Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

What do you think of passive crossovers?
What do you think of passive crossovers?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 29th September 2011, 01:14 AM   #21
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
What do you think of passive crossovers?
What 5th Element says is pretty much spot on. I'd particularily like to emphasize the comment about passive XOs creating rollercoaster-like impedance curves. This very often forces the need for a brute force amp instead of a finesse amp and having to suffer the limitations that brute force puts on the sonics.

WRT Pano's comment, he is likely hearing typical active XOs made with mediocre elecronics. It is hard to make a really good sounding active circuit XO, especially as the order climbs.

Not mentioned yet, and often overlooked, is that active makes it much easier to make use of current amps.

And an aside, Earl's comments on active need to be weighed with his belief that amplifiers are almost perfect and i envision his multiamped setup using a stack of HT receivers.

Quote:
Originally Posted by rob g View Post
Earl's speakers need subwoofers since they are not asked to produce much bass.
Active subwoofers. So Earl's speakers use both active & passive crossovers. Often this makes a llot of sense.

As in most things, it comes down to execution, and the art of balancing the compromises.

Digital XOs have a lot of promise, but are still immature (which doesn't say what you can get now isn't useful, just that they are going to get way better) and it would be nice to see the sampling rates go up.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 29th September 2011, 01:20 AM   #22
bbggg is offline bbggg  United States
diyAudio Member
 
Join Date: May 2007
Passive crossovers are entirely unfit for purpose: they are finicky and fickle, drift with age, interact with magnets and with themselves, severely compromise amplifier control over drivers, they botch a ton of issues they are otherwise unable to correct, they screw time behavior, and also dynamic behavior, so please don't get me started.
__________________
High current requirement is the bane of high fidelity
  Reply With Quote
Old 29th September 2011, 01:45 AM   #23
5th element is offline 5th element  United Kingdom
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Quote:
Originally Posted by vacuphile View Post
Some very good loudspeakers with passive xovers have been made. But it is an outdated technology.
This I disagree with, if the system doesn't need anything other then a simple passive crossover, then going active adds in complexity and cost. It will increase the failure rate and possibly increase the amount of expertise required to operate. There is no replacement for a simple passive crossover if the simple passive crossover achieves all of the necessary design goals.

Quote:
Originally Posted by vacuphile View Post
The only way to realize real progress in sound reproduction i.m.o. is to mate optimal amplification with individual drivers, and to design active xovers that take accoustic driver specifics into account.
This I agree with but again I point to the first bit where a lot of the time one doesn't need to go active to take the driver specifics into account. This is more relevant in simple two ways with reasonably well behaved drivers, which should describe the vast majority of individually bought stereo pairs of loudspeakers. Can you go active for a small gain or even a widely appreciated gain(and by this I mean Joe public recognises the gain and would prefer to have it)? Yes. It is going to be a good large scale idea as a way of making money, not really (Joe public isn't interested in it if it costs him more and has the potential to be a hassle). Now whether or not this is relevant is another thing, coming from a DIY website where the goal is superior audio, we do not mind going the extra mile. Also if you're selling to a small niche for which superior audio is the no.1 priority then the extra costs/complexity do not matter as much either, but in a global scale economy, active, as of yet, doesn't have a place, because it is more expensive and it does have a greater chance of failing.

This is something however that I see changing as time goes on as DSPs are becoming cheaper and single chip multichannel class D amplifiers with built in DSP capabilities are starting to appear. It is only a matter of time until these become common place and then going active might be more cost effective and will certainly provide better performance. A cheap multichannel class D amp with 4 advanced biquads per channel is certainly going to provide a better crossover then the single cap on the tweeter, woofer run full range variety of mini systems. And if this actually happens then the general public will start to experience better quality sound as the loudspeaker is by far the weakest part of any sound system.

Quote:
Originally Posted by vacuphile View Post
With passive xovers, you have to deal with both accoustic and electrical specifics (Le, resonant peaks, thermal effects). You avoid all that electrical hassle by going active.
Resonant peaks are handled in exactly the same way if active or passive, all you're doing is reducing the amount of signal reaching the driver. All active has over passive in this regard is that its effects remains constant regardless of how hot the voice coil is.


Quote:
Originally Posted by vacuphile View Post
Plus, the sort of compensations you would want to make because of driver accoustics, are 10 times easier realized in silicon sprinkled with some passives, than in big copper coils and fat caps. Think about the cost too.
This isn't necessarily true, Zaph applies a bottomless notch to some of his metal cone designs by using one small capacitor in parallel with the primary inductor. You can also compensate for driver acoustics fairly easily with a passive crossover if you know what you're doing. Passive crossovers only really become expensive if you're interested in using boutique caps/coils, or you're crossing over quite low where the values start to sky rocket. You'd have to have a pretty complex passive crossover for an active one to end up cheaper, power amplifiers cost quite a lot too remember.

Active can do things that passive cannot. If you need these capabilities then it's a no brainer, you go active (Like Linkwitz does). However as stated before, if you do not need these capabilities then it is generally a waste of money going active.

