In a perfect world, where would the D to A conversion occur?

[sdolezalek]

I have been wondering whether in a computer audio world, we would actually be best served by having the signal remain in the digital domain all the way to the individual speaker driver? I know there are some medium-fi powered studio monitors that can handle the signal that way, but I assume that neither their DAC's nor their amplifiers are really up to C.A.S.H. standards. But, what if a higher quality speaker manufacturer really implented such a solution -- would you buy it and would it further reduce other variables, i.e. cabling, signal loss, etc.?

 

I also recognize the benefit of domain excellence between speakers, DACs and amplifiers and that a jack of all trades is likely to be inferior; but don't rule out a collaborative effort between category leaders. I guess, put differently, my real question is how much variability is introduced by plugs, cables, and rossovers all acting in the analog domain?

 

[The Computer Audiophile]

Hi JSD - I'm open to any solution that leads to better sound quality.

 

I've often thought that manufacturers whose equipment works well together should team up to build certain components. For example I would love a Magico powered speaker with Spectral Audio amplification built-in.

 

[mwheelerk]

Like these

 

http://www.dedicatedaudio.com/inc/sdetail/4705/33057

 

[esldude]

Tact Audio in the 2150 XDM like I have keeps everything digital until the actual output stage of the unit. The output stage is good for 150 wpc into 8 ohms. It really doesn't become analog until the output stage only. That is a switching amp running at I think 410,000 hz switching rate. That has some real advantages keeping analog noise out of the picture until you are dealing with higher current and lower impedance at the speaker level.

 

The same thing carried on to each driver of the speaker would be the next step. And if your pocket book is deep enough Tact offers you the ability to use multiple amps that all talk to each other and do just that.

 

Of course Meridian has offered speakers that have dedicated built in amps for each driver with individual (I believe digital crossovers) with DAC's feeding the result to each driver/amp in the speaker. They have that for surround and stereo use. They have a rep for making pretty good equipment. So not sure what you would lose there.

 

I do agree that high level crossovers in speakers is an area that could have already been improved upon by doing crossovers digitally and feeding the result to the amp for each driver. It apparently just doesn't market well though I think it should.

 

[realhifi]

"I've often thought that manufacturers whose equipment works well together should team up to build certain components. For example I would love a Magico powered speaker with Spectral Audio amplification built-in."

 

Not even Magnepan and Audio Research (THE longest running love affair in hifi) would do that. Much like the infamous Linn and Naim marriage, they all seem to end in a divorce. If you want Spectral, the next guy will want Classe...just the nature of our hobby. Closest to that you see is at shows where two greats will display together and even that is so political they usually have to display with someone different the next year.

 

[goldenpiggy]

In the automotive and professional audio world, its common to have the amp(s) right in the speaker enclosure. A lot of it has to do with cost (wiring), distance from source (you can run AES/EBU over CAT5 for over 300ft with no problem), and eliminating the amp rack (e.g. powered line arrays.) Many automotive and professional audio applications feed the amps located near or in the speakers with digital data, not analog. In an electrically noisy environment, it's simply more robust.

 

Good things with having a crossover/amp at the speaker: crossover happens on the low level source signal, so no power loss as with passive crossovers, little or no phase shift, drivers can be time-aligned and frequency response/abnormality compensated. You can have crazy crossover settings like 48dB/octave which is totally impractical with passive crossover. Bi or tri-amping is a lot easier as everything is self-contained.

 

Most of the powered speakers use class-D amps for space, power, thermal, and weight reasons. Nothing against them -- some of the newer designs are simply fantastic. But a lot of people still feel they are inferior to traditional Class A and A/B designs.

 

In the home hifi world, I think people are really conscious about matching components and sounds to their taste. This is where all-in-one may not work.

 

Just my two cents.

 

[20hertz]

http://www.genelec.com/8260a/?gclid=CJOu9tLsi68CFeJMpgodogo1-A

Great speakers!

 

[ccclapp]

I've heard of digital amps, but never fully understood...are the DACs in the amp and after or before the amplification??

 

Also isn't one disadvantage to all-in-speaker or all-in-amp that one is then forever married to all components in the setup, no swapping DACs, for example?

 

Thanks

 

[wgscott]

"Digital amps," at least when used to describe Class D amps, is a misnomer. The input and output are just like any other amp, and there is no ADC/DAC stage inside.

 

[mwheelerk]

I would think to some, me included, that the all-in-one solution would be a negative exactly because of the limitation in not being able to upgrade a specific aspect or component of the system. I am sure for many others the simplicity of that type of system is very appealing and my point would be a non-issue.

 

[ccclapp]

""Digital amps," at least when used to describe Class D amps, is a misnomer. The input and output are just like any other amp, and there is no ADC/DAC stage inside."

 

1) Are there true digital amps?

