Room sound when direct micing

[NL5]

Ok, as to not hijack the poor dude in the other thread any longer, I decided to do a little test. (and since I am HORRIBLE at explaining audio in English) I took a snare and clamped a mic to it and locked it into position. Then I took the snare and randomly placed it in three different spots in two different rooms. The theory being that the initial hits (not the room echo) will sound exactly the same since it is close miced (1 inch from drumhead). They are in three sets of ten, please comment on any similarities or differences you hear, or if the all sound the same.

I apologize in advance, as I'm not a drummer, so I just hit single hits as evenly and as well centered as possible. The snare itself need new heads and tuning, so please don't comment on the sound of the snare, just if the y all sound the same, or if there is some differences and how much different?

Thanks.

Http://www.lightningmp3.com/upload/drumtest.wav

 

[NL5]

Anybody????

 

[JuliánFernández]

Thanks for sharing...

I can clearly hear the difference... If you hear the first ten, and then the second ten hits you fell that the snare was retuned for the second 10 hits...
It sounds like natural eq for sure...

ITOH, I´m not sure how much it would change with a drummer hitting hard on a tuned snare... I don´t think that the change would be huge in the context of a mix... What do you think?

 

[mixsit]

Yes there is at least one big difference -on cheap plastic speakers at very low volume I can hear a very big difference with the amount of ring being much stronger in the first set vs the second two. I'd bet that (biggest) variation is in how it's hit. (like maybe 1st set is less 'center hit' than 2 and 3?

 

[NL5]

Yes there is at least one big difference -on cheap plastic speakers at very low volume I can hear a very big difference with the amount of ring being much stronger in the first set vs the second two. I'd bet that (biggest) variation is in how it's hit. (like maybe 1st set is less 'center hit' than 2 and 3?

Nope. They are hit as near to exact as I could. If you listen, the set of 10 are VERY consistent, and I can tell you that each set was hit 99% the same. It's the room changing the sound. Which is pretty amazing when you consider a snare hit lasts only about 40 ms. Of course, no matter the room, you get reflections starting at about 4ms.

There are two other huge differences that nobody has mentioned yet, I wait a bit before I point them out. I'm sure once pointed out, they will be pretty obvious.

 

[mixsit]

Nope. They are hit as near to exact as I could. If you listen, the set of 10 are VERY consistent, and I can tell you that each set was hit 99% the same. It's the room changing the sound. Which is pretty amazing when you consider a snare hit lasts only about 40 ms. Of course, no matter the room, you get reflections starting at about 4ms.

Interesting, and I agree the hits within the set' are consistant enough. BTW since I'm comming in late to the party , what is the other thread/subject?
Thanks, wayne.

 

[NL5]

Interesting, and I agree the hits within the set' are consistant enough. BTW since I'm comming in late to the party , what is the other thread/subject?
Thanks, wayne.

It's one of the guitar sound threads. People were claiming that the room is irrelevent when close micing a guitar. If the room is changing the sound in a 40ms burst, imagine having 100db of continuous sound. It's gonna wreak havoc all over a room - way more than in a single drum hit.

 

[Zaphod B]

I can easily hear the room ambience when I close-mic my guitar amp. I can't imagine anyone saying that you can't hear it, unless you are in a completely dead room.

 

[TylerDrums109]

Ok, as to not hijack the poor dude in the other thread any longer

Its all good =]

 

[NL5]

I can easily hear the room ambience when I close-mic my guitar amp. I can't imagine anyone saying that you can't hear it, unless you are in a completely dead room.

Yep. Most people swore it had no effect. And, BTW, there is no such thing as a dead room save for an anechoic chamber. Dead rooms will reduce the amount of reflections, especially in the highs, but you will still have nodal effects and some comb filtering. It's virtually impossible not to. Plus, the room sound put's "life" into a track. It's a good thing, and is why Russ Berger stays in business.

 

[DrewPeterson7]

It's one of the guitar sound threads. People were claiming that the room is irrelevent when close micing a guitar. If the room is changing the sound in a 40ms burst, imagine having 100db of continuous sound. It's gonna wreak havoc all over a room - way more than in a single drum hit.

I can't pretend to have tried this, and to be perfectly honest after reading this thread (no speakers here, sorry) I'll certainly consider the possibility and maybe do an experiment or two myself...

But, that said, I think the "100db of continuous sound" might be WHY I would expect it to be less of a factor. A snare is a single hit, not really that hugely loud in the grander scheme of things, and has a sharp attack and then a fast decay - after the first few milliseconds, there's not much sonic energy coming off the snare, which means the reverberations in the room have very little to compete with.

100db of continous sound, meanwhile, is a constant 100db roar right into the mic. It's LOUD. It's drowning out everything around it because, room sound? What room sound? You've got 100dB right in your face.

