I passed ACX's QC...but the end result sounds horrible.

I produced and published my first book with ACX, and am pleased that it is selling. I held my breath while the book went through QC and was happy to have it pass on the first try.

However, I was really surprised when I went to audible and listened to the clip. I sound distorted, almost muffled even. Convinced I was crazy, I went back and listened to the retail sample I submitted to them, and in it, despite a mild noise floor, there is no distortion.

Here is a link to the audible book to hear the clip: http://www.audible.com/pd/Science-Technology/Cognitive-Behavioral-Therapy-Audiobook/B01HFKR0FU/ref=a_search_c4_1_6_srTtl?qid=1466892600&sr=1-6

I attached what I actually submitted to ACX.

Is there something I can do in the future to help prevent this?

You may be too close to the work. I can listen to the ACX sample all day long without thinking there was anything wrong with it. How are you listening? Right this second, I’m on good, wide range, high quality Sennheiser headphones. If you’re listening on the built-in speakers of your laptop, I can see why you would think the work suddenly vanished. The resampled clip they offer is less crisp than your original.

I think your original has a little too much talking-into-a-wine-glass sound. That can be caused by excessive Noise Reduction and/or making a poor MP3. They usually catch that during the QC process, but yours is pretty subtle.

One personal preference, I think your submitted clip is too crisp and sharp, almost harsh. I think their version is easier on the ears, or at least on mine.

We know ACX resamples and recompresses the works for different products and services. They said so. This is where doing production in MP3 format just kills you. Each step in the production process causes the MP3 compression artifact damage and distortion to go up and you can’t stop it.

We recommend very strongly to do all your personal production in WAV (Microsoft) 16-bit—the Audacity default sound file format—and only stoop to making an MP3 just before you submit. I know some people think they need to do everything in MP3 because that’s what ACX requires.


There is a trick to submission.

be a 192kbps or higher MP3

192 is not a requirement, it’s the minimum. You can go higher than that.

You may upload 256kbps or 320kbps files if you’d like…

…and it’s recommended as long as you don’t go past the 120min chapter count or the file size limit…

Each uploaded file must be no larger than 170MB.

Those are all direct quotes from the ACX published specifications.

Submissions higher than minimum will help minimize distribution and product generation damage.


You may be too close to the work.

I don’t entirely disagree. After reading your post, I listened back to it through the phone I was on at the time (both to the sample and the original). I didn’t notice as much difference as I do when I listen with my headphones. Mine aren’t super studio quality, but are fairly decent pair of hyper X. It’s on my “to-do” list to get a better set of headphones, but for most purposes, these have suited me fine. I tried another set of headphones at my desk, and still felt like their clip seems distorted - room tone seemed a lot more noticeable to me as well. I wonder then, if it’s something to do with my computer. Not even sure if that’s a thing - I took a lot of production courses in college, but that was 12 years ago and I don’t remember quite as much as I’d like to think I do.

This is where doing production in MP3 format just kills you

I do my productions in audacity projects - unsure if this is best or not. I only export to MP3 only when I’m completely done with processing and ready to upload. I typically save my MP3 as 224 kbps and have never had an issue with sizes; albeit, I’m only working on my second official book with ACX at the moment. The second book is a novel in which I’m playing characters (versus the straight narration of the cognitive behavioral therapy book), so I’m mildly terrified their post processing will distort me.

I do feel better knowing it may just be me, however. Coming from a background in public speaking, I may desire crispness over warmth, and hopefully that is what is causing me to freak a bit.

Did you go through the clip submission and Audacity processing thing with us? Normally we do his with people who just can’t make ACX compliance no matter what, but I suspect you might benefit from a quick look.

Record a 20 second mono WAV clip and post it on the forum. Doesn’t matter what. Read the back of the Corn Flakes box. This is the format. You should only need the first sentence.


Do Not Change Anything. No filters. Don’t “help us out.” We’re after a raw “studio” clip.

I do my productions in audacity projects

One Project per chapter, right? That’s actually a little dangerous. Projects can be brittle and it’s relatively easy to lose work by accident. When you get to the end of a chapter (or logical dividing line) Export as WAV (Microsoft) and save it someplace safe. That’s your “Studio Master” against the time you accidentally turn your Project to trash and need it. Assume there is no reshoot. Bollixing up your edit so bad that there is no recovery and not having a studio master backup is extraordinarily bad form. I have WAV backups of stuff I shot five years ago.

Shooting work, saving it as a Project and then editing, filtering and processing that one Project to the final show is stunningly dangerous. Any accident or mistake anywhere in the process and you have no show. Boop. Gone.


Did you go through the clip submission and Audacity processing thing with us?

No - truthfully, I had never looked into much about varying techniques for passing compliance, since I passed with only basic edits. I’m moving my home “studio” space this weekend, so it would actually be great to do this on raw sound from the new area. I’ll post a clip once I get it all set up.

One Project per chapter, right? That’s actually a little dangerous.

Well, snap. I had no idea. Thanks for that. I’ll change the way I save immediately.

I’ll post a clip once I get it all set up.