2) If not, is the only thing different about these that the analog wires are shorter?

3) Where is the pre-amp in the "digital amp" mix?

4) Do they always run to powered speakers, or not necessarily?

 

Thanks

 

[f1eng]

Have a look at this.

Transparent, in my opinion, so upgraditis can stop, or it has for me, apart from ending up with two as mono blocs.

I have compared it to high end SS and met an Audiophile who has replaced his Kondo valve kit too.

 

http://www.devialet.com/

 

OTOH if your passion is box swapping it kills the hobby for you!

 

[DigiPete]

I have no doubt the theoretically best topology is:

 

- Use digital X- over for bi- / tri- / quad-amping.

- Connect speakers to source with a digital signal that includes exact time signal like AES/EBU.

- Have a real digital amp like the Devialet feeding each driver.

- Stick in gentle DSP first in the chain for room correction and SUB integration.

- Integrate all in the speakers like in Genelec 8260's or directly next to them.

 

While this is beautiful and cost efficient, it's probably too complicated for the typical smaller audiophile enterprises.

 

 

A few solutions have achieved great sonic results with most of the above:

 

Steinway Lyngdorf - integrated system

Meridian - integrated system

behold - UPA192 Tri-Amping Mono Block with digital X-over.

 

I run 3 Genelec 8260's as fronts in my audiophile 5.1 setup.

They use:

 

- DSP Room correction

- Digital X-over

- Tri-DAC's

- Tri-amping - Class A/B, not digital

- Coaxial treble / mid-range driver covering from 800Hz

- Volume control over network

- Instant room correction changes

- Std. AES/EBU digital cables

- Perfect sub integration.

 

All in all stunning sound for USD 5000 a pop through better topology and perfect integration.

 

I just wish more had the balls to think out of the boxes. ;-)

 

[ccclapp]

...responding to Pete's config. Tell me where my thinking goes wrong:

 

Because:

 

A) JRiver MC now does:

-- digital x/o limited only by your outputs

-- DRC using 64 bit convolution filters (is my terminology off?)

-- 64 bit volume control

-- Multi-zone if desired (or set up as DRC "presets" for a single zone)

-- DSD and every other format known to man

-- dts decoding if/when desired

-- etc

 

B) Audiophile M-Ch dacs are affordable: Mytek 8x192, exa U18 ($2k)

and/or available as DIY (Buffalo-III 8-ch all in w usb->i2s) ($1k)

 

How does the above differ from: JRMC PC->m-ch DAC->(amp)/speaker driver?

 

Is it only a little more distance between DAC and speaker? Or, is it ONLY the preference for an integrated solution vs the above very easy manual solution?

 

I'll take interchangeability whenever possible, unless there is a powerful reason to give it up.

 

Please explain

 

[DigiPete]

Tell me where my thinking goes wrong

 

Shurely nothing is wrong, it sounds like a really nice setup, but we were talking about a perfect world.

 

There I would expect:

 

- Optimum system topology, removing inefficient solutions like analoge speaker cables.

- Optimum part topology, i.e. pure digital amplification with no DAC's

- All parts mass-produced for highest quality for the price.

- All parts optimized to fit together.

 

All technologies mentioned are known, what is lacking is primarily:

 

- Topology

- Mass production

 

More bang for the buck, that's what it is about!

 

 

Where do you get your kicks, that is the question:

 

a) Tweaking?

b) Listening to music with the most beautiful sonic presentation?

 

Go for your solution if a), go for my solution if b).

[ccclapp]

Pete

 

In the spirit of friendly banter I would add:

 

"Where do you get your kicks, that is the question:"...

 

...what if, for example, I get my kicks from dsd and the dacs in the integrated unit don't support dsd, than what?

 

...what if I like the drc filters made by rew or by audiolense , etc better than what's built into my integrated units auto drc settings or in 3 yrs time domain drc algorithms improve, then what?

 

... Or I want to add an office zone off my main system so I can get kicks while I work, then what?

 

Now a serious question:

 

I asked earlier " what is a digital amp" and if they actually exist. Your system description included non digital amp w ad converter near speaker. My main question here (vs why you didn't do dig amp) is what is a digital amp and how does it drive speakers?

 

Thanks

 

 

 

 

[Codifus]

http://nadelectronics.com/articles/The-M2---Future-of-Amplification

 

Technologies such as this amp show that the trend is to keep the signal digital for as long as possible.

 

1st the DAC was inside the CD player.

Second the DAC is standalone.

Now 3rd the DAC is starting to move from the standalone to the amplifier.

 

Something tells me that the amplifier will probably be the best and last spot for the DAC given that the only next step is the speaker itself. If you have DA conversion in the speaker, you have to have amplification in the speaker as well. Convenient from a physical standpoint, but technologically messy. DA conversion, amplification and transducer all in one would entail compromises to have all 3 functions in 1 location.

 

 

CD

 

[DigiPete]

@ ccclapp

 

Relevant questions:

 

"Where do you get your kicks, that is the question:"...

 

...what if, for example, I get my kicks from dsd and the ADCs in the integrated unit don't support dsd, than what?

 

The system should take up to DXD and DSD in the perfect world.

No reason why it is should no be doable.

 

...what if I like the drc filters made by rew or by audiolense , etc better than what's built into my integrated units auto drc settings or in 3 yrs time domain drc algorithms improve, then what?

 

A very good question.

Build in DSP can normally be turned ON and OFF, just do your stuff the way you like it.

I think most will leave it to the pro's to take care of that if the unit is well made.

 

... Or I want to add an office zone off my main system so I can get kicks while I work, then what?

 

Just choose Office zone on the controlling remote/iPad/voice recognition.

 

Now a serious question:

 

I asked earlier " what is a digital amp" and if they actually exist. Your system description included non digital amp w ad converter near speaker. My main question here (vs why you didn't do dig amp) is what is a digital amp and how does it drive speakers?

 

I define a a digital amp or power DAC as an intelligent fusion of the DAC and amp.

Think of it at a very precise super high switching frequency converter like a VFD (variable frequency drive).

A/D may be done in the last stages or in the actual speaker drivers.

 

This could be a Pulse Width Modulation (PWM) system.

The switching devices are either fully on or fully off, so no power is wasted and the efficiency approaches 100%.

A hefty low-pass filter would probably be needed to be in series with the output in order to prevent the high level of high-frequency switching noise from contaminating the neighborhood, and to reconstruct the analog waveform.

 

 

I have seen a few digital amps:

 

- TACT - the Millennium in 1998

 

- Lyngdorf - TDAI 2200 in 2006 (Total Digital Amplifier Integrated)

 

- Steinway Lyngdorf - Model D Sound System in 2007

 

- NAD - M2 in 2010 #

 

- Sharp - SM-SX100 digital integrated amplifier in 2000 ##

 

- Wadia - 151PowerDAC mini ###

 

- Devialett

 

 

Peter Lyngdorf is the common figure behind the first four.

 

Peter owned or was co-owner of several prominent high-end companies, including Snell Acoustics, NAD Electronics and Gryphon Audio. At Snell, he developed the world’s first full-range DSP room-correction device.

 

Peter Lyngdorf also founded, and is the majority shareholder of, AudioNord International, Europe’s most successful audio specialist group, encompassing Hi-Fi Klubben, Scandinavia’s largest Hi-Fi importer and retailer with over 70 points of sales, and Dali A/S, a global loudspeaker manufacturer.

 

Less known, Peter was also the original financier of Toccata Technology ApS, which is credited with creating the world’s first true digital amplifier, the legendary Millennium, in 1998. Toccata Technology has been sold to Texas Instruments but Lyngdorf has rights to the use of the digital amplification technology.

 

Heard of the "RoomPerfect" room correction - yes that patent was file by Lyngdorf audio in 2006.

 

 

My hope is that Peter finds a way to combine all his interests and connections and give the world something as fantastic as the Steinway Lyngdorf products but in a more approachable price range.

 

 

# The NAD M2 uses a Pulse Width Modulation (PWM) system from British semiconductor company, Diodes Zetex Ltd. that is not related to the Toccata technology or Lyngdorf.

 

## The SM-SX100 was really a DSD power DAC running direct PWM output at 2.82MHz.

It had a 1-bit/2.82MHz A/D sampling rate and the 2.82MHz DSD input for SACD playback.

Well reviewed, however at USD 15.000 for a 100W integrated amp may have been over the top for the time.

 

### The original Wadia company bet the farm on what they called a PowerDAC, but couldn't bring it to market successfully. 151PowerDAC mini uses PWM.

[DigiPete]

No real systems are perfect, so let me give a short comment on the four that I mentioned:

 

Steinway Lyngdorf - integrated system

Expensive, expensive, expensive.

Way out of my range for a surround system and huge in size.

 

Genelec 8200 series - speakers

My chosen cup of the, but not a solution without compromises!

It's PCM only, and restricted to 24/192 - that is it seems to run 24/96 internally.

Everything runs class A/B, so my 5.1 idle power is 145w.

The system needs AES/EBU input with a top notch clock.

DSP room correction is restricted to 4 notch and 4 shelves.

I can't design the freq. response, it just goes for linear.

 

Meridian - integrated system

Expensive, proprietary system, somehow not my cup of the.

 

behold - UPA192 Tri-Amping Mono Block with digital X-over.

Small company that seems somewhat erratic in its behavior.

Bass amp is digital, mid and treble is analogue.

