Improving room sound.

[foresense]

I'm used to having a bedroom studio, and because of the extra mess in a room like that it would sound fine mostly. But I've got a dedicated studio room now, and it's sounding a bit hollow.

 

Should I just put up some heavy curtains to a few walls to make it better? What are some easy ways to make a room sound nice? I'm not aiming to do any heavy duty mastering, I just want it to sound good, and not have certain bass notes overly amped.

[LimpyLoo]

The first, basic thing you could/should do is just to dampen any hard surfaces.

 

 

Personally, I just threw up some bed-sheets on the walls (directly behind and in front of my monitors) and it made a huge improvement. My general clutter seems to do the rest.

 

 

I don't have room for bass traps, but the clutter does a good job and I monitor pretty quietly so it seems fine. And I usually HPF my mixes at like 30-40hz anyway so...

[foresense]

cool, yeah I was planning on putting some heavy curtains up first, see how far that goes. I could put a loungy chair in there too. How big are those bass traps? and foam panelling worth it? I see those a lot in studio pics.

[MisterE]

maybe look into bass traps. i don't know anything about that stuff much, but there are prob diy methods for bass traps, which may or may not work super well

and i dont know how much actual bass traps would cost either but maybe something in that field might fall into your budget

bass is prob the main problem you will have imo

[LimpyLoo]

How big are those bass traps? and foam panelling worth it? I see those a lot in studio pics.

 

 

IMO that stuff isn't necessary. It's optimal, but it's definitely not necessary. Bass traps are pretty big if you live in a tiny apartment like I do.

 

From a physics standpoint, as long as you don't monitor extremely loud and your room isn't the size of a closet, you can get away with not having that stuff. If you want to prevent 'standing waves' and avoid having your room be a wash of indescribable low-end, learn the physics of low-frequency sound waves and try to offset the problem with a well-placed pile of clothes or whatever.

 

I mean, if you want your tracks to have perfectly fine-tuned sub-bass, then you might run into problems without bass traps. But like I said my mixes aren't very bass heavy (out of choice) and I tend to just HPF them as I rarely have anything useful below 50hz anyway.

[foresense]

The reverb I have in my room isn't tinny but actually quite airy. The walls aren't concrete or wood, but a softer kind of paneling. I put up some curtains and they dampen things a bit on the high end, and I can hear the difference very clearly in my voice when I talk. But there's still a lot of ring on the low end. Looking into bass traps now, but if there's an alternative I'd like to hear it. Sounds like a costly thing or a big project to make them, and might not be what I need.

[LimpyLoo]

Cut down on as much reflection as possible and see how the bass is then.

[MisterE]

i agree with limpy that if you listen at lower levels you shouldn't have problems, even if sometimes it's nice to be able to blast it loud. itd prob be a good idea to get used to mixing a bit on the quieter side. seems like if you get something sounding good at lower levels it sounds even better louder, imo

[foresense]

I think I can get away with a decent sound level, so I'll see if it starts to interfer. My room went from cathedral to muddy so I'm happy for the moment. I'm interested in clean bass though, it would be nice for once.

[mcbpete]

I say: ask elusive !

 

I actually thought the whole thing was balls, but I watched this video and was surprised that even with Youtube's compression the results are pretty noticeable:

 

 

Though I always do my stuff on headphones, my landlord would never allow me to mod my room in this way, and the difference doesn't really justify the cost for me - so I cannae be bothered with it myself !

[Guest]

+1 what LimpyLoo said.

Bass traps are great but very pricey. Just dampening hard surfaces, even the ceiling, will do wonders.

Positioning your monitors relative to your mix position helps a lot in avoiding bass holes and peaks. Place your monitors and sub where you want them, send a 40 to 80hz pink noise and slowly walk around the room with an SPL meter to find those holes and peaks. If possible, you want your mix position at a distance of the monitors and sub that has a bass response within 3dB of the rest of the frequency spectrum. You might have to move your sub around to get that sweet spot. And it could be in the strangest position - our sub is literally to my far left and we're Dolby Certified.

You can also get IK Multimedia's ARC system to correct your room even more (http://www.ikmultimedia.com/products/arc/). That's what we used for a while in our main mix studio to get a flatter response and it did wonders.

