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Is there a reason more of you aren't running active? - Page 2

post #31 of 112
Quote:
Originally Posted by imagic View Post

I'm all active up front. It's the most worthwhile upgrade there is.

Why would you say it is that worthwhile? The reason I'm asking is because I was considering going active and have been shopping for amps. I will need a 3 way amp so I'm looking at the Digmoda DDC552 or DDC1055.

What are good quiet amps to use while running active? I've been looking at plate amps as they will be silent and have auto turn on. What other amps would be good to use for this that have XO's and EQ built in and are at least quiet? Rack mount would be acceptable but not as desirable as plate mount for my application.
post #32 of 112
I wish I had time for the long answer. The short answer is that I could not resist the dark side of the force.

The medium-length answer: Flexibility. I love tweaking the slope and crossover points. It's super-easy to time-align drivers. With active, you can store crossovers as presets and switch between them. I feel like hardware crossovers are akin to photography using film, and active is like the leap to digital photography with all the benefits that come with it. I'm in no position to suggest amps. I use Crown XTi amps and their built-in DSP but that's not going going to be the right solution for most people.

Quote:
Originally Posted by tsloms View Post

Why would you say it is that worthwhile? The reason I'm asking is because I was considering going active and have been shopping for amps. I will need a 3 way amp so I'm looking at the Digmoda DDC552 or DDC1055.

What are good quiet amps to use while running active? I've been looking at plate amps as they will be silent and have auto turn on. What other amps would be good to use for this that have XO's and EQ built in and are at least quiet? Rack mount would be acceptable but not as desirable as plate mount for my application.
post #33 of 112
Quote:
Originally Posted by MKtheater View Post

I am fully active on all channels. I use so called high quality amps(5 channels) with the DCX. Awesome!
You removed the crossovers on all the DR250's and DR200's? confused.gif
post #34 of 112
I kind of took the easy path to an active dsp based system. The fine engineers at Harman did all the work. Since I have the JBL cinema speakers, I was able to buy amps with the presets for my speakers. Now the cost. Normally these amps sell for $900 each, so $2700 to go active on the LCRs. I found them B-stock for $400 ea. So for me, cost really was the issue since the complexity is moot.
post #35 of 112
From a speaker design standpoint it is sure much nicer to design an active loudspeaker than it is a passive. You gain several degrees of freedom in what you can do with the response and you can make low frequency changes that are not possible with a passive network.

It can cost progressively more but not much considering the inexpensive high-quality amplifier choices available these days. Passive networks are not cheap with large inductors & caps so when I look at the BOM in a comparable design the parts cost isn't much different based upon just the PCB. If you use a chassis for the amp/crossover that can get expensive.

Most HT equipment is designed around passive set-ups. I wish more of them were preamp only set-ups that would output a balanced line-out only. Active loudspeaker designs have so many advantages that in a high-dollar theater there is no good reason not to design that way. Cost is the only reason not to design active loudspeakers.
post #36 of 112
Quote:
Originally Posted by Kevin Haskins View Post

From a speaker design standpoint it is sure much nicer to design an active loudspeaker than it is a passive. You gain several degrees of freedom in what you can do with the response and you can make low frequency changes that are not possible with a passive network.

It can cost progressively more but not much considering the inexpensive high-quality amplifier choices available these days. Passive networks are not cheap with large inductors & caps so when I look at the BOM in a comparable design the parts cost isn't much different based upon just the PCB. If you use a chassis for the amp/crossover that can get expensive.

Most HT equipment is designed around passive set-ups. I wish more of them were preamp only set-ups that would output a balanced line-out only. Active loudspeaker designs have so many advantages that in a high-dollar theater there is no good reason not to design that way. Cost is the only reason not to design active loudspeakers.

Right on.

The cost factor becomes bigger when you have a finished crossover design that someone else designed for you... assuming you don't have any desire to tweak it much. If you are just constructing and assembling vs. designing, passive can be much cheaper if you want it to be.

