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Old 06-08-2010, 07:25 PM
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EnzoTen EnzoTen is offline
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Default Apt-X Wired Quality Over Bluetooth

I have been testing the Creative ZiiSound D5 and its turning out to be quite a nice sounding pair of speakers. It uses an audio codec that gets wrapped into Bluetooth A2DP called Apt-X. It offers CD quality bandwidth so it basically has the quality of a wired connection. Sennhieser uses it in their Bluetooth headphones, Shure uses it for live performance products, and it seems to be used in a lot of pro audio setups.

This is my first experience with this and am pretty impressed. Has anyone else had any experience with these Apt-X enabled products? Is this the sound quality jump that makes bluetooth legitimate?
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Old 06-08-2010, 08:39 PM
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WalkGood WalkGood is offline
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Members may want to read the Apt-X technology overview here, some interesting downloads for reading there along with some nice pics in the brochure download & more info. Very little quoted below but thought I'd give you an idea, they claim their advantage is low latency, full frequency bandwidth and no quality degradation when MP3 or AAC data is transcoded. Will be nice to hear your feedback on it Enzo …

Quote:
In the early 90’s APTX launched apt-X, a real-time digital audio data reduction system, that compresses 16-bit PCM audio samples by a factor of 4:1, with no perceptible audible degradation. In 1999 APTX released the Enhanced apt-X algorithm for applications demanding higher bit rate audio.

Apt-X is based on subband Adaptive Differential Pulse Code Modulation, (Subband ADPCM). CD and other high end digital audio systems use 16-bit linear pulse code modulation, (linear PCM). As it's name implies ADPCM is a technique which re-codes the difference between two digital audio samples, using quantisation step-sizes that adapt to the energy of the input audio signal. In this way ADPCM can provide a similar audio quality to linear PCM but at a much reduced bitrate.

apt-X system aims to transparently code 16-bit PCM audio with a fixed compression ratio of 4:1. Standard apt-X algorithm takes a series of 16 bit PCM words and passes these through a 2-stage QMF tree. Splitting the signal into 4 equally divided subbands according to frequency content. The QMF also down samples the clock rate to ¼ the incoming clock and produces 4 x 16 bit Frequency samples, which are then passed into four subband processing routines. ... ... ...
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Old 06-07-2011, 11:31 AM
Aaronio Aaronio is offline
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Quote:
Originally Posted by EnzoTen View Post
I have been testing the Creative ZiiSound D5 and its turning out to be quite a nice sounding pair of speakers. It uses an audio codec that gets wrapped into Bluetooth A2DP called Apt-X. It offers CD quality bandwidth so it basically has the quality of a wired connection. Sennhieser uses it in their Bluetooth headphones, Shure uses it for live performance products, and it seems to be used in a lot of pro audio setups.

This is my first experience with this and am pretty impressed. Has anyone else had any experience with these Apt-X enabled products? Is this the sound quality jump that makes bluetooth legitimate?
Hello EnzoTen, I am considering on buying this same speakers.

I just have a specific doubt, should I install the codec on the emitter unit (this case my HTC HD2) for this to work?

If not, does that mean every bluethoot device already sends full quality audio and the receivers are the ones that crop it?
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