|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
90.149.115.79
(This issue touch other forums as well)
My selfmade SET amps (RE604/WE300B) are driving LF and HF horns through 600HZ passive biamplification designed by Maison de L'Audiophile.
May be it is room for improvement, and I'm looking for a solution.
Passive biamp. is not widely used, but is it so that
active crossovers are superior to passive crossovers?
Any opinions about this issue?
Follow Ups:
You will find many opinions on this question. My best advice is to seek the specific experience behind the opinion and ignore the conclusions drawn from that experience - draw your own conclusions if you must. In too many cases you can't get back to the experience by itself, which is unfortunate but completely human. Theory is close to useless, except to provide a comfortable reason to believe you own prejudices. I say that even though I am a theoretician myself ... :^)
My experience has been that high order line level crossovers sound better than passive speaker level crossovers, and that low-order speaker level crossovers sound better than high order ones. I have little direct experience with low order line level crossovers.
For what it's worth, active crossovers are usually feedback circuits, not simple gain stages following a passive network. Since one of the virtues of SETs is their lack of feedback, I am suspicious of active circuits - but as I said, that's theory and therefor nearly useless.
Incidentally, danlaudionut says "Caps are bad but inductors are lethal." There are others who say "Caps are bad, inductors are good." I'm not choosing, since I don't have a large enough base of direct personal experience - I'm just reporting the range of opinions I've seen.
Paul
I love inductors as plate loads.
I have 10 pieces of iron in my amp.
I have 8 pieces of iron in my DAC/Preamp.
I have 10 pieces of iron in my Phono Stage.
I hate inductors between amps and drivers.
The amps ability to control the driver is
seriously impeded by the inductor.
Tube amps especially are handicapped
because of their low DF.
DanL
Not if mid bass is 24ohm and 106db 1 watt then inductor is the best way. This all comes down to end design some loudspeakers and systems would do best active some passive. I use simple passive on my designs unless for subbass use then active steep slope. I also gave up biamping from 70hz-25khz on my horn systems if design is proper biamping in this range negatively effects sound quality. But below 70hz or so it doesn't matter to end result and is preferable to running tubes on low bass. So I biamp with active SS on bass horn and run rest simple passive best of both worlds plus I need no level matching.
Steyr
I took a look at your website
to see what you design with...
The Seas W8 X2-08 (above graph)
looks like it could use some
decoupling to tame or dampen
the erratic frequency response.
The Seas X1-04 is not much better.
But a whizzer cone for HF ???
How retro of you 8^D Never heard
a whizzer that satisfied me.
But a Raal Ribbon for HF ...
that's more like it - AWESOME!
And not to mention the Fostex
FW800HS 31.5" woofer - impressive.
Definitely needs to stay away
from 500Hz like most sub drivers.
Your choice in drivers is expensive,
at ~$800 a piece for the Seas
and $3.5K for the sub driver.
And I thought $250 a piece was
alot for a Dynaudio tweeter !!!
I am sure they MUST have something
going for them at that price.
But the "normal" priced drivers that
most of us use would benefit from
bi-amping to get the best out of them.
DanL
These dipoles turned out well. Maybe more your cup of tea. Has another 8in back firing loaded in ported cabinet.
DanL
Iodemus
Caps are bad but inductors are lethal.
The same goes for resistors too.
If you can go active, do it !
You won't be sorry.
I use no inductors or resistors in my system.
Motor Run Cap bypassed with VitQ for the tweeter
and the woofer has it's own seperate amp with
active crossover for below 200Hz operation.
Midrange is the tricky one though.
Finding a midrange that has a smooth roll-off on
BOTH ends is hard but worth it.
DanL
I agree with you to keep it as simple as possible.
The passive filter I use now has only a cap (6dB)to the Altec HF-horn and a 12 dB LC filter to the Klipsch Belle woofer.
Volum to 10 o'clock is enough so I don't need the amplification an active filter can provide. An active filter is only a passive filter with amplification, isn't that the only difference. Am I wrong?
Iodemus
The difference is the load.
In an active filter, the load is a grid leak
resistor which is a constant LCR
(Inductance/Capacitance/Resistance) load never
changing at different frequencies or volumes.
In a passive filter, the load is a speaker with
various LCR ratings that change with volume and
with frequency as well as decreasing the
dampening factor with every componant.
The less you have between the amp and the speaker
the better the amp can control the speaker.
The better the amp controls the speaker, the clearer
the sound and the wider the frequency responce.
DanL
The filter is between the preamp and poweramps, only a cable is between the poweramps and the speakers..
Iodemus
When I say speakers I am referring
to the speaker drivers themselves.
The LP and HP filters also act to
decouple the drivers from the amp.
Tweeters aren't very hard to control
BUT the lower you go in frequency
the tougher it is to control the drivers
because of the diaphram excursion.
I could go on and on but ...
hearing is believing.
DanL
So you are talking about line level filters. Then the issue is the output impedance of the preamp and the input impedance of the amp and what effect they will have in interaction with the selected filter components. The active circuitry in an active crossover is not usually used for a gain increase but rather as a buffer that keeps the aforementioned interaction to a minimum.There is no simple answer as to which is better because each requires an implementation specifically for the given system. For example if the passive setup is not optimal in terms of impedance and the active setup is, the active setup may sound better even though it may add more coloration from the active circuitry.
Edits: 07/05/11
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: