Bluesound Node X as a 2.1ch pre-amplifier
Answered
Hello All,
I would like to upgrade to the Node X, mainly for the upgraded ESS-based DAC and headphone amplification - I've heard great reviews.
I am also looking to use the HDMI eArc capabilities of the Node X and connect it directly to my OLED TV as part of a 2.1ch setup. Two points that I was curious about, however:
- Can I expect any degradation of sound quality when using the Node X to control volume? I would like the system volume to be driven by the TV remote when in use, effectively making the Node X my "pre-amplifier".
- Will the subwoofer output at the back of the Node X pass LFE (Low Frequency Effects) information to my subwoofer? I know this information will be present in the signal received via HDMI eArc, it would be great if I can get the most out of my subwoofer when watching movies on the same system.
Any guidance from the forum will be greatly appreciated!
Many Thanks,
Sumant
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Official comment
There is no degradation of sound using the volume control of the NODE.
The NODE does not support any formats other than Stereo PCM, so any LFE originating from the TV will not be passed. The NODE will output low frequencies that are part of a stereo mix via the subwoofer output.
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Thanks for the quick feedback Seppi!
I was worried about degradation of the sound with volume control, because I wasn’t sure if it was modulated in the digital or analogue section of the device. Would you know where the volume control happens?
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It’s done in the digital domain.
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Am I correct in assuming that attenuation in the digital domain will reduce the utilisation of the DAC i.e. there will be fewer bits for it to play with, and therefore lower resolution?
To my understanding, attenuating volume in the digital domain to 25% would present the DAC with a signal which will be converted with 2bits fewer, and therefore resolution will be around a quarter of what it would have been without the digital attenuation.
The reason I ask is that I am considering connecting the RCA outputs on the back of the Node X directly to a power amplifier in future. Maybe I should consider something like an inline attenuator, or a passive volume control in between, in order to minimise the loss in resolution?
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I don’t have the details to hand but there is plenty of overhead in the digital circuits to shift the level without any audible effect and not something I would worry about. I am just a user like yourself.
You will certainly degrade the audio signal with additional cabling and an attenuator - even an expensive stepped actuator as anything in the signal path acts as a filter, cabling has inductance, capacitance as well as resistance.
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Digital volume control used to be something to avoid like the plague. With only 16-bits, losing some bits can be devastating. Nowadays, digital volume control is done with 24 or even 32 bits. If properly implemented, there should be no degradation to concern about.
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Thank you both, your input is much appreciated!
It seems like the volume control may indeed be done at 32bits, or 24bits as a minimum. The Node (regular, not X) is advertised for streaming functionality up to 24bits, however the DAC design quotes 32-bit.
Maybe it is these 8-bits of "headroom" that will be consumed for digital volume control?
Would anyone know if this can be confirmed by someone technical from Bluesound themselves?
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Ken is correct and yup Sumant that's why it's 32-bit DAC for 24-bit content.
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Fantastic, thanks Tony!
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What power amp are you using with the Node?
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I’m currently using Bluesoud Node X as a DAC/pre-amp with an Emotiva basX A2 power amplifier connected to a pair of Focal Vestía N1. I like it. It’s a simple solution but sounds great.
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