Recording + Reverb

[RatFace]

Hello peeps - I've been experimenting with recording methods and processing, and thought I'd post some results, because they might be useful to others.

 

Basically - I have two options - I can either

 

1. record in a nice big room at work (maybe 20x10m in size). This has a really nice acoustic, with a natural reverb that makes the concertina sound great. I record with the microphone 4-5m away. The problem is that it also picks up the noise of the city (it's a noisy city!), and also the sound level isn't that high, so there's some background hiss even with really good quality recording equipment. I use two mics each pointing 45-60degrees away from me - each mic going to a stereo track (ORTF). This gives a quite spookily realistic sound - e.g. when checking using headphones after the recording you can hear your own footsteps walking towards the mics and you can't help looking up to see who's coming!

 

2. record in a small room (cellar) at home. This has absolutely no acoustic character at all, and the mics need to be close. My recent attempts use one mic each side, pointing almost directly towards each end. Then I mix them with only a slight pan of each (i.e. the left mic pans 10% or so to the left etc). The sound is essentially dead, and needs reverb to make it beareable. The advantage is that the signal to noise ratio is so high even traffic outside is now inaudible.

 

For mixing I've been using n-track studio which isn't free, but is actually pretty good. It has its own reverb plugin, which is all I've used until tonight - I've never thought that it's great, but it can improve the sound so long as it's not used much. If you try to emulate the sound of a big space it gets quite bad. I thought I'd try some others (all free) - basically most from here. I wasn't really expecting much, and apart from one, they're all no better (some much worse!) than n-track studio's builtin reverb.

 

So - the one that is better is called SIR and is an "impulse response simulator". Basically, the acoustics of the room you want to emulate are measured by recording the sound of a sharp impulse (e.g. a gunshot or balloon bursting). SIR implements an algorithm that analyses this impulse response sound, and then applies the characteristics to your input recording. In addition you can adjust the characterstics - e.g. stretching it in time, damping it, changing the balance between the original (dry) and the reverb (wet) parts etc. The quality of the output depends a lot on the quality of the impulse response - you can download various ones (for free!) here. The best I found (though I only tried a few) is the "Chicago Church 1 (Surround!) Impulse set", and this is what I use below in order to try to simulate the completely natural hall recording.

 

So - here is the result (mp3) using the first 25 seconds or so of Rosline Castle repeated 4 times:

 

1. Recorded naturally in my "hall" as above.

2. Recording in my cellar, close microphones, no post-processing other than to mix the two channels

3. The output of 2. passed through the n-track studio reverb unit (Hall2)

4. The output of 2, passed through the SIR plugin (as above) in n-track studio

 

Unfortunately I never end up playing this piece the same, so the comparison between (1) and (2-4) is not exact, but hopefully it's good enough.

 

I suggest you listen through headphones or a decent speaker system (not little crappy ones like sit either side of my computer!) when making the comparison - it's important to be able to hear the hiss/background noise in the first section. My conclusion is that the SIR reverb is pretty good - way better than n-track, and way way better than any other (free) reverb I tried. I only spent 30 minutes or so configuring it too, so I'm sure it could sound even better (the bass is a bit heavy at the moment).

 

I hope some of this may be useful for any others interested in recording at home - even for practicing purposes. If anybody else has got any useful info, I'd definitely be interested to hear!

 

- Danny

[Dana Johnson]

I've done a fair amount of recording concertinas both in good natural acoustic and "flat" rooms that needed some reverb added. Sounds like you have a good hand on the reverb. I use a Digidesign Pro tools set up ( not so cheap ) which works well for me. One thing I have noticed that might be of interest is some stereo miking problems. When you have the instrument close miked, it works pretty well, but you start to pick up more pad and button noise the closer you get. this mechanical stuff seems to go away pretty fast with distance, but as soon as you are a few feet from the instrument unless you have highly directional microphones, you start to pick up both right and left in each microphone. Now when you mix them together, the common portions of the signal start to interfere with each other at frequencies that are various whole number fractions of the wavalength of the spacing between the mics. You end up with comb filtering on the common parts of each signal which can and generally does color the end sound. The degree to which this happens depends on the strength each microphone picks up the opposite channel signal. the louder, the more coloring. You can adjust your mic placement with earphones on the mixed output and hear the difference. Getting just the right spacing can be tricky.

