Bluetooth headphones not loud or clear enough...

Bluetooth headphones not loud or clear enough...

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TameRacingDriver

Original Poster:

18,538 posts

279 months

Thursday 7th November
quotequote all
I imagine most people will be thinking something along the lines of "get better headphones" or "use wired headphones", but there's more to this problem than the title suggests...

Like most of you on this subforum, you will like your audio, and I am no exception. I have quite a nice speaker setup that I enjoy using, but also, I live in a terraced house, so while I can use those most of the time, at night there is sometimes a need to use headphones so that I don't piss my neighbours off if I want to listen to loud music or a movie at 2am.

I have a pair of B&W PX8 headphones, which were rather expensive to say the least, and my Mrs uses a pair of B&W P7 wireless headphones. Both of these are bluetooth headphones, and both are definitely what you would call 'decent' headphones.

But the problem I have is, whenever I connect them to my AV system, seemingly no matter how I do it, they just sound... crap. They just lack clarity, detail, oomph, and just don't go loud enough.

I know the problem isn't my headphones because when I connect them to my Samsung Tab S9 Ultra, they sound excellent. Plenty of detail, they go plenty loud, and are highly enjoyable to listen to.

In fact, my headphones never used to sound this bad on the system I had before (though granted, they still did not sound as good as through my tablet, but it was acceptable), but I have recently swapped out my amplifier, which has caused me to have to change the configuration of how I connect the headphones.

My previous system was setup like following: -

TV optical out (PCM) > Beresford Caiman II DAC > Marantz PM6006UK > Avantree Oasis BT Transmitter (connected to the tape out on amp) > Headphones

However, my amp would no longer fit in my new TV stand, so I had to buy a new amp. Only, the new amp doesn't have a tape out, so my system has been reconfigured, and goes like this: -

TV optical out (PCM) > Beresford Caiman II DAC > Avantree Oasis BT transmitter > Headphones

However, that's just not hitting the spot, as I said, it sounds flat and lifeless, and lacking in volume. Both headphones are, as they did before, connecting via AptX (not HD, the older P7s don't support AptX HD).

I also discovered my new TV supports bluetooth headphones, so I also tried connecting the headphones straight to the TV via BT, but it makes no real difference, it still sounds a bit crap.

I've also tried TV optical out (PCM) > Avantree > Headphones but that's no better either. If anything I prefer using the DAC because it simply sounds a bit better to my ears.

I'm struggling to understand what the problem is. The only thing I can think of is that the tape out signal from the old amp was louder or more powerful than the way I'm using it now.

It's frustrating because I know both pairs of headphones are capable of much better than they are, and indeed, when I connect my phone or tablet, they sound so much better.

So I'm really after some ideas of how I can make it better.

Are there BT transmitters that produce a more powerful signal?

Am I able to boost the signal output to the existing transmitter?

Or are there ANY other ideas, and I do mean, ANYTHING that would fit into my system and produce an enjoyable sound that doesn't make it sound like a massive downgrade compared to my speaker system?

clockworks

6,125 posts

152 months

Thursday 7th November
quotequote all
I'm using one of these, connected to my Denon AVR:

https://www.amazon.co.uk/dp/B0CC5LYCVC?ref=ppx_yo2...

TameRacingDriver

Original Poster:

18,538 posts

279 months

Thursday 7th November
quotequote all
Thanks for the suggestion, although I don't see it being any different to the Avantree Oasis Plus that I have now?

OutInTheShed

9,333 posts

33 months

Thursday 7th November
quotequote all
Some DACs in small boxes are known for having outputs which don't drive low impedance loads.
They need buffering by a pre-amp or something.
I have one of those cheap optical DACs which have been slated by lots of people, but it sounds fine driving an amplifier with a high impedance pre-amp.
i don't know if this applies to the pre-out of the Calman DAC but it's something you could look into.
A different BT transmitter might have a higher impedance input.

Another possibility is that there is a DC bias on the DAC output, and no DC block on the BT Tx input?

There are other bizarre possibilities like a cable that inverts one channel?
I'd fire up my scope.

clockworks

6,125 posts

152 months

Friday 8th November
quotequote all
Why do you have a standalone DAC connected between the source and the BT transmitter?
Surely that isn't needed - just use the optical input on the BT transmitter.

Unless I'm misunderstanding, you are currently converting the source digital signal to analogue in the DAC, then re-converting to digital in the BT transmitter, and back to analogue in the headphones.

