AudioCircle

Community => Regional Audiophiles => Gateway Audio Society => Topic started by: dcbingaman on 12 Oct 2019, 09:41 am

Title: Magnepan LRS
Post by: dcbingaman on 12 Oct 2019, 09:41 am
Just got a pair of these from Magnepan.  Pretty freaking awesome.  Youse guys need to come over sometime to hear these things.  Its like a 21st Century Quad ESL-57.....its really that good in the midrange.  A couple caveats - they need a lot of current to drive them.  My Aleph 5 works, but just barely.  The second is they run out of poop at about 50 hz.  I tied them to an Outlaw subwoofer and they work pretty well, however.  Definitely a speaker that needs some augmentation, LOL.

Let me know when you major dudes and dudettes would like to come hear these things.  I can haul them over to Dave S.'s place if that works - they are relatively light weight.

(https://www.audiocircle.com/image.php?id=199580)




Title: Re: Magnepan LRS
Post by: popthinker on 12 Oct 2019, 11:18 pm
Sounds very intriguing. Count me in...wherever the audition is!
Title: Re: Magnepan LRS
Post by: wedweb on 14 Oct 2019, 12:54 am
I've never heard any panels live before.  So, I'd be up for a meet.

Bo
Title: Re: Magnepan LRS
Post by: pinkfloyd4ever on 18 Oct 2019, 03:26 pm
Oooo heck yes I too have never heard Maggie (or any other ribbon/panel/electrostatic speakers). I was watching a Steve Guttenberg video about the LRS and I'm definitely interested in hearing them. :thumb:

I wish I could offer to host but our house is tiny and my listening space is not too good  :|
Title: Re: Magnepan LRS
Post by: SteveFord on 18 Oct 2019, 09:29 pm
Never heard planars?
Hold onto your wallet, they're kind of addictive.
Title: Re: Magnepan LRS
Post by: thunderbrick on 19 Oct 2019, 03:56 am
If GASsers want to hear large panels, I'm up for a small gathering down I-44.
Bob
Title: Re: Magnepan LRS
Post by: SteveFord on 19 Oct 2019, 09:22 am
Stay away from Thunderbrick's place, once you hear what he's got you're doomed.
Title: Re: Magnepan LRS
Post by: Saturn94 on 19 Oct 2019, 01:17 pm
Never heard planars?
Hold onto your wallet, they're kind of addictive.

At least with the LRS the hit isn’t too bad. ;)
Title: Re: Magnepan LRS
Post by: Blackmore on 19 Oct 2019, 03:57 pm
Hey Don,
Any ideas on a listening session for the LRS?  Sundays aren't good for me but I've got a lot of Saturdays off and would love to hear your pair

Mark
Title: Re: Magnepan LRS
Post by: mjmsound on 9 Nov 2019, 01:34 pm
"Stay away from Thunderbrick's place, once you hear what he's got you're doomed."

Heard Thunderbrick's setup. Sounds great, should not miss it.
Title: Re: Magnepan LRS
Post by: dcbingaman on 9 Nov 2019, 11:13 pm
Hi, guys, I am actually waiting to do a two-fer for you guys.  The SECOND speaker pair may be more impressive than the Maggie LRS speakers.  I am in the process of finishing up a pair of Pass / Linkwitz SLOB's - that is Slot-Loaded bass augmented Open Baffles.  This speaker design combines a full-range 8" Cube Audio driver set in a 20"W x 40"T open baffle and a 15" Eminence super woofer which propagates through a 3"T x 16"W slot just below the baffle board.  This is Pass's reference speaker and only about 2 pairs exist - Herb Reichert of Stereophile heard it about 8 months ago in Sea Ranch, CA and said it was the best audio transducer he has ever heard.

Here are some pics of the cabinets which master carpenter Jeff McCabe is finishing for me, and the drivers.  The speaker is bi-amped using a Pass Aleph 5 on the bottom, and a First Watt J2 SIT amp on the top.  I will receive the cabinets from Jeff in about 1 week.  The only change I made from Pass's design is the use of a 1/2" thick piece of clear acrylic instead of 3/4" birch plywood.  (The acrylic has a much higher density but lower modulus - great for damping.)  The crossover is under construction at Casa de la Binger and should be ready in a couple weeks.  It includes equalization to flatten the driver response out to +/- a couple dB from 40Hz to 20KHz. 

