+ Reply to Thread
Page 1 of 4 123 ... LastLast
Results 1 to 10 of 35

Thread: Yamaha NS-1000M A Fresh Start

  1. #1
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,469
    I'm Ken.

    Default Yamaha NS-1000M A Fresh Start

    A Fresh Start.

    I just can't get away from the fact that I like so much about the NS-1000m.
    The re-cap I completed, using more neutral capacitors helped the overall presentation, but I decided to make another attempt at sorting out my minor dislikes.

    Over the years I have found more 2-way systems that I feel happy with than 3-way. I often find a resonant distortion exists around the crossover point on a 3-way, at the hand over between woofer/midrange. This can add a nasty edge to male vocals and fingers on strings etc.
    While taking some measurements of capacitors, to satisfy my curiosity regarding Equivalent Series Resistance (ESR) values, a possible cause of this distortion came to mind.

    The following ESR values were measured using Dayton Audios Test System (DATS).



    I took these ESR measurements from capacitors of 30uF. This is in the 20 to 30uF bracket, not uncommon for the series cap in a low order filter, used for the midrange High Pass on a 3-Way. This is usually the biggest value on the crossover that is in the signal path.
    The first thing I noticed, was contrary to what I have been reading on the forums, there is not a massive difference between the capacitor types. The Alcap Lytic, Mundorf Low Loss (LL) Lytic and Ansar Supersound PP caps all have remarkably similar ESR curves with only small differences. The second and most noticeable thing, was that the ESR values rise substantially below 500Hz. This is the area where the woofer/midrange crossover area lies on a 3-Way speaker, a 2-Way would cross at say 2kHz where the ESR levels are much lower. It might be a coincidence, but I wondered if this could in some way be linked to the resonance that hampers my listening experience on the NS-1000m and previously on the Celestion 66 Monitors.

    I decided to take some measurements of lower value caps.



    The 4uF Alcap Lytic and Sonicap PP capacitor, also show similar ESR curves, with the Lytic having only slightly higher values, 21.3ohm against 19.7ohm at 2kHz for instance. It would seem though, that the smaller the cap value, the higher its ESR. I measured a 0.2uF and it had a massive ESR, over 1kohm at 200Hz and going off the scale at lower frequencies.
    To try and rule any of this out, in terms of having a detrimental effect on the sound, I decided to run an experiment, using a passive crossover that doesn't use a cap, running into a large ESR value, in the midrange signal path. I would create a line level active filter operating at 500Hz for the woofer/midrange handover and use the stock passive elements for just the mid/tweeter handover at 6kHz, where ESR values are much lower.





    I had a spare pair of 3-Way active crossover boards from KMTech, I modified them to work as a 2-Way, crossing at 500Hz. Basic polyester caps, but good enough for a quick look-see. I borrowed the discrete op amps from another board.



    This diagram shows how it would be set up as a system.



    I cobbled together a set up, as per the diagram, by disconnecting a leg on the unused components in the stock passive crossover and using the modified active filter, just to see if there was any millage in the idea.

    It works, and very well, with a much smoother hand over at woofer/midrange, without any noticeable resonance. My reasoning may have nothing to do with it, who knows, but the positive results from this little experiment, can't be denied. I bet your thinking, why not go fully active? The synergy between mid/tweeter in passive form is extremely good and it is not likely to be bettered by going active. Basically, if it ain't broke, don't fix it! The obvious reason though, is that this set up uses only four channels of amplification, instead of the six needed to go fully active. This arrangement has the signature sound from the midrange/tweeter that the passive filter delivers, with the benefits of a cleaner hand over at woofer/midrange and a separate Amp to drive the woofers, which has its own advantages.

    While I had this lash up hooked up, I decided to put another issue to bed, digital or analogue active?

    The Analogue filter above uses a LR 24dB/Octave slope at 500Hz. I set up a similar filter on my Hypex DLCP (DSP) and did a shoot out between them and the stock passive. My conclusions? The passive has the ability to get to the heart of the music and to express the finer detail in a natural way. Its down side is the edgy resonance around 400Hz on voices like Gregory Porters. The Semi-Digital Active set up is by far the smoothest, with very clean sounding crossover points, but somehow it doesn't involve me like the passive and feels less interesting to listen to. The Semi-Analogue Active is almost as clean as the Digital, but it grabs my attention and draws me in like the passive.

    So Analogue Semi-Active it will be, this arrangement also works extremely well with my Turntable, where the digital filters do not.

