Just Two Broadband Panels
I’m amazingly lucky in so many ways, and one of them is my good fortune in having a dedicated recording space. I can leave mics and guitars out, decorate to my preference, put speakers in the middle of the room, and best of all, hang broadband absorbers all over the walls and ceiling and stuff them into every corner.
I found that installing these panels made a lot more difference in the quality of my recordings than upgrading a preamp or a/d converter, or even buying a new microphone. By improving the sound in the room, the acoustic treatment made the whole recording process much easier and more enjoyable. So when people ask me how to improve their recordings, one of the first things I suggest is room treatment.
Minimum Impact, Maximum Result
Unfortunately many people don’t have a dedicated recording space. They can’t stuff a dozen panels into corners or lean them against walls, and they often ask how few panels they can use and gain any benefit. My standard answer is two, just two panels can reduce reflection in one small area, an area just right for recording acoustic guitar or vocal or many other acoustic sources.
There are a number of commercial products born out of this idea of a zone of controlled reflections. Some of these are rather small and thin, so I’m doubtful that they’re strongly effective. Some are fitted with frames and/or attachment hardware. This adds flexibility and a pro look, but also adds weight and cost. My preference is a pair of simple unframed panels, 2 feet by 4 feet by 4 inches of OC703 compressed fiberglass. I made mine with burlap and hot glue, but premade panels are available as well. Here’s the blog entry on building these panels: Building a broadband absorber (on the cheap)
I deploy the panels in a V surrounding the microphone(s), often by simply leaning them against the mic stand if it’s sturdy enough. If needed I lock the panels in place using a bent coathanger poked into the fiberglass to add a little stability. I’ve experimented with different positions for the panels and this arrangement has seemed the most effective to me. The sound leaving the guitar, or at least a lot of it, passes through the panels as it leaves, so it hits the microphone full strength, then gets attenuated by the panel. Then after the sound hits the wall it returns through the panels for further reduction before hitting the back and sides of the mics.
Let’s Listen
In order to evaluate this two panel approach I set up in our guest bedroom, a 12 x 14 x 8 foot space with no room treatment and only a futon for furniture. This is a fairly reflective room and seemed like a good place to test the two panel solution. I used the Zoom Q3HD as the “mic” and placed it about 24″ from the guitar, with the stick-on wide angle lens attached Zoom Q3HD with a Stick-on Wide Angle Lens then I setup the Xacti HD2000 for a wider shot.
Here’s the resulting video:
Conclusion
I hope you’ll listen and make your own judgment, but my opinion is that the two panels do a remarkable job of cleaning up the early reflections and reducing the “small room” sound. The direct to reflected ratio is improved with a couple of benefits. Since the reflected sound includes a lot of high mids, the sound with the panels is “warmer” with those reflections reduced. The other effect is to make the recording sound like it was made with a closer mic position or in a much larger room.
I’m pleasantly surprised by the effectiveness of this two panel approach. They’re small enough to be stored under a bed or behind a door, they’re light enough that they can be moved into position quickly and easily, and even purchased commercially the cost is under $200. It’s possible that one or two more panels might improve things further, but in my preliminary comparisons it seemed that the big improvement came from two panels, and one or two more panels did not provide much additional benefit. Your situation could certainly be different, of course.
This entry was posted on Sunday, December 11th, 2011 at 9:54 am and is filed under Acoustics, Recording, Tutorials. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
catherine cunningham said in post # 1,
on January 14th, 2012 at 8:45 am
I hear lots of difference (a rarity in these tests) and I prefer the sound with no panels – maybe that’s why i’m always arguing with the sound engineer!
David Rose said in post # 2,
on March 11th, 2012 at 7:13 pm
I really enjoyed the panel demostration. I look forward to seeing more of your videos and reviews. I hope to hear from you and thanks so much.
davidrose1962@comcast.net
Eugene Sukhorukov said in post # 3,
on March 17th, 2012 at 3:50 pm
Thanks a lot for these videos! I am looking all over the internet for any useful info on how to do a decent home recording. Your demos and tests help a lot. Looking forward to more of those!
Eugene
Peter Keane said in post # 4,
on May 11th, 2012 at 12:50 pm
Very helpful indeed! I find the versions w/ panels much more focused & uncolored. I assume they’ll be much more amenable to further processing (if necessary) in the mixing process than the version w/ no panels.
Fran Guidry said in post # 5,
on May 11th, 2012 at 1:44 pm
Peter, you’re exactly right about the aim of using the panels. Reflections currently cannot be processed out of a recording, so any post processing has to work around them.
Fran
Carolyn Stephens said in post # 6,
on April 3rd, 2013 at 4:07 pm
This video comes at just the right time. I’m trying to record a solo guitar in my little studio (small back bedroom) and the reflections are out of hand. Thanks for your thoughtful and economical solution. Can’t wait to try it.
Fran Guidry said in post # 7,
on April 3rd, 2013 at 6:14 pm
I’m glad to hear this might be useful to you. Please let me know your results.
Fran
Carolyn Stephens said in post # 8,
on April 4th, 2013 at 8:08 pm
I have a pretty small recording space, and could really use only two panels (no room for more than that). Have you ever thought of selling these things for those of us that don’t want to buy all of the fiberglass panels that we wouldn’t/couldn’t use? I’d be willing to buy two panels from you, and probably someone else is in my same boat. Just a thought. You could take pre-orders to make sure it was worth your time.
