Passive Speakers

[lindsayt]

you don't hang out in HDD forum Lind, do you?

Hi oldric_naubhoff

Or on the Forum with the greatest name ever :rofl:

All the best

Rick @ Musicraft

I don't like posting on forums where I'd feel like I'm always the away team in a football match, with referees and linesmen that were biased towards the home team.

I prefer playing on neutral grounds with neutral officials, which is why I'm happy to post on this forum.

 

[MUSICRAFT]

Hi lindsayt

Good to see you on here

All the best

Rick @ Musicraft

 

[oldric_naubhoff]

you don't hang out in HDD forum Lind, do you?

Hi oldric_naubhoff

Or on the Forum with the greatest name ever :rofl:

All the best

Rick @ Musicraft

I don't like posting on forums where I'd feel like I'm always the away team in a football match, with referees and linesmen that were biased towards the home team.

I prefer playing on neutral grounds with neutral officials, which is why I'm happy to post on this forum.

 

[oldric_naubhoff]

Having read so much recently about active speakers producing a more accurate sound why do some hifi enthusiasts continue to purchase/use passive speakers? I was thinking about buying some myself, having had little success tracking down the active speakers I wanted to buy originally. However, I am apprehensive about buying passive as so many now consider them less accurate and an inferior product. Should I be concerned?

Back on topic ... there are hybrid speakers that have passive mid-range drivers and tweeters but a powered bass driver all in the same cabinet ... like these http://www.goldenear.com/index.php/products/triton-towers.

and very good they are. I had a chance to experience them in action once last year. they made so good impression on me that I almost bought them. but in the end I decided not to buy another box speakers (however great) because I wanted to try out what planar speakers do well. so I ended up with Magnepans.

 

[alchemist 1]

Any good recommendations for high efficiency and good value passives Lindsay?

Knowing your penchant for huge vintage speakers ... any suggestions for something that might fit in a normal room and that don't look too baroque . I quite like the idea of Klipsh Heresy III but they are a bit pricey new????

what about these? although they would fit a normal barn but don't look too baroque. maybe rustic.

Ooooh, just think of the dusting !!! :O

 

[oldric_naubhoff]

Monitor Audio and Focal fall into this catagory nicely. And they don't lack bass either.

I think what Lindsayt regards as efficient speaker is anything around 100dB. MA and Focal with their 90dB efficiency thereabouts don't come even close. don't be fooled. 10dB difference around 90dB mark starts to make a huge difference in volume levels.

Are ther many domestic (home hi-fi speakers) go that high? My old Wharfedale E series was 96db, and they entertained the neighbourhood. The main problem I found was not a lack of bass, but how quickly they distorted. They were, however, designed to be used with valve or tube amps - back in those days the average wattage of a midrange tube amp was around 10-25 watts typically. With such low output they were well suited.

this kind of speakers would be the most domestically friendly high efficiency speakers I can think of

those are DeVore Orangutan O96. 96dB efficient. Audio Note makes similar speakers too.

 

[Anonymous]

Having read so much recently about active speakers producing a more accurate sound why do some hifi enthusiasts continue to purchase/use passive speakers? I was thinking about buying some myself, having had little success tracking down the active speakers I wanted to buy originally. However, I am apprehensive about buying passive as so many now consider them less accurate and an inferior product. Should I be concerned?

There are great sounding active and passive speakers, so I don't think you need to be too worried about the technology, just try to listen to a few very good examples of both. I would however say, that IMO, great sounding active speakers are generally cheaper than great sounding passives, as you'll obviously also need a suitably powerful amplifier for passive speakers, and they tend cost quite a bit of money.

On the flip side, you may also need a pre amplifier and DAC with some active speakers, which balances things up again. If you could, go to Bartletts Hifi where they stock a good range of active speakers, including the fabulous AVI ADM9Ts, which contain an in built preamp and DAC, I don't personally think they can be beaten for sound for Pound.