    Next, which Woofer, the Yamaha or the Skanspeak.

    I set the two woofers up, one on top of the other and just swapped leads at the amp between the two, the passive x-over for the Mid/Tweeter and the analogue active for the woofers and of course, as a Pre-Filter for the passive. There was very little difference between the woofers, the Skanspeak seems to integrate just as well as the Yamaha and gives some extra depth when called for. As I already have the Skanspeak woofers, I may as well use them. They really are cracking drivers, as this near field response I measured shows.



    Skanspeak 30W/4558T00 Bass driver.

    Remarkably flat, +/- 1dB from 32 to 500Hz with an f3 of 29Hz in its 55L sealed cabinet, even better than predicted. Larger power handling and a massive xmax put it in another league to the venerable Yamaha Woofer I measured below.




    I'm doing lots of listening to both bass drivers before making my final choice.

    If I do choose the Skanspeak drivers, rather than bodge the Yamaha cabinets, a new pair will be made. Meanwhile, I'll work on the crossovers, both passive and active. I'll use Rod Elliotts active board, its the same basic filter circuit as the KMTech I've been using, but it has both Left/Right on the one PCB. It also has provision for balanced inputs and uses single channel attenuators on each output, which allows both amplifier and Left/Right channel matching. Also the board has the facility for output buffers, so all bases covered on these PCB's. The associated passive crossover, will be much simpler than the stock item, just two caps and two coils on each, I may as well make provision for a resistor network to replace the level controls. Again, I don't want to bodge the original boards, so a new x-over using good quality parts is in order.

    I've summarized my findings and the work carried out, it actually took a couple of weeks to modify, try out and reach these conclusions.





    I selected Jantzen Superior Z-Caps, as they are supposed to be (like the basic Mundorf Mcap MKP I tried) very neutral, but also superb at handling high frequencies. As only the Tweeter cap is in the signal path I think it's a sensible choice.





    This is my layout.
    As previously stated, its the stock Yamaha circuit and values, as used for the Mid/Tweeter crossover at 6kHz.
    By using the line-level Active Pre-Filter, I've taken the big bank of (21uF) caps out of the signal path of the midrange driver.
    The board is point to point and uses a star ground, decent caps and air core coils. I've taken the longer wire runs under and over on the board to stop them flapping about, sticking them down with hot melt or using cable ties doesn't look very tidy. I've used spade terminals for the input/output connections, once the development is completed, the final build will have the wires soldered at these connections.

    I need to order the parts and build these crossovers as a first step.
    Last edited by Qwin; 24-01-2018 at 23:31. Reason: typo
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + AT 33PTG II / AQVOX Phono 2 CI / Pro-Ject Pre Box RS / ESP Active X-Over / Nakamichi AVP1 Power / Modified semi-active Yamaha NS1000M Speakers / Stello CDT100 Transport / NAD M51 DAC.

  2. #2
    Join Date: May 2012

    Location: Dagenham Essex

    Posts: 7,927
    I'm I'mteachingmarcotheartofpishanto.

    Default

    WOW , you are clever doing things like this

    Respect
    Last edited by Audio Al; 25-01-2018 at 05:22.
    Music , fills the gaps between silence !

    TAT Sale post Leader " Marcos Mentor "

    Also a pishanto specialist confirmed by Head Daftee

    Real name " Allen " or "Zoomer Nut”, “Numpty Napper”.

    ±± KEEP IT REEL

  3. #3
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 241
    I'm Sandro.

    Default

    What software are you using I see DATS ...
    Can U please post same more details about it ?

  4. #4
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 20,687
    I'm Martin.

    Default

    Interesting stuff. Have to say I could not hear the midrange issue that you describe when listening to your modded Ditton 66 but then you hear a lot more listening over time and in your own listening room. I think I am also leaning towards the idea that passive crossovers, or at least fully passive, are the biggest bottleneck and the biggest cause of sound quality issues.
    Martin



    Current Lash Up:

    Technics SL1200P CD Player * NVA P90SA passive pre / Krell KSA50S Power amp * JM Lab Electra 926 loudspeakers *



    'The best I advice I ever received was to always remember that no-one else has any idea what they are doing either.'

  5. #5
    Join Date: Jan 2009

    Location: Sheffield - UK

    Posts: 5,980
    I'm Mark.

    Default

    I’m afraid I don’t see the logic in having two crossovers in series with the mid and tweeter.

