels, you could use the extra channels for your own mics (which would work ideallyl if you were taking the direct side of the split).

I think the cool thing to do is to design a snake system to get signal (splits and your own mics) back your your remote or mobile post, and also have a split system that can interface with your snake system. This way you can bring (or rent) whatever size splitter is needed, and use as many or as little or your own mics as possible. Also, with the snake system taken care of, you can free up your options as to where you run your mic pres, and where to split from. Most times that I would need to split at the FOH, I would need to have a split-box that was like one of the narrow Whirlwind units so that I could tuck behind the console's "dugout", and just let the house's fan plug right into, and then take a multipin>fan into the console - and the other multpin to my snake system...

Steve, could you touch upon some flexible ideas for creating a snake system, and then splitters that can interface with it as one grows?
Old 8th October 2002
  #3
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Jay Kahrs's Avatar
Re: Why do you want to go split that perfectly good mic anyway?

Quote:
Originally posted by Remoteness
What kind of mic splitter do you use?

1 - Non-isolated passive
2 - Isolated passive
3 - Non-isolated active
4 - Isolated active
What's the advantage and disadvantage of each design?
Old 8th October 2002
  #4
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Thread Starter
Re: Re: Why do you want to go split that perfectly good mic anyway?

Quote:
Originally posted by Jay Kahrs


What's the advantage and disadvantage of each design?
Using mic splitters to interface the recording truck, MON and FOH positions is a great idea. There are four ways you can split your mics.

1 - A transformer isolated splitter. A great way to get the job done. The transformer keeps you isolated from everyone else.

2 - A non-transformer splitter. (Y cords in a box) It's the least expensive, but not the smartest way to interface three consoles. Everyone is tied to each other. You could add ground lifts to the outputs, but this does not change the fact you're still tied to each other. Stationary facilities can get away with this, if the system is designed properly and you don't have any outside equipment additions, coming and going like "guest" consoles, etc.

3 - An active splitter with isolated splits. Nice device, because you have the transformer outputs and you have plenty of level to drive your long snake runs. Most active systems help prevent RFI problems too.

4 - An active splitter without isolated splits. Great for running long lines, but still a problem. See # 2 for explanation.

Real transformer isolated splitter systems are popular with many of the professional sound companies out there. Many have them as standard equipment. With some companies, you have to order it for your tour or dates special, just like you would if you needed an isolation transformer for your power. Remember this: All professional remote recording companies have both microphone and AC power isolation transformers.

You can build one yourself, but they are not cheap to build. You can buy them from various sources. BSS, Klark Teknik, Whirlwind, Wireworks, XTA among others, build and sell really nice splitter systems for a price.

With a transformer split, you are totally isolated from the direct signal when you connect to the secondary side of a transformer splitter system. There is no physical connection to the direct signal path. The direct (primary side) mic that feeds the console is the only one that can phantom power the mics. No voltage is present on the secondary side of the transformer. Besides helping eliminate ground loops caused by interfacing different systems, the console or snake connected to the secondary side of the splitter system can be crossed patched and/or totally shorted out (for that matter) without taking down the system or other consoles attached to it.

An isolation transformer splitter system is a great tool when interfacing to various systems like band monitor rigs, multiple desk dates, TV and radio feeds, mobile units and remote flypacks, etc. Pretty important stuff. Keep in mind an isolation transformer will only help ground loop problems created by interfacing different consoles together, not the ones you show up with
Old 8th October 2002
  #5
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Remoteness's Avatar
 

Thread Starter
JC,

The key thing to remember, our snakes are wired with extra tie lines. So even if you are on the transformer side, you still can get mics back to the truck with no phantom power issues. The 40 channel splitter has 12 send/return lines. The 48 channel splitter has 6 to 8 tie lines, depending on whether you're using the 52 or 56 channel snake. The 24 channel XTA splitters are designed to work as two independent systems or can be interfaced to make a 48 channel system. When used as a 24 channel rig, you have 30 to 32 tie lines available, depending on the snake used. Just like you mention, flexibility is key. Virtually any possibility is available with our splitter systems.


Descriptions of our splitter systems & snakes are available at this link > Mic splitters & snakes
Old 9th October 2002
  #6
Gear maniac
 

Steve, how about maintaining the utmost fidelity in a split?

Lets say you are doing a classical gig, and all mics are split between you and a 2nd truck (broadcast or video perhaps)...

You have a few main stereo microphone pairs that are going to be the meat and potatoes of the mix, and possibly the whole mix.

