Require help with designing crossover to use with Paradigm Studio 100 v4 drivers

[Johnnz]

Hi again all!
I built a pair of Nat P's a couple years ago which I am still using and very happy with but speaker building must be a bug and I could not resist the chance to design and build some new speaker cabinets to house some Paradigm drivers I won at auction for cheap!

Link to auction listing here: http://www.trademe.co.nz/Browse/List...x?id=675893761

They are Studio 100 v4 drivers. Usually there are 3 bass drivers in the Studio 100 floorstanding speakers but the auction I won only contained one pair of base drivers. Anyhow, I figured I could make a cheap and cheerful pair of 3 way floorstanders with them anyway and have fun with some more interestingly angled cabinets - see my last project here http://www.htguide.com/forum/showthr...r-Nat-P!/page3

Cabinet making I am capable of but crossover design not so much unfortunately. I am having trouble finding any specifications on the above drivers too so things are looking a bit grim when it comes to finding a way to design a suitable crossover.

Is there any one that can suggest resources or schematics that would work with these drivers? Thanks!

[Johnnz]

I found this information on Paradigm website about the crossovers originally used:

2nd-order electro-acoustic at 2.0 kHz, 2nd-order
electro-acoustic at 500 Hz (lower bass drivers)

Does that help or is there a lot more information required still?

[cjd]

We'd need measurements of the drivers in cabinet, or at least infinite baffle to which we could attempt to manually apply calculated baffle step, etc. and guess at offsets.

[Johnnz]

Thanks for the reply. What equipment would be required at a minimum to take measurements of the drivers? Is there a link to a site that explains how to go about gathering such data?

[agrippa]

DO you have any speaker/parts/audio stores in New Zealand? You might be able to get them to test them for you if they have the ability...some do. Another option would be to mail some of them to an experienced/respected tester. Shipping costs would suck but it might be cheaper than doing it yourself...However, if you do it yourself you would have equipment for other projects.

[Johnnz]

DO you have any speaker/parts/audio stores in New Zealand? You might be able to get them to test them for you if they have the ability...some do. Another option would be to mail some of them to an experienced/respected tester. Shipping costs would suck but it might be cheaper than doing it yourself...However, if you do it yourself you would have equipment for other projects.

Hi there, I managed to find a company that can do speaker testing. Before I talk to them could you please tell me what driver parameters are required for a crossover to be designed? Once I get this data is there software available to help design the needed crossover or an online guide that I could follow? (Bearing in mind that this will be a 3 way design). Or are there people on this forum that could draw out the required circuit? How much would that cost?

Thanks.

[JonMarsh]

You meed frequency response curves, preferably in FRD text format, and impedance curves, in a text file format like ZMA, measured in the cabinet. One also needs information about the relative driver offset - that is, the acoustical offset in the plane from the front baffle. this can be estimated, but I usually prefer to do measurements such that they are made with a microphone at the same point, with the same window setup/delay, so that the woofer delay can be accounted for, OR I have to determine the approximate acoustical offset and use that in a program like LSPACD for designing the crossover network.

Go to the IJDATA site, where LSPACD comes from, and you can download a presentation about LspCAD describing how it works, and even download the manual- this will give you insight into how all crossover design programs work, but it doesn't teach you the technicalities about speaker design.

My best guess might be that the original paradigm design might have used multiple drivers and done part of the BSC compensation rolling off the extra woofers lower down. that's just a guess. If they had 3 woofers normally in this model, I'd guess they're 12 ohm at least, as three 8 ohm drivers would be too low an impedance. Using a single 12 ohm driver will have somewhat low sensitivity, which means you may need more voltage to drive a system with a single one for the same SPL.

http://www.ijdata.com/index.html