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

36 points by ghoomketu 3 days ago

50 comments

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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.

shadyfroyo 13 hours ago

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/...

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  • mcallaster 11 hours ago

    Seconded on MiniDSP being a great solution.

    You can have four different presets for different signal processing. The important part is that you can set them up how YOU want. Proprietary black box DSP parameters labeled as “night mode” or “movie mode” are hardly descriptive enough for my taste.

    It is also worth mentioning that if you decide to get a Dirac model/license, it is locked to the device instead of the purchaser. This is big deal for resale value, as many receivers lock licenses to the purchaser (and aren’t readily transferrable to new gear).

    I am a big fan of what they are doing in the space. I recently purchased a HTX from them for my living room and I have been as happy as a clam.

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not_your_vase 3 days ago

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.

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  • rollcat 11 hours ago

    > 2 - Use a PC for your video needs.

    I would like to second this recommendation. I've put my work desk in the living room; the 43" screen doubles as a (non-smart!) TV; instead of futzing with remotes I have a wireless mouse, an on-screen keyboard, and a macOS/iOS shortcut to switch the display between 2x (couch mode) and 1.5x (desk mode), which could also take care of audio routing, DND, lights, etc.

    Using a real mouse + virtual keyboard is so much faster than ANY remote I've ever used, and if you're not into clicking, you can type with a "real" wireless keyboard[0]. Another upside, is you get to watch things in the browser - with a proper ad blocker - instead of half a dozen confusing TV apps. Setting everything up takes a bit more effort than plugging a stick into an HDMI port, but it immediately starts paying off.

    [0]: https://www.microsoft.com/en-us/d/microsoft-all-in-one-media... via friend's recommendation, they have a very similar setup with a projector and MS Windows.

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    • yellow_lead 11 hours ago

      Ive been using KDE Connect for years now, on many different devices and OS. Highly recommend. Basically a remote mouse and keyboard on your phone. The latency is very good too.

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  • diggan 12 hours ago

    > 1 - Get an amplifier that has a "Night Mode" function

    Well, or get a compressor/limiter that you can jank into any signal chain, so you don't have to buy a whole new amplifier. You can find cheap compressors/limiters for like under $100 I'm sure.

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    • LM358 11 hours ago

      This would be a good option provided the source is stereo and either the speakers are active or the amplifier has a processor loop.

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randomfinn 12 hours ago

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.

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shermantanktop 12 hours ago

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.

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neom 12 hours ago

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

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  • alexjplant 11 hours ago

    At the risk of sounding like a hater there is _nothing_ "Rolls Royce" about a six-channel digital mixer that sells for $1200. No mic pres, tiny unlabeled controls, and six channels of God-knows-what conversion tied together with rudimentary functions implemented in a decade-old $15 DSP SoC is a toy. This is a device for generating Instagram likes, not a serious piece of A/V or music production gear. Under no circumstances should OP buy this.

    At least the Pocket Operators are reasonably priced and the OP-1 has some quirky uniqueness to it. The TX-6 is a brazen cash grab on par with their $1600 Ikea table [1].

    [1] https://teenage.engineering/store/field-desk

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    • neom 10 hours ago

      You know that meme with the guy sweating looking at two red buttons? That was me before hitting post on my original post, lol.

      I get it, but honestly, I actually think you're wrong about the TX-6, there is actually no comparable product to it on the market at all when you consider it's full end to end functionality, I also know one guy who has nothing else TE but sought out TX-6 because of it's pretty unique combination of attributes taking it's physical size/IO as part of the framing. I have a lot of their stuff because I enjoy it, but I do agree that everything outside of the OP-1, the TX-6 and the CM-15, are just toys. (The TP-7 is cool, but the most egregious all their products imo)

      I think this guy totally nailed it: https://www.youtube.com/watch?v=woiCEx5nWZY

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  • pimlottc 11 hours ago

    When it comes to hifi audio, $1,000 doesn't get you the Rolls Royce version of /anything/

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  • TylerE 12 hours ago

    No, that’s the Tesla Ctbwetruck version. TE is ridiculously overpriced and form over function. You can get way better compressors for a couple hundred bucks

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    • PaulHoule 12 hours ago

      I'd go get a pro rackmount compressor on Ebay first

      https://www.ebay.com/sch/i.html?_nkw=audio+compressor

      I had fond memories of using one at the KTEK college radio station where I was (first) the public relations officer and (later) the engineer. I was told we got it so that amateur DJs wouldn't saturate the transmitter. When I told my high school physics teacher (a classical music audiophile) about it I got a sharp talking to about how it hurts audio quality. Today I know it was an early shot in "the loudness wars".

      (If you're listening in a car or other noisy environment, dynamic range is a bug and not a feature, however.)

      6-channels would be enough for the typical 5.1 system but the "stereo" label on that expensive box makes it seem like it wouldn't do the right thing for home theater, where I think you'd want to reduce the gain in all 6 of the channel by the same amount.

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marssaxman 3 days ago

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.

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  • ghoomketu 3 days ago

    Thank you. Appreciate the reply. These gadgets are rather costly tbh. I did some digging around on YouTube for the compressor and I found this:

    https://youtu.be/d3XxckqoeXE

    Is it doing the same thing? Seems rather easy and cheap to make.

