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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: voltronic on December 20, 2018, 06:39:41 AM

Title: 3V Plug-In-Power: Why bother?
Post by: voltronic on December 20, 2018, 06:39:41 AM
I know people have been asking this for years, but I want to reopen the issue:

Why do manufacturers build PIP mic inputs that only supply ~3V, when so many lav or other small electret mics need at least 5-9V polarization to perform properly?

This could be a power supply limitation for units like the Sony M10, but for recorders which already have multiple 48V phantom supplies it seems like designers could make this happen without too much difficulty, at the cost of battery runtime.

Is 3V PIP simply an outdated spec being perpetuated?  I am picturing those cheap plug-in mics that used to come with portable cassette recorders.  In a modern context, this voltage is so low that it is nearly useless.  I would like to see manufacturers either build these inputs to supply a higher voltage, or eliminate PIP altogether and just make it a line input.

What say you?
Title: Re: 3V Plug-In-Power: Why bother?
Post by: lsd2525 on December 20, 2018, 08:56:42 AM
I know people have been asking this for years, but I want to reopen the issue:

Why do manufacturers build PIP mic inputs that only supply ~3V, when so many lav or other small electret mics need at least 5-9V polarization to perform properly?

This could be a power supply limitation for units like the Sony M10, but for recorders which already have multiple 48V phantom supplies it seems like designers could make this happen without too much difficulty, at the cost of battery runtime.

Is 3V PIP simply an outdated spec being perpetuated?  I am picturing those cheap plug-in mics that used to come with portable cassette recorders.  In a modern context, this voltage is so low that it is nearly useless.  I would like to see manufacturers either build these inputs to supply a higher voltage, or eliminate PIP altogether and just make it a line input.

What say you?

I agree. If the M10 supplied 9v, it would be tremendous. Battery life is so good anyway that I would sacrifice a few hours not to have to tote a battery box.
Title: Re: 3V Plug-In-Power: Why bother?
Post by: chk on December 20, 2018, 09:43:16 AM
It would be great to have 9V out of the M10. My guess of why the “standard” is ~3V is because most PIP mics will “work” at low voltages and the typical use is low SPL situations such as recording voice, meetings, etc with these portable recorders. Perhaps the manufacturers assume that if you are recording high SPL sources, you’re going to be using a battery module of some sort (often wireless setups for lav mics) that puts out 9-12V. Purely a guess.
Title: Re: 3V Plug-In-Power: Why bother?
Post by: DavidPuddy on December 20, 2018, 09:56:38 AM
It would be great to have 9V out of the M10. My guess of why the “standard” is ~3V is because most PIP mics will “work” at low voltages and the typical use is low SPL situations such as recording voice, meetings, etc with these portable recorders. Perhaps the manufacturers assume that if you are recording high SPL sources, you’re going to be using a battery module of some sort (often wireless setups for lav mics) that puts out 9-12V. Purely a guess.

I agree. Most of the devices we use are meant for use as recorders with boundary microphones attached where a plug and play application is necessary, i.e. courtroom, board room, etc. An external microphone is an afterthought with this crowd as long as its intelligible enough. The 3v power supplied goes along the same lines - enough to get the job done with a non-professional lavalier mic.
Title: Re: 3V Plug-In-Power: Why bother?
Post by: voltronic on December 20, 2018, 12:28:14 PM
It would be great to have 9V out of the M10. My guess of why the “standard” is ~3V is because most PIP mics will “work” at low voltages and the typical use is low SPL situations such as recording voice, meetings, etc with these portable recorders. Perhaps the manufacturers assume that if you are recording high SPL sources, you’re going to be using a battery module of some sort (often wireless setups for lav mics) that puts out 9-12V. Purely a guess.

I agree. Most of the devices we use are meant for use as recorders with boundary microphones attached where a plug and play application is necessary, i.e. courtroom, board room, etc. An external microphone is an afterthought with this crowd as long as its intelligible enough. The 3v power supplied goes along the same lines - enough to get the job done with a non-professional lavalier mic.

Regarding the bold selection above:

Who is using non-professional lav mics?  I wouldn't even know where to find such a thing anymore.  All the lav mics I ever see are definitely "pro" quality.

How many lav mics are even out there anymore that use a 3.5mm TRS connector?  Sennheiser is the only one that comes to mind, and they are using all 3 conductors for one channel.

Why continue to use a consumer-level interface and powering scheme on devices that are billed as professional units?  Having a 3.5 mm stereo input is a great convenience, as a line level input to connect with consumer-grade gear.  To bill it as a "mic input" is somewhat misleading in today's context, where you'd be hard pressed to find any mics that perform properly with only 3V and also use this interface.

The only context I can think of where it still makes sense to have a 3.5 mm "mic" input on recorders such as the SD MixPre series are those little dedicated on-camera mics.  I just went through all of Rode's offerings since they make a bunch, and one of them does in fact use 3V PIP.  All of the others require an onboard 9V battery supply.
Title: Re: 3V Plug-In-Power: Why bother?
Post by: aaronji on December 20, 2018, 05:07:39 PM
Most small mics don't need polarization voltage as they are electrets and I can think of several of those that run on 3V.  Off the top of my head, there are the DPA 4063, the Countryman B3 (and some of their other lavs as well, I think) and the Roland CS10-EM.  There must be others.  Even if the mics you want to use need more bias, you can easily add a small battery box to the set-up and it's nice to have a mic level input if you're recording something relatively quiet (or with low sensitivity mics).   
Title: Re: 3V Plug-In-Power: Why bother?
Post by: chk on December 20, 2018, 05:19:53 PM
All of the church audio mics will run off 3V. AKG ck77s. They won’t be to full spec SPL handling-wise, but they work, often times quite well with reasonably loud sources (around 100db or so). I’m sure the list goes on...
Title: Re: 3V Plug-In-Power: Why bother?
Post by: weroflu on December 21, 2018, 03:22:30 AM
http://www.oscarsoundtech.com/services.html
Title: Re: 3V Plug-In-Power: Why bother?
Post by: voltronic on December 21, 2018, 08:32:32 AM
http://www.oscarsoundtech.com/services.html

Never seen those before.  They look very much another lav mic whose name I can't recall right now. 

Only 1.3V?  Wow!
Title: Re: 3V Plug-In-Power: Why bother?
Post by: Gil on December 21, 2018, 09:46:01 AM
I've never had any problems, and have had some great success, running AT943s off the DR-2d's PIP.
Title: Re: 3V Plug-In-Power: Why bother?
Post by: voltronic on December 21, 2018, 10:53:29 AM
I've never had any problems, and have had some great success, running AT943s off the DR-2d's PIP.

Really?  That's surprising!

I guess I may have been barking up the wrong tree here, guys.  Thanks for setting me straight!
Title: Re: 3V Plug-In-Power: Why bother?
Post by: Gil on December 21, 2018, 11:47:04 AM
I've never had any problems, and have had some great success, running AT943s off the DR-2d's PIP.

Really?  That's surprising!

I guess I may have been barking up the wrong tree here, guys.  Thanks for setting me straight!

Hey, I was surprised too. Honestly, I have no idea what the DR-2d puts out for PIP, but it's worked for me in both stealth and open scenarios. YMMV.