mic questions from newby

[RockyJ]

I will be recording orchestra and unamped vocal recitals. Sometimes from 5 rows back sometimes from back row.

Are the cardioids that noticeably 'tinny' as I have read or are they just not picking up the higher energy base from the sides of the theatre walls and such. Do they actually distort the sound?

I'm wanting to talk myself into cardioids to minimize theatre sounds. In an amped environment the audience and bounce effect are overpowered but not so in acoustic settings, but I don't want to lose bass.

and second question.

Why would I need bass roll off in omnidirectional's. Can't I just edit the sound file in my Goldwave editor.

[A440]

Look at the frequency response of cheaper cardioids. Most just go down to 100 Hz, an octave and a half below middle C. Perfect, perhaps, for a string quartet, but not an orchestra or a piano. Even a pair I had that claimed 40 Hz were notably anemic in the bass.

Then again, if you can spend a couple of hundred dollars, you can probably get a good full-frequency pair. Places like www.core-sound.com and www.soundprofessionals.com will let you try their mics for 30 days, so you could experiment for the price of shipping.

The sound might be a little sterile with cardioids, though. A hall with good acoustics makes the sound richer from the bounce and dispersion. (Bad acoustics will be an echo chamber, of course.) From the back row the cardioids will still pick up every audience sound in front of you--no way around it.

"Tinny" doesn't mean distorted--more like unnatural, without depth in the sound. There's a System of a Down recording in my album in the Live Recordings gallery with my (former) cardioids--you can hear what I mean. Very crisp, but no bottom. Believe me, there was bottom at the show.

The only reason anyone needs bass roll-off is because the preamp in the MD unit can't handle a lot of bass. Rock clubs tend to be bass-heavy, so some people just eliminate the problem that way--but to me that's lessening the fidelity of the original recording. It's better, as you say, to use a sound editor later if necessary.

In a loud situation or with heavy bass, you do have to prevent the preamp from overloading, either with an attenuator or going mic-battery box-Line In. But that's for loud, amplified music with serious low frequencies, not a classical ensemble.

Unamplified classical music is far less likely to overload the preamp. You should have no problem recording an orchestra or chamber music going directly from mic into Mic-in--I've done it. You will, however, get equal fidelity from the music and from the coughers, the program rustlers and your own movements.

[RockyJ]

A440, the live recordings sub link to music doesn't work for me, it just sits there and eventually says it can't be displayed. The gallery section works but not the live recordings link.

How is the economy model of core-sounds' cardioids? Have you heard?

[A440]

How is the economy model of core-sounds' cardioids? Have you heard?

You're right about the gallery link--give it another try sometime and PM Kurisu if it's still stuck.

The economy Core Sounds (Low Cost Cardioids) were the ones I had and eventually sold. I didn't like them. Well-built, yes; crisp, yes; rich, no. The effect was a little metallic. They just didn't sound as musical as my ultra-basic omni Sound Professionals BMC-2s. If you look at http://www.taperssection.com , where the extreme recording fanatics dwell, the Low Cost Cardioids don't have a good reputation there either. You'll have to extract another Benjamin from your wallet for serious cardioids.

By the way, if you want to hear bad bass roll-off and/or tinny cardioids--hard to tell what the culprit is--try the samples here:

http://www.giant-squid-audio-lab.com/gs/gs...y1.html#samples

They think those sound good?

[RockyJ]

now I'm looking at microphonemadness cardioids that reach 20-20k. Have you heard about those. I still think cardioids will be the way to go, but I'll probably end up having them both sooner or later.

[A440]

I've never had a pair of those, though the specs look very promising. They do have a 30-day guarantee--want to be the guinea pig?

Just looking at them, I'd be a little wary about getting the ones with the croakie mounts that slip onto your eyeglasses. Next to your ears would be an optimum spot, but because cardioids are directional, your sound might swing around every time you turn your head. Better to get a pair with clips and put them someplace raised but less mobile.

Edited February 13, 2006 by A440

[RockyJ]

I'm having a hard time getting off my idea of going to cardioids for acoustic music in halls, so I'll probably be the guinea pig since these reach to the 20h.

Good idea on the clips but I usually will be facing the stage and I figured those would be the least problem area for body movement noise rather than shirts or lapels.

[A440]

Glad you're giving them a try. It will be great if you can report back on your results and post some samples.

[RockyJ]

I posted my first recording. Being newby my level was too high and I couldn't see the meter on my sony rh910

[A440]

Where did you upload to?

[greenmachine]

It's hidden in the depths of the gallery, category theatre and spoken word, here:

http://forums.minidisc.org/index.php?act=m...album&album=209

The first example appears to show the for cardioids typical nasal, dimensionless sound. RockyDisc, if you have the chance to share different recordings / kinds of music for evaluation from time to time, we'd appreciate it. Thanks for sharing.

[RockyJ]

It's hidden in the depths of the gallery, category theatre and spoken word, here:

http://forums.minidisc.org/index.php?act=m...album&album=209

The first example appears to show the for cardioids typical nasal, dimensionless sound. RockyDisc, if you have the chance to share different recordings / kinds of music for evaluation from time to time, we'd appreciate it. Thanks for sharing.

