Simple brief description of Passive V/S Active Speakers

[Audioman]

Passive Loudspeaker Systems
Passive loudspeaker systems are the most common kind one finds in the home hi-fi market as they are economical to build. A single amplifier which amplifies the whole audio signal from 20Hz to 20kHz drives the loudspeaker system. Inside the loudspeaker system, a passive crossover network splits the amplified signal into three way - high, mid and low frequency to the separate tweeter, midrange and woofer speaker drivers. These speaker systems at most, have a tweeter & midrange passive level adjustment. Since the crossover is after the amplifier, it is difficult to design variable passive filters in the crossover for low frequency slope adjustment / calibration, to correct the low frequency response in various acoustical environments or spatial loads. The passive crossover also introduces power losses, signal & phase distortion, thus deteriorating the quality of the audio reproduced

Active Loudspeaker Systems
Active loudspeaker systems are not so common in the home hi-fi market as they are expensive to build. Although these days they are becoming more and more popular in home audio, they are usually built for professional applications as their performance can be far superior to passive loudspeaker systems. Inside the active loudspeaker system, an active crossover network splits the line level signal into three way - high, mid and low frequencies to the separate tweeter, midrange and woofer power amplifiers to their respective speaker drivers. Since the signal split is done at line level before power amplification, it is easy to design and provide advanced active filters for adjustment / calibration of the low frequency slopes for various acoustical environments and spatial loads. Also circuits for driver time alignment and phase alignment and various necessary compensations can be incorporated. The result of this is a flatter frequency response, maximum amplifier-driver efficiency and minimum distortion.

 

[Thad E Ginathom]

I'm confused. To me, an "active speaker" is one which includes amplification, taking a line level input. The simplest has one stereo amplifier in one cabinet and a speaker cable leading to the the other cabinet. The most sophisticated may have a separate amplifier for each and every driver.

Is there something called active and passive crossover systems? Is that what you just illustrated?

Clarification please

 

[Audioman]

Conventional passive speaker systems use a single EXTERNAL full band amplifier per speaker system feeding a passive crossover which in turn feeds the speaker drivers. There are also powered speaker systems that also use a single INTERNAL full band amplifier per speaker system feeding a passive crossover which in turn feeds the speaker drivers. Both these are passive systems since they both use a passive crossovers between the amplifier and speaker drivers. The first drawing actually shows a powered speaker system as an example of a passive speaker system. It does not matter if the amplifier is in an external box or built into the loudspeaker cabinet.

Whilst active speaker systems use active (line level signal) crossovers that feed the individual amplifiers of the respective drivers. These are usually bi-amped or tri-amped speaker systems The second drawing shows an active speaker system with an active crossover. In this case too the entire electronics of the active crossover and amplifiers may be supplied in an external box or built into the loudspeaker cabinet

 

[Santy]

Firstly I assume this article is taken from net. If that is true, please quote the reference (URL).

Secondly I really think this is confusing. Yes there are passive and active crossovers, and 'powered speaker' may be the right terminology for 'speakers with built in amplifier', but in general, active speakers mean those which are self powered..

Thirdly, I wonder if there are speakers with active crossovers but without a power amplifier inside.

Edit: The image wouldn't lead earlier. Ya the pic shows there's a power amp for each driver.

Sent from my GT-I9001 using CTapatalk

 

[vktarun]

The basic idea is to split Entire Audio Spectrum into Bass ., Mid and High Freq before amplification (by help of an Active Crossover) and use seperate amplifier to amplify Bass, Midrange and High Frequencies.[Costly Solution]
[Typically, Low - 20-350Hz, Mid - 350-3,500Hz, High - 3,500-20,000Hz]

Now The crossover and amplifiers may be kept inside the Speaker Enclosure or it may be designed to keep outside.

The terms like "Active Speaker" or "Powered Speaker" only suggest that Speaker has an inbuilt amplifer. it may be One way, Two way or Three way.

The diagram that Audioman is referring to is basically "Three way Active Speaker"

Hey! one such "Two way Active" Set up is available for sale in our Forum.:licklips:
http://www.hifivision.com/sale-owner/23974-nad-c370-integrated-amp-nad-c270-power-amp-behringer-active-crossover-cx2310.html

One can also refer to the the Orion Speakers. [Most probably the best in class]
http://www.theorionspeakers.com/pdfs/Orion_4_Brochure2012_2Page.pdf


Happy Listening!

 

[Santy]

Edit done above

 

[Audioman]

Is there something called active and passive crossover systems?

Active speaker is one that has an active crossover. Since the input of the active crossover is a line level signal as you correctly describe, the output of the active crossover is also a line level signal feeding the inputs of the individual amplifiers of each driver

Firstly I assume this article is taken from net. If that is true, please quote the reference (URL).

Secondly I really think this is confusing. Yes there are passive and active crossovers, and 'powered speaker' may be the right terminology for 'speakers with built in amplifier', but in general, active speakers mean those which are self powered..

Thirdly, I wonder if there are speakers with active crossovers but without a power amplifier inside.

