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Why do you want to go split that perfectly good mic anyway? Dynamics Plugins
Old 21st April 2009
  #31
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I guess I'm old school. I have a 24 ch. passive Whirlwind splitter with direct and transformer iso. outputs. There's usually a discussion with FOH ahead of time about who gets which set of outs. I'm usually ok with taking the iso outputs, and the ground lifts on every ch. have come in very handy in eleminating buzzes from lighting rigs etc. If its a jazz or acoustic music gig, I'll try to use the directs if it doesn't ruffle any feathers, and nothing is buzzing. I've also got a cheap little 8ch ART rackmounted splitter as a safety, in the case of a bad channel, but I haven't needed it yet.
If I ever have the budget, I'd love to put together a MADI based system with remote control pres near the stage like some of you guys have. That seems like a very cool way to work.
Cheers,
-GD
Old 28th December 2009
  #32
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Quote:
Originally Posted by hrob View Post
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.
Just to make sure I get it right (trying to get the hang of the impedance/splitter part): if I want to use a preamp with variable input impedance, I can actually still affect the performance of the mic with the variable input impedance while connected to the isolated ouput of a passive transformer? (direct connection of splitter to FOH)
Old 28th December 2009
  #33
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Quote:
Originally Posted by JazzP View Post
Just to make sure I get it right (trying to get the hang of the impedance/splitter part): if I want to use a preamp with variable input impedance, I can actually still affect the performance of the mic with the variable input impedance while connected to the isolated ouput of a passive transformer? (direct connection of splitter to FOH)
Yes, a 1:1 transformer splitter has no effect on the load impedance. It isn't usually a problem though.
Old 29th December 2009
  #34
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Ok, thanks for making that clear. But I assume you need to increase the variable input impedance of the preamp far more when using a splitter than when only a single preamp is connected to the mic. Still have to be carefull during a live recording though I think, best not to get the FOH engineers too much upset by increasing the impedance
Old 29th December 2009
  #35
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My friend thijs peters from dBMg here in holland has made 96 channels of active splitter with an Hi-Z switch per channel. You can use it to take a passive split from the PA and not load the mic more.. Or however one calls this technically correct.. You can rent em from him
Old 30th December 2009
  #36
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Hello,
One of the things to remember with passive splitters is that although you're galvanically isolated, the mic (to a first approximation) sees all the preamps in parallel. If you short one input, it will drastically (not completely) drop the signal on the others. If you use a variable input pre and change it, the other desks will see a small or large change, depending on the mic output impedance and the other desks' input impedance.

Hugh
Old 30th December 2009
  #37
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Quote:
Originally Posted by huub View Post
My friend thijs peters from dBMg here in holland has made 96 channels of active splitter with an Hi-Z switch per channel. You can use it to take a passive split from the PA and not load the mic more.. Or however one calls this technically correct.. You can rent em from him
Someone else told me they did this too. Used a 100k load. He didn't feel the result was worth it.
Old 30th December 2009
  #38
LX3
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Might be worth mentioning at this juncture that most live desks have mic inputs with an input impedance of 5k or more. (i.e. not the 1.3k "classic" mic input impedance).

So the total load of a three-way passive split - if you have mic pres with a 5k option anyhow - is actually around 1.6k, which is right on the money.

It does quietly infuriate me when I show up with a Lundahl or Jensen transformer splitter, then get a lecture off a band's FOH or monitor engineer about loading effects. The actual "problem", if there is one, is the effect of all that cable capacitance... but even on big analog festival setups, the rolloff should theoretically start somewhere over 20kHz... as long as you're not attaching 200m of multicore to your feed.

Actives have their advantages, but in practice I've had far more issues with rented active splitters than I've ever had with my passives.
Old 30th December 2009
  #39
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Very interesting.

Paul, what kind of problems have you had with active splitter systems?
Old 30th December 2009
  #40
LX3
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Hi Steve... Basically, channels not working at all, or not working properly. Pads not engaging, phantom going out, etc. I got caught out a few years ago, so I've learned to make it a priority to grab a phantom-powered mic and independently check every channel on any rented active splits that I'm faced with. That said, I always check every channel on my own splits as well once we're set up... but they always work.

Admittedly, it's been one particular manufacturer's active split system that has been a problem. And for all I know, it's one particular set of units from one rental company that are causing all the trouble here in the UK.

(No issues yet with KT splits. I have yet to do a gig where I've come across the XTAs. 98% of the time I'm using my own passive units which have been totally solid for the last seven years).

I've also heard of active splitters (yes, from that same well-known manufacturer) that worked fine in soundcheck, only to have channels randomly let go during the gig

I realise that some rental units do get pretty ragged, but you'd hope that the rental companies would maintain them properly. Some clearly don't. But that's a whole other subject.
Old 30th December 2009
  #41
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I do agree with the BSS splitters being unreliable at times.. Same with the XTA ones... probably because theyre old, and rental companies don't maintain em properly?
Old 30th December 2009
  #42
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Quote:
Originally Posted by LX3 View Post
Hi Steve... Basically, channels not working at all, or not working properly. Pads not engaging, phantom going out, etc. I got caught out a few years ago, so I've learned to make it a priority to grab a phantom-powered mic and independently check every channel on any rented active splits that I'm faced with. That said, I always check every channel on my own splits as well once we're set up... but they always work.

