A question about room reflections

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hemmick reef

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My question, hope it's not too silly but I have been wondering about this for a while:

I put an amp in the corner of a room on the clean channel and a microphone several feet away to pick up the ambience.

1. I play the guitar through my amp quietly and record the sound.

2. I turn the amp up a notch and record again, and repeat this until I can't stand the volume any more.

The change in volume affects the reflections and causes a dramatic change in the sound.

I then go through the same process but put the mic in front of the amp and subdue room reflections and ambience but use a synthetic reverb instead.

Can I get that same effect from a synthetic reverb, or is it fixed with this parameter, and based on just a good signal entering the soundcard converter whatever the volume of the sound?

I hope my question makes sense.
 
When you record a sound direct (D.I) into a computer you aim for the hottest signal without clipping. When you then add synthetic reverb I don't think you can vary the chaos effect of a louder sound recorded through a mic in a room.
If you make the synthetic reverb 100% wet with a D.I'd guitar how can I increase the effect of turning the volume up as you could with an amp & mic in a room, a synthetic reverb must have a fixed parameter for this.


Ok the amp has been moved away from the wall.
 
hemmick reef said:
When you record a sound direct (D.I) into a computer you aim for the hottest signal without clipping.
Click to expand...

umm....no you don't. recording levels apply to all instruments equally.


hemmick reef said:
When you then add synthetic reverb I don't think you can vary the chaos effect of a louder sound recorded through a mic in a room.
If you make the synthetic reverb 100% wet with a D.I'd guitar how can I increase the effect of turning the volume up as you could with an amp & mic in a room, a synthetic reverb must have a fixed parameter for this.
Click to expand...

set up the reverb as an aux send. by turning up the amount you send to the aux (and thus to the 'verb unit) you'll increase the wet:dry ratio.


seems to me you don't really understand the 'verb's parameters. i suggest you consult the manual for this.
 
I'm not articulating this correctly :(

I'll try again.

Once I have recorded a D.I.'d guitar into cubase I can then add my reverb. I can make it 100% wet. But I cannot change the characteristics of making the guitar sound like it has been recorded at a louder volume in a synthetic room, which has nothing to do with wetness or dryness of reverb.
 
hemmick reef said:
I'm not articulating this correctly :(

I'll try again.

Once I have recorded a D.I.'d guitar into cubase I can then add my reverb. I can make it 100% wet. But I cannot change the characteristics of making the guitar sound like it has been recorded at a louder volume in a synthetic room, which has nothing to do with wetness or dryness of reverb.
Click to expand...
OH, you're just joking around, right??? Very good, you got us, we fell for it. The old "I'll ask the stupidest, most mixed-up, senseless question I can, and watch these idiots try to answer it". Well done.

Now go away, earth is full.
 
RAMI said:
OH, you're just joking around, right??? Very good, you got us, we fell for it. The old "I'll ask the stupidest, most mixed-up, senseless question I can, and watch these idiots try to answer it". Well done.

Now go away, earth is full.
Click to expand...

Well it may seem a stupid question to you. But it was an honest question, something I didn't quite understand about reverb, something I was trying to clear up about acoustics. I had hoped this is one reason for these forums so that people learning (stupid questions permitted) could ask from more experienced users?

I am sure somebody out there with some deeper understanding about acoustics may have a more technical answer instead of the comment above.....please.

If not ignore this post.
 
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hemmick reef said:
Can I get that same effect from a synthetic reverb, or is it fixed with this parameter, and based on just a good signal entering the soundcard converter whatever the volume of the sound?
Click to expand...
It depends upon your definition of "the same effect". In order to duplicate the exact same effect, you'd need the lind of reverb that does "room modeling"; i.e. one that allows you to define the dimenison of the synthetic room, the placement of the source within the room, and a good approximation of the reflection characteristics of the room. There are such reverb plugs available.

Otherwise, the effect can probably be somewhat approximated with a more standard reverb by tying volume automation to effects automation.; i.e. set up your automation bands in a DAW editor so that as you raise the volume automation you also raise the wet/dry mix of the reverb.

G.
 
hemmick reef said:
When you record a sound direct (D.I) into a computer you aim for the hottest signal without clipping. When you then add synthetic reverb I don't think you can vary the chaos effect of a louder sound recorded through a mic in a room.
.
Click to expand...


You know when you go to Starbucks and order coffee, and they are like "do you want room for cream?"

Dude..there is no room for cream if you go for the hottest signal when you track!!!!
 
stash98 said:
Dude..there is no room for cream if you go for the hottest signal when you track!!!!
Click to expand...
You sure because cream always had room for reverb?
 
hemmick reef said:
My question, hope it's not too silly but I have been wondering about this for a while:

I put an amp in the corner of a room on the clean channel and a microphone several feet away to pick up the ambience.

