A Couple of Unrelated Questions about DSD Filters & Bluetooth Antennas

[ejr]

I have a couple of questions about DAC/preamps and audio components in general, stemming from the gaps in my knowledge, being self-taught.

1.) When I set up a new DAC, it asks me to choose a DSD Filter cutoff value. I usually just leave it to the default because I'm not sure what this is or what impact these values will have on the sound and/or performance. How do I determine which value to use?

2.) I recently saw a youtube video stating that you should remove the Bluetooth antennas from any device that isn't going to use Bluetooth to prevent interference. I never use it, but I have been installing the antennas that come with every device, just to keep from losing them if they one day became necessary. All my connections are wired and always will be. I once had a component that used a Bluetooth remote, though. It caused all storts of problems for my other equipment, turning things on and off at random. I never got to the bottom of the problem. I just returned the device with the remote. It wasn't worth the aggravation.

Thanks.

 

[somebodyelse]

1.) When I set up a new DAC, it asks me to choose a DSD Filter cutoff value. I usually just leave it to the default because I'm not sure what this is or what impact these values will have on the sound and/or performance. How do I determine which value to use?

What DAC is this? I don't think I've heard of a setting like that before. It seems like it might be a filter to cut some of the ultrasonic noise you'll see if you look at a wideband spectrum plot of DSD output, which technically isn't a bad idea. It runs counter to the usual pro-DSD argument that ultrasonic content matters though, so I'd be interested to see how the manual describes it.

2.) I recently saw a youtube video stating that you should remove the Bluetooth antennas from any device that isn't going to use Bluetooth to prevent interference. I never use it, but I have been installing the antennas that come with every device, just to keep from losing them if they one day became necessary. All my connections are wired and always will be. I once had a component that used a Bluetooth remote, though. It caused all storts of problems for my other equipment, turning things on and off at random. I never got to the bottom of the problem. I just returned the device with the remote. It wasn't worth the aggravation.

That's several statements without a question.

 

[Scytales]

I have a couple of questions about DAC/preamps and audio components in general, stemming from the gaps in my knowledge, being self-taught.

1.) When I set up a new DAC, it asks me to choose a DSD Filter cutoff value. I usually just leave it to the default because I'm not sure what this is or what impact these values will have on the sound and/or performance. How do I determine which value to use?

Andrew Demery, who worked for Philips and Sony at the time of the inception of SACD and is the co-author of the Sony Sonoma DSD digital audio workstation manual, once explained that some amplifiers may be disturbed by the ultrasonic energy produced by the shaped quantization noise that is a byproduct of the sigma-delta modulator used to produce DSD data-streams.

The disturbance manifests itself by audible spurious noises they used to called "birdies", a name that is self-explanatory about the nature of those spurious sounds.

When such audible distortion is heard, it means that the output of the DAC or the SACD player replaying DSD contents needs more low-pass filtering to remove more of the energy of the shaped quantization noise above the audio band to cease to disturb downstream device(s). Hence, different low-pass filter settings for DSD replay on many SACD players and DSD capable DACs. Their purpose is to help building whole systems free of "birdies" when they are encountered.

This kind of events seems extremely rare, as I have never heard or read a testimony of someone having suffered from them, but it is good to know the reason for this different low-pass filter settings, that can be implemented in the digital or in the analogue domain.

I have also seen one probable case of an old "vintage" amplifier instability (high frequency oscillation) apparently triggered by playing SACDs that an electronic repairer has documented in an Youtube video.

 

[ejr]

Thanks for your replies. I will try to answer your questions below.

1. I have a new S.M.S.L. DO400 DAC with a choice of four DSD filter settings. I also have a Loxjie D60 (which is basically their budget version of the same DAC) with the same filter settings. Both force you to pick one of them, so I am sticking with the lowest value on each (which is the default).

2. I thought it was obvious. Will it make any difference if I remove the Bluetooth antennas, since I am not using them? I don't stream music via Bluetooth and my only experience with it was a negative one, when a remote for another device caused problems with it .

For anyone who is interested (and there is a whole discussion about this in another forum on this site), so far the sound and performance of both DACs seem to be identical. I'd say the DO400 is worth the slightly higher price because the display screen on my D60 went wonky after about a year (when the warranty expired). It's nearly unreadable. The screen on the DO400 is smaller, though. So it's harder to read from across the room. But it looks like its higher quality.

I like the sound character of these DACs better than any of the others that I have tried. Both use the ESS ES9039MSPRO chips. I have always had very sensitive ears and could hear much higher frequencies than most people (my ENT says I am his only patient that got scores like that on hearing tests.) In my old age, that ability comes and goes. I also have to deal with tinnitus (which also fluctuates). DACs based on this particular chip seem to give me the fewest hearing problems. They also meet my asthetic preferences.

