Modern controlled/constant directivity PASSIVE speaker designs?

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Jonathon Janusz

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I know I've said a few times when folks have been discussing the latest crop of active/DSP speakers from JBL that it is too bad that they didn't choose to make passive versions for those in the audiophile hobby that haven't decided to get on board the active/DSP train (setting aside for the moment the fundamental contradiction with the, "circle of confusion," concept that is foundational to the approach that made the JBL M2, etc. in the first place).

So as not to derail conversation focused on JBL's speakers as they are, I thought it might be worth asking if the collective has any recommendations on any currently manufactured speakers that do meet these requirements - focus on controlled/constant directivity/power response in light of modern, current research on speaker design, but in a fully passive crossover driven package instead of relying on DSP and integrated electronics (amplifiers) to get the job done.  Basically, I'm wondering if anyone makes speakers that follow the cutting edge modern engineering trends in something the average audiophile could buy, disconnect their speaker cables, plug those speaker cables into their new speakers, and get right to music listening.

I don't remember seeing such a thread posted lately (yet?) and nothing jumped out in a quick forum search.  Thanks for any thoughts!

macrojack

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I believe JBL meets your request with the 705i and 708i models. Same as active versions without the gizmology that you decry. Gedlee Abbey may also be considered but they may be rather large for this conversation.

Consider that the compression driver found in both active and passive 700 series JBLs moves them well beyond the performance characteristics of most any real studio monitor you can locate.

I do use the amps in my 705P but nothing else. I did not buy for the DSP, etc. and I do not use it yet. Maybe never will. What harm are these doing to my system?

Word has it that the active versions outperform the passive ones noticeably.

Jonathon Janusz

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According to JBL, the 705i/708i are not designed for use without their DSP.  They have a "single-wire" connection option (which I presume must be a basic passive crossover), but (again according to JBL) the speakers are meant to be run with their custom anecholic DSP correction provided by either a independent processor (BSS) or as part of a crown DSP-loadable amp.  What intrigues me about the -i speakers is that rumor I've read around online suggests that JBL says that biamping these speakers doesn't make much difference in performance compared to the single-wire hookup method, suggesting that a more robust (read: engineered without the assumption that DSP will be applied) crossover in these could be a viable option for a fully passive speaker if it were to exist. 

An interesting head to head comparison, I think, would be a pair of the -p versions against a pair of biamped (at around 250w/driver with a Harman amp) -i versions with the required JBL DSP to isolate the active crossover as the only appreciable difference between the two.  Even without using the adjustable features in the built-in DSP in the 705p, one must unavoidably use the built-in DSP-driven active crossover because it is what is feeding the internal amps.  In short, the -i is close but still not quite at the mark in this case.

This situation (JBL not making a truly, genuinely passive 7xx speaker) was more or less what got me to kick off this thread.

Thanks for giving me opportunity to flesh out where the idea where this thread came from!

JoshK

You are correct that the i version still use a file loaded into the BLU or the appropriate Crown amp(s).  I know, I own some.

The JBL 7 series are fantastic in that they bring about good engineering into a  reasonably affordable turn key solution, but they aren't exactly what you are after. There are other speakers and this thread would be a great place to exposite speakers that meet the characteristics of well designed speakers with the science we know today.

Let me first start off by pointing out a good reference on measurements of a lot of common speakers on the market using measurement techniques developed by Dr. Floyd Toole when he was at the NRC.

https://www.soundstage.com/index.php?option=com_content&view=article&id=16

He subsequently refined those measurements into the spinorama that the Harmon facility used when he was there.  He himself said that most of the info is there but not quite all.  Ok, good enough place to start.   At least they put forth the minimum amount of data needed to judge speaker performance which is still a boatload more than most speaker manufacturers provide.

One thing worth addressing is that I think Harmon have shown that wider directivity is preferred all else being equal (that whitepaper in the other thread reiterated such a point).  So speakers like the Revel Salon2 ($$$$) also hit all the marks of a good measuring speaker even though they aren't controlled directivity because of the super even off axis response and power response. There are reasons why one might wish to use controlled directivity and Dr. Geddes is a proponent of such.  However, I don't think there is consensus that it is absolutely necessary for ideal SQ.   I think this point is worth mentioning, but we can still discuss speakers that are controlled directivity.