If you're in the position of building all of the electronics yourself then it is quite trivial, generally speaking, to add in another two more power amplifier channels to a design, providing they are low power. Also building a decent active crossover isn't hard nor expensive. Doing these things in an optimum way, if you're buying and not building, will cost you quite a lot for the luxury of going active though. Not to mention you need the know-how to be able to build the things competently in the first place. It is for these reasons that I have not gone the DSP route until recently, times are changing however and as a result, going this route is now far easier then it was a couple of years ago. As Dave has stated DSPs are only just starting to come into their own, give it another 10 years and who knows what will happen.


Quote:
Originally Posted by CharlieLaub View Post
You must tailor the system SPL to the lowest sensitivity driver with a passive crossover. Try boosting signal/power delivery using a passive circuit, e.g. EQ - you can't! All you can do is direct or dispose of the power coming out of the amplifier.
Which describes in my opinion the number one limitation of passive crossovers. They can only cut, not boost.

Quote:
Originally Posted by 18Hurts View Post

Can I vote active subwoofers and passive mid/tweet filters?
Of course you can, this is after-all part of the thread and it's already been somewhat decided that active only makes sense when in the right application. Low frequency crossovers and equalisation is where active crossovers truly shine and prove their worth, such as in a sub. If there is already a power source and a dedicated amplifier present, it is a lot cheaper to implement an active crossover over a passive one, one TL072 + 1 worth of resistors and caps and a simple zener regulated power supply? Yes please.

Quote:
Originally Posted by gainphile View Post
Passive crossovers are expensive, difficult to implement, and have limited application. Except for insistance to use a single typical stereo amplifier I don't see any benefit of using them?
Passive crossovers are not difficult to implement/design, if you know what you are doing, nor are they more expensive then an active counterpart unless you're doing something you should really be doing with an active crossover in the first place.

One benefit to a passive crossover is rejection of noise. Sure it's a fairly poor advantage as any really well designed piece of electrical equipment should have low levels of hiss and very low amounts of hum, but these things do exist. If you've got a 2 way passive loudspeaker with a woofer dictated nominal sensitivity of 82dB and you're using a 92dB tweeter. In an active system the tweeter might annoy you because you can hear a faint level of hiss. In the passive system however the tweeters level is cut by 10dB and you can no longer hear it. This is a real world problem and DIYers go to a lot of effort in their self built active systems to reduce the levels of hum and hiss to negligible levels. Also the potential for increasing the levels of hum/hiss goes up when you add an active crossover to the system. To some people this is enough reason to stay passive!

Quote:
Originally Posted by Pano View Post
Geddes speakers big? The Abbeys sure aren't. They're no bigger than most bookshelf speakers.
I think you're being somewhat optimistic here. The Abbey's are 29" x 15" x 12" and have a 12" driver and the volume they occupy is around 85 litres. When I think bookshelf speaker I think 5-6.5" mid/bass + 1" dome tweeter. These typically occupy about 10-20 litres, so are considerably smaller. Most significant others would balk at the Abbey's. You can hide a ProAc Tablette Anniversary, you cannot easily hide an Abbey under a doily and a potted plant/table lamp.

Quote:
Originally Posted by Pano View Post
IMO the reason most folks rave about the advantages of active crossovers is simply because they are easier to get right. That's a huge advantage for the DIY guy. His chances of success are far greater.
This I believe is probably the number one reason why the DIY crowd love active crossovers. They are more predictable in their effect because they aren't dependent on the drivers impedance curve and they are easier to tweak. If however you posses the knowledge and capabilities to accurately simulate and design a passive loudspeaker (people such as Zaph and Earl) then you will have equal success (providing that passive will accomplish all of the necessary design goals) with both passive and active. Now which one ends up costing more will depend entirely on the design.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Now with website! www.5een.co.uk under construction.
  Reply With Quote
Old 29th September 2011, 01:46 AM   #24
whgeiger is offline whgeiger  United States
diyAudio Member
 
Join Date: May 2004
Location: Pensacola, Florida
Default Digital vs Analog

Quote:
Originally Posted by Boscoe View Post
Some hate them and will never use anything other than active, they say due to high distortion brought on by amplifier damping.

What do you think? Do you like the sound of active over passive?
..would be a more useful comparison.

If the drivers of a loudspeaker system are directly connected to amplifiers designed specifically to drive them and the signal has been conditioned and channelized beforehand by a digital front end (DSP), it would be reasonable to assume that the result would produce sound superior in quality to that of other arrangements.

For most, it is a digital world, sans the scratch of vinyl and the hiss of analog tape. This technology, slowly but surely, is finding its way into loudspeaker systems as well. To argue that such an approach is unable to surpass other vintage analog methods is utter nonsense.

Regards,

WHG
  Reply With Quote
Old 29th September 2011, 02:23 AM   #25
5th element is offline 5th element  United Kingdom
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Quote:
Originally Posted by bbggg View Post
Passive crossovers are entirely unfit for purpose:
Which could be true, but what purpose would that be?