I am also looking at adding a dipole set of Coles Supertweeters at 8Khz and up to improve the Cube Audio driver's high frequency polar response.  The last picture is a 2001: a space odyssey inspired layout of the drivers.  I expect to be ready for an audition by about Thanksgiving time.  I will set a date (probably a Sat. afternoon / evening) in about 1 week.


(https://www.audiocircle.com/image.php?id=200672)

(https://www.audiocircle.com/image.php?id=200673)

(https://www.audiocircle.com/image.php?id=200674)

(https://www.audiocircle.com/image.php?id=200675)




Title: Re: Magnepan LRS
Post by: Blackmore on 10 Nov 2019, 12:40 am
Can’t wait to hear both of these.  Which Eminence woofer are you using? 

Mark
Title: Re: Magnepan LRS
Post by: dcbingaman on 10 Nov 2019, 02:56 am
It’s a Definimax 15 - 8 ohm version. 

The star is this crazy Cube Audio 8” FC8 Driver - it is the most innovative direct radiator / voice coil driver I’ve ever seen.  Very linear and no hysteresis.  It uses a spider made of phenolic “leaf springs”, but shaped like a set of spiral galaxy arms.  Very cool.
Title: Re: Magnepan LRS
Post by: Blackmore on 10 Nov 2019, 02:57 am
Nice!!
Title: Re: Magnepan LRS
Post by: dcbingaman on 17 Nov 2019, 10:58 pm
The SLOB's are assembled !  All I have to do is wire them up to the speaker terminal and finish the crossover.  When do youse guys want to get together ?  I'm thinking the weekend after Thanksgiving or the weekend of Dec. 14/15, 2019.  Lots of fun stuff to show you !

(https://www.audiocircle.com/image.php?id=201000)





Title: Re: Magnepan LRS
Post by: genestl on 18 Nov 2019, 03:31 am
I will bring bier.
Title: Re: Magnepan LRS
Post by: rollo on 18 Nov 2019, 06:35 pm
  They look sweet. You guys have fun. Nice work BTW.


charles
Title: Re: Magnepan LRS
Post by: MickeyBoy on 18 Nov 2019, 10:52 pm
I have a pair of LRS speakers that just did not work out in my room. I have had a pair of Magnepan MGIIIa's for over 25 years, so I know & love Magnepans.  I am planning to return them to Magnepan under the home trial arrangement.   I hate to do this & make such a good company "eat" them. So I am willing to sell them for $600. There is nothing wrong with them, cosmetically or otherwise. To the contrary they are typical Magnepan quality, broken in about 30-50 hours.

I can deliver them during Thanksgiving as I will be in the STL area then. I live in Columbia, MO. I don't want to wait too long to return them.
Title: Re: Magnepan LRS
Post by: dburna on 19 Nov 2019, 12:40 am
The SLOB's are assembled !  All I have to do is wire them up to the speaker terminal and finish the crossover.  When do youse guys want to get together ?  I'm thinking the weekend after Thanksgiving or the weekend of Dec. 14/15, 2019.  Lots of fun stuff to show you !

(https://www.audiocircle.com/image.php?id=201000)

Am curious -- is there a crossover to the SLOB speakers? Or do both woofer and full-range connect directly to the speaker terminals? It is not possible to tell based on these photos if there is a crossover involved.....or what kind it is.

Thanks, -dGB
Title: Re: Magnepan LRS
Post by: dcbingaman on 19 Nov 2019, 09:48 am
The speakers are bi-amped.  The active crossover was custom-designed by Nelson Pass and had EQ for each driver, as well as a 2nd-order Linkwitz-Riley filter set.  The crossover frequency is about 80 Hz.  The drivers are connected to the amps in positive phase.  The Cube driver is quite efficient and is driven by an SET or a JFET power amp like a First Watt J2.  The low pass is driven by a suitable 60-100W power amplifier like a Pass Aleph or First Watt F5 Turbo (about 140W). 

