dspMusik for VMPS RM50's

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HAL

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dspMusik for VMPS RM50's
« on: 23 Jul 2016, 03:46 am »
Just got home from Avoosl's after a listening session with his updated dspMusik digital crossover for the VMPS RM50 speakers.  Switched to the minimum phase soft knee filter for the latest version and to me it sounds much cleaner overall than with the minimum phase apodising filters in the Wolfson Micro WM8742 DAC's.

Doo Wop Friday has never sounded so good with a chaser of Elvis and Tartini. 

His MS-1 is loading the new block diagram into my demo dspMusik, so I can update his unit with the new version.  Will be doing that tomorrow.

He also has MathAudio Room EQ running in Foobar2000 for room and speaker correction with the first measurement.  Will be interesting to hear this as another step in the trials.

Overall a fine Friday night at the Inn.   :D

James Romeyn

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Re: dspMusik for VMPS RM50's
« Reply #1 on: 23 Jul 2016, 05:15 am »
I estimate there are three pairs of RM50s in existence.  Does your friend/the RM50 owner know how many pairs Brian made? 

Performance wise, RM50 was Brian's best work, by considerable margin.

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Re: dspMusik for VMPS RM50's
« Reply #2 on: 23 Jul 2016, 12:14 pm »
James,
He only knows of three.  They were all at CES's.  The oak finish pair, his black pair with the bottom passive radiators and the black pair with the side mounted passives.   

He heard one pair was not working at one owners, as his was when they arrived.  I rebuilt his pair as there were many problems.  Now they even have the original woofers from CES, as they had been changed before they were shipped.  He got the originals while Brian was still alive along with spare tweeters and mids.

These sound so much better now with the MS-1 and dspMusik than the DCX2496. They sound very good indeed! 


Avoosl

Re: dspMusik for VMPS RM50's
« Reply #3 on: 23 Jul 2016, 04:33 pm »
    I would like to confirm all that Rich said about the RM50s - the number of them, their wonderful sound, and the
sad fate of their damaged delivery, wholly unrelated to shipping and handling.  The latter, despite my best investigative
efforts and questioning of the principles in the case only adds to their magic, oddly enough.

    After their showing at CES 2011 I bypassed my original intent to opt for the final edition of the Super Tower IIIs as a
replacement for my old Super Tower IIIs from around 1990.  This was partly from quizzical, oracular-like and ambiguous
replies from Cheney himself, and partly from the over-the-top reviews of people who heard them at the show.  Still, it was
a hard decision, as my listening to the ribbonized version of the STIIs at a now-defunct DC dealer's place was still in my
ears and mind as a supremely fine sound.

    When they arrived in perfectly packed condition with no possible damage from shipping I was elated till I hooked them
up to find that the woofers were different, were wired out of phase, and one wasn't even wired, and that several of the
midrange panels were damaged, old, and not working properly.  Thanks to Rich, and shipments from Brian of replacement
drivers, all was fixed up, eventually.  The mystery of what happened to them between the show and their arrival at my
house is unsolvable.

     The great sound finally salved my initial disappointment and dismay, to say the least.  In fact, I wasn't sure what was
making them sound so good, merely from an inspection of the drivers and their placement.  I'm still unclear, though not
greatly caring about that.

     When Rich suggested using the soft-knee minimum phase filter option on the chip in the dsp Music crossover engine,
I was quite surprised to find even greater clarity and pleasing resolution on all I've heard.  I wonder what Brian would
have thought to hear them now!  Would that some knowledgeable speaker builder could analyze and deduce what it is
that makes them sound so good, and build something from that so more could enjoy their capability.   

James Romeyn

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Re: dspMusik for VMPS RM50's
« Reply #4 on: 23 Jul 2016, 05:55 pm »
Did you notch the neo planar mid range panel 1kHz resonance?  IIRC the peak is 6 dB, where the ear is most sensitive to such resonance. 

For me personally, the RM50 is the only VMPS I heard w/this mid range peak notched out.  I should clarify this when I say the RM50 is his all time best audio performer.  Some members here have the earlier RM60 w/Brian's best sub towers and the mid range peak flattened, which likely outperform RM50.   

Brian conflated the terms "planar" and "ribbon."  He used both types of drivers for mid and treble range.  For reasons of clarity, IMO it would have been better if he always differentiated between the two architectures.

