Do I really need a DAC ? - AVS Forum
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post #1 of 18 Old 10-31-2012, 12:51 PM - Thread Starter
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Hi guys, new here and for sure not an audio pro but have a nice home theater and home audio system that I need some help with. Recently I installed some BW 7.4s (wanted 7.3s but pricey!!) and streaming Rhapsody through my Control4 controller to a Control4 whole home 8 channel amp and then out to the BWs. My issue is that the audio sounds flat, tinny and void of personality. I've been reading up on DAC but not sure if this is what I need to deliver better sound quality to the whole home system.

I'm looking at the PS Audio's products, Joletta, and a couple others. But gotta admit that this is an area that I have no idea what to do. Don't really want to spend 4k on a DAC., and concerned about spending a few hundred on some of the lower end system and end up with mediocre results.

All comments and help is appreciated.

Thanks !

Phil.
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post #2 of 18 Old 10-31-2012, 01:23 PM
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Unless something is horribly wrong with your existing equipment a DAC is the last thing likely to make a difference. Plug a CD player or something like that in and see if there appears to be a significant difference in the sound . . .

The technical differences between DAC chips are generally said to be inaudible these days, and AFAIK the supporting analog circuitry is well understood and should not be difficult for competent designers to get right.
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post #3 of 18 Old 10-31-2012, 03:56 PM - Thread Starter
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I though Rhapsody and other digital stream will all sound vacant when playing over a home audio system and is why we need to "condition" the audio first ? I'm no expert but can certainly hear the difference between a CD (already did this test) and internet radio.

Thanks!
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post #4 of 18 Old 10-31-2012, 04:10 PM
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You problem are the B&W speakers. They have little to no bass. Put the money toward a subwoofer (in-wall or stand-alone), hopefully with an EQ behind it. It is just the nature of that class of in-wall to not have much low-end. That should take away the tinniness. I suspect those being in-walls, you are not sitting with them directed at you. This means that you are not listening to the direct sound which is the best the speaker can do.

So no, I would not spend a penny on DACs in this case. You have a speaker+acoustic problem right now.
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post #5 of 18 Old 10-31-2012, 08:05 PM
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Rhapsody, if I'm not mistaken, is similar to Pandora, and is basically playing the equivalent of "lossy" MP3, a compressed format, where most of the original musical information is, believe it or not, thrown out... (and I love Pandora). Try something like www.hdtracks.com. You can download a few free High Rez songs to sample what a master recording sounds like. There are a few other sites that offer the same high rez music. Perhaps then you could purchase a separate DAC to do the duties that your current equipment may not be doing a good job of. But I would also ask, do the B&W's ever sound good? ...like what happens when you pop in a good CD or Blu-Ray?

What you are describing sounds like you are one of a small group of listeners who are demanding something better, where your average listener is perfectly happy with the compressed, lower quality MP3...lossy format.

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post #6 of 18 Old 10-31-2012, 08:12 PM
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You really can't make a "lossy" format sound any better, because as much as 90% of the original musical info was discarded...sad...and you can't get it back.

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post #7 of 18 Old 10-31-2012, 09:19 PM
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Agree with above two posts. A dac isn't going to help. And God knows, please don't buy new speakers based on glossy internet radio.

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post #8 of 18 Old 10-31-2012, 09:20 PM
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Glossy... lol. smile.gif

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post #9 of 18 Old 11-01-2012, 06:02 AM
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Quote:
Originally Posted by philom5 View Post

I though Rhapsody and other digital stream will all sound vacant when playing over a home audio system and is why we need to "condition" the audio first ? I'm no expert but can certainly hear the difference between a CD (already did this test) and internet radio.

IMO internet radio as well as satellite radio is generally beneath the pale from a quality standpoint. The technology could sound good but the actual bitrates often just don't allow good SQ. However, you should be able to get their sonic muddle to have reasonably well-balanced bass, midrange and treble.

The usual inability of AVS posters to give a make and model that provides useful results with a search engine afflicts your post, so I can't comment there. But that is the probable cause. That and room acoustics.
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post #10 of 18 Old 11-01-2012, 06:51 AM
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Let us wait for the OP's response to "do the B&W's ever sound good?"

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post #11 of 18 Old 11-04-2012, 09:12 PM
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It's certainly not due to MP3 per se (and it is redundant to refer to "lossy" MP3 -- MP3s are always lossy). If encoded properly -- high average bitrate, good codec -- MP3s are *extremely* difficult to tell from lossless, for most listeners. Internet streamed audio, however, might be encoded at low bitrates (introducing more audible artifacts), might use lossy codecs other than MP3 (most of which are good nowadays, but without knowing which was used for sure, it's hard to say) and may be processed in other ways (dynamic range compression, for example). And then there's the possibility that the OPs speakers and room and listening position aren't interacting well acoustically.
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post #12 of 18 Old 11-05-2012, 05:02 AM
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He already alluded to large difference between internet radio and CD. This still seems the most likely explanation.

