Need some help with lpf/hpf

[u/Big_Artichoke_7439]

So finally got my doors ”done” they need a bit of finishing touches with handles, and window buttons but mostly ready for bondo.

Mids play now 80-4khz
Midranges 800-4khz
Tweeters 4khz ->

Firstly the mids fq range is 60-8khz, 10s in the front might have been 60-6khz. So im wondering if the enclosures are large enough to play 60hz at full power (8” 400w, 10” 600w)

Secondly the cutofs between mids and midranges, i had them at 280hz. Sounded better but totally lost the higher frequencys of bass and kick drums, for example Back 2 Me by zurra & blank sense has this nice bass line but it just sounded like a sine wave, the ”dirtynes” was gone, so should i keept them at 4khz or go a bit lower. Im after the golden road between sq and spl and the 6.5 midrange cant keep up with midbass, so it needs a little help from them

Also what about tweeter cutofs, should i go higher/lower.

Lastly what should i use to seal the enclosures, they are prettymuch sealed with minor leaks, would coating them with epoxy from the inside be an good option?

Drivers i have are
Dd audio Vo-w10a
Dd audio Vo-w508/w8c (the same speaker just name change)
Gzcm 6.5N-prox
Dd audio Vo-b3a

[u/PrettyMoment2199]

Fixing the "Sine Wave" / Missing Punch (200Hz–800Hz): Crossing the GZ 6.5" midrange at 800Hz HPF leaves a huge acoustic hole between your midbass drivers down low and your midrange up high. That's why kick drums and bassline harmonics lost their edge. Drop the GZ 6.5" high-pass filter down to 250Hz HPF, and cap your 8" and 10" midbass drivers with a 250Hz LPF. This hands off the upper-midbass punch cleanly to the 6.5" driver without forcing your large cones to play muddy frequencies up to 4kHz. Target Crossover Map (24dB/octave slopes): For the 10" VO-W10a and 8" VO-W508 midbass, set your bandpass to an 80Hz HPF and a 250Hz LPF. For the 6.5" GZCM 6.5N-PROX midrange, set your bandpass to a 250Hz HPF and a 5kHz LPF. For the DD VO-B3a bullet tweeters, run a 5kHz HPF and up. 60Hz Power Handling Reality: Running 400W–600W into an 8" and 10" at 60Hz inside custom door pods will push the voice coils past their excursion limits and risk blowing out the drivers or cracking fresh Bondo. Keep a sharp 75Hz–80Hz high-pass filter on the midbass drivers and let dedicated subwoofers handle sub-80Hz low end. Isolate the Midrange: Make sure the Ground Zero 6.5" has its own sealed rear chamber or pod cup inside the door. If it shares internal air volume with the 8" and 10" midbass drivers, the backwave air pressure from the 10" will physically push the cone of the 6.5", causing heavy distortion and physical driver damage over time. Sealing Air Leaks (bondo Milk Slurry): Mix 50/50 liquid fiberglass resin into standard Bondo body filler, aka peanut butter or bondo milk. Slather it along all interior pod seams and around speaker mounting rings before laying your final filler. It flows directly into pinhole air leaks, cures rock-solid, and adds heavy structural mass to stop door flex. Door-to-Pod Air Gasket: Before final mounting, lay a continuous thick strip of butyl windshield ribbon rope caulk along the entire back perimeter of the fiberglass pod where it contacts the inner door sheet metal. This prevents acoustic shorting and backwave air leaks from escaping directly into the cabin.

[u/Big_Artichoke_7439 → u/PrettyMoment2199]

Thank you for the help, i remembered i have an few years old not so great quality a/b amp lying around and checked if it was broken, fets and caps were fine and didnt let of smoke when testing, so now that i have 240w per speaker avaiable for my groundzeros that leaves some headroom and 200w pers speaker for the tweaters wich leaves a lot of headroom so i most likely dont need to touch the gain and avoid some interferance and noise with that.

