Finally I’ve found some time to publish the Revelation Two – Monitor MkII loudspeaker. Actually it has been more or less finished for some time now, but other things have come in between like work and some family quality time! 🙂
The Revelation Two – Monitor MkII loudspeaker uses two of my favorite driver units, the ScanSpeak 15W/4531G00 mid-woofer and the ScanSpeak D3004/660000 tweeter. Even though these drivers are quite expensive, I think they are worth its price and they deliver top notch sonic performance.
The ScanSpeak 15W/4531G00 is one of the smoothest driver I’ve ever measured and is completely without any nasty cone break-ups and it’s very well suited for shallow sloped filters like the second-order Linkwitz-Riley I’ve used in this design.
The D3004/660000 tweeter has a low distortion profile and is also a perfect match for the second-order cross-over filter I’ve used in this design.
I’m a fan of non-complex cross-over filters and I cannot say that this cross-over is simple if I count the filter parts needed for it, but it isn’t really that complex as it may look like at the first glance.
The mid-woofer cross-over uses a couple of response shaping circuits and the tweeter uses a “Ladder Delay Network” circuit to time delays the tweeter so its acoustic center off-set matches the mid-woofer and makes a perfect phase behavior around the cross-over frequency with minimal phase distortion.
Besides that the cross-over is very simple with a first order filter for the mid-woofer and a second order for the tweeter together with a LCR circuit to flatten the impedance peak at the tweeters resonance frequency.
The loudspeaker can be built using two different enclosure volumes and port tunings, 11 liter or 14 liter enclosure. One thing to remember is that the baffle dimensions and driver unit layout must remain the same in both options. Build the larger enclosure by making it deeper in order to accommodate the needed extra 3 liters.
In the published design I’ve used the Parts Express 11 liter curved enclosure, which works well and looks great. Both enclosure options have great bass response. In this design I personally prefer the smaller enclosure due to its quicker mid-bass response. The larger one is an option for those who want to dig a few Hz lower.
I’m very happy with the end result and in this design I think managed to use both these very fine drivers to its full potential. I might also if anyone whishes release a “Beryllium” tweeter variant using the very nice ScanSpeak D3004/664000 tweeter?
For further details see: Revelation Two – Monitor MkII
Regards
/Göran