Hi guys,

My F540 (4x50rms @ 12V) has quite a flexible crossover, with both a selectable high-pass and low-pass on each pair of channels

the high-pass can be set to either:
- 15Hz-400Hz at 12db/octave.
- 300Hz-8kHz at 12db/octave (using a x20 frequency multiplier switch).

the low-pass can be set to either:
- 30Hz-400Hz at 12db/octave
- 600Hz-8kHz at 12db/octave (using a x20 frequency multiplier switch).

My headunit is a Clarion DXZ935, which has an inbuilt:
- high-pass filter at 50/80/120Hz at 12dB/octave for front and rear channels.
- low-pass filter at 50/80/120Hz at 18db/octave for subwoofer channel.
- Parametric EQ with 3 bands for each front/rear pair.
- Time alignment for each individual channel.

Will the amp crossovers be sufficient to run an active front stage using the front RCA's for tweeters and rear for woofers? I am concerned with the quality of the crossovers and the 12dB slope?

I want to do this so I can separately purchase my woofers and tweeters for a "custom/DIY" front stage with the likes of Peerless or Seas woofers and a Vifa tweeter. This will save money by not purchasing a premade passive crossover network, and allow my to buy premium drivers for a good price.

Also running the tweeters and woofers on separate channels will allow me to use the DXZ935's 3 band parametric EQ separately on each giving me in effect 6 bands over the whole frequency range. Also I will be able to alter the time alignment between the woofer and tweeter to compensate for any mounting compromises.

Will the F540 inbuilt crossovers allow me to do this (and do it well enough to justify the effort)? Also this obviously introduces the cost of another amp to run the sub, instead of leaving 2 channels for bridging if I was running conventional splits and passive crossover.

hi
I run two of the amps u mention, the first bridged to provide 200watts rms for each of my focal midbasses, and then the other remaning mrvf540 used in 4ch mode to actively power a set of HLCD's and my focal tweets, i have the tweets x overd at 6khz and the horns x overd at 1khz while the midbasses are at 75hz and i couldnt be happier with the sound (well i guess if i had alot more money i could) i noticed the diff btw using my passive and running active is the clarity as higher volumes is better and i get better tunability, id go for it if ur HU is good. only downside is the need for more channels if u want to run say rears or three ways fronts, even two four channels cant allow me to run rears unless i dont bridge the front 6.5 inch drivers.

regards

Sounds like quite a setup! Are you using your HU to actively crossover, or purely the built in F540 crossovers?

The reason I ask is the DXZ935 only has crossover points at 50/80/120Hz for sake of integrating a sub, so I will be relying purely on the amp crossovers for the 2way front stage.

I'm worried a 12dB/octave slope might be too shallow and limit my choice of drivers. Do you know what slope typical passive crossovers use for 2way splits in the $500ish price range?

I'm thinking of forgetting about rear fill altogethor as the current rear speakers are shot and new rear's will cut into funds that could be spent on front. Do you miss the rears or do you prefer only the front stage? (To be honest I'm more used to a rear biased setup as in previous cars the simplest/cheapest/easiest option was to put good rear speakers in, but now would like to go a bit silly on a SQ based front stage).

i agree with u, i use the 04 CDA9835 and actively rtune from Hu so as to take advantage of variable slope function, but in ur case use it with a 12 db slope and just be careful where u xover even tho it may mean for good splits u cant get as low a x over point, at around 500 id say u would get 12-18db slope x overs, pay a bit more and get the hi grade 24db slopes, but with correct tuning u can get ur system sounding good and very clear with what u have and active, also i dont miss rears with the front so loud, especially with horns and enough power going to subs it a well balanced package, maybe ppl in the back seat dip out a bit of the SQ but thats the bad luck of it for them..

quite do-able. nothing wrong with 12dB/oct slopes. many high-end speaker manufacturers actually go with 6dB/oct slopes for reduced phase issues and smoother frequency response, but it depends on the drivers being used. for example, dynaudio use 6dB/oct slopes in most instances.

you haven't mentioned what drivers you're using, so i cannot recommend what settings may suit, but something like:

*BP the front woofer and use the 'rear' preouts: use the HP in the clarion say at 80Hz; use the LP on the F540 say at 1.5kHz; this creates a bandpass of 80Hz~1.5kHz
*HP the tweeters and use the 'front' preouts: use the HP in the amp, say at 1.5kHz; if the tweeters aren't top quality, then a higher setting will be required, say at 2~3kHz, although a 12dB/oct slope should mean 1.5~2kHz will be fine

i have a fully active 3-way frontstage and use 12dB/oct slopes, no probs.

Awesome I think this is a mission worth doing =)

As for the drivers, I'm really not sure and currently researching... have found this Peerless 4ohm woofer that might be a good option, have to decide on a tweeter. This will be a while away so I have plenty of time to decide.