Excursion in WinISD pro vs Xmax & Xmech

[Kev06]

Thanks for the thoughts, I was beginning to wonder if this was a bad idea but it sounds like these 10" drivers will probably be up to it then

Yes its the same driver from post #7; I was recommended this in another couple of threads - due to its low distortion it supposedly makes a good woofer as well as a sub.. so I'm trying to make it do both. I'm probably going to be using active crossovers for this one; I think I'd find it easier to match SPLs ..

Cheers
Kev

 

[Inductor]

Yes its the same driver from post #7;

I don't want to be too stingy but correct your data entered in the specs.

 

[chris661]

Thanks again Chris, a useful sanity check!

Maybe I should consider going for this with a bit more intent; the 10" L26 ROY seemed enough for my modest needs, but perhaps theres a case for going larger..

Cheers
kev

There's always a case for going larger. You have to tell when you've got enough for 99% of situations, and ensure it'll cope well enough with the 1% that it doesn't trouble you.

IMO, one of those 10"s per side will be plenty enough for most UK situations. If there's a party of some kind, throw a 35Hz high-pass in there and don't worry about it - they'll have some serious output available in the 40Hz+ range.

Chris

 

[Kev06]

Thanks Chris, thats a cunning plan. The excursion limits are caused by my intention to use the Linkwitz Transform - if I bypassed that physically or with a higher cutoff filter I'd be able to get much higher SPLs for parties etc.

Maybe I could even take it a step further and for HT use cut in an 80hz crossover to a separate subwoofer (with bigger drivers that deliver more umph for the money) - I'd be much more interested in impact than fidelity for explosions etc..

EDIT: Or I could just double-up the L26ROY's and have the best of both worlds.. but at a price.

Thanks for the idea!
Kev

 

[Kev06]

I don't want to be too stingy but correct your data entered in the specs.

Ah, have I messed up somewhere? Its very possible.

I know Le is missing - its not mentioned in WinISD's data entry procedure, and I've also seen it said to leave it out as WinISD doesn't use it well for the response curves. But is that incorrect and/or is there something else that I've got wrong?

Thanks
Kev

 

[Inductor]

Ah, have I messed up somewhere? Its very possible.

I know Le is missing - its not mentioned in WinISD's data entry procedure, and I've also seen it said to leave it out as WinISD doesn't use it well for the response curves. But is that incorrect and/or is there something else that I've got wrong?

Thanks
Kev

If you are using the same woofer for calculations (Seas L26ROY 10" Subwoofer - D1001-04) correct Le, Vas, Qes (Qts) from post #7.

Le = 0.53 mH (you have _)
Vas = 87 Litres (you have 93.46L)
Qes = 0.33 (you have 0.311)
Qts = 0.31 (you have 0.29), results from Qms/Qes.
D1001-04 L26ROY

 

[Kev06]

Oh I see. Unless I'm misunderstanding how it works, its not possible to just change those in the Pro version of WinISD; it calculates some of the values as you enter the perameters to ensure they all hang together- if you then change them breaking the mathematical relationship between the parameters, then it won't let you save. I guess its the difference between individually measured values on the spec sheets and what mathematically works out together.

TBH they all seemed pretty close, enough that I'd thought it wouldn't matter either way compared to the difference between a generic model spec and the actual driver I'd buy, which I understand can be fairly different.

Have I not understood this?

Cheers
kev

 

[Zero D]

@ Kev06

Here's a tutorial i wrote which "should" help in understanding the Data Input relationships etc in WinISD

http://www.diyaudio.com/forums/subwoofers/148729-how-correctly-use-winisd.html

 

[Kev06]

Thanks - thats really helpful; I've simply been using the order that WinISD itself specifies in the help file, I'd not considered there may be better ways. I'll have a go with yours and see how it works out.

Cheers
Kev

 

[Kev06]

I've re-entered the parameters in your suggested order and it has been accepted by WinISD pro

As before, those parameters that I enter manually agree (of course) with the spec sheet I'm working from, and those that are calculated are slightly different. So the entry order has changed which agree and which 'slightly' deviate, rather than making them all agree exactly. Its closer to what inductor wanted now, though Qts is still a calculated result so of course doesn't match exactly.

Reassuringly, I can barely see any difference in the results graphs (a line thickness or so here and there at most) so my plans aren't now all meaningless. Interestingly though, in my simulation there is almost a 10% increase in the box volume needed to get the same Qtc, which I'd say was significant.

So if this is a more correct way to do it then I'll use it in future.

Thanks again
Kev

 

[OscarS]

The most correct way is to measure the actual speakers for the T/S parameters.

 

[Kev06]

I can see how that would make the values less generic to the model and more specific to the driver, but I don't think it would help WinISD pro to accept them.

This is a change over the older version, where I could input any value - measured or otherwise. If I understand correctly, unless the parameters 'exactly' match its mathematical expectations (which my real-world measurements are deeply unlikely to do), the pro version says no. You have to input only some and let it calculate others to ensure they match as it expects.

Cheers
kev

 

[Zero D]

@ Kev06

Great, glad it worked out for you

I found that even with the previous versions, entering as i suggested always worked best