Last I heard Geddes moved onto active speakers, but he may still provide passive versions, I haven't looked.   There are a number of DIY designs involving the SEOS waveguide that were designed with the same principles in mind but no one I know of has access to an anechoic chamber to confirm if they really hit all the marks, but at least we know they probably do above ~500hz or so, which is the most crucial part IMO.

I think Danley Sound Lab Synergy speakers probably hit most of the marks but have fairly narrow directivity.   

It seems as though a good chunk of the studio monitor crowd has addressed the controlled directivity and/or off axis performance as we are seeing waveguides on tweeters more ubiquitously that ever before but I don't have a lot of experience with this market.


JoshK

(setting aside for the moment the fundamental contradiction with the, "circle of confusion," concept that is foundational to the approach that made the JBL M2, etc. in the first place).

P.S. I don't wish to discuss this point here as it will derail the thread, but maybe we can discuss it elsewhere or in private.  I don't get this point at all.  The circle of confusion is term for the intellectual confounding of two vastly different things and only enlightens what the fundamentals should be for good speaker measurements regards of which speaker it is.   The M2 isn't unique in trying to acheive this goal at all. 

poseidonsvoice

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You are correct that the i version still use a file loaded into the BLU or the appropriate Crown amp(s).  I know, I own some.

The JBL 7 series are fantastic in that they bring about good engineering into a  reasonably affordable turn key solution, but they aren't exactly what you are after. There are other speakers and this thread would be a great place to exposite speakers that meet the characteristics of well designed speakers with the science we know today.

Let me first start off by pointing out a good reference on measurements of a lot of common speakers on the market using measurement techniques developed by Dr. Floyd Toole when he was at the NRC.

https://www.soundstage.com/index.php?option=com_content&view=article&id=16

He subsequently refined those measurements into the spinorama that the Harmon facility used when he was there.  He himself said that most of the info is there but not quite all.  Ok, good enough place to start.   At least they put forth the minimum amount of data needed to judge speaker performance which is still a boatload more than most speaker manufacturers provide.

One thing worth addressing is that I think Harmon have shown that wider directivity is preferred all else being equal (that whitepaper in the other thread reiterated such a point).  So speakers like the Revel Salon2 ($$$$) also hit all the marks of a good measuring speaker even though they aren't controlled directivity because of the super even off axis response and power response. There are reasons why one might wish to use controlled directivity and Dr. Geddes is a proponent of such.  However, I don't think there is consensus that it is absolutely necessary for ideal SQ.   I think this point is worth mentioning, but we can still discuss speakers that are controlled directivity.

Last I heard Geddes moved onto active speakers, but he may still provide passive versions, I haven't looked.   There are a number of DIY designs involving the SEOS waveguide that were designed with the same principles in mind but no one I know of has access to an anechoic chamber to confirm if they really hit all the marks, but at least we know they probably do above ~500hz or so, which is the most crucial part IMO.

I think Danley Sound Lab Synergy speakers probably hit most of the marks but have fairly narrow directivity.   

It seems as though a good chunk of the studio monitor crowd has addressed the controlled directivity and/or off axis performance as we are seeing waveguides on tweeters more ubiquitously that ever before but I don't have a lot of experience with this market.

All good points Josh.

I would like to state that the JBL 7 series and M2 are really completely well thought out designs and any manipulation thereof without the enormous assistance of an anechoic chamber and spinorama like measurements to produce passive crossovers for them is in and of itself...useless. What you get with JBL is the enormous amount of research and development for not just the tiny fraction of '2 channel audiophiles' (and we are certainly full of ourselves) but really the entire industry as a whole, especially the pro industry who have far more exacting requirements than the tweaky '2 channel audiophiles.'

