Recording double bass - suggestions sought

[jakenewmanbass]

[quote name='51m0n' timestamp='1322732265' post='1454917']

Treating that room a little with some basstrapping, broadband absorption and diffusion would make it sound great for tracking though. Not that its awful right now, just 'there' quite a bit.
[/quote]

I'd love to hear you expand on that info Si, I agree it's not too bad but I really have to think about not reducing the space any more so I'm thinking of softening the corners between wall and ceiling and putting absorbent materials behind fixtures like the drum kit and desk.
I am also going to make some sausages... Lol seriously, I did some sessions at the dairy in Brixton and they had muslin wrapped rockwool in long (about chest height) flat ended sausage shapes half a dozen of them made a very effective booth.

Edited December 1, 2011 by jakesbass

[51m0n]

Ha ha, that puts the compressor talk to shame, and I am no expert on acoustics, I've just read a fair bit about it, and tried some variations on the theme.

I'll attempt a brief synopsis though:-

Sound reflects off a surface much like light does off a mirror, different surfaces reflect different wavelengths of sound, and absorb others ( a bit like colours then). IN very very simple terms hard surfaces reflect high frequencies (and low frequencies), soft surfaces absorb high frequencies (but not low frequencies).

The brain takes this reflected sound information and turns it into a very accurate model of the space in which the initial sound occured, where the sound is relative to us, the size of the space, the material bounding the space the number of boundaries to the space, the distaince of the source from the boundaires of the space etc etc.

Standing waves in a room occur where the wavelength of a frequency matches the length of one of the rooms dimensions. The result is large peaks and nulls at that frequency as you move around in the room as the reflections from walls add or cancel each other - not good.

The very worst type of room is a cube, but parallel walls are generally not good as they tend to create strong nodes (peaks & nulls). A parallel ceiling and floor is a source for standing waves too, unfortunately.

Any kind of eqing for a room is doomed to fail as the room is the issue, it cant actually work anywhere but in the tiniest area of the room and should be disguarded as a solution to a difficult room, especially a room in which you intend to do any tracking at all.

Absorption is where you try and turn acoustic energy into something else, heat usually, by impeding the acoustic wave in some way.

Diffusion is where you take a reflection and scatter it so as to make the resultant reflections no longer appear to be from a single point.

Bass trapping is absorption aimed at the lowest (and most difficult to control) frequencies and uses some ver special tools.

So what does all this mean?

You need to fool the brain into thinking the space you have is bigger than it is.

To do this you need to create some broadband absorption to deal with that nasty slap back delay (the metallic ring you get if you stand in an empoty room and clap your hands).

There are hundreds of examples of making a simple absorber on the web, you need some Rockwool RW45 or RW60, a good 4" to 6" thick and as big as you can (say 4' by 2' minimum), enough 2"x2" to make a frame, some cheap material you can blow through, and some nice material you can blow through. Make you frame and staple the cheap material to it. Put you nice material on the deck, put the RW on top, put the frame on top of that, cheap material against the RW. Pull the nice material up and staple it to the back of the frame all the way round, with a little compression of the RW and some careful folding you can get a nice looking result with no creases. Note the frame attaches to the wall and the RW is held off the wall by the thickness of the frame you made, this is important as absorbers like this work by slowing the movement of the air molecules, and if they are hard against the wall then they dotn work as well. Ideally they should be 4" to 6" off the wall.

A simple rule of thumb, a third of your wall area can be covered in absorption like this. Staggering the absorption works well (so absorption mirrors wall. Then hang some off the ceiling (again maybe a third of the ceiling area covered) especially if your ceiling is less than 15ft tall.

As a rule of thumb in a small room (ceiling less than 10ft, length less than 20ft, widht less than 15ft) you simply cannot have too much bass trapping.

Bass is really hard to deal with, the deeper the bass the more difficult it is. The nature of acoustics mean that the corners where walls meet give you double the bass trapping effectiveness, and where the floor and walls meet you get another doubling.

