RS3000 Crossover Network with 8 ohm driver

[leosep]

Can i use a infinity RS3000 Crossover Network with a 8 ohm driver? I think that the RS3000 is 6 ohms.

 

[picowallspeaker]

Hi,
the woofer must be 4 Ω and the tweeter 8Ω , thus giving a 'nominal' 6Ω
impedance . So if you are using an 8Ω woofer you should double the value of the lowpass inductor to get the same crossover point.

 

[leosep]

Oh thanks for your response, but lets say that i already have the 8 ohm woofer and tweeter and the 6 ohm crossovers.

 

[picowallspeaker]

The 6 Ω value is given by the manifacturer for convention: it tells you and awares you that it's not a 8Ω speaker nor a 4 Ω one. You can consider the 6Ω as the average impedance of the whole speaker, being composed by a 4Ω woofer and a 8Ω tweeter; the value of the lowpass inductor is calculated for the 4 Ω woofer ; the highpass net is calculated for the 8Ω tweeter .
Using an 8Ω woofer with that inductor would shift the crossover frequency higher

 

[system7]

Such a vague question does have a vague answer, as picowallspeaker is saying.

Let's be more definite. Presumably your original 4 ohm polycone woofers have rotted foam surrounds. You have some (unspecified) 8 ohm units to replace them.

This needs a bigger bass coil for sure. You will also need to increase the input resistor to the tweeter filter to reduce its level to match.

Something like 1mH, 10uF and 1 ohm on the bass filter. Try around 6 ohms wirewound on the treble filter input to match levels. Shouldn't be too bad.

I would reckon these speakers need to be mounted close to a wall. Not much bafflestep there. The 10uF value might need some tweaking smaller down to 6.8uF. Hard to say, because it depends on the woofer, but I'd start with 10uF.

 

[picowallspeaker]

I owned a pair of RS5000 ( sheesh! They were outrageously expensive at the time ) and when the foam started to rotten...well, I think my DIY adventure started from there

 

[system7]

I notice there are a lot of refoam kits for these speakers. That might be an option.

Just for interest I simmed a speaker with 4 and 8 ohm W170 paper drivers to see how the crossover changed in Visaton Boxsim.

Make of it what you will, because polycones are different animals, but results below:

 

[leosep]

What about this one

Hi all, thank you so much for your responses, im new to this and im trying to understand what im doing hehe. And what about this crossover with this tweeter and woofer, specs attached:

Tweeter[FONT=Arial, Helvetica, sans-serif][FONT=Trebuchet MS, Arial]
[FONT=Arial, Helvetica, sans-serif][FONT=Trebuchet MS, Arial]2 7/8" acoustic dome tweeters[/FONT][/FONT]
[/FONT][/FONT][FONT=Arial, Helvetica, sans-serif][FONT=Trebuchet MS, Arial]Rating 50 watts RMS / 100 watts peak
SPL: 96dB @ 1W/1M
[/FONT][FONT=Trebuchet MS, Arial]Frequency response: 1.4-24KHz[/FONT]
[FONT=Trebuchet MS, Arial]I think is 8 ohms


Woofer[/FONT]
Rubber surround
1" voice coil
15.6oz. magnet

Specifications:: Power Capacity: 50W/100W RMS/peak
Sensitivity: 87dB (W/M)
Impedance: 8ohm
Re: 6.7ohm
Le: 0.59mH
Frequency response: 55Hz~17KHz
Fs: 55Hz
Qts: 0.40
Qes: 0.51
Qms: 1.87
Vas: 10.04 (liters)
Xmax: 2.0mm

Dimensions:Overall frame diameter: 5.14"
Required cutout: 4.21"
Mounting depth: 2.52"


[/FONT]

 

[leosep]

anyone?

 

[picowallspeaker]

Find a cheap 4Ω woofer and stick it there !
Possibly before the choice try some
What about the tweeter ? if the crossover is set for an 8Ω tweeter, find a suitable one.
make it be 3 dB louder than the woofer, but limit the choice to medium or low sensitivity tweeters .