• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

New 15" Scanspeak Ellipticor

andreasmaaan

Master Contributor
Forum Donor
Joined
Jun 19, 2018
Messages
6,652
Likes
9,399
When it comes to the most distortion-free reproduction of peak levels, one or the other PA chassis is the answer.
BMS 6S217
BMS 8S219 (used as BR, an 80Hz crossover should be possible)
I don't know independent HD measurements of these chassis. I have the BMS 6S217 here, but haven't measured it yet.

B&C also make some good ones for this type of purpose, e.g. 8MBX51.
 

egellings

Major Contributor
Joined
Feb 6, 2020
Messages
4,005
Likes
3,245
What's the rational for using an elliptical voice coil? What does it get you? How is it better than a round one?
 

mhardy6647

Grand Contributor
Joined
Dec 12, 2019
Messages
11,217
Likes
24,183
Were it smaller, I'd be oh-so-tempted to put an Ellipticor woofer in an old LRE "Eliptoflex" [sic] enclosure -- or am I being too... (wait for it)... elliptical? :cool:

1605916086631.png

source: https://worldradiohistory.com/Archive-Catalogs/Lafayette-Catalogs/Lafayette-1964-640.pdf
 

howard416

Active Member
Joined
Sep 12, 2019
Messages
246
Likes
143
I am surprised to see a driver in this mega price range uses a treated paper cone instead of some unobtanium material.

Presumably these guys know what they are doing.

Cheers
It's almost a shame that aluminum isn't used more often for home hi-fi woofers. Don't really see any advantages of paper over aluminum for that application (pro audio is obviously different).

Why I say the above is due to the following advantages of aluminum over paper:

- we typically see a significantly higher first breakup mode frequency with aluminum over paper, allowing for a wider fully-pistonic passband (for whomever that matters)
- aluminum almost never suffers from a surround edge resonance that, when present, tends to cause a narrow response dip somewhere between 600 Hz and 1100 Hz
- operating near (not even "into") the breakup range of paper cones often forces playback with elevated harmonics at the harmonic sub-frequencies that would be considered "natural" for that given size of woofer. An aluminum cone would generally present with lower harmonic distortion in the usable passband because of the increased frequency of the first breakup mode. Then again, you can cherry pick specific examples of paper cones with higher breakup frequencies and aluminum cones with lower breakup frequencies, which almost renders this whole point moot
 
Last edited:

briskly

Active Member
Joined
Jul 10, 2019
Messages
115
Likes
153
Lumped parameters are in the range of PA subwoofers. Generous overhang suggests high excursion performance for the category. This woofer faces a competitive market space.

Do you know what makes IMD? How does harmonic distortion relate to IMD? For example if we have a driver with higher 2nd HD and lower 3rd HD, how does the IMD compare to driver with lower 2nd HD and higher 3rd HD?
Having said that, the essential relationship as I understand it
Any model of nonlinear distortion that produces nonlinear harmonics will create intermodulations with additional tones. The simplest model is a polynomial series (a₁x + a₂x² + a₃x³...). The coefficient is the particular characteristic of the system, the term exponentiated is the input tone(s). For one tone, we have:
a₁(b*cosωt) + a₂(b*cosωt)² + a₃(b*cosωt)³...
a₁b(cosωt) + a₂b²(1+cos(2ωt))/2 + a₃b³(3cosωt+cos3ωt)/4...
You may notice the static offset associated with the even ordered term. Higher terms change more rapidly (per 10dB input change, 20 dB second order, 30 dB third order, and so on).
For two-tone inputs, second-order only:
a₂(b*cosω₁t + c*cosω₂t)²
a₂(b²(1 + cos2ω₁t)/2 + b*c(cos(ω₁t+ω₂t) + cos(ω₁t-ω₂t)) + c²(1 + cos2ω₂t)/2)
Filling in the other orders is a tedious exercise in trigonometric identities and the multinomial theorem. The mixed middle terms, representing intermodulation, are capable of presenting the sum and difference associated with periodic inputs.

What was meant was that the elliptical shape of the voice coil and dust cap is "asymmetrical" to the circular cone, surround and circularly arranged magnets.
The result should be (as I understand it) that distortions of odd order are suppressed, at the price of a more distortion of even order, as asymmetrical nonlinearity generates high even order distortions.
For example when the cone or dust cap breaks up into partial oscillations.
The geometric arrangement here does not directly relate to harmonic products but the linear frequency response. The goal is to decompose the VC former coupling to individually strong axially symmetric resonances into separate lesser resonances. This is not to make the driver behave more rigidly, which Scan-Speak has usually avoided in the past.
 
Last edited:

Samuel Gee

New Member
Joined
Oct 9, 2021
Messages
1
Likes
0
Nice woofer! I wonder if it would play in a car audio application. Can this woofer be in a infanet baffle??? I'm not to familiar with woofer specs
 

Jukka

Active Member
Joined
Apr 24, 2019
Messages
248
Likes
168
It comes with a trim ring to hide screw heads. Absolutely worth the price!
 

Ra1zel

Addicted to Fun and Learning
Joined
Jul 6, 2021
Messages
531
Likes
1,048
Location
Poland
I had pleasure recently to hear this 95dB efficient beast in person. Extremely impressive performance from mid bass to lower midrange, can play louder than almost anything, super clean and dynamic. However in a sealed box deep bass doesn't exist, use of subwoofers is necessary, which is kinda funny to think that you are going to cross 15 inch driver to subs.
 

Head_Unit

Major Contributor
Forum Donor
Joined
Aug 27, 2018
Messages
1,341
Likes
688
the Purifi passive radiator(s) is pretty much compulsory because it is very finicky about port design
Why is that? High excursion output? Making a big enough port in the small box of that reference design not workable?
If so, what about a larger box with a lower tuning? (Confession: after seeing 84 dB sensitivity, while I admired that design greatly I didn't investigate it in depth)
 
OP
Ilkless

Ilkless

Major Contributor
Forum Donor
Joined
Jan 26, 2019
Messages
1,757
Likes
3,438
Location
Singapore
Why is that? High excursion output? Making a big enough port in the small box of that reference design not workable?
If so, what about a larger box with a lower tuning? (Confession: after seeing 84 dB sensitivity, while I admired that design greatly I didn't investigate it in depth)

Dennis Murphy found problems with packaging (needing a large *and* long port) and/or port noise in a standmount format.
 
Top Bottom