passive/powered?

[Cool John]

which monitors are more accurate? passive (needs separate amp) or powered (biamped)?

ive heard conflicting views, and wanted to know what info you all had to offer

thanks

 

[subtractor]

I'd say it would depend on what kind of active monitors vs. what amp - passive monitor combo you might be considering.
I personally prefer active. That way you know that the speakers and amps inside have been matched to suit each other. Otherwise, there are infinite variations of sound, slight as they may be, between any given monitors and amps.

 

[Cool John]

Otherwise, there are infinite variations of sound, slight as they may be, between any given monitors and amps.

thats the logic i was using -- too many variables to know if its 100% accurate or not

the powered monitors im looking at is either Mackie 824's, or possibly Event 6's (although i doubt i would get those, i was scared away from event after finding out how poor the bass was on the 20/20's!)

passive- id probably go with Tannoy Reveals

 

[subtractor]

Those are both good ones. Tex says the "blue sky's" are supposed to be the shit though. You might check those out too. And they are a 3 piece with a sub, so bass won't be an issue.

 

[Henri Devill]

Those are both good ones. Tex says the "blue sky's" are supposed to be the shit though. You might check those out too. And they are a 3 piece with a sub, so bass won't be an issue.

I really like the BlueSky's also..If I was gonna go to different monitors,those would be in the runnin' for sure!My take on it is if you don't already have some nice amps..Go active..Look at it this way..Our boxes cost $600.00{Paradigm's ref.20's} our amps cost about $700.00 for the 6.5 speaks. and for the domes I think it was about 500.per{monoblocks..used} one for eact tweet...My partener already owned the amps..If he didn't already have those amps..$2300.00 Dammit.. we could have been into A.D.A.M's
.The cool thing about the Sky's the are only $1300.00 or so..


Don

 

[Recording Engineer]

I just wanted to point-out that "powered" does NOT mean "biamped" nor does "biamped" mean "powered".

"Powered" refers to an amp(s) mounted in/on the speaker enclosure. "Biamped" refers to two seperate amps powering the two drivers sperately in a 2-way speaker system.

Of course, a "powered" monitor CAN happen to be "biamped" as well, but it doesn't necessarily mean it actually is.

Then there's the issue of "passive" and "active". Traditionally, in circuit design, a circuit that requires power is refered to as "active" and a circuit that does not is refered to as "passive".
But in reference to speaker systems, "passive" refers to when the signal is amplified before a crossover network and "active" refers to when the signal passes through a crossover network before the resulting signal(s) is ampified.

Of course, a "biamped" 2-way system CAN happen to be "active" as well, but it doesn't necessarily mean it actually is.

One can easily see how a biamped passive 2-way system would, as a general statement, be more efficient than a single amplifier passive 2-way system.

Now if it is an active biamped 2-way system that we've got, as a general statement, it is usually significantly much more efficient than both the single amplifier passive 2-way system and biamped passive 2-way system.

Anyone know why, as a general statement, "active" is much more efficient than "passive"? I'll come-back later and explain why if no one has figured it out... But it's pretty straight-forward... Think with commonsense... I think everyone will figure it out with ease.

 

[alfalfa]

I agree you cant generalise and say active is better than passive or vice versa. I like passives because there is more flexibility when upgrading (eg you can upgrade your speakers without having to get a new amp) and you can use multiple speakers with the same amp. There are also many more choices with regards to speakers and amps as you also have accurate hifi products to choose from. Some also argue that the best speaker designers are not necessarily the best amplifier designers (I wont get into that one).

Another big factor is that I am unaware of any time and phase accurate active speakers (excluding the few single driver designs). In that respect passive is more 'accurate' because at least you can get time/phase coherent passive speakers. Accuracy in the time domain is an overlooked aspect of speaker design. An example of a speaker that is accurate in both the time/phase and frequency domains is here:
http://www.earthwks.com/ns/monitors.html

 

[BlueSky]

There are some definite benefits to powered monitors - here are just a few from my point of view...

1 No insertion-loss due to passive components - passive crossover components can reduce efficiency by 6dB or more. This means you will need much more power to get the same equivalent output with a passive speaker design.

2 Much more flexibility, with regard to EQ and phase compensation, allowing for flatter response and better off axis response.

3 Amplifiers can be designed to exactly match the drivers - no guess work for the end user.

With regard to "phase accurate" / "time-aligned" monitors -

1 Any speaker that is ported (or uses a passive radiator) can not be 100% phase accurate. This is because a port is a resonator, which means it takes "X" amount of time to start and "X" amount of time to stop resonating. This "X" variable can change with level and frequency.

