I’ve built the two prototype cross-overs described in my last post and I’ve started the listening evaluation of the two.
Before I describe my findings from the listening tests, I thought I should describe some cross-over simulations I’ve done for the two prototypes.
Both of the below simulations shows the frequency response optimized for max linearity at the 15deg off-axis measurement. A flat frequency response like this can in some loudspeaker designs sound a bit too bright and I will in my listening evaluation test different tweeter attenuations.
When I publish the new Sequence Two – Monitor design I will suggest different tweeter attenuations options in order to satisfy personal sound preferences and HiFi equipment matching.
These above four pictures show the “5deg backwards tilted baffle” filter design. The frequency response is very linear and smooth. The phase tracking between the individual driver units is great. When connecting the tweeter without reverse polarity you get as expected a -26db suck out in the frequency response centered at the 3kHz cross-over frequency.
These above four pictures show the “ladder delay network” filter design. The frequency response is also here very linear and smooth. The phase tracking between the individual driver units is even greater. When connecting the tweeter without reverse polarity you get a very deep -35db suck out in the frequency response slightly below the 3kHz cross-over frequency.
Both of the above simulations are optimized for a >2.5m listening distance.
This above picture shows a control measurement done at a 2m distance, 15deg off-axis and is valid down to 400Hz. The blue response is the tilted baffle version and the red is the “ladder delay network” version.
The control measurement confirms the simulated ones and the difference between the two filter options is very small. The main difference is that the “ladder delay network” version have +1dB output at 4kHz.
The suck-out centered at 1250Hz is some sort of cone edge resonance for the mid-woofer and it doesn’t look nice in measurements, but doesn’t hurt sonically.
The same goes for the tweeters rising frequency response from 15kHz and up. It may not look nice in measurements, but doesn’t hurt the performance of the treble.
The million dollar question is……. Which one of the filter versions sounds the best?
I will have to get back about that, since I need more time for listening evaluation before I make a judgment.