crossover calculator accuracy

[pikkujöpö]

Hi

I would like to know how accurate are the crossover calculators?

The reason why I'm asking is because my 3way speakers have a separated (by wall)6,5" bass drivers with passive first order crossover.I was thinking to maybe use them with Jordan jx92s monitors in aprox.3l enclosure,the recomended first order crossover point around 112hz.

I thought that my bass drivers are crossed at 100hz but now I played with a calculator and it tells 85hz.(the Jordans go to 85hz in 8l closed box).

The bass drivers are 8 ohm with 15mh inductor and two parallel 470uF condensators between the - and + .I would like to know if my old bass drivers are really crossed at 85hz,or is it possible the calculators are not so accurate when the only parameter used is the impedance?

I'm planning to use the same bass driver with my old speakers(for movies) and later with Jordans(for stereo listening).Just switching between the two.So I'm trying to figure out how big boxes to make for the Jordans.Or new crossover to use with Jordans.?

I wish I had enough space for VT or MLTL boxes in my room.

[rabbitz]

The calculators are fine as long as you use the actual impedance of the driver at the crossover frequency and not the nominal impedance. You can get this impedance by measuring or have a look at the impedance plot on the manufacturer's data sheet which will be close enough for what you need.

[jomor]

the re accurate in theory, but they dont take into consideration various factors that are critical for a succesful design.


imho they useless . assuming we use the correct impedance value:

1) they assume that the driver's freq response is flat, which is not (for example the spl bump at the midrange that many woofers appear or the tweeter's bumps and dips due to difraction.

2) they dont take into consideration the drivers acoustic center offset

3) you cant do a baffle step correction using the standard filters the calculators offer

these mean that using calculators we ll get a questionable magnitude response, a wrong phase response ( = bad mids ) and no bass.

[pikkujöpö]

Thanks for the replys

The crossover is hopefully around 100hz then.I don't have the 3way speakers specifications anymore,but this is the info from other owners.

The manufacturer doesn't provide much information for this driver.

I will try first how the Jordans sound when useing these crossovers with the bass drivers.

By the way,should the crossover point of the bass drivers be when the jordans reach 0db or -3db.(the jordans run out of bass in small enclosures without the need of crossover).

thanks

[rabbitz]

Go for the -3dB on the Jordans and then play around.

A simple question was asked and a simple answer was given.... the fandangled xo software uses the same formulae as the calculators but of course they take more stuff into consideration. The calcuators should be ample for what pikkujöpö wants to achieve with a bit of testing. A good learning starting point and as he becomes more confident, then can move into the fancy stuff.