Scaling LCS effects speakers

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matt.w

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Scaling LCS effects speakers
« on: 1 May 2014, 08:22 pm »
Don't want to derail the Z Speakers thread, so creating a new one:

The original Dream Maker LCS effects speakers, or perhaps a scaled-back version, could be added to your Planetarium Alphas, so you could sort of have your cake and eat it too. 

From James Romeyn's page for the Dream Maker LCS Effects Speaker (http://jamesromeyn.com/#/home-audio-gear/dream-maker-lcs-late-ceiling-splash-loudspeaker-system):

Quote
Dimensions in preferred setup: HWD 10 x 20 x 28

I'm curious, just off the cuff, how small could the effects speakers be scaled to? What would be lost in the process? (I'm assuming bass extension, for starters)

Duke

Re: Scaling LCS effects speakers
« Reply #1 on: 2 May 2014, 06:12 am »
I'm curious, just off the cuff, how small could the effects speakers be scaled to? What would be lost in the process? (I'm assuming bass extension, for starters)

Efficiency was also a factor in the box size of the original effects speaker.  But if you drive the effects speaker with its own separate integrated amp, you can adjust its volume as needed.

The large size does help us to maintain pattern control down lower in frequency than we could with a smaller size, but there's plenty of leeway before it gets "too small".   I wouldn't want to go down to a single dome tweeter, for example, because I think its pattern would be too wide, but we could probably get away with a small waveguide or horn in a box roughly 14" x 9" footprint by 8" tall. 

fakamada

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Re: Scaling LCS effects speakers
« Reply #2 on: 17 Jun 2014, 11:34 am »
Duke, is LCS radiating with same SPL as front speakers? Or perhaps it is  a bit quieter?

Duke

Re: Scaling LCS effects speakers
« Reply #3 on: 17 Jun 2014, 09:07 pm »
Duke, is LCS radiating with same SPL as front speakers? Or perhaps it is  a bit quieter?

Since the LCS array is a player in the reverberant field only, its radiation pattern width is as almost as much a factor in how loud it is as its on-axis SPL.   And its native frequency response curve takes its proximity to room boundaries into account.   But to answer your question as simply as possible, yes the LCS array is slightly lower in level than the main speaker.

steve f

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Re: Scaling LCS effects speakers
« Reply #4 on: 22 Jun 2014, 05:33 am »
Duke/Jim, 

A buddy asked me a question. "If a speaker can benefit from a delayed ceiling splash, can a speaker also benefit from a delayed floor splash." He assumes that the flooring material is non absorbing tile or wood.  My answer was hmmm... I don't know, but I'll ask somebody. The concept might be viable where speaker size or placement may be an issue. Also furniture might get in the way. Guys?   :scratch:

BTW I've tried splash speakers before and  have listened to designs by Lowther, Allison, Linkwitz, and a few others who used up firing drivers, but none who tried to physically maximize the delay. This is intriguing stuff.

Steve

Duke

Re: Scaling LCS effects speakers
« Reply #5 on: 22 Jun 2014, 08:19 am »
Duke/Jim, 

A buddy asked me a question. "If a speaker can benefit from a delayed ceiling splash, can a speaker also benefit from a delayed floor splash." He assumes that the flooring material is non absorbing tile or wood.  My answer was hmmm... I don't know, but I'll ask somebody. The concept might be viable where speaker size or placement may be an issue. Also furniture might get in the way. Guys?   :scratch:

BTW I've tried splash speakers before and  have listened to designs by Lowther, Allison, Linkwitz, and a few others who used up firing drivers, but none who tried to physically maximize the delay. This is intriguing stuff.

Steve

I presume you mean firing a ceiling-mounted speaker down at the floor?

The direct side-lobe angle to the normal seated listening location is a bit less acute, so we'd need a bit more aggressive pattern control, and wouldn't have the benefit of the main speaker's cabinet possibly acting as a "shadow" to block that early side-lobe energy from the listening area. 

Assuming we cleared that hurdle, I'm really not sure how it would work perceptually.  I don't know for sure how much the ear/brain system cares about the vertical angle that this extra reverberant energy comes in from, but I think Jim's configuration has it happening in the most desirable area (generally above the speakers; there's an argument for bringing it in to the outside of the speakers, but in practice that didn't work as well, maybe because of the reduced delay times).  Unfortunately I can't say for sure what that implies, or does not imply, for a floor-splash system. 

