Beginner's question about room acoustics for spoken word

Motivated by the Corona/homeoffice/teleconference/remote training situation I am exploring all things audio/video production.
Aiming for Podcast-style narrations of content related to my job.

Regarding the “audio” aspect I am under the impression I should maybe start with the room acoustics – at least to get some quantitative idea about my mancave’s setup.

Is this a good approach?

  1. I downloaded some white noise from a random source I found
  2. also dug out my movie-production type of clapper
  3. hooked up a SM7B (I feel kind of committed to all this g) to a DBX 286s (see before) into an older Focusrite Saffire 6
  4. recorded abrupt (and even clipping) noises with Audacity
  5. and used the dB scale of the tracks to get an idea about the duration

A picture of the room and the waveforms in audacity can be found here, in case someone finds such beginner’s questions amusing enough to care.

The reason I am asking is that despite some “fragmented” surfaces in the room like an open book shelf (but also “hard” closed cupboards) the return seems rather fast. Too good to be true?

(Obviously a spoken word sound recording will also give some qualitative idea, but I don’t feel that confident yet.)

I have two favorite bad examples. Early on, someone went to great pains to build a simulation of a television news set. It was impressive with colors, angles, and lighting just right. The effect carried right up to the first time somebody said something. Instant kids recording in the bathroom.

There is a current explainer show where the performer followed every tutorial for color key, background gradations, and expressive lighting. He, too, looks grand, but sounds like recording in a kitchen.

I love the SM7b, or as I call it, Joe Rogan’s microphone, but it does have one problem. It’s a close-talking microphone and tends to lose it’s moxie as you get further away, particularly if you have a shaky studio. Did you get the Lifter with it? Very Highly recommended.

Are you going to stick yourself sitting at a desk with a large microphone in the picture? You can do that, but it should be a conscious decision at the beginning, not something you got forced into.

We’ve been using lavalier microphones for decades because they’re not intrusive and they work pretty well in a quiet room.

I recognize hiding behind the technology when I see it, but you really have to say something into a microphone.

Follow this recipe.

https://www.kozco.com/tech/audacity/TestClip/Record_A_Clip.html

Koz

Teleconferencing has its own problems. Step one. Everybody should be on headphones. The less correcting, patching, and filtering you force the conferencing software to do, the better. This tends to go around people because you are wearing headphones so your voice sounds terrific to everyone else. They’re wearing headphones for you.

That in addition to quiet room, no echoes, no traffic noises, etc

Do not put a bright window behind you, and try as much as possible to talk to the camera.

No, you can’t record both sides of a conference.

Did I cover everything?

/rant

Koz

There are de-reverb plugin$, which can mitigate reverb if it’s mild.
(If it’s like a tiled bathroom they’re not going to help).

ACONdigital DeVerberate is the cheapest I’ve seen, but it’s still ~$100.

Minimal soundproofing calls for deadening opposing surfaces. Floor, North Wall and West Wall for example. That will do an amazing job of killing the worst echoes. It will still be a “live” room, but it won’t have that Kitchen or Bathroom sound.

There are methods of cheaply sound proofing tiny locations, but your job description calls for a “studio,” not a box you stick your head into.

You can do very well with Furniture Moving Pads.

You can do that with plastic pipes, too.

This is the plan for a kitchen table sound studio. Modest size is relatively easy. Trying to soundproof a room can be challenging.

https://forum.audacityteam.org/t/too-compressed-rejection/52825/22

This is a full-on portable studio for a movie sound shoot. Each of those is double. Note the moving pad on the floor.

That’s a Mac, so it doesn’t make any noise.

Yes, that is a home-made microphone shock mount. Genuine Postal Service Rubber Bands. Accept no substitutes.

Koz

OK, I pick it up from here. English is not my native language though – but “challenge accepted”.
You want me to post these 10 seconds, right? Please find SimpleAudacityForumVoiceTest_2021-0225.wav attached.


Until today I was always under the impression that here in Germany we only have the cheap moving blankets, but trying harder today I found these premium quality ones as “furniture storage blankets”. Until today I was fearing the sewing machine had to come out…


To clarify:
I want to improve the room at home for “just audio recording”, for pre-produced parts of my workshops/trainings without any talking head.
The room at work is close to a bathroom acoustically, there I am using either bluetooth Plantronics Voyager Focus headset, a Rode NT USB or a Rode Lavalier GO. Out of convenience I use the Plantronics most of the time. Indeed that room is more studio-ish with HDMI switcher and stuff.