Fran Guidry said in post # 9,
on April 4th, 2013 at 9:42 pm
Carolyn, thanks for the suggestion, but I’m retired and happy spending my time playing with video cameras and guitars.
There are a number of companies that make panels like these. The guys that I got all my info from, RealTraps http://www.realtraps.com/products.htm is one. GIK is another http://gikacoustics.com/ I’m pretty sure there are other vendors out there as well.
Fran
Clive said in post # 10,
on November 17th, 2013 at 10:24 pm
Fran, it’s really good of you to put up these essential demonstrations of gear and techniques – can also appreciate how much effort goes into getting it right.
Your playing also is a real pleasure, not to mention your evident enjoyment.
Now my first impression with these gobos is a little like the gentleman who wasn’t sure whether he didn’t like the untreated version better — though the quick a-bs at the end might change that.
I am also thinking of the absolute intensity I had once doing a 3.5 hour voiceover (in many sessions) in and out of studios for a multimedia event from Switzerland…and maybe that helps understand what else may be going on here.
First, I think you’re spot on in thinking about off-axis frequency response. One of my largest problems in that voice-over situation was a very hot, narrow frequency response off the back sides of a variable-pattern large condenser mike which sounded in other regards very good on that setting. This hot angle pitched up the room reflection as a narrow-band slap echo, very unpleasant, until realized and remedied by going to a more conventional pattern. Gobos were not enough, that I could have anyway.
Now, what I may be hearing in your recordings here. Notice what happens when you back away on the un-goboed first cut, after carefully enunciating your set phrases. Sounds different in your relaxed position, doesn’t it. Also, notice what happens with your Xacti? video mike sound when you talk past the gobos before switching to the Zoom mike and camera…
Then, the first recording without gobos does have room reflection etc. big time. Yet, in some regards the sound seems rather natural, if not at studio neutrality.
With the gobo set, now you have the main room reflections out — but not all. This changes the balances, and I believe shows that the guitar vs. microphone placement is actually too close for the primary sound. Guitars, as you surely know are very hard to record well, and especially with a single microphone, and so long as you didn’t have the reflections, more distance would help, can help in this case I am suspecting. Said as a player again, not as a recording engineer!
So without guessing more, I am thinking that the best of all your arrangements would be with the gobos, but both your voice and your guitar at a larger distance in the case where you have them. Then I think the best naturalness would occur — with the caveat that from hearing sound change as you do move around, particularly the voice will be best only at some critical distances.
This is because room reflections remain, from directions you couldn’t attentuate, which is natural.
More answers (and questions) are present in the realtraps video/audio demonstrations. Having had some experience in real broadcast and recording studio situations, I’m thinking that the real answers lie in areas neither they nor you want to go to — in the recording room, and in the microphones.
The serious studios really seem to me to have had dead rooms, much more so than either home studios or a treated living room can achieve, even where a tolerant partner is involved as in their filmes. There is a very slight and broadband neutral reflection to those rooms that are not huge – so that your own voice sounds back to you as if it is already on a Neumann of some expense. But then the rest of any reverberation is put in under control and with the neutral precision of effects, which can be these days anything you choose, even replications of ‘good’ spaces that exist in the world, such as concert halls or as I have found once in a while, a ‘nook’ for example in a complicated house’s living room which just sounds very good for conversation — accusing the architect there, or he just got lucky; we will never know.
The other point is those expensive, and mysteriously effective microphones, because I think some of them at their expense really observably work. Probably the reason is very, very uniform frequency response in all micro-directions and distances, while that seems to be a tough thing to do, particularly combined with some of the more interesting non-flat responses some very favored microphones can have. And thus as observed also, they work well individually to individual voices, or instruments, or situations….
Your recordings and your own comments have helped my memories piece something together here, so thank you again, Fran. It’s very fine to do the things you love in later life – something I work with here as well.
Best fortune,
Clive
Fran Guidry said in post # 11,
on November 20th, 2013 at 7:50 pm
Hey, Clive, thanks so much for stopping by and commenting so extensively.
I’m certainly not proposing that two panels will get us results similar to a fully and professionally treated space. Physics keeps getting in the way of miracles like that. I was aiming my information more at those seeking maximum impact for minimum cost.
I’ve found that to the non-professional listener the qualities of the most expensive, and presumably finest, microphones may well go unappreciated. It seems that those with plenty of experience develop a taste for the subtleties of the finest mics, but I’m not convinced that those subtleties are required to capture and convey whatever emotional impact was present in the performance.
I look forward to your future observations, thanks.
Fran
robert said in post # 12,
on June 5th, 2014 at 4:44 am
RE: broadband panels. I use 24sqin mold resistant sound absorbing ceiling tiles, mounted with plastic pipe brackets on microphone boom stands, with boom set in a cross arrangement. I place one behind the vocal recording mic. and the other in front of closest wall within microphones pattern that may cause early reflections. Seems to be a a decent setup.
re: website. You could make website much more mobile-friendly simply by making the next and previous page gadgets much larger.
Thanks for the great source .
Fran Guidry said in post # 13,
on June 5th, 2014 at 8:56 am
Thanks for the advice on a mobile friendly site. I need to choose a new template and revamp things but I’ve been lazy.
Fran