 

I really like natural acoustics if I can find a good space and to record at at least 4 or 5 feet from the concertina to reduce the mechanical noise, but the only decent way I found to make use of it for stereo recording was to set up my microphones essentially coaxially, one inverted over the other but with the diaphrams facing nearly at 90 degrees to eachother ( each one faces the one side of the concertina and the side of the room that reflects most of that sides sound initially.) Now, the sound from any angle reaches both mics at once and the comb filtering is eliminated. You can actually buy good studio mics that are set up like this. The typical consumer stereo mics are so close to each other that this isn't an issue, but if you use two microphones it is something you need to think about.

[David Barnert]

2. record in a small room (cellar) at home. This has absolutely no acoustic character at all...

Ahh, yes. White cinderblock walls, wooden folding chair. We've gotten to know it well.

[Jody Kruskal]

Danny

 

Recording is sure fun.

 

I agree with your assessment of the reverb and room sound. #1 is the best but noisy. #4 comes in second to my ear, good but not as detailed as the real hall. I wonder which church in Chicago was used as the model for the reverb? I grew up there and remember the acoustics of quite a number of churches still. Sound recording is certainly a whole world of its own, thanks for telling us about some cool tools.

 

On the other hand, I found all four of your recordings quite fine to listen to. None of the defects were glaring enough to distract me from hearing and appreciating the artistry of your playing. I’ve always thought that musicianship and performance trump recording values every time.

[Boney]

I'd try #1 with the mics a bit closer, maybe even just half as far. I don't like as much reverb as you have in these, especially #4. It sounds a bit cheezy to my ear, and masks the subtleties in the playing. You can almost get away with it in a tune this slow, but it does come across to me like a "soft focus glamour portrait."

 

You could also try a stereo pair (possibly set up XY) fairly close, and a mic or two a good distance away, mixed in at a low level. I do hear some strange artifacts in the second recording (probably the comb filtering Dana mentioned).

 

Or, try recording quite a bit closer in the hall, and you can always add a hint of artificial reverb later if you want. You can also get very good artificial reverb by playing back a close-miked recording on decent spearkers in the hall, and recording that at a good distance, and mixing it in at a very low level.

 

Here's something that's helped me a lot: after taking a while mixing, don't listen to the result for a while, at least a few days. Then listen again and review your effects levels -- they'll probably sound much more exaggerated than you thought, the ear gets used to effects in long mixing sessions, and it's very easy to get heavy-handed.

 

I also agree with Jody, even with no reverb it sounds pretty good.

[RatFace]

Thanks for the replies everyone - it's interesting to hear the opinions and experiences.

 

Firstly - yes I agree that on reflection the natural/hall recording was probably too distant, especially for "general" use.

 

However - in trying to set up the reverb levels for the subsequent cellar recording I was trying to emulate the hall sound as close as I could with the tools I had - just treating the natural/hall sound as a reference. Listening again now, and swapping between version 1 and 4, I would find it hard to state with confidence (if I didn't know!) that verson 4 is artificial reverb, or even necessarily worse/more artifical sounding than the natural acoustic. To me, it's just slightly different (unlike 3, which is just nasty!).

 

Later on in the original recordings I play a faster piece, and in fact the perception of reverb (both artificial and natural) seems to decrease quite substantially when the tune gets busy, so long as the reverb isn't really excessive.

 

In general I agree that the reverb here is too much though, but fortunately less actually tends to sound less artificial anyway.

 

So far I've been "judging" the sound only using headphones, and also comparing the sound to the two recordings by Dave Townsend. His PoaC recording (which has the best recorded concertina sound ever, in my opinion) actually sounds very close over headphones - obviously a close-microphone recording - I guess because when playing over speakers you get a bit of natural reverb from the room. So - this is perhaps another reason for cutting the reverb down - because it should be "tuned" for normal speaker playback.

