Any microphone experts out there?
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From: Midge on 18 Jul 2010 03:37 Have a small microphone mixer http://www.audiomate.co.uk/PDF/G105C.pdf I've been using a couple of dynamic microphones on it, but I wondered if it was possible to either get a tie-clip microphone (these seem to be electret condenser) which can be plugged straight in OR match the different technologies somehow. Thanks, Midge.
From: Ian Bell on 18 Jul 2010 08:36 Midge wrote: > Have a small microphone mixer http://www.audiomate.co.uk/PDF/G105C.pdf > > I've been using a couple of dynamic microphones on it, but I wondered if it > was possible to either get a tie-clip microphone (these seem to be electret > condenser) which can be plugged straight in OR match the different > technologies somehow. > > Thanks, Midge. > > If you use an electret mic with built in battery then you should be able to plug it straight in. Cheers ian
From: Jim Thompson on 18 Jul 2010 11:32 On Sun, 18 Jul 2010 08:37:46 +0100, "Midge" <midge(a)somewhere.com> wrote: >Have a small microphone mixer http://www.audiomate.co.uk/PDF/G105C.pdf > >I've been using a couple of dynamic microphones on it, but I wondered if it >was possible to either get a tie-clip microphone (these seem to be electret >condenser) which can be plugged straight in OR match the different >technologies somehow. > >Thanks, Midge. > If the electret has a built-in FET buffer, all you'll need is power for the FET. Otherwise the Audiomate input impedance is too low. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | "What would happen to [Obama's] vanity if he didn�t have us to throw alms to? What would become of his strength if he didn�t have weaker people to dominate? What would he do with himself if he didn�t keep us around as dependents? It�s quite alright, really, I�m not criticizing him, it�s just a law of human nature." -Ayn Rand, "Atlas Shrugged"
From: Phil Hobbs on 18 Jul 2010 13:36 Jim Thompson wrote: > On Sun, 18 Jul 2010 08:37:46 +0100, "Midge" <midge(a)somewhere.com> > wrote: > >> Have a small microphone mixer http://www.audiomate.co.uk/PDF/G105C.pdf >> >> I've been using a couple of dynamic microphones on it, but I wondered if it >> was possible to either get a tie-clip microphone (these seem to be electret >> condenser) which can be plugged straight in OR match the different >> technologies somehow. >> >> Thanks, Midge. >> > > If the electret has a built-in FET buffer, all you'll need is power > for the FET. > > Otherwise the Audiomate input impedance is too low. > > ...Jim Thompson As an aside, does the standard explanation of how electret mics work bother anyone but me? It's usually stated that the 'frozen in' electric polarization in the material works just the same as the applied voltage in a real capacitive mic. This is of course nonsense--charges such as air ions migrate around and eventually neutralize any E field external to the electret material, so that waving it around does nothing whatever. (Leakage--that's why you have to keep the capacitance mic's supply connected for it to work, duh.) The reality appears to be that they work by a combination of the piezoelectric effect (like a quartz crystal) and the variation of capacitance with stress (like coaxial cable with a DC voltage on it). Any comments from audio folks? Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Jim Thompson on 18 Jul 2010 14:18
On Sun, 18 Jul 2010 13:36:42 -0400, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >Jim Thompson wrote: >> On Sun, 18 Jul 2010 08:37:46 +0100, "Midge" <midge(a)somewhere.com> >> wrote: >> >>> Have a small microphone mixer http://www.audiomate.co.uk/PDF/G105C.pdf >>> >>> I've been using a couple of dynamic microphones on it, but I wondered if it >>> was possible to either get a tie-clip microphone (these seem to be electret >>> condenser) which can be plugged straight in OR match the different >>> technologies somehow. >>> >>> Thanks, Midge. >>> >> >> If the electret has a built-in FET buffer, all you'll need is power >> for the FET. >> >> Otherwise the Audiomate input impedance is too low. >> >> ...Jim Thompson > >As an aside, does the standard explanation of how electret mics work >bother anyone but me? It's usually stated that the 'frozen in' >electric polarization in the material works just the same as the applied >voltage in a real capacitive mic. This is of course nonsense--charges >such as air ions migrate around and eventually neutralize any E field >external to the electret material, so that waving it around does nothing >whatever. (Leakage--that's why you have to keep the capacitance mic's >supply connected for it to work, duh.) > >The reality appears to be that they work by a combination of the >piezoelectric effect (like a quartz crystal) and the variation of >capacitance with stress (like coaxial cable with a DC voltage on it). > >Any comments from audio folks? > >Cheers > >Phil Hobbs I've used them many times in hearing-aid chip designs, but I have no idea of how they actually work. The leader, in hearing-aid usage is Knowles... http://www.knowles.com/search/technologies/tech_condenser.jsp But I've also used a MIMS equivalent (Akustica) which was simply a capacitor biased with a _very_high_valued_ "resistor", powered from a 4X charge-pump (my part of the design). ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Friday is Wine and Cheeseburger Day |