The crossover has stereo pots for both low and high pass.  The pots are set using a pink noise source (CD), a calibrated mike and an RTA.
Title: Re: Magnepan LRS
Post by: pinkfloyd4ever on 19 Nov 2019, 09:16 pm
Nice! I'm definitely excited about this one.

When you say the weekend after Thanksgiving, do you mean Nov 29-Dec 1? Or Dec 7-8? I could do Dec 1, 7, or 8th.

December 14-15 works for me but it might be a little too close to Christmas for a lot of people?
Title: Re: Magnepan LRS
Post by: dcbingaman on 20 Nov 2019, 02:42 am
I am thinking the weekend of Nov. 28-29 OR Dec. 14-15.  I have a couple conflicts on Dec. 7-8.  I'm good for Saturday or Sunday - let me know what works for you guys.
Title: Re: Magnepan LRS
Post by: dcbingaman on 20 Nov 2019, 02:46 am
Check that - I meant the extended weekend of Nov. 29-30.  I have an SLSO Concert on Sunday Dec. 1st, and a Wash U. concert on Dec. 8th.  (How time flys by !!)
Title: Re: Magnepan LRS
Post by: pinkfloyd4ever on 27 Nov 2019, 01:51 am
Wow no one else is interested in this?

I could maybe do the 14th or 15th, but it might be best to wait till after the holidays at this point?
Title: Re: Magnepan LRS
Post by: popthinker on 29 Nov 2019, 01:07 am
I'm up for after the holidays sometime.
Title: Re: Magnepan LRS
Post by: dcbingaman on 29 Nov 2019, 11:56 pm
Hi, guys.  I am now thinking after the Holidays in the New Year.  Everybody is too busy between now and the blessed event.

I should have everything soldered and calibrated by then.  I am thinking maybe Jan. 4th, 11th or 18th.  Let me know what works best for youse guys (and gals !!).
Title: Re: Magnepan LRS
Post by: Blackmore on 30 Nov 2019, 01:31 am
I’ll chime in first by choosing the 11th.  Thanks
Title: Re: Magnepan LRS
Post by: chalmersiv on 30 Nov 2019, 12:03 pm
if this is open to everyone I would like to do 12-11...gordon
Title: Re: Magnepan LRS
Post by: pinkfloyd4ever on 10 Dec 2019, 06:39 pm
Not sure what my schedule in January will look like at this point, but probably pretty open, so I think any of the above dates should be good.
Title: Re: Magnepan LRS
Post by: dcbingaman on 11 Dec 2019, 06:34 am
Hi, guys and gals (AKA Major Dudes and Dudettes).  Based on all the recent craziness, I have settled on Saturday, Jan 11th, 2020 from 2:00 pm until whenever for my Open House.  Audio food and drink will be provided.  Please PM me to RSVP and for directions.

Attractions: Speakers: Magnepan LRS, Pass SLOB and Spendor SP1 speakers, Vandersteen 5.1 HT with new Sony 4K projector.  Amps: First Watt J2, PassDIY Sony VFET, Dynaco Stereo 70 Block 3, Pass Aleph 5, PassDIY F5 Turbo V.2. Preamps: Pass Nutube, Broskie Aikido, Vinyl: Denon DP-75 / Jelco SA-750 + Ortofon SPU, VPI HW-19 Mk. IV / FR-64fx + Koetsu Urushi Gold, SOTA Sapphire / Sumiko "The Arm" + Miyajima Shilabe.  Digital: various sources with Meridian DAC's.
Title: Re: Magnepan LRS
Post by: SteveFord on 26 Jan 2020, 11:42 pm
And then what happened?
Title: Re: Magnepan LRS
Post by: pinkfloyd4ever on 1 Feb 2020, 11:54 pm
And then what happened?
It was a great time and the LRSs were freaking awesome! I haven't been able to stop thinking about them since. Really been trying to figure out how I could make them work, but I just don't have the space, or a powerful enough amp.

