NOS betsyk's

[GM]

Works for me!

I use 1" acoustic fiberglass, but if you're satisfied with the foam's performance, then use it.

GM

[fastbike1]

It's not modeled for any TL effects (a bit short perhaps). Driver is on the vertical CL and is centered perhaps 8 to 10 inches from the top. It's a wide baffle, shallow depth design similar to the Poor Man's Stradivarius.
I like the port to be about 6 inch from the bottom, but shouldn't be too critical. Straight BR.

I again emphasize that this is based on measured parameters from my 2010 dated BetsyK's. They were run in for about 24 hours before the final measurements.

Originally Posted by opa1

On the 61 l, what is the driver and port placement? Any offset of driver?

[opa1]

I have the green 2009 and 2012 set. I dont know how much they differ, if any.

Your Br would work good too. Might try them next.

I really dont want to use stands. The towers have the 36" Zd where I need it. Plus they dont take up much room.

Thanks,
Mark

[fastbike1]

My 2010 are greenish as well. You can always build the box a bit taller and put a false bottom in. I often either mount a crossover in the bottom or add ballast.

Here are the average measurements after 24 hours of break in:
Re = 5.8079 ohms
Fs = 49.8064 Hz
Zmax = 35.7954 ohms
Qes = 0.5695
Qms = 2.9404
Qts = 0.4771
Le = 0.4154 mH (at 1 kHz)
Diam = 168.2750 mm ( 6.6250 in )
Sd =22239.7074 mm^2( 34.4716 in^2)
Vas = 66.5831 L ( 2.3514 ft^3)
BL = 5.8642 N/A
Mms = 10.7753 g
Cms = 947.6355 uM/N
Kms = 1055.2581 N/M
Rms = 1.1468 R mechanical
Efficiency = 1.3573 %
Sensitivity= 93.3448 dB @1W/1m
Sensitivity= 94.7355 dB @2.83Vrms/1m
Krm = 1.089E-03 ohms Freq dependent resistance
Erm = 804.593E-03 Rem=Krm*(2*pi*f)^Erm
Kxm = 15.047E-03 Henries Freq dependent reactance
Exm = 609.473E-03 Xem=Kxm*(2*pi*f)^Exm

BTW, while I haven't put them in a box yet, they do sound pretty appealing just sitting in free air.

Originally Posted by opa1

I have the green 2009 and 2012 set. I dont know how much they differ, if any.

Your Br would work good too. Might try them next.

I really dont want to use stands. The towers have the 36" Zd where I need it. Plus they dont take up much room.

Thanks,
Mark

[GM]

Thanks!

FWIW, placing the driver at MJK’s [L*0.349] works well enough and vents tend to work best overall at around [L*0.8].

Plugging your numbers into the MLTLs I’ve posted show barely discernible differences in a sim, so are good to go as is, though of course some vent tuning is often required to get the best overall in room response same as any vented alignment.

GM

[opa1]

'I often either mount a crossover in the bottom or add ballast.'
Thats a good idea. I going to add a larger base on the tower for better footing. I could add ballast too.

Thanks for the measurements.

Mark

[fastbike1]

Good to know. Thanks for the info / ROT. I confess that I've paid for Martin's
worksheets several years ago but haven't spent any time really looking into them. Even have Mathcad.

Originally Posted by GM

Thanks!

FWIW, placing the driver at MJK’s [L*0.349] works well enough and vents tend to work best overall at around [L*0.8].

Plugging your numbers into the MLTLs I’ve posted show barely discernible differences in a sim, so are good to go as is, though of course some vent tuning is often required to get the best overall in room response same as any vented alignment.

GM

[opa1]

Going to get materials tomorrow. I'm painting them black so I'll be using mdf. I should have a flatpac by afternoon.

[GM]

Originally Posted by fastbike1

Thanks for the info / ROT.

You're welcome! BTW, what 'fast bike' do you ride?

GM

[fastbike1]

Currently a 2008 Triumph Tiger. 2003 Ducati Monster before that. I got the nickname in '95 when I would occasionally ride with a local Harley Owners Group. Had a 95 Ducati Monster then. First ride with the group, we were merging onto the interstate and I hit it to get up to speed. Unbeknown to me, behind me was a guy w/ a rep for a fast Harley and he was way way behind. After that, the group took to calling me Fastbike. Worked for me.

46 years of riding this year.

Originally Posted by GM

You're welcome! BTW, what 'fast bike' do you ride?

GM