Active vs passive comparison

[abacus]

Some of the posters in this thread need to get their high school physics books out, as the amount of twaddle being posted in this thread are quite frankly embarrassing. (With threads like this it is no wonder that Hi-Fi nuts are classed as a joke in the pro (And Real) world)

Bill

 

[matt49]

Just a few points by way of a tentative summary of the arguments so far:

1. if the detrimental effects of passive crossovers are always really so great, it seems they would have shown up in the measurements of the two ATC SCM50s reviewed in Stereoplay.

2. on the other hand, it may well be the case that the benefits of active operation are more noticeable in certain types of speakers, in particular smaller speakers with long-throw woofers, and this would explain a widely held view, viz. that active operation is a particular advantage at the budget end of the market.

3. it may be that the benefits of active operation are swamped by other kinds of consideration in speaker design (e.g. cabinet construction or driver type) and amplifier power/technology.

4. some expert opinion and the opinion of some manufacturers clearly backs active operation. As in all fields of commerce, one has to apply a measure of scepticism to what manufacturers say about their own products.

5. it's widely claimed that the use of active speakers in music production is evidence of their inherent superiority. On the other hand, the use of active speakers in the pro world may not be driven by SQ considerations alone, and by no means all pro speakers are active: there are passive speakers that sell in decent quantities in the pro world (e.g. Harbeth).

 

[matt49]

Some of the posters in this thread need to get their high school physics books out, as the amount of twaddle being posted in this thread are quite frankly embarrassing. (With threads like this it is no wonder that Hi-Fi nuts are classed as a joke in the pro (And Real) world)

Bill

Comments of this general kind are unhelpful. If you have an issue with a particular argument, please point it out; if you don't, it looks like you're just blustering.

 

[davedotco]

1 & 2) I feel the biggest issue with passive crossovers is the demands it makes on the amplifier, I am not at all sure how comparitive measurements of that could be done.

In some cases I think passive crossovers work very well, I am thinking of the 1st order types used in classic Sonus Faber and Epos models though it is important to realise that the drive units were of unusual quality in these examples, custom made in the Epos and special versions of already expensive drive units in the 'Fabers.

So I think the driver is very important, the better the driver and the more suited it is to the design, the simpler the crossover and the better the sound. (I have tested and compared 'simple' vs 'complex' crossover designs in the same speaker)

3) Not sure if that is relevant, better drive units and cabinets can be incorporated equally into passive or active designs, the differences between active and passive designs are still there.

4) Quite right, and some contributers to this and other fora have an agenda too, balanced views are hard to come by.

5) Again correct. Professional requirements place other factors much higher than hi-fi users, robustness and reliability most obviously, so no SQ is not the only driving factor here. The real difference is the different emphasis placed on certain aspects of a loudspeakers performance by a professional user and by a hi-fi user, this is most noticeable at the affordable end of the price spectrum.

 

[Vladimir]

The general conclusion of that article is that plate amps can be undersized for the application.

In my past 2 days of testing the little JBL LSR305s on a brief occassion I've pushed them to clipping with some major bass pounding tracks and it was amusing to me hearing only the bass bottoming out, yet the top end remaining perfectly clear. Of course I don't expect wonders from an amp the size of my pinkey fingernail.

How loud were you playing them and what size is the room? I've never really tested how loud my similarly sized active speakers can go, but at uncomfortably loud volumes in a 25x12ft room they've never lost their composure. And the bass sounds ridiculously impressive considering that the woofers are just 5 inches.

That's the problem with these. I played them so loud I have ringing in my ears second day now. At the moment I had no idea I was doing it since I wasn't hearing distortion at all where I would typically back off. Only on two occassions with some very congested bass heavy music. The midbass drivers produce a lot of thundering, tight and purrring bass, yet they barely move at all, just slightly wiggle. If there was clipping, it must have been the amp. I'm still suspicious if I was hearing distortion or the bass drivers were coupling because the desk was shaking, I could even feel it on the floor, despite all the foam and sand I used as dampening. Or it could have been just rubbish recordings on Tidal. I can't tell for certain.

