Speaker Recommendations for the RM-10 MK II 25 watt version ....

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James Romeyn

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Well engineered electrostatic panel exceeds the best cone in speed, providing great detail and transparency.  The longer one has enjoyed the audiophile pursuit, the more likely they know that a wide array of performance attributes contribute to overall sense of joy and pleasure.  And each individual weighs those performance attributes differently.  We all know what we like and how much we like it when we hear it.       

Late Ceiling Splash (LCS) provides a unique radiation pattern meeting all of Dr. Floyd Toole's and Dr. Earl Geddes' four specifications for ideal reverberant field.  At least one unnamed specification exceeds any other architecture including electrostatic panel.

Jason Victor Serinus of Stereophile noted HERE:

Quote
...The way the speakers' LCS Late Ceiling Splash radiation pattern, which was invented by James Romeyn and Duke LeJeune (implementing reverberant field theories by Dr. Floyd Toole and Dr. Earl Geddes), threw images way high, as well as their amazing three-dimensionality, was quite impressive...

Toole specifies an ideal reverberant field provides the ear-brain a so-called "second look" at the original waveform, increasing the listener's sensitivity to pitch and detail information.  For instance: the on-axis signal portrays an F# fundamental tone.  A "second look" in the reverberant field confirms and cements the initial on-axis perception.  This happens in real time, and rather than distract the listener, it decreases stress and allows the listener to more fully relax into the illusion of live sound.

After working with LCS for a few years now, I feel safe in reporting that it increases detail and pitch sensitivity.  In fact, I believe it increases pitch sensitivity so well that one interesting result is the listener's ability to appreciate more complex musical scores, and increased interest in music which previously the did not interest the listener. 

I'm under the impression that cone/dome speaker builders constantly struggle with yin-yang regarding detail vs. musicality or smooth musical presentation.  There's a certain preferred middle point on this imaginary scale.  Too much detail decreases musical enjoyment and causes fatigue.  Too much musical smoothness masks detail. 

LCS generates detail and transparency in a unique and efficient fashion that decreases fatigue and increases listening satisfaction and musicality.  LCS does not rely on the usual detail vs. musicality scale described earlier. 

Reflected energy arriving prior to about 10ms does not help in the way described above because the ear-brain can not properly separate and process it compared to the initial on-axis signal.  Speed of sound 1130fps x .01s (10ms) = 11.3ft.  Dipole and bipole lovers often prefer about 5.5ft front wall spacing because 5.5' approaches a 10ms delayed reverberant field (speaker to wall back to speaker).       

Dipole, Bipole, and omni-pole rely on front wall reflection for reverberant field effects, while LCS does not.  LCS can setup flush with the front wall and still maintain most of its spatial excellence including the "second look" mentioned above (stage depth increases with some front wall spacing).

LCS also provides electro-mechanical bass mode damping feature throughout most of the listening room, not like EQ which worsens performance outside the mic test locations. 

One last item, and my apology for being so long winded.  With all the legendary accolades heaped on Peter Walker's Quad 57, home theater use is not one of them.  After spending significant time assembling the highest value and best performing 2-ch music system, why must one suffer inferior audio performance in the HT system?  Especially going from one of Roger's tube amps to a digital amp receiver!  Yech!

Down to its high 30 Hz cutoff, two Zephrin 46 provide a superb L/R Front Array for HT, including uncompressed peaks with low powered tube amp.   

The great tube fanatic Lynn Olson says dedicated HT speakers generally have extremely "dry" acoustic in the front LCR array, providing ambiance and reverberant field effects only in the surrounds.  Lynn says this is the opposite of nature, causing quick fatigue and desire to do something else. 

Conversely, Zephrin 46s LCS provide dense and immersive spatial effects in the L/R Front Array.  Lastly, its center image quality from only two L/R speakers challenges the most costly L/C/R array. 

And no dreaded step down in performance when moving from 2-ch to HT.  Build two to four mono pole speakers (no other radiation pattern) into the walls and you're done...(well, maybe a sub too).                 

Clio09

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Hi Roger,

Thanks for mentioning the Pioneer speakers. I had an opportunity to sit with Andrew Jones for an extended period of time at CES along with several folks and he was gushing over his new Pioneer designs. Your comment on the stacked pairs really has me intrigued and I will be trying this out in the near future.

I would also like to note that it was my room at Newport where we had the Zephrin 46 speakers paired with Our 300b amps and a set of Atma-Sphere m-60s. While being able to run those speakers as a 32 ohm load is certainly an attraction, I will say that both amps performed better with the 8 ohm configuration.

I did look at the speaker. Its nice that it is available in 32 ohms, so thanks for that. Personally, I'm not inclined to compare cones to ESLs.

