CSS Driver Idea

[planet10]

Originally posted by audiobomber
Price wasn't a consideration in my case, nor was efficiency.

Even so, i'd go with WR125 + tweeter. If i wanted more efficiency, i'd be looking at Fostex.

dave

[Timn8ter]

Originally posted by planet10


Some black 1354 phase plugs is on the top of your list (1 pr backordered)... speaking of phase plugs...Tim have you had a chance to try the 207?

dave

Looks like equal opportunity prodding. I'll be playing with them tonight although I'm a little blurry eyed following last nights Moby concert.

[Jim Griffin]

Let me comment on Planet 10/Dave's reply from above:

"The 2 drivers are in the same league (until you throw price into the equation) The CSS trades going lower for a relative lack of top end. It is a fair compromise. The CSS gives up a bit of efficiency to the Jordan -- in this case a consequnce of the XBL which means less distortion. Really the Jordan is challenged to get to 80 cycles... "

These two drivers are very similar in their bass ability according to my BassBox models. The JX92S has an Xmax of 4.5 mm vs. the WR125S value of 6 mm. When I model them in the same size 7 liters vented box their 3 dB down points compute to be within 2 Hz of each other (the WR125S being lower) while the 7 liters sealed boxes 3 dB down points are within 1 Hz on the low end (the JX92S being lower). Now the JX92S has slightly more cone area so it makes up for its smaller Xmax vs. the WR125S. I would call it a dead heat on their bass ability.

The primarily differences between these drivers relate to the JX92S's capability to produce about 3 dB more output in SPL. This difference also shows up at the SPL level achievable at their rated Xmax values. At 1000 Hz and with 1 watts input the JX92S has a sensitivity of 89 dB while the WR125S runs 86 dB. With a 30 watts level signal signal at 50 Hz the vented JX92S can produce more than a 97 dB SPL level while the WR125S runs about 3 dB lower in its SPL level under the same conditions.

The JX92S trumps the CSS driver on the high end of the band (15 to 20 kHz) if you were trying to run them full range.

I have measured data on the JX92S at:

http://www.creativesound.ca/pdf/JX92SG2siDesignPak.pdf

Note that for this JX92S design the 7 liters sealed box measures at a 3 dB down point of 70 Hz and a vented box 3 dB down point is 51 Hz based upon these near field measurements.

Bottom line is that the JX92S has slightly more sensitivity and a 3 dB more SPL output level than the WR125S. It is up to the user to decide whether these sensitivity differences, any sound quality difference, and higher cost of the JX92S vs. the WR125S would be justified.

Dave, I should say that the JX92S or the WR125S can produce more than enough bass output below 80 Hz for many users. In fact, in MLTL boxes for the JX92S (and likely for the WR125S) both speakers would likely move their 3 dB down points into the 40's Hz range. Both of these drivers are rather remarkable for their size and output. Now if you wish to achieve pressure wave bass levels, you'll have to use a subwoofer with either driver.

Jim

[audiobomber]

Can someone please tell me the correct volume for a sealed bipolar WR125S? I've used two calculators and they're giving me different answers (28 vs 52L).

I entered the specs in WinISD myself, so I may have made an error.

[Timn8ter]

The answer may depend on what your goal is. Do you have a specific F3 point in mind? The volume numbers you've posted produce nearly the same F3 point however the smaller box will give you a rise approaching 100Hz before it rolls off.

[Cal Weldon]

Originally posted by planet10
ApexJr 50 cent tweeter.

Uh Dave,

Those actually cost a whole dollar.
plus shipping
plus GST
plus exchange.

[audiobomber]

Originally posted by Timn8ter
The volume numbers you've posted produce nearly the same F3 point however the smaller box will give you a rise approaching 100Hz before it rolls off.

I don't get it. I used this calculator http://www.mhsoft.nl/spk_calc.asp#sealed
and WinISD and specified a Q of .707 for each. How the heck do they give such a different result?

I happen to have a pair of 50L cabs with no plan, so that interests me. I'd love to stretch f3 down to 60 Hz but OTOH I'd prefer a sealed box.

[Timn8ter]

I don't know what to tell you about the on-line calculator but I can say that the 50L sealed box should perform nicely and give you extension to 80Hz which still allows enough wiggle room to roll to a sub. Should work well.

[planet10]

100 litres, 50 litres, 10 litres, 0.25 cuft vented as on the spec sheet. (MacSpeakerz, factory specs)

50 & 100 are not much different Q less than 0.7

dave

[audiobomber]

Originally posted by planet10
It may be sacriledge, but in our 1st crack at this puppy, we are going to waveguide load the ApexJr 50 cent tweeter. If we decide that doesn't cut it we will upgrade to the Audax gold dome version.dave

I think you should use the Hi-Vi RT1L round planar tweeter. It would be too cool to have both a tweeter and a mid-woof with copper phase plugs. ;~)