 

The next step is covering the walls of my cellar with cardboard* (got to be better than nothing!) to reduce the close/hard reflections, and experimenting with mic positions - I am not sure at the moment whether what sound like phase/comb artifacts are that, or due to being able to hear the noises of an imperfectly set up concertina at close range. Anyway, it will be interesting (and easy) to compare the difference between ORTF and XY, and also between these and my previous one-mic-per-end recording.

 

Jody - unfortunately the download doesn't state the actual church name - just says "Western suburbs". From my one trip to Chicago a few years back, that can't narrow it down much!

 

- Danny

 

* I will keep the folding chair!

[Theodore Kloba]

2. record in a small room (cellar) at home. This has absolutely no acoustic character at all, and the mics need to be close. My recent attempts use one mic each side, pointing almost directly towards each end. Then I mix them with only a slight pan of each (i.e. the left mic pans 10% or so to the left etc).

For certain types of music, I think close miking is best, although your song definitely benefits from the sound of a room. When I close mic (on bandonions & chemnitzers), I use clip on gooseneck condensers at each end, with the element a couple inches from the face of the instrument. This also picks up button noise, but I have a few recordings where it really "works" with the music. Most notable would be bandoneonist Daniele di Bonaventura. If the room is small, it's good to deaden it as ompletely as possible to avoid that "singing in the shower" sound.

 

When mixing the channels, I've found a more natural sound comes from inverting the polarity of the mixed-in channel. I don't know how your software works (I use Adobe Audition, the erstwhile CoolEdit Pro).

 

A typical setting might be (note the minuses):

 

right output = right input - 20% left input

left output = left input - 20% right input

 

With my instruments, I haven't had the levels equal, but for English concertina, I would expect equal levels to work.

 

This method was used for this attempt at one of Jody Kruskal's tunes recorded a few months ago: Gone Fishing

 

I wonder which church in Chicago was used as the model for the reverb? I grew up there and remember the acoustics of quite a number of churches still.

That's an interesting coincidence. Where in town did you live?

[Greg Schneider]

What is the purpose of your recording? Is it for your own personal use? Is it intended for commercial release? If it is the former and not the latter, I suggest not sweating it. Recording is always about sonic compromise. No matter what you may think, there are ALWAYS compromises in the recording process. Even in high budget big label projects. The sonic quality of the performance space, the quality of the mics, the quality of the signal path, your budget, the expertise of the engineer, etc., will all have an impact on the sonic outcome of a recording project. Decide on what areas you are willing to compromise and what areas you are not, and be realistic about the decision. If you can't spend $3,000 (or more) per mic, you're not going to get the best sound, no matter what.

 

I've been a recording engineer working nearly exclusively in classical music for over 21 years. I've dealt extensively with trying to acheiving the best acoustic sound of a variety of instruments and ensembles. Your approach is bascially sound (no pun intended), but you might just consider decreasing the distance between the instrument and the mics. You will increase the signal to noise ratio while preserving the binaural stereo quality inherent in the ORTF pattern.

 

You might also consider using an "H" mic pattern instead. This involves placing the mics in a parallel pattern with the mics three times further from one another than from the sound source (i.e., if the mics are 2 feet from the source, they will be 6 feet from one another). This pattern might also help any sonic problems arising from parallel walls (i.e., out of phase signal).

 

You might also try a co-incident "Y" pattern. This is essentially the same as the near co-incident ORTF, except the diaphragms are placed in as close to the same vertical plane as posssible, rendering the arrival time to both diaphragms as close to identical as possible. (The near co-incident ORTF pattern is meant to mimic the spacing between the human ears, thus replicating the inherent binaural time delay which makes our stereophonic hearing possible.) This isn't as effective at rending a 3D stereo image as ORTF, but it might help.

 

If you are trying to maximize fidelity, forget artificial reverb, because it's all crap. I've worked with many different versions of reverb from C-Sound generated software sysnthesis stuff to high end Pro-Tools plugins and they all suck. You are better off going with a dry sound that is true and accurate rather than adding the tinny sound of canned 'verb. How important is reverberant sound to your final project?

 

Now if you are really after a good natural ambient sound, wait and work up a bunch of material and find an acoustically nice space - maybe a nice chapel - and go and record some stuff there. If you are locked into recording at home you are confronting the reality of the compromise in the recording process I mentioned above; you may have already acheived the best sound that you are going to get in your space.