1. I play the guitar through my amp quietly and record the sound.

2. I turn the amp up a notch and record again, and repeat this until I can't stand the volume any more.

The change in volume affects the reflections and causes a dramatic change in the sound.

I then go through the same process but put the mic in front of the amp and subdue room reflections and ambience but use a synthetic reverb instead.

Can I get that same effect from a synthetic reverb, or is it fixed with this parameter, and based on just a good signal entering the soundcard converter whatever the volume of the sound?

I hope my question makes sense.
Click to expand...

When you crank up an amp you're not just hearing the increased reflections. You're also hearing the amps electronics and speakers working harder and more air is being moved in the room. You can't simulate that with reverb.
 
TravisinFlorida said:
When you crank up an amp you're not just hearing the increased reflections. You're also hearing the amps electronics and speakers working harder and more air is being moved in the room. You can't simulate that with reverb.
Click to expand...

Ahh! Getting somewhere now. Thanks TravisinFlorida, that makes sense. :)
 
NYMorningstar said:
You sure because cream always had room for reverb?
Click to expand...
Ooooh, now THAT's clever AND funny! :D :D :D :D

For those kids too young to get it: Cream = Eric Claption, Ginger Baker & Jack Bruce
- - -
As far as the lack of headroom/cream issue, once it's in the box the baseline gain for the git track can always start a few dB down, even if it is recorded hot. That'll leave plenty of room for the wet stuff. Besides, with the situation described, you probably would want seperate tracks for the git and the verb anyway, returning the stereo room model on a stereo track.

But even before that, even when coming in DI, you probably are better of NOT tracking as hot as possible without clipping (assuming you're tracking at 24bit.) That would mean coming into the analog side of the converter at something like +14 to +18 over zero. There's really no need to drive it that hot, there's still plenty of dynamic range to work with, and that in fact can serve only to boost the instrument noise levels.

G.
 
I totally missed the Cream reference when it came to the band. It now makes sense. Great band obviously.

Im tracking my guitars in at -10 or so. When I mix rock, my kick is usually peaking at -10, and the geetars are around -20ish after EQ, comp..etc. I just dont see the need to track hotter then -6db anymore.
 
Another thing about room reflections is that if you have an amp cabinet that's in a corner, on the floor, you're going to get something called early reflections from all the surfaces the speakers are close to. It's an exaggeration of bass that probably won't sound very good. To reduce the effect, you'd get the cab a few feet away from the walls and floor. Once you've done that, a close mic on the cab (eg. within a couple of inches from the grill cloth) should minimize the effect of the room in the recording. This is near field mic placement.

If, when you mic the cab, you place the mic farther away from the cab than the size of the cab (eg. 3 or 4 feet) you're getting into something called far field mic placement where the room comes into play a lot more. So, if you're in a room that naturally produces a good reverb sound (generally a large-ish room with fairly high ceilings and lots of reflective materials or hard surfaces like wood or glass) it will be picked up by the microphone. If the room does not produce reverb on its own (covered in foam or carpets or heavy curtains) it ain't gonna happen. You can check by yelling or clapping your hands etc... and then listening for any kind of reflection afterwards. This will tell you if the room is live or dead.

Small rooms usually have all kinds of acoustic problems that make them unsuitable for a reverb sound.

Be careful with this one so you don't damage your hearing: if you place your ear anywhere in the room or in front of the cabinet exactly where you plan on placing a microphone, you should get a good rough idea of what the recorded sound will be like. (if your head is 3 feet away from the mic, you and the mic will hear 2 different sounds) Acoustic phenomena like standing waves, nodes and nulls will change the response of the room pretty much everywhere.

Now if you record with more than one mic on the cab (eg. 1 close mic and 1 mic around 3 feet away) you get into a couple of different effects: delay and phase cancellation. The sound takes (very little) time to travel, so each mic is not getting the sound at the same time. The difference is only milliseconds, but there is still a delay which can have a cool effect sometimes. This can also cancel certain frequencies, so be aware that moving one of the mics by an inch or so can drastically change the sound when both mics are blended together.

So yeah, delay and reverb can be added to a direct signal to emulate room characteristics. It won't sound the same as a good room, but I think the effect you're talking about is actually delay. A slapback delay effect (no repeats) of a few milliseconds (up to 15 or so if you want to experiment, it shouldn't be enough to separate the sounds, like an echo) added to a dry source like the close mic on the cab can give a sort of thickening effect to the sound. (It doesn't have to be a guitar sound, it works with anything.) It's probably not a great idea to do this all the time, but it might sound cool sometimes. Adding a second mic won't be exactly the same, but it's similar. And a well cranked amp with good eq settings for recording should give you a sound that's very difficult to get from a direct recording.