TameRacingDriver

Original Poster:

18,538 posts

279 months

Friday 8th November
quotequote all
OutInTheShed said:
Some DACs in small boxes are known for having outputs which don't drive low impedance loads.
They need buffering by a pre-amp or something.
I have one of those cheap optical DACs which have been slated by lots of people, but it sounds fine driving an amplifier with a high impedance pre-amp.
i don't know if this applies to the pre-out of the Calman DAC but it's something you could look into.
A different BT transmitter might have a higher impedance input.

Another possibility is that there is a DC bias on the DAC output, and no DC block on the BT Tx input?

There are other bizarre possibilities like a cable that inverts one channel?
I'd fire up my scope.
Interesting, but I'm not sure if this is it because I'm having the same problem when connecting the headphones up directly to the TV via Bluetooth. The only thing I can think of is the tape output on the amp was giving a powerful signal which was effectively 'helping' the transmitter sound better than it was.


clockworks said:
Why do you have a standalone DAC connected between the source and the BT transmitter?
Surely that isn't needed - just use the optical input on the BT transmitter.

Unless I'm misunderstanding, you are currently converting the source digital signal to analogue in the DAC, then re-converting to digital in the BT transmitter, and back to analogue in the headphones.
That's a good question and I do / did have my reasons for that, believe it or not. I tried connecting the transmitter directly to the optical output originally, and then passing the optical through to the DAC and then to the speaker amp. I found that I had a similar issue that it sounded a bit crap.

So I decided to try using the DAC to output the signal to the speaker amp and then use the tape outputs to the transmitter and it just sounded better that way.

You're right, technically I don't need the DAC in this scenario but I figured the DAC was colouring the sound in a pleasing way to give me the sound I was after, so while it was technically wrong, it just sounded better to my ears.

However, it now seems to point towards the tape output giving a more powerful signal which is perhaps why I've found things to work they way they do because just using the DAC and then the transmitter, it's still a bit crap.

I hope that made (some) sense hehe

clockworks

6,125 posts

152 months

Friday 8th November
quotequote all
It kind of makes sense that a device "colours" the sound in a way that sounds pleasing, yes.

However, that fact that you say the headphones sound good connected directly to your phone or tablet suggests that you don't need to "colour" the sound.

Presumably you are connecting the headphones directly to the phone/tablet using the onboard Bluetooth?

TameRacingDriver

Original Poster:

18,538 posts

279 months

Friday 8th November
quotequote all
clockworks said:
It kind of makes sense that a device "colours" the sound in a way that sounds pleasing, yes.

However, that fact that you say the headphones sound good connected directly to your phone or tablet suggests that you don't need to "colour" the sound.

Presumably you are connecting the headphones directly to the phone/tablet using the onboard Bluetooth?
Yeah that's right, just a straight connection to my tablet / phone, and this seems to give the best sound of all of the devices I've tried.

I just don't get why the TV / transmitter both sound so much quieter, and less detailed. Really odd. Could my mobile devices be enhancing the sound somehow? I've checked and I've got Atmos turned off, no EQ etc etc...

JimbobVFR

2,727 posts

151 months

Friday 8th November
quotequote all
Do you have the Caimen DAC set to fixed or variable output, I believe it has a volume knob on the front and can be set to variable output, perhaps a tweak more volume might help.

Does your Bluetooth transmitter perhaps have its own volume. I used to have one where both the BT device and the headphones had essentially their own volume setting and it would sound a bit rubbish if the transmitter was set too low.

TameRacingDriver

Original Poster:

18,538 posts

279 months

Friday 8th November
quotequote all
JimbobVFR said:
Do you have the Caimen DAC set to fixed or variable output, I believe it has a volume knob on the front and can be set to variable output, perhaps a tweak more volume might help.

Does your Bluetooth transmitter perhaps have its own volume. I used to have one where both the BT device and the headphones had essentially their own volume setting and it would sound a bit rubbish if the transmitter was set too low.
I've got the Caiman set to fixed, as I assumed this would be loudest anyway. However it may be worth a try setting it to variable and maxing the volume.

In theory it does have volume controls but when I tried it didn't seem to do anything, and when I've looked it says:

Avantree Website said:
You may adjust the volume via the "+" and "-" buttons directly on the Oasis Plus transmitter. This can ONLY be done if your headphone/speaker supports AVRCP (most of the ones with volume adjustment buttons do.) you may adjust the volume directly via your TV / AV Receiver's remote control
Which suggests that the volume controls on transmitter are linked and therefore the same, so I was just trying to adjust the volume up the same as I would have on the headphones themselves, ergo it wasn't getting any louder.