I have heard some speakers that rival ESLs in midrange clarity (the inexpensive Pioneer SP-bs22 is excellent at $130 a pair). It was a bit of an inspiration for the OTL-1. In visiting a friend who had stacked them 4 high I got to thinking, here is a 32 ohm load if connected in series. One pair is fine for nearfield use, but a stack of 4 made a nice linesource, more bass, though I think a sub is still warranted. A line source is my preferred type of speaker as solves many acoustic problems like floor bounce, vertical directionality and I think makes the most sensible choice in how to, as Beveridge said, "illuminate a room". Overall this attractive stack was the best $500 speaker I have ever heard.  There are several reviews of this speaker, Stereophile being one of them. http://www.stereophile.com/content/pioneer-sp-bs22-lr-loudspeaker

The OTL-1 would be very happy driving this load to very high levels. Stacking them higher is fine too. At 86 dB sensitivity they are a bit low but a stack of 4 will raise the efficiency 6 dB to 92 and there will be far less drop-off with distance. We know a line source drops off more gradually than a point source. I believe the numbers are 6 dB vs 3 dB when you double the distance. So if you listen several meters from your speaker that will be an important factor in choosing the line source.

As the speaker impedance is increased we get more amplifier power also. In total the system power will rise 6 dB every time we double the number of speakers. That 3 dB from the speaker and 3 dB from the amplifier for each doubling.

tubegroove

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FWIW, if you are interested in regular cone speakers check out Green Mountain Audio bookshelf speakers (EOS or Rio depending on your budget).  These are honest 90dB and benign 4ohm impedance (www.greenmountainaudio.com).  Very real and musical, first order x-over speakers which work well with the RM10MkII (35w version).  Also look for them cheaper on the used market

corndog71

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I can recommend some high quality b-stock speakers.  They just need a little more poly-fill inside the cabinets.

http://www.audiocircle.com/index.php?topic=116702.0

tdinut

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Any opinion on using Devore 0/96 with the RM-10? A friend has a pair for sale. I can't try them, he's in another state.


Description: Two-way, stand-mounted loudspeaker with reflex port. Drive-units: 1" silk-dome tweeter, 10" paper-cone woofer. Frequency range: 25Hz–28kHz. Sensitivity: 96dB/W/m. Impedance: 10 ohms nominal, 8.75 ohms minimum (at 200Hz).

[size=78%][/size]

[/size]http://www.devorefidelity.com/speakers/images/o96.jpg[size=78%][/color]

JackD

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Joe

Those should work great with the RM-10.  Most of the time those are driven with SET's of lower output than the RM-10. I have driven 2CE Sigs with the RM-10 in the past to much higher levels than you usually listen to.  Also as tubegroove said, the Green Mountains work well too.  The RM-10 is in my office now with the Green Mountain Europa.

corndog71

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Oooh!  The Orangutans!  I heard those at Axpona and was very impressed.  They sounded way better than one might think coming from such a generic-looking box enclosure.  Not too crazy-priced either if I remember correctly.  The finish on them was excellent.

bdp24

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I did look at the speaker. Its nice that it is available in 32 ohms, so thanks for that. Personally, I'm not inclined to compare cones to ESLs.

I have heard some speakers that rival ESLs in midrange clarity (the inexpensive Pioneer SP-bs22 is excellent at $130 a pair). It was a bit of an inspiration for the OTL-1. In visiting a friend who had stacked them 4 high I got to thinking, here is a 32 ohm load if connected in series. One pair is fine for nearfield use, but a stack of 4 made a nice linesource, more bass, though I think a sub is still warranted. A line source is my preferred type of speaker as solves many acoustic problems like floor bounce, vertical directionality and I think makes the most sensible choice in how to, as Beveridge said, "illuminate a room". Overall this attractive stack was the best $500 speaker I have ever heard.  There are several reviews of this speaker, Stereophile being one of them. http://www.stereophile.com/content/pioneer-sp-bs22-lr-loudspeaker

The OTL-1 would be very happy driving this load to very high levels. Stacking them higher is fine too. At 86 dB sensitivity they are a bit low but a stack of 4 will raise the efficiency 6 dB to 92 and there will be far less drop-off with distance. We know a line source drops off more gradually than a point source. I believe the numbers are 6 dB vs 3 dB when you double the distance. So if you listen several meters from your speaker that will be an important factor in choosing the line source.

As the speaker impedance is increased we get more amplifier power also. In total the system power will rise 6 dB every time we double the number of speakers. That 3 dB from the speaker and 3 dB from the amplifier for each doubling.