[elusive4]

I'm used to having a bedroom studio, and because of the extra mess in a room like that it would sound fine mostly. But I've got a dedicated studio room now, and it's sounding a bit hollow.

 

Should I just put up some heavy curtains to a few walls to make it better? What are some easy ways to make a room sound nice? I'm not aiming to do any heavy duty mastering, I just want it to sound good, and not have certain bass notes overly amped.

room curtains are thin porous absorbers that will not effectively address any inherent LF/modal issues within the bounded acoustical space. LF issues you experience are primarily a result of standing waves (resonances), that form areas of constructive (anti-node) and destructive (node) interference. these pressure variations correspond to the peaks and nulls within the 2d frequency response, and will cause you to over or under-compensate your mix decisions in that region accordingly. in addition to this type of interference you will also encounter long LF decay times, due to the fact that a resonance is a persistence of energy. perceptually, this will result in the bass notes "running together" without any clear, defined separation at that particular frequency (resonance).

 

the defined resonances of the bounded space are defined by the room dimensions and corresponding wavelengths.

 

as the room becomes smaller and smaller, the LF issues compound (eg, the modal distribution/overlap). concurrently, less overall physical space (real estate) is available that could be utilized to introduce solutions.

 

an additional LF issue is the result of non-resonant interference (speaker boundary interference response), typically in the form of a polar null as a result of superposition between direct signal and an indirect signal with total reflection path corresponding to 1/2 wavelength of a given frequency: inducing 180* out-of-phase destructive interference. an example SBIR phasor would be that incident from the front wall: eg, if the distance from source (subwoofer) to front wall is 2.5ft, total reflection path is 5ft. this 1/2wavelength distance corresponds to 100hz (10ft wavelength), and a resultant polar lobe propagates: (http://i.imgur.com/z0tvrfJ.gif). elimination of the front wall SBIR phasor can be accomplished via soffit mounting the drivers into a high mass, rigid front wall - as is commonly done.

 

the primary tool in the toolbox to address or mitigate modal issues is with respect to the placement of the source (subwoofer) and receiver (listening) positions. for example, placement of the source in a node for a given standing wave will minimize or eliminate the driving of that resonance. due to complex real world behavior, measurements should be utilized to perform this task and identify the "best possible response" source/receiver positions with respect to the LF (modal) region. from here, specific (measured) issues can be isolated and attacked.

 

an additional tool is to apply LF absorption to remove excess energy from the room, lowering LF decay times and minimizing the gain of the reflections to reduce the resultant acoustical interference. this is typically accomplished with pressure-based (helmholtz/perf array) resonant absorbers or velocity-based porous absorbers. the latter is far more common for home/residential spaces as it is an easy solution to construct with little "trial and error" required, but imparts negative constraints such as physical size and depth requirements due to the fact that LF wavelengths are so large. porous absorbers function by converting the kinetic energy of the pressure wave into heat via friction within the porous structure, attenuating the signal. however in order to be effective, they must be placed (or spaced away from rigid boundary) into areas of high particle velocity. pressure maximizes at the rigid boundary (wall surface) while particle velocity goes to zero (inversely proportional). therefore, a thin porous absorber or one placed at the room boundary will not be effective with respect to the lower frequencies (longer wavelengths). the porous structure can be spaced away from the rigid boundary to increase the effectiveness in lower bands, offering a "free lunch" of sorts as a 2" porous absorber with a 2" air-gap will function equivalent to a 4" absorber attached to the boundary (minimizing materials). curtains are not effectively thick as to function as LF absorbers; one must instead construct a porous absorber that is sufficiently large (with respect to wavelength to limit diffraction) and sufficiently thick (as to be spaced into areas of higher particle velocity for the lower/longer wavelengths). based on the available real estate and subsequent thickness of the absorber, a porous absorber calculator can be utilized to identify an ideal gas-flow-resistivity value, and subsequent porous material can be procured.