And I would also suggest giving Rick of Musicraft a call, as he stocks a very good range of passive speakers and some great quality active speakers, I found him extremely helpful and honest in the past. Take on board the advice you get, evaluate the sound of the different speakers, any perceived differences between the two technologies, the cost, and make your own informed decision.

 

[lindsayt]

this kind of speakers would be the most domestically friendly high efficiency speakers I can think of...

those are DeVore Orangutan O96. 96dB efficient. Audio Note makes similar speakers too.

Sometimes you need to be a bit watchful with efficiency specifications given by speaker manufacturers.

Audio Note claimed that their AN-E Lexus signature speakers were 98db's efficient. Stereophile measured them at 92.5 dbs efficiency! The Devore's look like medium sized traditional coned and domed speakers which suggests that independent efficiency measurements might make interesting reading.

 

[Ajani]

this kind of speakers would be the most domestically friendly high efficiency speakers I can think of...

those are DeVore Orangutan O96. 96dB efficient. Audio Note makes similar speakers too.

Sometimes you need to be a bit watchful with efficiency specifications given by speaker manufacturers.

Audio Note claimed that their AN-E Lexus signature speakers were 98db's efficient. Stereophile measured them at 92.5 dbs efficiency! The Devore's look like medium sized traditional coned and domed speakers which suggests that independent efficiency measurements might make interesting reading.

I was going to make a similar point. The AN-E is not the only high efficiency speaker to be tested and found to be well short of specifications. So you really have to be careful when buying speakers based on efficiency ratings.

 

[Exshopguy]

Usually the only way to get big efficiency on a speaker is to make it very large - smaller models that are well over 90dB efficiency generally sacrifice bass extension and tonal accuracy to do so. They tend to sound very dynamic and "live" as a positive. Lower sensitivity speakers transversely usually have better bass extension and tonal balance but need a lot more amp power for real dynamics. It's all a balancing act really and there's still no magic solution in Hi-Fi to get the best of both worlds.

 

[steve_1979]

I am apprehensive about buying passive as so many now consider them less accurate and an inferior product.

IMO the difference between actives and passives isn't all that huge and other factors such as the drivers and enclosure will make a bigger difference than the crossover. There are plenty of good and bad examples of both active and passive speakers around so I suggest that you have a listen to as many of both types as you can and make up your own mind which you prefer.

That said, I do think it's easy to hear a worthwhile improvement when you compare good quality active speakers to equally priced good quality passive speakers. The actives have a bit more clarity and better controlled bass. They also offer better value too.

Should I be concerned?

I wouldn't worry about it too much. There's plenty of great sounding speakers around (both active and passive). Just go with whatever sounds best to your own ears.

 

[byakuya83]

Thank you all for the helpful replies. I don't have time for auditions so will base my purchase on reviews, looks and features. At least now I have a larger range available as general consensus is that there's not a huge gulf in musicality between good active speakers and good passive speakers.

 

[steve_1979]

At least now I have a larger range available as general consensus is that there's not a huge gulf in musicality between good active speakers and good passive speakers.

While I agree that there isn't a huge gulf between them active speakers are still generally better than passives. If you go for good quality actives from the likes of Genelec or Dynaudio then you'll end up with a pair speakers that would (IMO) beat any passive speaker/amp combo for the same price.

I don't have time for auditions so will base my purchase on reviews, looks and features.

It really would be worth taking the time to audition speakers yourself if possible. But if you aren't able to then actives are a safer bet. With good quality actives at least you'll know that the speakers are paired with the right amplifiers. I wouldn't fancy trying to choose a good combination of amplifier and speaker based only on reviews .

 

[lindsayt]

...With good quality actives at least you'll know that the speakers are paired with the right amplifiers...

Except that there's a good chance that 3 way active speakers would sound better (and have less measured distortion at low to moderate volumes) with a good valve amp for the midrange.

 

[Anonymous]

The only teorical advantage of active loudspeakers over passive ones is that it's possible to design a customized amplifier circuit for a given set of speakers or vice-versa. However, there are more disadvantages than advantages, like lack of physical space and some serious technical issues, such as speakers electromagnetic field interference.