As for the expected clear, dynamics, dry bass and analytical sound, I honestly am hearing smooth, very nonfatiguing sound and the bass is relentless but not boomy. Clarity appears only on certain recordings. On my B&W CM1s regardless what I played there was a hole in the upper midrange and some presence was missing. With these JBLs it feels very recording dependant. Some sound dull, some exciting, some have presence, some don't, some tracks have too much bass, it's sickening, and others lacking. Unfortunately I hear a lot of distortion on some music from Tidal and the loudness compression seems more obvious. I don't know if the streaming rate is dropping at times, or is it the watermark distortion or they just have low upsampled 128 mp3s or baddly ripped 320s... No idea. But it doesn't sound as good as my CDs and can't get as loud without distortion.

I'm not sure if these JBL LSR305s really are representative of how proper studio actives sound. Dry bass, brain piercing clarity on everything, fatiguing harsh brightness, excesive analytical sound... I get none of that. They just groove with the music and are very enjoyable to listen to, if not to look at.

Sorry for the mini review. Carry on.

 

[Vladimir]

Wow, Wikipedia openly promotes actives over passives and powered speakers.

Fidelity
The main benefit of active versus passive speakers is in the higher fidelity associated with active crossovers and multiple amplifiers, including less IMD, higher dynamic range and greater output power.[1] The amplifiers within the loudspeaker enclosure may be ideally matched to the individual drivers, eliminating the need for each amplifier channel to operate in the entire audio bandpass. Driver characteristics such as power handling and impedance may be matched to amplifier capabilities.[2] More specifically, active speakers have very short speaker cables inside the enclosure, so very little voltage and control is lost in long speaker cables with higher resistance.

An active speaker often incorporates equalization tailored to each driver's response in the enclosure.[14] This yields a flatter, more neutral sound. Limiting circuits (high-ratio audio compression circuits) can be incorporated to increase the likelihood of the driver surviving high-SPL use. Such limiters may be carefully matched to driver characteristics, resulting in a more dependable loudspeaker requiring less service. Distortion detection may be designed into the electronics to help determine the onset of protective limiting, reducing output distortion and eliminating clipping.[15]

 

[matt49]

That's the problem with these. I played them so loud I have ringing in my ears second day now. At the moment I had no idea I was doing it since I wasn't hearing distortion at all where I would typically back off.

Hey, be careful!

With these JBLs it feels very recording dependant. Some sound dull, some exciting, some have presence, some don't, some tracks have too much bass, it's sickening, and others lacking.

Is this dependent on the genre of music? Some genres do suffer from an overly generous use of bass. I guess they're designed to be listened to in cars with massive bass bins.

Or is there any chance this is a room problem?

I'm not sure if these JBL LSR305s really are representative of how proper studio actives sound. Dry bass, brain piercing clarity on everything, fatiguing harsh brightness, excesive analytical sound... I get none of that.

I don't buy in to the cliche about active monitors being overly dry or bright. What you're hearing from your JBLs is exactly what I'd expect to hear from small actives (and similar to how I'd describe my small Adams).

 

[Vladimir]

With these JBLs it feels very recording dependant. Some sound dull, some exciting, some have presence, some don't, some tracks have too much bass, it's sickening, and others lacking.

Is this dependent on the genre of music? Some genres do suffer from an overly generous use of bass. I guess they're designed to be listened to in cars with massive bass bins.

Very genre dependant, yes. Pop, rock and blues is mostly rubbish but contemporary jazz and classical sound sublime (except for that occassional watermark distortion that feels like adding vibrato or tremolo).

Or is there any chance this is a room problem?

I call it a desk problem. There are odd reflections I'm not used to with the typical hi-fi setup. Lower frequencies deffinitely have issues with this arangement.

 

[lindsayt]

So if someone uses large efficient speakers and makes them actives that would be the best speaker ever. But exception would be the sgnal going through active crossover issue you mention. Can you expand on that please?

Vladimir, good question.

Here is a circuit diagram for 1 channel of an active crossover for 3 way speakers:

Source: http://archive.siliconchip.com.au/cms/A_30278/article.html

If we follow the signal path through to the midrange output we see that it passes through quite a large number of resistors and capacitors. It also passes through 6 op amps!!!

In my passive system the signal from DAC chip to speaker drivers will pass through about the same number of op amps / transistors / valves / transformers as that!

So placing this active crossover in my system would approximately double the number of active amplification devices in my systems signal path!!!

 

[Ajani]

The problem with the whole shortest signal path, straight wire with gain and other myths is that by that logic the best sounding HiFi should be this:

Yet as far I know, no audiophiles are pushing for the return to the gramophone. Yet it is pure analog with no electrical nonsense to mess up the signal path.

 

[Vladimir]

The problem with the whole shortest signal path, straight wire with gain and other myths is that by that logic the best sounding HiFi should be this:

Yet as far I know, no audiophiles are pushing for the return to the gramophone. Yet it is pure analog with no electrical nonsense to mess up the signal path.

Actually i've heard that being said by people who collect them. The big ones can really go loud.

 

[Ajani]

The problem with the whole shortest signal path, straight wire with gain and other myths is that by that logic the best sounding HiFi should be this:

Yet as far I know, no audiophiles are pushing for the return to the gramophone. Yet it is pure analog with no electrical nonsense to mess up the signal path.

Actually i've heard that being said by people who collect them. The big ones can really go loud.

I shouldn't be surprised. I'm sure there are persons who want us all to go back to using horse drawn carriages instead of cars.

Are those persons audiophiles or just Gramophone collectors? Also, you have some really strange friends. *lol*

 

[matt49]

Ajani, that is a great big massive non-sequitor.

non sequitur

 

[Covenanter]

Ajani, that is a great big massive non-sequitor.

non sequitur

If you are going to correct spelling mistakes on this CB you are going to find no time to listen to music.

Chris

 

[matt49]

Ajani, that is a great big massive non-sequitor.

non sequitur

If you are going to correct spelling mistakes on this CB you are going to find no time to listen to music.

Chris

Chris, I only correct spelling mistakes in Latin.

 

[Vladimir]

Ajani, that is a great big massive non-sequitor.

The briefest of listening tests will show you that LP's played on a properly engineered turntable with a decent MC cartridge sound much more realistic than 78's played on a wind up gramophone.

Just as listening tests with a properly engineered passive system, especially one with a short and simple amplification signal path will show that adding an active crossover, like the example with the circuit diagram, introduces a certain amount of transistorised hash to the midrange. With the benefit being that the system will sound as if the amplifiers are having an easier time. How much of an easier time depends on how much of a hard time the speakers were giving the amps in the first place.

And Ajani, think about it. Do you really think that adding all those components, slap bang in the middle of the midrange signal path is going to have no adverse sonic effects whatsoever?

The electronic crossover in my little JBL actives is solved with a single digital chip, and so is the amplification. Over 80% of the board is occupied by the power supply (SMPS).

Are you cringing now? *biggrin*

Wait till you see that expensive Genelecs run on STK and cheap Samwha caps.

 

[Ajani]

Ajani, that is a great big massive non-sequitor.

Why? Because you say so? The entire purist argument you are so in love with is about simplicity improving sound. The Gramophone is a far simpler design than any SET/LP/speaker system you are in love with. Hence from a purist stand point, the Gramaphone must sound better than your prefered setup.

The briefest of listening tests will show you that LP's played on a properly engineered turntable with a decent MC cartridge sound much more realistic than 78's played on a wind up gramophone.

Just as listening tests with a properly engineered passive system, especially one with a short and simple amplification signal path will show that adding an active crossover, like the example with the circuit diagram, introduces a certain amount of transistorised hash to the midrange. With the benefit being that the system will sound as if the amplifiers are having an easier time. How much of an easier time depends on how much of a hard time the speakers were giving the amps in the first place.

There are many reasons to use passive speakers but you are probably the first person I've heard claim that passive crossovers are superior to active ones. and you back up your claims with the opinion of one unnamed passive manufacturer. So with all due respect, I don't consider that credible.

And Ajani, think about it. Do you really think that adding all those components, slap bang in the middle of the midrange signal path is going to have no adverse sonic effects whatsoever?

And linsayt, think about it. Apply that same question to adding electrical power, amplification tubes etc to a Gramophone to create your sytem. Do you expect that to have no adverse sonic effects whatsoever?

The reason for complexity is to solve specific problems in simpler designs. The issue is whether the added complexity solves more problems than it creates or vice versa. So just using a simpler design guarantees nothing.

 

[drummerman]

Use headphones. Active, no Xover, no room interaction and single point source (except balanced armature).

 

[drummerman]

Nevermind the STK, at least they use stock Seas drivers. Just look at the Yamaha thin stamped sheet metal woofers!

Actives must sound like absolute sh*t. No boutique components of any kind, just bottom of the bin stuff, worse than what Technics and Sherwood used in their low budget stuff 30 years ago. And soooo many cheap integrated components in the frail signal path... Just goes to show you that audiophiles do know better than studio pro's.

