Ask HN: Seeking device to normalize audio output for consistent volume levels

Hello hn. I'm looking for a device that I can insert between the audio output and speaker to normalize the audio.

The goal is to ensure that sudden loud noises don't become overwhelming and quieter parts sound reasonably the same.

My reason for doing this is because it's so hard to watch movies these days because of the inconsistent volume levels (2x harder at night).

Any suggestions or recommendations on specific products or solutions would be greatly appreciated! Any DIY suggestions are also welcome too.

You’re looking for a compressor.

Lots of pro audio boxes out there.

A MiniDSP box where you can implement a compressor is fun, you can also tune just about everything else with it.

https://docs.minidsp.com/product-manuals/flex/dsp-reference/...

13 hours agoby shadyfroyo

1 - Get an amplifier that has a "Night Mode" function. It has been a basic function on most AV-receivers in the past decade+, assuming you don't buy the most pedestrian model. It compresses the dynamic range of the sound, to avoid the loud parts waking up the neighbors while you can also hear the conversations. Of course here you are looking for an investment of between $350 and $inf. Buying secondhand can save big bucks.

2 - Use a PC for your video needs. Most video players support the same function (VLC, GOM player, Kodi... look for "dynamic range compression" and similar options). A 10 years old mid-tier machine will play everything including UHD, so this solution is fairly cheap. If you get a cheap IR-USB remote, you won't even have to mess with keyboard and mouse.

2 days agoby not_your_vase

If your source is Dolby Digital, you may not need anything new - just adjusting your settings. Dynamic range compression is a standard feature, and the bitstream should already include the necessary metadata for the decoder to implement this.

It's been a while since I looked into this in detail, but iirc the decoder must automatically enable dynamic range compression when it's set to two channel output. So avoid configurations where you first convert the audio to 5.1 channel PCM or analog, and then apply downmixing or virtual surround.

If you're using a surround system, most receivers have a night mode as mentioned by others already. Some have also an adaptive system that adjusts the dynamic range based on your volume setting - turn it up and you get the full dynamic range, turn it down and the dynamic range is compressed more as you set the volume lower to try to keep the dialog audible. Many receivers include a microphone for automatic settings, and after calibration know the actual output level. The Dolby Digital bitstream (and I think DTS) include a flag to indicate the overall dialog level, and based on these a receiver can do quite a good job. Some I think go only by the DD metadata, others have a compressor that can be applied to any input.

13 hours agoby randomfinn

And just in case for fun, you want to know about the other end of the spectrum from the recommendations you'll likely get, here is the Rolls Royce version of what you're asking about: https://teenage.engineering/store/tx-6

13 hours agoby neom

This kind of device is called a "compressor", and they are ubiquitous in recording studios. They can get very expensive and complicated, but for your purpose something like this may suffice:

https://www.amazon.com/rolls-SL33B-Stereo-Program-Limiter/dp...

Specifically what you want is a "stereo compressor" or "compressor/limiter"; if you want something more sophisticated than the device above, there are many 1U rack options available for ~$200 (dbx is a good choice), or used on reverb.com more like $70-$100.

3 days agoby marssaxman

FYI, the place to put such a device is definitely not between the amplifier and the speaker. You want it on the audio input to the amplifier.

Unfortunately modern receivers have preamps that do a ton of digital decoding, input switching and other stuff, making the audio signal between the preamp and the amp impossible to get to. That leaves you with receiver features like night mode, as suggested by others.

13 hours agoby shermantanktop

This can be done in software, eg https://askubuntu.com/questions/31580/is-there-a-way-of-leve... for linux.

I guess that you're asking for hardware because the source device is not under your control. In theory you could use any device with a line in to process the audio. However for watching movies that may be suboptimal as any significant delay would cause lipsync issues. That's probably something you need to check for in any solution.

14 hours agoby ajb

I have the same issue with late night talk shows / live comedy shows where the audience cheering is way louder than the host's voice. At some point I tried an AI model to detect and lower the volume of these parts, but didn't get that great detection with the limited training dataset that I labeled manually. IMO Youtube or other streaming platforms should offer this option.

12 hours agoby ulnarkressty

Your TV, amplifier, or sound bar should have a night mode that does this for you.

13 hours agoby bmcahren

I'd be surprised if your setup didn't offer this already. Both my Apple TV and surround sound speakers system offer it. My TV, too but I don't use that for audio out.

That said, at night I simply use headphones.

13 hours agoby msephton

The stations should have this on their end really.

https://www.ebay.co.uk/itm/285621756629

12 hours agoby butterknife

VLC used to have a built-in compressor as a plugin by default. Try it and see what you think.

9 hours agoby bestham

https://imgur.com/a/FVjuLtz

12 hours agoby bookofjoe

AppleTV has a seeing to do this if you’re using one of those.

14 hours agoby jitl

A limiter limits the maximum power. Some are hard and will clip. Some are soft and will produce a milder distortion.

A compressor compresses the dynamic range. They reduce the sounds about a selectable threshold with variable ratios and envelopes. Usually they have various other features.

This compressor/limiter/gate/expander/de-esser has more features than you are likely to use soon (side chaining) and will almost certainly sound good enough (despite what people may comment in response) [1].

https://www.sweetwater.com/store/detail/MDX2600--behringer-c...

Good luck.

[1] If it doesn't you can spend more later if it solves your problem. The nice thing about these compressors is: they have transparent bypass, a dedicated power button, robust construction, mature design, and are cheap.

2 days agoby brudgers

I just gave up and started using headphones at night

13 hours agoby walthamstow

my Sonos Beam soundbar has "night sounds" and "voice booster" modes that do an excellent job of solving this problem.

13 hours agoby notatoad

do you have a sound bar at least?

13 hours agoby guy234

Maybe it's because I'm a bit older school, but I turn these kind of things off traditionally. In my experience they degrade sound quality. There might be higher end (or the technology made its way down to affordable) that don't degrade the quality, but I'm not taking any chances with the amount of coin I have put into my setup.

12 hours agoby NDizzle

It's been a problem w/ Hollywood movies since "home theater" came out. That is, a really boomy soundtrack adds to the emotional impact when you are in a closed room but in an open space where people come in and out (where there average TV is) it's totally inappropriate.

Systems like Atmos that decompose the sound track into components might help but they're likely to get used for the wrong reason -- in the last 10 years Hollywood gave up on making the vocals in movies legible, which has the positive effect that a lot of people are used to reading subtitles, which is why you can find subtitled anime [1], Italian crime dramas [2] and such in downmarket places like Tubi these days.

(Maybe it's why my acting coach who yelled at me to enunciate the same way my wife yells at horse riders to keep their heels down is here and not in LA)

[1] https://tubitv.com/series/2082/accel-world [2] https://tubitv.com/movies/571052/mafia-millionaires-subbed

13 hours agoby PaulHoule

What kind of device do you use, what kind of speakers? If I were you¹ I'd first look for a software fix (dynamic range reduction or compression). If you really want to go for a device I would skip all musician-advice and buy some sort of DSP like the t.racks DSP 4x4 Mini Pro that has compressors, equalizers and delay compensation on board and is programmable via a GUI.

But already over-compressed stuff like music will sound worse that way, so in your position I'd prefer a software fix that is limited to movies.

¹: I am not, I like dynamic audio

13 hours agoby atoav

Dolby Digital

13 hours agoby mitnichiter