In fact, by adopting an external amplification system the designer has much more room to work: it's possible to design more sophisticated and powerful amplifiers as there's much more space to implement more complex circuits, and; heat dissipation and electromagnetic field effect are much more easier to be controled outside of the loudspeakers cabinets.

I prefer to believe the option of active speakers is for cost reduction sake. It's possible to save financial resources on cabinets.

 

[steve_1979]

The only teorical advantage of active loudspeakers over passive ones is that it's possible to design a customized amplifier circuit for a given set of speakers.

With all due respect to Audio Maniac this is just not true.

Using amps that are custom designed to work with individual drivers is only one of many reasons why active speakers are potentially better.

The passive crossover also adds a considerable abount of audiable distortion but an active crossover does not.

With an active crossover it's possible to use a steeper roll off slope which sounds better than a shallow roll off slope.

A passive crossover also effects the way in which an amplifier controls the movement of a driver. With a passive crossover in between the amp and the driver it's like trying to push the speaker cone in and out using a spring. But when the amp is connected directly to the driver it has a much more direct and effective control over the movement of the speaker cone.

 

[the record spot]

Having read so much recently about active speakers producing a more accurate sound why do some hifi enthusiasts continue to purchase/use passive speakers? I was thinking about buying some myself, having had little success tracking down the active speakers I wanted to buy originally. However, I am apprehensive about buying passive as so many now consider them less accurate and an inferior product. Should I be concerned?

This is the problem when you read blanket generalisations about supposed superiority. Not all actives are created equal (and hence not all will be better). A technical preference in terms of design benefits doesn't necessarily mean that this will suit your needs better.

I've heard many actives and many passive speakers. My current setup sounds great, really great - involving, well presented, I'm not missing out. The Genelec speakers, actives, which I've heard were also excellent. Likewise Yamaha's HS50s and HS80s. See also Roland's DS7. Others were a tad on the bright side, or just too flat - aimed at the producer's studio than the home.

It's horses for course, but don't buy into the perceived wisdom that's been peddled round here of late that simply because a speaker doesn't have onboard amps or DACs that suddenly makes them a poor product. It doesn't and they're not.

 

[hoopsontoast]

Having read so much recently about active speakers producing a more accurate sound why do some hifi enthusiasts continue to purchase/use passive speakers? I was thinking about buying some myself, having had little success tracking down the active speakers I wanted to buy originally. However, I am apprehensive about buying passive as so many now consider them less accurate and an inferior product. Should I be concerned?

I would not be concerned.

I have passive speakers, as they sound very good. I would not buy an 'active' speaker because it was active, it would have to be that it sounded good. I dont think you should pigeon hole speakers into being good/bad because they are active or not.

As with all things, and its been mentioned before, that you will get both very good and very bad implementations of both types of speaker.

My current speaker happens to be passive speakers, this is not because they are passive but they sound great, and there is not an active or passive model that would be better value. As it happens, my amp costs around 8 times more than the speakers, just to factor that in.

 

[lindsayt]

...The passive crossover also adds a considerable abount of audiable distortion but an active crossover does not.

With an active crossover it's possible to use a steeper roll off slope which sounds better than a shallow roll off slope.

A passive crossover also effects the way in which an amplifier controls the movement of a driver. With a passive crossover in between the amp and the driver it's like trying to push the speaker cone in and out using a spring. But when the amp is connected directly to the driver it has a much more direct and effective control over the movement of the speaker cone.

On what basis are you saying that the passive crossover adds a considerable amount of audible distortion? Have you or anyone else done a comprehensive set of measurements to measure the distortion of a variety of passive crossovers at all frequencies and power levels and signal shapes used when listening to domestic hi-fi systems?

