Cases for NS1000 Cross-Overs

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reffc
Posts: 94
Joined: Thu Aug 30, 2018 8:40 pm

Re: Cases for NS1000 Cross-Overs

Post by reffc » Fri Mar 08, 2019 8:12 pm

sq225917 wrote:
Fri Mar 08, 2019 12:58 pm
I'd clean those pots. ;-)

To be fair I've not checked anything beyond the raw FR with measurement. I made 3 iterations of the XO and ended up going for the one with the smoothest handover.

RT60, at HF? I don't live in a glass palace mate, it's a small well damped room. No one's worrying about RT60 at HF in a domestic setting
That maybe true but the context was that it's a factor for consideration along with furnishings that explains why in the real world, room measurements often result in falling FR compared with anechoic. Linkwitz wrote an excellent series of articles on room measurement which explains far better and in more detail than I'm able, or inclined to! :lol:

When using in-room measurements, forgetting this often results in people misguidedly using measurement to achieve a nominally "flat" setting which in truth is actually skewed well upwards when compared anechoically. The easy way to tell is close field measurement (ie within mm of the driver) to eliminate as far as possible other effects including reflections and absorption. It's not really relevant for 2/3ds of the midband or the bass but it is for the HF when designing a crossover.

I like to qualify statements as IME of forums, not doing that usually results in someone coming out of the woodwork to throw stones (not here of course) so it's a habit that's stuck, although I don't bother with forums these days due to the amount of trolling and smart alecs (not to mention the owner of one specific forum (again, not this one!) who I won't name and shame....he makes a good job of shooting himself in the foot himself but he's one of the reasons I couldn't generally be bothered with them these days). Maybe as I'm in friendlier company here, I can dispense with the qualifications.

karma67
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Re: Cases for NS1000 Cross-Overs

Post by karma67 » Fri Mar 08, 2019 8:43 pm

hi paul,i have the option of 4 and 8ohms on my kt88 amp,could you explain the difference please and what effect it has on the ns1000's.
ive just quickly tried it and to my ears on 4 ohms it seems to beef the bass up with a little loss in top end detail.

reffc
Posts: 94
Joined: Thu Aug 30, 2018 8:40 pm

Re: Cases for NS1000 Cross-Overs

Post by reffc » Fri Mar 08, 2019 10:08 pm

That's exactly what I'd expect. 4 Ohm tap will give a little more grip in the lower frequencies for impedances at say just under 6 Ohms or less. The 4 Ohm tap has a slightly greater damping factor and slightly lower distortion at the expense of slightly lower output for rising speaker load (impedances) when considered for 4 to 6 Ohm impedance loads. I think I have this right but Simon knows more about amplifier circuits and can correct me if this is not correct

sq225917
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Re: Cases for NS1000 Cross-Overs

Post by sq225917 » Sat Mar 09, 2019 2:25 pm

Valve amps, pffff, you're on your own. ;-~)

I'd suspect it's a combo of actual HF reduction and how that extra bass makes you perceive the treble. I bet a quick measure would show it to be within a fraction of a db at the top.
One more Paradise left to complete.

ChrisOH1
Posts: 147
Joined: Tue Jan 02, 2018 9:58 am

Re: Cases for NS1000 Cross-Overs

Post by ChrisOH1 » Mon Mar 11, 2019 12:37 pm

Hi Paul
It’s a process that I do not understand but am of course fascinated with at the same time and I can’t wait to hear how the new cross-overs affect the sound of the NS’s. Its reassuring to hear that the measurement of the Mid and HF support the settings that I was running the pots at anyway. Reassuring as of course if the pots are done away with so is the utility of being able to refine the performance in room.

They are now facing a serious challenge though as I have reinstalled my RMS (Avondale) Revelation II speakers and they are blowing me away. The tweeter is a Focal TC120, (inverted dome Titanium) and the mid-base are Monacor SPH-135C which are carbon-fibre cones. The drivers are all replacements as the originals all blew (at the same time) after I’d had the speakers for 10 years or so. This means that the cross-over which was designed for different versions of the drivers that are in there now but, blimey they sound good with my Studio III filling in the base. I already know I’m going to have to get them measured and the cross-over looked at to see how much potential is left in these things, they are that good, albeit a different experience to the NS’s. Very glad I kept them.

Look forward to hearing more on the progress with the NS’s, they’re in for a bake off now when they get settled in back here in Wales.

Regards

Chris
Last edited by ChrisOH1 on Mon Mar 11, 2019 3:47 pm, edited 1 time in total.

reffc
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Re: Cases for NS1000 Cross-Overs

Post by reffc » Mon Mar 11, 2019 3:12 pm

Good stuff Chris.

I made progress today with dis-assembly of one speaker, removal of all drive units, horrible fibreglass stuffing, wiring, switches and crossovers.

I've made up a new rear binding post panel which has been ash veneered and rebated for a perfect fit. I just have that to spray satin black and lacquer. Once done, I can re-assemble, rewire and test each drive unit before building a model in sim to test and tweak the crossover. Once that's done, and a few final alterations are made, we're good to go.

ChrisOH1
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Re: Cases for NS1000 Cross-Overs

Post by ChrisOH1 » Mon Mar 11, 2019 3:26 pm

You're motoring now Paul. You can see what i was talking about in terms of the speaker location below ie some diffusion built in and light from the window at first reflection.

System is as you can see in a different sate of repair to yours but, its a work in progress.

Image

The speaker enclosures are metal and the stand it integral, ported out of the bottom of the leg. External cross-overs on top of the monoblock to the right of the speaker.

YNWaN
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Re: Cases for NS1000 Cross-Overs

Post by YNWaN » Mon Mar 11, 2019 4:40 pm

Avondale turntable shelf too :) (you don't see many of them).
Mark

ChrisOH1
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Re: Cases for NS1000 Cross-Overs

Post by ChrisOH1 » Mon Mar 11, 2019 5:15 pm

I know, I call the photo "spot the Avondale". The shelf was too rich for my blood back in the day but, i had to have it when it came up on PFM. Fabulous bit of kit as always.

MTPapaDan
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Re: Cases for NS1000 Cross-Overs

Post by MTPapaDan » Mon Mar 11, 2019 10:11 pm

sq225917 wrote:
Fri Mar 08, 2019 12:58 pm
I'd clean those pots. ;-)

To be fair I've not checked anything beyond the raw FR with measurement. I made 3 iterations of the XO and ended up going for the one with the smoothest handover.

RT60, at HF? I don't live in a glass palace mate, it's a small well damped room. No one's worrying about RT60 at HF in a domestic setting
How would one go about cleaning those "tone controls" correctly? Hose them down with circuit cleaner while turning them full range? I ask because mine seem a bit "scratchy". When "tuning" them I discovered a couple of dead spots in each control in each speaker? Probably were set there by previous owner. Perhaps I should just remove them like Mark did? I'll have to find where he explained how to choose values for the "new" circuit.

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