    I think slight lower mid congestion can be cured by using a steeper crossover from the bass driver (3rd rather than 2nd order).

    100% Analogue

  6. #6
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,469
    I'm Ken.

    Default

    Quote Originally Posted by Bksabath View Post
    What software are you using I see DATS ...
    Can U please post same more details about it ?
    Just search on YouTube I think there are demos of DATS, I got mine from Parts Express from across the Pond, there is info on their site too.
    I also have REW and a built in measuring facility within the Hypex HFD (Hypex Filter Designer) software, that came with their DLCP (DSP) unit.
    Oh, and the demo version of ARTA.
    Last edited by Qwin; 24-01-2018 at 23:24.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + AT 33PTG II / AQVOX Phono 2 CI / Pro-Ject Pre Box RS / ESP Active X-Over / Nakamichi AVP1 Power / Modified semi-active Yamaha NS1000M Speakers / Stello CDT100 Transport / NAD M51 DAC.

  7. #7
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,469
    I'm Ken.

    Default

    Quote Originally Posted by YNWaN View Post
    I’m afraid I don’t see the logic in having two crossovers in series with the mid and tweeter.

    I think slight lower mid congestion can be cured by using a steeper crossover from the bass driver (3rd rather than 2nd order).
    The mid already has two crossovers in series on the passive as it is a band pass, I have simply replaced the passive High pass element with a line level one.
    I take your point about doubling up on the tweeter, but in my opinion, it's still sounds better than the 30ohms or more ESR that the 21uF series caps add to the midrange at the cross over region.

    I used my DSP and tried 2nd to 6th Order Butterworth/LR at frequencies from 300 to 600Hz and also different (unequal) slopes for the mid and woofer and what measured and sounded best (to me) was the 24dB/Octave LR at 500Hz which I am now using. This was best with both the Yamaha and the Scanspeak woofers in place, its the midrange driver that runs out of steam at the bottom end, if your not careful you end up with a valley in the response at the crossover region.
    What I have written in this post is about a tenth of what I have actually tried, it would take too long to write up and be boring, so I just give the major events.
    Last edited by Qwin; 24-01-2018 at 23:19.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + AT 33PTG II / AQVOX Phono 2 CI / Pro-Ject Pre Box RS / ESP Active X-Over / Nakamichi AVP1 Power / Modified semi-active Yamaha NS1000M Speakers / Stello CDT100 Transport / NAD M51 DAC.

  8. #8
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,469
    I'm Ken.

    Default

    Quote Originally Posted by Macca View Post
    Interesting stuff. Have to say I could not hear the midrange issue that you describe when listening to your modded Ditton 66 but then you hear a lot more listening over time and in your own listening room. I think I am also leaning towards the idea that passive crossovers, or at least fully passive, are the biggest bottleneck and the biggest cause of sound quality issues.
    I don't think your wrong Martin.
    Trouble is the full DSP route, while having noticeably clean filters, just lacks something and I loose interest in whats playing. I have yet to hear one that does justice to vinyl. The ADC's they use just aren't good enough so digital sources always sound better than analogue. The Hypex DSP sounds slightly better than the miniDSP with an analogue source. But the analogue Active just sounds right, which is why I've partly strayed back to it, the digital is more of a development tool for me now.
    Last edited by Qwin; 24-01-2018 at 23:45.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + AT 33PTG II / AQVOX Phono 2 CI / Pro-Ject Pre Box RS / ESP Active X-Over / Nakamichi AVP1 Power / Modified semi-active Yamaha NS1000M Speakers / Stello CDT100 Transport / NAD M51 DAC.

  9. #9
    Join Date: Jan 2013

    Location: Birmingham

    Posts: 3,728
    I'm James.

    Default

    Hi Ken. How easy is it to swap between the original speakers crossover and the modified version in order to hear the changes you are making?

  10. #10
    Join Date: Jan 2009

    Location: Sheffield - UK

    Posts: 5,980
    I'm Mark.

    Default

    Well, it's an interesting approach and not one I've seen done before. However, the whole signal is still going through the digital crossover. It may be passing on frequencies above a certain point but the signal is still being converted to digital and then back to analogue so it can pass through a further analogue filter. Are you sure you aren't in danger of reinventing the wheel as something that is very slightly oval?

    100% Analogue

+ Reply to Thread
Page 1 of 4 123 ... LastLast



 

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •