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Raspberry Pi gets its own sound card

engadget.com

11–20 of 33 posts

Re: Raspberry Pi gets its own sound card

#11
post #9

What bus is used to communicate with the sound card? The obvious candidate is USB, but the Pi's USB bandwidth is limited and I don't recall whether USB is available on the pin headers.

If it uses the P5 header, then it's I2C - so there are no USB issues. I remember reading about (other?) Wolfson DACs on Raspi and they were using I2C.

Re: Raspberry Pi gets its own sound card

#12
post #2

I love the fact that a whole ecosystem has appeared around patching up the holes in the Pi's architecture[1]. Unfortunately by the time you've purchased them all, you probably could have bought a BeagleBoard instead. [1] The built in codec and filtering is absolutely horrible making it pretty useless for audio applications.

usually when people do [1] or something like that it's to a link. to my ear the audio out of the pi's hdmi port is perfectly fine. i think the DAC used in the RCA jack is probably not very good. I would pay for a HDMI audio to DAC adapter rather than $33 for another soundcard that just works with the pi.

usually when people do [1] or something like that it's to a link

Offtopic, but footnotes predate the web by quite some time. If only we had a easy way of formatting super/subscript...

Re: Raspberry Pi gets its own sound card

#13
post #2

I love the fact that a whole ecosystem has appeared around patching up the holes in the Pi's architecture[1]. Unfortunately by the time you've purchased them all, you probably could have bought a BeagleBoard instead. [1] The built in codec and filtering is absolutely horrible making it pretty useless for audio applications.

If you using it for HTPC then beagleboard is useless as it has no hardware based video decoding. That is why the Pi is so popular for HTPC's, built in H264 decoding hardware

Re: Raspberry Pi gets its own sound card

#14
post #6

Nice. PI's built in audio processing is extremely crappy and the analog 3.5mm output is almost unusable for music.

How can I actually hear this? I am no audiophile, but I can't notice any audio problems with my Pi.

I find quality in-ear headphones extremely revealing of poor quality output. Shure e5c, to pick an older set that I own, are especially unforgiving of noisy output stages and cross-coupled interference. The additional acoustic isolation really helps your brain focus on the audio by cutting out the masking effects of environmental noise. This isn't always a good thing.

For example, the Cowon S9 audio player was supposedly designed for high output quality, with a pile of DSP presets for EQ etc. With the e5c's you can really hear the poor quality processing of the EQ, especially on reverb tails. Have to turn the EQ off completely to eliminate them.

Re: Raspberry Pi gets its own sound card

#15
post #6

Earlier quoted context omitted.

How can I actually hear this? I am no audiophile, but I can't notice any audio problems with my Pi.

apparently the DAC for the RCA out is 11bit - but I can't really find any definitive proof of that.

That should be pretty easy to demonstrate by feeding the output back into a decent 16-bit soundcard - the noise floor should reveal any dithering going on (and if there's no dithering it will be painfully obvious that there's only 2048 discrete output values...)

I might have a go tonight.

Re: Raspberry Pi gets its own sound card

#16
post #4

Link: http://uk.farnell.com/wolfson-microelectronics/wolfson-audio... It's disappointing that this doesn't support v1.0 boards. I hadn't realised that RPis had been fragmented like that.

It looks like the P5 header that it uses was only added in rev2, and "intended to be a suitable attachment point for ... audio codec boards"[1].

It's definitely a shame that things are fragmented, I was considering adding audio to my old Pi. But at least they're cheap enough to justify buying a second one :-)

[1] http://www.raspberrypi.org/archives/1929

Re: Raspberry Pi gets its own sound card

#17
post #14
post #6

Earlier quoted context omitted.

How can I actually hear this? I am no audiophile, but I can't notice any audio problems with my Pi.

I find quality in-ear headphones extremely revealing of poor quality output. Shure e5c, to pick an older set that I own, are especially unforgiving of noisy output stages and cross-coupled interference. The additional acoustic isolation really helps your brain focus on the audio by cutting out the masking effects of environmental noise. This isn't always a good thing. For example, the Cowon S9 audio player was suppos…

By EQ you are referring to equalizer? So if I don't use EQ on RPi (which I don't), I'm good? Is there some particular audio clip which I can sense the crappiness when listening to?

Re: Raspberry Pi gets its own sound card

#18
post #6

Earlier quoted context omitted.

How can I actually hear this? I am no audiophile, but I can't notice any audio problems with my Pi.

apparently the DAC for the RCA out is 11bit - but I can't really find any definitive proof of that.

RCA? Isn't the RCA output for video only? I was referring to 3.5mm green audio output.

Re: Raspberry Pi gets its own sound card

#19
post #17
post #14

Earlier quoted context omitted.

I find quality in-ear headphones extremely revealing of poor quality output. Shure e5c, to pick an older set that I own, are especially unforgiving of noisy output stages and cross-coupled interference. The additional acoustic isolation really helps your brain focus on the audio by cutting out the masking effects of environmental noise. This isn't always a good thing. For example, the Cowon S9 audio player was suppos…

By EQ you are referring to equalizer? So if I don't use EQ on RPi (which I don't), I'm good? Is there some particular audio clip which I can sense the crappiness when listening to?

I was talking about a specific hardware player, but in general any additional signal processing has the potential to add artefacts.

To hear these sorts of things, listen for reverb tails on drum hits, high frequency percussion like cymbals, high-hats, solo human voice (we're quite good at hearing unnatural artefacts in voices) - that sort of thing. Beware it has to be good quality source material to start with though!

Re: Raspberry Pi gets its own sound card

#20
post #12

Earlier quoted context omitted.

usually when people do [1] or something like that it's to a link. to my ear the audio out of the pi's hdmi port is perfectly fine. i think the DAC used in the RCA jack is probably not very good. I would pay for a HDMI audio to DAC adapter rather than $33 for another soundcard that just works with the pi.

usually when people do [1] or something like that it's to a link Offtopic, but footnotes predate the web by quite some time. If only we had a easy way of formatting super/subscript...

No need for formatting; you can easily get superscripts and subscripts in plain text. See Unicode’s Superscripts and Subscripts Block¹.

――――――

¹ — https://en.wikipedia.org/wiki/Unicode_subscripts_and_supersc...

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