What type of splitter do you reach for, and between the different x-former isolated splits, which x-formers to do you prefer over others for the purist client?
Old 9th October 2002
  #7
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Thread Starter
Jay,

Taking the direct side maintains the utmost fidelity.

Usually, on a classical gig, all the recording mics go directly to the recording truck. When you need to split them, the split happens between live sound and the recording. I guess there may be an additional broadcast or video truck used. In that case you would give them the third split.

We reach for a transformer isolated split and take the direct side of the device. Any good quality transformer will do the job, but I prefer the direct signal over the transformer for the purist client.
Old 19th October 2003
  #8
Gear interested
 

The splitter I made for my truck

I designed and built a splitter for my small remote truck (http://www.curbside-recording.com/). My snakes are 40 pairs and there are 32 isolated splits. The last 8 lines are for our own mics.

Pictures of the splitter are at http://www.curbside-recording.com/hrmusic/splitter.html

I originally thought that we would be using the direct out most of the time and didn't plan a way to bring the last 8 lines into the isolated outputs. I will have to add another db25 connector to allow access to those 8 lines. I was going to just wire the last 8 lines in parallel, but Steve talked me into doing it right at dinner last week (when I was visiting AES).

In case anyone doesn't know this, the reason one doesn't wire mic audio lines (or actually any signal lines running between equipment on different grounds) together without isolation transformers is that there might be large enough differences in ground potential to fry the gear.
Old 19th October 2003
  #9
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Steve Smith's Avatar
 

I will second the method of taking the direct line to the truckj. Whenever I am in Steves trucks I actually insist we do this with the sound company, cause I know that it will be dead quiet. ( not blowing smoke up anyones ass.. but when the an ASL truck rolls in, ground loops run and hide.. it is friggn errily quiet in there ) The other great benefit to having the direct send is that you get to supply 48v to the mics, and for some odd reason, I find the phantom supplied by high end outboard pres and recording consoles to make mics perform better then most mid range FOH consoles.....


Old 19th October 2003
  #10
Gear interested
 

Taking the direct feed

There are many good reasons for not taking the direct. For example:

1. The FOH (or monitor) engineers are insecure about relinquishing control. In this case, it's better to sacrifice for the good vibe of the show (which is way more important that whether you get a direct feed or not).

2. The house engineers are used to their stage box arrangement and it's incompatible with your splitter -- We encountered this at the Hatch Shell in Boston. This is a case of being a good listener regarding how they work before jumping in and trying to change everything. If you see what they are doing, it will be obvious when it's impractical to take the first split.

3. When communication with the house staff is not good for whatever reason (technical or personal).

4. If your schedule requires you to tear down in a hurry and you are just recording an opening act. If you are providing phantom, you have to stay connected until everyone is done. If you are on an isolated split, you can pull the multi-pin and pack up everything except the splitter before the show is over.

At any rate, this is why one doesn't cut corners on the splitter transformers.
Old 19th October 2003
  #11
Gear interested
 

Negotiating for the Direct Feed

You know after reading that last post, I realized that I may not be the best negotiator in this regard. That or maybe I'm dealing with FOH engineers who are less professional than the ones you guys regularly deal with... And of course, what I really want to do is get a rack full of remote mic pres and split off the house after them: With the FOH guys freaking out about losing control over phantom, I can't imagine what they would think about having an actual amplifier in front of their console.

Do you have any negotiating tricks?
Old 20th October 2003
  #12
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bjornson's Avatar
 

I'm also a fan of the "mic pres onstage, record truck take direct, FOH/Mon take transformer split method" because,
1)I take the time to work all this out (in detail!!!!) before hand
2)Good FOH/mon guys know their mic pres suck
3)I also record the opening act(s) set and basically give it away. (good politics)
Most always the foh guy is thrilled at the difference good pres and mics make.
In fact I've NEVER had to argue (at the gig) about these details when they were handled properly up front.
As a former FOH guy, I only got frustrated when i got hit.....
At the last minute, by an @sshole!!!!!!!!!!!
I could always handle one or the other, but sometimes not both grudge
Old 20th October 2003
  #13
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Steve Smith's Avatar
 

There are some really solid tips for "getting your way" on this thread

One of the #1 must have skills for a remote guy to me is the ability to find out who is really in charge and make that person your ally withot making any enemies... If you cant get your way, remember, we are Remote recorders.. it is our job to take it like it comes and make it sound great!
Old 20th October 2003
  #14
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gregrw's Avatar
 

Splitter? I don't need no STEEKIN' splitter!!! I just do FOH, monitors and the recording from the same board.

