# Crossover topology for 3.5 way

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#### Sony

I am somehow lost, therefore decide to ask the help of the experienced members.
It's hard to control all the factors, like time and phase alignment. At this point I just want to save time and money and go for a safe solution that will probably work well and does not require hard tuning.

The project:

3.5 Way floorstanding
xo points (2nd order):
- Tweeter: 4KHz- (5KHz- if 1st order)
- Midrange: 1-4KHz (2-5KHz if 1st order)
- Woofer 1: 0-1KHz (vented)
- Woofer 2: 0-200Hz (vented)

I haven't tried these yet:
- 12dB paralell Butterworth
- 1st order paralell or series
- Mixed orders

From these, what do you believe would be the most likely to "fit and work well" topology?

Thks & rgrds

Well, IMHO, you are lost because you are barking up the wrong tree.
Wanting to avoid hand tuning is a worthy objective, but then to combine this with an objective of a 3.5 way passive crossover (!) is begging for disappointment. Maybe you could back up a bit and tell us what your skills and project goals and budget are and we could suggest an alternative route.
BTW, even if you are stubborn and insist on going this route nobody can help you because you haven't specified drivers or driver parameters.

#### mastertech

The project:

3.5 Way floorstanding
xo points (2nd order):
- Tweeter: 4KHz- (5KHz- if 1st order)
- Midrange: 1-4KHz (2-5KHz if 1st order)
- Woofer 1: 0-1KHz (vented)
- Woofer 2: 0-200Hz (vented)

i think your system is not 3.5 i think it is 4way pseudo
make it 4way make a crossover at 200hz 4way sounds better than
3.5 keep the system in good order

this suggestion is super

#### Sony

Thanks for the tips.

Concerning the 3.5 vs. 4 way, since the last frequency xo is very low (200Hz), I thought it would be best to avoid the complexity of a second band pass (on the woofer), and play with the enclosure/port tuning making its freq. response start a slow drop at 200Hz.
With a large chamber the woofer handling a 0-1000Hz signal results in a 100-1000Hz response, with a gentle natural drop starting at 200Hz.

The other woofer (0-200) uses a separate chamber with a pipe-horn about 1.5 meters long. Response is about 18Hz (-6dB).

I have found excelent software for enclosure design but the only crossover design software I've found were calculation sheets for the classic crossover types.

Drivers are:

1 x LCY 130 (well known by diyaudio members)
1 x Beyma MC115
2 x Beyma 8Woofer-P

#### jomor

Sony said:
[I have found excelent software for enclosure design but the only crossover design software I've found were calculation sheets for the classic crossover types.

calculation sheets are far from reality. you have to be lucky to make a 2 way to work properly (smooth magnitute transition at the x frequency, less than 10 degrees phase difference around the x frequency). In fact thats not that easy even when measuring and simulating. Its almost impossible to make this happen with calculators on a 3.5 ways, you need to measure and simulate and to spend too much time for fine tuning. A 3.5 way is not a plug and play project, in needs lots of developing time, if you dont have the appropriate tools and experience, it would be wiser to go for something more simple, which will please you sooner. Good luck anyway

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