That said, I've also heard anecdotal evidence that this might not be true - Petrucci swears by the sound of an SM57 and a E906, I think, right up against an amp centered in a large room, and claims it doesn't sound right unless the room is at least a certain size. This is a man whose tone I both happen to really like, and who's spent the last 20+ years in recording studios, and he and his band have increasingly taken a larger role in the recording process - i.e, not someone I'd discount out of hand.

So, there's only one thing I can conclude here - we have to get some poor sucker to actually try this.

Could anyone suggest a good, reliable (and, prefferably, low cost or free) way to affix a SM57 to a cab while moving it around that wouldn't interfere with room reflections but would also ensure that the cab and the mic were in the exact same orientation for each clip? I'm thinking some sort of mic stand clip or something, but...

 

[Zaphod B]

Yep. Most people swore it had no effect. And, BTW, there is no such thing as a dead room save for an anechoic chamber. Dead rooms will reduce the amount of reflections, especially in the highs, but you will still have nodal effects and some comb filtering. It's virtually impossible not to. Plus, the room sound put's "life" into a track. It's a good thing, and is why Russ Berger stays in business.

Agreed.

When I first started doing home recording I was going direct through a Pod XT Live and did not have any room ambience dialed in (a very cool feature on that modeler, BTW). The guitars - and the rest of the recording - sounded flat and lifeless, even with hall reverb or a delay added in the board.

My recording space, AKA my bedroom, has a good mix of reflective and absorptive surfaces - hardwood floors, hard walls, and wood furniture but also rugs and a big-ass bed and clothes and crap laying around. So the end result is a pleasant ambience when I'm micing the amp. It's a sound that you would think would get lost in the mix but you can definitely tell when it's not there. I'm not the least bit tempted to try to isolate the amp.

 

[NL5]

But, that said, I think the "100db of continuous sound" might be WHY I would expect it to be less of a factor. A snare is a single hit, not really that hugely loud in the grander scheme of things, and has a sharp attack and then a fast decay - after the first few milliseconds, there's not much sonic energy coming off the snare, which means the reverberations in the room have very little to compete with.

100db of continous sound, meanwhile, is a constant 100db roar right into the mic. It's LOUD. It's drowning out everything around it because, room sound? What room sound? You've got 100dB right in your face.

No offense, but your logic (and understanding of physics) is back asswards.

A snare hit lasts 40ms, with the bulk of the sound in the first 20ms. Which means no reflections past about 10 feet can get into the initial sound of the strike. The first sample is in a 28X36 room with 12 foot ceilings (with very little parallel surfaces), so it's only picking a up a few reflections. The second room is 10X12 with 8 foot ceilings, so all first reflections are hitting back to the mic in the first 20ms, and many second, third, fourth, etc. reflections Also, an snare hit is much louder than a guitar amp. Just very short duration.

Now, with a guitar amp blaring at 100db not only are you going to have all the same reflections, you won't have the benefit of a "zero reflection" time. Even though the snare's is only about 4ms (2x the distant in feet from nearest surface - usually the floor), it is still there. Also, you are going to get much more severe peaks and nulls, and hellacious comb filtering. Have you ever walked around a room while you're playing? Notice how it get louder in spots, and softer in others. Sounds brighter in spots than in others. If the room is bad, the swings can be 30+db. That's the room!

I wish I was better at explaining things on the interwebs, but alas, english is not my strongest language. But hopefully you can understand that a single close mic'd snare hit will be much less effected by the room than a blaring guitar amp. If not, it should at least demonstrate how much the room effects a close mic'd source. i really see know way to deny such blatant audio evidence.

Edit - I'm also curious as to how people think the ratio of teh amp to room is going to change dependent on volume? The louder the direct signal, the louder the reflections, no?

 

[DrewPeterson7]

Now, with a guitar amp blaring at 100db not only are you going to have all the same reflections, you won't have the benefit of a "zero reflection" time. Even though the snare's is only about 4ms (2x the distant in feet from nearest surface - usually the floor), it is still there. Also, you are going to get much more severe peaks and nulls, and hellacious comb filtering. Have you ever walked around a room while you're playing? Notice how it get louder in spots, and softer in others. Sounds brighter in spots than in others. If the room is bad, the swings can be 30+db. That's the room!

Yes, but it's 1.) the room from 5-15 feet back, and 2.) also a product of the orientation of your head relative to the speakers.

Either way, I think you misread me - in a sentence, my post was "this is the typical argument that a room shouldn't impact the sound of a close-mic'd guitar in a fundamental manner; that said, if you want to find out someone really should do this same test with a cranked-up guitar amp, so could anyone suggest a good way for me to attach a mic to my cab in such a manner that it won't get re-positioned if I move the cab?"

I'm saying you just might be right, but the transient response of a snare and that of a guitar amp are just too different for that to be a fair comparison.

 

[NL5]

I'm saying you just might be right, but the transient response of a snare and that of a guitar amp are just too different for that to be a fair comparison.

