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* (This is my first time trying to record using a condenser mic and I have spent days trying to figure this problem out)

I am trying to connect an mxl 770 condenser microphone to my windows laptop to record audio. I purchased the following items:

MXL 770 Condenser Mic

InnoGear 48V Phantom Power Supply (with XLR cable)

XLR to 3.5mm Cord

My laptop has both a headphone jack and a microphone jack. I plug the "XLR to 3.5mm Cord" into the microphone jack of my laptop. When I record, I hear a horrible static sound behind my voice whenever I speak. The audio is of very bad quality and it sounds like my voice occasionally drops out/is distorted. Can anyone shed any possible light on to why I am experiencing this poor quality? Did I purchase the wrong items?

(Also, I should mention that if I turn the gain on my computer down to 0db, then the horrible static sound only occurs whenever I speak into the mic)

Thanks for any help.


Boswell Mon, 05/29/2017 - 00:58

The soundcard microphone input on a standard PC will not accept the output of a professional type of microphone.

You will need to get an audio interface that connects to a USB input. You could try part-exchanging the phantom power unit, as most audio interfaces provide phantom power. Have a look at something like the Focusrite Scarlett 2i2.

bouldersound Mon, 05/29/2017 - 10:25

You could fight with your current setup until you get it sort of working, but it would be less than ideal. It may be that you could use a different XLR-1/8" cable, one that terminates in an unbalanced "tip-sleeve" plug rather than a balanced "tip-ring-sleeve" plug as pictured. If the mic jack on the laptop does have TRS then it uses the three conductors for different purposes than a pro mic. Even if you can get the two working together you still have the issue of input monitoring. A USB interface solves that problem along with all the other things it does to make recording possible.

amcclure Mon, 05/29/2017 - 11:43

Thanks guys for the info. I had watched videos on YouTube of people using this method and their mic didn't sound even half as bad as mine is now. (Maybe I have an especially crappy soundcard?)

1) Boswell you recommended the Focusrite Scarlett. Since I only am using one mic, would this model work?

2) Just out of curiosity, why would anyone buy phantom power packs like the one I bought in the original post when you need an audio interface to record anything? It seems most audio interfaces have phantom power supplies as well.

bouldersound Mon, 05/29/2017 - 12:14

amcclure, post: 450601, member: 50609 wrote: Thanks guys for the info. I had watched videos on YouTube of people using this method and their mic didn't sound even half as bad as mine is now. (Maybe I have an especially crappy soundcard?)

It may be that they were using an XLR-TS (rather than TRS) cable. If your soundcard has a TRS mic jack it may be for stereo use: tip=left, ring=right, sleeve=ground. A pro mic uses the three conductors for balanced hot/cold/ground connection, which is not compatible with a stereo connector. It may be possible to adapt the output of the phantom power box to your laptop, but it will not be ideal. A USB interface makes the proper connection between mic and computer, and has other benefits.

amcclure, post: 450601, member: 50609 wrote: 2) Just out of curiosity, why would anyone buy phantom power packs like the one I bought in the original post when you need an audio interface to record anything? It seems most audio interfaces have phantom power supplies as well.

There is gear with mic inputs that lack phantom power, or sometimes you need to move the phantom power supply closer to the mic. I could see using them in a mobile recording rig where there is transformer isolation on a mic split (say, between the live mixing gear and a recording truck). If, say, there are audience mics going to the remote truck and they can't bypass the transformer isolated splitter, then they may need local phantom power.

pcrecord Mon, 05/29/2017 - 12:16

Yes the Scarlett Solo can do the job.

amcclure, post: 450601, member: 50609 wrote: Just out of curiosity, why would anyone buy phantom power packs like the one I bought in the original post when you need an audio interface to record anything? It seems most audio interfaces have phantom power supplies as well.

I've been asking myself the same question... I guess it would be of use if you were to record on old tape or other recorder that doen't have phantom power.

paulears Mon, 05/29/2017 - 12:46

Most phantom boxes have capacitors between the input and output to prevent the DC going to the mic going back the other way, but I suspect the real issue os that you are having to unbalance the balanced output of the phantom power supply to feed the input with your XLR to 3.5mm cable, which as purchased is not wired correctly. Shorting together pins 1 and 2 (or 1 and 3) in many of these boxes prevents the phantom circuit working properly, lowering the voltage the mic sees, and at the same time putting DC back up the spout - as Corporal Jones said, they don't like it up 'em.

Using the 3.5mm socket on a computer is so rarely successful on any of the quality stakes that a proper serious interface that lets you recording high quality and play back in high quality is essential. You have a nice mic, plugging it into a typical PC is a bit like putting paraffin in your sport's cars petrol tank.

amcclure Mon, 05/29/2017 - 13:25

That makes sense. Thanks everyone. Two last questions,

1) I want to be able to use headphones that have 3.5mm jacks but the audio interface has a ¼ inch TRS output jack. I assume I will need an adapter like the one below. I specifically would like to use "Beats By Dre" apple headphones but would really like to be able to swap in any pair of 3.5mm headphones. Would this type of adapter be suitable? Still not super sure I understand the different types of jacks...will do some reading up one it.

