[x RELIC x]

In the end, it is how the manufacturer makes due with the components manufacturer.
so far, and seeing Apple vs Qualcomm lawsuit, it seems it is a bundle package deal, whether one would use the function or not.

The only reason I'm replying is that the idea of using a DAC in the CPU (which Rockchip specifications don't specify anywhere) for Bluetooth is misinformation. There is no DAC used to send a digital Bluetooth signal, ever, in any device. It can't be done because Bluetooth is a digital transmission and can't use a DAC before the signal is sent. It's not a matter of what a manufacturer decides to use.

 

[esprithk]

First I don't appreciate the tone. Period.

Second, to transmit a digital signal it must remain a digital signal. Yes, it bypasses the internal DAC because the digital bitstream is not converted to analogue before it is sent over Bluetooth, but a Bluetooth signal does not use a DAC built in to the CPU. The SoC simply decodes the file format to a digital bitstream to pass along to the DAC in the receiving Bluetooth device. This is absolutely not the same as Digital to Analogue conversion.

Good luck finding any portable audio device that transmits an analogue signal over a Bluetooth connection.

Edit: Decoding a file format is not the same as converting to analogue and this may be where the confusion comes up time and time again. Both are needed to read digital files and to hear them through our transducers.

Thank you for the clarification.
Yes, you are right about digital signal to bluetooth.

So, with aptX (not much about aptX HD yet),

Please correct me if I am wrong,

First, it seems there are certain bundle package and agreement between DAP manufacturers (including smartphones) and the component suppliers.

With the bundle packing (CPU + CPU's DAC + Bluetooth chipset) , it would come to the following results:

During bluetooth process,
(1) Route 1

Snapdragon 8XX CPU ==> Audio files => audio digital signal to "CPU's DAC ==> analogue (headphone).
*DAPs manufacture can bypass this feature and use a 3rd party DAC.


(2) Route 2 => Snapdragon 8XX CPU ==> ==> Audio files ==> audio digital signal to CPU's DAC but is not fully processed and being sent to the bluetooth chipset for further processing".
*This part really depends on the CPU manufacturer if it is allowed the bluetooth chipset to work with other 3rd party DAC.

Now the real question that needs the answer.

(a) it may charge a premium to release the feature of supporting 3rd part DAC.
(b) It just does not sell this feature at all even it is available.
(c) aptX codec only works with the CPU's built in DAC?

 

[esprithk]

The only reason I'm replying is that the idea of using a DAC in the CPU (which Rockchip specifications don't specify anywhere) for Bluetooth is misinformation. There is no DAC used to send a digital Bluetooth signal, ever, in any device. It can't be done because Bluetooth is a digital transmission and can't use a DAC before the signal is sent. It's not a matter of what a manufacturer decides to use.

yes, I understand what you are saying. so it is up to the Snapdragon CPU to process the digital signal to
(1) DAC
(2) Bluetooth chipset.

so, the real question, is the support for 3rd party DAC is available in the business deals between components suppliers and DAP/smartphone manufacturers?

the answers we need:
(a) it may charge a premium to release the feature of supporting 3rd part DAC.
(b) It just does not sell this feature at all even it is available. (see penalty from EU to Qualcomm due to monopoly of market, same also China government issue penalty on Qualcomm)
(c) aptX codec only works with the CPU's built in DAC? *I think the audio signal has to pass through the DAC first, but is not fully processed and sent to bluetooth chipset.

 

[Brooko]

I think it might be the case of errors in the terminology used Craig - I can understand what he's meaning, and may have just confused the two.

With Bluetooth (in very simple language), the two devices have to be able to share common profiles and codecs in order to operate. Most popular profile for audio at the moment is A2DP (Advanced Audio Distribution profile). Within the profile there are a variety of codecs - including SBC (low level and most common minimum), aac and aptx. Each has different bandwidth limits.

So assuming I have an iPhone and good Bluetooth compatible headphone (I have an iPhone SE and FiiL Diva - the combo is excellent) - then the two devices will use the A2DP profile with the aac codec. If I have MP3 files, they will be digitally converted to aac "on the fly" and transmitted to the headphones. The headphones will then convert that signal to analogue. But if I am using aac - there is no digital conversion before transmission to the Bluetooth headset.