Don, were you running your LRSs with subs when we were there? And with the J2 or or the Aleph 5? I thought it was the J2, but from what I've been reading a 15 wpc amp would never be near enough power to make those sound as good as they did.
Title: Re: Magnepan LRS
Post by: Wind Chaser on 2 Feb 2020, 12:58 am
Really been trying to figure out how I could make them work, but I just don't have the space, or a powerful enough amp.

And that's the rub. A lot of people will continue to find this out the hard way.
Title: Re: Magnepan LRS
Post by: smargo on 2 Feb 2020, 05:03 am
And that's the rub. A lot of people will continue to find this out the hard way.


right - you def need at least 100 watts - dont even be on the fence on this one - but wind chaser if you do have the right wattage

their awesome
Title: Re: Magnepan LRS
Post by: dcbingaman on 5 Feb 2020, 10:59 am
Hi, guys.  I was running the LRS's with an Aleph 5.  An Aleph 4 would be even better.  These babies dig current !  Also they were crossed over at 50 Hz to a single Outlaw Audio 12" subwoofer and balanced using an RTA.  Great combination.
Title: Re: Magnepan LRS
Post by: dcbingaman on 22 Mar 2020, 05:03 am
Hi, Guys. Since the Bat virus is making everyone Bat $hit crazy, I, like ya'll, am cooped up in the House for the next few months.  I decided to see if Wendell Diller was up to anything good with this "30.7 for Condos" idea of using stereo dipole dynamic woofers in place of the large bass panels on the regular 30.7 model.  It doesn't take a rocket scientist to figure out that a 30.7 midrange and tweeter panel is essentially a larger version of an LRS.  The missing element is the dipole woofer.  Wendell supposedly has a 4 x 6.5D" woofer array on an open baffle of some geometry which nobody is allowed to photograph.  Things that make you go Hmmmmm.....???

Rather than try to guess and duplicate that, I decided to use a proven setup from Siegfried Linkwitz for his LX521.  Madisound has knockdown cabinets for both the dipole woofer and the rest of the speaker, but they will sell you the dipole woofer cabinet separately.  The drivers Siegfried specified are rather expensive (two SEAS L26ROY 10D' drivers), so I looked at alternatives and found an 8 ohm, 10" aluminum cone driver from Dayton Audio that is better suited than the SEAS driver for the open baffle - the RSS265HF-8.  It has a Vas 50% greater than the SEAS driver and it has a flatter response below 100 hz.  Here's some pics.


(https://www.audiocircle.com/image.php?id=206211)

(https://www.audiocircle.com/image.php?id=206212)

DSP - I acquired a miniDSP 2x4 HD which has two inputs and four outputs and has 24 bit / 96Khz A/D, processing and D/A.  Very cool and easy to program.  I am using Linkwitz's curves for the woofer EQ and crossing over to the LRS panels at 80 hz at 24 dB / octave.  Bass boost at 20 hz is about 12 dB.  I am using a Emotiva A-300 for the woofers (300W into 4 ohms - the woofers are run is parallel) and my Pass Aleph 5 for the LRS's (~100W into 3 ohms).  I am still working on the second dipole woofer so I haven't hooked it all up yet. 

When I get to the audition stage I will give you an update.  I am using a calibrated mike, a pink noise CD and a RTA app on my iPhone to set the levels - works pretty good with the Outlaw audio sub I am using now with these wonderful little LRSes.  I'd love to have you guys over to hear these again, but the social distancing thing will keep us apart for a few more weeks.  I CAN post RTA images here as soon as I get them done.  Stay tuned !!
Title: Re: Magnepan LRS
Post by: pinkfloyd4ever on 23 Mar 2020, 09:39 pm
Nice! Looks interesting and I bet it will sound awesome. Definitely looking forward to this social distancing/shelter-in-place being over but I'm afraid it may be a longer than we're hoping.