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    • marssaxman 3 days ago

      That is a clever design, and yes, it's doing the same thing. If you have electronics assembly skills, why not? Sounds like fun.

      There's no reason a simple compressor suitable for your purpose should have to be expensive; there just isn't much of a market for such a device.

      If you're open to used gear, another good option would be an Alesis Nanocompressor - available in the $70-$90 range: https://www.ebay.com/sch/i.html?_nkw=alesis+nanocompressor&_...

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ajb 13 hours ago

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.

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  • diggan 12 hours ago

    Not that OPs use case seems latency sensitive, but it can be good to know for others. If you go this route, you'd have to set things up very carefully as latency balloons up quickly if you pipe things outside>computer>outside. If you're just looking for reducing the dynamic range, cheap compressor for sub-$100 would do the trick without adding much latency.

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ulnarkressty 11 hours ago

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.

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bmcahren 12 hours ago

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

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msephton 12 hours ago

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.

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bestham 8 hours ago

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

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jitl 13 hours ago

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

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brudgers 2 days ago

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.

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  • duped 12 hours ago

    A limiter is a compressor with an infinite ratio. It does not clip.

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    • brudgers 12 hours ago

      Depends on the limiter.

      Hard limiters limit by clipping.

      If you look at the output waveform, I mean. It’s why limiters are sometimes used for distortion. The flat top and/or bottom create overtones.

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      • duped 11 hours ago

        I get that terms get overloaded especially when mixing between electronics, signal processing, and commercial products. But in the context of audio signal processing that would not be called a "limiter" - it's a clipper or clamper. You won't see products advertised as a "hard" or "soft" limiter - but you will see "hard clipper" or "soft clipper" used to describe that behavior.

        The distinction is that limiters and other dynamic range processors do not use clipper circuits/algorithms directly, they have an amplifier controlled by a feedback or feedforward signal path as the gain computer. The amplifier may create harmonic distortion, or harmonic distortion can be created if an envelope follower in the feedback/forward path is configured in a certain way, but it isn't the design or intention of a limiter to clip.

        Limiters can can clip if there's a clipper after the gain reduction which happens in some designs where the limiter is load bearing or uses a feedback path and no lookahead, but those are pretty rare these days since the entire point of a limiter is to avoid distortion.

        A good book that covers the design and theory of operation is Zolzer's Digital Audio Signal Processing. It's relevant even for analog designs, since the topology of the designs are the same.

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        • brudgers 9 hours ago

          Sometimes I watch studio porn on Youtube (multiply by a few years).

          Studios keep limiters in their racks for exactly the reason I describe.

          Just as they keep compressors around to add color.

          Your DAW probably doesn't emulate limiters that clip because it is not common practice (not Common Practice, either). But your DAW probably has compressor plugins that do distort because that's what people have heard about.

          In theory, an ideal limiter does not distort. Neither does a compressor. Or a mixer. In musical practice, an ideal device is often a bad idea. Musically we might want squelchy TB filters and CR1604 crosstalk.

          When you want to hard limit amplitude, clipping is the simplest thing that might work. And clipping is usually better than tinnitus.

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notatoad 12 hours ago

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

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NDizzle 11 hours ago

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.

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PaulHoule 12 hours ago

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

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  • memco 12 hours ago

    I know there have been multiple complaints that a theater in my area has the volume too loud. The staff reply is that it’s supposed to be loud. Gives the “you’re listening wrong !”vibes.

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    • ryandrake 11 hours ago

      Makes you wonder: Who actually wants this (the loudness)? Theaters (and sound mixers) must think it's more profitable to blow people's eardrums out. Are customers really demanding this?

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      • duped 10 hours ago

        This is an more interesting economic question than it might seem. The customers are asking for it, but the real question is "who is the customer?"

        The sound designers and mixers' customers are not the audience, it's the producers that hired them. They're also not creating just one mix, but up to one audio stream per every device and playback environment. The people that actually does that work is not always going to be the same as the ones doing the theatrical mix(es) or on the same timeline, and may be using a lot of automation to do it, or not doing it all.

        That indirection and the way that incentives get twisted can lead to really good or really bad content, but the quality of it isn't really indicative of how successful it's going to be financially.

        Good example of this is Wicked. Somehow, a musical in which you can barely hear the music, is clearing $700 million in the global box office and is going to be an awards darling. I have some suspicions about how the theatrical mix turned out so bad that has a lot to do with the economics of film production, but the gist is that whether something the audience thinks is "good" has nothing to do with what the producers paying the sound folks ask for.

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      • PaulHoule 11 hours ago

        There are the mixers and then there are the people who run the theater; the latter could set the sound to a comfortable and safe level.

        I know enough about sound engineering to wire up the board for a concert but I hardly ever do it because I think most events have the sound levels 10-20db higher than I find comfortable, anybody I work with will push the levels up when I turn my back. I think they're all deaf.

        In late middle age I know I'm finally slipping because I don't find hiss from tapes as offensive as I did in my youth.

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atoav 12 hours ago

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

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