If I'm using the X7 and both devices support aptx (and I'm playing FLAC files), there is still digitial conversion (and potentially some compression). AptX uses ADPCM - so the FLAC file is converted sent ot the Bluetooth headphone/speaker, and then decoded by the DAC in the headphones - to analogue.

So there is digital conversion at the source - into a codec that both devices can transmit/receive. But Craig is right - the actual analogue conversion occurs at the headphones.

Now the interesting thing is that for Apple users, using aptX (I know they can't use aptX from Apple devices) would conceivably be worse than using the native aac that is currently used. The reason is that for their aac files, there is no digital conversion - they can be transmitted "as-is".

I've tried both aac and aptX enabled devices - and I can't really tell any difference. To me the pre-requisites are that the recording is good, the hardware works well, and that the Bluetooth signal is strong enough to hold without dropouts. The X7 actually handles Bluetooth pretty well. But as far as signal strength goes, my iPhone still does a better job. Of course that all changes when switching to a wired connection

 

[esprithk]

The only reason I'm replying is that the idea of using a DAC in the CPU (which Rockchip specifications don't specify anywhere) for Bluetooth is misinformation. There is no DAC used to send a digital Bluetooth signal, ever, in any device. It can't be done because Bluetooth is a digital transmission and can't use a DAC before the signal is sent. It's not a matter of what a manufacturer decides to use.

from the news in smartphone so far, many manufacturers turn to Qualcomm bundle because of the very competitive price.
But with the penalty order by EU and China, it seems there are restriction on how to use them.

 

[x RELIC x]

@esprithk, you are completely missing the point. There is no DAC (DIGITAL to ANALOGUE CONVERTER) in the transmission of Bluetooth. The source CPU would not use any built in DAC to send a Bluetooth signal (also, show me a specification sheet on any built in CPU DAC in the Rockchip 3188 SoC - I haven't seen any, anywhere).

If the signal was using the DAC in the sending device (which it wouldn't) it would be sending an analogue signal which it doesn't and can't. That's why we sample analogue to digital in the first place, so it's easier to manipulate. The bandwidth required to send an analogue audio signal would be too large for the portable electronics to handle computationally (essentially an analogue signal is continuous data, also know as infinite sampling - Digital is defined as sampled data, which is easier to work with).

In the receiving device the Bluetooth receiver would take the digital signal and send it to the DAC in the receiving device. So, any Bluetooth headphones one may use actually have a DAC/amp built in (that's why they need a power source).

 

[esprithk]

I think it might be the case of errors in the terminology used Craig - I can understand what he's meaning, and may have just confused the two.

With Bluetooth (in very simple language), the two devices have to be able to share common profiles and codecs in order to operate. Most popular profile for audio at the moment is A2DP (Advanced Audio Distribution profile). Within the profile there are a variety of codecs - including SBC (low level and most common minimum), aac and aptx. Each has different bandwidth limits.

So assuming I have an iPhone and good Bluetooth compatible headphone (I have an iPhone SE and FiiL Diva - the combo is excellent) - then the two devices will use the A2DP profile with the aac codec. If I have MP3 files, they will be digitally converted to aac "on the fly" and transmitted to the headphones. The headphones will then convert that signal to analogue.

If I'm using the X7 and both devices support aptx (and I'm playing FLAC files), there is still conversion (and some compression). AptX uses ADPCM - so the FLAC file is converted sent, and then decoded by the DAC in the headphones - to analogue.

So there is digital conversion at the source - into a codec that both devices can transmit/receive. But Craig is right - the actual analogue conversion occurs at the headphones.

Now the interesting thing is that for Apple users, using aptX (I know they can't use aptX from Apple devices) would conceivably be worse than using the native aac that is currently used. The reason is that for their aac files, there is no digital conversion - they can be transmitted "as-is".

I've tried both aac and aptX enabled devices - and I can't really tell any difference. To em the pre-requisites are that the recording is good, the hardware works well, and that the Bluetooth signal is strong enough to hold without dropouts. The X7 actually handles Bluetooth pretty well. But as far as signal strength goes, my iPhone still does a better job. Of course that all changes when switching to a wired connection

I think with the coming Android o + LDAC chipset, it will force aptX / aptX HD to free up the bundle restriction.
Actually, everyone should just hold on till 2018 to see more information.

