external active crossovers

[sfogg]

Tony,

"You are right there are preamps out there that can drive it BUT at

lowish volumes you will not be driving the input DACS sufficiently."

There is no difference there between consumer and pro levels. Any time

you turn down the volume ahead of the unit you are using less then the

full A/Ds resolution. That is why it is important to setup the system

such that the loudest material you listen at at the loudest you listen

it just below clipping the A/Ds. Where you see people complain about

these things is when they haven't gotten the levels through the units

done well.

"the crossover should ideally see constant voltage for optimal sound,"

Never going to happen. Volume in music changes... voltage changes. Ideally you should feed the crossover digitally if possible.

"volume should be controlled after the crossover ideally. right?"

Optimally, but that doesn't mean it can't work well ahead of it if you

set levels properly. A room is going to limit the systems SNR far more

then lowered levels into a digital crossover will. If one has a 50dB

noise floor in their room and listens at a peak level of 100dB they

have 50dB SN in their room. The Behringer is rated at 113dB SNR. If you

setup levels well through the unit you could likely get close to that

for your peaks. Even if you turn down the pre-amp (50dB of attenuation)

to the point where music is lost below the noise floor in your room you

still have around 60dB SNR through the Behringer. (About the same

amount of what the best vinyl can give you)

"that is what is marvelous about the DEQX, volume in digital domain. "

Digital volume control reduces resolution too. Digitally you attenuate

the signal... which means it is closer to the noise floor of the DAC.

End result... less resolution.... lowered SNR.

"with these other units one should have a singe channel passive volume

control after the crossover and before the power amps IMHO."

For tri-amping a pair of K'Horns they would need a six channel control.

If you do L/C/Rs you need a nine channel control. Not a lot of options

there.

Even with a the less then ideal setup IMO the advantages of the crossover far outweigh the negatives.

Shawn

[sunnysal]

Thanks Shawn,

I'm gonna print that one out, I can always count on you for useful information!

Warm regards, tony

[johnellis]

I am doing something slightly different and it has worked very, very well for me. I have tried both active and passive crossovers and each had thier pro's and con's. As a result, I decided to build a prototype and triamp my system using a passive crossover. A Cornwal Type B in fact. In short, here is how I did it....

1. CD out to preamp in

2. Preamp to out to Cornwal Type B crossover in.

3. Type B woofer out to amplifier in

4. Type B squawker out to amplifier in.

5. Type B tweeter out to amplifier in.

6. Woofer amplifier out wired directly to woofer

7. Squawker amplifier out wired directly to sqawker.

8. Tweeter amplifier out wired directly to tweeter.

At first, there was a slight hum. This problem was solved by grounding the Type B crossover back to the preamp. For testing, I spliced one end of el cheapo RCA interconnects and used the center wire (hot-red) for input/output and external wire to ground. I should also note that before doing this I spoke with Crown engineers and gave them the specs for the type B as well as what amp I was using. I was told that there would not be a problem doing this. My mids are driven by tubes therefore I contacted engineers @ Conrad Johnson and they said the same thing as the Crown engineers. Once again, no problem. Anyway, I hooked everything up and the sound was marvelous!! The bass was extremely tight, mids extremely clear. I also noticed that the attact and dynamics were lightning fast. The sound was also very, very open. In short, it was, by far, the best my system had ever sounded.

After running my system in this configuration for a number of months, I then decided to upgrade the stock Type B crossovers to 8 guage inductors, mundorf capacitors and a universal transformer. I also replaced my spliced interconnects with Cardas connectors and silver wire. Once again, this modification was also a giant leap forward. For me, this configuration has given me the best of both worlds as far as triamping is concerned.

Anyway, I just thought I would throw this in.

[tigerwoodKhorns]

Interesting, but, may I kindly ask, what is the benefit? Rane and other make active crossovers that are in the $300 - $500 range less. I thougth that the big benefit of an active is a steep slope (24 db/octive)

[sfogg]

Ummm.....passive crossovers need to be designed around the impedance they are driving.

