I recently got some speakers and possibly the most interesting ones are these Dali 700's. Could not find much information about these tho.
Anyway my very first impressions was that there must be something horribly wrong. Bass was ok, but midrange was quite peaky/one noteish and there was also lack of highs - as well as bad comb filtering. I got heavy listening fatigue after two songs! Whats going on? These are equipped with very high quality drivers: Vifa P25WO, Wifa D75MX and Vifa D25TX tweeters.
It is shame they ruined good drivers with bad crossover design (if you ask me). I took some quick measurements and there it was - same issues were visible. Took the crossovers out and drawed it to my crossover simulator software:
And here are drivers measured, with original crossover:
Pretty much matching my simulation. After that I simulated my own crossover as a starting point for designing new crossovers. Things are now looking much better at least in simulation!
Lower crossover freq is too low here for D75MX, so I finally crossed it at 900Hz / 4000Hz. Also the woofer had rising response toward the 1kHz so had to make some adjustments there too and added Z-network. Here is the measured response from woofer and mid together (some treble leak), good enough at this point.
Finally made some adjustments for mid/high section for a good transition and phase match and oh man these speakers are sounding so sweet! I actually kind of like that Vifa 3" dome midrange, it just makes something right what so ever. It has 1.5 litres enclosure, filled with wool. At this point I just need to listen and listen these to find out if they are good or not 🙂
Response from my listening position (bad room acoustics making bad things for upper bass response). But overall I'm very satisfied now 🙂
And the speakers as they are!
Feel free to give some further advices 🙂
Anyway my very first impressions was that there must be something horribly wrong. Bass was ok, but midrange was quite peaky/one noteish and there was also lack of highs - as well as bad comb filtering. I got heavy listening fatigue after two songs! Whats going on? These are equipped with very high quality drivers: Vifa P25WO, Wifa D75MX and Vifa D25TX tweeters.
It is shame they ruined good drivers with bad crossover design (if you ask me). I took some quick measurements and there it was - same issues were visible. Took the crossovers out and drawed it to my crossover simulator software:
And here are drivers measured, with original crossover:
Pretty much matching my simulation. After that I simulated my own crossover as a starting point for designing new crossovers. Things are now looking much better at least in simulation!
Lower crossover freq is too low here for D75MX, so I finally crossed it at 900Hz / 4000Hz. Also the woofer had rising response toward the 1kHz so had to make some adjustments there too and added Z-network. Here is the measured response from woofer and mid together (some treble leak), good enough at this point.
Finally made some adjustments for mid/high section for a good transition and phase match and oh man these speakers are sounding so sweet! I actually kind of like that Vifa 3" dome midrange, it just makes something right what so ever. It has 1.5 litres enclosure, filled with wool. At this point I just need to listen and listen these to find out if they are good or not 🙂
Response from my listening position (bad room acoustics making bad things for upper bass response). But overall I'm very satisfied now 🙂
And the speakers as they are!
Feel free to give some further advices 🙂
Indeed there is some similarities, as well as Dali 7 speakers. At least similar driver arrangement and same D75 dome midrange. I wonder what kind of crossover there was.. hopefully better 😀
The D75MX is a wonderful sounding mid when the rear chambering and crossover compliments its strengths. The rear clambering must be able to reduce the total Q through some extra mechanical dampening (sheeps wool), so it provides better control of low end rolloff characteristics. By that I mean the loss of diaphragm control at lower frequencies without external dampening throught the rear hamber allows diaphragm over excursion, permitting the driver to distort quickly compared to a critically dampened system. Further treatment of the primary system resonance by an electrical notch allows the limited xmax, which is the Achilles heal of this driver, to deliver the largest dynamic range possible from this driver. I suggest an 800 - 900hz LR2 HP for the best SPL capability and a LP of around 3.5k, but you may need different LP slopes to gel with your HF driver.
Measured the midrange at very close distance about 10cm just to find out if there is some nasties but cannot find or hear any problems. So far this dome midrange seems to be quite decent. Still looking for a time to make my last crossover modifications - tweeter needs some attenuation and I'm not sure if the woofer needs Z network or not.. otherwise the tweeter seems to be good.
Just for fun and comparsion - 4.5 inch cone midrange from Pioneer CS series 😀
Just for fun and comparsion - 4.5 inch cone midrange from Pioneer CS series 😀
Possibly the problem was an assembly line error?
In the original Xover and simulation they have a fairly decent and symmetrical notch, which is why i wonder if it was meant to be used with the mid reversed?
In your new design you have taken care of this aspect, and refined them even more.
Glad that you are enjoying them. 🙂
In the original Xover and simulation they have a fairly decent and symmetrical notch, which is why i wonder if it was meant to be used with the mid reversed?
In your new design you have taken care of this aspect, and refined them even more.
Glad that you are enjoying them. 🙂
Looking at the original FR of the individual drivers, there seems to be quite a bit of unwanted energy in the woofer between 4k and 20k and mid 12k(?) to 20k.
Did you manage to remove them in the new crossover?
What is the revised FR for individual like?
Did you manage to remove them in the new crossover?
What is the revised FR for individual like?
The main problem with the original connection is the wrong polarity of the individual speakers.
Bass and mid are subtracted at the crossover point. The solution was to change the polarity of the woofer. It would be correct to keep the bass and change the polarity of the other two.
Bass and mid are subtracted at the crossover point. The solution was to change the polarity of the woofer. It would be correct to keep the bass and change the polarity of the other two.