I need some help finishing up my budget build plan. In order to stay on my razor thin budget, I have the following plan for the front components on my civic sedan.
Amp: Zapco ST-2B
Tweeter: Peerless NE25VTS-04
Woofer: Silver Flute W17RC38-04
The part I need help with is the passive crossovers. I don't want to run active because of the added cost, so I'm aiming for clean sound without the stage. And tear apart my selection if you want lol I'm learning and researching as I go. Thanks in advance!
Nice, oldschool budget build! You don't see them too often nowadays - seems nobody answered your question, though...
You can do wonders with the right passive crossovers if your not afraid to experiment a little and can handle a solder iron reasonably.
With your 6.5 two-way setup you'd like to make the tweeter play as low frequency as possible to get the right stage and avoid the natural frequency gap that occurs with the fairly large 6.5 playing at an angle from your listening position. Typically you won't find a 6.5 that provides much output over 2-2.5k at 45 deg angle due to physical limitations - so that's where you want your tweeter to take over. Tweeters should be crossed over at least at resonance frequency (Fs) times 1.5-2 to avoid distorsion and safeguard power handling.
Your selected tweeter will work just fine, as it's speced at around 800 Hz Fs. I'd suggest a 4:th order (24 dB/octave) Linkwitz-Riley highpass for the tweeters at around 2-2,5 kHz, depending on what standard components (capacitors and coils) you can find. There are plenty of calculator tools available on the interweb if you give it a quick search - most of them have wiring schemes presented simple enough to follow. Prepare to insert an attenuation circuit (two additional resistors -one series/one parallell to the tweeter) - as you'd probably want to adjust tweeter level compared to the woofer after listening/measuring. There are calculators for those as well...
I'd however give the suggested Peerless DX20BF00-04 a thought if you can spare the room to fit it, as it - besides the price advantage - has a smoother radiation pattern which makes it less sensitive to on axis direction to your listening point. The one you've chosen is great in a straight line - but less so if angled...
If you're really on the tight budget - you could leave the woofer without crossover, many well known branded kits are delivered that way. If you decide to put a lowpass on - using a 2nd order (12 dB/octave) Linkwitz-Riley would do fine and save you a couple of bucks and some building time as you already have a natural roll-off around the frequency. If you go that way - one good thing could be to add impedance correction to the woofer to make the crossover work well, also flip polarity on either tweeters or woofers if you use this, as they otherwise would get out of phase at crossover frequency.
As a general tip, building with passives you want to be able to change and adjust - so fitting quick connectors like XT-60s on the cables is a smart move.
I hope that made some sense, at least tried to answer your question!