My text is not taken from the web. Its originally written by me and the drawings are also my own. You are right, active speakers are self powered because its active crossover outputs are line level signals that have to be fed to the inputs of the individual amplifiers of each driver. Just having inbuilt amplifiers in a speaker without an active crossover will not qualify it to be called an active speaker

The diagram that Audioman is referring to is basically "Three way Active Speaker"

Yes that diagram is of a tri-amplified active speaker system like a Genelec 1038B. If you look at the largest Genelec active speaker models, their entire electronics is in an external rack mount chassis and wired to the speaker with multicore speaker cables fitted with speakon connectors. This could be an example of an active speaker system having all external electronics

 

[Pandamaudio]

Its great to see this separate active loudspeaker category now on the HiFiVision forum. There are more than 30 active loudspeaker brands available in India that could be used for home hifi, if I were to name a few that I remember
Adam, Alesis, ATC, Avantone, Barefoot, Behringer, Blue Sky, Dynaudio, Event, Equator, F.A.R., Focal, Fostex, Genelec, JBL, K&H Neuman, KRK, Legend Acoustics, M-Audio, Mackie, Meridian, Meyer Sound, PMC, Quested, RCF, Roland, Samson, sE Electronics, Sonodyne, Spendor, Tannoy, Tapco, Yamaha etc etc.

 

[Audioman]

I'm confused. To me, an "active speaker" is one which includes amplification, taking a line level input. The simplest has one stereo amplifier in one cabinet and a speaker cable leading to the other cabinet. The most sophisticated may have a separate amplifier for each and every driver.

Is there something called active and passive crossover systems? Is that what you just illustrated?

Clarification please

Thad, I hope this new drawing clarifies your question The simplest that has one stereo amplifier in one cabinet and a speaker cable leading to the other cabinet is powered passive speaker system with a passive crossover. The most sophisticated that may have a separate amplifier for each and every driver is a proper active speaker system with an active crossover

 

[Thad E Ginathom]

Yes, it does. This, and some other stuff on the forum, just goes to show that some of us have been using the term wrongly.

 

[square_wave]

Active is always better. No doubt about it. BUT the amp and the active crossover should be sitting outside the speaker box.

All in-one solutions which have the amplifiers and crossovers in the same box come with its own problems. It is a cost effective solution though.

A speaker design should not have anything else stuffed inside its cabinet apart from engineering which complements and aids sound reproduction.

An amplifier and active crossover should sit outside in its own well engineered and isolated chassis which aids sound reproduction.

All in one power supplies are another can of worms !

 

[GeorgeO]

>Active is always better. No doubt about it.

Strong words!

I have 4 speaker systems all using passives and I am quite happy with them. Did consider going the active route on one project but it got a bit too rich for me, so I passed. The combo of the Behringer + 2 more amps was more than I could handle.

 

[square_wave]

Hey George,

I never said one cannot be happy with passive systems. A well setup passive setup will sound astounding.

However, If price is not a factor and if one were to implement a top notch active and passive system, the active will beat the passive. The absence of the passive crossover and dedicated amplification for each driver brings a very high level of realism to the sound. But a good active system is quite expensive to make. One of the reasons I never ventured into it.

A lot of these discussions are actually very academic in nature though. There is no socks that fits all in audio

 

[kanwar]

All in-one solutions which have the amplifiers and crossovers in the same box come with its own problems. All in one power supplies are another can of worms !

Hi SW,

Please elaborate how and why......

 

[Audioman]

Active is always better. No doubt about it. BUT the amp and the active crossover should be sitting outside the speaker box.

All in-one solutions which have the amplifiers and crossovers in the same box come with its own problems. It is a cost effective solution though.

A speaker design should not have anything else stuffed inside its cabinet apart from engineering which complements and aids sound reproduction.

An amplifier and active crossover should sit outside in its own well engineered and isolated chassis which aids sound reproduction.

All in one power supplies are another can of worms !

The drawback of external electronics brings the necessity of introducing longer speaker cables to wire the amplifiers to the speaker drivers. Incorrect speaker cable choices could introduce changes in the audio character if left to the end-user to decide and install. Having the amplifiers next to the drivers, could allow short thick speaker cables of only a few centimeters not bunched together inside the speaker cabinet optimizing the speaker cable performance.

Another drawback of having external electronics for active speakers is that they could be exchanged by mistake with other loudspeakers which they not optimized or calibrated for, leading to inaccurate performance if not worse.

Older wooden active speaker enclosures had an independent compartment at the back of the cabinet to house the entire electronics with adequate mechanical suspension to prevent vibrations to the electronics, and slots for air flow to cool the amplifiers. But the excessive space around the electronics needed for airflow and cooling inside the independent compartment, adds to the overall depth of the enclosure considerably. We know that excessive overall enclosure depth could lead to back-wall cancellations when the speaker is placed against a wall (2? half space). To avoid back wall cancellations when a speaker is placed at a wall, the overall enclosure depth has to be minimum. When the whole electronics is suitably located inside the enclosure, there is no space wasted and the enclosure depth can be minimized.