Now the users just go crazy on all the marketing noise about aptX / aptX HD now.
But many don't read finance news about the strings they pull behind the curtain.

Unless a DAP brand is so proud to announce their bluetooth transmission by done with a 3rd party DAC, I keep my doubt on the whole thing.
*Remark: I just use SONY products for bluetooth listening at the moment. and waiting for Apple iPhone 10th anniversary to have good news about upgrades on audio quality.

Even for iPhone, I use SONY MDR-1ADAC headphone or lightening to LG HiFi Plus B&O module to headphone.

 

[esprithk]

@esprithk, you are completely missing the point. There is no DAC (DIGITAL to ANALOGUE CONVERTER) in the transmission of Bluetooth. The source CPU would not use any built in DAC to send a Bluetooth signal (also, show me a specification sheet on any built in CPU DAC in the Rockchip 3188 SoC - I haven't seen any, anywhere).

If the signal was using the DAC in the sending device (which it wouldn't) it would be sending an analogue signal which it doesn't and can't. That's why we sample analogue to digital in the first place, so it's easier to manipulate. The bandwidth required to send an analogue audio signal would be too large for the portable electronics to handle computationally (essentially an analogue signal is continuous data, also know as infinite sampling - Digital is defined as sampled data, which is easier to work with).

In the receiving device the Bluetooth receiver would take the digital signal and send it to the DAC in the receiving device. So, any Bluetooth headphones one may use actually have a DAC/amp built in (that's why they need a power source).

OK, Thx. You are absolutely correct.

So all this hype about aptX support is actually using Qualcomm chipset for decode (in the receiving end *the bluetooth headphones or speakers?).

Regardless what DAC (single, dual, or quad DACs) in the smartphones or DACs, when it uses aptX BT, it is just using Qualcomm chipset in bluetooh headphones/speakers. Right?


So, updated my route.

With Bluetooth aptX/ aptX HD,

Snapdragon CPU ==> audio file ==> aptx bluetooth chipset (obviously by Qualcomm) ===//===="Bluetooth headphone with aptx decode chipset (obviously by Qualcomm) and has a power source.

Thx.


So, this actually makes me happy that I use SONY products for bluetooth listening.

 

[x RELIC x]

I think it might be the case of errors in the terminology used Craig - I can understand what he's meaning, and may have just confused the two.

With Bluetooth (in very simple language), the two devices have to be able to share common profiles and codecs in order to operate. Most popular profile for audio at the moment is A2DP (Advanced Audio Distribution profile). Within the profile there are a variety of codecs - including SBC (low level and most common minimum), aac and aptx. Each has different bandwidth limits.

So assuming I have an iPhone and good Bluetooth compatible headphone (I have an iPhone SE and FiiL Diva - the combo is excellent) - then the two devices will use the A2DP profile with the aac codec. If I have MP3 files, they will be digitally converted to aac "on the fly" and transmitted to the headphones. The headphones will then convert that signal to analogue.

If I'm using the X7 and both devices support aptx (and I'm playing FLAC files), there is still conversion (and some compression). AptX uses ADPCM - so the FLAC file is converted sent, and then decoded by the DAC in the headphones - to analogue.

So there is digital conversion at the source - into a codec that both devices can transmit/receive. But Craig is right - the actual analogue conversion occurs at the headphones.

Now the interesting thing is that for Apple users, using aptX (I know they can't use aptX from Apple devices) would conceivably be worse than using the native aac that is currently used. The reason is that for their aac files, there is no digital conversion - they can be transmitted "as-is".

I've tried both aac and aptX enabled devices - and I can't really tell any difference. To em the pre-requisites are that the recording is good, the hardware works well, and that the Bluetooth signal is strong enough to hold without dropouts. The X7 actually handles Bluetooth pretty well. But as far as signal strength goes, my iPhone still does a better job. Of course that all changes when switching to a wired connection

As I've said Paul, converting file formats to a digital codec for Bluetooth is not using a DAC at all. This is all I'm pointing out as the signal remains in the digital realm until the receiving device sends the signal to the DAC on the receiving end. In the end the Bluetooth signal that is sent never goes through any DAC before it is sent. I commented because this is a gross misrepresentation of how Bluetooth works so I thought I'd help clarify.