RM50 owners are welcome to call me for a confidential tip to audibly improve performance.  It's easier to explain live.  The RM50 is the only VMPS model for which this tip works.


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Re: dspMusik for VMPS RM50's
« Reply #5 on: 23 Jul 2016, 06:16 pm »
James,

I put in the dip in response as Brian had done in the RM50 DCX2496 filters.  They are electrically the same, except the output DAC's also have minimum phase filters for reconstruction.  Something the DCX2496 does not have and critical to keeping the dspMusik sound quality of the digital crossover better than any other unit I have heard.   

Hope RM50 owners take you up on your phone call offer. 


HAL

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Re: dspMusik for VMPS RM50's
« Reply #6 on: 24 Oct 2017, 02:19 am »
Just completed programming the new dspMusikLCD digital crossover for Avoosl's RM50's.

Will be taking it to his place tomorrow for listening trials in comparison to his dspMusik RevC system.  He has been very happy with the original since it was installed.  Now to see what the next generation unit sounds like with his setup.


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Re: dspMusik for VMPS RM50's
« Reply #7 on: 24 Oct 2017, 03:46 pm »
Just setup the dspMusikLCD system in Avoosl's system with the RM50's.  Listened to some very familiar tracks, and to me the best sound to date in his room. 


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Re: dspMusik for VMPS RM50's
« Reply #8 on: 24 Oct 2017, 05:27 pm »
Picture from Avoosl's setup for the install of the dspMusikLCD.



titaniumheads

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Re: dspMusik for VMPS RM50's
« Reply #9 on: 25 Oct 2017, 03:13 pm »
I cannot figure out the problem with the tweeters not working in My VMPS RM/X speakers with passive crossovers. How difficult would it be to convert these to active with  the dspMusik and do you feel I could get an improvement in the sound?

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Re: dspMusik for VMPS RM50's
« Reply #10 on: 25 Oct 2017, 03:21 pm »
To use the dspMusikLCD with the RM/X, the internal passive crossover would need to be bypassed and driver connections made available on the rear for amp connections.  Since I have not seen the rear setup on the RM/X, not sure how hard that is.  Would most likely need a full triamp setup since it is ribbon tweeter, multiple Neo planar mids and woofers.

If you have a rear picture, that would help to show the existing connections.

titaniumheads

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Re: dspMusik for VMPS RM50's
« Reply #11 on: 25 Oct 2017, 04:56 pm »
They are on their backs but here is a picture of the inside.Ignore the 12 gauge clear jacket copper wire going to the Lpad, that was for testing.

 The green and blue wire go to the tweeter, red wires to the midranges and the big silver wire to the woofers. I would just have to install two additional terminals for amp connections and I am assuming I  would bypass everything including the L pads? Would the order be 
Music server>Microrendu>dspMusik>Amps> Speakers. So I would not need my pre-amp or Dac?

HAL

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Re: dspMusik for VMPS RM50's
« Reply #12 on: 25 Oct 2017, 05:07 pm »
titaniumheads,
Basically that is correct.  However with the ribbon tweeters, they should have a series capacitor for DC and low frequency response protection, unless the amps are DC servo controlled for protection after the digital crossover.

First step would be to measure the existing crossover at the connection of the drivers to the crossover with PocketCLIO that I can send.  After the response data is made, then I can build a digital version of the passive crossover.

The measurements with the PocketCLIO may show why the tweeter system is not working.  Could be a few things going on.  I see a person with RM40's having ribbon problems as well.

The next question is if the microrendu works with ASIO compatible USB DAC's like the dspMusikLCD.  No preamp needed as the dspMusikLCD has a 8 channel DAC volume control with 0.5dB steps over a large adjustement range.  Input selection and volume are all remote controlled.

Probably should start an RM/X thread since this is for the RM50 comments.

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Re: dspMusik for VMPS RM50's
« Reply #13 on: 25 Oct 2017, 06:45 pm »
Have you tested the two L-Pads for correct resistances and operation?  Since both are not working, might be a good place to start.  They are usually a weak point in speaker crossovers.

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Re: dspMusik for VMPS RM50's
« Reply #14 on: 26 Oct 2017, 06:33 pm »
Just read a great email from Avoosl on the dspMusikLCD with the RM50's.  Fun when I get emails like this!

Hope he will post it here for folks to read.