Absolutely. The snare hit should be WAY less effected by the room. There are no standing waves, really just one pulse of reflection, not continous chaotic reflections. Besides, the original contention was that the room has no effect on close mic'd sources (or so little as to be of no consequence). There are obvious differences in my samples.

Yes, but it's 1.) the room from 5-15 feet back, and 2.) also a product of the orientation of your head relative to the speakers..

I don't really understand your first point. You can stand right in front of a cab and move around and the sound changes. 2 really is just emphasizing what I am saying. It's not relative to the speakers, it's relative to the direct and indirect sounds and there particular additive effects at that exact spot. It's happening everywhere in the room, not just everywhere except where you happen to put the mic.

my post was "this is the typical argument that a room shouldn't impact the sound of a close-mic'd guitar in a fundamental manner; that said, if you want to find out someone really should do this same test with a cranked-up guitar amp, so could anyone suggest a good way for me to attach a mic to my cab in such a manner that it won't get re-positioned if I move the cab?"

I'm going to try and do that today or tomorrow, but for sure by Friday. I just need to make sure the cab and mic are locked together, and I'll use the same DI clip and reamp with all the same settings. Drums were just easier, and should be way less effected by the room due to the very short time of a drum strike.

 

[DrewPeterson7]

I don't really understand your first point. You can stand right in front of a cab and move around and the sound changes. 2 really is just emphasizing what I am saying. It's not relative to the speakers, it's relative to the direct and indirect sounds and there particular additive effects at that exact spot. It's happening everywhere in the room, not just everywhere except where you happen to put the mic.

I always understood that to be a proper of the speaker - that the center of the cone tended to emphasize the high frequencies, while the edges tended to emphasize more of the bass. I mean, if you sweep a mic back and forth up against the grill of a speaker, the tone tends to change pretty radically. I've never done this in a perfectly acoustically dead room, but I suspect that since this effect tends to even out a bit as you go further back, this is a property of the speaker more than the room.

Likewise, due to the way sound waves travel, directly in front of the speaker you tend to get more treble, but off to the sides, the lower-frequency, longer wavelength bass frequencies (which tend to be less directional) come out a bit more. Walking back and forth in front of a guitar amp is partly an excersize in room sound and notching, true, but it's also partly about the way sound radiates from a vibrating source.

Either way, I think we're at least in agreement that this is something that we need to test with an actual guitar amp.

I think this is a fascinating thread, by the way.

 

[NL5]

Either way, I think we're at least in agreement that this is something that we need to test with an actual guitar amp.

I think this is a fascinating thread, by the way.

Thanks!

Yeah, I don't agree it's necessary, my point is already valid. But, I just figured out how to do it. I have a rolling bass cab that I put a combo amp, mic stand, and mic on top off, that I can roll around with the amp and mic staying in a pretty locked position. I won't be able to move it as far due to the reamper, but hopefully I can get two or three samples.

I'd take a minute to read up on comb filtering, it will help understand the physics of what is happening better. I am by no means an expert, and have a lot to learn myself, but I think I have a pretty basic understanding of the hows and whys.

 

[Yonce N Mild]

very interesting

A couple of thoughts here. Is it not safe to say that the closer you get to amp with a mic the less room noise you pick up? I have often moved a mic further away to "get more room". Is this flawed logic?
While I don't think it's fair to say that the room has no effect on a close miced amp I think it is fair to say that the effect is reduced the closer you get. Maybe because the ration of direct sound to room noise increases?

 

[NL5]

I have often moved a mic further away to "get more room".

I would agree 100%.

And let me just say, a lot of what I am saying is my opinion, but also based on the physics, and my experience recording. Also, what I may consider a huge improvement, others may consider small, or not even notice a difference. To me this isn't a game of inches, but of millimeters. EVERYTHING matters, and everythings adds or subtracts from the final product.

Anyway, after setting up my guitar cab experiment, I realized I can't roll it around very good by myself, and don't want to dump 4k worth of gear off of it. So, I was only able to do a small test for now. I will not say what I did for this one until after people have weighed in. Do they sound the same? If not, what's different about them?

http://www.lightningmp3.com/upload/guitartest.wav

.

 

[six]

Ok, as to not hijack the poor dude

Good idea. Did you set a link in the other thread? Don't think so.

It's one of the guitar sound threads. People were claiming that the room is irrelevent

IIRC they (incl. me) were mostly saying it doesn't have a "huge" effect as you claimed.

Most people swore it had no effect.

See above...

[...] Is it not safe to say that the closer you get to amp with a mic the less room noise you pick up? [...]
I think it is fair to say that the effect is reduced the closer you get. Maybe because the ration of direct sound to room noise increases?

I would agree 100%.

That's funny, really. I think I basically wrote along the same lines in the other thread and was laughed at...

http://www.lightningmp3.com/upload/guitartest.wav
.

Ok. I must be tone deaf not to hear this "huge" difference.

... and this extra 8th note in the 4th bar really annoys me .