 

http://soundflow.afmg.eu/index.php/sf-features-en.html

http://www.whealy.com/acoustics/Porous.html

 

as one constructs thicker and thicker porous-only LF absorbers, you will want to utilize a material with lower flow-resistivity (equiv lower density), contrary to the popular misconception that "denser is better". this is due to the impedance jump between air (the medium) and the absorber, as porous absorbers are complex and thus the imaginary component must be taking into consideration as well.

 

there is no reason to purchase any porous-only LF absorbers, as they are relatively easy to construct DIY.

 

You can also get IK Multimedia's ARC system to correct your room even more (http://www.ikmultimedia.com/products/arc/). That's what we used for a while in our main mix studio to get a flatter response and it did wonders.

eq can be useful for issues of non-minimum phase, but elsewhere i wouldn't degrade the direct signal in an attempt to correct for distortion imposed by the bounded space itself.

 

eq cannot modify the polar response of the speaker, the acoustical impedance of the boundaries, nor the time-domain relationships of the indirect arrivals. it has no control over the signal once it has left the source (speaker). the room needs to be modified directly in order to achieve the design requirements.

 

the relentless obsession over "flatness" within the 2d frequency-response is akin to living in Flatland. the frequency response is but one perspective of the acoustical energy in a bounded space; useful for modal region but elsewhere the time-domain takes precedence. time-domain analysis allows one to see the "perspective" of how the indirect arrivals impede the listening position over time. from there, isolated indirect signals can be identified and modifications to the room (eg, an absorber) can be applied to mitigate the signal to work towards the room's design requirements.

[mcbpete]

See - it's as simple as that.

[LimpyLoo]

Elusive, I fucking love hearing you talk about this shit. I get sexually aroused whenever you drop your expertise.

 

 

Where did you learn that shit? Are you extrapolating from a general knowledge of physics or did you study this stuff specifically?

[foresense]

...

 

you should write a book. real nice, thanks.

 

was looking at this:

http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/743040-tims-limp-mass-bass-absorbers.html

and then this:

http://www.irishacoustics.com/index.php/acoustics/diy-acoustic-traps/

 

worth it? or should I focus on measuring my room for better speaker placement?

[elusive4]

inherent issues won't be solved by "placement" alone, but finding the best possible "starting point" is a useful step in the process as the only "cost" is that of your time and effort.

 

room eq wizard (http://www.roomeqwizard.com/) is available free of charge if you have the pertinent measuring equipment (pre-amp, suitable omni-mic, cables, etc). you will want to generate the waterfall/CSD plot of which will clearly detail the freq-response along with LF decay times within modal region.

 

again, porous-only LF absorbers are simple to construct but suffer from size constraints and effectiveness in the lower octaves. construction of a limp membrane absorber is going to require "trial and error".

 

and this only touches on LF aspect, not issues in specular region of which are destructive to intelligibility, localization, and imaging.

[elusive4]

LimpyLoo,

 

this is fairly standard (fundamental) discussion regarding the topic; nothing "extravagant" presented here.

 

authoritative resources would include SSE (http://www.amazon.com/Sound-System-Engineering-Don-Davis/dp/0240808304) and AA&D (http://www.amazon.com/Acoustic-Absorbers-Diffusers-Theory-Application/dp/0415471745/ , http://www.scribd.com/doc/49539019/Acoustic-Absorbers-and-Diffusers) if you're interested further.

[LimpyLoo]

nice, thanks.

[Guest]

I mean, if you want your tracks to have perfectly fine-tuned sub-bass, then you might run into problems without bass traps.

 

 

I'm interested in this; fine-tuning sub bass to fit the rest of my tracks bass content. Lately I've doubling up / layering my kicks with a short blast of 30 Hz sine. My monitor speakers don't go below 50 Hz, but I can definitely hear the sub content through my headphones.

 

While the extra oomph sounds good on my headphones, I'm not sure how the tracks sound on a system with subwoofer, if the short sub clashes with the other bassfrequencies. Right now I'm using the kick/sub track to duck all other tracks through sidechaining, to at least prevent the sub from mixing with the bass-track volume too much. I wonder if it matters much to variate the sub frequencies according to the bassline 'melody', so instead of having a static 30 hz, have it move in the 20 - 50 hz range relatively?