I am by no means an expert in this area, but it seems to me that most of the DAC chips I have heard -- whether they sound pleasing or not -- seem to be trying to expand the width and depth of the sound stage. The also seem to be trying to replicate the ambiance of the rooms where the sound of the tracks you are listening to were recorded. I can understand why people would like that, but I don't. The room I am listening in has a character of its own. My feeling is why lay the character of another room on top of that? I'd rather have as clear and uncolored signal as possible. The ESS chips that I have heard seemed to be the best in that regard. But they tend to be a little shrill on the extreme top end -- which, to my ears, tends to distort. The ES9039MSPRO is the only DAC chip that I have heard so far that mitigates it to my satisfaction.

 

[Vincent Kars]

I am sticking with the lowest value

DSD produces a lot of quantization noise that must be filtered out. 47 kHz is the lowest values, way beyond the upper threshold of our hearing (20 kHz). I don't see any reason to choose a higher value.

 

[ejr]

DSD produces a lot of quantization noise that must be filtered out. 47 kHz is the lowest values, way beyond the upper threshold of our hearing (20 kHz). I don't see any reason to choose a higher value.

That's very helpful. Thanks.

 

[RandomEar]

Thanks for your replies. I will try to answer your questions below.

1. I have a new S.M.S.L. DO400 DAC with a choice of four DSD filter settings. I also have a Loxjie D60 (which is basically their budget version of the same DAC) with the same filter settings. Both force you to pick one of them, so I am sticking with the lowest value on each (which is the default).

Default (lowest) is a good choice in this case.

2. I thought it was obvious. Will it make any difference if I remove the Bluetooth antennas, since I am not using them? I don't stream music via Bluetooth and my only experience with it was a negative one, when a remote for another device caused problems with it .

I would not remove the antenna. Bluetooth is extremely low power and I have never had any problems with interference on any device using it. And if you don't remove the antenna, you don't risk loosing it in that big box of random stuff in your attic

For anyone who is interested (and there is a whole discussion about this in another forum on this site), so far the sound and performance of both DACs seem to be identical. I'd say the DO400 is worth the slightly higher price because the display screen on my D60 went wonky after about a year (when the warranty expired). It's nearly unreadable. The screen on the DO400 is smaller, though. So it's harder to read from across the room. But it looks like its higher quality.

Sucks that the screen failed so early. If you feel comfortable opening it, you could check it it's just the display cable that might need to be re-seated.

I like the sound character of these DACs better than any of the others that I have tried. Both use the ESS ES9039MSPRO chips. I have always had very sensitive ears and could hear much higher frequencies than most people (my ENT says I am his only patient that got scores like that on hearing tests.) In my old age, that ability comes and goes. I also have to deal with tinnitus (which also fluctuates). DACs based on this particular chip seem to give me the fewest hearing problems. They also meet my asthetic preferences.

Let me put this gently: We all like to think that our senses are a bit above average. It's a bit of a golden ear thing with audio devices and hearing. I get it and - ironically - I hope the same is true for my ears. However, I have come to realize that in controlled tests, that notion fails quickly.

Modern DACs have surpassed the limits of human hearing and have done so quite some time ago. Think about current equipment like 5G or WiFi: Those use DACs in the GHz range with insane performance. Reproducing audio is not a challenging task anymore for modern hardware. The consequence is that DACs - with very few exceptions of bad designs and odd filters in boutique devices - don't have any sound signature anymore.

I am by no means an expert in this area, but it seems to me that most of the DAC chips I have heard -- whether they sound pleasing or not -- seem to be trying to expand the width and depth of the sound stage. The also seem to be trying to replicate the ambiance of the rooms where the sound of the tracks you are listening to were recorded. I can understand why people would like that, but I don't. The room I am listening in has a character of its own. My feeling is why lay the character of another room on top of that? I'd rather have as clear and uncolored signal as possible. The ESS chips that I have heard seemed to be the best in that regard. But they tend to be a little shrill on the extreme top end -- which, to my ears, tends to distort. The ES9039MSPRO is the only DAC chip that I have heard so far that mitigates it to my satisfaction.

Sound stage is a property of the recording and influenced by your speakers, your room and their interaction. DACs don't alter it in any way - if they did, they would fail at their one core assignment: Converting digital to analog as truthfully as possible. Distortion in current DACs is also far, far below the limit of audibility for all humans. DACs easily reach a THD of -120 dB, while humans typically fail to identify distortion around -40 dB with some edge cases in controlled tests reaching slightly below -50 dB.

 

[Vincent Kars]

Will it make any difference if I remove the Bluetooth antennas, since I am not using them?

Wonder what kind of devices you are talking about. My mobile or my Bluetooth earbuds don't have removable antenna's
The first thing is to check if the device is active.
You have a DAC with a Bluetooth input.
Is it actively broadcasting its presence when not selected as an input?
Do you see it in e.g. the list of BT devices on your mobile?
If not, why bother?
If it does, does it drop from this list when you remove the antenna?

 

[ejr]

It was a remote for an Apple TV box. It turned two older Sony Bravia TVs off and on at random in different rooms. Both had Android operating systems and were also connected to Roku boxes. Not sure what was responsible, but I had to not only disconnect the Apple TV, but put back in its box and insided a metal cabinet in a different room. I don't know enough about this to know the mechanics (or the electronics) of what was going on. What I do know is that's what it took to resolve the problem and it never occurred before or since.