So I guess my answer is, a good floor-splash system would be a bit more of a challenge to get right, and I'm not sure what the results would be... probably a net benefit, but I would be surprised if it's as much of a net benefit.

cloudbaseracer

Re: Scaling LCS effects speakers
« Reply #6 on: 26 Aug 2014, 09:02 am »
Duke,

Does the ceiling that the LCS speakers bounce off of need to be parallel with the floor?  In other words, would these still work with a left to right upward sloping ceiling? 

Are the timing delays simply a function of relative placement or is it done with some electronic delay?

Cheers,
James

James Romeyn

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Re: Scaling LCS effects speakers
« Reply #7 on: 26 Aug 2014, 10:04 pm »
Duke,

Does the ceiling that the LCS speakers bounce off of need to be parallel with the floor?  In other words, would these still work with a left to right upward sloping ceiling? 

Are the timing delays simply a function of relative placement or is it done with some electronic delay?

Cheers,
James

Duke and I tested the full system in a local auditorium with 16' ceiling.  Turning the LCS on/off all three persons present including my wife with better hearing them me, agreed LCS performance advantage seemed similar in 8' and 16' ceiling.  I wrongly suspected performance loss with such tall ceiling, resulting from less LCS magnitude of effect resulting from the primary reflective boundary (the ceiling) being farther from the listener.  IIRC, Duke explained the increased ceiling distance does not minimize LCS magnitude, it simply increases delay and spreads reflection over a larger surface area.  If I understand correctly then, the net sum total of the Main Speaker (on-axis) and LCS effect is much less dependent on the ceiling than we might suspect. 

We'll see what Dr. Duke says about this. 

Delay derives from only LCS architecture, siting, and the boundaries.  There is absolutely no electronic delay.

After repeating it in my head enough times (it IS hard to teach old dogs new tricks), I can clearly list LCS goals, which parameters were all defined by some of the world's most brilliant loudspeaker designers Dr. Floyd Toole and Dr. Earl Geddes.  Ideal reverberant field qualities/parameters:
  • Full range
  • High in magnitude relative to on-axis signal
  • Maximum random, decorrelated signal relative to on-axis signal
  • Delayed 10ms-20ms relative to on-axis signal (11.3' to 22.6'...this spec is "fuzzy" rather than concrete)
The sum total effect of LCS achieves the above goals to greater degree than any other known production loudspeaker.  The sum total extent to which any other speaker addresses #3 is zero.  Even if some other method more efficiently addressed #3, it would require greater complexity and increase cost for unknown potential benefit.

This also relates to the ceiling being uneven L to R: I suspect it's very possible this could increase random/decorrelated effect, which could further improve performance.  The greater is reverberant field decorrelated from on-axis signal, the better is performance.  It's possible that the less symmetrical is the ceiling L/R the better is performance.     

Ideal reverberant field improves more than just image and spatial qualities.  The better is the listener's pitch acuity, the more they will notice improved pitch center of notes.  Listeners can and will notice greater interest in music with greater complexity. 

Also, ideal reverberant field improves musical detail without resorting to any "tricks" such as exotic cone materials, costly cabinet materials, etc, etc.  I have nothing against such practice, but after living with LCS and turning it on/off as many times as I have, I'm convinced the way it improves musical detail without any highlighting or etching is highly addictive, always pleasing, and never tiring on the ears. 

There is reason to believe LCS can improve the performance of any speaker regardless its radiation pattern, even a planar dipole.  Beyond what appears to be the premier reverberant field performance, LCS offers the following improvements for persons considering adding it to a pre-existing main speaker.  One of the following advantages is definite, the other likely.

Deeper bass cutoff for Main Speakers that cutoff above the "low 30s."  The floor is ideal for placement of the LCS speaker firing upward, especially behind the Main Speaker, which "shadows" the LCS' off-axis radiation to listeners throughout the room.  Beyond that, the floor and nearby vertical boundaries are "free lunch" for increasing deep bass output.  With floor and vertical boundary reinforcement we project bass cutoff in the "low 30s."  This is especially nice for stand mount Main Speakers.  Many audiophiles enjoy stand mounts over floor standers because they hate bass mode effects which are more prevalent with larger floor standing speakers, which segues nicely into the next item...

Free Bass Mode Damping in 3-D space and throughout the room, not electronic EQ which worsens performance at points other than the mic test location.  The sum total of two Main Speakers and two LCS = four bass sources in the room, each occupying a different geographic space, exactly ideal per another PhD. named Pierre Sprey of Mapleshade, and others who promote Distributed Bass Array. 