I realize that the preceding sentence may have scared the living snot out of some of you, but keep in mind that I play in a verrry different league than most of you. Whereas I see that some of you have been to the Hatch Shell and the New Boston Garden, I do stuff at VFWs and small clubs. It's all good, though; ya gotta start somewhere! Besides, it's fun. Wormfest was a blast!

It's funny that this thread appeared now, because I am thinking of taking it to the next level(!), and recording in places like Ralph's and the Lucky Dog in Worcester, MA. For them, I'll need to split mics because there are already consoles in both places. I will be reading this thread more carefully, and looking at the links you all provided (thanks!!) but I just wanted to drop my smart-ass comment. :-)

In the meantime, let's see if I have this straight, concerning the types listed: isolated has a transformer in the audio path, non-isolated is just wires soldered together, active means the signal is boosted (as in a mic pre??) before going down the looooong snake, passive is just copper, isolated is much more expensive than non, active is much more expensive than passive, and isolated active is really really really expensive. Is any of this within the realm of reality?

Thanks, you guys rock!

-GRW
Old 21st October 2003
  #15
Gear Head
 
MJohnson's Avatar
 

On the "Pres On Stage Method - line level to truck" are you talking remote controlled pres?

If not, how do you set the gain for the recording when the pres are on the stage and the recorder is not in the same place?

Forgive my ignorance,


Mark

p.s. Great info in this thread, especially for newbs like me thumbsup
Old 21st October 2003
  #16
Super Moderator
 
Remoteness's Avatar
 

Thread Starter
Quote:
Originally posted by MJohnson
On the "Pres On Stage Method - line level to truck" are you talking remote controlled pres?

If not, how do you set the gain for the recording when the pres are on the stage and the recorder is not in the same place?

Forgive my ignorance,


Mark

p.s. Great info in this thread, especially for newbs like me thumbsup
We do it thee old fashioned way; We have our stage A2 or systems tech twist the knobs.
Old 21st October 2003
  #17
Gear Head
 
MJohnson's Avatar
 

Ah!

My current setup uses #2 isolated passive splitters, rack mounted.

The gigs I record there is not normally a seperate room to setup the recording setup. So whats the next best thing, FOH?

The last gig I just did I was at FOH and it was nice being able to talk to the house engineer, especially when trouble came (why does trouble always come ).

Since the topic is splitters, whats the approx. max distance for passive splitters? Do non-iso splitters always drop the signal a couple db?

Thanks,


Mark
Old 19th December 2003
  #18
Gear interested
 

Max Distance aka Mic Loading

There is no maximum distance, but performance does drop slowly as the cables get longer. There will be high frequency rolloff dictacted by the capacitance per foot of the cable, and the input impence of the mic pre (and to a lesser extent by the output impedence of the mic). The corner frequency of the rolloff will get lower as the cable length increases.

The transformers isolate DC grounding problems and provide common mode noise rejection, but as far as the real audio signals are concerned, everything appears wired together. In other words from the Microphone's point of view it is driving two or three mic pres and ALL the cable: The actual signal drop will depend on the output impence of the mic and the input impedence of everything it is driving.

All passive splits will drop the signal a little bit whether they are isolated with transformers or just hard wired. 3dB is probably a good guess, but the variation is probably quite substantial. For example, a condenser mic driving two direct coupled mics press (2.4K each) will probably be a less than 100 ohm source driving a 1.2K load. This would be almost no loss. A dynamic mic with a 400 ohm output impedence driving three transformer inputs at 1.2K each would be seeing a 6dB drop. Those are probably pretty close to worse case scenarios.
Old 10th April 2009
  #19
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Thread Starter
I felt Herbie's explanation above needed to be addressed again, especially for the folks that are still using isolation transformers. Food for thought and a great read.

Quote:
Originally Posted by hrob View Post
There is no maximum distance, but performance does drop slowly as the cables get longer. There will be high frequency rolloff dictacted by the capacitance per foot of the cable, and the input impence of the mic pre (and to a lesser extent by the output impedence of the mic). The corner frequency of the rolloff will get lower as the cable length increases.

The transformers isolate DC grounding problems and provide common mode noise rejection, but as far as the real audio signals are concerned, everything appears wired together. In other words from the Microphone's point of view it is driving two or three mic pres and ALL the cable: The actual signal drop will depend on the output impence of the mic and the input impedence of everything it is driving.

All passive splits will drop the signal a little bit whether they are isolated with transformers or just hard wired. 3dB is probably a good guess, but the variation is probably quite substantial. For example, a condenser mic driving two direct coupled mics press (2.4K each) will probably be a less than 100 ohm source driving a 1.2K load. This would be almost no loss. A dynamic mic with a 400 ohm output impedence driving three transformer inputs at 1.2K each would be seeing a 6dB drop. Those are probably pretty close to worse case scenarios.
Old 10th April 2009
  #20
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huub's Avatar
Nowadays we take passive splits without transformers!
With a madi stagebox with remote mic amps, we're isolated anyway (we take power from the same source the PA does) and without copper and transformers the sound is so cleaaaaaan
All modern microphones can easily be passively split to 3 mixer inputs (well, it all depends on impedance, buth with our Lawo box and usually Digico or Midas mixers, all goes perfectly well)

Huub
Old 10th April 2009
  #21
Gear Maniac
 

Hello,

Our newest system uses fiber to stage with remote controlled pres. One of the keys for us has been to separate the splitter system from the fiber system because every show is different and requires a different configuration. The splitters are two 56pr with Lundahl transformers which sound very nice indeed, in my opinion better than the standard Jensen. A very nice transformer that will do real line level is the Cinemag 3-way line level (don't have the model number), a pa company we frequently work with uses this because it's very high quality, has 3 splits plus direct, and we isolate everything - mics, line level returns, etc.
Years ago a high-visibility pa mixer started insisting every single thing between the tv truck and the sound system be transformer isolated. In addition everything between foh and monitors is now isolated. Mics, line level returns, communications, everything. Our broadcast systems have never been quieter as a result.

Hugh
Old 10th April 2009
  #22
Registered User
 

Hey, Hugh. What are you using for your preamps and fiber system? I'm looking at building this type of rig and haven't quite decided on what's best and most flexible. Any chance of you posting pictures in one of the show and tell threads? Otherwise I will appreciate words instead. Thank you.
Old 10th April 2009
  #23
Lives for gear
 

Wonderful thread - thank you Mr. Remote!

How many of you split line-level? Our pres are always on stage and in my limited understanding I expect that splitting the more robust line-level signal could sound better or have less pitfalls?

On the other hand, most off the shelf splitters appear designed to run at mic-level. Sometimes they have pads to knock it down which seems like a less than ideal solution and implies that they somehow don't have the headroom for it...

Any recommendations on splitters that can handle line-level really well?

What should I be looking for to know that it handles this?

Many Thanks,
Silas
Old 10th April 2009
  #24
Gear Maniac
 

Hello,

BT - We use Calrec's Hydra audio networking system. The Calrec desk recognizes the Hydra boxes as part of itself, so when you're adjusting the pre on the desk you're actually adjusting it out at the stage. Ridiculously high quality, those Calrec boxes.
I don't have any pictures of the Hydra system itself - that's a good idea. There are pictures of the audio room and control room of our newest truck in a previous thread.
https://www.gearslutz.com/board/remot...ote-truck.html

Silas - There are pros and cons to splitting line level.
Pros - things are somewhat impedance-independent, as most line level outputs are quite low impedance and most line level inputs are high impedance, so adding a split doesn't affect much. Splitting at mic level causes the mic's output impedance and the preamps' input impedance to affect levels and response.
Cons - If you're splitting those mics to house and monitors they won't like you controlling the mic pre gain, they want their own. That's the biggest reason we're still using passive mic level splits. Also, splitting line level requires a BIG, expensive transformer. Jensen, Lundahl, and Cinemag all make very nice mic-level splitting transformers but doing a good line level transformer takes a big, well-designed unit to sound right. Many transformers will advertise that they do line level, but when you start comparing specs they only do with low distortion above a certain frequency. Transformers have a tougher time at low frequencies. Low distortion, high level operation at low frequencies while still maintaining adequate bandwidth on the high end is no easy design task.
I recommend the Cinemag line level transformers. They spun off from Jensen and if you call them and discuss your needs they can recommend some solutions. Things you should look for are bandwidth, max level at low frequencies, CMRR at all frequencies, and level differences between windings. Whirlwind will fabricate a splitter using whatever transformer you decide you like, so I'd suggest you get several manufacturers' models and give a listen. That's what I did when I went with the Lundahls.

Hugh
Old 11th April 2009
  #25
Gear addict
 

Which would be more economical? A splitter box with XLR inputs, and two multipin outs, one transformer iso or just a plain passive split or a pathbay with multipin input and two multipin outputs, one transformer iso split of the input and the other normal outputs of the gear the inputs are routed to from the multipin?