Be careful for what you wish for as you can easily have worse performance (using an inadequately engineered passive crossover) than what these series of speakers are engineered for. Why mess with a good thing? The best "tweaking" you can do is choose your 4 channel amplifier of choice, get a London BSS processor, download Harmon's DSP for your 705i, 708i or M2. Done! For a fully passive design, you might end up spending more money and worse performance especially if you cannot perform competent measurements such as spinoramas, polar plots and the like. I used to think it was easy, but it really is not. It requires resources, patience and intelligence, all of which JBL has. Even KEF in their latest Reference 5 and Blade models show spinorama measurements, crediting Floyd Toole. I am very impressed and pleased to see that Floyd's work is being put to good use.

If I didn't own a pair of Geddes NA12's (the successor of the Abbey and yes, much better) and didn't refinish it as I have (please see the Enclosures forum for details), I would most likely be an owner of the 708 or M2 along with my swarm of multiple subs. Geddes, fwiw, doesn't build or design speakers anymore although he does plenty of consultation as he did for the Dutch & Dutch 8C.

Best,
Anand.

dburna

OK......now y'all are FORCING me to make the 3.5-hour drive to Sweetwater soon to demo the JBL 7-Series monitors. It's going to kill an entire day of my vacation to do this, but apparently you folks won't be happy until I do.  :lol:

Seriously, I have the original 305's, and now I think it is time to experience what the next step up will offer. Gonna be interesting. Plus, going to Sweetwater will allow me to head over to the guitar section and drool over some Teles and hollow-body guitars, so it has a side benefit as well. Now I just have to secure my "hall pass" from the Missus.   :roll:

Regards, -dGB

soldermizer

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I am a fan of Danley tech. While I have all too briefly heard some of his Synergy at the Factory, I own the poor man's version, the older tech (Unity) as in the Yorkville Unity U15. While all these products cater to the pro/PA market, there is no reason the smaller ones can't be used in the home. I've read up on these as much as a layman can, and especially the Synergy all boast a passive x-over and all you  ask in the subject for this thread. I encourage you to give a listen to his speakers. DIY versions have been built, but not an easy task. The Yorkville can be had about $1200 per speaker, so certainly competes with many hi-fi brands. A SH-50 will run you about $4000 each, a bit pricier :)

Jonathon Janusz

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P.S. I don't wish to discuss this point here as it will derail the thread, but maybe we can discuss it elsewhere or in private.  I don't get this point at all.  The circle of confusion is term for the intellectual confounding of two vastly different things and only enlightens what the fundamentals should be for good speaker measurements regards of which speaker it is.   The M2 isn't unique in trying to acheive this goal at all.

No need to dwell too much on this, Josh, and I really wasn't trying to poke the bear with a broader music reproduction industry philosophical debate. 

With this statement, I was simply, for sake of keeping the discussion on the speakers out there today that meet the original criteria, trying to head off any immediate and dismissive derailments stating that looking for such a thing (as an offshoot of the JBL speakers conversation) is, "useless," because one (the speakers) without the other (the active/DSP processing) is both a complete contradiction to and the antithesis of the fundamental design concept of the (JBL) speaker system that inspired the thread in the first place. 

Unfortunately, I was unsuccessful in this as (with all due respect) that was literally the first thing Anand posted immediately below you!  :lol: :banghead:  Anand, I get where you're coming from, and nothing but love, but my hope here was to try to see what (else?) is out there right now in terms of getting as close to putting a round peg ("modern" speaker design) into a square hole ("traditional" audiophile stereo rigs) as can be had with speakers currently on the market. 

[Deleted before posting: a slight tangent that TL:DR said that I wouldn't consider trying to engineer a speaker myself]


All that aside, so far I've read about Revel (also from Harman group) and Danley.  For years I've read folks online praise Danley designs, and please do offer up details for folks to get up to speed on what's currently going on in the Danley shop.  If I were shopping for myself right now instead of just OP-ing a general discussion on the subject, my little space would unfortunately have me looking at things a wee bit smaller than Danley's designs.

Thanks everyone and keep the ideas coming!  Although it is starting to sound like the general answer is that there is very little out there that hits all the mentioned check boxes, at least this conversation can serve as an easy to find reference for anyone looking for such unicorns.  :thumb:

poseidonsvoice

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No need to dwell too much on this, Josh, and I really wasn't trying to poke the bear with a broader music reproduction industry philosophical debate. 

