Onix Reference Speakers *PIC*

[hongrn]

http://i2.photobucket.com/albums/y48/hongrn/OnixRef3Graph.jpg


Can someone please take a look at this and explain to me this crossover topology? I haven't touched upon the 2.5 or 3.5 ways yet, so I have lots of questions on the subject, but I know Jeff B is working on a spreadsheet that could possibly incorporate the extra woofer. Anyway, this is the Onix Reference 3 from the av123.com site. The specs are as follows:

# System: 4-way rear-vented floorstanding loudspeaker
# Drivers: (2) Atohm 7", (1) Vifa XT Concentric Ring Radiator, (1) magnetostat super tweeter
# Crossover: 4th Order
# Crossover Points:
# Bottom woofer : 28 Hz - 150 Hz
# Upper woofer : 35 Hz – 2.5 kHz
# XT tweeter : 2.5kHz – 30 kHz
# Super TW: 15 kHz – 45 kHz
# Finish: Birds Eye Maple or Piano Black Lacquer
# Frequency Response: 28Hz - 50kHz (+/- 3dB)
# Impedance: 4 Ohm
# Efficiency: 90 dB (@ 1 Watt / 1 Meter)

Questions:

1. Isn't this a 3.5 way? If it is, please explain the cutoffs of both the bottom and mid woofers. Why the difference in the low end frequencies (28Hz vs 35Hz). Wouldn't you use the same woofers in such a system?

2. In a normal 2.5 way, let's say MMT, where do you usually cut off the bottom woofer (for example Fs to 100Hz)?

3. Does the mid woofer pick up where the bottom one left off, or does it start from Fs to 2.5KHz where it crosses with the tweeter? If you look at the Onix system, the woofers overlap in coverage. Is it how it's done?

4. If you modeled something like this, would the woofers have their own enclosure?

Let's hope we start a good discussion here. Thanks everyone for your help.

Hong

[chrisg]

> Can someone please take a look at this and
> explain to me this crossover topology? I
> haven't touched upon the 2.5 or 3.5 ways
> yet, so I have lots of questions on the
> subject, but I know Jeff B is working on a
> spreadsheet that could possibly incorporate
> the extra woofer. Anyway, this is the Onix
> Reference 3 from the av123.com site. The
> specs are as follows:

> # System: 4-way rear-vented floorstanding
> loudspeaker
> # Drivers: (2) Atohm 7", (1) Vifa XT
> Concentric Ring Radiator, (1) magnetostat
> super tweeter
> # Crossover: 4th Order
> # Crossover Points:
> # Bottom woofer : 28 Hz - 150 Hz
> # Upper woofer : 35 Hz – 2.5 kHz
> # XT tweeter : 2.5kHz – 30 kHz
> # Super TW: 15 kHz – 45 kHz
> # Finish: Birds Eye Maple or Piano Black
> Lacquer
> # Frequency Response: 28Hz - 50kHz (+/- 3dB)
> # Impedance: 4 Ohm
> # Efficiency: 90 dB (@ 1 Watt / 1 Meter)

> Questions:

> 1. Isn't this a 3.5 way? If it is, please
> explain the cutoffs of both the bottom and
> mid woofers. Why the difference in the low
> end frequencies (28Hz vs 35Hz). Wouldn't you
> use the same woofers in such a system?

> 2. In a normal 2.5 way, let's say MMT, where
> do you usually cut off the bottom woofer
> (for example Fs to 100Hz)?

> 3. Does the mid woofer pick up where the
> bottom one left off, or does it start from
> Fs to 2.5KHz where it crosses with the
> tweeter? If you look at the Onix system, the
> woofers overlap in coverage. Is it how it's
> done?

> 4. If you modeled something like this, would
> the woofers have their own enclosure?

> Let's hope we start a good discussion here.
> Thanks everyone for your help.

> Hong

It looks to me almost like it's more of a variation on a 2.5 way speaker. It seems like a 2 way with a .5 woofer on the bottom and a .5 supertweeter on the top end. I doubt they are actually bandpassing the XT25 at 30kHz making the supertweeter a .5 brought in a 15kHz. As far as the different woofer points go, I would bet the the upper one handling mid-range frequencies and down has a higher cutoff because it's in a seperate sealed enclosure whereas the bottom woofer is handling baffle step and maybe is loaded into a seperate ported enclosure. They could also be bandpassing the upper woofer with a 1st order electrical network to help out the system frequency response or just to prevent too much bass from muddying up the midrange - that would make it a 3 way with a supertweeter.

Anyway, I'm just taking a wild guess. You could always probe them for more details.

- Chris

[darrenk]

Hello Hong,

Without looking at the design in too much detail, I would say that I would call it a 2.5 way design. Probably running the lower woofer in its own ported enclosure, and the upper woofer in a sealed enclosure. Usually both woofers will have the same alignment, but I've done the mixed sealed/vented thing before and got pretty good results. It is typical in a 2.5 design that the upper woofer will play from the lowest frequencies all the way up to the crossover point with the tweeter. The lower woofer will play up to 300 or 400 Hz, and will essentially compensate for the baffle step rise. Both work together at the lowest frequencies for the maximum cone area and bass output.

As far as the super tweeter on top, they are probably just using it with a very high crossover point, and letting the XT tweeter run full range.

The woofers could either be in the same enclosure volume or not, it's kind of a designer's choice sort of thing. Probably most people would recommend to keep them separate though, I'm guessing.

Great questions!

Darren

> Can someone please take a look at this and
> explain to me this crossover topology? I
> haven't touched upon the 2.5 or 3.5 ways
> yet, so I have lots of questions on the
> subject, but I know Jeff B is working on a
> spreadsheet that could possibly incorporate
> the extra woofer. Anyway, this is the Onix
> Reference 3 from the av123.com site. The
> specs are as follows:

> # System: 4-way rear-vented floorstanding
> loudspeaker
> # Drivers: (2) Atohm 7", (1) Vifa XT
> Concentric Ring Radiator, (1) magnetostat
> super tweeter
> # Crossover: 4th Order
> # Crossover Points:
> # Bottom woofer : 28 Hz - 150 Hz
> # Upper woofer : 35 Hz – 2.5 kHz
> # XT tweeter : 2.5kHz – 30 kHz
> # Super TW: 15 kHz – 45 kHz
> # Finish: Birds Eye Maple or Piano Black
> Lacquer
> # Frequency Response: 28Hz - 50kHz (+/- 3dB)
> # Impedance: 4 Ohm
> # Efficiency: 90 dB (@ 1 Watt / 1 Meter)

> Questions:

> 1. Isn't this a 3.5 way? If it is, please
> explain the cutoffs of both the bottom and
> mid woofers. Why the difference in the low
> end frequencies (28Hz vs 35Hz). Wouldn't you
> use the same woofers in such a system?

> 2. In a normal 2.5 way, let's say MMT, where
> do you usually cut off the bottom woofer
> (for example Fs to 100Hz)?

> 3. Does the mid woofer pick up where the
> bottom one left off, or does it start from
> Fs to 2.5KHz where it crosses with the
> tweeter? If you look at the Onix system, the
> woofers overlap in coverage. Is it how it's
> done?

> 4. If you modeled something like this, would
> the woofers have their own enclosure?

> Let's hope we start a good discussion here.
> Thanks everyone for your help.

> Hong