Make any sense?

sl
 
snow lizard said:
Another thing about room reflections is that if you have an amp cabinet that's in a corner, on the floor, you're going to get something called early reflections from all the surfaces the speakers are close to. It's an exaggeration of bass that probably won't sound very good. To reduce the effect, you'd get the cab a few feet away from the walls and floor. Once you've done that, a close mic on the cab (eg. within a couple of inches from the grill cloth) should minimize the effect of the room in the recording. This is near field mic placement.

If, when you mic the cab, you place the mic farther away from the cab than the size of the cab (eg. 3 or 4 feet) you're getting into something called far field mic placement where the room comes into play a lot more. So, if you're in a room that naturally produces a good reverb sound (generally a large-ish room with fairly high ceilings and lots of reflective materials or hard surfaces like wood or glass) it will be picked up by the microphone. If the room does not produce reverb on its own (covered in foam or carpets or heavy curtains) it ain't gonna happen. You can check by yelling or clapping your hands etc... and then listening for any kind of reflection afterwards. This will tell you if the room is live or dead.

Small rooms usually have all kinds of acoustic problems that make them unsuitable for a reverb sound.

Be careful with this one so you don't damage your hearing: if you place your ear anywhere in the room or in front of the cabinet exactly where you plan on placing a microphone, you should get a good rough idea of what the recorded sound will be like. (if your head is 3 feet away from the mic, you and the mic will hear 2 different sounds) Acoustic phenomena like standing waves, nodes and nulls will change the response of the room pretty much everywhere.

Now if you record with more than one mic on the cab (eg. 1 close mic and 1 mic around 3 feet away) you get into a couple of different effects: delay and phase cancellation. The sound takes (very little) time to travel, so each mic is not getting the sound at the same time. The difference is only milliseconds, but there is still a delay which can have a cool effect sometimes. This can also cancel certain frequencies, so be aware that moving one of the mics by an inch or so can drastically change the sound when both mics are blended together.

So yeah, delay and reverb can be added to a direct signal to emulate room characteristics. It won't sound the same as a good room, but I think the effect you're talking about is actually delay. A slapback delay effect (no repeats) of a few milliseconds (up to 15 or so if you want to experiment, it shouldn't be enough to separate the sounds, like an echo) added to a dry source like the close mic on the cab can give a sort of thickening effect to the sound. (It doesn't have to be a guitar sound, it works with anything.) It's probably not a great idea to do this all the time, but it might sound cool sometimes. Adding a second mic won't be exactly the same, but it's similar. And a well cranked amp with good eq settings for recording should give you a sound that's very difficult to get from a direct recording.


Make any sense?

sl
Click to expand...

Yes it does, thanks.

When recording using just one mic about 3-4 foot from the amp with a clean guitar sound, what sort of volume should I set the amp at; is it about just choosing a volume that sounds right in the room?
 
Don't worry so much about volume: worry about the tone you're getting regardless of volume! If it's a tube amp, it'll probably sound better at a higher vs. lower volume. If it's solid-state, it really won't matter much.

That's my view anyway
 
Reef,

First, let me say you asked a relevant and meaningful question. Real-world room acoustics and reverberation is a very complex issue to deal with, let alone understand. You did real-world research. Well done.

Take this example:

A choir sings in a large acoustically treated room. When they sing quietly, there appears to be little or no room effect. As they sing louder, not only does the effect of the acoustical environment become apparent, it changes in color, decay time, primary reflection, secondary reflections, etc. This change is based on the volume alone. What sounds glorious at full volume may sound lacking at quieter ones. This is difficult, if not impossible to achieve using artificial reverb. Typically, what you will notice when you send less (or more) signal to an artificial reverb is more or less of an effect that sounds very nearly the same.

Though more easily controlled and more flexible than a real room, reverb systems that do not do a very, very good job with room modelling do not emulate real spaces well, if at all, though they may very well produce a reverb that suits your purpose.

Also, when you record direct (or miced for that matter), do attempt to set levels that utilize the full resolution of the medium. That is, set your inputs such that the loudest signal from the instrument will not produce an over, but will come as close to 0 as is reasonable. There is no reason to leave room for cream, sugar, cinnamon, etc. as effects will be added during mixdown to another track.

People that don't take advantage of the recording medium are like people who crop digital pictures. The old saying goes "don't waste pixels". In photography, lost resolution is seen, in recording, it is heard. This is one more reason to record at 24 bit vs 16. More resolution, i.e. you can afford to lose a little during processing.

So, to the boneheads that said you asked a stupid question, I would say get out more and do a little research before calling someone else stupid. :cool:

Best wishes,

Poco
 
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