Admittedly, it's been one particular manufacturer's active split system that has been a problem. And for all I know, it's one particular set of units from one rental company that are causing all the trouble here in the UK.

(No issues yet with KT splits. I have yet to do a gig where I've come across the XTAs. 98% of the time I'm using my own passive units which have been totally solid for the last seven years).

I've also heard of active splitters (yes, from that same well-known manufacturer) that worked fine in soundcheck, only to have channels randomly let go during the gig

I realise that some rental units do get pretty ragged, but you'd hope that the rental companies would maintain them properly. Some clearly don't. But that's a whole other subject.
Yup, I totally understand where you're coming from.

Electronic devices can fail more times than passive iron and wire.
This is why we check each and every active splitter channel that goes out on a gig before it leaves the shop...

I mean, it's the front end for everyone's system; FOH, MON, REC and/or B'CAST!
Why would you want to find out on site that your mission critical equipment has a problem?

For that matter, we (nine out of ten times) check our entire system during the show prep at the field shop.
I just don't want to be dealing with issues on location that I could have addressed in my own home base.

I still have a forty channel BSS active splitter from the 80s that still working perfectly...
Well, almost perfectly; one LED on a channel is not working properly and a button on another channel switch is missing, so we have to use a small tool to turn it on/off.

That being said, all the important stuff is still working as usual and that's a good thing when it comes to old electronics.

Man, I don't remember when an active splitter channel failed us during the show.
That's got to be a serious drag; they usually go (fail) when you turn on the power or that's what I want to remember. heh

I rarely use rental companies; it's hard to trust them when they have failed you before.
Promises promises -- You (the rental industry) are only as good as your last gig.

IMO. the folks that keep things working before they leave their shops will last the longest.
Hey, this goes for all of us.


Quote:
Originally Posted by huub View Post
I do agree with the BSS splitters being unreliable at times.. Same with the XTA ones... probably because they're old, and rental companies don't maintain em properly?
It's true, Huub; it's all about the maintenance.
Not too many companies bother to check each and every channel.
They seem to only respond to a problem when someone complains and sometimes that never happens...

There's a certain NYC based rental company that promised us that the problem we found was fixed, but it never happened. Not only that, the written note of that exact problem was still on the device when rented again the following year.

Crazy stuff for sure.
Old 30th December 2009
  #43
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This is a cool tool to have:
The Ultimate XLR Cable Tester - Rat Sound Sniffer/Sender Pack

You can use the receiver only to test for phantom power without the sender.
Old 31st December 2009
  #44
LX3
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Those testers are quite cool, but in a system that incorporates a passive transformer split, they tend to see the transformer windings as a short across pins 2 & 3. We did a gig recently where there was a problem line or two, and the FOH engineer pulled out a tester, then proceeded to scream at me that our cabling and/or splitter was broken... Only after ten minutes of tracing faults did I suddenly realise why he was blaming us. Turned out it was the house wiring.

On-site, I find nothing beats some cans, an assistant and an SM58 (or better still, time permitting, a phantom-powered mic)
Old 31st December 2009
  #45
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Yes, a SM58 is cool, but a phantom powered mic is even cooler.
Old 31st December 2009
  #46
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Does anyone remember the old school way of recording live shows? Using independent mics for the recording would have to be the ultimate purist approach. At least think about it.
Old 31st December 2009
  #47
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What about using the Aphex digital snake, maybe with their distro hub? Maybe you wouldn't even need the hub? Would this be a viable solution to line splitting? It seems like an affordable solution to me. And the quality...
Attached Thumbnails
Why do you want to go split that perfectly good mic anyway?-anaconda_block-824_page.gif  
Old 31st December 2009
  #48
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How do these mic splitters maintain a proper voltage level for each split channel? and why is it that we never use these in studio situations to record one signal to many channels of different preamps for accurate A/B tests? or just for a variety of options to choose from come mix time?
Old 31st December 2009
  #49
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Quote:
Originally Posted by hazelmossobrien View Post
How do these mic splitters maintain a proper voltage level for each split channel? and why is it that we never use these in studio situations to record one signal to many channels of different preamps for accurate A/B tests? or just for a variety of options to choose from come mix time?
Anything that involves multiple A to D and D to A conversions would be frowned on in a studio environment usually.

Reason why splitters aren't commonly used in studios is that no split system is perfect. Perfect scenario is each mic hard patched into one preamp patched into a single channel of a recorder. That's purist. Improve it by decreasing the cable length of the analog signal path, increasing the quality of the signal path, and improving the performance by improving the environment etc.

