[Pez]

This topic makes me wonder, is it the passive crossover that full range guys hate? Or is it the woofer, mid, and tweet? Why is it that one would ditch oNe set of problems for (forgive me I mean no harm) a set of much worse ones? I really am curious why true FR guys do it the way they do?

I for one also do not like the sound of passive crossovers, but I went active 1st orders and SET with huge dynamics, tight bass and crystalline highs. Something that I have not heard from any system with a passive crossover and certainly not something I've ever heard from FR of any sort. Though I personally think passive comes closer than FR. Am i missing the point? Any feedback would be greatly appreciated.

I didn't want to highjack the other thread, so I thought I'd bring this topic to it's own thread.

Just a brief history, I have heard many single driver config in open box, sealed and even just a driver placed on a stand. The only time I ever really had a higher appreciation for any of these configs is at RMAF when I heard the Lowther fullrange at RMAF 2 years ago. Problem is, it was augmented by 8" woofers.

Any way, it's very likely that I just have never heard an excellent setup with fullrange drivers. I am genuinely curious and would like to start this thread to give me an idea of what FR does that nothing else does. If you posted responses in the other thread (which I have been keeping up with), please feel free to bring it over here.

[JLM]

Beyond the theoretical advantages (and some disadvantages), for me it boils down to coherency.  I listen nearfield and can hear the sound jump from woofer to midrange to tweeter.  I can hear how each produces sound differently.  No voicing differences or phase mistakes.  Ideal imaging.  As much as I like the extremes, the heart of music will always be in middle where extended range drivers thrive. 

[Scott F.]

<snip>

The only time I ever really had a higher appreciation for any of these configs is at RMAF when I heard the Lowther fullrange at RMAF 2 years ago. Problem is, it was augmented by 8" woofers.

Jason,

I assume you are talking about the Lotus speakers. If so, they used a pair of 15"ers to augment the bass of the Lowther rather than the 8s you mentioned.

I'm not so sure it is a "problem" unless you approach the FR/WB driver from a purist point of view. The upper end Lowther drivers (PM2A, PM5A) actually extend out to about 12-14k with fairly even treble. Enough so that you really don't need a tweeter. The great part of that frequency response is that they don't sound dull or colored like a few other FR/WB drivers out there.

The big drawback to Lowthers is their lack of bass. I've played them in OBs, back loaded horns and bass reflex enclosures. None of those delivered what I would consider quality bass. In turn a few of us have decided to augment our Lowthers with big woofers to fill in the bottom end. In my case it's a pair of 15s in BR enclosures. I'm pretty sure you listened to Jon VerHalen's (Lowther America) version of my speakers at last falls RMAF. He finally switched over to a BR enclosure after many years of prodding.

Using the PM2A on an open baffle above and a 15 below, you can create stunning sound by biamping and using an inexpensive active crossover. Heck, you could even do a passive XO at say 150-200Hz and make it sound pretty darned good.

The issue I have with the Lotus design (besides the ridiculous $120k price) is that they use digital EQing to achieve a flat response. That and I don't know if you noticed, they also use a helper tweeter on the back side of the baffle.



Now, digital EQing is fine (honest) but when a typical speaker designer approaches a new design, they want to achieve the flattest response they can without resorting to an EQ or heavy notch filters in the crossover. This is the way I approached my Lowther design. I use no EQing or filters of any sort. I simply use an active crossover rather than a passive. And honestly, I don't need any EQing. I get a pretty darned even response up and down the frequency chart. Sure, I don't get much above 14k but that's OK.

As JLM mentioned, it's all about coherency but I'll take it one step further. It's also about having no passive parts downstream of your amp. Passive crossovers suck the life out of music. Once you hear a WB driver done right, you will fully understand. Until then you can only hope for a minimally invasive sound from your passive XO.

IMO (and it is just that), I'm not sure we will see a true FR driver that can do say 40Hz to 15k (well) anytime in the near future. Most that come close are either (like the Lowthers) bass shy or colored (Fostex). Who knows though.

The one thing about my OB design, you need a big room to support them. They really like being 6+ feet out from the wall. Those monster woofs don't take kindly to small rooms either.

Ultimately, for about $5k you can do a complete build similar to what I've got. Use the 15" Servo sub. a pair of PM2As, buy a vintage analog XO and build an enclosure. In the grand scheme of things, that's not so bad. You can use anything from a 45 or 10Y SET on the top side to a Krell on the woofers. You have lots of options and all of them can sound stunning, far better than traditional monkey coffins (IMO of course).

[JLM]

Using just one driver another big advantage that is often overlooked is that the speaker by definition is active (one amplication channel per driver).  The greatly improved dynamics, flat frequency response, and upbelievable bass from going active makes a giant difference.


Scott,

I agree about having passive components between amps and drivers, thats why I use DEQ.

Check out Fostex F200A drivers, definitely not your typical Fostex driver.  Medium efficiency, but rated 30 - 20,000 Hz at 8 ohms with the magic of AlNiCo.