Yeah I'm getting pretty close to digging out the parts for some projects that I had given up on ever actually completing with all the time at home. Maybe I'll finally get started on restoring my Fisher 500c!
Title: Re: Magnepan LRS
Post by: dcbingaman on 14 Aug 2020, 09:43 am
OK guys, I have some major news.  Jeff McCabe and I have built the first pair of Little Dipole Woofers (LDW) for Magnepan's wonderful Little Ribbon Speakers (LRS).  This is a slot-loaded dipole which sits right behind the panel on MagneRiser stands and radiates through a 3" x 10" slot underneath the panel.  The 10" Dayton Audio driver is powered by a Dayton Audio 250W amp with built in DSP  with a high pass for the LRS - similar to Wendell Diller's "30.7 for Condos", but better integrated geometrically.  I am halfway through tuning, but I have gotten a flat response down to 32 Hz and they integrate so well with the Maggies you can't hear the transition.  They give the Maggies Cajones like a cone speaker, but preserve the magic Maggie lower midrange with no boom or mud in the response.  You've never heard an acoustic bass sound this realistic in a loudspeaker - they are that good.

Here's a picture....more soon, but Jeff and I intend to build these in production for LRS owners via direct sales.  Availability and price TBD, but affordable !!


(https://www.audiocircle.com/image.php?id=213173)

(https://www.audiocircle.com/image.php?id=213174)

Title: Re: Magnepan LRS
Post by: Blackmore on 14 Aug 2020, 11:35 am
Nice work Don!!!!!!!
Title: Re: Magnepan LRS
Post by: Jon L on 14 Aug 2020, 03:45 pm

Here's a picture....more soon, but Jeff and I intend to build these in production for LRS owners via direct sales.  Availability and price TBD, but affordable !!

(https://www.audiocircle.com/image.php?id=213174)

Very niiccee... There is no reason you can't use these dipole subs with other Maggies or other dipole speakers, right?  :thumb:
Title: Re: Magnepan LRS
Post by: hdspeakerman on 14 Aug 2020, 07:11 pm
Don,
Congrats and good luck with your new enterprise!
Title: Re: Magnepan LRS
Post by: dcbingaman on 14 Aug 2020, 07:12 pm
The LDW was designed to work with the LRS, but it can be used with any panel speaker including the bigger Maggies, and potentially the Quad electrostatics, although it will play much louder than the Quads can manage.  The DSP in the SPA 250 DSP amp is quite capable and can be adapted to whatever crossover characteristics you desire.  Right now we are using 24 dB/octave slopes in the digital domain and keeping the woofer and panel in positive phase.  The open baffle woofer requires a unique EQ to get flat response in the room.  I started with Siegfried Linkwitz' s EQ curves and went from there - they were pretty close.

The DSP is programmed with a great interface that is accessed via USB port using a PC, but it also has a small alpha-numeric display built in the the plate with a multi-function knob to allow for matching the gain of the high pass amplifier and the efficiency of the panel speaker to the woofer using a simple iPhone based Real Time Analyzer.  The DSP also can time-sync the woofer and the panel so that the wave comes out simultaneously from the port and the panel.  This is a big advantage.
Title: Re: Magnepan LRS
Post by: dcbingaman on 14 Aug 2020, 07:49 pm
One other point not obvious from the photos - this are true dipole woofers in that the front of the driver faces rearward and radiates out of the back of the cabinet.  The back of the speaker radiates out of the forward-facing port with is about 35% of the area of the 10" driver aluminum cone.  The port impedance provides about a 3 dB gain to the front wave reducing the amount of EQ required, but the system still acts as a dipole and provides the same radiation pattern as a dipole panel speaker, with ZERO cabinet resonance.  The DSP allows a time-sync between the panel and the woofer so that the wave emerges in sync and in-phase with the panel output. 

The result is seamless bass.  After a couple days of listening and tweaking I can say that Wendell Diller is right, a dipole woofer woks MUCH better than a general purpose subwoofer with the LRS speakers, because of the radiation pattern and the lack of any cabinet resonance.  I have never heard standup bass sound better on any speaker, including my Vandersteen Quatros which are integrated with a 5-speaker Audiokinesis SWARM distributed subwoofer array.
Title: Re: Magnepan LRS
Post by: dcbingaman on 17 Aug 2020, 05:25 am
The LDW DSP calibration is done.  The results are provided below.  The LDW's extend the LRS low end flat down to 27 Hz (the Dayton Audio free air resonance frequency) with a dynamic DIPOLE woofer.  All it takes is a 250W amp, a 600W dynamic woofer and digital signal processing courtesy of Dayton Audio. 