Users get to invert the polarity of either (not both) of the LCS full range speakers.  Wow, you think, that will just totally destroy everything associated with spatial effects.  And you'd be totally wrong.  In fact, consistent with everything else advertised, in the mid/treble and spatial wise, you can not tell whether one channel is inverted or not.  How's that for strange? 

Why?  Relative to on-axis signal most of LCS energy is delayed 10ms or longer.  Inverting it's polarity is inaudible in the mid/treble range and has no effect on spatial quality because 180-degrees is such a tiny fraction of one percent of its delay time vs. on-axis signal.   

But in the bass range it is audible, and only in a good way.  It damps bass mode effects.  Depending on the modes, on some program it's just audible, on others it's quite huge.  Inverting one side normally works better than the other.  Try both channels.  You'll like the effect so much on the first channel you might be lazy and not try the other channel, which could work better.  (Senator, I can not deny nor agree I am guilty of the charge.) 

So beyond making your image and spatial dreams come true, you get a sub woofer and a good portion of the advantage of a Distributed Sub Array.

Lawn mower and breakfast in bed features coming.     
   

borism

Re: Scaling LCS effects speakers
« Reply #8 on: 26 Sep 2014, 05:05 pm »
Duke,

Any success in scaling down the LCS effects speaker and hopefully making it compatible with your older designs?

Thanks,
Boris

Duke

Re: Scaling LCS effects speakers
« Reply #9 on: 26 Sep 2014, 10:30 pm »
Duke,

Any success in scaling down the LCS effects speaker and hopefully making it compatible with your older designs?

Thanks,
Boris

That will definitely happen, and it will be compatible, but on the first set of enclosures from my woodworker I made a mistake and didn't allow enough space for grilles.  So he;s buiding the second set now, 

I expect to pick up the enclosures next week and have the production version ready to show at RMAF in a couple of weeks. 

borism

Re: Scaling LCS effects speakers
« Reply #10 on: 27 Sep 2014, 09:36 pm »
Thanks, Great news!

Duke

Re: Scaling LCS effects speakers
« Reply #11 on: 23 Dec 2014, 08:36 am »
The dedicated LCS speaker will use four 5" woofers arrayed around a single rectangular waveguide, two above and two below, to give good radiation pattern control down as low as is possible within the footprint of the system.   I'm going for more aggressive pattern control than what you've seen in my front-firing speakers, as in my experience pattern control is especially important for this application.   

The dedicated LCS speaker will benefit the bass and lower midrange of typical stand-mount monitors in four ways:

1) It will extend the low end a bit deeper (largely because of boundary reinforcement);

2) it will smooth out the low end response because it will be a second low-frequency source that is at a different distance from room boundaries;

3) it will tend to offset the effects of the baffle-step; and

4) it will tend to fill in the floor-bounce notch.

All this plus improved timbre, soundstage depth. and feeling of immersion in the acoustic space of the recording.   

JLM

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Re: Scaling LCS effects speakers
« Reply #12 on: 23 Jan 2015, 11:33 am »
Do keep us posted Duke!

Duke

Re: Scaling LCS effects speakers
« Reply #13 on: 25 Jan 2015, 08:51 am »
Do keep us posted Duke!

Here's a sneak preview:



The unusual dense-pack configuration is all about good radiation pattern control down to as low as is feasible given the 12" x 17" footprint. 

The grille will "float" on the four rectangular blocks you see near the corners.

Larkston Zinaspic

Re: Scaling LCS effects speakers
« Reply #14 on: 25 Jan 2015, 04:53 pm »
Are these backwards compatible with my original Jazz Modules? Do you recommend a separate amp for the LCS speakers?

Thanks.
~Greg

James Romeyn

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Re: Scaling LCS effects speakers
« Reply #15 on: 25 Jan 2015, 06:53 pm »
LCS 2.0 or whatever Duke christens it, available either 4 Ohm or 16 Ohm (same 4 Ohm mid bass wired either series/parallel or series).  The first pair in the image is mine and available for demo shortly, and I ordered 4 Ohm.   

IIRC your lovely original JM are 8 Ohm and till Duke chimes in I'm thinking:
JM 8 Ohm parallel w/LCS 4 Ohm = 2.6 Ohm nominal, too low
JM 8 Ohm parallel w/LCS 16 Ohm = 6 Ohm OK but LCS sensitivity possibly too low 
JM 8 Ohm series w/LCS 4 Ohm = 12 Ohm OK, sensitivity balance unknown
JM 8 Ohm series w/LCS 16 Ohm = 24 Ohm too high

To the rescue is this little charming amp w/level control: http://www.parts-express.com/dayton-audio-dta-120-class-t-digital-mini-amplifier-60-wpc--300-3800  Stone cold out of the box Duke and I A-Bd it vs. my modified Pioneer 912 receiver. The amp is perfectly suited for LCS duty for most speakers, including earlier pre-LCS AudioKinesis: 40/60W @ 8/4 Ohm (estimate 20W @ 16 Ohm, which is why I ordered the LCS demo in 4 Ohm). 