2 A 2-way system, that does not have the drivers mounted in a coaxial arrangement, will only be time correct when the distance between the acoustic center of both drivers, is equidistant from your ears. If the driver arrangement is vertical, the time-alignment will change as you move off axis vertically.

3 "time-alignment" or "phase accuracy" has nothing to do with powered or passive speakers. It can be done physically, by placing the drivers in time alignment, with active electronics / DSP, or a combination of those 2.

General comments -

1 All speakers, and when I say all, I mean - all manufacturers, all designs, all types, at any price - are a compromise. There is no such thing as the "perfect" no compromise speaker system.

2 The single biggest factor in how a speaker system sounds and performs, is your room. If you can, it is always a good idea to acoustically treat the room. I would also do some research on boundary / speaker interaction, so that you understand how placement affects performance. Lots of good books on these subjects - and you can usually do the treatment yourself, for relatively little money.

Cheers!

 

[Kryogh]

wow, good info, once again..

Interesting stuff here. I bought the System One a few months ago, and I'm still trying different position for the satellites and the sub. I think I change their position at least 20 times!

Looks like I found new positions that are more pleasant each time. So I'm confused about this. But I obviously enjoy these monitors a lot more than my old ones

 

[alfalfa]

Any speaker that is ported (or uses a passive radiator) can not be 100% phase accurate.

IMHO better 90% (or whatever actual% it may be) than not even attempting for any kind of time/phase accuracy. At a minimum, the critical midrange and the highs will be phase accurate with one another. I would argue a speaker can be described as accurate only if the sound wave produced by it bears a close resemblance to the electrical wave/signal that was input to it. Only time and phase accurate speakers can do this. It is a suprising fact to most people that the waveform generated by most speakers (ie non phase coherent designs) do not look at all like the original electrical waveform. Obviously other people have differing views on what accuracy means and that is fair enough.

A 2-way system, that does not have the drivers mounted in a coaxial arrangement, will only be time correct when the distance between the acoustic center of both drivers, is equidistant from your ears. If the driver arrangement is vertical, the time-alignment will change as you move off axis vertically.

Agreed - I pointed out this issue in the concentric speaker thread being discussed in this forum (perhaps you could contribute some of your experience to that discussion). Vertically arranged time/phase coherent designs have to be optimised for a certain listening height. If you plan conducting your critical listening at a number of significantly different vertical heights then you had better go with a coaxial design.

"time-alignment" or "phase accuracy" has nothing to do with powered or passive speakers. It can be done physically, by placing the drivers in time alignment, with active electronics / DSP, or a combination of those 2.

Agreed - the point I made (I thought quite clearly if you reread my post) was that as far as I was aware there are currently no commercially available active speakers that are time and phase accurate. Therefore one has no choice but to go the passive speaker route if they want time and phase accuracy.

Thanks for the rest of the informative points in your post. I agree there is no perfect speaker and they are all compromises. People shouldnt get caught up in misleading stereotypes (eg all active speakers are better than passives speakers or vice versa) and look at the specific products in question and their own situation/needs, when purchasing speakers.

 

[BlueSky]

Agreed - the point I made (I thought quite clearly if you reread my post) was that as far as I was aware there are currently no commercially available active speakers that are time and phase accurate. Therefore one has no choice but to go the passive speaker route if they want time and phase accuracy.

Let me first say, that I am not trying to argue with you - but please explain how a monitor using passive components is in any way more or less likely to induce phase shift in a signal, as compared to a powered monitor with an active cross-over? (I would argue that it is actually more likely to end with an udesirable result when using a passive design.)


One more thing, please list any speaker with perfect phase and time response? It doesn't exist - speakers are not 100% linear devices...

 

[alfalfa]

You seem to be misunderstanding what I am trying to say. There is no reason why you cant build a time and phase accurate active speaker. I am saying that I do not know of any that are currently commercially available for me to buy. The only time and phase accurate speakers I am aware of utilise a passive design eg Thiel, Vandersteen, Meadowlark, Earthworks, Dunlavy, Quad electrostatics. They make speakers that are considered time and phase accurate (no one ever said 100% perfectly accurate - as you and I both agree there is no perfect speaker). Their step response measurements indicate time and phase coherence.

EDIT: before I forget, I better mention Aussie manufacturers that make time and phase accurate speakers too. VAF, Duntech and Sonique are three that I know of.

