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How to increase gain between BT transmitter and Philips Sound bar?

Audiolab 6000A Amplifier

swamytk

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I have my projector audio out connected to Bluetooth transmitter through a Chromecast HDMI to optical converter. On screen side I have a Philips Sound bar in Bluetooth mode. This is a poor man's HT setup in a rented house without cabling.

My problem is in general Sound bar volume is good. but when I stream a movie to Chromecast the volume is lesser comparing other sources connected to Sound bar. I would like to improve gain between this link. Suggestion please.
 

MaSh

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I have my projector audio out connected to Bluetooth transmitter through a Chromecast HDMI to optical converter. On screen side I have a Philips Sound bar in Bluetooth mode. This is a poor man's HT setup in a rented house without cabling.

My problem is in general Sound bar volume is good. but when I stream a movie to Chromecast the volume is lesser comparing other sources connected to Sound bar. I would like to improve gain between this link. Suggestion please.
Wow, that's a nice setup. Complicated but nice. Looks like in this setup, there are only two volume controls in play. One in the source and second in the soundbar. Ideally, you should have your Source volume at MAX and then just play around with the Sound Bar volume. Is the Soundbar in Stereo Mode?

MaSh
 

swamytk

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Ideally, you should have your Source volume at MAX and then just play around with the Sound Bar volume. Is the Soundbar in Stereo Mode?

MaSh
Yes, Chromecast volume is at max. Sound bar is 2.1 so I have set it as Surround instead of Stereo. I have also set Sound mode as Warm. Does it make difference in gain?
 

MaSh

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Yes, Chromecast volume is at max. Sound bar is 2.1 so I have set it as Surround instead of Stereo. I have also set Sound mode as Warm. Does it make difference in gain?
Well in my opinion that's where the issue is. When the soundbar is Stereo (2.1), why run it in Surround mode? I think that is what is eating up the volume which is a very common thing that happens. Hence asked you about it in the previous post. Switch it back to Stereo mode and check how the sound is.

MaSh
 

swamytk

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Well in my opinion that's where the issue is. When the soundbar is Stereo (2.1), why run it in Surround mode? I think that is what is eating up the volume which is a very common thing that happens. Hence asked you about it in the previous post. Switch it back to Stereo mode and check how the sound is.

MaSh
It was my bad understanding that Stereo meant L/R SPK only. Let me try and will update here. Thanks, @MaSh
 

swamytk

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@MaSh As you have suggested Stereo mode gives a little higher volume, that is good one. But still it is not significant. I am not sure whether it is BT transmitter's limitation. Let me check with other speakers and amps. Thanks.
 

MaSh

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It was my bad understanding that Stereo meant L/R SPK only. Let me try and will update here. Thanks, @MaSh
Yes when in strereo mode and if there is a Sub connected, the Soundbar will drive the speakers and the sub Without Processing. When you add the surround mode, there is internal Processing of the sound which affects the SPL.

@MaSh As you have suggested Stereo mode gives a little higher volume, that is good one. But still it is not significant. I am not sure whether it is BT transmitter's limitation. Let me check with other speakers and amps. Thanks.
Hmm okay. Are you having to run it at max volume?

MaSh
 

swamytk

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Yes when in strereo mode and if there is a Sub connected, the Soundbar will drive the speakers and the sub Without Processing. When you add the surround mode, there is internal Processing of the sound which affects the SPL.
When the Sound bar itself is 2.1, why does it process sound for surround? It is just a marketing gimmick or any genuine reason?

Hmm okay. Are you having to run it at max volume?
MaSh
The volume differs from streaming app to app. I would like to boost volume for such low volume app cases :)
 

MaSh

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When the Sound bar itself is 2.1, why does it process sound for surround? It is just a marketing gimmick or any genuine reason?


The volume differs from streaming app to app. I would like to boost volume for such low volume app cases :)
Yes it's a mode, cannot be compared to an actual surround sound system.

Yes different apps can have different levels. That's one of the reasons I switched from chrome cast to firestick. Firestick is also not perfect but I found it better.

MaSh
 

swamytk

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That's one of the reasons I switched from chrome cast to firestick. Firestick is also not perfect but I found it better.
Yes, me too have a Firestick (Full HD model) lying idle. Since this projector is very low resolution, it is difficult to read and use the app on screen. Where as Chromecast gives freedom of controlling everything on Mobile. I tried to use casting function of Firestick, it is laggy and unreliable - so ended up with Chromecast. I was a happy user of Firestick along with my old Sony LCD. After buying New Sony LED TV + Nvidia Shield Pro, Firestick is lying idle.
 

swamytk

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I have fixed the issue at last :cool: :).