I passed with only basic edits.

We tell people constantly, that’s what’s supposed to happen.

It’s not normal to need a laundry list of effects and filters to force your presentation into compliance. Twice now I walked into my quiet third bedroom and announced a compliant sound test with basic equipment and no other work than a volume change. It can be done.

I don’t want to frighten you away from using Projects. You can certainly do that, just it’s a good idea to Export each chapter reading as WAV and Export the final works as WAV before you Export for ACX MP3 Submission. Projects are lovely, but they only open in Audacity. WAV files will open anywhere.

Think of how you would feel if you were in the middle of careful editing a chapter and the computer crashed taking an important part of the Project/Chapter with it. Your computer doesn’t have to be unstable. You can just run the battery out. I know, right? That’s certainly never happened to me…

We recent had someone post who left his machine on constantly—as in forever—and never saved anything until the final work. His complaint was that the latest Disaster Recovery didn’t work as well as the older ones. You should not be depending on crash or disaster recovery for day-to-day work.

One last note about Projects. If you do save a Project, shut down the machine and open it all up later, the Project will open without UNDO. That can be a nasty surprise the first time you need Edit > Undo and it’s not there.


Twice now I walked into my quiet third bedroom and announced a compliant sound test with basic equipment and no other work than a volume change. It can be done

That’s more or less what I’m doing. I was recording at my desk (which I think is at least part of my previous “talking into a wineglass” sound), but I had literally nothing else going for me. It just happened to be a fairly quiet area. It won’t be now, so I’m stealing the third bedroom, and set up a little space in there to help drown out stuff and remove a bit of echo (as it’s literally an empty room). I just finished getting it set up today, and recorded a 20 second clip for submission and processing.

I wasn’t sure if I was supposed to submit it here or elsewhere, so I’ll attach it here and if I need to, just holler at me and I’ll be happy to put it in the right spot.

it’s literally an empty room

Our preference is a Victorian overstuffed parlor with lots of padded divans and reclining sofas and thick carpeting with heavy drapes. Ferns optional.

So an empty room is a good start.

I have a “portable studio” I made from sticks and furniture moving pads.

One finished wall is double layer.

Note the doubled-over moving pad on the floor on top of the industrial carpeting. This was a quiet room in one corner of our factory whose only shortcoming was bare-wall live echoes. I shot several animation voice tracks in that room. Note the contraption on the right is home-made vibration isolation for the microphone. Those are US Postal Service rubber bands.

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You don’t have to soundproof the whole room (although not a dreadful idea). There are a number of “announcing tunnel” concepts out there.
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Both of these are wrong because neither one pads the floor under the microphone and only the second one has a “spider” to isolate the box from the microphone. Metrobus rumble through the floor right up to the microphone in the case of the first one.

Also I would somehow deaden the wall behind you. The microphone is picking up your face and anything behind you. Alternately, put a corner of the room behind you, not a flat wall.

Fill the room with storage. Cardboard boxes full of old vinyl records and tax forms from 1982 are a terrific soundproofing. I did a sound shoot in a storage closet once—with the storage. I had to stop when the company ran out of room and turned it into somebody’s office. I actually time-shared with a Producer for a week or so.


I have to leave for a while. I’ll listen to the clip when I get back. Posting in this thread is fine.


The voice is angelic, but it sounds like you’re presenting in the same room with fourteen window fans all running at once. Turn up the volume in the first 1-1/2 seconds of that clip. Is that your computer ventilation system?

It’s loud enough that I can’t easily correct for it. I can get the blue wave peaks and the RMS (loudness) OK, but then I have to suppress the noise level and that throws the RMS off…and there starts the correction dance.

By the way, you violated one of the test clip rules. You decided to rearrange your pencils or clean our your bag or something in the first two seconds of the performance. I had trouble finding a pure, clean, silent stretch for analysis. That’s not “free time.” You’re supposed to be freezing and holding your breath.

Know anybody with a nice, quiet MacBook Pro you can borrow?


That illustration is from the ACX Training Videos. It’s remarkably similar to how I do it and if my studio was less messy, I’d post a picture of my own. Koz

Turn up the volume in the first 1-1/2 seconds of that clip. Is that your computer ventilation system?

It’s not actually - I stole a buddies macbook to record in there (while hemming and hawwing on the decision to get my own). I typically turn off the A/C in the house to record, and I believed I had it off, but listening back I’m wondering…

I have a “portable studio” I made from sticks and furniture moving pads.

Nice! I built a frame out of PVC pipe to make what comes out literally like a blanket fort. But it works!

Post pictures. I’m tired of being the only one on the block with a fort.

You can get a Mac to make noise. If it thinks it’s getting too hot, the fan system will kick in. I was reading a nice news piece and the site was building a massive animated commercial in the background. The system went into high gear and in a minute or so the fans went nuts.

The fort worked. I could not tell how big your room was by listening.

Sit in the fort quietly for a minute and then shut the Mac down. Did the gentle background whir go away? Listening for this stuff is a trick.


