Reflection Filters & Less Than Ideal Recording Conditions

[FFTT]

Working in an untreated room where background noise and room reflections can cause all kinds of hassles when micing a vocal, you have to get creative.
One answer was building a moving blanket tent over boom stands, behind the mic and behind the vocalist.

Another way is to use highly directional, dynamic or condenser mic's with strong off axis rejection.

You can also use a noise gate, software or hardware.

A friend just turned me onto the new selection of reflection filters designed specifically for reducing those
room reflections and background racket.

Here's two different versions, I'm debating between if I can find the spare funds.

If you like me are dealing with background noise and room reflections, something like these is certainly more convenient than building blanket forts.

There are several different ones available from around $80.00-$249.00
Some with, some without stands or booms.

SE Reflection Filter Pro $249.00

SM Pro Audio Mic Thing 2 Portable Microphone Isolator $199.00
This one includes a stand for the price.

 

[silky smoove]

You'll find people's opinions of these devices varying wildly. I've never used one as my space is fully treated and wouldn't benefit, but I did some research when I first heard about them a couple years ago. It seemed to be a 50/50 split of people that swear by them, and people that despise them. Lots of claims on both sides of the argument. I suppose you could try one for yourself and see if you like it, then return it if you don't.

The SE model in particular is relatively expensive for what it is. It's not really going to provide much in the way of isolation, despite their claims, but it will potentially clear up room resonance right at the mic capsule. You could always do the "hang a mover's blanket BEHIND the singer" and get a comparable result. People have been doing that for decades, and it will only cost you about $10 for the blanket.

 

[Dima B]

I think these devices are useless in this case, especially for male voices. The most important problem is the low frequencies, how "low" depends of the room configuration. Thin layer of foam can't resolve this problem. It is just ordinary physics and nobody can cheat ordinary physics but can cheat ordinary customer They can absorb and reject some high frequencies so sound with and without is different but it is inappropriate for commercial grade recording anyway. But it is useful in good professional neutral rooms which always have a bit of "live" for musician comfort and it can kill part of it.

 

[silky smoove]

To be fair, there's a deconstruction video of the SE model. There are several different types of material in it. They're arranged in a fairly logical way. I'm still not buying one, but it's definitely more than just some Auralex strapped to a curved backing frame.

 

[seamonkey]

Directional mics are designed in a way that sound entering the back and sides is canceled in the mic capsule.
Blocking the back can make them worst.

Mics have been designed for decades with little change on how the pick up sound. If these shrouds really made a difference I'd be totally surprised that mic makers missed this all these years.

There might be some poor mics that someone got better response out of, I doubt any quality mic would benefit.

I've actually never heard a simple sound clip of before and after one of these.

 

[Dima B]

Good video and right conclusions. It can't replace a good studio room but can make your records a bit cleaner in some cases. And dirtier also, I suppose, if you place it before three-four foots absorption wall layer in a studio that works better anyway. Because of "Science running everything since 1543"

 

[silky smoove]

I'm still in the camp of using a mover's blanket BEHIND the vocalist to achieve the same result for far less money, and without blocking the backside of the mic, assuming you have a crappy room. Mine is far from crappy, so I won't be bothering with either

 

[Dima B]

I've actually never heard a simple sound clip of before and after one of these.

Even in this video that clearly says to us that this guys have precision instruments for testing they don't do it or share results. It starts as "commercial" and ends as "professional", this guys obviously didn't want to injure SE but they professional ethic is strong enough for telling the truth.

 

[testing1two]

This is a very informative article on reflection filters and how they affect the sound of the source (for better or worse): How Effective Are Portable Vocal Booths?

I actually use the Kaotica Eyeball simply because the form factor is so much easier to work with.

 

[silky smoove]

Per the article, it's filtering out upper mids and highs, and increasing resonance in the lower midrange. That's exactly the opposite of what I would want on a vocal mic.

 

[FFTT]

This is good input to ponder, thanks!
I could get a real nice boom stand and moving blanket or just use a comforter, for sure.
I've got air handler issues, especially during cold weather, plus an open archway to the kitchen.

I'm getting better than expected results considering my conditions, but there's always room for improvement.
Formal proper room treatment is not an option.

I'm in my largest convenient room so I can run my various amps at ideal volumes.

Vocals and acoustic guitar are more difficult to get good and clean.

 

[testing1two]

Per the article, it's filtering out upper mids and highs, and increasing resonance in the lower midrange. That's exactly the opposite of what I would want on a vocal mic.

In theory I would agree with you but I think it's important not to get too caught up in theoretical ideals without doing some actual listening tests. After all, 90% of the acoustic treatment people put in their rooms does the same thing as a reflection filter: absorbing high to mid frequencies and allowing low frequencies and low-mids to bounce around with impunity right back into the mic. If a reflection filter delivers comparable results without hanging foam on the wall or constructing an elaborate "packing blanket fortress" around the mic, then it makes pragmatic sense to me.