My question is: Am I right that the room acoustics as-is are somehow acceptable? When I tried this RT60 test I suspected that I do something wrong, because the sound ‘died’ rather quickly.

I want to tackle the room acoustics first – next step will most likely be the chronic sinusitis :wink:

koz has apparently stepped away, but I am sure he will be back soon.

Koz is probably fast asleep, or just waking up - he lives in Los Angeles :wink:

Peter.

he lives in Los Angeles

It’s easy to forget that the forum is active over 9 time zones. So when it’s noon in Stuttgart…

I was catching a few early morning waves off Docweiler Beach. Not surfing or anything, just watching them from a respectful distance.

It doesn’t say so in the instructions, but we can get nearly all the value from the sound test in any language. You don’t have to be theatrically perfect in English.

I don’t hear anything wrong with the voice. No room reverberation or echoes. Any change you might want to make can be made with acting and vocal emphasis. You don’t have to start moving walls around. I like the voice and could listen to a story like that. A ghost story.

What’s that moaning sound in the first two seconds? We discuss echoes and reverberation at great detail, but you can’t have traffic noises, refrigerators, ticking clocks, or jets going over. I have all of those things. I can tell you what the time is by when the Metrobus goes by.

The loudness is almost perfect. I applied the Audiobook Mastering tools and the sound passes ACX testing.

Screen Shot 2021-02-26 at 9.29.02 AM.png
Except for the moan.

Koz

Thanks a ton for the feedback!

In the meanwhile I did indeed do a small modification of the wall I am speaking into:
https://imgur.com/QTGkpit
But as I need to also hang a projector in that spot it will take me a second attempt to “nail it” – drywall ceiling vs structural weight bearing capabilities vs wife acceptance factor require further refinement! :wink:

Will focus not on the room though – rather my client proposed a specific project so “content” is now my main priority.

If you have a construction option, don’t make the walls straight. There was a “studio” at a place where I worked which only had thin industrial carpeting on the floor and I don’t remember any acoustic ceiling. Plain painted walls. But the walls weren’t parallel to each other. If you were paying attention, the ceiling was a little closer to the floor on one side of the room, so it wasn’t parallel with the floor.

It was a remarkably dead room—no echoes—and I sent several sound recording jobs through there.

Another location I had an office with perfectly aligned walls and ceiling. I could clap my hands and go to lunch and the clap sound would still be bouncing between the walls when I got back. I didn’t record anything in that room.

Koz

There may be a movie trick with your SM7b. Suspend it over your face just out of camera range. The “official goal” is 46cm up and 46cm forward. When I learned it, that was a foot and a half up and a foot and a half forward.

Screen Shot 2021-03-13 at 06.35.05.png
You didn’t say whether you got the Cloud Lifter with your SM7b. If you use the microphone suspended, you may have trouble making noise-free recordings. The SM7b is excellent, but not a loud microphone.

https://www.sweetwater.com/store/detail/CL1Cloud--cloud-microphones-cl-1-cloudlifter-1-channel-mic-activator

If you do get a lifter, your microphone preamplifier or interface must be able to supply 48 volts phantom power.

Screen Shot 2021-03-13 at 06.43.52.png
The lifter uses 48 volts to work. We note that the SM7b does not use phantom power, so it’s a good marriage.

Koz

I have the European version of the Cloudlifter, the Dutch FetHead. Used it in that sample recording.
Their form factor is great, almost not noticeable between microphone and cable, right on the boom pole.

And at work I have now a entry-level lavalier mic, by the way – your suggestion did not go unnoticed.

With the room now “ticked off” I am indeed now looking forward to some experiments with mic placement and " personal EQ profile ". Hypothesis is that my chronic sinusitis might be slightly concealed by a mic placement from above, and at an angle to counter plosives.

These Beyerdynamics DT770 Pro certainly help with the evaluation! Before I had “HiFi headphones”, unbelievably (in hindsight) heavy in the lower range! Can’t stand the bass now, and they were even sightly more expensive.


My wife fortunately is quite accepting of all this. Even actively interesting in recordings of her own voice. Perdonally I haven’t given up on the idea that she should start a podcast in her native language, to convey her professional knowhow (I contributed to the brain drain in her native country by migrating her inter-continental).