Roger, when the Pioneers are stacked, aren't the acoustic centers of the tweeters far enough apart to cause audible comb-filtering over much of the driver's bandpass? Even slight head movement will result in pretty severe phase-cancellation, I would think.
« Last Edit: 6 Jul 2014, 07:30 am by bdp24 »

Roger A. Modjeski

Roger, when the Pioneers are stacked, aren't the acoustic centers of the tweeters far enough apart to cause audible comb-filtering over much of the driver's bandpass? Even slight head movement will result in pretty severe phase-cancellation, I would think.

Perhaps, but I thought they sounded pretty good. I only listened to the stack briefly. I did buy a pair and listen to them with my sub and was very pleased by the accuracy of the midrange and highs.

I hear a lot about this comb-filtering effect. I design and work with line source Electrostatic Speakers which do not have that problem.  Perhaps you can send a link to a good paper. I am not so sure it is a big deal, but I will comment. The filtering would be up and down and not side to side I believe. I don't move up and down when I listen.

Doublej

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Roger

Where can one find information on your subs?

Roger A. Modjeski

There is a bit here  http://www.audiocircle.com/index.php?topic=45966.0

You can write airhead, he has a pair with his Stax ESLs and loves them.

corndog71

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Roger, when the Pioneers are stacked, aren't the acoustic centers of the tweeters far enough apart to cause audible comb-filtering over much of the driver's bandpass? Even slight head movement will result in pretty severe phase-cancellation, I would think.

According to one speaker designer, you would be better off turning one of the stacked speakers around to face the front wall.

Roger A. Modjeski

According to one speaker designer, you would be better off turning one of the stacked speakers around to face the front wall.

That sounds fine to me. I would choose one not at ear level nor at the bottom.

Here is a good article on comb filtering. Note that often he is talking about multiple drivers horizontally not vertically.  http://www.audioholics.com/loudspeaker-design/comb-filtering

It  might be interesting to rotate the speakers slightly to spread the highs as Sonab did with their tweeters.

bdp24

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According to one speaker designer, you would be better off turning one of the stacked speakers around to face the front wall.

Just the guy I was going to refer Roger to, Corndoggie (I recognize you from our mutual interest, Danny Richie's speaker design work). Danny Richie at GR Research talks about the subject quite a lot. I use panels exclusively (except as subs. I even use the bass panels of Tympani IV's as woofer panels!), so it's not a major concern of mine. Cones have bigger problems than possible comb-filtering!

Flyin_V

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In visiting a friend who had stacked them 4 high I got to thinking, here is a 32 ohm load if connected in series. One pair is fine for nearfield use, but a stack of 4 made a nice linesource, more bass, though I think a sub is still warranted. Overall this attractive stack was the best $500 speaker I have ever heard.  There are several reviews of this speaker, Stereophile being one of them. http://www.stereophile.com/content/pioneer-sp-bs22-lr-loudspeaker.

Roger,

The stacking sounds very interesting. Were all four boxes placed with the woofers on the bottom or were the second and forth pair inverted?

Now if the 22s will go on sale again for $65.  :D

Thanks.

Lary

Roger A. Modjeski

When were they on sale for $65? What a deal. Are they overstocked? I did walk into Good Guys or one like it and was told they had them but no more.

I don't think the stacking position would make much difference, but one could put on long enough wires and play with it.

OzarkTom

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srb said New Egg has them today for $80 shipped.

dburna

Any opinion on using Devore 0/96 with the RM-10? A friend has a pair for sale. I can't try them, he's in another state.


Description: Two-way, stand-mounted loudspeaker with reflex port. Drive-units: 1" silk-dome tweeter, 10" paper-cone woofer. Frequency range: 25Hz–28kHz. Sensitivity: 96dB/W/m. Impedance: 10 ohms nominal, 8.75 ohms minimum (at 200Hz).

[size=78%][/size]

[/size]http://www.devorefidelity.com/speakers/images/o96.jpg[size=78%][/color]

I listened to these at AXPONA 2014 (Chicago) under sub-optimal conditions, and these were one of the (very) few speakers that I liked.  I have been less enthusiastic about some of the other DeVore speakers (thought some of them were a little bland), so take this assessment for what it is worth.  I thought the O/96's had an immediacy that some of the other DeVore's lacked.

Regards, -dB

Roger A. Modjeski

I listened to these at AXPONA 2014 (Chicago) under sub-optimal conditions, and these were one of the (very) few speakers that I liked.  I have been less enthusiastic about some of the other DeVore speakers (thought some of them were a little bland), so take this assessment for what it is worth.  I thought the O/96's had an immediacy that some of the other DeVore's lacked.

Regards, -dB

With that sensitivity and highish impedance its a nice speaker for the RM-10 or the new OTL-1.