My setup is bit complex to root cause the issue.
Egate i9 Projector | Firestick or Chromecast -> HDMI to SPDIF Digital audio converter --- SPDIF ---> Phoenix BT 5.0 (2.1 mode) Transmitter ----))))))))))))))))))--- Ding Shine BTS2 Bluetooth 5.0 HD Receiver --- Coax cable ---> FX Audio DAC X6 or Fiio D03K DAC ----- RCA L/R ----> (earlier Philips Sound bar) Marantz PM5005 -> Yamaha YST-315 Sub -> Wharfedale Diamond 220

In this chain since both the DACs were culprits it was difficult to root cause. Both of them caused low gain input to Amp. Then I found through online sources that Fx Audio DAC X6 has two jumpers on board for gain control; by default they are set low gain control. But these are only for headphone out of DAC where as I used RCA L/R out. So I decided to change output from RCA L/R to Headphone out; and also to change the jumper to high gain mode. It worked :)

Ding Shine BTS2 Bluetooth 5.0 HD Receiver --- Coax cable ---> FX Audio DAC X6 ----- Headphone Out ---->

How I changed jumper:
1. Removed four screws on front panel of FX Audio DAC X6, took the board out.

IMG_20200629_190645.jpg


IMG_20200629_190947.jpg

2. Found two jumpers just behind headphone jack. They were set away from headphone jack side. i.e., Low Gain mode.

Low Gain.jpg

3. Moved both the jumpers close to headphone jack side., i.e., High Gain mode.

High Gain.jpg

That is it. Hooked up headphone out to Amp RCA input through a cable. Wow, it is a great improvement. It was as great as bypassing BT path and connecting directly through Coax.

@MaSh
 

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MaSh

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Oh wonderful. Excellent update. Do you see any change in Sound Quality using the headphone out?

You could compare the DAC output volt and the stereo amp's input volt. Usually the dacs have 1-2v output.

So right now, you have maxed out the volume on the dac and using Marantz volume control?

MaSh
 

swamytk

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Do you see any change in Sound Quality using the headphone out?
Definitely I can hear much better quality sound (crisp) from headphone out than RCA out. It looks like even BT Tx/Rx path in between did not impact the quality of sound. For testing I connected HDMI to Digital out's Coax output directly to DAC through a long cable and compared this with BT path by keep switching Amp input between these two inputs. I don't hear any significant difference. Both the BT Tx and Rx are 5.0 Aptx supported.

So right now, you have maxed out the volume on the dac and using Marantz volume control?
Partially Yes. I have kept DAC volume at around 80% to avoid any clipping and using Marantz volume control. Does it make sense?
 

swamytk

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You could compare the DAC output volt and the stereo amp's input volt. Usually the dacs have 1-2v output.
Here are the voltage related spec parameters for both. It looks like both are 2V. How to interpret this? @MaSh

FX Audio DAC X6:
  • Line level output: RMS 2V
  • Recommended headphone impedance: 32 – 600 ohm
  • Output power: 90 mW / 600 ohm, 180 mW / 300 ohm, 450 mW / 100 ohm, 610 mW / 62 ohm, 910 mW / 32 ohm, 1,000 mW / 16 ohm
PM5005 Spec:
Input Sensitivity: MM2.2 mV / 47 kOhm
Signal to Noise Ratio: MM83 dB
Input Sensitivity: High level200 mV / 20 kOhm
Signal to Noise Ratio: High level103dB (2V input)
 

dazzwilliams

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My setup is bit complex to root cause the issue.
Egate i9 Projector | Firestick or Chromecast -> HDMI to SPDIF Digital audio converter --- SPDIF ---> Phoenix BT 5.0 (2.1 mode) Transmitter ----))))))))))))))))))--- Ding Shine BTS2 Bluetooth 5.0 HD Receiver --- Coax cable ---> FX Audio DAC X6 or Fiio D03K DAC ----- RCA L/R ----> (earlier Philips Sound bar) Marantz PM5005 -> Yamaha YST-315 Sub -> Wharfedale Diamond 220
Can you give a short review about the Fiio D03K DAC? Does it really lead to low gain?
I just got it hoping to connect the coaxial out from my TV to Norge Amp via this Fiio DAC.
 

swamytk

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Can you give a short review about the Fiio D03K DAC? Does it really lead to low gain?
I just got it hoping to connect the coaxial out from my TV to Norge Amp via this Fiio DAC.
I believe it depends on Amp connected. In PM5005 case I see a lower gain with D03K too. Where as Fx Audio DAC X6 gives worser gain than E03K. At least X6 has gain jumpers, not sure about D03K.
 
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