Seeking help before upgrading my hardware

[chess]

Hi there,

I've been podcasting for about 6 months now and am finishing up my 25th episode. It's a podcast about Linux, so it's mostly talk (just me) with some listener audio comments, bumper tracks, and opening and closing music as well.

Anyway, I've been using a pretty cheap setup to record -- an altec lansing headset plugged into an iriver 790. I pull the audio off the iriver and do my post-production in Audacity on my Linux machine.

I'd like to upgrade my setup to improve my sound and to make it possible for future interviews, either over skype or some other means. I can record my skype conversations now, but I'd really like to be able to have a second mic or to be able to pipe in outside audio (i.e. the audio comments people send me) so I can basically record a "live" show and mix in audio. So, I think I need to get a mixer and maybe a better mic. After reading through the forums here at length, I am leaning towards the Behringer UB802 Eurorack Mixer and the MXL 990 Condenser Microphone with Shockmount. I am looking to spend about $100 and these two items are in that budget.

My questions are:

What are your thoughts on these two items? Anything else I should look at?

Do I also need to buy cables for the mic or do they come with the mic? If I need to buy cables, what kind? (I have no knowledge of audio cables here other than basic rca type cables). How much are they? Do I need a special cable from the mixer to my soundcard on the computer?

Can I use this mixer to mix in audio from a second computer? I am thinking of having a laptop connected to the mixer so I can play these audio comments etc. and be able to talk over the comments when recording. Hopefully, that makes sense. Any special cable for this?

Thanks for your input.

[pwfenton]

A lot of questions there. Basically... you are on the right track. The two items you mentioned are a great place to start. You should be able to do very well with that mixer and that microphone. Good mics don't usually come with cables. Depending on length and brand, you should be able to get a cable for that mic for around $10 to $20. Not only is it a great idea to use a second computer to playback things you want to mix into your program... it is the absolute best way to record Skype conversations. Using the mixer... you can record your own voice over that nice mic on one track... and record your guest via skype from the laptop on another track. Probably the easiest way to do it would be to also use that headset mic into the laptop so that the person on Skype can hear you.

The cables that you use to connect the computers to the mixer will depend on the mixer. The end that plugs into the computers will most likely be a stereo mini plug... and the other end will depend on what your new mixer requires for a "line in" and a "line out". You will probably have a single mini-plug on one end and then two mono plugs (right and left) on the other end.

[X Pat Radio]

I love your Linux Reality podcast Chess!

The mixer is a good place to start, but for the microphone... I disagree. I think you would be better off buying a dynamic mic rather than a condenser. Not having a sound proof room to record in, I found the condenser mics pick up too much stuff.

I would suggest you spend a little extra and look at a Sure SM57 w/windcreen (or SM58). These mics are very popular and can be found at any music store. I think I paid $89 for my SM57.

[chess]

Great help, thanks guys! I will keep researching these mics, but since I will be recording in a less-than-silent room :) I guess the dynamic mic is probably the better way to go.

Thanks!

[pwfenton]

Great help, thanks guys! I will keep researching these mics, but since I will be recording in a less-than-silent room :) I guess the dynamic mic is probably the better way to go.

Thanks!

Actually, this is completely false. Each microphone channel on that mixer has a "gain" control separate from the volume level. This is where you adjust the sensitivity of your microphone. Neither the dynamic nor the condenser is any better than the other in a noisy environment. Turning the gain down and speaking closer to the microphone will do the most towards minimizing background sound.

I see this particular bit of misinformation here all the time and it is very frustrating because it is just not correct. The OUTPUT of the condenser mic is much hotter so the gain must be set lower. Folks who make this claim either have made this assumption because they don't have a way to adjust the gain, or they have a way but just have never learned how to use it.

[roadrageradio]

Yes, indeed we have had this discussion before, and we can go on just repeating our positions as if that will somehow make us seem to be right.

Or, you can look at the physics.

A dynamic mic has a moving coil of wire inside its capsule. To get recorded sound, the coil has to move and that takes sound pressure.

A condenser mic uses a very thin plate of metal foil. Getting that to move requires much less sound pressure.

The difference is huge. For an EV RE-20 (dynamic) the sensitivity is 1.5 mV. For their new EV Blue (condenser) it's 10 mV, almost 7 times more sensitive.

So, set up two good mics, a dynamic and a condenser. Set the mixer trim and output level to any definition of optimum voice recording that you like. Then leave the room with the mics live and recording.

Come back in an hour. Which track will have a clearer sound of the dog barking, the ambulance that passed by on the road, the air conditioner cycling in another room, or of you closing the door when you left?

Condenser mics are more sensitive. That means you have to control the ambient better. You can do some of this by twisting knobs on the mixer, but I don't think you can do it all that way. It helps to be in a quieter room.