There's nothing worse than an ex-smoker ...

 

[Vladimir]

Nevermind the STK, at least they use stock Seas drivers. Just look at the Yamaha thin stamped sheet metal woofers!

Actives must sound like absolute sh*t. No boutique components of any kind, just bottom of the bin stuff, worse than what Technics and Sherwood used in their low budget stuff 30 years ago. They even saved on port tubes by hotgluing two of the same to form one port. And soooo many cheap integrated components in the frail signal path... Just goes to show you that audiophiles do know better than studio pro's or audio circuit designers.

 

[Ajani]

Use headphones. Active, no Xover, no room interaction and single point source (except balanced armature).

You could also use very large electrostats (that way you don't need a subwoofer for the bass).

 

[Vladimir]

What I lack in technical knowledge I compensate well in facetiousness. *i-m_so_happy*

 

[drummerman]

What I lack in technical knowledge I compensate well in facetiousness. *i-m_so_happy*

I had to google that

 

[Covenanter]

Wow, Wikipedia openly promotes actives over passives and powered speakers.

Fidelity

The main benefit of active versus passive speakers is in the higher fidelity associated with active crossovers and multiple amplifiers, including less IMD, higher dynamic range and greater output power.[1] The amplifiers within the loudspeaker enclosure may be ideally matched to the individual drivers, eliminating the need for each amplifier channel to operate in the entire audio bandpass. Driver characteristics such as power handling and impedance may be matched to amplifier capabilities.[2] More specifically, active speakers have very short speaker cables inside the enclosure, so very little voltage and control is lost in long speaker cables with higher resistance.

An active speaker often incorporates equalization tailored to each driver's response in the enclosure.[14] This yields a flatter, more neutral sound. Limiting circuits (high-ratio audio compression circuits) can be incorporated to increase the likelihood of the driver surviving high-SPL use. Such limiters may be carefully matched to driver characteristics, resulting in a more dependable loudspeaker requiring less service. Distortion detection may be designed into the electronics to help determine the onset of protective limiting, reducing output distortion and eliminating clipping.[15]

I don't think Wikipedia promotes anything! People post things there, which if not challenged remain in place. It's not a source of kosher information. (The referencing instructions for my MA course say "Never Wikipedia".) It can be a useful guide for pointing at kosher stuff though.

Personally I've never been convinced by the arguments that say actives are materially better than passives. I suspect the truth is that well-designed stuff will sound good and poorly-designed stuff will sound bad.

Chris

 

[Vladimir]

Wow, Wikipedia openly promotes actives over passives and powered speakers.

Fidelity

The main benefit of active versus passive speakers is in the higher fidelity associated with active crossovers and multiple amplifiers, including less IMD, higher dynamic range and greater output power.[1] The amplifiers within the loudspeaker enclosure may be ideally matched to the individual drivers, eliminating the need for each amplifier channel to operate in the entire audio bandpass. Driver characteristics such as power handling and impedance may be matched to amplifier capabilities.[2] More specifically, active speakers have very short speaker cables inside the enclosure, so very little voltage and control is lost in long speaker cables with higher resistance.

An active speaker often incorporates equalization tailored to each driver's response in the enclosure.[14] This yields a flatter, more neutral sound. Limiting circuits (high-ratio audio compression circuits) can be incorporated to increase the likelihood of the driver surviving high-SPL use. Such limiters may be carefully matched to driver characteristics, resulting in a more dependable loudspeaker requiring less service. Distortion detection may be designed into the electronics to help determine the onset of protective limiting, reducing output distortion and eliminating clipping.[15]

I don't think Wikipedia promotes anything! People post things there, which if not challenged remain in place. It's not a source of kosher information. (The referencing instructions for my MA course say "Never Wikipedia".) It can be a useful guide for pointing at kosher stuff though.

Personally I've never been convinced by the arguments that say actives are materially better than passives. I suspect the truth is that well-designed stuff will sound good and poorly-designed stuff will sound bad.

Chris

That is exactly the point I was trying to make to lindsayt. He is thinking on a component level (opamps bad, too many components bad), not thinking on a system level. Just like a dentist adding an expensive aftermarket air intake and oil filters to his car to improve it because he likes cars and reading about them.

I recommend the movie Moneyball on this topic.