 

There's nothing better than the sound of a truly lively grand space, but it's not usually convenient for routine recordings in such a place. Decide what is more important, ambient sound or clarity. This may help you maximize the sound that is possible in your recording environment.

 

Good luck. Recording can be a very slippery slope with an endless series of choices, none of them totally satisfying.

 

GAS

[RatFace]

I thought I would continue recounting my experiments

 

Firstly, it was only after my previous posts that I eventually got to hear my recording referenced above through speakers, not through headphones.

 

Yeugh!!

 

Just talking about #4 (cellar recording -> SIR reverb) I really hated it through the speakers (though I still think through headphones it's OK) - the sound is really uneven and jumps around etc.

 

So - I learnt a lesson here - don't trust just one playback system!

 

So, I had another go. This time recording with the mics almost coincident, each at +/- 45 degrees to me, 1.5 to 2m away from me. I also covered the walls with flattened cardboard boxes as much as possible.

 

Regarding the unprocessed result:

 

This resulted in slightly less signal than before, but still plenty. Maybe the tone is better too, since the microphones were pointing well away form the instrument. The other big benefit is that individual notes don't "jump out" like they did before.

 

Initially I mixed these like I'd done for my original hall recording - each microphone going to a left/right stereo channel. However, when I listened through my stereo speakers, I found this was really disconcerting, since the "position" of the sound would jump around quite considerably. It probably wouldn't matter for a duet - maybe OK for Anglo (depending on style - Irish would have the same problem), but made me feel ill after a while! So I reduced the stereo separation by only panning each microphone 50% to each side.

 

I experimented quite a lot with the reverb, aiming for the kind of sound you get in a pub at the end of a session when it's cleared out a bit and you're "warmed up" and have a couple of fancy tunes to get out of your system Previously I'd tried to reduce the amount of the SIR church reverb by shortening it (either attenuating over time, or scaling) - this worked... but at the same time made the sound less natural. In the end I found the best way was to just reduce the gain on the "wet" component (in this case 14dB below the dry/original sound).

 

So, here is the result. It's the same 25 seconds of the same tune. First version is with reverb, second without (i.e. the input to the first version).

 

OK... I should admit that my ears are a bit bunged up at the moment(!), but to me this (version with reverb) sounds identical, perhaps better than the totally natural hall recording - just a bit dryer, and with none of the hiss/background noise. I'd be interested to know what others think - I've obviously listened to this clip far too many times to be objective now!

 

On the general topic of reverb vs fidelity - I agree that for some instruments it's just not necessary. I've even practiced my cello in a recording room where I used to work - with dappled foam on every surface - and it sounds great, because it's a cello and resonates all on its own. However, I couldn't have played my concertina more than 5 seconds in there without throwing it out the window (actually, it would have bounced off because the window was covered in foam too)!! To me (yes, I know this is the wrong place to say it) the concertina (English style construction) on its own doesn't sound very nice... though with the right acoustic envionment it can sound pretty good. Accordion reeded instruments can sound quite nice even in very dry environments (imo) - like Jody's recording.

 

Greg - your question "why" is very good... Mainly this is just for myself, so I can hear I sound and learn from it, and also I've used it to make a recording of a set of tunes to give to a bouzouki player to get familiar with - the better the sound quality the more chance he'll actually listen to it Finally, the recording gear I have is quite decent so I'm intrigued to see exactly what I can do with it. Oh, and it keeps me out of trouble!

 

Edit: Note that I'm the weirdo who normally plays with wooden baffles on the end of my concertina, so the acoustic sound is slightly different to a plain/vanilla concertina...

Edited September 30, 2006 by RatFace

[Anthony Cipolone]

This might sound crazy, but have you tried recording in your bathroom? Ceramic tiles or a shower give a really live sound without too much bounce-back -- you might not need to do any sort of post-processing at all. Also, if you have a portable system of recording (ie, laptop), try finding a concrete stairwell somewhere. Many students in our Perf. Arts Center rehearse in the stairwells -- the reverb in there is fascinating. I haven't tried it with a concertina, but I've heard everything from voice to trombone to violin in stairwells, and they all sounded amazing. (One student was was putting together a CD liked it so much that they ran a snake from the studio into the stairwell.)