Another way to do it is pick up the MacBook while it’s running, turn it around and listen to the back of the screen down close to the hinge. That’s where Macs do most of their air exchange.

Is it an older 13" MacBook and not Pro?

Apple (upper left) > About This Mac > More Info.

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Pictures ahoy:

I just used baffle-boxed down blankets, but so far, so good. Considering making it less long in the back, so the back panel is a lot closer to me? Unsure of how much it will help.

So yesterday I swapped out laptops, and then attempted to record without a computer entirely. It was a janky old recorder that I used, but even with the a/c and the fan off, I’m still getting some loud as hell hum. I legitimately don’t know how I missed it on the first run through, except that my volume was down, perhaps. I even checked to see if a neighbors air conditioner was particularly loud, and got nothing. No other major appliances running, except the fridge natch, but its three rooms away and not loud to begin with. I’m a little stumped on whats screwing my noise floor.

It’s a sorta relief it’s not the Mac causing problems. That’s been the go-to machine for quiet, well-behaved recording.

Unsure of how much it will help.

Not at all. Leave the larger space. I assume you did not glue it together? I’ve been known to not use glue so the whole thing knocks down into a little pile when not needed.

You accidentally invoked a physical noise reduction process more complex than just a blanket. Your voice has to leave the booth through the duvet (step one) travel to the nearest wall (step 2) reflect from the wall (step 3) travel back to the booth (step 4) go through the duvet a second time (step 5) and then travel to the microphone (step 6). Each step reduces the volume of the echoes and room effects. So it’s no wonder I can’t hear the room in your recording. It’s not there.

You did miss (I’m guessing) the heavy towel on the table under everything. That towel solves many noise problems.

Are you always using the same microphone in these tests?

Are any of these setups even remotely portable? If the source of the noise is not obvious, you may need to go on a noise hunt.

Put headphones on, turn everything up. Start Audacity recording or put it in monitor mode (scroll down)


and walk the microphone around the room, and around the house if needed and listen for the noise to get louder. That’s how I found a “leaky” amplified bass cabinet which was humming even when turned off. I put the microphone on the end of a stick and kept moving it until the noise went crazy.

We have had posters with magic houses. Step out the front door and the hum vanishes. Gone. Even better, walk around some of the rooms and the hum will come and go depending on which corner you were in and which way the microphone was facing. No pattern. That’s classic resonance. The room or the whole house really likes the tone that perhaps a power transformer or some other motor or other noisemaker is making. That’s the guitar body or violin body thing. Without the body, a guitar string doesn’t sound like anything. Touch an empty box to the vibrating string…

Keep us up. This is better than a soap opera.

Orchestra up… and under.
Will Marie find the mystery hum? Tune in tomorrow.
Orchestra up… and out. Commercial.


I assume you did not glue it together? I’ve been known to not use glue so the whole thing knocks down into a little pile when not needed.

Yeah, I only glued a few joints to keep it sturdy when I’m going in and out of it. That way it can break down quickly should I actually need the room for a person.

That towel solves many noise problems.

I do have a towel, but today on reading this, swapped it out for a thicker one and double it over.

If the source of the noise is not obvious, you may need to go on a noise hunt.

Okay. I investigated, I futzed around, and I’m pretty sure the hum is shared between two things: the radon mitigation unit in my house (good old midwest and the damn radon), and a transformer/multiple electrical boxes in the backyard.

You can see in the pictures of my blanket fort theres a window - that whole wall faces my backyard, and that corner is right where my radon mitigator vents to the outside. Unfortunately, every “free” room in my house faces the backyard, and so will get both hums to some extent. I can trip the breaker to the radon unit to lower the noise. When I did so, I went from -57 to -59/-60. The static hum is still there, but the louder component to it (and the bit that occasionally jumps to -50) is gone.

I did like you said and took my getup from room to room. I watched my waveforms and recorded about 5 seconds of free tone in each room - the rooms on the backside have the worst of the hum, as does the actual backyard, so I’m not free of it when I leave the house. The rooms on the frontside are mostly free of the hum, however, because they catch every bit of street noise/children playing/people mowing.

It’s good to know what it is - but its a pain in the ass to know its not something I can do much about! I have a 15 minute clip due tomorrow, and was hoping I’d figure out the mystery hum and be able to launch it into orbit and have a nice, hum free experience for the next book.

Radon as I understand it, slowly seeps from the soil and accumulates over time. It’s worse if you have a dirt floor basement, but much less of a problem with a paved or finished basement. So it’s not a “turn the pumps off and everybody dies” thing. I don’t think temporarily turning it off concerns anybody (except possibly the company liability thing).

Post another voice sample with it off. Good to do that every so often as a reality check.

I think we can Noise Reduce you into good submissions, we just have to be careful. Having noises come and go is probably the worst problem. ACX “helpfully” tells us to stop recording when the noise is present.

Thanks for that. Really.


I may have a solution! I had the same issue where my samples all sounded horrible and muffled… Nothing like the audio files I exported from Audacity. I checked my audio settings within GHub (The software for my logitech headphones) and the muffled sample issue was immediately resolved when I turned off surround sound.