That said, if you don't mind the price tag, the Kaotica Eyeball specs are very good and I certainly enjoy mine: [Invalid or Expired Link Removed]

 

[silky smoove]

I don't agree with that sentiment. People doing an incorrect version of sound treatment doesn't justify this incorrect version of sound treatment. I know you weren't saying that explicitly.

There's no shortcut in time, money, or effort when it comes to sound treatment. It's a complicated, involved, and typically expensive (even DIY options), so people try to cheat it. You can't cheat physics.

 

[kenneffdupriest]

we made a vocal booth out of office cubicles. It works great, cost very little and can be used for other instruments also.

 

[silky smoove]

Run an RTA on your office cube booth. My suspicion is that it's killing reflections at the expense of mids and highs. That reduction of midrange and top end detail might be preferable to the reflections outside the booth, but it wouldn't be ideal. Just a suspicion, but given the results of most DIY solutions involving unintended materials, I'd bet I'm right.

 

[Dima B]

After all, 90% of the acoustic treatment people put in their rooms does the same thing as a reflection filter: absorbing high to mid frequencies and allowing low frequencies and low-mids to bounce around with impunity right back into the mic.

Exactly! There is why these rooms are not work well

If a reflection filter delivers comparable results without hanging foam on the wall or constructing an elaborate "packing blanket fortress" around the mic

It does not. Because you have to use at least quarter of wave length absorption layer for its reduction. Some composite layers and right placement can decrease this thickness but not dramatically. Even very special and complicated systems for the narrow low frequencies range reduction which are used for a precision correction in famous studios are huge usually. So if you use couple of inches of the ideal absorption material you can reduce frequencies from 1700Hz and above only. Male voices can utilize frequencies from 49 Hz (academic low basses), "standard" for contemporary music baritone starts from 110 Hz so you have to use around 3 foots (~0,78 metric meters actually, I am from "metric" country and do math in it) of absorption material for making it perfectly clean at least. Nothing personal, just physics and math All another options are marketing ******** (pardon).

 

[testing1two]

I don't agree with that sentiment. People doing an incorrect version of sound treatment doesn't justify this incorrect version of sound treatment. I know you weren't saying that explicitly.

There's no shortcut in time, money, or effort when it comes to sound treatment. It's a complicated, involved, and typically expensive (even DIY options), so people try to cheat it. You can't cheat physics.

I agree you can't cheat physics. I agree that comprehensive acoustic treatment is not only expensive but impossible for most home studios.

But that said, in many cases, you don't have to cheat physics to get good results. Some top engineers and producers (like Allen Sides, Jeff Lynn and Glenn Ballard) have recorded hit vocals and entire hit records in living rooms, bathrooms, and other unlikely spaces with little more treatment than a few packing blankets and rugs.

My point is simply this: don't let lofty mathematical dreams of acoustic perfection discourage you from experimenting and making music. Sure it's easier to get great results if you have great gear in a perfect space but people are making great recordings every day in not-so-great spaces...and I bet some of them are using reflection filters. ;-)

 

[testing1two]

Exactly! There is why these rooms are not work well


It does not. Because you have to use at least quarter of wave length absorption layer for its reduction. Some composite layers and right placement can decrease this thickness but not dramatically. Even very special and complicated systems for the narrow low frequencies range reduction which are used for a precision correction in famous studios are huge usually. So if you use couple of inches of the ideal absorption material you can reduce frequencies from 1700Hz and above only. Male voices can utilize frequencies from 49 Hz (academic low basses), "standard" for contemporary music baritone starts from 110 Hz so you have to use around 3 foots (~0,78 metric meters actually, I am from "metric" country and do math in it) of absorption material for making it perfectly clean at least. Nothing personal, just physics and math All another options are marketing ******** (pardon).

I understand the complexity of linear broadband absorption (I studied it in college) and I agree that many of the claims by acoustic treatment manufacturers are hyperbole at best bordering on outright deception. But I think your application of the numbers is incomplete as it only takes into account basic absorption (STC ratings) without other complex factors like transmission losses (structural transmission, dissipation through air, diffusion, etc.), room geometry and subsequent phase interferences. Further, it places an undue amount of importance on linear broadband absorption when in fact diffusion plays a much larger role in the functional sound of a recording space. In other words, you can make a great sounding vocal room without using 1 meter of absorptive material if you intelligently balance absorption with diffusion. To apply that to this thread I believe the shape and materials of these reflection filters are capitalizing on diffusion more than broadband absorption.

 

[Dima B]

Some top engineers and producers (like Allen Sides, Jeff Lynn and Glenn Ballard) have recorded hit vocals and entire hit records in living rooms, bathrooms, and other unlikely spaces with little more treatment than a few packing blankets and rugs.

Because they know exactly what they want. And they book Abbey Road also. And any another studio which is suitable with a purpose. They can rent even public crapper for one percussion hit. I've never heard about any home-recorded, mixed and mastered Grammy-winning song.

 

[Dima B]

To apply that to this thread I believe the shape and materials of these reflection filters are capitalizing on diffusion more than broadband absorption.

So how they diffuse waves?