help with modeling Beyma 10MW/ND

[Mike Arnopol]

Hey guys. I'm trying to come up with a lightweight alternative to my Wizzy 10. I was looking at the Beyma 10MW/ND. Looks pretty good on paper. A bit low spl, but a 7.5 mm xmax. It appears that from my not-so-good measurements the Wizzy is about .75 square feet with the port shelf of 11.5" x1.25" x 8".
I downloaded WinIsd pro but I'm having a tough time getting it to work. Also the program won't close. I have to shut my computer down.
I'd like to make a cab with similar dimensions but I'm trying to find out if the Beyma is a good choice. The Wizzy is pretty good, but it's really difficult (even with a parametric) to tame the mids. The Wizzy is a pretty decent compromise, but I think that I could do better. I know the Beyma is pricey, but as I plan on making a few foam core fiberglass enclosures this summer I think it would be worth it to shave a few pounds and have a better, higher power handling driver.

[MuzikMan]

If you are using Windows you might need to run WinIsd in Compatibility mode (Windows 98) to get it to shut down properly.

[rpsands]

Here is my batch script to kill winisd in win7--

Save a text file with this as "close winisd.bat' and put it on your desktop. Make sure it's actually saved as a batch file not a text document.

One line:
taskkill /f /im winisd.exe

[will33]

WinISD can be picky of some spec isn't dead on out to the nth degree. Oftentimes I'll input just a few specs to get it to accept the driver then open a new project with that driver then add/change the rest of the specs to match the manufacturers spec sheet.

[dhomer]

I have modeled both the 10MW/ND and the 10G40 for a 2-10 wedge I'm building for a customer. The optimum alignment would be under 1 cu.ft, but LF response will be practically nonexistent. Rolls off steeply on the high side of 100Hz. These CAN be made to work w/a larger box.

For a single driver try 2000cu.inches, and tune it to 53. The response graph will look a little odd, but we're looking for flatness between 60-100Hz. What will have to happen is you will need to boost the bass EQ about 2dB, but it should work

[DukeLeJeune]

In a .75 cubic foot box tuned to the lower 50's, I think the Beyma looks good for low-E tuning but not for low-B tuning. Tuned to 52 Hz, I get -2 dB at 81 Hz with no upper bass bumpage.

[rpsands]

It might be worth sneaking the tuning up to 60hz in a box that small, and using a steep HPF ahead of your signal (50hz 4th order BW or so). You're going to have so little output under 60hz anyway it's probably worthwhile.

I don't have a driver file for that woofer and am not interested in entering it right now, but I'd suggest exploring that (use the EQ/Filter tab to use a 4th order 50hz bw high pass).

[rpsands]

Got de-lazy and entered it...

Best results I got were .9cf, 60hz, 4th order 40hz bw. -3db @ 60.5hz or so (low B capable), 200 watts displacement limited.

* note regarding tuning: My experience has been through modeling that you can get your tuning frequency pretty high when you cram something in a tiny box. It was actually agedhorse from GB who clued me into that when I was modeling some ridiculously low QTS Eminence woofers that aren't really optimal for bass. The reason seems to be that small boxes drastically limit excursion. I really don't know all the math involved there, but it's interesting to play with.

Also note this isn't that useful if you don't have the facility to get a steep HPF ahead of your signal. These can be had pretty cheaply these days though. Putnam quotes around 200 bucks for a custom line/instrument level bw filter last time I talked to him. I'd imagine you could get one with 35hz/40hz/45hz settings or something like that (maybe even a variable one).

Without the HPF, you're displacement limited to around 100 watts @ 40hz...OK for 4-string. Downside is 50w @ 30hz, definitely unsuitable for 5-string.

[Arjank]

Did you guys use the ol' tsp's? (which have a low Qes)
Just see the results I simulated earlier in this thread Beyma 10MW/ND
The 10nw/nd is a great performer.

[rpsands]

I used the TSPs from the pdf on Beyma's site.

[Mike Arnopol]

I was looking at some old thread (forgot if it was here) from '07. On that they listed the QTS as .26 (which would suck). The current ones (that are consistent with US Speaker and Beyma's site) it's listed as .32 which in my limited experience is good for reflex enclosures for bass. There are lots of 10's (Faital and others) where everything is looking cool until I see the QTS's of .22 to .26.

[rpsands]

The model I used calculates the QTS as .317.

Low QTS is fine if you don't mind attenuated low end

[Mike Arnopol]

I've built lots of cabinets in the past and my experience with low QTS is that there is less "bloom" to the notes if that makes sense. Since attenuated low end is easily fixable with eq I found that the quality of the beginning and envelope to the notes was dryer and tighter (too tight) with low QTS drivers. In other words I could get a driver with a QTS of say .22 to sound (in terms of frequency response) similar to a driver with a QTS of say .32. ( I always have different parametrics around)But they FELT different. I'm not an engineer but I have very good ears. Isn't it true that a low qts speaker has essentially more damping? (bigger magnet, tighter surround) Is that why I perceived it as "too dry and tight"?

[rpsands]

I think you're getting into waterfall plot territory instead of FR territory--my understanding (although limited) is that speakers will not tend to affect that seriously unless they are going into distortion modes (e.g. exceeding xmax or getting close to it).

Not really sure though Need someone with a much bigger hat.