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Thread: Semi Active Three Way Speaker Project

  1. #11
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

    Default Update

    The lash up now has 132 hours on it and has settled nicely.

    The original ported box Quads with their original crossover sounded pretty good, I would not have used them if they didn't.
    Mounted on top of my Yamaha's and borrowing their 12" driver for bass duties, they sounded very detailed and revealing, which I like, my last few speakers have been studio monitors and I like this sound. The only criticism I had was maybe a little grain in the upper mids/treble.

    The lash up, with a smaller volume sealed box and blue printed crossover with improved parts, borrowed the Yammies bass as before. The result was as I had expected, a very slight improvement, removing the grain from the top end. In addition, it also has a slightly fuller, richer mid range, not as lean as a monitor now and the bass seems tighter/faster than before. I'm guessing the 4" mid/bass is better damped in the smaller sealed box and its contribution to upper bass and the edges of bass notes is crisper and definitely audible.

    I'm liking the sound - A LOT - most accurate, distortion free, across the whole frequency range, that I've had.

    Initially when I had about 30 hours on the lash up, I was a bit concerned, the sound was not as good as the originals. It lacked body in the mids and was tame in the bass, but this all changed at around 65hrs and the roles were quickly reversed.

    So I've proven the mid/treble drivers suitability and passive/active crossover elements, when paired with the Nakamichi Amp and 12" bass from the Yamaha's. The next step is to acquire the Scanspeak bass drivers and compare their performance. The Yammies are a short throw 12" with a paper cone, the Scanspeak are a long throw with aluminium cone, so a bit of a different animal. I'm expecting deep fast bass from their rigid cone, F3 of 38Hz or better, compared with the Yammies F3 of 53Hz. It's the tone and how they blend with the mid range that concerns me, they look great on paper, very flat from 100 to 1000Hz, but I need to hear them in this set up.

    A couple of things are going to get in the way now, the next NEBO meet is a cert and possibly a try-out at the Wigwam show. I need to have them in some useable state, so they may stay in the current lash up form till these events have passed. I can purchase the Scanspeak drivers and maybe try them in a makeshift cabinet as an interim stage. I'm not lashing out on decent ply and veneer till the new bass is proven.
    Last edited by Qwin; 06-01-2017 at 15:38.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  2. #12
    Join Date: Mar 2010

    Location: Sheffield

    Posts: 2,354
    I'm Simon.

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    Can't help but think a lower resolving mid and tweeter is now ameliorating the previous active XO shortcomings. If a grand piano sounded like a Casio your hifi has issues, other than needing a good subwoofer.

    Have you thought about going fully dsp for your yammy xo with six amp channels up them?
    Kuzma Stabi/S 12", (LP12-bastard) AC, USB controlled bi-phase Class A regenerator psu. Benz LP, Paradise (phonostage). MB-Pro, Mdac, Muse 200, Yamaha NS1000m

  3. #13
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

    Default

    I never said (or meant to imply) my other set up "Sounded" like a Casio.

    I was implying I didn't want this set up to sound like a Casio.
    A lot of speakers/set ups are poor at reproducing grand piano in my experience, both in timber and especially timing, they just can't keep up.

    Forget the Yamaha's folks, they are not related to this project in any way, other than a pair of borrowed 12" woofers, till I can afford the correct ones.

    I mention the Yamaha's F3 as a point of reference from this well known sealed box design. It's just something I and others can relate to in terms of my expected bass performance with this current project.

    To save confusion, I will not mention the Yamaha's again on this thread.
    I will pick up my Active Yamaha thread again, when I have scratched this current itch.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  4. #14
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 200
    I'm matt.

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    Quote Originally Posted by Qwin View Post
    I will not mention the Yamaha's again on this thread.
    Just out of curiosity, did you measure the free-air parameters of the Yamaha woofer in It's enclosure? Just wondered what the QTS (QTC) Is?

  5. #15
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    Quote Originally Posted by fatmarley View Post
    Just out of curiosity, did you measure the free-air parameters of the Yamaha woofer in It's enclosure? Just wondered what the QTS (QTC) Is?
    I didn't but if you have a look on Troels Gravesens site, he posted the T&S for the drivers (QTS = 0.28) when he did his renovation project.
    Makes an interesting read:
    http://www.troelsgravesen.dk/Yamaha-NS1000.htm
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  6. #16
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 200
    I'm matt.