It is quite simply not true that op amp based active cross don't introduce audible amounts of distortion. Find out which op amps are used in your active crossover and then look up the data sheets for that op amp. If they include THD+N versus power or voltage graphs you will see that distortion rises dramatically as voltage decreases. You will also see that distortion rises almost vertically at the onset of clipping. So what you get is a power zone where the op amp is not producing audible distortion. Outside of the op amps comfort zone you will get significant amounts of THD+N distortion. Music is based on a logarithmic power scale that will take the op amps in an active crossover outside of their comfort zone.

If the passive crossover is acting as a spring then this would manifest itself as worse transient response. And for sure for some passive amp and speaker combinations this can be heard as a lack of dynamic ease - where it sounds like the amps are being given a hard time because they are being given a hard time. Moving to active amplification with such combinations does help with the dynamic ease. But it's not just passive crossovers that create poor transient response / dynamic ease in speakers. Ports create poor transient response in the bass because you get a bass transient that produces noise off the front of the bass cone which is followed a tiny bit later by resonant noise coming out of the port from the energy coming off the rear of bass cone - creating bass bloom. Also you get poor transient response if the bass cones are too small for the frequency and volume. A small cone has to travel further than a large cone to produce the same volume of bass sound. The magnetic field in which the bass coil sits will not be uniform - creating non-linearity distortion. Also the cone surround will act as a big spring as you get larger and larger bass cone movement. Large cone movements also add doppler effects - which can upset the pitch stability of higher frequency instruments that mid-bass cones are asked to produce at the same time as bass transients.

Large cone movements also have the effect of turning the voice coil into an electrical generator resulting in the cone overshooting as it returns to its resting position. High damping factor (from low amplifier output impedance) will help to minimise / control this effect. This is therefore an area where active is better than passive due to the passive crossover adding to the impedance of the speaker to amp circuit and therefore decreasing the damping factor. This could be what you mean by the spring effect of passive crossovers? But if you have large bass cones and therefore small cone movements you will be minimising this electrical generating affect which will make damping factor less important.

A passive speaker with huge bass cones in a sealed box will produce better bass transient response than an active speaker with small cones in a ported box. To me it's absolutely crazy from a sound quality point of view to worry about the spring effect of passive crossovers when the designer has completely ignored the undesirable spring and distortion effects from using bass cones that are too small.

I can't think of any particular reason why a steeper roll off slope should sound better than a shallow one for all speakers. What happens when you have well matched and blended drive units where a 6 db slope sounds fine? What sonic advantage is there to be had from using a steeper slope with these speakers? I have speakers that were designed to use 6 db crossover slopes. When I actively bi-amped them I tried 6, 12, 18, 24 db slopes on my active crossovers. They sounded best with the 6 db slopes although to be honest we're talking about very subtle differences and I'd be happy to live with any slope. Where you have drive units that are not particularly well matched I can see advantages of steeper crossover slopes in order to avoid bumps in the frequency response. If you're worried about the different drive units being out of phase in the crossover region and the comb effects from the sound in this region coming from two different drivers then this will depend upon how far you sit from your speakers. If you are using them as nearfield monitors then this is important. As you sit further away from them it becomes less important.

I haven't even started discussing passive electrostatic speakers yet which work on different principles to coned and domed speakers resulting in certain technical and sonic advantages and disadvantages.

 

[byakuya83]

Having read so much recently about active speakers producing a more accurate sound why do some hifi enthusiasts continue to purchase/use passive speakers? I was thinking about buying some myself, having had little success tracking down the active speakers I wanted to buy originally. However, I am apprehensive about buying passive as so many now consider them less accurate and an inferior product. Should I be concerned?

I would not be concerned.

I have passive speakers, as they sound very good. I would not buy an 'active' speaker because it was active, it would have to be that it sounded good. I dont think you should pigeon hole speakers into being good/bad because they are active or not.

As with all things, and its been mentioned before, that you will get both very good and very bad implementations of both types of speaker.

My current speaker happens to be passive speakers, this is not because they are passive but they sound great, and there is not an active or passive model that would be better value. As it happens, my amp costs around 8 times more than the speakers, just to factor that in.