Quote:
Originally Posted by bbggg View Post
they are finicky and fickle,
On the contrary they are entirely predictable. Do you think Zaph and Earl and every other competent loudspeaker manufacturer/designer go through tens of hundreds of iterations because their simulations don't match up to the real world? Hardly, they most likely go through a maximum of around five designs that are all very similar and then one is chosen after auditioning. They could even possibly do all of the experimenting with a digital box of tricks, then replicate the design passively once they've decided what sounds the best. If you're in the habit of designing lots of loudspeakers this is one situation where having an active DSP setup makes a lot of sense. It saves you time in trying one crossover to the next and it saves you money in needing to have a large parts inventory.

Quote:
Originally Posted by bbggg View Post
drift with age,
Only electrolytics will do this and even then a good lytic will probably outlast the use of the loudspeaker.

Quote:
Originally Posted by bbggg View Post
interact with magnets and with themselves,
Only inductors will do this in any meaningful way and you can easily get around this by mounting the inductors away from themselves and loudspeaker magnets and in certain orientations.

Placement of coils in crossover networks


Quote:
Originally Posted by bbggg View Post
severely compromise amplifier control over drivers,
It's precisely this lack of control that you are wanting to create otherwise a passive crossover would not work. How else do you think a cap reduces the level of bass delivered to a tweeter? It tends to effectively decouple the tweeter from the amplifiers output as frequency decreases, if it did not do this, it would not work.

Quote:
Originally Posted by bbggg View Post
they botch a ton of issues they are otherwise unable to correct,
If a passive crossover is capable of dealing with an issue then it can deal with it just fine. If however it is unable of dealing with an issue then it cannot deal with it. They do not however tend to create issues simply by their existence.

Quote:
Originally Posted by bbggg View Post
they screw time behavior,
They do not screw time behaviour, they modify it and in an entirely predictable way, this is also true for the vast majority of active crossovers, be they analogue or digital.


Quote:
Originally Posted by bbggg View Post
and also dynamic behavior,
For this to occur the crossover would need to reduce the peak of a transient to something lower then it should ideally be, or perhaps retard the decay of an impulse. Whether or not a passive component would do the first I do not know, do they show non linearities that change with respect to amplitude if used within their capabilities? The latter is certainly true, series resistance can be added to change the Q of a system such that it will alter the group delay, however it is also predictable and can be factored into the design. In reality though voice coil heating probably has far more impact on altering/limiting dynamics.

From all of this is seems that I could be somewhat against active crossovers, this could not be further from the truth and I use them almost religiously in my main system. The loudspeakers in the kitchen and bedrooms get passive crossovers though, why? Because they are better suited.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Now with website! www.5een.co.uk under construction.
  Reply With Quote
Old 29th September 2011, 02:46 AM   #26
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
What do you think of passive crossovers?
Quote:
Originally Posted by planet10 View Post
WRT Pano's comment, he is likely hearing typical active XOs made with mediocre elecronics.
Yes, like that awful POS the Kaneda active crossover. And those valve jobs. Horrid.

I don't mind the active crossover fanboys, it leaves the passive filters to the real designers.
  Reply With Quote
Old 29th September 2011, 03:15 AM   #27
gainphile is offline gainphile  Australia
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
Quote:
Originally Posted by gedlee
but "expensive" that is completely ridiculous, they are cheap by comparison with a DSP box and another amplifier - get real!
Passive xo can easily reach $400-$800 mark. Big inductors are expensive. Then build another speakers, and more investments are needed.

MiniDSP can be had for $200 and you'd get 8 channels. Build another speakers just by uploading new config.

Great amps can be had for $100 -- and that's 8 channels.

Again I see no reasons for passive, except when using single stereo amp is desired. Or perhaps someone who wants to build a once-off kit and be done with it.
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 29th September 2011, 03:23 AM   #28
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
What do you think of passive crossovers?
Quote:
Originally Posted by gainphile View Post
MiniDSP
I just wish it had a decent sampling rate.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 29th September 2011, 03:32 AM   #29
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
What do you think of passive crossovers?
Quote:
Originally Posted by Pano View Post
You can bi or tri-amp with passive too, you know.
I thought about a mix actually with passive on the mid horn and HF horn, with passive line level X-O between the bass unit and the mids & highs - depending on how capable the GM70 SE turns out to be it might get to do the bottom end and not run full range like the 300B does..
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 29th September 2011, 03:34 AM   #30
gainphile is offline gainphile  Australia
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
Quote:
Originally Posted by planet10 View Post
I just wish it had a decent sampling rate.

dave
For $300 you'd get the 96khz variant. And 8 channels.
__________________
http://gainphile.blogspot.com
  Reply With Quote

Reply


What do you think of passive crossovers?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Passive Crossovers, Two Amplifiers davidbosch Solid State 1 19th January 2011 09:34 PM
passive crossovers.... stuman Subwoofers 10 8th December 2009 02:44 AM
why do we bother with passive crossovers? paulspencer Multi-Way 70 13th September 2004 07:06 AM
dB loss by using passive crossovers? Active vs Passive and 1st vs 4th order Hybrid fourdoor Multi-Way 3 11th July 2004 09:16 PM
Solder for passive crossovers. JoeBob Multi-Way 8 31st December 2001 04:28 PM


New To Site? Need Help?

All times are GMT. The time now is 07:02 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki