A Poor Man’s Vocal Booth?

Sometimes I come across a certain product and wonder:

It looks promising, but is it any good?

The CAD Audio Acousti-Shield 32 is one of those things.

Designed to “substantially reduce unwanted reflections, echo flutter and environmental unwanted acoustic interference,” does it deliver as promised?

At about $85, could it be the poor man’s vocal booth, or is it a waste of space, and money?

SOUNDPROOFING

Before I tell you what I think, let’s briefly discuss the whole concept of soundproofing and room treatment. As I wrote in my booklet Building a Vocal Booth on a Budget:

“In this noisy world, soundproofing has become big business. I just Googled the word and got almost two million results. Buyer beware, because the same search will take you into the realm of grotesque claims and pseudo-scientific truths:

“These Soundproof windows will totally eliminate your noise problems.”

“This soundproof foam absorbs up to 66% of sound waves.”

“Our soundproof curtains offer the highest STC performance.”

Do the makers of these products assume we’re that stupid? Think about it for a moment. What does “soundproof” really mean? Most dictionaries describe it as:

impervious to, or not penetrable by sound

Going by the aforementioned claims one could argue that the minds of the makers of these products seem impervious to, or not penetrable by logic. Then again, advertising is all about making noise and not about offering sound proof.”

Gluing some acoustic panels to your wall or on to a “shield” will do nothing to block outside noise from coming in. Auralex foam and its many clones will change the characteristic of the sound inside your recording space, diminishing reflection and reverberation. It absorbs the sound but it does not reduce it.

Yet, CAD claims that their shield can substantially reduce “environmental unwanted acoustic interference.” What does that mean? Would this shield be able to diminish ambient noise? Why not find out? For the test, I purposely chose one of the worst acoustic locations in my house: my basement.

TESTING

Let’s say you want to use your laptop for a quick recording and you place your microphone in the same room. Before you know it, the computer fan kicks in and starts making noise. Could CAD’s Acousti-Shield magically neutralize the noise? 

I’ll let you listen to the same script twice. You might want to put your headphones on. First you’ll hear my voice without the shield in place. The second time I read the script, the Acousti-Shield cradles the microphone. Just notice if this device is able to get rid of the noise the laptop fan makes.

 

That’s pretty clear, isn’t it? It confirmed my suspicion. The shield does very little to keep unwanted noise out of the recording. As expected, this thing is no substitute for a properly isolated room. But will it deliver on the second promise? Could it make a room sound more dry? 

Before I play the second soundbite, you should know that I recorded the audio with an AKG C 3000 B microphone, plugged into a Grace Design m101 preamplifier. The 16 bit, 48,000 Hz WAVE recording was converted to MP3 format for this blog.

For the next track I removed the laptop from the room. Once again, you’ll first hear me without the shield. Then I’ll read the same text with the Acousti-Shield 32 in place.

 

Did you hear a significant difference? A difference worth over one hundred dollars? To be honest with you, I was disappointed. The room didn’t sound dry to me at all. How could a company with such a good reputation bring such a poor product to market? It just didn’t make sense.

WRONG APPROACH 

The next day I woke up with an idea. What if the product wasn’t the problem? Perhaps I was not using it properly.

I went on a few online forums to find out what others thought of the Acousti-Shield, and I found my answer. The recordings you just heard were made at 9 inches from the microphone. What would happen if I would come closer? 

Once again you’ll hear me read the script twice. First I’ll read it at 5 inches from the mic. Then I’ll add the shield, and keep the same distance.

 

Now, this is more like it! Distance makes a huge difference.

Thanks to a clever design, you can also move the microphone closer or further away from the 53mm high density micro cell foam. This obviously changes the acoustic result.

The question remains, would I recommend using such a shield for voice-over recordings? Let’s first look at the positives.

PROS and CONS

The Acousti-Shield 32 is well-made and easy to assemble. For its size it is very light, and unless you have a cheap mic stand on which to mount it, it won’t tip over. Compared to a product like Harlan Hogan’s Porta-Booth Plus ($189), it is affordable. As long as you stay close to the mic, it manages to tame unwanted reflections.

Here’s what I like less. CAD’s Acousti-Shield is not a unique product. sE Electronics was one of the first companies to come out with such a solution. They called it the Reflexion Filter X. Although I haven’t tested it, it looks very similar.

Unlike Harlan’s porta-booths, the CAD shield isn’t very compact. It’s meant for the studio, not for the road. Even though the shield accommodates a variety of microphones, a popular voice-over shotgun such as the Sennheiser MKH 416 does not fit.

Here’s the big one: where to put the voice-over script? 

I’m usually reading my copy from the monitor in front of me. The CAD shield would block my field of vision. Even if I were to read it from a tablet or smart phone, there is no place to put them as long as the shield is mounted on a mic stand.

