@audiokinesis wrote:
Sweet!
I really like your radiation pattern choice, it’s wide enough and consistent enough to give very good coverage of the listening area, but not so wide that you have an excess of early-onset reflections. And you will have a good directivity match between your woofers and the horn in the crossover region. Those big woofers in their bigfaced box will have useful pattern control probably down to the Schroeder frequency just from their sheer size.
Initially I bought the EV system with the smaller HP940 horn (it uses the same compression driver, the DH1A, regardless), and though I was offered the larger HP9040 horn at the time I feared it would "overload" the listening space and thus opted for the smaller horn. It became clear however that the HP940 horn didn’t load the very powerful DH1A driver (2.1 Tesla flux density) properly, sounding too hot in the upper presence region, whereas the HP9040 horn made for a much smoother, more fully fleshed out, relaxed and physical presentation.
It goes to show that while the larger horns might at first be deemed crazy, too up front sounding, overloading the room etc. (a classic case of "listening" with the eyes or one’s preconceptions), they’re typically the more well-balanced, relaxed and smoother sounding variants over the smaller ones. A bit like large panel speakers on steroids.
It was apparent as well that the larger horn made for a more coherent and of-a-piece sound, which confirms a good directivity match at the crossover to the woofers, as you point to. Indeed size matters here :)
For instance, most manufacturers make cone-n-dome speakers that have wide radiation patterns, so they are already getting a lot of reflection energy out into the room. They may not see much potential benefit to adding more reflection energy even if it is corrective. (The idea that rear-firing energy CAN be corrective may not be very widespread.)
I’m wondering if the typical "cone-n-dome" speakers are so popular with the manufacturers from the perspective of a deliberate design choice or more a reflection of a smaller size factor being a better business proposition? Perhaps I’m assuming more than wondering here, but I’m guessing power response and reflection field isn’t at the top of their agenda, or at least something they’re less likely to be successful with the typical designs choices of front firing only, direct radiating smaller woofers/mids and dome tweeters.
Then there’s the question of cost/benefit: Even if there is some benefit from adding rear-firing drivers, could the same amount of money spent elsewhere make a bigger improvement? And, perhaps the most practical question: Will having rear-firing drivers make a worthwhile difference in sales?
I’m not sure most manufacturers even considers the alternative of adding rear firing drivers (with the exception of tweeters, perhaps, which seems to be about something else than getting the reflection field right per se).
Are your speakers "active", crossover-wise?
Yes they are, with the exception of the JBL Alnico tweeters that use a simple 1st order high-pass filter with Mundorf Silver/oil caps coming in at ~11.5kHz. The Alnico’s are 105dB sensitive, but match wonderfully with the ~110dB large EV horn with a rather natural sloping here - indeed a lucky match. I don’t like the top end to come across as "lively" but rather prefers it blends in smoothly as a natural extension of the mids. I’m more of a "based around the midrange"-sound kinda guy, even though I’m not british :)
Obviously in my case the configuration is outboard actively with a Xilica DSP and the great british MC² Audio amps (S800’s for the EV’s, vertically bi-amped, and a T3500 for the subs).
What are your thoughts on active configuration, and is it something you have considered for your own designs?