I did add the ressitsnc of the air core inductors. That's how I got above 3.9 ohm.
I'm just going to measure the tweeters and see how they do. I already have everything bought, and it was cheap, so I'll just wing this one. I'll porba my give it away to my brother when I'm done
Well that's good news. Once you start compensating the baffle, the added resistance might take care of your impedance difficulties.
Doesn't the baffle also have to get bigger to hold a bigger woofer?
While that's true it doesn't prevent the baffle step to apply. A bigger baffle pushes the BS down unless the driver starts to beam before the baffle step applies (often at 12" and up). No dispersion at that frequency, no baffle edge reflection. According to your speaker building history and experience I really expected you to know that. Especially since your XO thread is pinned up for newbies to follow. It's probably time to update it.
For the woofer, I'd play around with some notch filters (series LCR, in place of the 100uF you had at the start) to try and get rid of the peak around 5kHz. Possibly drop the 1.2mH inductor altogether, as the notch should combine with speaker response to produce a roll-off on its own.
For the tweeter, keep the capacitor and size it get roughly the right amount of overlap, and do listening tests with a small selection of different series resistors for padding, to get the right bass/treble tonal balance.
Don't get caught up in the race for frequency flatness, because it's not even a good measure of "good sound". It's just one indicator of many. You still need to manually plug components in and listen to every change.
For the tweeter, keep the capacitor and size it get roughly the right amount of overlap, and do listening tests with a small selection of different series resistors for padding, to get the right bass/treble tonal balance.
Don't get caught up in the race for frequency flatness, because it's not even a good measure of "good sound". It's just one indicator of many. You still need to manually plug components in and listen to every change.
Yes, that's not the impedance but the frequency response.
I think he meant that the impedance is low in that range and causes the dip in the FR.
Try increasing the coil and reducing the capacitors from woofer filter. Adding a small capacitor (eventually series with a small resistor) in parallel with woofer coil to create a notch at ~5Khz will attenuate the peak in woofer response.
That's not an impedance dip. That graph is the transfer function. Essentially what your crossover components are doing to attenuate the response. and therefore shape the final acoustic response (top left) of the drivers which sum to the overall system response.
The bottom right is your impedance by frequency. If you are using a solid state amplifier, then a "rule of thumb" I've seen from others is to keep the impedance phase to <= 45 degrees. A flat impedance does this, but having peaks in your impedance isn't a problem for many sold state amps, as long as the impedance phase isn't swinging wildly to extremes (e.g. >= 60 degrees)
I will pull the impendence off the actual driver soon. Will post up when I have it.
I have some other things to get to this week.
Has anyone EVER seen a driver's stated Thiele small parameters off this far? Green line is with stated specs. The rest of them are what I actually measured. I added 9 grams to the cone.
I am attaching the impendence measurement so you all can see for yourself.
This is so far off I feel like I did something wrong. But I know I didn't...
I am attaching the impendence measurement so you all can see for yourself.
This is so far off I feel like I did something wrong. But I know I didn't...
Attachments
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Did you break in the driver? If so how? You need to wait briefly depending on how long / hard you break it in to let the voice coil cool and reduce resistance due to heat.
Some driver manufacturers use a higher level drive voltage (power) for TSP measurement (even though they are small signal parameters!). For example, I can never get my SB Acoustics drivers to measure as per factory via DATSv3.
Also - I believe delta compliance (known sealed box volume) is more accurate than added mass for TSP measurement, but whether it can make up for that discrepancy, I'm not sure.
Some driver manufacturers use a higher level drive voltage (power) for TSP measurement (even though they are small signal parameters!). For example, I can never get my SB Acoustics drivers to measure as per factory via DATSv3.
Also - I believe delta compliance (known sealed box volume) is more accurate than added mass for TSP measurement, but whether it can make up for that discrepancy, I'm not sure.