The UPA192 is a nice concept, however I suppose you have to go to Germany to hear it and find out what it costs.

 

 

 

[wgscott]

 

It would be kind of cool to combine my two most stupidly expensive hobbies.

 

[DigiPete]

That is simply an abomination standing in the way of the perfect sound of a Steinway Lyngdorf Model D.

 

The only system that has ever tricked people from Steinway into thinking they were listening to a real Steinway Grand Piano Model D and not a recording.

 

Shame on him!

 

[ccclapp]

Pete, I'm impressed!

 

"This could be a Pulse Width Modulation (PWM) system.

The switching devices are either fully on or fully off, so no power is wasted and the efficiency approaches 100%.

A hefty low-pass filter would probably be needed to be in series with the output in order to prevent the high level of high-frequency switching noise from contaminating the neighborhood, and to reconstruct the analog waveform."...

 

...Your knowledge base goes WAY deeper than mine. I'm just a lowly real estate developer, who likes technology And good audio.

 

Now back to friendly banter...

 

""Where do you get your kicks, that is the question:"...

 

"The system should take up to DXD and DSD in the perfect world.

No reason why it is should no be doable.""...

 

But does it? that's my point. Why the obsession with integrated solutions, because by definition, if you care, there will be a weakness in the sole-solution, which does not exist in a component solution. Anyway, that is ot of this thread and just a user preference. As you said: liking to tinker vs liking to just have it work. Both are valid and neither is intrinsically " better".

 

...sorry to keep asking, but since the OP asked about the best location for the DAC, I ask again: what is a digital amp and is da conversion involved. I gather the answer is: a digital amp differs from a normal amp in that the digital amp has an integrated DAC, ( correct me if I'm wrong) which simply means it is a " normal" amp with a DAC right next door. If that is what we are discussing, please confirm. That being the case, the difference is ONLY a question of distance from DAC to amp. If so, is that meaningful enough for this debate/ banter? Because I don't have the background some of you may have, I don't understand the importance of this. In layman's terms, please clarify, as this was the question first posed in this thread.

 

It is great to have links to products and (truly interesting and well informed) bios on important figures, but what is the significance on sound quality, other than distance between DAC. I don't mean to beat a dead horse, but I'm not understanding.

 

Ps: Dear OP; if I'm taking this thread in a different direction than you intended, please say. This question of digital amps and their relevance would make an interesting dedicated thread, if you prefer.

 

 

 

 

[ccclapp]

"It would be kind of cool to combine my two most stupidly expensive hobbies."...

 

...ah, a fellow Ichthyologist, at last! Yes one of my highlights was when, after injecting my planted aquarium with co2 from a re-purposed scuba tank, exposing it to ultra-high halogen lights and mixing my own fertilizer made mostly from possum and nitrogen...I got my plants to "pearl" ie generate so much oxygen, that you you could watch the bubbles "pearl" / release from their leaves and rise to the surface, like champagne bubbles in a flute.

 

It's a little like searching for audio-nirvana

 

[audiventory]

I like idea of using full digital way (read audio data -> decode -> split channels -> dac+amp+speaker). DAC+amp+speaker as single device.

 

Integration of dac, amplifier and speakes allow (theoretically) make qualitative conditioning of this components by manufacturer (with pro measure gears). Troubles of model's DAC/AMP/SPEAKER selection no more. Conditioning of equipment with listening room is need only.

 

Resolving of cable's trouble also(using wireless connections).

 

[DigiPete]

The digital amp or Power DAC is a DAC in it self.

The difference between a DAC and a power amp is only the power of the output.

 

The difference between the real digital amp and the traditional class D amp lies in the input signal and how much is done to it:

 

Class D amp:

 

Digital signal -> D/A converter -> analogue signal -> A/D-ish conversion -> power electronics generating a PWM output -> smoothing/filtering

 

Digital amp:

 

Digital signal -> D/D conditioning -> power electronics generating a PWM output -> smoothing/filtering

 

Both generates a square wave signal with constant amplitude, but the precision is better on the digital amp because of less conversions.

 

Pulse Width Modulation of a sine could look like this:

 

 

 

Curtesy of Wikipedia

 

The PWM is driven by a clock that switches the signal on at constant intervals, the time it stays on is determined by the digital signal.

This is the pink curve.

 

The original analogue source is shown above.

This is the red curve

 

The result of smoothing out the blue curve should ideally be very close to the red curve.

It works if the sampling frequency is sufficiently high, not like it is shown here.

 

The D/D conditioning can be converting DSD (1 bit) or PCM (16-32 bit) into say a 4-8 bit signal.

 

Common (potential) traits of digital amps:

 

- High energy efficiency

- High slew rates

- Low cost

- Small constructions

 

This is a crude explanation, and I'm sure we'll see other implementations in the time to come.