Active Monitors: Digital or Analog crossover?

[AudioStudies]

Do you prefer digital or analog crossovers in active monitors? Why?

 

[daftcombo]

I would be interested in a list of monitors with digital crossovers to begin with. I'm not sure there are that many.

 

[q3cpma]

Digital simply allows for more but costs more, can have a bad implementation, needs an ADC stage or a digital input and is more complex (with probable effects on reliability).

 

[AudioStudies]

Does a pair of active monitors equipped with DSP automatically imply that the crossover is done in the digital domain? Also, does it seem like powered monitors don't offer a digital input option as often as they used to?

 

[Speedskater]

While a skilled engineer can design a good loudspeaker with either a analog or digital crossover. The digital one has a lot more powerful tools in the toolbox. For a new design, digital is the way to go.

 

[AudioStudies]

I see a lot of high performance DACs reviewed in these pages of ASR. If one selects a great DAC, I would think surely that the overall system performance could be limited by ADC and DAC within powered monitors following the great DAC in the signal chain.

 

[sergeauckland]

Digital without doubt.

1) DSP based crossovers can have much steeper slopes than is practical for analogue.
2) Much more easily adjustable without any compromise on performance
3) Including EQ, both parametric and graphic is easy, and usually included.
4) Often can export or import settings from software like REW.
5) Can hold several sets of settings for different circumstances.
6) Much more repeatable, down to 0.1dB is trivial.
7) Can apply time correction for different driver positions much more easily than analogue filters.

I can't think of a single circumstance where an analogue filter would be preferable.

S

 

[AudioStudies]

While a skilled engineer can design a good loudspeaker with either a analog or digital crossover. The digital one has a lot more powerful tools in the toolbox. For a new design, digital is the way to go.

Can this thought then make the case for having all active monitors equipped with digital inputs, and obviate the need for stand alone DACs in systems?

 

[AudioStudies]

Digital without doubt.

1) DSP based crossovers can have much steeper slopes than is practical for analogue.
2) Much more easily adjustable without any compromise on performance
3) Including EQ, both parametric and graphic is easy, and usually included.
4) Often can export or import settings from software like REW.
5) Can hold several sets of settings for different circumstances.
6) Much more repeatable, down to 0.1dB is trivial.
7) Can apply time correction for different driver positions much more easily than analogue filters.

I can't think of a single circumstance where an analogue filter would be preferable.

S

So then, is the reason we have stand alone DACs earlier in the chain than the powered monitors, just so manufacturers can make more money? Why not just have all powered monitors equipped with digital inputs? And why would anyone want to push the performance envelope with a stand alone DAC, if the signal will just be run through powered monitors anyway?

 

[sergeauckland]

Does a pair of active monitors equipped with DSP automatically imply that the crossover is done in the digital domain? Also, does it seem like powered monitors don't offer a digital input option as often as they used to?

I can't see any reason why the crossover wouldn't be done by the DSP. Once the audio is in the digital domain crossovers are just maths.

S

 

[sergeauckland]

So then, is the reason we have stand alone DACs earlier in the chain than the powered monitors, just so manufacturers can make more money? Why not just have all powered monitors equipped with digital inputs? And why would anyone want to push the performance envelope with a stand alone DAC, if the signal will just be run through powered monitors anyway?

I don't have standalone DACs, I just run the analogue sources into my loudspeakers' ADC.
I've never seen the point of external DACs anyway.

S

 

[AudioStudies]

analogue sources

Do you mean like vinyl and tape decks, or do you mean analog outs from CD player via a preamp to the powered monitors?

 

[sergeauckland]

Do you mean like vinyl and tape decks, or do you mean analog outs from CD player via a preamp to the powered monitors?

Both. My turntables, CD player and SBT all go through an analogue preamp for source selection and volume control, then goes to the 'speakers through the ADC in the crossover/equaliser.

S.

 

[AudioStudies]

Both. My turntables, CD player and SBT all go through an analogue preamp for source selection and volume control, then goes to the 'speakers through the ADC in the crossover/equaliser.

S.

Curious why you don't go with all digital sources? Your analog sources are being converted in the powered monitors anyway.

 

[AudioStudies]

I can't see any reason why the crossover wouldn't be done by the DSP. Once the audio is in the digital domain crossovers are just maths.

S

I think so too, so if a speaker is equipped with DSP, I just assume the crossover is digital.

 

[sergeauckland]

Curious why you don't go with all digital sources? Your analog sources are being converted in the powered monitors anyway.

I have to have source selection, signal routing and volume control and that's a lot easier to do in the analogue domain, then just do one conversion to digital in the ADC driving the 'speakers. The alternative is to use a separate ADC for the turntables then select just between digital sources, but that still leaves volume control, which can either be done in DSP, needing some sort of processor, or 6 way analogue after the crossover and before the power amps. Doing it in a conventional analogue preamp before one ADC is just a lot simpler. I'm not at all bothered by going digital to analogue to digital to analogue on my digital players as all my material is 16 bit and the converters are 24 bit, and a few extra conversions are so what.

S

 

[AnalogSteph]

Does a pair of active monitors equipped with DSP automatically imply that the crossover is done in the digital domain?

Often but not always. The JBL 104, for example, uses DSP but features passive crossovers - one speaker of the pair is in fact completely passive.

This I guess came about because they may be using the same one-chip wonder with ADC, DSP and two Class D power amps that also powers the LSR305 and the like, but just one for the pair instead of one per speaker.

 

[ng411s4]

As other people have said, implementing crossovers (and other facilities) in the digital domain has overwhelming advantages. I suppose one reason for considering active speakers with analog crossovers (implemented with op amps) might be serviceability. The Yamaha HS series uses analog methods and a service manual is available for it. I could imagine fixing a failed Yamaha HS (maybe) ... but something with a digital crossover ... not really! (Well, maybe it could be done if the fault was the "right sort").

I think it is a good question why digital inputs to active monitors are not the dominant way of doing things these days. If the loudspeakers use digital processing, and people are using purely digital sources, this would seem to be the way to go to me. For people with analog sources (FM tuners, turntables, tape machines), there must be an ADC somewhere, of course. But for music servers, streamers and optical disk players, a completely digital path would be possible.

Back in the 1990s, I believed the "future" for audio was (and should be) as digital as possible --- from immediately after microphone pre-amps to just before the power amps that drove loudspeaker transducers. In the late 1990s (when I felt I had enough spare money), I "invested" in what I thought would be my "end game" system, trying to follow the above "all digital" path as far as possible. The only company I knew of at the time that had chosen this direction was Meridian, so I bought their DSP 5000 loudspeakers and source components (which supplied digital S/PDIF to the
loudspeakers, and had ADCs to cope with analog sources). Meridian gear then wasn't as incredibly expensive as it is today, BTW. This didn't work as perfectly as I had hoped ... but I kept the loudspeakers for nearly 18 years, so it didn't work too badly either!

I really expected that by the early 21st Century, this type of "all digital" (as far as possible) system would be dominant. But I was wrong (as I often am!).

 

[AnalogSteph]

As other people have said, implementing crossovers (and other facilities) in the digital domain has overwhelming advantages. I suppose one reason for considering active speakers with analog crossovers (implemented with op amps) might be serviceability. The Yamaha HS series uses analog methods and a service manual is available for it. I could imagine fixing a failed Yamaha HS (maybe) ... but something with a digital crossover ... not really! (Well, maybe it could be done if the fault was the "right sort").

I think it is a good question why digital inputs to active monitors are not the dominant way of doing things these days.

Developer skill set and development budget. Analog monitors require:
* Speaker design
* Analog electronic design

If you want the same with DSP crossover, you'll need:
* Speaker design
* Analog and mixed-signal electronic design
* DSP programming

You might still find an analog guru who can design electronics and speakers, but those who can also do the programming are likely to be few and far between, so chances are you'll have to hire one more guy. I like my analog stuff, but I'm definitely not a natural-born coder.

A fair few passive speakers are essentially one-man jobs. The more complexity you add, the bigger the development team gets.

 

[audiopile]

Ng411s4 went where I have come to a few decades ahead of me. Here's what i run : pair of Meridian DSP-5000 speakers (one SPDIF input coming from the pass thru on a Benchmark DAC-3HGC -the second from a Mytek ADC that has a XLR switcher feeding it that allows me to switch between three turntables/preamps), into the Benchmark goes the output of another Mytek ADC which accepts the tape output of a old Linn Kolector preamp that is used as a analog switcher, my last SPDIF input on the Benchmark takes the digital output from a recently acquired Parks Audio Puffin -this is currently dedicated to whatever cart I'm using in a Technics SL-1210 mk2. This works for me.
Back to OP's question. The Meridian DSP-5000 I have been using for the last year and a half are at least 20 years old - how effective do I think they are ? I sold off speakers that were current models purchased new that year plus about half a dozen power amps of various sorts/models -these old n obsolete Meridians are just plain "right" to my old nun handles. BTW- I bought six DSP-5000's and a sub (which I will likely never use) for less than half the cost of the new speakers I had just bought. So-spare speakers in hand if/when the current pair fails.
Why'd I do this ? Because at one of the last Chicago CES shows (93?) I walked into the Meridian suite and was blown away: A classical piece was on -as I stood there a giant dynamic sweep started and this system went from solo instrument to the whole orchestra going to work -it was very detailed and amazingly loud and really ,really clean -nothing sounded on the edge of distorting. I described it as Khorn dynamics without the honkin and ringin . Looked at the price and lost interest for the next 25 or 30 years. I think digi speakers with DSP crossovers work .