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Old 11th January 2010, 10:40 AM   #1
MIKET is offline MIKET  United States
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Default NS10M substitute

I wanted to build my DIY replacement for the now obsolete Yamaha NS10M using some existing drivers from (P)eerless and (S)EAS, as a result I am calling these the PS10M. This is my first attempt on Paper, I do have the drivers in hand, so I hope to cut some wood in the next few weeks and get this project rolling.
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Old 11th January 2010, 11:06 PM   #2
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I can place them in a smaller sealed box and get a similar low to the original Yamahas. The original NS10M is in a much smaller cabinet. 15" x 8.5" x 7.75" and sealed, on the other hand my design is 11.5" x 16.25" x 8" and ported. The real question is.....Is it more important to be the same or better (more extended frequency response)?
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Old 12th January 2010, 02:12 AM   #3
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As this speaker appears to be a replacement for your old speakers, and not an attempt to replicate the speaker, I don't think the naming convention is a good one. What you have here is a new speaker, it shares nothing in common with the NS10M.

Now if you want to do something along the lines of a "clone", the very least you will want to do is a frequency response of the NS10M, and attempt to replicate that tonal character with your new speaker.

The crossover needs some work. There are a lot of things to consider when designing a crossover, a lot. At the very least, the tweeter is a couple dB more sensitive than the woofer, before any BSC, and you have no attenuation pad. I would recommend some more research before embarking on your own design.

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Originally Posted by MIKET
Is it more important to be the same or better?
That is a question that only you can answer.
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Old 12th January 2010, 11:16 PM   #4
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Default Crossover Design

DcibeL,
After reading your reply I went to Jay_WJ homepage - Jay's speaker building pages and did some reading. I'll saw the Designing Crossovers with Software Only section and he suggests initial design of the crossover using Speaker Workshop or Passive Crossover Designer. I downloaded both. As for the enclosure size, I think the smaller enclosure will be a better choice for what I want to build. (an NS10M replacement for nearfield mixing)
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Old 13th January 2010, 12:19 AM   #5
DcibeL is offline DcibeL  Canada
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Jay's "crossover design with software only" page is a good one, read through it thoroughly. You may also want to look here:

FRD Consortium tools guide
FRD Consortium

The FRD tools are not very user friendly, so be sure to read the documentation thoroughly to make sure you are doing everything right.
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Old 13th January 2010, 01:43 AM   #6
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Default Simulation

Ran Passive Crossover Designer and the selected values don't look bad on paper.
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Old 13th January 2010, 10:46 PM   #7
DcibeL is offline DcibeL  Canada
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Well I guess you're done, great success!

Seriously though, I hope you take my "reasearch" comment to heart. There is a lot more to crossover design that what you have presented above. I am assuming that the graph you made above is just traced response from the datasheet, and applied the crossover values you've chosen.

What you'll end up with is a speaker that "works", but far from as good as it could be. Some general steps to use when looking at speaker design:

-trace response of drivers from datasheet or 3rd party mesurement. Make note of how this frequency response was generated, IEC baffle, free air, infinite baffle, etc, as this will influence the graph.
-trace impedance
-model bass driver on measurement baffle, as well as desired cabinet. save response (Unibox).
-model baffle diffraction using BDS (FRD tools) of your divers on the desired baffle. Save response.
-Combine response using FRC. Use FRC to extract minimum phase for the acoustic response and the electrical response (impedance). Save response. This will be your simulated response of the driver in the cabinet you designed for it.
-import resulting response to the Passive Crossover designer and start crossover design.
-take into account resulting electrical impedance and phase, this will tell you how easy the "load" is on your amp.
-take into account individual driver acoustic phase and power response. Enter driver offsets for accurate simulation (read documentation, the numbers entered here are weird)
-model frequency response on and off axis, off axis is just as important to know where the nulls occur among other things

This is just a basic run down, off the top of my head. For more detail, follow Jay's page as well as the pages I linked to above. Hopefully from that you can see why many people choose existing "proven" designs as first projects, rather than trying to spin their own. It appears clear to me that most people prefer to DIY build a speaker that works very well ie "proven" design, then have something they can say "I designed that" but doesn't work quite as well.
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Old 14th January 2010, 11:10 AM   #8
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Default Crossover Tweaking

Still tweaking the crossover values with Passive Crossover Designer, here is the best result I've gotten with software so far.
FRD and ZMA files from Driver FRD & ZMA files
I used the 850439 FRD and ZMA files since it is very close to the 830875 in many respects.
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File Type: jpg tweeked crossover.jpg (39.5 KB, 265 views)
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Old 14th January 2010, 07:49 PM   #9
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Those are traces from the manufacturer's data, as it says on the page. That would be the first two points in my post above, you still need to do points 3,4,5 to get something useful for crossover simulation. A frequency response without phase data is useless for crossover design.

I'm afraid I can't help you any more. Good luck with your project.
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Old 16th January 2010, 12:23 AM   #10
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Still working on tweaking the box size for best transient response while still keeping the box size reasonable. 12.5 liter tuned to 44 Hz, 7.38" x 10.67" x 15.67". with 3-1" ports 6.56" long this should yield an F3 of 58Hz.
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