Sometimes a passive crossover is just stupid...

[gberchin]

Please don't be like that, when you know very well what he meant.

No, as a matter of fact I don't. It is possible to provide the same DC supply from batteries (for a while), without any AC connection. The statement was provably false.

 

[NTK]

In the pro-audio world there is the Dante network, which connects devices via ethernet cables. There's also consumer products out there that do ethernet over power (ie through the electrical network already in your walls). So really we just need a company to blend the 2 products together, and then 1 cable really will do everything

Smart IP - Genelec.com

The AV professional’s dream – a flexible, easy-to-install family of premium-sound-quality, PoE active loudspeakers and subwoofers that receive audio, power and management all via a single CAT cable.

www.genelec.com

 

[SIY]

Yet hum and noise still exist on the DC outputs.

At vanishingly low levels, feeding circuits with high PSR. Non-issue for anything engineered.

Edit: here's the PS output for one of the DACs I use. Worst noise spike is half a microvolt and source impedance under 10 milliohm. Why do things the difficult, expensive, and bulkier way? Engineering would seem to be a much better path...

 

[gberchin]

Engineering would seem to be a much better path.

Always. But engineering is so often constrained by finance. (Rhetorical): For every well-engineered design, how many are not? The point is that an AC-to-DC power supply can be well-executed. But that's not the only possible solution. A DC-only design solves some of the problems intrinsically. A DC-only design introduces some new problems of its own. Variety is the spice of life. YMMV. Baskin-Robbins has 31 flavors of ice cream; there has to be a reason for that.

 

[SIY]

But engineering is so often constrained by finance.

You're making it sound like getting a quiet and stable DC supply is an expensive or difficult task.

It isn't.

If you want to play with batteries for the fun of it, great (I do the same with vacuum tubes) but there are literally zero advantages to it and a mass of disadvantages.

 

[gberchin]

If you want to play with batteries for the fun of it, great (I do the same with vacuum tubes)

Exactly.

there are literally zero advantages to it and a mass of disadvantages.

One person's disadvantage is another person's advantage, and vice-versa. It all depends upon what is important to each. Given the rat's nest of wiring in my multichannel, multiamplified system, reducing the number of cables, or eliminating them altogether, would make me very happy.

 

[neRok]

Smart IP - Genelec.com

The AV professional’s dream – a flexible, easy-to-install family of premium-sound-quality, PoE active loudspeakers and subwoofers that receive audio, power and management all via a single CAT cable.

www.genelec.com

Half way there...

 

[Waxx]

Power supplies can be made without noise comming from them, it's not even difficult to do. But a lot of snakeoil views make that a lot of amps are made with wrong psu's. Some tube amp freaks insist on a tube based linear psu, that is noisy. And many still swear with linear psu's while a good SMPS is often a way better id, even for high voltage designs like tube amps (Manley Labs did it, and many diy'ers also).

You can make those old coloured designs with clean psu's, be it tubes, class A or colouring class AB. But the market does not want that, they see SMPS as inferior because of older designs that were not on point yet. And low noise linear psu's also exist, but they will also modulate like an SMPS due to the voltage (and sometimes current) regulation circuits in it.

Batteries do work, but are very inpractical for hifi i think. But the many boomboxes and BT (smart) speakers show that it can be done. But for stationairy speakers, there is no practical benefit when the amp has a good power supply and when a cable is connected all the time, the batteries are just an extra cost and complexity that can go wrong.

 

[kyuu]

But the many boomboxes and BT (smart) speakers show that it can be done.

Ha, for some reason that didn't even occur to me. What he wants already exists. Just get a bunch of portable bluetooth speakers and enjoy the dulcet tones of your pure DC!

 

[solderdude]

Sometimes a passive crossover is just stupid...​

One can conclude that in most cases a passive crossover isn't stupid.

But sometimes people are so hardheaded that no argument can stop them.

Yep ... especially in the 'audio world'

 

[MaxwellsEq]

Every person who has ever fought 60 Hz hum from a ground loop can provide that evidence.

Ground loops are nothing to do with noise entering the gain stages via the AC to DC converter in the power supply section.

Every competent electronic engineer knows about PSRR (Power Supply Rejection Ratio). I seem to recall it being discussed in the first few weeks of my degree course. Competent EEs also know how to build power supplies that minimise the amount of noise exiting it. ASR is full of devices with mains noise below -100dB. These days you would have to be incompetent not to get to -80dB.

Power supply rejection ratio - Wikipedia

en.wikipedia.org

 

[Ktacos]

The amount of times I've loaded up vcad to come up with a passive crossover for a speaker only to realize that I really don't want to bother is quite high. I do wish there some more options for configurable DSP plate amps that were cheaper than what's out there now. The cheap ones seem to have high noise and distortion and the ones that don't are pretty expensive.