Splitter systems are used to work around problems, but in an idealist studio environment are usually not necessary.
Old 31st December 2009
  #50
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Quote:
Originally Posted by mllrtms View Post
What about using the Aphex digital snake, maybe with their distro hub? Maybe you wouldn't even need the hub? Would this be a viable solution to line splitting? It seems like an affordable solution to me. And the quality...
Sure, but then you're sharing preamps. And that does not make life simpler.
Old 31st December 2009
  #51
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Quote:
Originally Posted by audioboffin View Post
Anything that involves multiple A to D and D to A conversions would be frowned on in a studio environment usually.
???

this is an analog situation.
Old 31st December 2009
  #52
LX3
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Quote:
Originally Posted by audioboffin View Post
Does anyone remember the old school way of recording live shows? Using independent mics for the recording would have to be the ultimate purist approach. At least think about it.
I don't think it's practical these days (typically 30-40 channels running at a typical gig), or acceptable from a visual point of view - most gigs we do are being filmed.

Although if there's time, we do put up "recording only" mics when we're not keen on the choices made for PA use, or when we need more coverage.

I find expensive passive transformer splits fairly "purist" anyway, as long as the total cable runs aren't excessive.
Old 31st December 2009
  #53
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Quote:
Originally Posted by hazelmossobrien View Post
???

this is an analog situation.
I was referring to the Aphex Anaconda system.
Old 1st January 2010
  #54
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Quote:
Originally Posted by audioboffin View Post
I was referring to the Aphex Anaconda system.

I would think in using the Anaconda in this context the only D/A conversion would be from snake to FOH. The D/A would not need to take place for the recording end as long as you have got a fiber in to your equipment. Simply take the source to pre to A/D through the cable run and into your DAW... No I guess I don't see where the multiple A/D - D/A conversion would take place but I can see why some folks would not like sharing mic pres. I think in many situations though it would be acceptable.

It could be that I'm overlooking some intrinsic detail here. I'm new to the remote end of the industry and am still trying to wrap my head around some of it. I appreciate the throwing around of ideas and knowledge on this site so please don't be afraid to blow holes in my line of thinking but it seems to me that other than the mic pre issue the Anaconda would be a great solution.
Old 1st January 2010
  #55
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The thing is, everybody has their way of doing things.
Having a transformer split is a no brainer.
Everyone can wrap around that concept because it's the most standard way to get your mics and DIs into each and every one's system each and every night.

I've seen folks use that system, but they still have a XFMR isolated splitter upstream feeding each system.

When you introduce equipment that may not be applicable to the various live sound companies out there you may be confronted with some resistance to using a system like that. Having a discussion about it during the show advance is a very good idea.

Now, don't get me wrong; Aphex makes some awesome gear and their Anaconda snake system is getting plenty of traction.

...I'm just saying.
Old 1st January 2010
  #56
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Quote:
Originally Posted by mllrtms
but I can see why some folks would not like sharing mic pres. I think in many situations though it would be acceptable.
There are only two circumstances where I would want to be sharing mic pres with FOH: 1. I am FOH. 2. We're recording a tour, carrying consoles, and gain structure has been preset during rehearsals.
Old 8th January 2010
  #57
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Quote:
Originally Posted by Remoteness View Post
All professional remote recording companies have both microphone and AC power isolation transformers.
Uninformed question here: Is an "AC power isolation transformer" part of a power conditioner or is it an additional piece of equipment? I can't seem to find anything referred to in this way. Thanks.
Old 8th January 2010
  #58
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Uninformed answer here: An AC power isolation transformer is usually an additional device that is the first thing to tie into. The ISO XFMR then can connect to a distro box then the UPS and/or power conditioners and such depending on how you designed the power in your rig.

With that said, they also have all in one units; I usually see this type of apparatus used in smaller systems.

Quote:
Originally Posted by studiotogo View Post
Uninformed question here: Is an "AC power isolation transformer" part of a power conditioner or is it an additional piece of equipment? I can't seem to find anything referred to in this way. Thanks.
Old 8th January 2010
  #59
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Quote:
Originally Posted by studiotogo View Post
Uninformed question here: Is an "AC power isolation transformer" part of a power conditioner or is it an additional piece of equipment? I can't seem to find anything referred to in this way. Thanks.
You can buy mains iso transformers either stand alone or as part of a fully featured power conditioner.

Have a look here for some general info AC Power Line Filter-isolators, Isolation transformers, Cable modem isolators, Power Conditioners
Old 11th January 2010
  #60
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Thanks for the answers even though I somewhat hijacked this thread...
So as I'm understanding things, the iso transformer included in a moderate to serious power conditioner is sufficient for a smaller setup.

For example, my power conditioner is a Monster Power PRO2500 and I use it to run a laptop and interface, a digital mixer, a usb hard drive, and a DAW.

But once you start playing with serious toys (i.e. a truck, etc.) the transformer needs to have a (substantially) higher capacity.
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