Active vs passive comparison

[davedotco]

The bolded part. I've noticed on several articles in Stereophile JA would criticize certain speakers that didn't have steep enough crossover attenuation and a driver is going into breakup mode just enough audible to cause coloration that may be interpreted as midrange detail, presence or when played at louder volumes as brightness and harshness.

I Have pointed this out on a number of occasions when people have suggested that a speaker is 'bright' and then blamed it on metal dome tweeters.

In fact it is the metal cone bass units that are more likely to be the cause, they might be nice and pistonic at lower frequencies but when they break up, they really let go.

 

[Vladimir]

The bolded part. I've noticed on several articles in Stereophile JA would criticize certain speakers that didn't have steep enough crossover attenuation and a driver is going into breakup mode just enough audible to cause coloration that may be interpreted as midrange detail, presence or when played at louder volumes as brightness and harshness.

I Have pointed this out on a number of occasions when people have suggested that a speaker is 'bright' and then blamed it on metal dome tweeters.

In fact it is the metal cone bass units that are more likely to be the cause, they might be nice and pistonic at lower frequencies but when they break up, they really let go.

Yup. My B&W CM1s had a big hole in the upper midrange to keep the drivers from having audible breakups. This would not be necessary if they didn't make the small midbass woofer work like mad with a large boost at 100Hz. But if they didn't do that, the speaker wouldn't sell in the showroom that well. Euphonic sound is appealing and I've bought several such speakers despite knowing they are not neutral sounding.

The crossover is just a single cap, inductor and resistor.

 

[matt49]

The reason better amplifiers sound better than less good amplifiers with passive speakers is that the less good amplifiers were not up to the job in the first place, something that should not be the case with active designs. I say 'should' as there are some really bad active speakers out there, much the same as regular hi-fi in fact.

Yes, should not. But is inadequate amplification only a problem in 'really bad' active speakers? One point that seems to come out of the Stereoplay ATC review is that the amp driving the woofer in the active version may not to be up to the job. Or at least that's one possible reason for the active version's higher LF distortion measurements.

 

[Ajani]

The reason better amplifiers sound better than less good amplifiers with passive speakers is that the less good amplifiers were not up to the job in the first place, something that should not be the case with active designs. I say 'should' as there are some really bad active speakers out there, much the same as regular hi-fi in fact.

Yes, should not. But is inadequate amplification only a problem in 'really bad' active speakers? One point that seems to come out of the Stereoplay ATC review is that the amp driving the woofer in the active version may not to be up to the job. Or at least that's one possible reason for the active version's higher LF distortion measurements.

No. I don't think we can take that from the review. The reviewer only noted less distortion when using a 20K pair of Ayre Monoblocks. Amps far more expensive than the whole active system. That's not a realistic comparison. When he used the more price appropriate Vincent amps, he prefered the active system.

 

[matt49]

Yes, should not. But is inadequate amplification only a problem in 'really bad' active speakers? One point that seems to come out of the Stereoplay ATC review is that the amp driving the woofer in the active version may not to be up to the job. Or at least that's one possible reason for the active version's higher LF distortion measurements.

No. I don't think we can take that from the review. The reviewer only noted less distortion when using a 20K pair of Ayre Monoblocks. Amps far more expensive than the whole active system. That's not a realistic comparison. When he used the more price appropriate Vincent amps, he prefered the active system.

The graph labelled 'Pegel- und Klirrverlauf' clearly shows steeply rising distortion for the active version at low frequencies. I grant my explanation for the distortion may be wrong (it's been suggested elsewhere that the active version may employ an EQ boost on the bass which causes the higher distortion), but the distortion's definitely there.

I don't care much what amps were used: the fact is the passive speaker, using the Ayre monoblocs, had lower LF distortion. This indicates that the amplification of the active version isn't ideally suited to drive the woofers; it can be improved on by going passive and using more expensive amplification.

 

[davedotco]

The reason better amplifiers sound better than less good amplifiers with passive speakers is that the less good amplifiers were not up to the job in the first place, something that should not be the case with active designs. I say 'should' as there are some really bad active speakers out there, much the same as regular hi-fi in fact.

Yes, should not. But is inadequate amplification only a problem in 'really bad' active speakers? One point that seems to come out of the Stereoplay ATC review is that the amp driving the woofer in the active version may not to be up to the job. Or at least that's one possible reason for the active version's higher LF distortion measurements.

I really do not think we can draw sensible conclusions from poor designs, they are just plain rubbish.

Simple plate amplifiers that are 'good enough' are relatively cheap and it requires a lot of money to improve on them, money that in a budget design can often be spent much better elswhere.

We have had this discussion inlength in the various 'How many watts' threads, but in affordable audio, many 'separates' amplifiers are not good enough if you expect or require them to do anything difficult. If you do not have such a requirement is is remarkable how compedent a decent budget amplifier can be.

 

[Vladimir]

The amp used is this one.

Amp Pack: [*]3-way active design.[*]ATC “Grounded Source Topology”.[*]350W Class AB total output.[*]4th order active crossovers with phase correction.[*]Soft limiting driver protection.[*]Convection cooled.[/list]

I count 8 output transistors, 2 bridge rectifiers and 60,000uF per module. Not exactly small. But Ayre MX-R have all that x2!

"Output Power: HF 50W , Mid 100W , LF 200W"

Something tells me those watts are in 4 ohms at least for the LF (not disclosed by ATC) and the woofers are sucking that amp dry. *scratch_one-s_head*

 

[Ajani]

Yes, should not. But is inadequate amplification only a problem in 'really bad' active speakers? One point that seems to come out of the Stereoplay ATC review is that the amp driving the woofer in the active version may not to be up to the job. Or at least that's one possible reason for the active version's higher LF distortion measurements.

No. I don't think we can take that from the review. The reviewer only noted less distortion when using a 20K pair of Ayre Monoblocks. Amps far more expensive than the whole active system. That's not a realistic comparison. When he used the more price appropriate Vincent amps, he prefered the active system.

The graph labelled 'Pegel- und Klirrverlauf' clearly shows steeply rising distortion for the active version at low frequencies. I grant my explanation for the distortion may be wrong (it's been suggested elsewhere that the active version may employ an EQ boost on the bass which causes the higher distortion), but the distortion's definitely there.

I don't care much what amps were used: the fact is the passive speaker, using the Ayre monoblocs, had lower LF distortion. This indicates that the amplification of the active version isn't ideally suited to drive the woofers; it can be improved on by going passive and using more expensive amplification.

Perhaps we are debating semantics here, but I wouldn't expect the amp used in an active speaker to be the absolute best amp possible for the driver. I have a very nice sounding pair of M-Audio BX5a actives. While I'm sure the amps have been tailored (to some degree) to suit the drivers, the whole setup only costs 300 USD. So by default I know that better amps are available, if I'm willing to spend more money.

So clearly if you are willing to upgrade then passives present a more appealing option, however in my case I just wanted the best sound for the tiny bit of cash I was spending. So I couldn't find a passive setup for 300 USD that was remotely appealing.

So back to the ATCs - when using the passive versions and the Vincent amps, the reviewer prefered the active setup for similar money. So if you really like the ATC speakers and have no desire to upgrade, then you get the active version. If you know that in a few years you'll probably want to change amps, tweak etc then go passive.

 

[matt49]

So back to the ATCs - when using the passive versions and the Vincent amps, the reviewer prefered the active setup for similar money. So if you really like the ATC speakers and have no desire to upgrade, then you get the active version. If you know that in a few years you'll probably want to change amps, tweak etc then go passive.

This seems to be the case. If it were my money, I'd go for the actives.

 

[Ajani]

Another option if you like upgrading is to get actives with external amplification such as the JBL M2s:

http://www.jblpro.com/www/products/recording-broadcast/m2/m2-master-reference-monitor#.VnrL8xUrLIU

 

[steve_1979]

The bolded part. I've noticed on several articles in Stereophile JA would criticize certain speakers that didn't have steep enough crossover attenuation and a driver is going into breakup mode just enough audible to cause coloration that may be interpreted as midrange detail, presence or when played at louder volumes as brightness and harshness.

As well as causing harsh sounding distortion due to cone breakup it also reduces the dynamic range too as the drivers are still wasting energy trying to play audio in the frequencies that aren't suitable rather for them than only playing the audio frequencies that they can comfortably reproduce.

So the steeper 4th order crossovers that are common in actives not only reduce cone break up distortion but they also increase the potential dynamic range of the speaker. In other words they still sound clear even when played at higher volumes.

 

[steve_1979]

It's pointless dissecting your various posts as you ask. You have written many long posts yet you keep completely failing to grasp the basic concepts of what has been discussed here. Until you can understand the 3 points made below all that further discussion on this subject will achieve is wasted time and fustration for us both as we go around in circles getting nowhere. Also it's Christmas and I have much more interesting things to do with my time than spend the next few days arguing with internet strangers about a subject that I don't even care much about.

1. Why steeper crossovers are better than shallow crossovers (in both 2 and 3 way speakers) because it reduces the the amount of audio the drivers are playing outside of the range they can handle.

2. Why having a crossover between the amplifier and driver progressively removes control of the amplifier the closer to the crossover frequency it gets in order to stop the full range signal from the amplifier from reaching a driver. Like I said in my first post this is like the amplifier in a passive system is trying to push the driver in and out using a spring instead of having a a tight grip on the movement of the driver.