Perceived cost and real costs can converge quickly if you start going toward premium parts and amplifiers for passive solutions, or if you have to factor in the parts and time purchased in the design phase if you really want to polish out the result. If you are designing your own, I can't see a reason not to go with something like a MiniDSP, DCX-2496 or similar over the passive route other than cost of the amplifiers. With cheap multi-channel amplifiers it can be much more feasible than in the past. Also remember you often can get much greater efficiency in sections of the design than with a passive design, requiring lower power amplifiers than a passive design.

What I've often recommended to those who want to experiment with customized, more ambitious options is to find a capable mid-tweeter solution you can EQ as you like and go active for the midbass section. Crossover below 500Hz can be progressively tricky to execute passively while maintaining a desirable load impedance and smooth response. It's accomplished and adjusted to any frequency in a few clicks of the mouse in an active system.

Paraphrasing how Tom Danley likes to boil it down: "Each bump you fix in a passive crossover requires three parts. Actively it's a few clicks of the mouse." Finally, any narrow notches in a passive crossover vary with component tolerances, while an active crossover is the same every time you punch in the same numbers.

Both approaches have merit, both have benefits.
post #37 of 112
If you don't understand how to design a passive speaker, you probably don't understand how to design an active speaker. Although it is easier. But if you don't know how and want to build a kit or something, just ask the designer for the active settings and they'll probably have them.

Personally, I love using my minidsp and doing active. But I usually always go to passive in the end for simplicity. Unless I'm crossing below about 600hz then active is really the only way to do it well. The extra amps, rack space, wires, setup, etc aren't worth the little tiny bit of gains. Also, in not sure this will fly with many on these boards, and I'm not even convinced this is a problem myself, but the ADC - DAC that occurs may lower fidelity.
post #38 of 112
I have no clue how to build a passive crossover, nor do I care to. If someone has an electronics background and knows how to solder then more power to them. A properly designed passive crossover is something to be proud of. If you are computer-proficient but clumsy with tools (like I am) then active crossovers are better. I think Mark Seaton's post says it all. Depends on your skills and your needs and your budget, I suppose.
Quote:
Originally Posted by tuxedocivic View Post

If you don't understand how to design a passive speaker, you probably don't understand how to design an active speaker. Although it is easier. But if you don't know how and want to build a kit or something, just ask the designer for the active settings and they'll probably have them.

Personally, I love using my minidsp and doing active. But I usually always go to passive in the end for simplicity. Unless I'm crossing below about 600hz then active is really the only way to do it well. The extra amps, rack space, wires, setup, etc aren't worth the little tiny bit of gains. Also, in not sure this will fly with many on these boards, and I'm not even convinced this is a problem myself, but the ADC - DAC that occurs may lower fidelity.

Edited by imagic - 2/18/13 at 1:39pm
post #39 of 112
Sorry to be blunt, but I don't think you know how to design a proper active cross over, unless I'm missing something in your posts. You proper measurements including time information just like any passive design. It's not a click, enter, play experience. Seaton wasn't saying it is.
post #40 of 112
That's not what I was saying either, it took me a lot of time to get my speakers straight. What knowledge I do not possess, I can acquire thanks to the internet. You know that. It really is not rocket science.
Quote:
Originally Posted by tuxedocivic View Post

Sorry to be blunt, but I don't think you know how to design a proper active cross over, unless I'm missing something in your posts. You proper measurements including time information just like any passive design. It's not a click, enter, play experience. Seaton wasn't saying it is.

Edited by imagic - 2/18/13 at 10:33am
post #41 of 112
Quote:
Originally Posted by A9X-308 View Post

I'm assuming that most people have an AVR in system or have a learning remote like a Harmony and use macros to turn on. So when the AVR goes on, 12V trigger goes on and drives a realy or relays to turn on the amps for the multi amping. If no 12V trigger, then a simple button or switch manually done could do the same. For $20 more you can even get them to sequence on/off with a microcontroller.