Thank you.

My purchase will not be simply based on whether active or passive. As you say, that's not the most important factor.

As for comment above that built in amplification will match what is required for the drivers, can the same be said for powered speakers? Or does the lack of an active crossover mean it's no different to passives with a separate amplifier?

 

[steve_1979]

On what basis are you saying that the passive crossover adds a considerable amount of audible distortion? Have you or anyone else done a comprehensive set of measurements to measure the distortion

Yes it has been measured many times and is well documented in hifi and speaker engineering text books.

Also here's a link to Martin Grinrod's findings on active and passive crossover distortion. [LINK REMOVED - house rules]

If the passive crossover is acting as a spring then this would manifest itself as worse transient response.

Here's the explanation as to why a passive crossover effects the way in which an amplifier controls the movement of a driver. http://avihifi.blogspot.co.uk/2010/03/active-speakers-does-anyone-understand.html

I can't think of any particular reason why a steeper roll off slope should sound better than a shallow one for all speakers.

When using a shallow 1st order (6dB/octave) crossover it will only be 12dB quieter 2 octaves below the crossover point. This means that the tweeter will still be audible and thus will be distorting because it's at too low a frequency. With an active crossover a steeper 4th or 8th order crossover is possible allowing the drivers to reproduce only the frequencies at which they work best. This means that they will distort less and give better clarity.

 

[steve_1979]

As for comment above that built in amplification will match what is required for the drivers, can the same be said for powered speakers?

Powered speakers will (usually) have well matched amplifiers that have been custom designed for that specific speaker. However because powered speakers only have one amplifier per speaker it can't possibly be perfectly optimised for both the woofer and the tweeter so there has to be a compromise to make it work well with both of the drivers.

Active speakers use separate amplifiers for both the tweeter and the woofer. This means that both drivers have their own perfectly optimised amplifier that works perfectly with that specific driver.

Or does the lack of an active crossover mean it's no different to passives with a separate amplifier?

Yes that's right. A powered speaker is just a passive speaker with the amplifier built in.

 

[hoopsontoast]

On what basis are you saying that the passive crossover adds a considerable amount of audible distortion? Have you or anyone else done a comprehensive set of measurements to measure the distortion

Yes it has been measured many times and is well documented in hifi and speaker engineering text books.

Also here's a link to Martin Grinrod's findings on active and passive crossover distortion. [LINK REMOVED - house rules]

If the passive crossover is acting as a spring then this would manifest itself as worse transient response.

Here's the explanation as to why a passive crossover effects the way in which an amplifier controls the movement of a driver. http://avihifi.blogspot.co.uk/2010/03/active-speakers-does-anyone-understand.html

I can't think of any particular reason why a steeper roll off slope should sound better than a shallow one for all speakers.

When using a shallow 1st order (6dB/octave) crossover it will only be 12dB quieter 2 octaves below the crossover point. This means that the tweeter will still be audible and thus will be distorting because it's at too low a frequency. With an active crossover a steeper 4th or 8th order crossover is possible allowing the drivers to reproduce only the frequencies at which they work best. This means that they will distort less and give better clarity.

Your links may be more credible if they were not linking to a site of the manufacturer who only makes ACTIVE speakers, I have not seen an independent set of measurements that prove less distortion for the same given speaker drivers/crossover in an active over a passive design.

Just saying.....

The 'distortion' you are refering ro in a passive speaker comes from wasted power as heat from the crossover components, so as long as the amplifier has enough power for your intended application (5-30watts will be fine for most domestic rooms) then you should not be getting any distortion from either the amp, crossover or drivers. There are so many variables, you have a big one in the drivers them selves, could be very cheap/poorly made and actually distort very quickly.

IMO and IME, you want some overlap in the crossover region to get good integration between the drive units. A first order crossover would be fine around 6-7kHz depending on the tweeter (and a mid bass driver that could comfortably go that high without excessive break up, or a full range driver), some tweeters can do ~1.5kHz 2nd order crossovers as they can be larger 30mm or 36mm domes with decent excursion.