 

[BlueSky]

You seem to be misunderstanding what I am trying to say. There is no reason why you cant build a time and phase accurate active speaker. I am saying that I do not know of any that are currently commercially available for me to buy. The only time and phase accurate speakers I am aware of utilise a passive design eg Thiel, Vandersteen, Meadowlark, Earthworks, Dunlavy, Quad electrostatics. They make speakers that are considered time and phase accurate (no one ever said 100% perfectly accurate - as you and I both agree there is no perfect speaker). Their step response measurements indicate time and phase coherence.

I can tell you that our monitoring systems exhibit very good time and phase response, even down at low frequencies, but I can not speak for others. Although we currently don't have any impulse or step response data on our website, I will try to have our engineering department provide some data soon and uploaded so that it can be viewed.

I better go to bed now...

 

[alfalfa]

No problems bluesky, have a good night. I am keen to learn about any time and phase accurate active speaker designs that may be out there that I am not aware of (perhaps yours ).

 

[subtractor]

I can tell you that our monitoring systems exhibit very good time and phase response, even down at low frequencies, but I can not speak for others. Although we currently don't have any impulse or step response data on our website, I will try to have our engineering department provide some data soon and uploaded so that it can be viewed.

I better go to bed now...

What's your name?

 

[BlueSky]

What's your name?

Pascal Sijen

 

[alfalfa]

I just took a look around the blue sky website. I would say it is very unlikely that the blue sky sat 6.5 is time and phase coherent given the crossover used and the vertical baffle (tweeter is not stepped back as would be needed to achieve time/phase coherency). Anyway lets wait and see what the engineering dept of blue sky says and what the step response looks like.

 

[BlueSky]

I just took a look around the blue sky website. I would say it is very unlikely that the blue sky sat 6.5 is time and phase coherent given the crossover used and the vertical baffle (tweeter is not stepped back as would be needed to achieve time/phase coherency). Anyway lets wait and see what the engineering dept of blue sky says and what the step response looks like.

To some extent this is true, however, you also must try to correlate this one characteristic with subjective evaluation and also understand the effects of the listing environment / speaker placement.

Since a majority of our users will have the speakers higher than "on-axis" when monitoring (due the use a mixing console and other stuff that the monitor usually has to clear), the time/phase relationship will change, as mentioned previously. Additionally, acoustic factors in the room will also take their toll, to make this one characteristic less important. So when I say "good" that is our definition and maybe not yours. I would say that our experience, and our users experience, would seem to agree that our design works.

If you take a standard 2-way (non-concentric) out of the lab and into the field, do a lot of measurements, you will see that having "perfect" time alignment in the vertical plane (which will be defined as a very tight window) is not a good real world indicator of speaker performance or subjective quality.


...

 

[alfalfa]

If you take a standard 2-way (non-concentric) out of the lab and into the field, do a lot of measurements, you will see that having "perfect" time alignment in the vertical plane (which will be defined as a very tight window) is not a good real world indicator of speaker performance or subjective quality

Are you saying that 2way non concentric time/phase coherent speakers are not practical because of the restricted vertical listening height? Or are you saying that time and phase accuracy is not a good indicator of speaker performance or subjective quality.

If it is the former then I feel it is a separate topic from what we are discussing.

If it is the latter then we will have to agree to disagree. I feel time and phase accuracy is important to speaker performance and subjective quality but that is just my opinion. Your opinion that it is not important is equally valid

With regards to the original topic of speaker accuracy, my definition of an accurate speaker includes accuracy in both frequency and time/phase domains. Your definition of speaker accuracy does not include time/phase accuracy which is fair enough. Again we will have to agree to disagree.

In conclusion:
Am I right in my understanding that your speakers are not time and phase coherent?
Is my original statement that all the commercially available time and phase coherent speakers, utilise passive designs valid?

 

[BlueSky]

In conclusion:
Am I right in my understanding that your speakers are not time and phase coherent?
Is my original statement that all the commercially available time and phase coherent speakers, utilise passive designs valid?

They may not meet your ideal definition on axis, but I would say that they are good compromise, considering that in practical use, time alignment and phase coherence, at a specific on axis point, doesn't necessarily translate to "good sound". Please understand, that we do take all of these factors into account. This was my point when mentioning that you are always trading one thing for another, when it comes to speaker design.

I can not answer your second question, but I just wanted to point out there is no reason why there could not be a bi-amplified version of a speaker that meets your design criteria for phase / time alignment.

I think we have totally hijacked this thread, but it was nice talking to you about this - feel free to contact me directly if you want to discuss this further.

FYI - we do have a paper on our website about the tools we use to design our products - you may be interested in it... http://www.abluesky.com/m/p/bs80031a.pdf

CHEERS!