Uh yes, most certainly I would, because otherwise engineers are going to wonder how the heck you're pushing the raw data across the link without losing fidelity.
This *preserves* the quality. Not their problem that some members of the public (who are not the targeted audience of that release) don't understand the technology.
Uh yes, most certainly I would, because otherwise engineers are going to wonder how the heck you're pushing the raw data across the link without losing fidelity.
This *preserves* the quality. Not their problem that some members of the public (who are not the targeted audience of that release) don't understand the technology.
If they say that it's lossless, that should be enough. People understand that.
...it seems ridiculous they would spend all that money developing for one particular model of mp3 player when they don't need to..."
I think it's great when devices are made that are "iPod-only" because it strengthens the iPod, which is good for Apple and good for consumers because a strong iPod business allows accessories to be standardized around them making it safer for companies to innovate, and ultimatley gives consumers more to choose from. Apple's predictable iPod release cycles and market strength actually attract third parties by making it possible for accesory manufacturers to be innovative and still manage thier inventory successfully by avoiding excess inventory (to a degree.)
So if someone wants to sell an "iPod-only" accessory that's OK with me.
If they say that it's lossless, that should be enough. People understand that.
Yeah, but engineers know that 4:1 adacp is lossless, and engineers are the ones buying the asics. The article from AI goes much further than any documentaion available from Aura's site. The advertised 410kbps stream should be enough to provide lossless, CD quality sound if they use a 4:1 compression, with some extra room in the bandwith as well. That's enough information to let the integrator know exactly what the asic is meant to be capable of.
Yeah, but engineers know that 4:1 adacp is lossless, and engineers are the ones buying the asics. The article from AI goes much further than any documentaion available from Aura's site. The advertised 410kbps stream should be enough to provide lossless, CD quality sound if they use a 4:1 compression, with some extra room in the bandwith as well. That's enough information to let the integrator know exactly what the asic is meant to be capable of.
I haven't looked at the site.
But, 4:1 should do it, though that's a bit high for lossless in general. It would have to be a very good algorithm.
But, 4:1 should do it, though that's a bit high for lossless in general. It would have to be a very good algorithm.
Wow, this is getting technical.
For most material the Microsoft ADPCM algorithm is the equivalent of AIFF. But compounding compression (say AAC with ADPCM) could ring out a few artifacts which the casual listener is not going to notice.
I listened to a Creative prototype using the Aura LibertyLink chip last year at CES. The audio quality is more than suitable for "portable applications". Of course the compression algorithm must be up to par... but voicing the headphone speakers is probably going to be more important. Most interesting is that on the CES floor, where there are hundreds of interferers (BlueTooth, WiFi, etc) there were no dropouts in the audio.
Anyway, the bigger question... is it worth the money to cut the wire?
For most material the Microsoft ADPCM algorithm is the equivalent of AIFF. But compounding compression (say AAC with ADPCM) could ring out a few artifacts which the casual listener is not going to notice.
I listened to a Creative prototype using the Aura LibertyLink chip last year at CES. The audio quality is more than suitable for "portable applications". Of course the compression algorithm must be up to par... but voicing the headphone speakers is probably going to be more important. Most interesting is that on the CES floor, where there are hundreds of interferers (BlueTooth, WiFi, etc) there were no dropouts in the audio.
Anyway, the bigger question... is it worth the money to cut the wire?
AIFF is not a compressed signal though. That's straight off a CD, which is not compressed.
But you can't use two compression algorithms at once in any effective way. A fully compressed signal is already at the lowest information state it can be in for that purpose. One algorithm can be somewhat more effective than another, but to apply one over the other is not good practice, or very useful.
Try to Zip a file, and then use Stuffit. You will see what I mean.
Manufacturers don't "voice" headphones the way some small hi end companies do speaker systems.
That's because zip and stuffit are relatively close in max entropy levels.
Yes. That was the point I made about the lowest information state. It's exactly the same thing, assuming a perfect algorithm. That's why there is no point to using two algorithm's. If one is lossless, that's the best that can be done. Any minor gain by using another, different one, after that, that might be realised, would not be worth the extra computation time.
Manufacturers don't "voice" headphones the way some small hi end companies do speaker systems. [/B][/QUOTE]
Low end headphones are not voiced, but the speaker driver is matched to the cavity.
For medium end headphones the vent tape on the back of the driver is changed to give a response best suited for the cavity. You can make a tinny or boomy headphone by playing with the vent tape, the cavity and the venting.
iPod earbuds, made by Foster, get extra bass response having the longer tube extending over the wire.
Unless I'm *completely* misinterpreting the scheme, ADPCM isn't being applied to a compressed format at all, but the decompressed audio signal.
cf Apple Lossless and AirPort Extreme.
I see it as:
AAC (or MP3) from iPod to iPod DAC to 3.5mm audio jack to input of LibertyLink
LibertyLink compresses 4:1 ADPCM and transmits over the link.
Headphone LibertyLink chip receives the transmitted ADPCM, decompresses, sends to headphone DAC and through to speakers.
I've read past papers on LibertyLink. The transmission scheme is GMSK but that would have nothing to do with the audio.
Paper mentions a "back channel" which is transmitted from the headphone back to the base unit. It's for power control, bit error checking, and offers the possibility for the headphone to control the player in future implementations. If that is used via the iPod OmniConnector then "made for iPod" license will have to be paid.
Manufacturers don't "voice" headphones the way some small hi end companies do speaker systems.
Low end headphones are not voiced, but the speaker driver is matched to the cavity.
For medium end headphones the vent tape on the back of the driver is changed to give a response best suited for the cavity. You can make a tinny or boomy headphone by playing with the vent tape, the cavity and the venting.
iPod earbuds, made by Foster, get extra bass response having the longer tube extending over the wire. [/B][/QUOTE]
I should go and tell Grado and Sennheiser about that. Neither do that. I mention them. because I've worked with both in the past. Joe was, for many years, until he passed away, a friend of mine.
Matching a driver and case isn't "voicing". We do that by formula. The same way we design free standing speakers. The only difference is that we need to use formulas that simulate the ear cavity as well, instead of calculating total power into a room.
Voicing is listening to a design late in the design process and then doing final tuning and changes to the design, by ear. The designer does that. A very few designs may allow you to "Tune" for your preferred balance, but that is not voicing.
Yes. That was the point I made about the lowest information state. It's exactly the same thing, assuming a perfect algorithm. That's why there is no point to using two algorithm's.
Well, JPEG is actually an assortment of lossless algorithms along with a lossy one. If I remember correctly, JPEG uses both Huffmann encoding and RLE. But I understand what you mean. In any case, this 4:1 alg that's the topic here is done on the decompressed AAC/MP3 audio signal.
Well, JPEG is actually an assortment of lossless algorithms along with a lossy one. If I remember correctly, JPEG uses both Huffmann encoding and RLE. But I understand what you mean. In any case, this 4:1 alg that's the topic here is done on the decompressed AAC/MP3 audio signal.
That's correct. I was responding to a post that, I believe, was suggesting that two separate compression schemes were being used.
As the back plate of most iPods is some alloy of SS, that itself could cause a problem. But I don't know which alloy it is, 200, 300, or 400 series. That could make a big difference.
Is it really stainless steel? It's so rediculously soft that I assumed it was aluminum. Some other people said it was aluminum as well, but I've never gotten corroboration. Whatever it is, the alloy choice was bad, IMO.
Comments
Compression rate has nothing to do with the final result in a lossless algorithm.
This *preserves* the quality. Not their problem that some members of the public (who are not the targeted audience of that release) don't understand the technology.
Originally posted by Kickaha
Uh yes, most certainly I would, because otherwise engineers are going to wonder how the heck you're pushing the raw data across the link without losing fidelity.
This *preserves* the quality. Not their problem that some members of the public (who are not the targeted audience of that release) don't understand the technology.
If they say that it's lossless, that should be enough. People understand that.