[chrisby]

Jason,

I assume you are talking about the Lotus speakers. If so, they used a pair of 15"ers to augment the bass of the Lowther rather than the 8s you mentioned.

I'm not so sure it is a "problem" unless you approach the FR/WB driver from a purist point of view. The upper end Lowther drivers (PM2A, PM5A) actually extend out to about 12-14k with fairly even treble. Enough so that you really don't need a tweeter. The great part of that frequency response is that they don't sound dull or colored like a few other FR/WB drivers out there.

The big drawback to Lowthers is their lack of bass. I've played them in OBs, back loaded horns and bass reflex enclosures. None of those delivered what I would consider quality bass. In turn a few of us have decided to augment our Lowthers with big woofers to fill in the bottom end. In my case it's a pair of 15s in BR enclosures. I'm pretty sure you listened to Jon VerHalen's (Lowther America) version of my speakers at last falls RMAF. He finally switched over to a BR enclosure after many years of prodding.

Using the PM2A on an open baffle above and a 15 below, you can create stunning sound by biamping and using an inexpensive active crossover. Heck, you could even do a passive XO at say 150-200Hz and make it sound pretty darned good.

The issue I have with the Lotus design (besides the ridiculous $120k price) is that they use digital EQing to achieve a flat response. That and I don't know if you noticed, they also use a helper tweeter on the back side of the baffle.



Now, digital EQing is fine (honest) but when a typical speaker designer approaches a new design, they want to achieve the flattest response they can without resorting to an EQ or heavy notch filters in the crossover. This is the way I approached my Lowther design. I use no EQing or filters of any sort. I simply use an active crossover rather than a passive. And honestly, I don't need any EQing. I get a pretty darned even response up and down the frequency chart. Sure, I don't get much above 14k but that's OK.

As JLM mentioned, it's all about coherency but I'll take it one step further. It's also about having no passive parts downstream of your amp. Passive crossovers suck the life out of music. Once you hear a WB driver done right, you will fully understand. Until then you can only hope for a minimally invasive sound from your passive XO.

IMO (and it is just that), I'm not sure we will see a true FR driver that can do say 40Hz to 15k (well) anytime in the near future. Most that come close are either (like the Lowthers) bass shy or colored (Fostex). Who knows though.

The one thing about my OB design, you need a big room to support them. They really like being 6+ feet out from the wall. Those monster woofs don't take kindly to small rooms either.

Ultimately, for about $5k you can do a complete build similar to what I've got. Use the 15" Servo sub. a pair of PM2As, buy a vintage analog XO and build an enclosure. In the grand scheme of things, that's not so bad. You can use anything from a 45 or 10Y SET on the top side to a Krell on the woofers. You have lots of options and all of them can sound stunning, far better than traditional monkey coffins (IMO of course).

Actually, I think the Lotus use Feastrex - up to an including the Field Coil models (whose driver pricing makes Lowther seem like a Parts Express TB clearout). 

http://www.lotusgroupusa.com/Granada.htm

I couldn't agree more on the potential for well executed small OB with something like a Lowther and woofer to outperform "conventional" commercial monkey-coffins - but as you point out - damn if the laws of physics and the size of rooms or other domestic factors to which many of us have to adapt don't get in the way 

And of course the Lotus design isn't the only OB design incorporating digital wizardry to achieve desired in room response and  "tunability"  - e.g. Emerald Physics

http://www.emeraldphysics.com/ 


but of course, you probably knew all that already


If you haven't done so already, you might want to taste test some of the new offerings from Mark Fenlon.  Sure his engineering willingly pays a stiff sensitivity penalty compared to the Lowthers, AER, Supravox, Feastrex, etc., but they deliver a helluva lot of performance for less than the sales tax on any of the above.   


and as JLM noted, not all Fostex are coloured and bandwidth limited - the F200A ain't no FE126

[Scott F.]

Check out Fostex F200A drivers, definitely not your typical Fostex driver.  Medium efficiency, but rated 30 - 20,000 Hz at 8 ohms with the magic of AlNiCo.

You're right, I really need to track a pair of those down and play with them. Those and the Fenlon's chrisby mentioned. Who knows, maybe someday soon we'll get there (30-20k) without giving up too much...then again, maybe we are and I haven't realized it yet 

Those other drivers I've been really impressed with over the years are the Supravox. They seem to have the opposite problem of the Lowhters, they roll off on the high side (about 8k) and need a tweeter on top. The pair I heard in a rear loaded horn were pretty memorable across the range they provided. Not much coloration across the spectrum at all. They were only missing some sparkle and air on the top.

[planet10]

Who knows, maybe someday soon we'll get there (30-20k) without giving up too much...

Mark's bigger Alpairs (7, 10.2, 12) come pretty close and with a lot of finese (the lesser ones with a bit less finese) -- depending on box, mid 30s or 40s, out past 20k. Limited dyanmics & ultimate volume due to limited cone area, but for many, that isn't someplace they usually go. And can always be greatly remedied by following Toole's advice... 80 Hz up, and the stuff below with multiple woofers (they usually need to be somewhere else than where the mains are).

dave