For this, the enclosure has to be cleverly designed to provide adequate cooling to the whole electronics mounted inside. Its not easy to mount the whole electronics inside a wooden enclosure as designing the cooling system for the electronics would be a bit tricky. The wooden enclosure is also flammable if the electronics goes up in flames. One solution is to design the entire loudspeaker enclosure using metal which acts as a large heatsink for the whole electronics, is not flammable and provides excellent shielding too

What are the problems you had in mind about the amplifier and crossover sitting inside the enclosure?

 

[square_wave]

The issues I have are to do with mostly the ones you described.

1. Vibrations to the amplifiers and the other entities.

2. Amplifiers and crossovers and sometimes even DSP units using the same power supplies. I cannot go into technical details here since this is not my core expertise area. From discussions with many folks who have taken these kind of designs to very high end levels, I understand that they give paramount importance to power supply design. And all these entities need exclusive designs. I can very easily hear the differences though.

3. The impossibility of implementing correct mechanical engineering practices for each of these entities since they all need to be located inside a speaker cabinet. You are limiting yourselves.

The problem of speaker cable length can be solved if you locate the amplifier close to the speakers and use longer interconnects. This is a standard practice by folks who do high end active setups. Most folks who do these kinds of elaborate active setups are very knowledgeable about cable engineering parameters so mistakes do not happen. Such folks are not the brass knob polishing audiophile variety.

Overall, my experience is listening to different active setups. I have not heard genelecs but some other equally regarded ones. If the definition of high end is the following; complete absence of electronic artifacts , the musicians in the room performing for you , absolute neutrality with correct tone and timbre --------- then these all one box speakers do not do it for me. I am not saying they are bad. They sound very good. And they will beat similarly priced passive setups in many parameters. But they fall apart when you compare to the really high end active setups and passive.

Now I am keeping this very open. If I hear an all in one box which I like and I am unable to hear a different variety which comes close to the all in one box, I will be a convert for sure. Only time can say

 

[square_wave]

Hi SW,

Please elaborate how and why......

Hey Kanwar,

I am not an electronic design engineer. Not my core expertise area I have only two experiences I can draw upon. One is discussion with designers. The other is experience with listening. I have listened to at least 3 all in one box designs and have never been impressed. Then had a discussion with a high end active setup designer about this and he pointed out these problems many of which I have listed above in another post. Then he went ahead and designed an active system in a different way which astounded me with its dynamics and natural sound. So the proof is in the pudding.

If you design an active all in one box which will beat the other one, I will not hesitate to believe you.

It is like the volume control vs active preamp discussion we had long back. Nelson Pass likes active line stages better than Volume controls and there has been much discussion on this line in the past. So what do we do ????

So that is the only answer I can give you

 

[anm]

Are active crossovers analog or digital or both?
Does the slope apply for digital crossovers as well? For digital crossovers, that take in digital signal, can we keep the slope infinite, so that there are no overlapping frequencies in different drivers?

 

[kanwar]

Are active crossovers analog or digital or both?
Does the slope apply for digital crossovers as well? For digital crossovers, that take in digital signal, can we keep the slope infinite, so that there are no overlapping frequencies in different drivers?

Active line level XO can be done in both Analog & Digital domain.
Any filter which does bandwidth division with respect to frequency has a finite slope which is also applicable in digital domain. Though in digital XO we can get much steeper slopes in order to minimize the overlap. But overlap to a certain degree is not bad at all.


my 2 cents,

Kanwar

 

[kanwar]

My replies in bold.

The issues I have are to do with mostly the ones you described.

1. Vibrations to the amplifiers and the other entities.
Vibrations can be dampened easily and solidstate electronics is not prone to distort or revert to some bad sounding gear, if done correctly.

2. Amplifiers and crossovers and sometimes even DSP units using the same power supplies. I cannot go into technical details here since this is not my core expertise area. From discussions with many folks who have taken these kind of designs to very high end levels, I understand that they give paramount importance to power supply design. And all these entities need exclusive designs. I can very easily hear the differences though.

Again it all depends on design and isolation of power supplies and tracks for digital and analog peripherals.

3. The impossibility of implementing correct mechanical engineering practices for each of these entities since they all need to be located inside a speaker cabinet. You are limiting yourselves.
I always prefer to house the electronics in separate chamber dedicated for that purpose only, same i did in Avepa Z-21 subwoofer, which has separate compartment for amp and is dampenend.

The problem of speaker cable length can be solved if you locate the amplifier close to the speakers and use longer interconnects. This is a standard practice by folks who do high end active setups. Most folks who do these kinds of elaborate active setups are very knowledgeable about cable engineering parameters so mistakes do not happen. Such folks are not the brass knob polishing audiophile variety.
Thats hardly an issue

Hey Kanwar,

I am not an electronic design engineer. Not my core expertise area I have only two experiences I can draw upon. One is discussion with designers. The other is experience with listening. I have listened to at least 3 all in one box designs and have never been impressed. Then had a discussion with a high end active setup designer about this and he pointed out these problems many of which I have listed above in another post. Then he went ahead and designed an active system in a different way which astounded me with its dynamics and natural sound. So the proof is in the pudding.

Depends on how a designer carries out the construction, its a technical aspect which is related to designer approach


So that is the only answer I can give you

Thanxz