When you place a mic in front of an absorbent material like fibre glass, there is obviously no reflections to speak of. If you were to take this mic, (especially an omni) and move it into the room, reflections will reach the mic from the walls, exposed areas of the roof, floor-to-wall-to-mic, etc.
Three things are happening here.
First, the sounds that are reflected are changed based on the type of material in question. Thickness, density, surface finish are all factors.
Secondly, it will take a sound longer to reach the mic via a reflection, than it would to go directly to the mic. Some of these reflections could even be loud enough to change the timbrance of a sound.
Lastly are phase issues. When one of these reflected sounds do reach the mic, they may be at a different phase angle than the source sound. If, you have one frequency at 180 degrees to the source, you will get frequency cancellation at varying amounts depending on the amplitude.

When you place the mic way up at the roof, you are not eliminating these phoenomena from the mic, as they are always at work. The appearance of these things are, as you've noticed, much less pronounced.

:) Hi Ted and Steve, I would like to hear the sound you got somehow Ted.

In the 70's, close micing was needed to prevent instrument bleed when multitracking was really taking off. The practice has continued to present. A lot of mic designs were developed to work with close micing, like bass roll off switches and extra padding.

If you look at some of the studio pics from the old time radio days, 40's, 50's, and early 60's, you will find that the rooms were designed to work with a few mics, and that instruments and singers were placed in strategic locations within the room to achieve the balance. Under nice quiet conditions, your sound, with the help of a treated area, like your ceiling would be pleasing.

--Rick

When you place the mic way up at the roof, you are not eliminating these phoenomena from the mic, as they are always at work. The appearance of these things are, as you've noticed, much less pronounced.

I figured reflections they were still at play, but minimized by this approach. Since I'm playing "up" towards the mics, behind which are my absorbers, maybe there are fewer reflections heading back down to the floor than when playing facing one of the long parallel walls in my room. In the end, I know there's no substitute for a good room, having played in a few, but knowing this technique for capturing a live sound in a crappy room with treatment is useful when I don't have access to a better room.

Rick: having close mic'd lots of acoustic guitar and then overdubbing vocals on top of it for years, I've taken to capturing the live thing, with all the faults, flats and sharps. My wife heard a scratch take of a song I did and wanted it over the overdubbed version. When I asked why, she claimed it was more real and therefore more moving. It kinda got me thinking about the whole recording thing and I got into investigating the binaural recording thing and found a pretty good in-between technique of ORTF omni's which don't loose much as much in mono as with cardiods.

When I get a solid take of The Newry Highwayman I'll slap it up on my web site and you can listen. But don't hold your breath: I'm a hack hobbyist with insufficient practice time (standard disclaimer).

If nothing else you'll get to hear what a Larrivee sounds like in a shoebox room with treated ceiling and walls, untreated vynl floor, through some SRO's in ORTF through an RNP and into a Korg D1200.... along with my yodeling of course. :)

thanks to both of you. this whole hobby continues to challenge and delight me.

Cool. :D :D
:c:
good luck, Steve

Ted,

> it sounded fantastic. I was floored. <

That's always good to hear. :D

Besides avoiding short delays from a nearby surface, there's another factor that can help or hurt: Acoustic instruments that have a resonating box, like a guitar or cello, radiate different frequencies in different directions. This is one reason close miking string sections, cellos, and acoustic basses often gives poor results.

For example, if you close mike a double bass you get only part of the spectrum. Too trebly near the bridge, too muddy near the F holes, and so forth. When you pull the mike back a few feet you pick up more of the total sound. So in your case one factor is the directional properties of your particular guitar.

--Ethan

Ethan,
I`m just finishing my room ( i mean, the acoustic treatment) with your bass trapps and absovers, looks great! and i hope sounds in the same way... :D ...i`ve been thinking about the ceiling clouds made of rigid fiber and fabric...my floor is made of granite, and reading this post, i thought, will work without carpet? i want bright guitars too :D and brighter drum sounds...what do u think? :roll:

Aziel,

> will work without carpet? <

Yes, a reflective floor is best.

Look at the million dollar studios on any cover of Mix magazine. You never see carpet on the floor in the live room.

--Ethan

Look at the million dollar studios on any cover of Mix magazine. You never see carpet on the floor in the live room

Good point, but, remember, my room its a little rectangular room...it doesnt matter? :roll:
will i have some reflections?

i mean...BAD reflections...ringing and that kind of stuff... :D

Aziel,

> my room its a little rectangular room <

When the floor is reflective you need a ceiling that's either fully absorbent or very high. There is no difference acoustically between a ceiling that's absorbs 100% and one that's infinitely high.

--Ethan

There is no difference acoustically between a ceiling that's absorbs 100% and one that's infinitely high

that`s really interesting... :)

Aziel,

you do exactly what you see mentioned above, install rigid fiberglass panels.

Leave them down from the ceiling (air space between the ceiling and the insulation) and suspend them.

Voila - a sound absorbent ceiling.... very dead.... great sound.

Rod

How many clouds and what size i need to get a good covering of the ceiling with the clouds? my room is around 4 meter wide X 3 meters :roll: