This is basically a follow up to the Tuesday Tech Talk that I just did on these. You can see it here:
https://www.youtube.com/watch?v=arYwrAtcJZY&lc=z23rdb3bwszjjb1g104t1aokgkbbp5vt3wem3sbhfd5lbk0h00410.1574955117800485They look nice, but what do we really find under the hood?
I'll start with all the factory measurements.
The on axis response shows some curves and a top end that is about a db hotter then the rest of the speaker.
And the bi-wiring on the back side make shooting individual responses pretty easy.
They aren't completely in phase at the crossover region on the tweeter axis (as this was taken), and there is a clear dipped area in the crossover region. Also each driver struggles to reach the other a little bit.
The woofers response was pretty rough. There was a huge spike at 6kHz showing a lot of ringing. This is typical of a lot of metal cone woofers.
So the stock crossover used an aggressive second order curve to get the peak out of it. Unfortunately it humped up the response in the 700 to 800Hz range.
The tweeters response looked pretty good. The gain down low is due to the wave guide (horn).
The vertical off axis shows the drivers getting a little further out of phase as the microphone moved up.
As the microphone moved down the drivers stayed in phase a little better over a pretty good range. So flipping the stock speakers over or tilting them back will help.
And the horizontal off axis looked great but was still a reflection of the bad on axis response.
The spectral decay looked pretty good.
The impedance was a bit of a mis-match. And there are a couple of cabinet resonances that are showing up in the impedance curve at 25Hz and 55Hz.
Okay, so what did I do to them? Well as we can see here, I smoothed out the on axis response.
Check out the new crossover curves.
I tried a number of different crossovers and orders to try to improve the phase relationship of the drivers. It is not so easy when the tweeter is already further back in time than the woofer. So I wound up using first order filters on them. That worked great except for the fact that the woofer needed a lot of help getting rid of the huge peak up top. So I designed a notch filter to knock that peak out. It was a pretty aggressive filter, but it worked great.
So in the end there were only three parts in the woofer circuit and only three parts in the tweeter circuit. That's only one more part than what was on the factory crossover.
The vertical off axis now looks pretty good. The response stays pretty flat until getting up really high. The green line is 12" up at 1 meter.
The new horizontal off axis looks great. This is a super smooth roll off in the off axis.
The spectral decay is still super clean, but balanced.
And the impedance is a little more balanced. I could go in and add an impedance trap to really flatten out the load, but I am trying to keep this a budget level upgrade.
So that's the measured data.
I am going to offer this as a complete upgrade that address other issues as well. The upgrade will include MUCH higher quality parts than what was used in them originally. I will include high quality internal wire that is four 9's pure solid core Copper with polyethylene coating. The upgrade will include a set of tube connectors, and a sheet of No Rez. The total for everything is $209 plus shipping.