You also have compression drivers, which when loaded in a suitable waveguide or horn, can easily handle a 2nd order slope between around 1kHz or more (for Hifi rather than PA use) with much reduced distortion over any dome tweeter.

 

[lindsayt]

Yes it has been measured many times and is well documented in hifi and speaker engineering text books.

Also here's a link to Martin Grinrod's findings on active and passive crossover distortion. [LINK REMOVED - house rules]

Can you please tell me which hi-fi and speaker engineering test books you are referring to? As I am unable to respond to anything in these text books if I don't know what they are and if I have never seen a copy of such text books. Would you be kind enough to let me borrow your copies of these text books?

The inductor measurements made by Martin Grindrod in his AVI forum post are woefully inadequate. He was measuring them at 10 watts. That equates to 113 dbs with my most efficient speakers and about 95 dbs with inefficient speakers similar to the AVI ADM 9’s. 113 dbs is 5 dbs louder than the active AVI ADM 9’s are capable of – without gross clipping distortion / risk of damaging the drivers. 95 dbs is very loud. What sort of joke non-real world measurement is this?

Now go back and measure these inductors at a range of power levels that equate to a range of in room volume levels from 30 dbs to 110 dbs

Something else to bear in mind is that with a 6db passive crossover the higher frequency unit has a capacitor connected in series with it and no inductors and will therefore have no inductor induced distortion. The inductor induced distortion will be on the lower frequency unit only. The harmonic distortion measured at the output of the inductor will be subject to the filtering effect of the crossover as well as the natural roll-off of the driver. So 1% THD at the inductor output will equate to less than 0.25% THD in room.

Martin Grindrod states that the active filters in the AVI ADM 9’s have distortion at -96dbs at the frequencies he measured the inductors at. These are filters that have op amps in the signal path. Op amps in which the THD+N distortion varies with the power / voltage output. Martin does not state at which power levels these distortion measurements were taken at. Looking at the data sheets for a few op amps indicate that they only give such low levels of distortion when they are used in their power comfort zone.

Now go back and measure the ADM9 active crossovers at a range of power levels that equate to a range of in room volume levels from 30 dbs to 108 dbs. Do not pass Go. Do not collect £200.

 

[lindsayt]

I can't think of any particular reason why a steeper roll off slope should sound better than a shallow one for all speakers.

When using a shallow 1st order (6dB/octave) crossover it will only be 12dB quieter 2 octaves below the crossover point. This means that the tweeter will still be audible and thus will be distorting because it's at too low a frequency. With an active crossover a steeper 4th or 8th order crossover is possible allowing the drivers to reproduce only the frequencies at which they work best. This means that they will distort less and give better clarity.

Surely that would depend upon the frequency at which the tweeter starts distorting and the amount of overlap between the tweeter and the midrange unit?

Also, how audible will the tweeter distortion really be if it is 12db quieter? Remember the tweeter will have natural roll-off of a few dbs per octave as well as the additional crossover roll-off. To keep the maths simple lets use a shallow natural roll-off of 4 dbs per octave. This means that the tweeter will be 20dbs quieter than the midrange unit 2 octaves below crossover point. -20 dbs equates to 1/100th the acoustic power level. So if the midrange unit is producing 0% distortion at this frequency and the tweeter is producing a horrendous 20% distortion we will have a total of 0.2% distortion from that speaker at that frequency. Which is not too bad.

Of course the reality is that the midrange unit will not be producing 0% distortion 2 octaves below the crossover frequency. There's a high chance that it will be producing more than 0.2% distortion - especially at higher volumes.

If we're using a passive crossover and change the crossover from a 6db to a 12 / 18 / 24 db design then we will be adding more potentially distortion inducing components to the crossover. If we're using an op amp based active crossover this device will be giving us more than 0.2% THD+N distortion at lower to moderate volume levels.

It's quite possible that a 6db passive crossover may will be the best compromise for overall system clarity and lack of distortion.