Have NEVER heard string bass sound as realistic in 40 years as an audiophile, including many of the BIG speakers.  The solution is also DIRT CHEAP.  The speakers are headed out on a listening tour west and then east but will be back this fall.  When this COVID-19 catastrophe is over we'll get back together at Casa de Binger for beers, Cyrus Chestnut and a new product introduction, the VPE Aerospace Little Dipole Woofer (LDW) built especially for the magnificent Magnepan Little Ribbon Speaker (LRS).  Bring your checkbooks. LOL !


(https://www.audiocircle.com/image.php?id=213323)
Title: Re: Magnepan LRS
Post by: sturgus on 18 Aug 2020, 02:41 am
Kool!!! Thinking of buying a pair of LRS myself. How much will a pair of the woofers with DSP cost to build?
Title: Re: Magnepan LRS
Post by: dcbingaman on 18 Aug 2020, 02:44 am
Great question, Sturgis.  VPE can build a set for you, but haven't set a price yet.  I'll PM you with cabinet, driver and amp/DSP specifications and costs.  They are relatively affordable compared to high-end subwoofers.
Title: Re: Magnepan LRS
Post by: dcbingaman on 28 Sep 2020, 03:11 am
The LDW Model 1's are now in production.  $795.00 for one or $1495.00 for stereo pair.  Here is some pics and a story !!
(https://www.audiocircle.com/image.php?id=215211)

(https://www.audiocircle.com/image.php?id=215212)

(https://www.audiocircle.com/image.php?id=215214)

(https://www.audiocircle.com/image.php?id=215215)
Title: Re: Magnepan LRS
Post by: emailtim on 29 Sep 2020, 12:38 am
I have a couple of observations/questions if you don't mind.

This looks more like a U-Frame with 1 side tapered, longer D and turned around backwards than the Nelson Pass's SLOB project (e.g. no large front L/R baffle, different single driver orientation, no force cancellation).

(https://www.hifizine.com/files/2012/12/U-frame.png)

A U-Frame has a cardioid response on the driver side.  The OB/dipole cancellation happens at the back port. 

Since the U-Frame is turned around backwards, the cardioid response would appear to be firing backwards towards the front wall, not towards the listener.

(https://www.audiocircle.com/image.php?id=213175)

The cancellation at the Maggie interface may reduce any force on the Maggies.

Can you describe why it is NOT a tapered U-Frame and why it is a SLOB ?

Also, can you please clarify if and specifically what parts Nelson Pass has designed on this project ?  There appears to be some question/confusion on the web if he was directly involved in designing it or not or if it was inspired by one or more of his other projects (e.g. your plexiglass speaker clone).

(https://www.audiocircle.com/image.php?id=201000)

https://www.stereophile.com/content/gramophone-dreams-26-nelson-pass-harmonic-distortion-page-2 (https://www.stereophile.com/content/gramophone-dreams-26-nelson-pass-harmonic-distortion-page-2)

(https://www.stereophile.com/images/119gdreams.passsystema.jpg)
(https://www.stereophile.com/images/119gdreams.speakerbac.jpg)

Thanks much.
Title: Re: Magnepan LRS
Post by: dcbingaman on 29 Sep 2020, 05:27 am
The port is 1/3rd the size of the driver and has a higher acoustic impedance than the woofer face - hence it has higher velocity and about 3 dB greater output than the woofer front face which faces the wall.  If you look at Pass's SLOB design it is quite similar.  The front face of his horizontally oriented Eminence driver feeds the front-facing slot which is isolated by the baffle and the sidewalls from the driver open backside.  In our case we use the back of the driver to feed the slot and the front of the driver radiates rearward. 

It works and Pass approves the design.  The shape of the cabinet is designed to match the Maggies on stands and we do indeed use the Maggie panel as our baffle board.

We would be happy to sell you a pair for your panel speakers !  You'll love them.