Originally posted by dak splunder
...it seems ridiculous they would spend all that money developing for one particular model of mp3 player when they don't need to..."
I think it's great when devices are made that are "iPod-only" because it strengthens the iPod, which is good for Apple and good for consumers because a strong iPod business allows accessories to be standardized around them making it safer for companies to innovate, and ultimatley gives consumers more to choose from. Apple's predictable iPod release cycles and market strength actually attract third parties by making it possible for accesory manufacturers to be innovative and still manage thier inventory successfully by avoiding excess inventory (to a degree.)
So if someone wants to sell an "iPod-only" accessory that's OK with me.
Originally posted by melgross
If they say that it's lossless, that should be enough. People understand that.
Yeah, but engineers know that 4:1 adacp is lossless, and engineers are the ones buying the asics. The article from AI goes much further than any documentaion available from Aura's site. The advertised 410kbps stream should be enough to provide lossless, CD quality sound if they use a 4:1 compression, with some extra room in the bandwith as well. That's enough information to let the integrator know exactly what the asic is meant to be capable of.
Originally posted by Splinemodel
Yeah, but engineers know that 4:1 adacp is lossless, and engineers are the ones buying the asics. The article from AI goes much further than any documentaion available from Aura's site. The advertised 410kbps stream should be enough to provide lossless, CD quality sound if they use a 4:1 compression, with some extra room in the bandwith as well. That's enough information to let the integrator know exactly what the asic is meant to be capable of.
I haven't looked at the site.
But, 4:1 should do it, though that's a bit high for lossless in general. It would have to be a very good algorithm.
Originally posted by melgross
I haven't looked at the site.
But, 4:1 should do it, though that's a bit high for lossless in general. It would have to be a very good algorithm.
Wow, this is getting technical.
For most material the Microsoft ADPCM algorithm is the equivalent of AIFF. But compounding compression (say AAC with ADPCM) could ring out a few artifacts which the casual listener is not going to notice.
I listened to a Creative prototype using the Aura LibertyLink chip last year at CES. The audio quality is more than suitable for "portable applications". Of course the compression algorithm must be up to par... but voicing the headphone speakers is probably going to be more important. Most interesting is that on the CES floor, where there are hundreds of interferers (BlueTooth, WiFi, etc) there were no dropouts in the audio.
Anyway, the bigger question... is it worth the money to cut the wire?
Originally posted by Trendannoyer
if this is avalible NOW why is it on the FUTURE HARDWARE thread?
Near future?
Audition product is available next month. From the write-up it looks like other LibertyLink based accessories will come out in coming months.
Originally posted by podlife
Wow, this is getting technical.
For most material the Microsoft ADPCM algorithm is the equivalent of AIFF. But compounding compression (say AAC with ADPCM) could ring out a few artifacts which the casual listener is not going to notice.
I listened to a Creative prototype using the Aura LibertyLink chip last year at CES. The audio quality is more than suitable for "portable applications". Of course the compression algorithm must be up to par... but voicing the headphone speakers is probably going to be more important. Most interesting is that on the CES floor, where there are hundreds of interferers (BlueTooth, WiFi, etc) there were no dropouts in the audio.
Anyway, the bigger question... is it worth the money to cut the wire?
AIFF is not a compressed signal though. That's straight off a CD, which is not compressed.
But you can't use two compression algorithms at once in any effective way. A fully compressed signal is already at the lowest information state it can be in for that purpose. One algorithm can be somewhat more effective than another, but to apply one over the other is not good practice, or very useful.
Try to Zip a file, and then use Stuffit. You will see what I mean.
Manufacturers don't "voice" headphones the way some small hi end companies do speaker systems.
AAC -> audio -> headphone jack -> wire -> headphones, right?
AAC -> audio -> headphone jack -> Aura box -> ADPCM -> wireless -> headphones
Unless I'm *completely* misinterpreting the scheme, ADPCM isn't being applied to a compressed format at all, but the decompressed audio signal.
cf Apple Lossless and AirPort Extreme.
Originally posted by melgross
Try to Zip a file, and then use Stuffit. You will see what I mean.