 

[mhardy6647]

You mean, like every half-proper PSU solves all these problems, and has been for what, 50 years?

More like 90 years.

 

[Chris A]

Um, unless you're planning to use the speakers somewhere that electricity isn't readily available, what's the purpose of putting batteries in it?

You might consider that Mr. Berchin may be implying that this doesn't have to be Bluetooth...which we all have probably heard has problems in congested living areas.

And using low power DC to resupply batteries at each loudspeaker (like a laptop recharges its battery only periodically) is a way to further reduce noise. The elimination of long loudspeaker wires is one key way to eliminate noise, especially when considering the interior of a loudspeaker cabinet can easily be made into a Faraday cage with something like an 802.11 mounted outside of the cage, piping only digital signals into the internal DSP crossover unit with efficient class D amplifier modules providing power to the individual drivers.

YMMV.

Chris

 

[gberchin]

The problems of powerline hum and noise, ground loops, etc., admittedly can be solved with existing technology. In practice, they often are not, since so much effort is still devoted to eliminating them. But my main motivation for DC power and wireless data has simply been ignored throughout this discussion: I have a nightmarish number of cables in my large system, a number that I want to reduce or eliminate. High PSRR and balanced connections will contribute nothing toward that goal.

Oh, and note that I said nothing about WiFi or Bluetooth. There is no reason to constrain potential solutions to existing off-the-shelf technology.

 

[gnarly]

Hahaha... fun, funny thread.
We all have our audio-pursuit show stoppers.
Passive crossovers are one of them for me....they are a simply a hit to sound quality on all but the simplest of two-way speakers. Proven fact, imo.

Another show stopper for me would be battery powered amps.
I don't care if this did provide some small marginal SQ improvement.
The last thing I want is a bunch more damn batteries to have to go around replacing. They do have a limited life, ya know.

 

[Waxx]

Yep ... especially in the 'audio world'

On both sides btw, it's like most people can't understand that the best way is case depending. The best example is the post above.

JBL manage to make top ranking speakers with passive crossovers, and so does Revel and Kef. They measure in the same league as top ranking active designs from Genelec, Neumann and co. Both, when done right, can be top, and both when done wrong can be absolute horrible. That is a fact that is data based (check the review list).

 

[gnarly]

On both sides btw, it's like most people can't understand that the best way is case depending. The best example is the post above.

JBL manage to make top ranking speakers with passive crossovers, and so does Revel and Kef. They measure in the same league as top ranking active designs from Genelec, Neumann and co. Both, when done right, can be top, and both when done wrong can be absolute horrible. That is a fact that is data based (check the review list).

well, I stated my 'case depending' application for a passive....the simplest of two-ways.

I strongly disagree when it comes to potential SQ on 3-ways and up..
Even the manufactures listed above extoll the virtues of active over passive.

Take KEF as an example. Member @LionIT is playing with taking his passive R3's active.
Look at this nice generous reply he received from @ davidbosch at KEF (I really admire such forthright info...KEF just made a fan of me)

Kef R3 META, digital crossover?

Hi all, I am an audio enthusiast and I really like to experiment with my system to seek an increasingly engaging but also technically more perfect experience. It's a bit like my hobby, let's say. I currently own KEF R3 Meta and two amplifiers, a Hypex NC252MP and a Neurochrome Modulus 86 (old...

www.audiosciencereview.com

For those who don't want to read the post, here's a quote pulled from it...(suggest to read the whole thing for full context)
"Finally, if you're going digital, go all the way and completely delete the passive crossovers. Passive crossovers both add distortion and dissipate power, so you can have a better speaker and happier amps with a digital crossover. You'll need more amps but it's probably the only way in which this project is worth it in my opinion. Hope this helps."

And please show me a Neumann 3-way that isn't tri-amped. (Maybe they make one, but I haven't seen it.)

Or how about the first sentence in Genelec's Key Technologies paqe:
"For over 40 years Genelec has been guided by a single idea – to make perfect active monitors that deliver neutral and accurate sound in every kind of acoustical environment."

Hey, I know the passive vs active thing re sound quality, gets debated to death. Like about every dang thing in audio I guess...

 

[Waxx]

Both styles have their quality for me, and i did design, build and use both styles, depending on the setup and it's goal. There is a place for both i think, and you should choose what fits you best. I even made mixed breeds also, where the top is passive and the sub is crossed active.

No need to blame the other side for something. A passive crossed Revel is equal good as an active Genelec or a Neumann (I never claimed they were passive btw). Just choose what fits you and know why.

 

[Ktacos]

Passive fits if you just wanna run one wire to a speaker and don't care too much about things being perfect. However once you hear an active speaker with very well aligned and integrated drivers it's hard to go back.

Great response from KEF in that other thread, accurate, informative, and transparent. Makes me laugh at companies like Harbeth that are basically afraid to intro their active options due to fear of upsetting their customer base.