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post #13 of 18 Old 11-05-2012, 05:24 AM
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Quote:
Originally Posted by Bigus View Post

He already alluded to large difference between internet radio and CD. This still seems the most likely explanation.

The only Internet radio I heard so far that sounded decent was BBC Radio 3 HD stream. Everything else was poor even comparing with regular FM broadcast.
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post #14 of 18 Old 11-05-2012, 09:44 AM
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Quote:
Originally Posted by Espo77 View Post

You really can't make a "lossy" format sound any better, because as much as 90% of the original musical info was discarded...sad...and you can't get it back.

Not to pick nits, but 90% loss due to lossy compression doesn't sound all that bad if recent technology is used wisely.

Uncompressed CD audio has a bit rate of 1,411,200 bits per second (16 x 2 x 44,100 bps). A bit rate of 320,000 bps or 320 kbps is generally very good sounding, usually indistinguishable from the uncompressed original. That is the same as compression by a factor of 44.1 or compression to 0.2267 of the original or 22%. 160 kbps or 11% is somewhat easier to hear a difference with, but still not all that bad particularly if the type of compression is AAC or MP4 as opposed to MP3.

Unfortunately internet audio streaming often involves far lower bitrates than 160 kbps. For example BBC has 8 different bitrates that they use, depending. Their best HD video format is said to use 192 kbps and modern H.264 compression techniques which can sound very good at that high of a bitrate, and even somewhat slower.

When the audio bitrates get much below 96 kbps, it may not be pretty. HD FM audio hits the 96 kbps mark on a good day if only one program is being transmitted at a time, but if other services are being transmitted at the same time the bitrate for even the fastest subchannel may be 64 or 48k, and that's slicing it pretty thin.
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post #15 of 18 Old 11-05-2012, 03:59 PM
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Quote:
Originally Posted by Bigus View Post

He already alluded to large difference between internet radio and CD. This still seems the most likely explanation.

Yeah, but then we got two posts saying it's because MP3s are bad..

MP3s needn't sound bad. Internet radio needn't sound bad. And yeah, the OP implies that CDs sound good, so we can scratch bad acoustics as a cause. So that leaves low bitrate encoding, and/or bad encoder, and/or preprocessing done to the stream at the source (unless his player is also doing something to the stream).

Btw this site says Rhapsody streams are in RAX (Real Audio Protected) format and have lo-fi and hi-fi options. Maybe the OP needs to investigate further.

Music service/File type(s)/DRM/Download bit rate/Streaming bit rate
Rhapsody/RAX (Harmony)/Yes/192Kbps/160Kbps (hi-fi) 64Kbps (lo-fi)
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post #16 of 18 Old 11-05-2012, 05:29 PM
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So that leaves low bitrate encoding, and/or bad encoder, and/or preprocessing done to the stream at the source
Or subconscious listener bias. It's not always the cause, but it's always a possible cause.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #17 of 18 Old 11-06-2012, 05:27 AM
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Quote:
Originally Posted by mcnarus View Post

Quote:
So that leaves low bitrate encoding, and/or bad encoder, and/or preprocessing done to the stream at the source
Or subconscious listener bias. It's not always the cause, but it's always a possible cause.

That's all true, but most people don't do good comparisons on other grounds as well.

(1) Level match. You'd think that all encoders and decoders match levels internally, but there are no guarantees.

(2) Listen to the identical same music encoded by two different ways. And, compare the two files while they are in perfect synch with each other.

(3) And then of course the problem of sighted bias, as you mention.

I think that you'd be surprised how many people blow off the first two issues that I mention. If you don't all three just right, the chances of fooling yourself are extremely high. Its nearly certain that if you don't do all of these 3 things, you'll hear a difference and it will be likely as not due to the sloppy comparison, not differences related to the issues being investigated.

Properly comparing 2 different encoders takes a little work, but on balance its one of the easiest comparisons to get right.
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post #18 of 18 Old 11-06-2012, 06:43 AM
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I did a comparison between a very highly ranked DAC - the Benchmark DAC1 and a very cheap Philips DVD-player than I went out an bought just for the experiment. I used a very good, as transparent as possible, stereo setup and calibrated the output levels of the DAC to the DVD-player. I used the player as the transport, so there's theoretically some additional improvement possible to find on that side.

The first impression was one of dismay that a DAC that cost so much more didn't really make a big difference. Honestly, it took a few minutes to figure out what to listen for to find noticable difference, and still I'm sure it would have been quite risky to claim that I'd be able to be as certain in a blind test.

So will I still feel there are minor details to improve with a DAC, it's not very cost efficient. And this was an el-cheapo DVD-player... stepping up just a little higher and the would most likely be close to nothing. Picking a great player like an Oppo-95 and there's no differences left to be found. And if you do go for a cheaper source, there's probably a better DAC in the home theater receiver that can be used.

Spending the same amount of money on acoustics is MUCH better bang for the buck imho.

Under construction: the Larch theater
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