2 way

[kategra84]

Hello,

I will build an loudspeaker with Monacor SPH-170 (18.5 centimeters outer diameter) woofer and Monacor DT-25N tweeter (6.6 centimeters outher diameter).

What is the formula for calculating the maximum distance between the centers of the drivers?

The active crossover frequency is 3410 Hz / 24dB Linkwitz-Riley.

I've searched over the web and found this formulas :
1. max distance = wavelength of crossover frequency / 3.14 / crossover frequency
2 max distance = wavelength of crossover frequency / 2

but i guess both are wrong, because the length of the wave is :
150000.00 meters for 2000 Hz
88235.29 meters for 3400 Hz
11.11 meters for 27Mghz
2.08 meters for 144Mghz

Does any one know the right formula?

[picowallspeaker]

Hi ,try to keep them as close as possible ,to simulate a 'point source' .
I've got a Secret Formula that gives you the length of a wave.
It's sound in air velocity (344 m/s ... ) / the frequency.
The Seconds misteriously disappear in that equation ,and you have only the Length !!!

[AllenB]

@ pico, what chance do people like me have when you keep withholding the formulas

@kategra, it's light that travels at 300Mm/s

[Helmuth]

Originally Posted by kategra84

Hello,

What is the formula for calculating the maximum distance between the centers of the drivers?


Does any one know the right formula?

Calculate wave length = (344m/s)/frequency = wavelength in meters

place them is close as possible to reduce lobes. Within wave length signal is coupled and will gain each other.

[bjorno]

Originally Posted by Helmuth

Calculate wave length = (344m/s)/frequency = wavelength in meters

place them is close as possible to reduce lobes. Within wave length signal is coupled and will gain each other.

Agree...See the picture using 'Tolvans' Xdir program:

b

[kategra84]

Thank you. I built the loudspeakers, 14.3 cm distance from center to center; i also changed the XO frequency to 2600 Hz.

I implemented a Baffle Step Compensation filter in my active XO, but i think i got it wrong, i no longer find the web page (searched in browser history, the web all day and night ) with the examples different ways to implement the BSC using different opamps circuitry (inverting, noninverting, etc).

That web page also provided the formulas to calculate the component values, gain, corner frequencies.
I accidentally threw away the paper on which i copied the inverting circuit and made the calculations.

I used R1=680 ohms, R2=1 Kohm, R3=4.3 Kohms , C1=220nF

From what i remember it should have an 3-4 dB gain at ~100 Hz with a gain of 0 db at ~450 hz.
But now i am not sure any more, i think the speakers are sounding a little to thin, music sound good if boost the bass 2-3 db in my Audigy2 eq panel.

Does anyone have the formulas for this schematic?

[kategra84]

I changed R2=2.5 k and R3=820 ohms and now it sounds great!