3. Why point 2 above also means that the amplifier has to work twice as hard in a passive system as the amplifiers do in an active system.

 

[lindsayt]

1. Why steeper crossovers are better than shallow crossovers (in both 2 and 3 way speakers) because it reduces the the amount of audio the drivers are playing outside of the range they can handle.

I agree that this true - for some - maybe even most modern speakers.

So, can you tell me: why not use 64th order crossovers instead of 1st, 2nd, 3rd, 4th, or 8th order crossovers?

Especially if ultimate sound quality is the objective, regardless of cost?

 

[DocG]

1. Why steeper crossovers are better than shallow crossovers (in both 2 and 3 way speakers) because it reduces the the amount of audio the drivers are playing outside of the range they can handle.

I agree that this true - for some - maybe even most modern speakers.

So, can you tell me: why not use 64th order crossovers instead of 1st, 2nd, 3rd, 4th, or 8th order crossovers?

Especially if ultimate sound quality is the objective, regardless of cost?

The Avantgarde Zero 1 has a filter steepness of up to 100 dB/octave.

The DEQX crossover does up to 300 dB per octave. Not sure what "order" that is though...

 

[lindsayt]

2. Why having a crossover between the amplifier and driver progressively removes control of the amplifier the closer to the crossover frequency it gets in order to stop the full range signal from the amplifier from reaching a driver. Like I said in my first post this is like the amplifier in a passive system is trying to push the driver in and out using a spring instead of having a a tight grip on the movement of

Steve, looking up the Wikipedia entry for "Spring (device)" it says:

"A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. There are a large number of spring designs; in everyday usage the term often refers to coil springs."

Can you explain to me how a first order passive crossover stores any electrical energy, that would instead have gone directly to the speaker driver?

 

[lindsayt]

The Avantgarde Zero 1 has a filter steepness of up to 100 dB/octave.

The DEQX crossover does up to 300 dB per octave. Not sure what "order" that is though...

DocG, a 300 db per octave slope would make it a 50th order crossover.

 

[DocG]

The Avantgarde Zero 1 has a filter steepness of up to 100 dB/octave.

The DEQX crossover does up to 300 dB per octave. Not sure what "order" that is though...

DocG, a 300 db per octave slope would make it a 50th order crossover.

Aha, we're closing in on 64th order then! *drinks*

 

[lindsayt]

It's pointless dissecting your various posts as you ask. You have written many long posts yet you keep completely failing to grasp the basic concepts of what has been discussed here. Until you can understand the 3 points made below all that further discussion on this subject will achieve is wasted time and fustration for us both as we go around in circles getting nowhere. Also it's Christmas and I have much more interesting things to do with my time than spend the next few days arguing with internet strangers about a subject that I don't even care much about.

1. Why steeper crossovers are better than shallow crossovers (in both 2 and 3 way speakers) because it reduces the the amount of audio the drivers are playing outside of the range they can handle.

2. Why having a crossover between the amplifier and driver progressively removes control of the amplifier the closer to the crossover frequency it gets in order to stop the full range signal from the amplifier from reaching a driver. Like I said in my first post this is like the amplifier in a passive system is trying to push the driver in and out using a spring instead of having a a tight grip on the movement of the driver.

3. Why point 2 above also means that the amplifier has to work twice as hard in a passive system as the amplifiers do in an active system.

Steve, the thing that seems to be happening here in this thread is that you post something that is misleading.

I respond by saying why I think it is misleading, giving specfic examples, with technical information that anyone can verify. And then you're responses have not told me the following:

1 whether you have understood what I have written

2 whether you agree with anything that I have written

3 if you disagree with anything that I have written, you have not said why you disagree with anything specific that I have written.

So, as a prime example; you provided a quote where someone said about passives: "Damping is a miserly 300 times worse than with an active system". In the context of the way you provided that quote I was led to believe that you agreed with this. I then gave a specific example that showed that the difference in damping between a particular passive to active speaker system was 6.74 to 6.04 at the resonant frequency of 60 hz (where the lower figure is better from a damping point of view). And the difference rose to 10.14 to 6.04 at the non resonant frequency of 400hz.

Steve, do you now agree with me that it is totally misleading for anyone to say that damping is a miserly 300 times worse with a passive system than an active one?

If you don't agree with me, and you still think that passives have 300 times worse damping, what is this based on?

 

[jcbrum]

You don't need anything beyond about -70dB because so little energy remains it's completely inaudible.

Only the slope matters really.

Happy Christmas everyone.

JC

 

[Vladimir]

Disadvantages of a passive crossovers

1 ) Back EMF (electromotive force) goes back into the crossover, interferes with the input signal from the amplifier.

2 ) Passive crossovers buffers the amplifier from the drivers resulting in loss of damping, loss of direct amplifier control over the drivers.

