3 way crossover help

[jerome69]

Originally Posted by elves1111

if i used an active XO, do i need an amp per driver or would a 2 channel amp work?

One amp one driver

[elves1111]

thanks! so i can use the 5.5mH i already have instead of the 4.78mH? are you saying to wire a 10ohm "resistor" in series with the 7.5uF?sorry to ask such simple questions, so in "series" with the 7.5uF would be -__+ not +__+ like the cap,directly after it but before the inductor? and only the midrange inductor to 1.0mH, and leave the tweeter as .54uF? is .55uF thats 18 or 20 AWG air core inductor be adequate? So its 132.5uF for the highs, would a 150uF or 125uF Non-polarized Electrolytic Capacitor work, if not, what kind of capacitor? same question for the 7.5uF, is using a film and foil cap necessary? and finally, is the zobel circuit to reduce the tweeter by 4dB correct? since resistors can heat up easily, I calculated it for only 15 watts, which is the manufacturers claimed RMS for the tc120's, but they can handle 150w. will a 2.21 ohm 5.5 watt R wired parallel followed by a 10.26 ohm 3.49 watt R wired in series work for the tweeter? thanks again!! am going to sleep now, will check back in the morning...

[picowallspeaker]

Originally Posted by elves1111

.. and finally, is the zobel circuit to reduce the tweeter by 4dB correct?...

Usually, the RC is placed there to eliminate impedance peak at the resonant frequency Fs, so that the high-pass network would work more linearly .

[tinitus]

Originally Posted by elves1111

thanks! so i can use the 5.5mH i already have instead of the 4.78mH?

yes, and especially if its a better inductor
and try a smaller paralel cap, if you have one
mount it with series resistor 6R8-12R
5watt wirewound is ok, if thats what you have

[jerome69]

A lot of questions, i joined a schematic.
Yes for midrange-tweeters foils capacitor is highly recommended ! For test you an use bipolar.
If you can't have :
- 7.5uF use 8.2uF or 6.8uF.
- 0.55mh go to .47mH or 0.56mH
- 130uF go to 125uF instead 150uF, or use 100+33 or 2x68 or 4x33 etc.
Keep the resistor of the inductor below .5ohms, 0.3ohms is fine.

Originally Posted by elves1111

thanks! so i can use the 5.5mH i already have instead of the 4.78mH? are you saying to wire a 10ohm "resistor" in series with the 7.5uF?sorry to ask such simple questions, so in "series" with the 7.5uF would be -__+ not +__+ like the cap,directly after it but before the inductor? and only the midrange inductor to 1.0mH, and leave the tweeter as .54uF? is .55uF thats 18 or 20 AWG air core inductor be adequate? So its 132.5uF for the highs, would a 150uF or 125uF Non-polarized Electrolytic Capacitor work, if not, what kind of capacitor? same question for the 7.5uF, is using a film and foil cap necessary? and finally, is the zobel circuit to reduce the tweeter by 4dB correct? since resistors can heat up easily, I calculated it for only 15 watts, which is the manufacturers claimed RMS for the tc120's, but they can handle 150w. will a 2.21 ohm 5.5 watt R wired parallel followed by a 10.26 ohm 3.49 watt R wired in series work for the tweeter? thanks again!! am going to sleep now, will check back in the morning...

[tinitus]

Originally Posted by jerome69

For test you an use bipolar.

absolutely, and for more than just testing
just remember, you can always try and make a capacitor bigger by adding more in paralel
but you cannot make a big one smaller

bipolars comes in different quality too
roughed foil is used for higher capacity
for quality crossover best use 'smooth foil' caps
some of them might even outperform a film cap
but not always cheap either

edit, migt look at Mundorf E-cap AC (bipolar)
both smooth and rough foils

[balerit]

There is a mismatch between woofer and tweeter but you are matching them with the L-pad. The midrange needs to be 2dB higher than the woofer/tweeter. The tweeter must stay in phase, only the midrange gets it's connections reversed. The golden rule is to match the sensitivities of the woofer and tweeter exactly and get a midrange 2dB higher to make life easier. Have fun.
Mac.

[elves1111]

am definitely going to build this XO but have been thinking, since it could to cost $150 or more anyway, do you think that it will really improve the sound quality significantly? meanwhile, i could design a simple XO for the nht1259s and get a semi-decent 2-way bookshelf pair for similar price. for instance the SVsound SBS-02 are $150 for a pair on sale and the ascend acoustic CBM-170 are on sale for a couple hundred. have you heard either of these or know of some kickass speakers, prebuilt or kit, around $200 thatd be good for playing analog synths/drum machines thru? also been looking at the diysoundgroup.com MTG-08 speaker kit or the SEOS Delta 12a-kit. my main choice would be a gr-research N2X pair, but they're $500 so probably won't.

[tinitus]

its great fun, yes
use cheap inductors etc, and caps like those affordable Mundorf bipolar etc
but it will cost money
and it will still never be good enough for the serious money
if you have higher expectations, then its better to find a proven design you can copy
there are many good ones

and since I was around Curt's speaker projects for another member, here it is again
Im sure you can find a good and cheap project there
http://speakerdesignworks.com/index_page_2.html

but ofcourse there are others

[Moondog55]

The NHTs are very good woofers.
If you are having second and third thoughts about the project why not save for a couple of small plate amps and use the woofers in separate powered boxes??
Then find a reasonable 2-way project to use with them?
Going powered is the best ( and often cheaper ) option when talking about crossover frequencies below 200/120Hz