Hacker Remix

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

39 points by ghoomketu 3 days ago | 49 comments

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 14 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/...

madphilosopher 1 hour ago

A compressor is the right answer. If you lean toward more old-school audio engineering, I would recommend one of these compressors:

* Alesis 3630

* DBX 166 or 266

* FMR Audio Really Nice Compressor

Explore the various demos on YouTube to see what these are about. The compressor goes between your audio source and your amplifier. I personally use the Alesis 3630 for normalizing the audio in my ham radio transceiver setup.

mcallaster 12 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.

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.

rollcat 13 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.

yellow_lead 13 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.

diggan 13 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.

LM358 13 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.

randomfinn 13 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.

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.

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.

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&_...