 

If you're going to do artificial reverb, make sure your recording is very dry -- it'll give you more control over the amount of reverb. Adding reverb to something that already has reverb can sound a bit obvious at times.

 

- Anthony

[Jody Kruskal]

This method was used for this attempt at one of Jody Kruskal's tunes recorded a few months ago: Gone Fishing

 

I wonder which church in Chicago was used as the model for the reverb? I grew up there and remember the acoustics of quite a number of churches still.

That's an interesting coincidence. Where in town did you live?

 

Theodore, Danny and All, sorry, I haven't checked this thread for awhile. Nice job with “Gone Fishing” (which is on my Naked Concertina CD and also in my tune book “Feet in the Clouds”)

 

I listened on my laptop speakers only, and from that, I would say that the panning is rather hard. The left being the accompaniment and right melody. So much so, that it almost sounds like two different instruments. Perhaps that would be different on a proper system. Sounds good for all that though.

 

I grew up in Hyde Park. Ever heard the acoustics of Rockefeller Chapel?

www.photovault.com/Link/Cities/ Lake/Chicago/Places/RockefellerMemorialChapel.html

Amazing!

 

As for recording:

 

I liked what Greg said about compromise. My Naked CD was recorded with plenty of it. I needed to do it at home... a hard walled, low ceilinged basement room, a pair of Rode NT large diaphragm mics ($200 each). I live in Brooklyn and on the CD you can hear trucks roaring past from time to time. I put the mics about 2 feet from each end of the concertina and angled them toward me a bit so they were not pointing directly at each other. I did zero editing of the final take for each track, no cut and paste at all.

 

My goal was for the concertina to sound right up in your face with just enough separation to be able to make out the right and left sides and still not have the notes jump back and forth when the melody crossed over. In my room that meant hard panning of left and right.

 

I had it professionally mastered and the engineer used some compression and reverb and an analog tape simulator effect to warm it up a bit, but nothing very drastic.

 

The result? Well... you can hear for yourself if you have the CD. Though my set up was way far from ideal, I think the sound was OK and nobody has complained about the recording quality. All they really hear is the performance. I listen to scratchy old 78s recorded into some cone on wax and enjoy that music too. For a player, I think the performance is the thing to spend your time on if you want to improve the quality of the listeners experience.

 

Still... it is fun to play with technology, though I’m not sure that it counts for too much when making acoustic music once you get up to a certain basic level of recording quality. Sure, if I had used a great room, mics, engineer and all the CD would have been better, but would my listeners have enjoyed it more? Not much, I think.

[Theodore Kloba]

Theodore, Danny and All, sorry, I haven't checked this thread for awhile. Nice job with “Gone Fishing” (which is on my Naked Concertina CD and also in my tune book “Feet in the Clouds”)

Thanks... Of course I have both the CD and the book.

I listened on my laptop speakers only, and from that, I would say that the panning is rather hard. The left being the accompaniment and right melody. So much so, that it almost sounds like two different instruments. Perhaps that would be different on a proper system. Sounds good for all that though.

I intentionally left it somewhat harder than I might otherwise have (maybe too much so, though); I recorded it for other C.net'ers who had never heard a Chemnitzer before and wanted an example of a song they were familiar with. Listening in headphones with that panning gives an idea of what it sounds like to play the instrument. Anyway, I just listened to it again, and I realize how much better I play that tune now. Maybe it's time for an "after photo".

I grew up in Hyde Park. Ever heard the acoustics of Rockefeller Chapel?

I've been in the neighborhood (been in the WHPK studio, which was of course a dungeon by comparison) but never in the chapel.

I liked what Greg said about compromise. My Naked CD was recorded with plenty of it.

Of course, the end result is what matters and I think what you got is just right for the music.

I had it professionally mastered and the engineer used some compression and reverb and an analog tape simulator effect to warm it up a bit, but nothing very drastic.

Your mastering engineer did a great job. Unless your source recording actually sounds "bad", good mastering is transparent like that.