With this statement, I was simply, for sake of keeping the discussion on the speakers out there today that meet the original criteria, trying to head off any immediate and dismissive derailments stating that looking for such a thing (as an offshoot of the JBL speakers conversation) is, "useless," because one (the speakers) without the other (the active/DSP processing) is both a complete contradiction to and the antithesis of the fundamental design concept of the (JBL) speaker system that inspired the thread in the first place. 

Unfortunately, I was unsuccessful in this as (with all due respect) that was literally the first thing Anand posted immediately below you!  :lol: :banghead:  Anand, I get where you're coming from, and nothing but love, but my hope here was to try to see what (else?) is out there right now in terms of getting as close to putting a round peg ("modern" speaker design) into a square hole ("traditional" audiophile stereo rigs) as can be had with speakers currently on the market. 

[Deleted before posting: a slight tangent that TL:DR said that I wouldn't consider trying to engineer a speaker myself]


All that aside, so far I've read about Revel (also from Harman group) and Danley.  For years I've read folks online praise Danley designs, and please do offer up details for folks to get up to speed on what's currently going on in the Danley shop.  If I were shopping for myself right now instead of just OP-ing a general discussion on the subject, my little space would unfortunately have me looking at things a wee bit smaller than Danley's designs.

Thanks everyone and keep the ideas coming!  Although it is starting to sound like the general answer is that there is very little out there that hits all the mentioned check boxes, at least this conversation can serve as an easy to find reference for anyone looking for such unicorns.  :thumb:

Jonathan,

Sorry for being obtuse.

But the point is, I too have been on this search and the biggest problem I see is trusting, and/or entrusting if you will said designer to be competent enough to achieve these aforementioned goals of constant and controlled directivity. It isn't easy or perhaps impossible for a one man show, unless they are unusually intelligent, i.e. Geddes, Danley, etc... Even then, Geddes didn't have the resources or cash flow of JBL and as such there were some areas he could not improve upon, especially since he didn't custom design the drivers in his Abbey, NA12 or NS15. They are all from B&C, and although extremely good, they do have minor flaws. With JBL, that isn't so.

That being said there are a few passive CD designs, some waveguide based others coincident based and of course Don Keele's work.

The waveguide based ones you already are aware of, the defunct Geddes line of speakers, and other passive examples from the DIY Sound Group (none of which I have heard). Danley's designs I have listened to once, and it was exceptional, the directivity is even more controlled and narrow. As such, the imaging specificity is absolutely gobsmacking. The problem is in the area of envelopment, where it can sound a bit dry. Still there are ways to overcome that acoustically with judicious use of diffusers in the room, particularly behind the listener. An offshoot of this, is Paul Spencer's/Red Spade Audio PSE-144 (http://redspade-audio.blogspot.com/2014/04/pse-144-launch-update.html), which is available in either passive or active versions. The measurements he has sent me look promising.

JBL's  Studio 580 and 590 shouldn't go without mention, as they come from the same company that developed the spinorama method of measurements and are fine examples of Greg Timbers' work when he was at JBL. They would be on my short list if my daughter got sick of her ELAC B6's she enjoys now. And yes, the Studio 580 and 590 are both passive designs, using very nice, tricked out waveguides.

There are few other examples in the JBL line, including the 4367, etc...

Let us not forget Duke LeJeune of course. He was under the tutelage of Geddes and I am quite sure he remains fastidious in his goals of developing constant and controlled directivity designs now and into the future...

Other passive designs that are non waveguide based include Andrew Jones' ELAC Adantes and KEF's Reference series. I haven't listened to the Adantes yet, but the KEF Reference, I have. They are excellent as well, with wider dispersion (ie, not controlled), but still the dispersion is constant which allows for good imaging and nice broad soundstaging. The biggest issue I have had with KEF is inefficiency. They need at least 100 watts into 4 ohms and room treatment will have to be a bit different, particularly at the 1st reflection points, a hybrid diffuser/absorber will do well there.  The KEF Reference 5 and Blades I have listened to and they are truly excellent sounding and measuring designs.