[WildeGeek]

A dynamic mic has a moving coil of wire inside its capsule. To get recorded sound, the coil has to move and that takes sound pressure.

A condenser mic uses a very thin plate of metal foil. Getting that to move requires much less sound pressure.

The difference is huge. For an EV RE-20 (dynamic) the sensitivity is 1.5 mV. For their new EV Blue (condenser) it's 10 mV, almost 7 times more sensitive.
The subjective difference in sensitivity to background noises does exist between condenser and dynamic microphones, but not because of their output voltage. If you put a dynamic microphone and a condenser microphone side-by-side, and adjusted your mixer inputs so that both mics yielded the same signal level at the output of your mixer for a given sound-pressure level, you might still hear the difference roadrageradio (http://www.podcastalley.com/forum/profile.php?mode=viewprofile&u=2069) describes.

I've got a translation of classic book in front of me, The Handbook of Entertainment Electronics (or Aschenbuch der Unterhaltungselektronik, if you prefer). This book was originally published by the West German Public Broadcasting Network, WDR (http://www.wdr.de/), copyright 1978. The chapter on microphones was written by Dr. Gerhart Bore. Dr. Bore was the chief scientist at Georg Neumann GMBH (http://www.neumann.com/) for most of those years they were inventing the technologies and designing the microphones that everyone is still trying to copy today.

I tried to excerpt small snippets of his discussion to be easily readable for the greatest portion of the PCA audience, but instead I'm going to resort to paraphrasing:

Just like a drum head, all microphone diaphragms are resonant and will most sympathetically vibrate at a particular frequency. This is dependent on a lot of things but mostly on the mass of that diaphragm.

Modern quality condenser mics have a diaphragm made of some light plastic, usually mylar, with gold vapor-deposited a couple of molecules thick on them. Their mass is so low that they're designed to resonate above the range of human hearing. Because of that, their sensitivity to lower frequencies decreases (more or less) linearly below that resonant frequency. Equalizer circuitry in the microphone compensates for this effect, making the output relatively flat down to very low frequencies. Because the mechanical energy extracted from the air is so little, condenser mics require an internal amplifer to drive the signal down the cable.

Typical dynamic microphones have diaphragm assemblies made of several components, including the diaphragm surface itself (usually foil or plastic), the spider or spring mounting the diaphragm to the magnet assembly, and the coil assembly (usually an epoxied-together cylindrical coil of wire that forms a tube). This whole assembly, compared to the condenser mic diaphragm, is quite heavy, so they're designed to resonate at the bottom or below the range of human hearing. Their sensitivity to higher frequencies decreases (more or less) linearly above that resonant frequency. Equalizer circuitry in the microphone compensates for this effect, making the output relatively flat up toward the highest audible frequencies. The movement of the coil, as driven by the diaphragm, generates all of the electrical energy output from the mic, and that requires a greater amount of mechanical energy to be extraced from the air.

These two designs have very different impulse response characteristics. Impulse response is the term for the way a microphone responds to a single, near-instantaneous change in air pressure (which sounds like a single click). Perfect impulses are often created in anechoic chambers by an electric spark. Anyway, a condenser microphone responds to an impulse rather accurately, with a little bit of supersonic ringing. A dynamic mic responds with some subsonic ringing, plus ringing at a number of harmonic frequencies above that subsonic frequency.

A more practical, and real-world test that would shed light on the subjective sensitivity difference between these two designs, is their tone burst length response. This test measures how long, and at what SPL ([b]Sound Pressure Level) you have to present a particular constant-SPL, fixed-frequency sound to a microphone before it's accurately responding in phase and in amplitude. The closer this tone is to the microphone's resonant frequency, the fewer cycles it takes to get the diaphragm moving in step with the sound source. So at relatively high frequencies, even at low SPLs, condenser microphones take very few (often less than 1) cycles. A dynamic mic can take 5-10 cycles near the high end of its range, and at higher SPLs, before it responds faithfully.

There are also small differences in the pressure linearity of the diaphragm structures, and diode effects in the cable connectors that are a little more pronounced if the mic output is lower. There are distortions in the amplifier circuit in condenser microphones, and distortions cause by non-linear electrical loading of the output of dynamic mics. But Dr. Bore says that those effects are insignificant compared to the effects described above.

Also, the integrity of the microphone's polar response is better the smaller the entire diaphragm and housing (though that's not the only factor). So whichever mic is physically smaller, will typically have flatter frequency response off-axis. That could mean reproducing unwanted background sounds more faithfully.

So you can have two microphones side-by-side, a condenser and a dynamic, each appropriately amplified to give you the same recording level for the same sound source. They will emphasize different noises in your background. The condenser picks up more of the higher, faster (or shorter-lived) sounds, and the dynamic pick up more rumble.

Condenser mics are more sensitive. That means you have to control the ambient better. You can do some of this by twisting knobs on the mixer, but I don't think you can do it all that way. It helps to be in a quieter room.
I would argue that you can't do it at all by adjusting knobs on the mixer -- except if you're compensating the total gain for talking louder or getting closer to the microphone.

Was this more than you wanted to know?

P.S. No disrespect meant to P-Dub. You are right in that it's not the electrical sensitivity that causes this effect. But the effect is real.

[roadrageradio]

Thank you for that post, WildeGeek. I know I learned quite a bit from what you wrote.

There is no better way to settle an argument than to have somebody who knows what he's talking about join the conversation.

[pwfenton]

Thank you for that post, WildeGeek. I know I learned quite a bit from what you wrote.

There is no better way to settle an argument than to have somebody who knows what he's talking about join the conversation.

The implication being of course that I don't know what I'm talking about, and that quoting a German textbook that examines, among many other things, recording the sound of a single spark in an anechoic chamber settles the argument. I have been making audio recordings for 47 years. I got started being paid to do that 40 years ago. In practical terms I'd say I know how to produce just about any kind of sound that I want to.

The argument is indeed settled however, because I have no interest in participating in an argument. My intent was to share my experience in regards to the issue of which would be the better microphone for "Chess" to buy. My experience is unchanged, and my recommendation is unchanged. As I said earlier, minimizing background sound can be controlled by lowering the gain and microphone placement, facts which were repeated in WildeGeek's post.

That said... I have all kinds of microphones... my wife would say I have too many microphones. I have used everything from $3000 Neumanns to $49 Peaveys. But currently the mic I use for my own voice is indeed a dynamic microphone. Not because it records less unwanted noise... but because I love the way it makes my voice sound. Audio is subjective, and it is judged by ears. If I could afford a $3000 Neumann I might use that instead. Not sure though... I'd have to A/B them :-)

[roadrageradio]

Thank you for that post, WildeGeek. I know I learned quite a bit from what you wrote.

There is no better way to settle an argument than to have somebody who knows what he's talking about join the conversation.

The implication being of course that I don't know what I'm talking about ...


It was your INFERENCE, pw, not my implication. IT'S NOT ALWAYS ABOUT YOU.

The line was self-deprecation and acknowledgement, since Wilde's comments were mostly corrections and clarifications of what I had written.

And he did it with class.

And, yes, that IS an implication about the way you did it last time.

[chess]

Well, I certainly did not mean for my post to start an argument! :)

I sincerely appreciate all the thoughts and feedback. All of you have more experience in audio recording than I, so it's helpful to hear all the perspectives. If anything, it shows me that, like pwfenton said, audio is subjective. Maybe the best thing is for me to get one or two microphones from somewhere that has a nice return policy and just try them out.

Thanks again for everyone's replies. Good food for thought.

[pwfenton]

Well, I certainly did not mean for my post to start an argument! :)

We're on the Internet... everything starts an argument. It's a Wikiworld.

I sincerely appreciate all the thoughts and feedback. All of you have more experience in audio recording than I, so it's helpful to hear all the perspectives. If anything, it shows me that, like pwfenton said, audio is subjective. Maybe the best thing is for me to get one or two microphones from somewhere that has a nice return policy and just try them out.

It depends where you live, I guess, but often you can find places that rent microphones. Not only do you get to try before you buy... but you can get a pretty good idea of how rugged they are. Rental mics need to stand up to abuse. You are less likely to find condenser mics for rent because they are more fragile than dynamics. They also don't like moisture.

Right now, I use a Heil PR-40, which is a dynamic mic. I cost me $270. But it put a mic that cost me twice that much into the closet because it just sounds so **** good... at least on my voice.

There are very real, and esoteric, technical reasons why it makes my voice record better. But the decision can be made with the ears.

That MXL 990 with a shock mount is a killer buy at $59.95 I haven't seen anything better for that money. It could even turn out to be the BEST mic for your voice. Like I said... it's subjective. Do people like your podcast because of the mic you use? I'd say that is a universal NO. The converse might be true though... that people don't listen to your content because you sound bad. But that represents a huge range.

[WildeGeek]

The implication being of course that I don't know what I'm talking about, and that quoting a German textbook that examines, among many other things, recording the sound of a single spark in an anechoic chamber settles the argument.
I wasn't implying that your comments were from DRE (http://improbable.com/2006/07/28/direct-translation/). But if anyone is an authority on the physics of microphones, I would expect that Dr. Bore would be respected as such. None-the-less, I agree with you that ultimately, it boils down to subjective, aesthetic decisions. But understanding the physics (at least a little) does take some of the mysticism out of it.

I have been making audio recordings for 47 years. I got started being paid to do that 40 years ago. In practical terms I'd say I know how to produce just about any kind of sound that I want to.
So you have me beat by about 10 years on that score. But I did have the interesting experience of being in charge of factory service for some pretty pricey microphones (http://bssc.sel.sony.com/BroadcastandBusiness/DisplayModel?id=24120) for 5 years of my career.

That said... I have all kinds of microphones... my wife would say I have too many microphones. I have used everything from $3000 Neumanns to $49 Peaveys. But currently the mic I use for my own voice is indeed a dynamic microphone. Not because it records less unwanted noise... but because I love the way it makes my voice sound. Audio is subjective, and it is judged by ears. If I could afford a $3000 Neumann I might use that instead. Not sure though... I'd have to A/B them :-)
I too have more microphones that I would ever likely be able to use at any one time. I settled on a Shure SM-7B (http://www.shure.com/ProAudio/Products/WiredMicrophones/us_pro_SM7B_content) for my main narration microphone (Shure's answer to the more popular Electrovoice RE-20 (http://www.electrovoice.com/products/91.html)). I experimented with some condensers early-on, including a Neumann TLM-170 (http://www.neumann.com/?lang=en&id=hist_microphones&cid=tlm170i_publications), Neumann KMS-84 (http://www.neumann.com/?lang=en&id=hist_microphones&cid=kms84_publications), and a Shure SM-81 (http://www.shure.com/ProAudio/Products/WiredMicrophones/us_pro_SM81-LC_content). All of those, for my taste, made my voice too breathy and edgy -- something I didn't want for a comparatively mellow show.

[X Pat Radio]

Right now, I use a Heil PR-40, which is a dynamic mic. I cost me $270. But it put a mic that cost me twice that much into the closet because it just sounds so d*mn good... at least on my voice.

I agree, the PR-40 is a steller microphone for the price. However I think chess is looking for a good low price microphone.

[WildeGeek]

I think chess is looking for a good low price microphone.
The reality is, that you can make some pretty cheap microphones sound pretty good if you're willing to take the time to understand their strengths and weaknesses, limitations and capabilities. And then you can make things even better by learning a bit about your other tools to understand work-arounds for the things you can't fix by good microphone usage.

For example, your audio in the MP3 file attached to http://www.linuxreality.com/podcast/episode-25-windows-networking-part-1/ sounds like you might be a bit too close to your particular microphone. I can hear the mouth and breath noises that a too-close microphone picks up.

However, your microphone output level and the preamp in your iRiver are apparently mis-matched, because you have a pretty high background hiss level. There are much higher-output mics you can connect to your iRiver that would reduce that problem. Some of them are really cheap (http://www.amazon.com/gp/product/B0007SVA0Y/104-3433603-1638325?v=glance&n=172282). (You can hear that mic in action toward the end of this show (http://www.wildebeat.net/index.cgi/2006/02/24#E031); listen to the ski instructor.)

I am leaning towards the Behringer UB802 Eurorack Mixer and the MXL 990 Condenser Microphone with Shockmount. I am looking to spend about $100 and these two items are in that budget.
...
What are your thoughts on these two items?
These seem to be popular models among other podcasters. But I'd listen to some shows I like and find out what they use.

My problem with that mixer is that the FX bus cannot be switched to pre-fader -- you can only send signals to that bus when the main channel fader is up. That could limit your flexibility in some interview situations (http://www.podcastalley.com/forum/viewtopic.php?t=12272), especially when using a phone interface or Skype.

I have no reason to believe that mic won't improve your sound, if used effectively, but don't be afraid to experiment with settings, placement, and the layout of your room.

Do I also need to buy cables for the mic or do they come with the mic?
It depends on the microphone. Check the specs on the manufacturer's web site NOT the dealer's).

If I need to buy cables, what kind? (I have no knowledge of audio cables here other than basic rca type cables). How much are they?
http://RSK.imageg.net/graphics/product_images/pRS1C-3095192w345.jpg THESE (http://www.radioshack.com/product/index.jsp?productId=2433031&cp=&origkw=xlr&kw=xlr&parentPage=search) would work.

Do I need a special cable from the mixer to my soundcard on the computer?
It depends on your sound card. My sound card (http://www.digigram.com/products/getinfo.htm?prod_key=8600) has XLR inputs and outputs, so I use an XLR male-to-female cable. Your sound card is probably different.

Can I use this mixer to mix in audio from a second computer?
Yes.

Any special cable for this?
Probably, though I/we would have to see the detailed specifications of those two products to be sure.

#####

Here's something to think about: People were making some awesome recordings in the 1930's using the best equipment of the day, which had poorer specifications that what you're talking about buying. The difference was, they went to a lot of effort to perfect the art of using what they had.