Crossover Nightmare/Sleepless Nights

[ChrisR1983]

Hi Guys

I'm hoping for some assistance.

I'm building my own set of 2-way loudspeakers based on a design by Wilmslow audio.

I'm at the stage now where I think that my speakers are about done but I have concerns about my crossovers and I'm hoping that you guys can clarify a few things.

I've attached the crossover design, the cabinet is based on the Wilmslow Audio Pheonix cabinet, the drivers are Scan Speak 8531-G00 and D2904/7100.

A few questions if I can (I'm no electronics expert):

The polarity on the tweeter section, is it really reveresed compared to the woofer?

Is the crossover design any good?

If I have wired the crossovers incorrectly, what effect could this have on my amp, drivers, crossover components, etc?

Does anyone know any good articals on crossover assembly?

I'm sure there are more questions but the above should be a massive help!

Thanks

Chris

 

[kstrain]

Short answers

Hi Guys

The polarity on the tweeter section, is it really reveresed compared to the woofer?

Is the crossover design any good?

If I have wired the crossovers incorrectly, what effect could this have on my amp, drivers, crossover components, etc?

Chris

Yes, the polarity reversal is deliberate. (You can search for the reasons on the forum.)

No, I doubt that it is much good (by my taste). I'd certainly not like the balance. But it is best to judge yourself - it could be exactly what you want.

Best just to wire it correctly. Check each connection with a continuity tester. If you are still uncertain you could apply a 1.5V battery briefly to the speaker inputs and you should hear a thump from the woofer and click from the tweeter (as the connection is made, and again when it is broken). That won't do any damage (and you should see that the woofers at least have the same polarity).

Good luck.

Ken

 

[HiFiNutNut]

When you wire up the XO connected to the drivers, use a Multi-metre to measure the resistance between the speaker terminals. If the reading is above 3ohm then you can feel safe to connect your amps, etc, and they won't do damage to your amps and your amps won't damage your drivers under normal circumstances.

 

[tinitus]

Hi Guys

Is the crossover design any good?

Chris

In principle it looks fine
At first glance it could look like it will sound somewhat thin, with a raising response
I dont know how you have done the response graphs
But if they are ok, it could appear as if you may be a bit short on BSC, which means compensating for loss of output below 500hz

BUT, on a second look it may be something slightly different

Looking closely it appears you may have a slight peak below xo point
I cant say, but might be caused by xo
If so, and the small peaking could be brought down, it would be easy to attenuate the tweeter a bit more, and you would get a more even response, and the BSC would also be ok, I guess

Impedance looks perfect, though indicates that your xo point should around 2.5khz, where as the response curve shows 3khz as xo point, which may be caused by the shallow "peak"

 

[tinitus]

MAYBE, try and remove the paralel resistor on tweeter attenuation, and maybe adjust the series resistor a bit
And you may need a slightly bigger series inductor on midrange, maybe not much bigger
AND, maybe a slightly smaller paralel cap on mid
Maybe

 

[ChrisR1983]

Thanks for all the comments guys. I tested the woofer using the battery method mentioned above and got the tell tale thump so I'm happy so far. Tonight, I'm going to rewire the tweeter (simplyy swap polarity) and do the multimeter test.

With regards to how good the crossover is this was designed for me by Wilmslow Audio. Given that I've spent about £500 on crossover components I'm going to give it a try. I suppose I can always tweek the components later.

I'll keep you all posted!

Thanks again

Chris