I have listened to other coincident designs that are higher efficiency such as Spatial M3's and M4's but I wasn't enamored by them at all. Although they did exhibit controlled directivity (+/- 45 degrees), the directivity wasn't constant. This is easily seen in Geddes' Polar plots since he measured the Spatial M4. You will need to download the Polar Map program to view the results, but it was eye opening for me nonetheless. For me, it wasn't worth the coin, given that Clayton's better achievements, ie. the X1 uses a dedicated waveguide from 18Sound I believe, and the X2 likely uses a Beyma AMT. 

And then there are the designs by Don Keele, marketed by Parts Express. They are constant beamwidth transducers and are mentioned in Floyd's book as being the only type of line array that can achieve constant directivity. Loads of research and AES papers are around which are a great read. I had listened to a pair, years back, they didn't sound bad, but I didn't miss them either. I iistened to them again at an RMAF show and once again, said to myself, "meh." I will say that the Parts Express versions are very affordably priced. They are the models CBT24 and CBT36, the number standing for the number of transducers used. If I had a ballroom, maybe...

I am sure the list is  bigger than this...

Best,
Anand.

Folsom

Anand, what about horn speakers? They seem to be discussed less around here probably since they tend to be very expensive.

Jonathon Janusz

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Anand,

It's all good, sir.  I know we've chatted on and off about just this topic, and I had a feeling we were both of similar mind looking about for the same kind of unicorn.  No apologies needed, particularly with such a grand follow up!  I think if nothing else, this discussion will be worthwhile if it gathers together as broad a list as can be figured among the collective so that others shopping for such a speaker can have a short list to audition/work through in their search.

I never got to hear any of the DIY sound group designs, although I've heard from others that Mike G's build was something special (I think it was built off the 18" waveguide and JBL woofers, I don't remember the tweeter and can't remember if it was passive or active).  Between the studio 580 and 590, I've read that folks seem to think the bass is better on the 580, as the 590 gets a little thick/overblown with the bigger woofers, but I haven't heard them myself.  Good news there is that JBL seems to frequently have these around for firesale (around half off) prices.

I did take a long look at the latest speaker from Duke.  I think it is using a modified SEOS waveguide, and I'm unsure if Duke has published which woofer and tweeter was used.  Interesting there that it can be had with or without the James Romeyn LCS effects speaker.

Coaxials have interested me for a while, and I liked the KEF Blade II when I heard it a few times at shows.  I haven't been around lately enough to hear the newer Elac/Andrew Jones stuff.

I wonder how much one could put speakers like the open baffle Spatials in this category.  Granted, the front wave seems to be paid attention to the directivity and pattern control concepts the designs under discussion have as points of distinction, but with the open baffle back wave more or less being uncontrolled, making the polars presumably end up funky no matter what is designed in to the front wave launch (personal preferences aside here for sake of discussion, simply looking at the speaker designs themselves)?  Out of the lot from Spatial, maybe the X1 comes closest, as it only gives up control of the back wave in the bass, as the horn loaded compression driver (in that model, I think?) is closed-backed.

Good stuff!

Jon

JoshK

Some but a very small segment of the horn speakers would fit the criteria of uniform off-axis response, but they do have controlled (just not constant) directivity.

I did a back to back single blind shoot out with one of the DIYSG 15" speaker (iirc the Fusion 15) and at the time my Danley SM60F .   Both are great speakers, but you could hear differences.   Our shoot out was mono and not all the speakers were in exactly the same spot so I did notice some minor changes in character when at the midway point through the test the speakers were shuffled around in location.   Its damn hard to do a real blind test.   I've not seen the off-axis Fusion measurements, or at least I don't recall them but I was told they were good. 