My system is a lot more complicated than this but to use it you would need to know how to work a Harmony One remote, that it takes about 40 secs to power up from cold, where the IR sensor is and that you use the integrated keyboard/trackball to make control the HTPC where movies and music are stored. All other functions are on th H1.

Automation is great, and the Harmony can solve the multi remote issue if triggers and relays are not ideal, the problem is for a daily used system, what happens when someone hits the wrong button and then they call you to say, the tv doesn't work or there is no sound while your traveling for business or at work. I guess my point is that for a dedicated theater a complicated system with many components is fine, but if your main media center is used by other people, simple is better since the problem usually arises from the user, not the system. Any way my rant is more on the pros and cons of complicated setups vs simple ones for the user but it depends on the situation / use of the system. If i had a dedicated theater I would bi amp, but for daily watching of television in my living room, i think its overkill and not worth it to me. I'm fine with passive crossovers and amps that have plenty of headroom to properly reproduce transients without clipping or compression.
post #42 of 112
I made an assumption. Sorry it was rude.

My point is though, soldering has nothing to do with passive cross over design. It's about acoustics and so is active design. Personally I didn't learn cross over design by using google. Although possibly you could with enough time. I learned the fundamentals of acoustics in university and learned how to measure from a book and online and how to use simulation software online. I designed my first little 2-way a few years ago after a few attempts the wrong way and it took me since I started that pursuit back in 1999. I'm not very good yet. But it took me a long time to even get here. And i couldnt have done it without the internet, but i couldnt have done it with the internet alone either. I don't take it trivially which is why it annoys me when someone slaps a dcx on some big buck drivers and thinks they've created a masterpiece. It doesn't work that way, and neither does passive, even if you can solder.
post #43 of 112
Quote:
Originally Posted by tuxedocivic View Post

I made an assumption. Sorry it was rude.

My point is though, soldering has nothing to do with passive cross over design. It's about acoustics and so is active design. Personally I didn't learn cross over design by using google. Although possibly you could with enough time. I learned the fundamentals of acoustics in university and learned how to measure from a book and online and how to use simulation software online. I designed my first little 2-way a few years ago after a few attempts the wrong way and it took me since I started that pursuit back in 1999. I'm not very good yet. But it took me a long time to even get here. And i couldnt have done it without the internet, but i couldnt have done it with the internet alone either. I don't take it trivially which is why it annoys me when someone slaps a dcx on some big buck drivers and thinks they've created a masterpiece. It doesn't work that way, and neither does passive, even if you can solder.

Understood and agreed to a point...

My point was that if someone wants to start learning the design side of a loudspeaker, particularly the crossover, it is much easier to execute and test concepts and intents with an active crossover than with passive. Active execution requires understanding of filter response shapes, driver interaction and acoustic measurement. Once measuring, and adding filters to the chain, the learning curve can accelerate quickly. By contrast, passive filter design requires much greater knowledge of filter topology and the very complex interaction with the real impedance of a driver. I would argue this is equally if not harder a topic to grasp than an active system, especially if someone has never taken a course in circuit analysis. If you want to get really tricky and detailed with the frequency response, a horn can be the most difficult in this manner by far; requiring some topologies and techniques which are much less common with conventional dome and cone mid-tweeter designs.
post #44 of 112
Interesting points just made.
Additional consideration is that an active xover is not designed per se but implemented.
Passive components ( post amplification ) have to be designed for the power level that will be applied. More power bigger parts.
As the frequency goes down and/or power handling needs go up - the passive parts intrinsically get larger ( and more costly ) .
The properties and limitations of parts themselves become issues as does quality and manufacture tolerance. Coils have DCR and power handling issues that have to be considered ( such as saturation and hysteresis ) .
A passive system often has to include additional parts because it is on a shared circuit ( such as impedance flattening ) - In an active system the load is isolated/dedicated - no compound load or interaction.
In the early 70's active systems were far less common but active filters were used as "rumble filter" w turntables ( had one wink.gif ).
Advances in technology have today made amps cheaper and active crossover components widely available.
Edited by WVSyd - 2/18/13 at 12:11pm
post #45 of 112
Thread Starter 
Quote:
Originally Posted by Mark Seaton View Post

Understood and agreed to a point...

