What does a multibit dac do?

[spwath]

So they seem to be getting a lot of praise, but what exactly do they do?

[SSL]

Simplifying, they preserve the original samples.

 

Our music is encoded using pulse-code modulation (PCM), which represents audio as samples of the signal amplitude. However, the vast majority of DACs these days actually perform their decoding using a pulse-density modulation (PDM) signal, using a technique called delta-sigma modulation. These kinds of DACs are commonly referred to simply as "delta-sigma" to differentiate from multibit.

 

The supposed problem is that delta-sigma DACs, in order to do their decoding, much discard the original PCM samples when they convert to PDM. Further, delta-sigma DACs are typically 1-5 bits, making up for the lost dynamic range with extremely high oversampling - e.g. in the MHz range.

 

Multibit solutions overcome these supposed drawbacks by decoding the audio signal with a true 16+ bit DAC, preserving the original PCM samples.

 

On top of this, Schiit has layered a proprietary closed-form, frequency- and time-domain optimized digital filter. Digital filters are necessary to perform upsampling of the audio signal, which moves aliasing distortion out of the audible band. Some typical methods for this are the minimum-phase and linear-phase filters. Some people claim that minimum phase filters are better because they avoid pre-ringing, while other prefer linear phase because they avoid phase-distortion. I'm not sure how Schiit's closed-form filter differs from linear-phase, other than it is supposed to preserve all of the original samples.

 

Whether or not any of this is audible is up to the listener, I guess. I haven't heard a multibit DAC, although I'd like to. More than one person has claimed not to have heard a difference between the Schiit Bifrost multibit and other DACs, like the ODAC, in blind AB/X testing.

[spwath]

1 minute ago, SSL said:

Simplifying, they preserve the original samples.

 

Our music is encoded using pulse-code modulation (PCM), which represents audio as samples of the signal amplitude. However, the vast majority of DACs these days actually perform their decoding using a pulse-density modulation (PDM) signal, using a technique called delta-sigma modulation. These kinds of DACs are commonly referred to simply as "delta-sigma" to differentiate from multibit.

 

The supposed problem is that delta-sigma DACs, in order to do their decoding, much discard the original PCM samples when they convert to PDM. Further, delta-sigma DACs are typically 1-5 bits, making up for the lost dynamic range with extremely high oversampling - e.g. in the MHz range.

 

Multibit solutions overcome these supposed drawbacks by decoding the audio signal with a true 16+ bit DAC, preserving the original PCM samples.

 

On top of this, Schiit has layered a proprietary closed-form, frequency- and time-domain optimized digital filter. Digital filters are necessary to perform upsampling of the audio signal, which moves aliasing distortion out of the audible band. Some typical methods for this are the minimum-phase and linear-phase filters. Some people claim that minimum phase filters are better because they avoid pre-ringing, while other prefer linear phase because they avoid phase-distortion. I'm not sure how Schiit's closed-form filter differs from linear-phase, other than it is supposed to preserve all of the original samples.

 

Whether or not any of this is audible is up to the listener, I guess. I haven't heard a multibit DAC, although I'd like to. More than one person has claimed not to have heard a difference between the Schiit Bifrost multibit and other DACs, like the ODAC, in blind AB/X testing.

Interesting.

And now their is the $250 schiit modi multibit. Low price compared to other multibits

[SSL]

2 minutes ago, spwath said:

Interesting.

And now their is the $250 schiit modi multibit. Low price compared to other multibits

 

I believe it is the least expensive multibit DAC, period, and by a large margin. I'm sure if they could make one for cheaper, they would.

[SSL]

http://archimago.blogspot.de/2016/07/musings-digital-interpolation-filters.html

 

This article provides some info on what digital filters are supposed to do and how they affect the audio signal. I don't think it specifically covers closed-form filters, though.

[spwath]

Just now, SSL said:

 

I believe it is the least expensive multibit DAC, period, and by a large margin. I'm sure if they could make one for cheaper, they would.

Yeah. Thats what makes Schiit great. and they dont even try to oversell their products.

The wyrd page basically tells people it may or may not do anything

1 minute ago, SSL said:

http://archimago.blogspot.de/2016/07/musings-digital-interpolation-filters.html

 

This article provides some info on what digital filters are supposed to do and how they affect the audio signal. I don't think it specifically covers closed-form filters, though.

great thanks, ill give that a look

[Dackzy]

aww I was ready to get nerdy and then I see that SSL already did it...

[Guest]

On 2016-08-14 at 9:39 PM, SSL said:

Simplifying, they preserve the original samples.

 

Our music is encoded using pulse-code modulation (PCM), which represents audio as samples of the signal amplitude. However, the vast majority of DACs these days actually perform their decoding using a pulse-density modulation (PDM) signal, using a technique called delta-sigma modulation. These kinds of DACs are commonly referred to simply as "delta-sigma" to differentiate from multibit.

 

The supposed problem is that delta-sigma DACs, in order to do their decoding, much discard the original PCM samples when they convert to PDM. Further, delta-sigma DACs are typically 1-5 bits, making up for the lost dynamic range with extremely high oversampling - e.g. in the MHz range.

 

Multibit solutions overcome these supposed drawbacks by decoding the audio signal with a true 16+ bit DAC, preserving the original PCM samples.

 

On top of this, Schiit has layered a proprietary closed-form, frequency- and time-domain optimized digital filter. Digital filters are necessary to perform upsampling of the audio signal, which moves aliasing distortion out of the audible band. Some typical methods for this are the minimum-phase and linear-phase filters. Some people claim that minimum phase filters are better because they avoid pre-ringing, while other prefer linear phase because they avoid phase-distortion. I'm not sure how Schiit's closed-form filter differs from linear-phase, other than it is supposed to preserve all of the original samples.

 

Whether or not any of this is audible is up to the listener, I guess. I haven't heard a multibit DAC, although I'd like to. More than one person has claimed not to have heard a difference between the Schiit Bifrost multibit and other DACs, like the ODAC, in blind AB/X testing.

@SSL and @Dackzy ... I went to a dinner party with my wife last night. Her husband is a semi-retired, sound engineer.  I let him unbox my newly-purchased Modi-Multibit & Magni-3 (whoop whoop!).  He was intrigued with these little silver boxes.

I’ve been following your posts since last year, btw. You’ve saved me from wasting a lot of money on my new-found, mid-life hobby.

...AND... I could understand some of what the sound engineer was talking about as he chittered on about bitrate, AB/X testing, DAC.... ack ack ack!!!!!

 

Keep posting, eh. I’m one of many who undoubtably watch your posts with interest.

Sincerely,

PrometheanCat in Toronto, Ontario, Canada.  Jan. 4, 2018.

[an actual squirrel]

These aren't great answers to this question. Put simply, higher bit depth dacs mean a lower noise floor, but the trade off is that the accuracy of the volume steps becomes worse.

[Xii-Nyth]

On 1/4/2018 at 8:48 AM, Guest said:

I went to a dinner party with my wife last night. Her husband is a semi-retired, sound engineer.

huh