I lived with the Danley's for a few years and really enjoyed them, but they don't make the best standard audiophile speaker because the directivity is a bit too narrow.  I will echo what Anand said, they image like the dickens but they don't have a very wide soundstage and are a bit dry.  They could also use a tiny bit of EQ imo depending on how you place them in a room.   Ultimately my M2s was a clear step up even though the Danleys were pretty fantastic already.  The top end is just a bit cleaner/clearer in the M2, the extention is a bit further up top and also the midbass is much better.   The SM60F's midbass gets a bit boomy if you let it run all the way down to 50hz or so where it drops off, but was great if you HP them at 60 or above and let subs take over.   

I think the market is coming around a bit more to controlled directivity (I'm going to write ConDir from now on for short, since CD means compression drivers to many) speakers, particularly driven by the HT crowd, as it makes a bit more sense there especially since you are using multiple speaker sources and you want to control a lot of excess unwanted (first) reflections.  In pure stereo, again I don't think there is absolute consensus on ConDir versus wide but uniform directivity.  Some prefer the prior (me, jtwrace, Anand likely) while many I know like the Revel type sound with the wider dispersion.   I will say that ConDir allows you to get away with a poorer room than the latter. 


poseidonsvoice

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Anand, what about horn speakers? They seem to be discussed less around here probably since they tend to be very expensive.

Yes horns can be an example, some are expensive and some are inexpensive, however, that in and of itself isn’t a criteria for competency.

Pi Speakers by Wayne Parnham are designs that do exhibit constant and controlled directivity  but using more of a horn than a waveguide:

http://www.pispeakers.com/Pi_Speakers_Info.pdf

He has other examples on his website including corner horns, and has a loyal following as well.

Recently I was pm’d by an AC’er who wanted me to look at measurements of a Klipsch design from their pro division. It looked promising as well. Here it is: https://f072605def1c9a5ef179-a0bc3fbf1884fc0965506ae2b946e1cd.ssl.cf2.rackcdn.com/product-specsheets/KI-396-SMA-II-Data-Sheet-v05.pdf

That being said, just like waveguides, there are examples that would not pass my scrutiny!

https://www.stereophile.com/content/volti-audio-rival-loudspeaker-measurements

Best,
Anand.

Folsom

What do you think about Cessaro type horns?

poseidonsvoice

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What do you think about Cessaro type horns?

They look beautiful, and that’s about all I can say.

Best,
Anand.

Folsom

I haven't been to a show with anything but Volti's (already covered), and some Classic Audio ones (horrid). Never heard WE's or anything like that. They have directivity.


JoshK

As Anand mentioned, the 3pi and 4pi speakers from Wayne look to fit the bill and are completely passive.   I am not sure if you can buy they turn-key or whether  you have to assemble yourself.   Wayne has always taken the measurements serious in designing and also did a number of videos show the average diy'er how to do it.

dburna

Recently I was pm’d by an AC’er who wanted me to look at measurements of a Klipsch design from their pro division. It looked promising as well. Here it is: https://f072605def1c9a5ef179-a0bc3fbf1884fc0965506ae2b946e1cd.ssl.cf2.rackcdn.com/product-specsheets/KI-396-SMA-II-Data-Sheet-v05.pdf

RE:  Klipsch KI-396-SMA-II . Wow - 101dB sensitivity with peaks of 133dB. This is a real "play to your neighborhood" type of speaker.

And 60-18kHz +- 3dB. Looks like they are not fudging the frequency response either.

I wonder if this could be used as a foghorn in the maritime regions.   :lol:

-dGB

Tomy2Tone

RE:  Klipsch KI-396-SMA-II . Wow - 101dB sensitivity with peaks of 133dB. This is a real "play to your neighborhood" type of speaker.

And 60-18kHz +- 3dB. Looks like they are not fudging the frequency response either.

I wonder if this could be used as a foghorn in the maritime regions.   :lol:

-dGB

Klipsch ain’t fooling when they say “Pissing off the neighbors since 1946”

I was the one who messaged Anand about the 396’s and just received them yesterday. I was all set to get a pair of Forte III’s when I kept reading about how a lot of Klipsch owners have moved on to their Pro series speakers and the 396 ranked highly so I took a chance on a good deal on some b-stock. It’ll be a week or so before I get them setup in my listening space and get a feel for what they do.  They’re my first constant directivity speaker.