So corners are where you want your basstraos to be, a very simple and effective way to bass trap is to make a superchunk, whereby you cut triangles of RW45 and fill (literally) the corner of the room from floor to ceiling with RW, then put a frame up and stretch nice material over it to hide the truth. This works and is simple but requires a large amount of RW. ANother approach os to build two absorbers like the ones above, one 6" deep and one 4" deep and put them in the corner as follows:-

[url="http://forum.studiotips.com/download/file.php?id=5184"]http://forum.studiot...ile.php?id=5184[/url]

The trick here is to use less dense material for the filler (so nothing more than RW45, something equivalent to an RW30 would be fine).

These are really effective for less material.

Even thenther are cases wher you cant really get to grips with the lowest of the low, and at this point you need to investigate membrane absorption if you want to get really good results.

Check out the BBC R&D pages there is a whitepaper in there that detials the building of a modular membrane absorber that takes out frequencies around 50 to 100Hz, and its basically a box made of ply, with a front of very thin ply filled with pink fluffy roof insulation. The dimensions of the box are super important as is its airtightness, but basically the low frequencies are spent trying to flex that ply membrane, and the result is a very thin (~6" deep) extremely effective bass trap. More time consuming than the other methods, but taking up less space in the room.

Finally with all this absorption going on you are in danger of making the room lose a lot of top end, diffusion is one way to help move the top and around the room more evenly. It is a big topic though, there are various mathematically derived systems (2d, 1d, slats, etc etc) for diffusing the sound, its seriosly complex but putting a diffuser up imbetween each absorber can really help stopping a room get too dark sounding. Have a search oin gearslutz in [url="http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/"]the acoustic forum[/url] some more detailed info.

A good point to note is all this stuff needn't be guess work, for a small outlay you can get a measurement mic (£30 for a perfectly reasonable Behringer one) and using some free software you can measure what is happening in your room with regard to early reflections a frequency/decay time waterfall plots and really scientifically improve the space. In the meantime get some bass traps in there and some absorption on the walls!

Edited December 1, 2011 by 51m0n

[jakenewmanbass]

Some very interesting points there Si thanks for that. As it happens I've done a DB session in there today and had an engineer come in with some nice mics and a portable pro tools set up. The chap that came in was Steve Ancliffe from http://www.bigbluemusic.biz/Site/Welcome.html

I asked for his views on this too and he was saying similar stuff to you he did say that the liveliness was something that I should keep available as an option so suggested having moveable stuff.

I should have mentioned that the floor and ceiling are not parallel and that the end wall is not perpendicular to the side walls which means that waves are being sent in different directions already. Steve said the wooden floor was really helping so I'm considering getting a large absorptive cloth (like a black out cloth) for one wall, I kind of did that today with a mattress and some blankets and it cut the reflection dramatically.

[Bilbo]

The bass is a lot more in tthe foreground than mine and is much more like what I am trying to get. And the playing is great. The only thing I don't like is that ringing sound that underpins everything. Sounds like something ringing in sympathy to the lower frequencies (it reduces as you go up the neck)?

[jakenewmanbass]

Yep I think that's the 'room sound' Si and I are discussing, as you can see above I'm looking into ways at manipulating that but as Steve (see earlier post) mentioned today there will be times where that effect is an asset...

Edited December 2, 2011 by jakesbass

[Bilbo]

Wow. Never realised that the room could have that kind of effect. May explain some of my earlier frustrations (that I have not posted here )

[Bilbo]

Just listened to my efforts again, Jake, and they have EXACTLY the same ring in there!!! Well, I'll be.... I learned something valuable today!

[jakenewmanbass]

It's a fascinating process... it also adds weight to the old pro idea of playing to a room. If you listen to some live albums by really great players you can hear them adjusting what they do to their environment, Rob I know you have 'James Taylor live', check out the way Jimmy and Carlos Vega play the grooves right back and keep dynamics under control... a masterclass in 'doing it right' this relates to what we are talking about here because the first thing you should be able to control as a player in a given environment is your playing. I know that some of the producers I have worked with like me on upright because I can keep things under control and be tidy and quiet (apart from my rather heavy breathing ) sounds like an old man shagging sometimes

[jakenewmanbass]

As soon as I have the results from today sent over I'll put some excerpts on soundcoud (well, when it's released, it was an album session)

[ironside1966]

Recording everything dry is quit a modern approach, a lot of the old and great recordings both rock and Jazz where recorded in colored rooms, it is not about recording an instrument it was about recording an instrument in a room and a engineer would put has much emphasis on placing the instrument in the room has he would about microphone placement.