That's because zip and stuffit are relatively close in max entropy levels.
Originally posted by Splinemodel
That's because zip and stuffit are relatively close in max entropy levels.
Yes. That was the point I made about the lowest information state. It's exactly the same thing, assuming a perfect algorithm. That's why there is no point to using two algorithm's. If one is lossless, that's the best that can be done. Any minor gain by using another, different one, after that, that might be realised, would not be worth the extra computation time.
Low end headphones are not voiced, but the speaker driver is matched to the cavity.
For medium end headphones the vent tape on the back of the driver is changed to give a response best suited for the cavity. You can make a tinny or boomy headphone by playing with the vent tape, the cavity and the venting.
iPod earbuds, made by Foster, get extra bass response having the longer tube extending over the wire.
Originally posted by Kickaha
Hurm.
AAC -> audio -> headphone jack -> wire -> headphones, right?
AAC -> audio -> headphone jack -> Aura box -> ADPCM -> wireless -> headphones
Unless I'm *completely* misinterpreting the scheme, ADPCM isn't being applied to a compressed format at all, but the decompressed audio signal.
cf Apple Lossless and AirPort Extreme.
I see it as:
AAC (or MP3) from iPod to iPod DAC to 3.5mm audio jack to input of LibertyLink
LibertyLink compresses 4:1 ADPCM and transmits over the link.
Headphone LibertyLink chip receives the transmitted ADPCM, decompresses, sends to headphone DAC and through to speakers.
I've read past papers on LibertyLink. The transmission scheme is GMSK but that would have nothing to do with the audio.
Paper mentions a "back channel" which is transmitted from the headphone back to the base unit. It's for power control, bit error checking, and offers the possibility for the headphone to control the player in future implementations. If that is used via the iPod OmniConnector then "made for iPod" license will have to be paid.
Originally posted by podlife
Manufacturers don't "voice" headphones the way some small hi end companies do speaker systems.
Low end headphones are not voiced, but the speaker driver is matched to the cavity.
For medium end headphones the vent tape on the back of the driver is changed to give a response best suited for the cavity. You can make a tinny or boomy headphone by playing with the vent tape, the cavity and the venting.
iPod earbuds, made by Foster, get extra bass response having the longer tube extending over the wire. [/B][/QUOTE]
I should go and tell Grado and Sennheiser about that. Neither do that. I mention them. because I've worked with both in the past. Joe was, for many years, until he passed away, a friend of mine.
Matching a driver and case isn't "voicing". We do that by formula. The same way we design free standing speakers. The only difference is that we need to use formulas that simulate the ear cavity as well, instead of calculating total power into a room.
Voicing is listening to a design late in the design process and then doing final tuning and changes to the design, by ear. The designer does that. A very few designs may allow you to "Tune" for your preferred balance, but that is not voicing.
Originally posted by melgross
Yes. That was the point I made about the lowest information state. It's exactly the same thing, assuming a perfect algorithm. That's why there is no point to using two algorithm's.
Well, JPEG is actually an assortment of lossless algorithms along with a lossy one. If I remember correctly, JPEG uses both Huffmann encoding and RLE. But I understand what you mean. In any case, this 4:1 alg that's the topic here is done on the decompressed AAC/MP3 audio signal.
Originally posted by Splinemodel
Well, JPEG is actually an assortment of lossless algorithms along with a lossy one. If I remember correctly, JPEG uses both Huffmann encoding and RLE. But I understand what you mean. In any case, this 4:1 alg that's the topic here is done on the decompressed AAC/MP3 audio signal.
That's correct. I was responding to a post that, I believe, was suggesting that two separate compression schemes were being used.
Originally posted by melgross
As the back plate of most iPods is some alloy of SS, that itself could cause a problem. But I don't know which alloy it is, 200, 300, or 400 series. That could make a big difference.
Is it really stainless steel? It's so rediculously soft that I assumed it was aluminum. Some other people said it was aluminum as well, but I've never gotten corroboration. Whatever it is, the alloy choice was bad, IMO.