Any audio-savvy folks around here?


#1

Once I get away from my sound card I need some help. When is Dolby/DTS preferred over PCM?

Here in rural Alabama we use the finest in mediocrity. I have my PS4 connected via HDMI to a Vizio TV. I then use TOSLINK to connect to a Vizio 2.1 sound bar.

Under the audio settings, the PS4 has Audio Format (Priority) with selections of LPCM, Dolby, and DTS. Last night I tried Bloodborne with both LPCM and DTS and really didn’t notice much difference. If anything it seemed as though bass was slightly deeper with LPCM.

The TV itself has audio options for PCM and Bitstream. It says that you must select bitstream in order to use more than 2-channel audio. Selecting bitstream on the TV lights up a Dolby “Double D” light on the sound bar but I really can’t tell any difference in sound quality.

I guess the question is – For 2.1 audio, is PCM or DTS the preferred format? All of my Google searches brings up posts from 2008 and mainly concerns 5.1 setups. I do have the sound bar trying to faux-surround sound if that makes a difference.

My primary Vizio TV in the living room has a 5.1 setup. I think I have finally set that up to produce slightly above mediocre sound. I set the TV to PCM there (which is opposite what was stated in setup).

I don’t think any of these devices can use DTS-HD or any of that new fancy stuff.


#2

Seems like I found the answer to my own problem. My 2.1 sound bar has DTS TruSurround and Dolby Digital decoding. If I understand TruSurround correctly, it will take the compressed Dolby 5.1 signal and properly process it as virtual surround for my 2.1 system.

So I think if I select Dolby bitstream on my PS4 that should be the best option. Also, choosing bitstream on my TV makes that nifty Dolby symbol light up every time I change channels. That makes me feel warm and fuzzy.


#3

I was expecting @Auth to jump in, maybe he hasn’t seen it yet. I believe he’s an audio engineering type.


#4

I was sleeping in :wink:

This question actually has a few layers to it that require consideration on a case-by-case basis (based on my understanding of it, which may not be complete).

PCM (Pulse-code Modulation) is uncompressed, lossless audio and the new kid on the block (of the 3); Dolby Digital and DTS are both compressed, lossy formats. From a pure audiophile standpoint that puts PCM ahead in the game, but there are a few additional factors that can still cause it to be less-than-optimal.

Depending on the age of your gear, what it supports, and what it was designed to play nice with (along with who was in charge of mixing down each of the formats and how well they did on any given medium) will ultimately determine the best user experience in spite of the above-mentioned compression differences. Because you’ve got a device that appears optimized to run with one of the Dolby formats, that may end up providing you with the best user experience; if you were using an unbiased setup that didn’t specifically lean to any of the 3, PCM would likely win hand-over-fist (provided, again, that the sound engineers in charge of each mix did their jobs equally-well).

There are lots of moving pieces and I recommend you spend some time with various Blu Ray movies, games, etc. and try them on the different formats through your specific system. Some people don’t like driver-based surround simulation because it can have a tinniness to it or be missing clarity in the extreme percussive points (gunshots) or highs (generally the lows are a nonissue if you’ve got a subwoofer) but many people don’t notice or care (and these are not near as prevalent on a sound system as they are in headphones, oftentimes); some people can’t handle the knowledge that they might not be getting the absolute purest form of sound, even if they can’t distinguish much or any difference between the formats (generally, there are the types of folks that buy sound cards for their computers rather than just using the onboard sound they’ve already paid for that comes on their motherboard); and others have something akin to brand loyalty and “because movie theaters use Dolby or DTS (etc.) it’s clearly the best” whatever they’ve settled on will always sound best to their ears.

A good way to do this is to pick a dynamic scene in a movie (lots of different sounds across the spectrum going on) and watch it several different times, switching between the different formats and listening for the differences. A specific sample like that will allow you to pick out what might otherwise have been subtle differences you’d have otherwise missed between the formats, but it should give you an idea of the tendencies of each format with regards to your equipment and listening environment (yep, even that can matter).

Hopefully this helps; best of luck :wink:


#5

See? That’s the wall of text I was expecting—well-rested even.


#6

In my defense, it was a complicated question.