    Default

    Interesting driver. It has a very low Fs, low QTS and high sensitivity. According to my sims It would have a QTC of 0.68 In a 50ltr box (assuming no stuffing material), F3 of around 52Hz and a sensitivity of 92.66dB 2.83v/meter.

    Subjectively, What does the bass sound like? In my admittedly limited experience, a low QTC speaker sounds a bit too lean and lacking punch for my tastes (This Is assuming Troels has measured the T/S parameters correctly - VAS can be tricky to get right)

  7. #17
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

    Default

    Quote Originally Posted by fatmarley View Post
    Interesting driver. It has a very low Fs, low QTS and high sensitivity. According to my sims It would have a QTC of 0.68 In a 50ltr box (assuming no stuffing material), F3 of around 52Hz and a sensitivity of 92.66dB 2.83v/meter.

    Subjectively, What does the bass sound like? In my admittedly limited experience, a low QTC speaker sounds a bit too lean and lacking punch for my tastes (This Is assuming Troels has measured the T/S parameters correctly - VAS can be tricky to get right)
    I don't agree with everything Troels does, but in this instance I think his measured results are accurate, and his findings in general regarding the NS-1000M match my own impressions. The 50L you calculate matches what Troels came up with and matches the volume of the Yammies cabinet. The F3 you calculated matches his findings and also those published by Yamaha in the user leaflet. He says "there isn't much bass below 50Hz" it may plot this way, it does fall off, but I find in the average living room, like mine, there is significant bass reinforcement/room lift. With the gentle roll off associated with a sealed enclosure this means it actually sounds quite deep. I have listened to test tones and 30Hz is still quite present, but at about a third of the output level of 60Hz. As far as punch goes, this tends to be upper bass anyway and is even effected by the mid range, I find they give plenty of punch and slam, rim shots being particularly sharp and realistic. Its only when you get one of those rare droning deep notes that you notice any shortcomings. Bass was as good as my Celestian 66's in my living room, but in a much larger room the 66's still sounded big and powerfull, where as the Yammies lost their presence at the low end.

    I want to keep on topic, so if you want to talk any more about the Yamaha's move it over to my Yamaha thread here:
    http://theartofsound.net/forum/showt...NS1000M-Tweaks
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  8. #18
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

    Default Update

    The Scanspeak 12" bass drivers (30W/4558T00) arrived, Scalford show halted progress, but back on track and hopefully ready in a rough form for NEBO 8. They are fairly substantial drivers with cast alloy frame/basket and a large magnet.



    I just used a library shot, but this is how they come.
    I built some 55L sealed test cabinets, this volume gives a QTC of 0.707 and an f3 of around 36/38Hz.






    I used 18mm chipboard for the construction of this temporary evaluation cabinet, with 18mm MDF for the front baffle and internal brace. All joints were rebated with a router for extra strength and the whole thing was glued without the use of screws or dowels. I used four cargo straps to pull it all up tight while the glue set.






    Driver fits well and all joints pulled up without gaps. I used a generous amount of fibre glass loft insulation to loosely stuff the cabinet.
    Need to get some hours on them now, before evaluating their performance.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  9. #19
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 16,331
    I'm Martin.

    Default

    Looks pretty serious there, Can't wait to hear them.
    Martin



    Current Lash Up:

    Technics SL1200 with Sumiko h/s & Nagaoka MP50 * Firebottle valve MM phono stage * Parasound CDPi1000 * NVA P90SA passive pre / Krell KSA50S Power amp * JM Lab Electra 926 loudspeakers *



    "I hate to advocate drugs, alcohol, violence, or insanity to anyone, but they've always worked for me." - Hunter S Thompson

  10. #20
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

    Default

    Quote Originally Posted by Macca View Post
    Looks pretty serious there, Can't wait to hear them.
    Me too!

    I teamed the Quad mid/tweeter with the 12" bass unit, borrowed from Yamaha the NS-1000m, for the Scalford show and they worked quite well together.
    The room was one of the worst in the place acoustically, but they still managed a decent performance. I'm hoping the Scanspeak will work just as good and give some extra depth to the bass. Still working on the second cabinet, but they will be finished with a reasonable number of hours run in for NEBO 8.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

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