Edited December 2, 2011 by ironside1966

[ironside1966]

With acoustic treatment there is a balance between what is needed and what the wife will put up with. One option is, instead of trying to dampen the room use reflection filters to stop the reflections getting into the microphones. it might be worth trying to placing the double bass on a large acoustic foam tail. Try playing facing a bookcases with a quilt hanging behind you.
The problem with double basses it is a large instrument and the sound comes from all the instrument not a small part and the low frequencies hare hard to control in a domestic environment.
If you understand how and where a instrument producers sound then you half way there to getting a good recording but it's also impotent to understand the sound you are after then you can look at the best way to record it. do you want a in your face close up sound, natural sound or a recording made on a old jazz club A couple of things I have done in the past that might help you is, to use a matching EQ with an imprint from the type of sound you where after and a and convolution reverb with a small jazz club type impulse response.

[Bilbo]

There are lots of technological developments in recording that have some bearing on all of this. The early stuff was recorded through horns and drums were not used because they made the needle on the recording equipment jump. As things like rudimentary multi tracking came on line, the first studios had 2,4, 8 and 16 track studios and I suspect it was a long time before bass players got a look in in terms of having their own track allocated. So a lot of older recordings will not have 3 tracks dedicated to the bass (say a di, a close mic and a room mic). So classic jazz would inevitable sound very different to what we hear today. I have listened to loads of Paul Chambers who was probably one of the most recorded players between 1958 - 1963 and his recorded sound varies massively depending on where the recording took place and how much time was available to record and to mess around getting a sound. He used a pick up close to the end but, by then, he was recording a lot less. I guess this all has an impact on what we hear as a generic jazz double bass sound. In the 70s, it wsas low actions pick ups and close miking and some of the sounds are really clanky.

[ironside1966]

Some of the old recordings were made using ribbon microphones. Ribbon mics has a subdued top end unlike modern budget condensers that can be quite brittle. They also have a figure 8 pattern and react to transients differently giving a subtle compression effect. I am not saying go out and bye a ribbon mic but understanding how the recordings you like were made and the equipment used go along way to getting the sound you want.
The Internet is full of people arguing about the best technique, preamp or microphone to use but they often fail to ask the most basic question, what sound do you have to start with and what sound you want to record, a multi- mic and DI set up is not the best way to get the old 60s jazz sound if that’s what you are after. The sound of the room is not away your enemy and sometimes the strangest positions can yield good results.
It is so easy to think that a getting a great recording is only the next purchase away. IMHO If you can’t get a good recording with a reasonable quality large diaphragm condenser and even the some of the cheapest models are capable of good results then it is down to user error or poor room acoustics. I am sure with a little time and trial and error there is a recording you are happy with in your house.

[Bilbo]

Absolutely - and a lot of fun and learning in the trying.

Personally, I will be happy if the recording sounds like the bass does rather than like the bass does at the far end of a really long corridor!! !

[51m0n]

Jake asked what I meant by getting the room up to shape for tracking. You can still have massive control over the liveness/openness of the room, if you need a little more top end some brown paper imbetween the outer layer of nice cloth and the RW45 in the multiband absorption will bring back a lot of top end. Also you can simply cover some of the absorbers up with a sheet of ply if you want to make the room more live.

Its about controlling the room in order to get the best recording, rather than having the room control your recording.

At the other end of this spectrum is building a few gobos - 5 'x 4' x 3" frame, on good sized T-bar legs, double layer of (different thickness) gypsum on one side, fill the frame with rw45 and the nice breathable material over that - can be made to look really pro with some thought, and will hugely cut down reflections. you wouldnt need more than three, the gypsum side will provide a tight live feel (go to town and put a diffuser on that side if you like), the other side will absorb a lot. Wont sort out the bass like real trapping but if you arrange about three around the bass then you will really get a start on improving the sound.

You can get superb ribbon mics for pants all money these days, invest in a Cascade Fathead II with a Lundahl transformer mod and you are golden, about £150 IIRC. Great mics, and absolutely awesoome on guitar, and vocal (esp dark sounding classic jazz vocals). They really do react very differently to a condensor, controlling the transients (they dont react fast enough to really bring the transients out, so are absolutely fantastic on very bright percussion signals too). Great mics, very very different from.

Above all experiment with controling the room (duvets and heavy carpet gobos will do for now), and the mic position. It makes all the difference in the world Bilbo!

[Rimskidog]

[quote name='ironside1966' timestamp='1322852596' post='1456756']
Recording everything dry is quit a modern approach, a lot of the old and great recordings both rock and Jazz where recorded in colored rooms, it is not about recording an instrument it was about recording an instrument in a room and a engineer would put has much emphasis on placing the instrument in the room has he would about microphone placement.
[/quote]

Spot on. And in the best studios this still happens!

[51m0n]

Unfortunately for Bilbo his music area is not a studio, well, it is in that he records in it (as good a definition as any), but it would not enter into your top ten list of studios to visit before you die I think
(your gaff is very high up on my list, just below Manifold and Bridge if I'm completely honest )

Which is his problem and why I really think a little work on the acoustic space and the mic position will pay more dividends than anything else in enabling him to capture a more direct source heavy sound.

After all if the source sound isnt working no amount of kit will get it there (You can't polish a turd etc etc), and as the source in this case is heavily room influenced he needs to fix the room (at least from the mics perspective).

Edited December 4, 2011 by 51m0n

[Bilbo]

Crect..... I nhaven't been in a proper recording studio for years. I think it was pre-millenium? I am trying to get a good sound in my music room which is a sort of loft space, an ordinary bedroom with a sloping roof. You can see it here, particularly on the headstock shot.:

[url="http://basschat.co.uk/topic/93958-i-did-it-now-with-photos/page__hl__gedo+musik__fromsearch__1"]http://basschat.co.uk/topic/93958-i-did-it-now-with-photos/page__hl__gedo+musik__fromsearch__1[/url]

[ironside1966]

Before you invest in acoustic treatment you should understand why you need it and what you need. If I were you Bilbo I would Spend a couple of days playing the bass wearing headphones with someone moving the microphone about, try various rooms, positions in the room and mic positions. even if you can't get the sound you want you will have a better Idea of what's wrong. Next step is to see if you can improve the acoustics with what you already have in your house. When I started playing and by first PA's all I my gear was crap although this was frustrating at times the lessons I learnt were invaluable.

Some engineers rely too much on presets, if they want to EQ a bass drum it is easy just to use a preset. It is not unusual for engineers to take this approach to mic placement, every time they record an instrument they use the same method. the trick is when you mic up an instrument is to find the sweet spot or the sound closest to what you want.

If you like the sound of you bass then why not place the microphone near you ears, it is worth noting that the sound a player hears is different to the sound in front of the bass. From what I see from your photos you have a wooden floor that might be part of the problem.

[51m0n]

Agreed, see how far you can go with anything you can find to get a better recording, then if you want look into making something abit more full on (decent gobos for instance) and then if you really want to go the extra mile look into a more complete acoustic solution.

By the way, and this is for Jake since he was asking, here's a link to some info on building diffusers based upon the BBC paper from 1990, [url="http://www.pmerecords.com/Diffusor.cfm"]LINK[/url] & [url="http://www.bbc.co.uk/rd/pubs/reports/1990-15.pdf"]BBC Whitepaper LINK[/url]

Hope thats not to scary (it amounts to cutting up some 2x2 and glueing it on to a board!)

[jakenewmanbass]

Only just revisited this thread, cheers Si.