To compare LCS on vs. off, unplug the DC power input on the amp rear panel.  Using the volume control to power down is impossible to insure matched levels.  Too much volume masks detail; perfect volume is a perfect blend of on-axis + reverberant field.  When LCS level is perfect it is net gain in every parameter, with no loss of fine detail, and turning LCS on/off is the last word in proof (LCS off requires +1 to 2dB system gain...for systems employing subs, sub gain must be cut same dB as system gain is increased for proper A-B test).     

So, to get the ball rolling, I shall include the above amp free with LCS purchase, and even include free shipping to CONUS for $2900/pr MSRP. 

Of course, any spare stereo amp with level control (integrated, receiver, etc) can power LCS to match with pre-existing main speaker.  Depending on the amp, order either 4 Ohm or 16 Ohm LCS.  Contact any LCS dealer (Duke, myself, Brian Walsh, or Tony Chipelo) for advice selecting 4 Ohm or 16 Ohm for partnering amp.     

Stay tuned for earth shaking review from Zephrin 46 (includes LCS feature) buyer in MI who has owned more speakers than an audio store. 

If you system lacks spare preamp outputs to drive the LCS amp, I shall make for only $75 (again, to get the ball rolling), a "Bridging Network" designed by Jack Elliano (speaker to line level attenuator), perfect for this application: large gold binding post inputs, superb gold RCA jacks milled from solid alloy/gold plate, or unbalanced Neutrik XLR outputs/gold contact, plain wood box painted flat black HWD 2.5 x 8 x 3" (1W resistors and terminal strip plus rear panel connectors require real estate).  As delivered the BN works only in parallel with a speaker load (your main speakers), meaning it does not work as a stand alone attenuator.

For the time being I'll also make and drop ship BNs as above for other LCS dealers.   
     
 
« Last Edit: 25 Jan 2015, 08:06 pm by James Romeyn »

bradmorris1

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Re: Scaling LCS effects speakers
« Reply #16 on: 25 Jan 2015, 09:31 pm »
James,  you say you ab'd the little t amp against the modified pioneer 912 but you didn't say how it compared.  I'm curious because I own (and am very happy with) the very same modded 912.
Brad

James Romeyn

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Re: Scaling LCS effects speakers
« Reply #17 on: 25 Jan 2015, 10:05 pm »
James,  you say you ab'd the little t amp against the modified pioneer 912 but you didn't say how it compared.  I'm curious because I own (and am very happy with) the very same modded 912.
Brad

Well, first, the Pioneer has thousands of hours, powered up continuously, and with every mod I could imagine since it became primary component late 07-early 08.  (Since 2011 I use three 912s: one is preamp in the rack off-center, one next to each main speaker as 2-ch power amp...contact me for an external wiring option you might have missed for huge upgrade driving speakers, but little to no gain as preamp.)

We went back and forth several times, IIRC testing only one channel, the Right LCS.  And again, the first time the Dayton amp ever saw current was one or two minutes prior.     

Duke and I agreed the 912 was "a little warmer" and for most or all users the Dayton would pass minimum performance level for LCS application.  I'll add the 912 seemed a little more sweet, musical, and laid back, but only moderately so.  The Dayton might have been more dynamic, but I'd be surprised if it outperformed the 912 in any area.  We agreed the Dayton has wide range of gain adjustment, also valuable for this application.  Users employ the Dayton as primary amp in first and second systems.  A majority report it is a great component worth multiples its price, and not a toy as you'd be forgiven for thinking.     

I forgot to mention earlier, I have for sale at special price the following 8 Ohm LCS pair, which perfectly matches original Jazz Module with only one amp: JM 8 Ohm + this LCS 8 Ohm = 4 Ohm parallel or 16 Ohm series:
  • 8 Ohm
  • HWD 13 x 17 x 20
  • Real walnut veneer, black grilles
  • Same waveguide as image above
  • Four 5.25", same symmetrical rectangular array per Duke's image above
Above is the LCS on which we performed the A-B test.  You can see dimensions are much closer to the current LCS in Duke's image vs. the original LCS at 2013 RMAF which was huge, about 11 x 20 x 30. 

Sorry, camera brokey and no images till I repair it.