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  • jimbones
    replied
    Originally posted by hex168 View Post
    A two-way with the Fountek and an 8" or 7" will be problematic in terms of directivity. For near-field use it should be OK since less of the sound at the listening position will be from reflections. The issue with directivity is that the reflected sound will have very uneven frequency response and will influence the overall tonality.

    Here is a well-executed three-way with a ribbon. Take a look at the horizontal polars:
    https://www.erinsaudiocorner.com/lou...lharmonic_bmr/

    Here is a ribbon two-way with a small enough woofer for smooth directivity (ignore the frequency response issues caused by port or cabinet resonances). Again, look at the horizontal beamwidth:
    https://www.audiosciencereview.com/f...-review.17181/

    Since I can't find measurements for an 8" two-way with a ribbon, here's an 8" / 1" dome two-way that displays the problem I anticipate. See the horizontal contour plot, and the way it narrows as the woofer starts to beam and flares out when the tweeter comes in:
    https://www.audiosciencereview.com/f...-review.11108/

    Advice? Listen near-field, or add a midrange.
    Thank you Hex!!

    Leave a comment:


  • Paul K.
    replied
    My RS duets build used an RS225-8 with an RS28F-4 dome tweeter. The crossover was designed by Mark Krawiec since the duets were based on one of his designs. In order to minimize "nasties" from the RS225's metal cone as well as allow the tweeter to play low, Mark used a notched, Cauer-Elliptic quasi-8th-order crossover at 1400 Hz (the crossover is complex but it sure did the job). It would be interesting to hear from Alta on how they managed it and get some details about their crossover design.
    Paul

    Originally posted by jimbones View Post

    I would agree with that however how does Alta Audio do it? Their speakers sound very good...
    I agree that the theory does not support a large midbass and ribbon. ok so does that mean I go 3 way 8 inch, 3 inch and ribbon? or 8 inch larger soft dome tweeter and XO high for the ribbon?

    Leave a comment:


  • jimbones
    replied
    Originally posted by fpitas View Post
    Have to agree with hex168. A ribbon with a 7" or 8" woofer is an awkward design. Maybe use a much smaller woofer and add a subwoofer?
    I would agree with that however how does Alta Audio do it? Their speakers sound very good...
    I agree that the theory does not support a large midbass and ribbon. ok so does that mean I go 3 way 8 inch, 3 inch and ribbon? or 8 inch larger soft dome tweeter and XO high for the ribbon?

    Leave a comment:


  • fpitas
    replied
    Have to agree with hex168. A ribbon with a 7" or 8" woofer is an awkward design. Maybe use a much smaller woofer and add a subwoofer?

    Leave a comment:


  • hex168
    replied
    A two-way with the Fountek and an 8" or 7" will be problematic in terms of directivity. For near-field use it should be OK since less of the sound at the listening position will be from reflections. The issue with directivity is that the reflected sound will have very uneven frequency response and will influence the overall tonality.

    Here is a well-executed three-way with a ribbon. Take a look at the horizontal polars:
    https://www.erinsaudiocorner.com/lou...lharmonic_bmr/

    Here is a ribbon two-way with a small enough woofer for smooth directivity (ignore the frequency response issues caused by port or cabinet resonances). Again, look at the horizontal beamwidth:
    https://www.audiosciencereview.com/f...-review.17181/

    Since I can't find measurements for an 8" two-way with a ribbon, here's an 8" / 1" dome two-way that displays the problem I anticipate. See the horizontal contour plot, and the way it narrows as the woofer starts to beam and flares out when the tweeter comes in:
    https://www.audiosciencereview.com/f...-review.11108/

    Advice? Listen near-field, or add a midrange.

    Leave a comment:


  • jimbones
    replied
    Originally posted by jhollander View Post

    8th order 1/48
    Lol OK Lol. Steeeeeeepppppp

    Leave a comment:


  • Kornbread
    replied
    Originally posted by jhollander View Post

    8th order 1/48
    Steep.

    Leave a comment:


  • jhollander
    replied
    Originally posted by Kornbread View Post

    How steep?
    8th order 1/48

    Leave a comment:


  • Kornbread
    replied
    Originally posted by jimbones View Post
    Update: After checking, I plan on using a lower XO point, say somewhere between 2750 and 3000 and use a 7 inch driver, thinking that would be a better strategy. So an RS180P or SB17CAC35 and Fountek Neo 3.
    Don't get stuck on the sb17cac, sb has some good $/performance drivers. Just though that might be a good woofer to mate with a ribbon. IIRC, Wolf or pwryde used the cac in a project and it got good reviews.

    Leave a comment:


  • Kornbread
    replied
    Originally posted by jhollander View Post
    I used the RS180P to 3.6K and thought it was good.
    How steep?

    Leave a comment:


  • jimbones
    replied
    Update: After checking, I plan on using a lower XO point, say somewhere between 2750 and 3000 and use a 7 inch driver, thinking that would be a better strategy. So an RS180P or SB17CAC35 and Fountek Neo 3.

    Leave a comment:


  • jhollander
    replied
    I used the RS180P to 3.6K and thought it was good.

    Leave a comment:


  • donradick
    replied
    Originally posted by Kornbread View Post
    The P looks to be a little smoother from ~1-4k without quite the ringing? from +6k, although, the P does begin a rise at ~4k. Some of the SS can get quite $ expensive. Hmmmmm ... wonder about the sb acoustics sb17cac ceramic woofer? Price wise, it's in the ballpark of the cheaper SS and it might make a great sounding speaker mated to the neo3. Either way you go, I'm wondering how complex the crossover might become.
    Many of the SBs would work well. Meni$&$% has a sale on the SB17NAC and SB15NRX would work great. The tweeter crossover is simple and would just need a little tweaking.

    Leave a comment:


  • Kornbread
    replied
    The P looks to be a little smoother from ~1-4k without quite the ringing? from +6k, although, the P does begin a rise at ~4k. Some of the SS can get quite $ expensive. Hmmmmm ... wonder about the sb acoustics sb17cac ceramic woofer? Price wise, it's in the ballpark of the cheaper SS and it might make a great sounding speaker mated to the neo3. Either way you go, I'm wondering how complex the crossover might become.

    Leave a comment:


  • jimbones
    replied
    Originally posted by Kornbread View Post
    Alto mates the neo3 with an 8" driver? Even if the 8" plays to 3k cleanly, am I correct in thinking directivity (is that a word?) will be a major issue? Generally speaking, a smaller woofer will more easily mate with the ribbon as far as freq and directivity is concerned.
    Yuk, I spy some nasty bumps in Stereophile's measured impedance plot where they should be audible.
    Maybe use an RS180P instead? I could also go for something in the scan speak line as that would be new to me.

    Leave a comment:

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