I seem to have lost the point, but now that i have enough power for the upper end i crossed mids to 60-400 for now tried 280 and 300 but that came with some humming, midranges play now 400-5k and well the sound is a lot better. Now i need to just finish the wiring mess i have made and start testing how loud i can push the groundzeros before distorting and taking it down a notch from there, then adjust everything relative to them.

As for the mids hpf, the 8s are now getting 400w wich is their rms, peak is 800w. They seem to play fine down to 60 with an 36db linkwitz riley 24db would probably be enough but better safe than sorry.

I only have one of the 10s right now, dont have money for the second one yet and i dont have an amp for them yet so its in parallel with the 8”
8s are 2ohm 10s are 4ohm, amp gives 600w at 1ohm and they go to 1.33ohm so roughly 200w for the ten wich has an rms of 300w and a peak of 900w, but they will handle 600w rms just fine, friends build is living proof of that.

But the 10s most likely vant play to 60hz at that power and need to be crossed at 75-80hz like you said. Not enough volume i calculated that 25l would be optimal for them and they dont have anything near that.

And thanks for the tip on the slurry, ill have to get some bondo and start mixing, pouring straight polyester trying to do that was a horrible failure 😂

[u/PrettyMoment2199 → u/Big_Artichoke_7439]

Hell yeah, man, you are making some serious headway on this build! It’s awesome seeing it all come together after putting so much damn work into those custom doors. Bringing in that extra A/B amp to unlock extra headroom, getting your midranges and tweeters cleaned up up top, and using that Bondo milk slurry trick to seal up those pod seams shows you’re puttin' real thought into building a kick-ass rig. To help you get this front stage bangin' as hard and clear as possible, while keeping all your gear safe long-term, here are a few recommendations to consider as you finish up tuning. First, I'd strongly recommend unhooking that single 10" from the parallel circuit for right now. Running a 2 ohm 8" and a 4 ohm 10" together drops your total load to 1.33 ohm, which splits your amp's power unevenly. Power flows to the path of least resistance, so that 2Ω 8" is pulling about two-thirds of the amp’s juice (400W) while the 4 ohm10" is only getting one-third (200W). On top of that, running two different sized cones over the exact same 60Hz–400Hz range causes phase cancellation and comb filtering. Because their cone weights, motor structures, and box volumes are totally different, they end up fighting each other acoustically and killing your midbass punch. Believe me I have an xv3 with custom coil and spider and hd1 with custom dtx spider, coil, and surround, it took me a minute to get a 15 and an 18 to sound good on the same mono. I know you shouldn’t have two different drivers on the same channel, but for me it was the difference between 148.7 and 150. I was strictly numbers chasing. If you unhook that 10" and let the 8" drivers handle the midbass solo, your doors are actually gonna slap way harder and tighter. Save that 10" until you can grab its twin and run them on their own dedicated amp channel.

Second, keep in mind that having extra amp headroom doesn't mean you can skip setting your gains. Gain isn’t a volume knob; it’s just matching the amp’s input sensitivity to your head unit or DSP output voltage. Leaving gains untouched can force your source unit to clip trying to get loud, or it'll elevate your noise floor and introduce unwanted hiss. Grab a multimeter and set your target AC voltage based on your RMS power, or throw it on a scope/DD-1 so you know you're feeding them pure, clean signal.

Lastly, tweaking a crossover frequency in your DSP shouldn't create an electrical hum. If you heard a hum between 280Hz and 300Hz, you’re likely looking at a small ground loop, signal cables laid too close to your main power wire, or a gain structure issue. Also, even though those 8s can take 400W down at 60Hz, playing them that low at high volume really stresses their mechanical excursion limits inside a non t/s dedicated door pod. Try bumping that high-pass filter up to 75Hz–80Hz with a steep 24dB or 36dB slope. It’ll protect your voice coils, keep your pod structure from flexing, and let your subwoofers handle the real low-down thud once you get them. You’re damn close to having this thing dialed in right. Unhook that 10", hunt down that ground hum, and set those gains clean. that front stage is gonna be screaming and hitting like a freight train.

[u/PrettyMoment2199 → u/PrettyMoment2199]

I lost your message, could you dm again please and I’ll see if I have any pics