My point was that if someone wants to start learning the design side of a loudspeaker, particularly the crossover, it is much easier to execute and test concepts and intents with an active crossover than with passive.

That's a good point Mark. Experimentation in the active domain is much easier than passive; and mistakes are much easier to remedy (not withstanding driver damage). smile.gif
post #46 of 112
Quote:
Originally Posted by bass addict View Post

That's a good point Mark. Experimentation in the active domain is much easier than passive; and mistakes are much easier to remedy (not withstanding driver damage). smile.gif

Yeah and who is going to resolder 40-50 variations of passive components to really optimize a design? I have gone through hundreds of changes over the last 2 years with my settings. Thanks to electronic crossovers/DSP we can have the capability to say "Hmmm, I'd like to bump that area down 1dB at a time until I get it sounding/measuring juuuuust right." And if you can get presets, that's even better. Then you can have some settings for overly bright or thin sounding recordings to help tame those problems.

A brand that would do well electronically crossed over would B&W. Their higher end offerings use really very excellent drivers, but use passive crossovers with rather questionable target curves. I'd love to play with some after yanking out the built in passive.

Greg
post #47 of 112
Syd, active cross overs require design in the sense the designer needs to choose slope type, frequency, steepness, delay, level, eq, and that's not even talking about biquads. The design I'm talking about is not choosing components. What you're talking about in terms of power handling and such is about 0.01% of the design process.

Greg, that's what alligator clips are for.
post #48 of 112
I'm not sure how one derives a percentile figure in a design process ( particularly one that is DIY with it's diverse personal criteria ).
Experiences vary: but I've heard and observed ( Oscope wise ) coil saturation.
If a competent speaker manufacturer provides accurate measurements and better still provides tips on how their products are to be appropriately used: It's just a matter of purchasing a unit and applying settings.
Disclaimer: My background may differ so it's hard make a blanket statement on feasibilty for others. cool.gif
post #49 of 112
Quote:
Originally Posted by tuxedocivic View Post

Syd, active cross overs require design in the sense the designer needs to choose slope type, frequency, steepness, delay, level, eq, and that's not even talking about biquads. The design I'm talking about is not choosing components. What you're talking about in terms of power handling and such is about 0.01% of the design process.

Greg, that's what alligator clips are for.

True, but you're skimming over the aspect of getting a passive crossover to yield the frequency response you are after. This absolutely requires proper impedance measurements for the drivers *in the designed enclosures*. Even with the impedance data you still have to select the right circuit topology to achieve the response you may have in mind. Active systems allow those learning to focus on the acoustic measurements and target response curves.
post #50 of 112
Hey Mark,

I get that. I'm not denying active is easier than passive and that impedance adds another level of complexity. I'm trying to say to some here that active isn't a one click fix. Yes, active is much easier with the ability to add delay, use steep filters, ignore impedance, use high q eq, etc. Syd said active is an implementation. I disagree and believe it is a design process, similar to passive. An easier design process, sure.

Syd, I'm just throwing a number out there. Sure, coils saturate. Another reason to use active. I'm just not sure it's a very important consideration in the grand scheme of things.
post #51 of 112
Penngray learned like this iirc. He never did a passive afaik. Learned how to measure, started clicking to see what did what, and did a pretty good job in the end as far as I know. It is a good way to learn.
post #52 of 112
Quote:
Originally Posted by tuxedocivic View Post

Syd said active is an implementation. I disagree and believe it is a design process, similar to passive. An easier design process, sure.

Syd, I'm just throwing a number out there. Sure, coils saturate. Another reason to use active. I'm just not sure it's a very important consideration in the grand scheme of things.

