OP, can you describe or define what "high output" is in this context? Assuming it's an SPL value.
True high-end Speakers need a midrange
To be clear, I don’t mean expensive, I mean high performing.
I recently built a new center speaker for my home theater and as I was comparing/contrasting design alternatives between a variety of designs, everything from expensive DIY designs to Wilson, Legacy, ATC and Focal and others the thing that stood out the most was this:
- You can’t get high output AND low distortion without a midrange driver.
I say this as a person who has had pretty good success with 2-way speakers and really admire 2-ways from Fritz and others, but when push came to shove, there was no way to make a 2-way with very high output AND low distortion AND excellent off-axis performance without a midrange driver.
You can push many tweeters down to 2kHz or even a tad below but it is very hard to find a tweeter that will do so with low distortion at high volume. On the other hand there are many 1" domes which will perform excellently when crossed over at 3 kHz or higher even when driven hard, things you don’t see from a frequency response plot, or really any measurements from Stereophile which never plots dynamic range charts. It’s not just about the frequency response and imaging, sometimes it is about doing all of that under pressure that matters.
Similar, complementary issues are true for the woofer in a 2-way design. First, good mid-woofers with good frequency responses through 2-4kHz are expensive, but as you push the crossover up 7" drivers and larger have to beam, right in the middle of the midrange. Instead of a wide open sound stage you can hear anywhere they restrict where you can sit.
In a large, full range speaker you can push your design for high output even further by going with a 5" midrange for instance. Not quite as wide as the 4" counterparts but lots of power handling and plenty of overlap with the tweeter and woofers.
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@carlsbad2 ...Well, that's certainly the 'best presented Xover' I've seen in awhile...(most look like 'pre-re-hab' and not very...'presentable'.) ... ;) Kidding aside, tho'....why? Does admiration make it perform better? We note the layouts and wiring in various other pieces of equipment, so....?🤷♂️ |
*L* So...we're stuck in the middle, trying to find the speaker(s) whose issues dovetail to our imperfections....and those of the items we employ.... Kinda cynical, but....'splains why we expend so much time and cash trying to find that...symbiotic stasis....learning to love/hate the love/hate formula....*ow!* |
@erik_squires wrote:
This rings true with direct radiating dome tweeters in 2-way designs, but when you load a fitting, relatively low fs down tweeter with an 8-10" waveguide you can lower the crossover to below 1kHz and have rather flat power response at the crossover, while also relieving the dome tweeter in its lower band (even crossed that low) to such an extent, that the real limitation in output is more likely to be the woofer/midrange driver (example: S.P. Technology’s Revelation speakers (sadly discontinued) sports a ~10" waveguide on a 1" dome tweeter and two 8" SEAS woofer/mids in a d’appolito configuration, and they’re true full-range speakers down 20Hz. They might be a standout, but nonetheless they’re 2-way, full-range and no less SPL capable than many comparably sized 3-way designs). Another advantage here is that neither an 8, 10 or even 12" woofer/mid would see no significant beaming issues crossed below 1kHz. With a curved waveguide profile (to save diameter size) that doesn’t amplify linearly it does typically equate into a more complex crossover design (active config. would come in handy here), but if size isn’t an issue you can have yourself a fairly straightforward approach. Horn-loading a compression driver makes for an even more powerful combo compared to using a dome tweeter, and maintaining a 2-way design becomes a matter of finding the proper balance combining lower range energy at a given crossover point with upper end extension. Using a 4" diameter compression driver - while having excellent lower range output in a fitting horn and very low distortion numbers even at prodigious SPL’s - will be a challenge above ~10-15kHz, but with a proper motor structure in particular can alleviate severe drop-offs here. Myself I find crossing 15" woofer/mids in the 600Hz range to large format constant directivity MF/HF horns to be very well sounding, and the dispersion pattern match at the crossover between the woofers and horn is excellent. The EV compression driver sports a 3" titanium diaphragm with a pre-fitted 1.4 to 2" exit snout adapter. Flux density sits a 2.1 Tesla, so a large horn is necessitated to properly load such a powerful driver. In any case this combo handily combines very high output with very low distortion - even more readily so with the main 15" woofers high-passed above 80Hz, but that’s trivial in this particular context. Also worth mentioning here is the advantage of having a single point source from ~600Hz on up, and thus while augmenting with subs for an effective 3-way design for all intents and purposes what’s at hand is 2-way. |
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