3 ) Loading effects, inductors, magnetic coupling, larger Cs, and parameters less adjustable.

4 ) Passive network wastes power, lowers efficiency, requires higher wattage amplifier to compensate.

5 ) Differing impedance of various drivers and the resulting phase shifts from the crossovers present a difficult load for the amplifier, especially 1st order crossovers.

6 ) Crossover properties and accuracy varies with power and temperature resulting in shifting properties and inconsistent linear response.

7 ) Low order crossovers reduces phase & time shifts but introduces other issues. Greater frequency sharing between drivers, and higher strain on drivers due to wider bandwidth demands increases distortion, both THD and intermodulation, induces interference patterns, amplitude irregularities, driver resonances, cone breakup, and hampers off-axis response.

8 ) High power draw in a specific frequency range, usually the bass, may cause amplifier clipping and possible damage to the woofer, midrange, or most likely, the tweeter. The amp has to deal with the combined complex impedance load and power draw.

Advantages of passive crossovers

1 ) Plug & Play simplicity.

2 ) One amp, one cable, done.

Disadvantages of active crossovers

1 ) Residual noise from crossover, less of an issue for digital processors.

2 ) Greater susceptibility to EMI (electromagnetic interference), and RFI (radio frequency interference).

3 ) Multiple amps & cables, more complex setup.

Advantages of active crossovers

1 ) Direct control of each driver by its own amplifier.

2 ) Easier impedance load on the amp.

3 ) No loss of power or damping factor.

4 ) Reduced clipping. If clippings occurs, only one driver/amp is affected.

5 ) Crossover works at line level maintaining its design properties.

6 ) Each amp deals with only a specific bandwidth.

7 ) Reduced harmonic distortion.

8 ) Reduced intermodulation distortion.

 

[BigH]

Im late to this topic but the amp should ideally not be in the cabinet for simple acoustics reasons. So lets take the amps out the active speaker cabinet. Then the question is about crossover in the speaker vs 'crossover in the amp'. I doubt there is a clear winner there so I'd say that it resume with multiple amp vs single question. I think a single is better, a very good toroidal with precisely matched handpicked components for the circuit is just too expensive to do 4 or 6 times just for a pair of speakers. Good speaker builder and amp designer should not be the same team because its different skills. Separation leads to specialization. Not to mention that I can plug another amp and enjoy my speakers better. But I could also mimatch. Assuming I wont mismatch I believe that passive is better.

You have missed out several points. One the speaker maunfacturer does not know what amp will be used and also the amp. manufacturer does not know what speakers you will use. So yes there will be many mismatches. With active they do know the demands of each, therefore can tailor the amp. for each speaker, ie. you can have 200w for the bass/mid driver and 50w for the tweeters for instance. They will know how many Ohms also. I don't agree that active crossovers and passive are the same and many speakers use cheap crossovers. You can look at the PMC video about active and passive speakers, that will explain some of the advantages of active, they make both types. I have tried both from what I heard my active ones were better than the passive systems I heard costing upto 50% more, I'm sure you can find a perfect passive match but its not easy. Also the cost was/is lower for active and you don't need to buy any speaker cables, which is another factor, so no need to spend 100s on cables to get that night and day difference. You want to read this: http://www.enjoythemusic.com/magazine/manufacture/0403/

and this: http://sound.westhost.com/biamp-vs-passive.htm

I'm not saying everyone will prefer active but I think they should be auditioned when choosing a system.

But at least you should agree that the amp should not be in the cabinet to start the reasoning. Then you don't accept the second point that solving the frequency overlap of tweeter/woofer can be done equally well if the crossover is in the speaker rather then the amp. What's left is really a matter of having multiple amps but they are not tailored to the woofer in the way you think, it's a question of economy, if they put 100 watt on the tweater amp they will have to put resistance in the circuit because it needs less juice to play the same level. Having more amps brings a full set of problems. My m3-8 are tri amplified so by your theory they should best yours. They have 3 gain adjuster at the back making an awesome equalizer but the linearity of the volume is not perfect and I use calibration tool to verify. When you start to hear how a good amp affect sound you'll quickly agree that you can't afford 2 or 3 per speaker. Amps have to be isolated from vibration and cabinet should not be filled, even more so with electronics.

Yes maybe there is some logic the amps should not be in the cabimet. But they are not always, with active you site them outside anyway. As for the crossovers you make out the only difference between passive and active is the location, active and passive crossovers are not the same, no I DON@T accept your theory at all. As for amps yes they are tailored usually to the power requirements, mine have 200w for the drivers and 50w for the tweeters. As for your speakers they seem to be very budget studio monitors, all due respect but what are you goung to get for £250, with the dealer/tax man taking 50%, cabinets probably cost £50, does not leave much left for the rest?