In the end I came up with a simple solution. I put the shield on a flat surface that was resting on an old loudspeaker stand. With the microphone on a table stand, there was room for my Nook or iPhone. 

EXPECTATIONS

So, is this shield a good investment?

In the end it’s all about expectations. If you get the Acousti-Shield 32 because you need a portable studio, you’re not going to be happy. If you need something to keep ambient noise out of your recordings, this is useless. 

However, if you cannot acoustically treat the room you’re in, and you’d like your recordings to sound more dry, this is an affordable solution, as long as you know how to use it. 

Paul Strikwerda ©nethervoice

PS CAD Audio kindly donated an evaluation model to the author of this blog. Though very much appreciated, this did not influence his opinion.

PS Read more on taming unwanted reflections in “Get the boom out of the room.”

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  3. This was a helpful and pretty funny review. I’m starting to see that not all these things are created equal. I own a Soundkitz AE-F that I use pretty much wherever. It was a night and day difference but I think the difference with the Soundkitz AE-F is that it has a filtering system to help process your voice. The acousti shield doesn’t. That’s probably why it did so little to help.

  4. Paul, good read and I learned a lot from listening to your tests a couple of times each. Very educational!

    Paul Strikwerda Reply:

    Good points, everybody! I can see a role in a recording studio for shields like the one made by CAD. Artists like Sting have used the sE Relexion Filter. If you don’t need a twenty-page script in front of you, it’s much easier. As Monty suggested, using a super-cardioid microphone instead of this shield, is a better solution for voice-overs. I also like Harlan Hogan’s Porta Booth PLUS which has a slot in the back through which you can stick your shotgun.

    Definitely worth mentioning is the “Studio Suit,” developed by Dan Lenard, the Home Studio Master. It’s a low-cost and very effective sound-dampening solution made from recycled material. Check it out!

  5. I have such a screen, although from another brand, DAP Audio. It works best if you put it in the corner of a room, with the mike as deep as possible into the screen (no shotgun), and with your lips as close to the mike as you can. Mind you, as the article says, it doesn’t remove unwanted sounds coming from elsewhere. But it does make the room sound “dry”. Another thing. If you need to scream, turn the level on the preamp down and stay close to the mike. But even then, the waves coming out of your mouth will probably be too strong for the shield. So I think it only works well on soft to regular voices.

  6. Hey Paul,

    You are just great!

    I have a Porta-Booth to carry when I travel, but it helps only if the enviroment is already quite enough 🙁

    I have also a shield like that, that makes — as you proved — little difference. So, I’m reselling to a colleague who already has a booth, but a big one, so this will bring him — little — but better results.

    And to be honest… As my booth is so small… I didn’t like to sound too dry 😛

    THANK YOU for sharing this with us!

  7. I think this could be a decent solution in conjunction with some other simple sound-proofing precautions. ( Mary Catherine Jones had a great idea with the sound blankets. ) The most important thing to keep in mind is that it is rare for any one product to be a be-all-end-all panacea to any problem.

  8. I had a feeling I knew what you’re review was going to be before I read it…only because these sorts of things, no matter how good they may be, are still no substitute for good acoustical treatment and soundproofing. Do I get the impression you prefer Harlan’s Port-a-Booth over this?

  9. You completely rock! This is how you evaluate a product so people can make educated decisions about products in the marketplace today. I’m deeply envious that you get to try out all the cool products. Paul “Underwriters Laboratory” Strikwerda. Need a lab assistant? oh darn, I’d have to live in the US! 🙂

  10. Once again good post Paul. The effectiveness of this type device will also depend on what style of mic you are using of course. Even if you are at shorter proximity than your 9 inch example, when using a Sennheiser 416 or even Rode NTG 3 for example like I am- the sheer fact that it is a shotgun mic, long and slender will put it past the area of protection that this device claims to offer. I have a very similar device and it now stands as a conversation piece in the corner of the studio- and nothing more. I only purchased it because my audio system was behind the soundbooth, and the mic I used before still picked up a bit of fan noise. I put this inside the booth as a means to help lower that noise from behind the mic. With the mic I had before made by Blue, and the fact that it was not a shotgun mic, was picking up the fan noise a bit. I found that with the Rode NTG 3 I no longer needed it due to the mic’s pickup pattern. Thanks again Paul for quality information.
    Cheers

  11. Before buying a home built in 1962 with a fallout shelter and foot thick concrete walls (and building booth within), I had ambient sound issues in an apartment. A video guy I work with suggested buying sound blankets, used on video shoots to cut down noise. They do work and you can put together a booth of them on a wooden frame. Soundproof? No. Better? Yes.