The Type B was designed around loads of 8 or 16 ohm drivers.

Your amps likely have 10,000 ohms or much more of load on their inputs. The crossover points are going to *radically* change

with loads like that attached to them.

The engineers you talked to were either totally clueless or missed that

the crossovers you were intending to use were meant for speaker level

connections.

There are certainly ways of doing line level passive crossovers. This isn't it.

Shawn

[johnellis]

Shawn-

In my system, the crossover points radically changing has not been an issue. None whatsoever. I'v tried Klipsch Type B and the Thunder Bob passive in a traditional configuration. I've also tried Rane, Ashley and Behringer actives. Each had benefits but not one was "it". Like you, at first I was skeptical of this as well. But hearing (and tweaking) made me a believer. Needless to say it's easy to do and well worth a try. Let your ears be the judge. Who knows, you might be surprised!!

John

[nola]

Well, sooner or later I was going to have to pop the Q: Active vs passive Xovers......

I am on vacation now and a bit confused by this stuff.

I went to an audio place in LA for Pro Audio, in brief, active only on PA rigs. So......why not in consumer stuff ?????

Here are some anti passive xover URLs found via google. BTW I could not find any that said that passive was better; just that passive is more "convenient" or less expensive or easier to set up. Mind you, I have never heard anyone in a band seriously complain about xover set ups.

http://www.enjoythemusic.com/Magazine/manufacture/0403/

http://sound.westhost.com/lr-passive.htm

"Most people who have read my pages will know by now that I am not a fan of passive crossovers. However, sometimes it is the only sensible approach, or is necessary because of financial considerations or just for simplicity. Before deciding on the use of a passive rather than active crossover, the following article will surprise you - perhaps even enough to make you decide to go active after all."

My journey has included Crites recaps on my 2 AA networks for KHs and LSs and an ALK Uni kit.

I figure that if active was that much better, it would be an option offered by high end speaker companies. To the best of my knowledge, it isn't. We have an audio club in New Orleans and although I have never asked about active vs passive xovers over the past year, no one has mentioned using actives. I have heard spkrs well above Klipsch prices, including 13K Maggies and a 45K pair (forgot manuf). Surely the guy who paid 45k for a pr of spkrs can afford a K or 2 more if active is that much better.

I have read this thread and a couple of others elsewhere in the webesphere with interest tonight.

Given my rig (with addition of ALKs Trachorns and likely Altec 511 pruchase) where does one begin? Maybe with the units mentioned in the thread like the Ashley XR201 (?how many spkrs can 1 unit control) or Behringer ?DCN and DEQ 2496s for xover and EQ? Can these do both 2 way and 3 way active xovers? Can you do passive to the woofer and active between mid and tweeter? How to set these up (that is, real idiot proof instructions for noobs)? Etc.

Oh, have a happy 4th.)

NOLA in the other LA now

[DrWho]

The mass consumer world tends to be about 20 years behind the pro world...active xovers are the norm in almost all powered speaker designs now, which includes some of your highest end studio monitors. It's been that way since the early 90's. There are also many studios running external amps and active xovers too. The list of benefits is real long if you implement it correctly. Check out deqx.com for some modern high-end home audio gear.

[djk]

http://www.lansingheritage.org/images/altec/catalogs/1971-monitor/page6.jpg

[Cody_Mack]

I figure that if active was that much better, it would be an option offered by high end speaker companies. To the best of my knowledge, it isn't. We have an audio club in New Orleans and although I have never asked about active vs passive xovers over the past year, no one has mentioned using actives. I have heard spkrs well above Klipsch prices, including 13K Maggies and a 45K pair (forgot manuf). Surely the guy who paid 45k for a pr of spkrs can afford a K or 2 more if active is that much better.

NOLA,

Not only the cost to go with the active xover, but addittional two or three or more amps to pull it all together; now the guy who spends 45K on speakers is probably not using $500 amps, if you know what I'm saying.

Have fun in the other LA [H]

Rick