 

[x RELIC x]

OK, Thx.
So you are saying all this hype about aptX support is actually using Qualcomm chipset for decode (in the receiving end *the bluetooth headphones or speakers?).

Regardless what DAC (single, dual, or quad DACs), when it uses aptX BT, it is just using Qualcomm chipset in bluetooh headphones/speakers. Right?

Yes. It's like comparing Mp3 to AAC. Some find that AptX sounds better than other Bluetooth formats. It's just different lossy codecs being sent. When using Bluetooth it doesn't matter at all what DAC is used in the sending device as it is completely ignored.

 

[Brooko]

I think with the coming Android o + LDAC chipset, it will force aptX / aptX HD to free up the bundle restriction.
Actually, everyone should just hold on till 2018 to see more information.

Now the users just go crazy on all the marketing noise about aptX / aptX HD now.
But many don't read finance news about the strings they pull behind the curtain.

Unless a DAP brand is so proud to announce their bluetooth transmission by done with a 3rd party DAC, I keep my doubt on the whole thing.
*Remark: I just use SONY products for bluetooth listening at the moment. and waiting for Apple 10th anniversary to have good news about upgrades on audio quality.

I guess we'll wait and see what developments occur - but you've missed the point if you're purely talking about an Android SoC / Chipset - and not about the codec itself. No matter what happens at the moment it still lookks like this:

Digital File > Digital Source > Conversion to Bluetooth compatible digital codec > Bluetooth transmission > Receipt at headset/speaker > Conversion (by DAC) to Analogue > sound heard.

For an APTx example, this looks like:

Flac file on X7 > ADPCM conversion/compression > Bluetooth digital transmission > Receipt at headset/speaker > Conversion (by DAC) to Analogue > sound heard.

For my iPhone - it looks like this:

aac256 file on iPhone ES > Bluetooth digital transmission > Receipt at headset/speaker > Conversion (by DAC) to Analogue > sound heard.

All the discussion about chipset etc is really not addressing what actually goes on. it will be development of the codecs and transmission which will net the most potential gains.

 

[esprithk]

I guess we'll wait and see what developments occur - but you've missed the point if you're purely talking about an Android SoC / Chipset - and not about the codec itself. No matter what happens at the moment it still lookks like this:

Digital File > Digital Source > Conversion to Bluetooth compatible digital codec > Bluetooth transmission > Receipt at headset/speaker > Conversion (by DAC) to Analogue > sound heard.

For an APTx example, this looks like:

Flac file on X7 > ADPCM conversion/compression > Bluetooth digital transmission > Receipt at headset/speaker > Conversion (by DAC) to Analogue > sound heard.

For my iPhone - it looks like this:

aac256 file on iPhone ES > Bluetooth digital transmission > Receipt at headset/speaker > Conversion (by DAC) to Analogue > sound heard.

All the discussion about chipset etc is really not addressing what actually goes on. it will be development of the codecs and transmission which will net the most potential gains.

So, in the coming 2018, for bluetooth features, we as users only come to 2 options.

aptx / aptX HD by Qualcomm
LDAC by SONY

 

[Brooko]

So, in the coming 2018, for bluetooth features, we as users only come to 2 options.

aptx / aptX HD by Qualcomm
LDAC by SONY

- you can leave me out of the "we". aac256 is perfectly transparent to me - and the quality aspect has been more about the quality of the speakers / earphones. I'm perfectly happy with current aac. I may be in the minority though. Again - I have actually tested both aptX and aac - and they both sound great.

 

[esprithk]

- you can leave me out of the "we". aac256 is perfectly transparent to me - and the quality aspect has been more about the quality of the speakers / earphones. I'm perfectly happy with current aac. I may be in the minority though. Again - I have actually tested both aptX and aac - and they both sound great.

Hi, Brooko,
Yes, I agree that iPhone in both wired and bluetooth sounds alright.

 

[FiiO]

X7 supports aptx HD in future update.
**it is listed on a p t x . c o m

Dear friend,

We have contacted our manager about this. Seems the Qualcomm company makes a mistake in it. Sorry, the X7 may not support aptx HD.

Best regards