So basically, either an external splitter box with multipin outputs and XLR input or a rack mount patchbay with multipin input, multipin split output and a multipin output or normal output patching bay.

Want to add a splitter to my remote rig that can easily intergrate into many different situations i.e. taking direct outs from a FOH or Monitor desk, taking a split from a multicore at either Monitor or FOH or conenct directly up to FOH split and then give someone else a split if doing FOH with the rig, which it is capable of.

The patch bay system I would have to design and get built or build it myself and the external splitter I could buy preamde, possibly from whirlwind, finding the modells is the hard problem. Need minimum 24 input to two splits, up to 32 inputs to two splits.

I want to also build a custom multicore. Box either end, FOH end gives a multipin for inputs and returns on a single box, the stage end gives a multipin for monitors and multipins for drop boxes for inputs and a drop box for outputs.
Old 12th April 2009
  #26
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jude's Avatar
 

when i get time to do live recordings i use 3 klark tecknics dn1248. sound superb to my ears
Old 13th April 2009
  #27
I designed and built my own, based on the designs from Jensen.

It is 2 way passive spilt; one direect, one isolated.

Normally, I provide mics and stage cabling. I go from the mics to my split; the direct goes to record, the iso goes to the house stage box (where it is often split between monitorland and FOH- i get away with this because the venues I record at know and trust me and the headliner hired me).

it is a 24 channel, jensen transformer isolated split in a two rack space custom wood box.

the only "bells and whistles" is a ground lift switch on each channel.
Old 20th April 2009
  #28
Gear interested
 
Danno's Avatar
 

With the plethora of radio mics, hidden cell phones, tech's 2-ways and poor shielding used on some house systems, I have in the last few years resorted to using the transformer side of the iso with a few custom ferrite beads and chokes added just to be on the safe side - to notch all of the extraneous RF floating around.

Those clam shell torriods have come in handy several times. I let FOH provide phantom on the direct and keep the custom built Jensen xformer split for myself normally. Can't tell you how many times I have had a cell silently ping the tower in somebody's pocket. stike

Danno
Old 21st April 2009
  #29
Lives for gear
 

Quote:
Originally Posted by hrob View Post
There will be high frequency rolloff dictacted by the capacitance per foot of the cable, and the input impence of the mic pre (and to a lesser extent by the output impedence of the mic). The corner frequency of the rolloff will get lower as the cable length increases.
Hi!

The output impedance of the source forms a first order lowpass with the paralell capacitance of the cable. The load of the receiving end is typically high enough leaving the source impedance and cable capacitance those that set the corner frequency.


/Peter
Old 21st April 2009
  #30
Lives for gear
 

Many thanks Hugh!

-Silas

Quote:
Originally Posted by HughH View Post
Hello,

BT - We use Calrec's Hydra audio networking system. The Calrec desk recognizes the Hydra boxes as part of itself, so when you're adjusting the pre on the desk you're actually adjusting it out at the stage. Ridiculously high quality, those Calrec boxes.
I don't have any pictures of the Hydra system itself - that's a good idea. There are pictures of the audio room and control room of our newest truck in a previous thread.
https://www.gearslutz.com/board/remot...ote-truck.html

Silas - There are pros and cons to splitting line level.
Pros - things are somewhat impedance-independent, as most line level outputs are quite low impedance and most line level inputs are high impedance, so adding a split doesn't affect much. Splitting at mic level causes the mic's output impedance and the preamps' input impedance to affect levels and response.
Cons - If you're splitting those mics to house and monitors they won't like you controlling the mic pre gain, they want their own. That's the biggest reason we're still using passive mic level splits. Also, splitting line level requires a BIG, expensive transformer. Jensen, Lundahl, and Cinemag all make very nice mic-level splitting transformers but doing a good line level transformer takes a big, well-designed unit to sound right. Many transformers will advertise that they do line level, but when you start comparing specs they only do with low distortion above a certain frequency. Transformers have a tougher time at low frequencies. Low distortion, high level operation at low frequencies while still maintaining adequate bandwidth on the high end is no easy design task.
I recommend the Cinemag line level transformers. They spun off from Jensen and if you call them and discuss your needs they can recommend some solutions. Things you should look for are bandwidth, max level at low frequencies, CMRR at all frequencies, and level differences between windings. Whirlwind will fabricate a splitter using whatever transformer you decide you like, so I'd suggest you get several manufacturers' models and give a listen. That's what I did when I went with the Lundahls.

Hugh
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