2) I notice that the Focusrite interface I listed above (as well as a few others I looked at) mention they offer phantom power. However, none of these devices appear to have a powerpack that plugs into an outlet. How are they providing phantom power? It can't be provided simply over usb from a laptop computer, can it?

paulears Mon, 05/29/2017 - 13:40

That adaptor is fine.

Some of the interfaces have mains power, but others take their power from the USB connection. This is 5V of course and they use a circuit to generate the 48V that phantom power mics need - actually, many can't at the current many mics need, and this occasionally causes problems, and others manage about 22V, which is enough to power some mics, but not all. The spec sets a current level, but many mic manufacturers vary considerably from it - 2mA is pretty average, but some designs need 3 or 4 times this current, and USB interfaces might struggle. Small condensers with pre-polarised diaphragms usually take less than 2mA, but the bigger types often use the 48V to polarise the diaphragm AND power their preamp circuit.

When you read up on jacks make sure you understand the basic types - which are pretty well 2 circuit (tip and sleeve) and 3 circuit (tip, ring and sleeve).

Many people assume that 2 circuits means mono and 3 stereo - this is correct when talking about headphone connections - but this is where people get confused with assuming 3 ALWAYS means stereo. It can be mono, balanced, it can be mono - but mic AND speaker, or even mono, just using TWO of the three circuits. Sennheiser on their radio mic packs use different combinations to set mic or line level - depending on the wiring. If you teach yourself to solder, you can make ANYTHING you need. Buying ready made ones is always tricky if you need different wiring.

Boswell Mon, 05/29/2017 - 15:25

The microphone inputs on computer motherboards have several problems when it comes to connecting a balanced mono microphone with an XLR connector:

(a) the computer inputs are usually stereo, i.e. two mono, unbalanced inputs connected to the ring and tip of a 3.5mm jack
(b) the microphone input jack supplies plug-in-power of about 5V for powering the output buffers of simple electret microphones
(c) even if you were to get your typical condenser microphone cabled correctly to the computer microphone input, the microphone's output level would easily overload the computer's input

My advice is not to try connecting a professional-style microphone to a computer microphone input jack, despite using what may look like suitable cables or adaptors.

DonnyThompson Tue, 05/30/2017 - 04:47

Beyond what my esteemed colleagues have already mentioned here, I would suggest that you consider a different pair of headphones.
If you are determined to mix with headphones (most prefer actual studio monitors) then
"Beats" headphones probably won't paint you an accurate picture of your audio - they have a pronounced hype (false response) in the low end, as well as a serious scooping out in the mid range, so they are what we would refer to as having a "colored" or "hyped" frequency range, and while they may be fine for listening, they won't give you an accurate sonic picture of what you are actually mixing.
For mixing purposes, you'll want a pair of HPs that are "flat" across the frequency spectrum, this will help you hear things far more accurately, and your mixes will translate more honestly to outside playback systems other than just your own.
For example, if you are using a pair of cans with an extended (hyped) bass range, your mixes will probably be bass "shy" when played back on an accurate audio system, because when using the Beats, your ears are being lied to into thinking that you already have plenty of bass response - when you really don't.
If the mid range is scooped out on the headphones, then your inclination will be to add mid range when you really don't have to, and when played back on more accurate systems, the mid range will be heavy, resulting in "harsh" or "honky" sounding mixes.
Look at headphones that have a relatively flat response. Audio Technica, Sennheiser, AKG, Sony, all make headphones that are relatively flat (certainly flatter than the Beats are) and for not all that much more money than the Beats.
Your mixes will be more honest, more accurate, and will translate much better to different playback systems.


DonnyThompson Tue, 05/30/2017 - 05:00

Oh, one more thing...
If you end up getting something like the Focusrite preamp/interface, make sure that it is set as the default audio device for your system.
Go to Windows control panel/sound, and disable the current built in soundcard. You shouldn't have to uninstall it, but you will want to make sure that it - as well as any other audio device drivers you may have - are all disabled, so that the Focusrite becomes your system's default audio device.
Otherwise, you may run into issues with your DAW software not knowing which device to use.
Trust the guys here on RO who have suggested that you go with a dedicated USB audio device.
Your phantom power will be handled, you'll have actual control over your mic's input gain, and it will work for you every time.
In all my years of doing computerized audio production and home studio consultation, I've never (not even once) seen a built in soundcard (sound blaster, Realtek, Conexant, etc) perform well enough to do good audio work. Those cards are principally designed for gaming and streaming audio playback - and aren't up to the task of recording hi quality audio.
Remember this: the quality of your audio will only ever be as good as the weakest link in the chain is. ;)

amcclure Tue, 05/30/2017 - 20:36

I went ahead and purchased the Scarlett Solo as you guys suggested. Also, in response to Donny, I was aware that Beats headphones boost the lows and do plan to swap out for a better pair soon. I will be sure to take a look at the brands you mentioned (and thanks for the "disabling the soundcard" tip!). Thanks again everyone