What is the X-over frequency ? Also how did you get rid of the large peak starting at 800hz ? See pdf > https://www.madisound.com/store/manuals/scanspeak/15w_8530k00e.pdf
2.3kHz, 12dB electrical. Likely between 12 and 18dB acoustic.
You mean this peak?
(Measured on listening axis)
I didn't deal with it, but may in the not-so-distant future. It really isn't that annoying.
Z plot:
I could use a non-zobel CR-shunt filter to flatten that out a bit, or a full LCR shunt-notch.
Troels used it here, and the notch should apply:
Ellam-XT
An externally hosted image should be here but it was not working when we last tested it.
3mH/18.2uF/8.2 ohms
The difference would be the magnitude of cut with the resistor, depending on the rest of the design. The LC components can be altered to get the same effect with less copper too.
Later,
Wolf
That's taken care of in the rolloff of the xover. You see the system FR does not have that in my plot above.
The reason it's okay for the 8530 is that it's a super-clean HD driver, and easily remedied. The 8137A has more HD as freq increases, and is an 8" driver. 8" drivers are pretty much limited to 1.8kHz tops, or they beam in the mids.
Later,
Wolf
The reason it's okay for the 8530 is that it's a super-clean HD driver, and easily remedied. The 8137A has more HD as freq increases, and is an 8" driver. 8" drivers are pretty much limited to 1.8kHz tops, or they beam in the mids.
Later,
Wolf
Not the same driver but a 18W8531 which has a similar bump at the roll off. As mentioned by wolf_teeth, it's handled by the crossover.
In the FR below, it's a AR series xo and look at the LH graph. The dark blue line is the raw driver and blue is after the filter is applied. Final shaping is done via the zobel cap which also helps with phase to get a deep reverse null. The RH graph just shows the completed speaker with both drivers.
I found it impossible to use this woofer in a standard series xo but easily managed in the AR series.
Attachments
I'm not familiar with the Usher driver so can't comment. Crossing over below 1500Hz is going to require a very strong tweeter if used in an AR series xo.
FWIW, I've added the crossover for the 810921 + 18W8531G00 for reference. Note that this xo was used with a 8" 0.5 woofer so there is no BSC. It would need changes for a 2-way with BSC.
L1=0.1mH (0R05)
R1=5R6 (10W)
C1=20uF
C=3uF
R=5R6 (10W)
L2=1.2mH (0R19)
Czz=8.2uF
Rzz=8R2 (10W)
For a 2-way these changes would need to be made (approx):
R1=6R8 (10W)
L2=1.5mH-1.7mH (0R25) depending on BSC required (larger mH = more BSC)
Czz=6.8uF-5.6uF (i.e. smaller cap with larger inductor)
Rzz=6R8 (10W)
FWIW, I've added the crossover for the 810921 + 18W8531G00 for reference. Note that this xo was used with a 8" 0.5 woofer so there is no BSC. It would need changes for a 2-way with BSC.
L1=0.1mH (0R05)
R1=5R6 (10W)
C1=20uF
C=3uF
R=5R6 (10W)
L2=1.2mH (0R19)
Czz=8.2uF
Rzz=8R2 (10W)
For a 2-way these changes would need to be made (approx):
R1=6R8 (10W)
L2=1.5mH-1.7mH (0R25) depending on BSC required (larger mH = more BSC)
Czz=6.8uF-5.6uF (i.e. smaller cap with larger inductor)
Rzz=6R8 (10W)
Attachments
Here is the manufacture's Data > http://www.parts-express.com/pdf/296-616.pdf And here is a pic > Also here is the measured response graphs > http://www.parts-express.com/pdf/296-616g.pdf
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It looks like you went 2nd order (cap) on the tweeter with an added trap circuit around it. where you concerned about the Vifa surviving 1st order?
carlspeak
Yes I was. Xover being about 2.3kHz, 12dB is about the lowest I would go to prevent HD from coming in. The LCR is to tame the undamped Fs the XT25TG30 has. The resultant measured notch makes the impedance of the XT25 to be +/- 0.5 ohms over the entire audio band. Without killing the Fs, it can sound very nasal, and James Taylor sounds horrid without the notch.
Later,
Wolf
Personally I wouldn't use it in a AR series xo as the cone breakup is very high and hard for this type of crossover to deal with (more a job for higher order parallel crossovers). Usually for series you look for smooth roll offs (including bumps) and that generally means paper or polypropylene cones.
That is what everyone has told me, best for 3-way ect... What do you think of this driver when using a series X-over ? From the pic is that what they call a under-hung voice coil ? Link > Aurum cantus
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You really need to read a book.....
Likely yes on the first point, to keep enough flux concentrated on the gap.
Not necessarily on the second point. That depends on the sensitivity.
Later,
Wolf
Let me rework the question. If having 2 drivers of equal spl and size, 1 being under-hung and the other being over-hung ! Because of increased flux in the ones magnet assembly would that driver require more power operate ? Example I once built a kit comprised of a Dynaudio 17WLQ 4 ohm and a D260 tweeter. That speaker had a simple 6db X-over, and sounded great ! The only problem it liked power in excess of 100+ watts being power hungry ect... I wish I still had them, oh well ! The kit was designed by Madisound.
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