Don't go passive, go active, and preferably digital. Why:Hello, thanks for the feedbacks guys, really appreciate.
Interesting... I must say that sometimes I think it's too much go through the active crossover route on just my first project hehehe...
The other path that I consider, is multi-amplify, but with passive crossover, will put the passive crossover plan here, appreciate if you guys can take a look, and solve a doubt that I have about it.
View attachment 32616
As you can see, the woofer on the crossover plan is a different model to the one that I will purchase, I'm trying to figure out, if the crossover scheme of components will change, or will remains the same.
I will use:
http://www.loudspeakerdatabase.com/Fostex/FW305
Displayed on crossover scheme:
https://www.fostexinternational.com/docs/speaker_components/pdf/w300a2.pdf
Please, let me know, anything must be changed on the crossover scheme using the FW305 instead of the W300A?
Many thanks guys!
You do NOT wire together the woofer tweeter and midrange. If you did how would the music be separated into highs midranges and lows?
Think of the crossover as a black box. It has one pair of inputs labeled + and - which refer to the drivers going in and out (phase) it is important to observe those polarities so that at the crossover frequencies where two drivers are both "speaking" they add or subtract constructively rather than destructively which can happen if phase is incorrect. It has three pairs of outputs each with a plus and minus according to the diagram. These lead to the respective speakers. Additionally the attenuators go between the mid range and the tweeter, after the crossover. This is because if you did not have the attenuators the speakers would sound bright and harsh and not have a desireable frequency response because typically midranges and tweeters are more efficient than wooofers and need to be shelved down.
Juhazi mentions earth and ground. This is not correct. Speaker minus connections should not be considered earth and ground. The minus black connector on many amp outputs is grounded but this is not necessarily the case and on many amps connecting the black to ground will at the very least blow a fuse. Especially on single supply amps such as bridged class D amps.
It would be more economical and easier to biamp or triamp but you would have to solve the crossover question. You seem to not want to go digital.
Building a high level passive crossover requires expensive components such as your beautiful Fostex attenuators which I wonder how much those cost. But they reduce the damping factor by putting (complex) impedance between the crossover and the driver. But you do have to have level controls. In a triamp you just adjust the channels gain rather than amplifying the signal and then throwing the power away in an attenuator. With powerful amps available for practically free nowadays this is not that big a deal but if you are using a tube amp or a class A amp you may not have the power to spare. Additionally separate from the attenuator, crossover networks throw away a tremendous amount of the amplifier's power. The three way more than two way and four way more than three way. Such crossovers with lots of "ways" and steep slopes can easily eat two thirds of the amplifier power.
The Black wooden box you posted above is a very nice job of an external high level passive crossover. Yours should looks something like that.
If you want I could take a look at what you are doing on What'sApp or FB Messenger. (I don't do skype anymore because they keep demanding to know my birthday.)
I commend you on trying to bite off a little more than you can chew. This is how you learn. But the observation above that you need to learn to read a circuit diagram is correct. I can only imagine what those Fostexes cost and you DON'T want to blow them up. There are many tutorials on both schematic diagram reading and crossover network design. Both the crossover schematics you posted are standard looking designs and a crossover is not a moon shot (in spite of what some would like you to think). But implementing it well with high quality components will cost as much as triamping. Nonetheless if you insist on doing it that way, you need to make sure you get it right. Tri amping would actually be considerably easier.
Yep, your thinking is correct. But let me suggest a better solution (as I think):[..] I would like to propose a hypothetical solution about the active way, maybe I can learn more about the technical side.
Power Amps:
Two 3 channel amps https://www.hifiengine.com/manual_library/denon/poa-t3.shtml
Active crossover:
Analog 3 way: https://audio-heritage.jp/FOSTEX/etc/en3000.html
better pics here: https://www.hifido.co.jp/sold/17-11127-51780-00.html?LNG=E
Let me see if I understood how to set the frequencies division properly according to my drivers.
Low / Mid: My woofer can play till 3.5khz, and the horn starts to play at 800hz, so I can set at low/mid at 800hz or 1.2khz.
Mid / High: My Horn plays till 20khz, and the tweeter from 5khz till 40khz, so I can set the mid/high as 5khz or 8khz.
This thinking of the configurations options are correct? Please let me know your thoughts, I think I can learn more with this hypothetical solution.
Many thanks!!!!
Yes 800 and 5K would be good.
The Fostex crossover looks very nice if you can find one and its newer than the Sony or Pioneer.
