How to improve Rehearsal Room Acoustics?

[Gustavo]

I dont know where to post this, but I figured since I will show off a little bit, then this would be the right place.

I have a rehearsal room I got a few months ago. Pictures can be found here

Yet the acoustics are terrible!! I always record our rehearsals with my Zoom Q3HD, you can find them here (the best one I believe was Moanin, it gets interesting at around minute 4:00)

So far it is a small room, about 6m x 4m and I have two big curtain sets. Before there was a lot of bouncy echo. Now there is no audible echo, but there is a lot of reverb and some weird resonations with certain frequencies.

For the setup:

• Mapex Horizon Drumkit with Zildjian Ride and Paiste Crash and hihat
• Mackie VLZ3 802 that mixes a Bass connected directly to it and my Nord Stage 2
• Behringer B208D, the cheapest compact PA I could find since I did not find the ones I wanted
• Peavey 1970s Tube Amp with EHX Double Muff and EHX Memory Toy

What do you recommend me so that it all sounds less muddy. How can I make a much better recording of rehearsals without breaking the bank?

Saludos,
Gustavo

[gringle]

Hi Gustavo!

Looking at the pictures - the curtains will help to dampen reflections (which is good!) but you've got a very reflective floor and no other damping on the walls.

Ideally (budget permitting) - you'd put in a cheap carpet (deaden floor reflections which will give some artifacts on recording) and add some sort of other damping to the walls.

The cheapest way of doing the floor is usually carpet tiles or a second hand carpet. On the walls, I'd put up curtain tracks and use curtains (thicker the better) over the walls. Alternatively, you could use acoustic foam, but it's not cheap.

I think the wierd resonance is due to where the noise is cancelling out. With curtains over the windows, you've got rid of the most reflective surfaces. However the walls and floor will reflect and then get damped by your own bodies (as it's a small room and there are a few of you in there) - but because you're all standing in different places and possibly moving, it's not going to be a consistent cancellation.

If you can damp the walls/floor as above, then the reduced reflection will mean less sound being damped by people/instruments and make the acoustic more consistent.

Hope this is of some use!

Cheers,
Rob.

[chevere]

Behringer B205D, the cheapest compact PA I could find since I did not find the ones I wanted

Hola hola!
I am sorry but don't know much about room accoustics, but I see you have this Amp, which I consider buying ( I have other thread on headphones but it seems difficult, so getting this Amp could be an alternative (plus a Mic stand to place it 3 foot from my ears during a gig. Would you recommend it or what alternatives did you consider?
Thanks and sorry for getting on this topic!!
ChE

[Frantz]

Thank you Rob, I agree with you.

Gustavo, you may have a look at "Auralex Acoustics Roominators D 36-DST Anthracite".
155 € here.

As Rob suggested, you can think about all the surfaces in your room, each material has reflection and diffraction, the amount depends on the frequency.
From that you can compute the amount of reverberation in your room, here.
In practice, you can trigger a sound and measure the response in your room, it's not easy to do in a nominal (calibrated) way. Just walking around with a microphone and a software like trueRTA, in different places can give you some heuristic.

Hint : if you invite ~ 10 nice girls to the rehearsals, it will also absorb frequencies and reduce reverb

Cheers,
Frantz.

[gringle]

Just to add to Frantz's message above - do be careful, it's a well known fact that only nice girls absorb reverb ...

[FunKey]

If (or as soon as) you are happy with the acoustics while playing, and you just want to improve the recording, here is an idea that won't cost any money. Disclaimer: I've never done this, though I have tried to edit recordings from a rehearsal room and wished I had prepared for that systematically.

First, generate a chirp signal, for example in Audacity ("Generate" menu). For a start, you can try a logarithmic chirp from 50 to 12800 Hz with a duration of 16 seconds; this will give you two seconds per octave and aligns nicely with the equalization tool in Audacity. Play this sound through the speakers in your rehearsal room, e.g. as a sample from your Nord Stage, and record the result just like you would record a song. It should obviously still be a chirp, with as little background noise as possible, but it will have lots of bumps due to room resonances. Load this result into some audio editing software again, and create an EQ curve that turns it back to the original constant-amplitude chirp ("Effect"/"Equalization" in Audacity). (You might have to do multiple EQ passes in series, using large filter lengths for low frequencies and smaller filter lengths for higher frequencies; just always use the smallest length that works.) Be sure to save the EQ curve(s) you use. After you have created one or more EQ curves that neutralize the resonances, just apply these curves to your recorded songs as well.

If you are lucky, everything will sound better, but there is also the possibility that your keyboard will sound better (because it runs through the same speakers) but everything else will sound worse. In any case, you probably need to apply one additional EQ to reduce bass frequencies because your speakers cannot reproduce them as well as higher frequencies, causing you to amplify them too much.

In case you get satisfactory results and want to reuse the EQ curves over multiple rehearsals, make sure the speakers and microphone are always at the same place.

There might be tools to do this sort of thing, but I'm not an expert at all.

[Mr_-G-]

@Funkey: yes, you can do this with a pink noise source, rather than the chirp (so no need to sweep the whole frequency range as the pink noise should have the same energy in all octaves). I think this is what frantzkb suggested with the spectral analyzer. You also need to get a good microphone.
The NS2 has a pink noise sample, but I have not checked whether the spectrum is close to the ideal.
http://en.wikipedia.org/wiki/Pink_noise

[Gustavo]

@Funkey I do not want to get better acoustics for recording but to improve our rehearsals. So the EQ part does not matter much for me, as I am not going to be professionally recording things.

Also, to do the spectrum analysis I was thinking of actually using my Rhode NT1-A and for the noise sources use my laptop where I will be recording everything.with my mackie onyx blackjack interface.

Also, I've been doing some price research and I think these two may be in my budget: http://www.sweetwater.com/store/detail/Project2Kit http://www.sweetwater.com/store/detail/RoomDSTAlBur/ I just need to verify shipping and import taxes to make sure I can afford them.

Also, I was looking at a table of sound absorption and it convinved me to get a carpet floor and to maybe even add some 2' fiber glass or a some high density polymere like auralex has.

I will keep on thinking about it. And see how much money I'm willing to spend and if my bandmates are willing to invest too.

[Gustavo]

Behringer B205D, the cheapest compact PA I could find since I did not find the ones I wanted

Hola hola!
I am sorry but don't know much about room accoustics, but I see you have this Amp, which I consider buying ( I have other thread on headphones but it seems difficult, so getting this Amp could be an alternative (plus a Mic stand to place it 3 foot from my ears during a gig. Would you recommend it or what alternatives did you consider?
Thanks and sorry for getting on this topic!!
ChE

THe Behringer B208D are ok for Organs, EPs and synths. But for Acoustic Pianos, they are truly lacking. Still, if its only for monitoring I think they could do a good job since they are compact and cheap.

EDIT:: I just realized that I mistyped 205 instead of 208, I got the 8 inch monitors!!

[cphollis]

Late to this thread, but I've conquered this problem in my own way ...

It's all about soaking up reflected acoustic energy in my book. If it's a hard surface, the sound will bounce -- period. The less, the better.

When I re-did my basement a few years ago, here's what I did:

- acoustic tile hung from the ceiling
- thick, lush carpet with foam padding
- power outlets everywhere, bathroom, couches, and a keg-erator (really!) -- ok, not about the acoustics, but ...
- thick curtains on every window
- multiple hanging wall panels, built by stretching fabric over large frames with pillow filler behind it (fabric store!)

Needless to say, my wife was very helpful and supportive ...

The room now soaks up sound like a freaking acoustic sponge. You hear the instruments, not their reflections. And you can play quite loud if you want, but it doesn't sound harsh.

The problem now is that we sound very different on-stage, without all those great acoustics

Maybe more than you had in mind, but I nailed it