It sounds pretty much like the original. The singer did have a higher timbre then a lot of sopranos. The cardioids are advertised as 20-20k. I'll have to post some more louder stuff that isn't clipped. Also I need a remote so I can try and level the sound but I really think there will be no way except by dead reckoning and setting it at a best guess. I wish they would just have a little red light that flashed on clip. That would be better then those lame bars on the Sony.

But I did get some Panasonic mics and will try your DIY. The 61B mics have little tabs sticking out, should I attempt to solder only to those in order to keep the heat down.

I worry my soldering with my 25 watt iron may get it too hot.

[CHURCH-AUDIO]

To understand why some mics with different polar patterns pick up low end better then others you have to understand wave forms.

Low frequency is a long wave form 50 Hz takes 23 feet approx before it is a fully developed wave form so. What we know from this is frequency’s below aprox 200hz are Omni directional in nature ( non directional ). So omni mics tend to pick up low frequency much better then Cardioid mics do. One of the other problems with cardioid mics is they operate on phase cancellation to derive directionality. The ports on the back of a cardioid mic are in fact 180 degrees out of phase from the front of the cardioid capsule thus giving the cardioid mic directionality. There for some wave forms get canceled some get reinforced. Thus cardioid mics tend to not be Flat in frequency response they tend to have a rise in high frequency and a gradual rolling of at low frequency’s. Good cardioid mics use various methods to reduce the nasty effects of phase cancellation and try to improve low frequency by tuning the front and back of the capsule also re-tensioning the capsule helps.

Increasing the output of the mic is one way around this problem because of the Fletcher Munson curve the louder a sound gets the more high end it seems to have, the lower a sound gets the softer the high frequency is. So if we increase the sensitivity of the mic we can in fact capture more low frequency’s even with a cardioid mic. The only problem is that there is a limit to how much you can increase sensitivity and still how low distortion. So if you want to capture sounds exactly as they happen an omni is good, but it will pickup reflections from all surfaces. Some will reinforce the sound nicely some with cause phase cancellation. Cardioid mics do not have this problem as much because they are directional and can be pointed at the source in order to understand the benefits we have to understand phase cancellation.

Phase cancellation is simple its two frequency’s that arrive at the microphone at the same time, with the same amplitude and the same wave length and in phase with one another. This last bit is complicated. In phase with one another means that both signals are positive or negative going with respect to one another when they enter the sound ports of the microphone or ear in question. So with omni mics phase cancellation is much more likely to happen. That’s why we have the jecklin disk its a boundary between two omni mics that prevents phase cancellation. It creates a boundary or separation between two omni mics and causes them to be less interactive with one another. Thus less likely to have phasing problems between each other and more likely to produce a good stereo image.

I would like to write more about complex subjects of audio if anyone is interested in my knowledge that I have gained being a sound engineer for the last 20 years I would love to share it

Chris Church

Church Audio

I will be recording orchestra and unamped vocal recitals. Sometimes from 5 rows back sometimes from back row.

Are the cardioids that noticeably 'tinny' as I have read or are they just not picking up the higher energy base from the sides of the theatre walls and such. Do they actually distort the sound?

I'm wanting to talk myself into cardioids to minimize theatre sounds. In an amped environment the audience and bounce effect are overpowered but not so in acoustic settings, but I don't want to lose bass.

and second question.

Why would I need bass roll off in omnidirectional's. Can't I just edit the sound file in my Goldwave editor.

[RockyJ]

Is thermal noise an issue with recording? After all we wear the mic next to our temple and often have the recorder in clothes pockets.

[CHURCH-AUDIO]

I am not sure what you mean about thermal noise?

the definition is the thermal agitation of electrons in a conductor also called Johnson noise. You might be confusing this with static dischage easly fixed by using good cable

This also refurs to noise generated by a semiconductor when it gets heated. I do not see the connection there. The other type of noise is Inducted noise from badly sheilded capsules when placed close to the body. But that can be eliminated by good sheilding. The other noise of the clothes and being close to the head is a simple fix make sure the source is louder then you are . Then the noise you make will be several db down from the source being recorded. Even though you have the " inverse square law " working agenst you, this law states that, in very simplistic terms. Relaying to the field of sound the closer we get to a source the louder it is. So when you are wearing mics if you have your gain control cranked you are going to pickup more of you and less of your recording. How ever if you are say putting out 60db and what your trying to record is putting out 90db from where you are seated you will pick up the source and be 30db down from the 90 db. Thus less likly to pick it up move ten feet closer to the source your trying to record and you will be at 93db aprox, depending on directionality of the source. You might be 95 db its simple and most people know about it but few understand why. Look at sound waves from a band OR any sound source as a giant sphere. The closer you get the the sphere the closer you are to the core, the closer you are to the core the orginator of the signal the louder it is. This is a law of phyiscs and can not be changed. Some speaker companies use extreme directionality to minimize this effect and create a loud sound field further away from the core. But all sound is subject to the friction of air particules. These particules slow down the sound wave and reduce its power thus the further you are away the lower in volume or amplitude the sound wave becomes. Also temperature and humidity and sea level effect the distance of a sound wave will travel and its speed.

Chris Church

Church Audio

Chris Church

Is thermal noise an issue with recording? After all we wear the mic next to our temple and often have the recorder in clothes pockets.