Unless you already have a source for the Denon 3 channel amps I would look at three amps that are better matched to each driver. They don't need to be the same and it is likely better that they aren't. No tweeter can absorb 120 watts except a big PA monster. Not that you would set the volume that high. The Fostex propaganda refers to 120 60 and 50 Watt music power so the RMS continuous handling is probably half that. The music power ratings would be reasonable powers for the amps. The three channels would be convenient from a chassis point of view which would give you two rather than three chasis sitting around. I like more not less chasis
Yep, your thinking is correct. But let me suggest a better solution (as I think):
- get a Behringer DCX2496 Ultradrive Pro as crossover. It is much more flexible than the Fostex XO and can do all things I wrote about in posting #24:
- Use a sharp crossover (48 dB/Oct) for bass/mid so you can go as low as possible (800 Hz) with the mid horn. A 12" woofer is not very good at higher frequencies. My 3 way studio monitor has an 8" woofer and the crossover is at 650 Hz! You cannot do this with the Fostex.
- Use a time delay for woofer and tweeter to align with the mid horn. You cannot do this with the Fostex.
- Use the volume setting per channel to level match tweeter and mid with the woofer. This you can do with the Fostex as well.
- Use the channel EQ to fix the on axis frequency response. You cannot do this with the Fostex.
- Use the input EQ for room correction. You cannot do this with the Fostex.
- get a cheap beefy class D poweramp for the woofers, like the Behringer A500 or the Crown XLS 1502. The higher THD would not matter much because the ear is not so sensitive at low frequencies. On the other hand the woofer must play until 800 Hz ...
- get better poweramps with low power for mid and highs (40-50W could be more than sufficient, important is low noise due to high sensitivity of the horns). Sorry no recommendation here.
my concern with digital crossover, is that my main source is vinyl, don't want the phono signal be converted to digital and back to analog again
Hello Gene,
Thanks for this enlightening info, let me ask you some question about amp choices, and another thing about the crossover functionality.
Corssover: What is the 12 or 18db/octave function? I notice this on a lot of crossovers, what's the point of this function and how affects the sound? Also would like to understand more the 0 or 180 phase function, for what I understood about this, when taking a look at the top of the line active crossover that Fostex made, the EN3020, manual is available here: https://www.fostexinternational.com/docs/tech_support/manuals.shtml I think this one do not appears to sell very often like the EN3000 in Japan, and probably much more expensive, anyway, I noticed on the manual, that you can adjust the phase selecting between 0 or 180, and moving manually all the drivers in a way that their "motors" become aligned which other, which is what I can do with my speakers, see picture:
Amps: Would like to understand more about amp choices for each driver, and the power relation that you mentioned, I always thought that power is never too much, much more power available than the drivers will ever need, makes the amp work easy, and with more quality (big headroom of power available), but appears this is a misconception? But I also understand that one of the advantages of multi amp, is the option to choose amps that will combine their sound signature with the drivers characteristics, for example, low power Class A for the high sensitivity horn and tweeters, or tubes and etc....
Hello LTig,
Thanks for the Behringer suggestion, my concern with digital crossover, is that my main source is vinyl, don't want the phono signal be converted to digital and back to analog again, and I really liked the easy to use approach on the Fostex EN3000, veery straight forward, but we can talk about this subject later, otherwise my mind will be saturated with too much variables to start to learn at same time, and I will get lost again hehhehe.
Thanks guys, very grateful for your teachings.
Hey, still about the active crossover situation: there's any specs related to the crossover, that I must pay attention, related to the output voltage and input sensitivity?
This also applies to the active crossovers? They affect the relation of output voltage / input sensitivity in any way?
Not understood yet...
Real active crossovers? for example this one:
https://audio-heritage.jp/FOSTEX/etc/en3000.html
https://www.hifido.co.jp/sold/17-11127-51780-00.html?LNG=E
It's a "real active crossover"? that works as a line additional preamp or not?
For what I understood, taking this crossover by example, is that: will not occur changes on preamp output voltage with the crossover between the preamp and power amps
but I not understood how a preamp can have such a high output voltage to drive 6 power amps for example, I was thinking that the active crossover would increase the output voltage in order to drive multiple power amps...
I'm beginning to understand, so the active crossover act like an additional line level preamp, in fact, each channel is a line level preamp, that's why is possible to drive 3 separated power amps, that's makes sense?
Hmm.. so in resume, in order to know if a given active crossover will provide synergy with determined power amps, the specs verification is just like what you do when you consider a preamp + power amp combo
Verify what would be the output voltage (considering the source on the calculation), must be two times greater than power amp input sensitivity, impedance must be at least 10 times lower than the power amps.