To be clear: Many manufacturers build active crossover units - that aspect doesn't have to be designed. It does have to be implemented correctly.
Perhaps it's a difference in semantics here.
In terms of being able to buy a black box crossover : In the 70's armed with a book ( Like the Active OpAmp CookBook ) a dedicated Diyer might/did roll their own. That requires more skill than buying a xover for $100 today.
( In my case today - I could not fabricate a xover for less than I could purchase one due to scale of economics and mass production. )

I respectfully submit that we all have different schemes - perhaps my scheme is pushed more aggressively than most. But it certainly isn't near as demanding as someone like Burwen ( or some on this forum for that matter ).
Edited by WVSyd - 2/18/13 at 1:59pm
post #53 of 112
Ah, I see what you mean. Ya, we're probably arguing semantics. I consider implementing an active design to be hooking up the black box with RCA cables and a power supply and then punching in the settings. Just like implementing a passive to me is soldering up the parts according to a schematic. I consider the design to be measuring and determining the active settings according to design principles.

The part that gets confused with a lot of DIYers is that they think the black box will just make the mystery of a passive cross over go away and that a few mouse clicks will make good sound. Garbage in = garbage out.
post #54 of 112
Indeed
If speakers were perfect devices, then off the shelf cheap-o 2 and 3 ways passive crossovers would work better than they do in reality wink.gif.

One of my favorite books on Sound is Bob McCarthy's Sound Systems: Design and Optimization: Modern Techniques and Tools for Sound System Design and Alignment.
Granted it's primary audience is pro sound but it is a great book.
Edited by WVSyd - 2/18/13 at 2:51pm
post #55 of 112
Having an amp channel, DSP processor and in-wall wire to every driver, with an extra ADC-DAC conversion step.
We are talking huge money, heat, size, cost; domain specific knowledge, etc.
Then having to build/purchase the automation relays to power all that equipment up via an easy-button GUI.... or just living with it.
All just to gain some flexibility, headroom/efficiency and "potentially" SQ.
It's definitely not for everyone. It's no wonder why few do it (even without the automation).

Maybe one day AVRs will have more than just HP xo's and bass management; and actually have fifteen 8-way speakon connectors on the back and all that, until then I wouldn't hold your breath waiting for this to become the popular option; even within the DIY group.
post #56 of 112
Spin that whole thing around and push it all to the edge and things look much different. Fortunately or unfortunately I think what we will see in the future is the av receiver going away or becoming something entirety different from what we think of today.. and speakers all having some type of network interface for signal and possibly even power. The entire paradigm will change ultimately most speakers will end up fully active. Maybe not user adjustable though. Cheap efficient chip amps, only a matter of time till the network invades the speaker. Sonos is ahead of the curve on this but a good sign of where the world is going. I think we'll see some cool stuff to come and the speaker approach we know today will be entirely different. Just my simple view.
post #57 of 112
Good observation and I tend to agree. Networked, whether wired or wifi is the way things will end up. Traditional audio rigs full of esoteric gear will be looked at like the Amish.

Greg
post #58 of 112
Quote:
Originally Posted by BassThatHz View Post

Maybe one day AVRs will have more than just HP xo's and bass management; and actually have fifteen 8-way speakon connectors on the back and all that, until then I wouldn't hold your breath waiting for this to become the popular option; even within the DIY group.

It sure would be nice to be able to buy a new Yamaha/Onkyo/Pioneer/whatever 9 channel AVR and daisy chain another (older & cheaper since we are dreaming) 5-7-9 channel AVR to get to an "entry level" system up and running with two boxes and an HDMI (RS232?) cable or two between them. Properly spaced banana plugs would be fine smile.gif
post #59 of 112
Questions for Mark, Tux, and whoever else wants to chime in.

Where can a person find information on setting up an active crossover? What all is involved in setting the active filters? Where can a person learn about: slope type, frequency,steepness, delay, and level? (did I leave out any filter types?)

What are biquads?

I would love to see a sticky or two with some basic crossover knowledge explained for both passive and active crossovers. We just need someone who understands this stuff to spend some time typing it up. Or someone could possibly provide some links or book suggestions?
post #60 of 112
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