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Finalist speakers, Tower version. Advice needed concerning TL vs Ported

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  • ontariomaximus
    replied
    Hi Paul, what is the width of the RS225 TL above? And if I scale it up for 2 x RS225, what happens to the port?. I might go a little less than 2.0X. Maybe 1.7X
    thanks

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  • Paul K.
    replied
    If you want the same bass extension (f3), the line and cabinet volume will have to double (the line's length would stay the same). That's going to end up as a pretty big box, don't you think? The design center for the single-woofer version is the center of the woofer, its location along the line's length; with two woofers the design center becomes the midpoint of the two woofers which entails some finagling. And, of course, the port area will need enlarging in order to maintain the same air velocity characteristics.
    Paul

    Originally posted by ontariomaximus View Post

    Hi Paul,
    I have a quad of RS225's and was wondering about adapting this design for 2 woofers instead of one. Can you assist?

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  • ontariomaximus
    replied
    whoops double post

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  • ontariomaximus
    replied
    Originally posted by Paul K. View Post
    I designed the ML-TL for the RS225 in the Finalist back in 2014. I'm attaching the cabinet drawing (for just the TL part) and the predicted anechoic system bass response (red line) from the TL modeling. An ML-TL with the same line volume will usually have an f3 several Hz lower than an equivalent tapered TL, while the tapered TL will usually have a significantly lower air velocity in its terminus than that in the port of an ML-TL for the same SPL output.
    Paul
    Click image for larger version Name:	Finalists ML-TL Response.gif Views:	1 Size:	6.0 KB ID:	1401918
    Click image for larger version Name:	Finalists ML-TL Woofer Compartment.jpg Views:	1 Size:	297.9 KB ID:	1401919
    Hi Paul,
    I have a quad of RS225's and was wondering about adapting this design for 2 woofers instead of one. Can you assist?

    Leave a comment:


  • johngalt47
    replied
    Well, I have intended to build Finalists for a long time and have a pair of the NE149s so I'm good to go.

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  • Jim Holtz
    replied
    Originally posted by skatz View Post
    The 8 ohm NE149 is available, maybe it can be used with suitable XO adjustments.
    Yes, that's a possibility if Curt had time and a pair of Finalists to develop with. He's so busy with work, home and family he is struggling to keep his head above water.

    Jim

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  • skatz
    replied
    The 8 ohm NE149 is available, maybe it can be used with suitable XO adjustments.

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  • Jim Holtz
    replied
    A dentists dream except they've blown all their money on drugs. :-)

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  • PWR RYD
    replied
    Originally posted by Jim Holtz View Post

    Now the bad news, the NE149-4 is NLA here in the US. No one is stocking it due to the distributor increase minimum purchase to 500 units. Solen may have some but I've not checked.

    Jim

    Click image for larger version

Name:	vc192.jpg
Views:	584
Size:	53.6 KB
ID:	1413764

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  • Paul K.
    replied
    The internal width should be the same at that for the Finalist which I seem to recall is 9.5".
    Paul

    Originally posted by johngalt47 View Post

    Paul, how wide is that cabinet?

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  • Jim Holtz
    replied
    Originally posted by johngalt47 View Post

    Paul, how wide is that cabinet?
    Hi John,

    I'm not Paul but here's the TL cabinet for the Finalists on Curt's website. http://speakerdesignworks.com/Finalists_3.html

    Now the bad news, the NE149-4 is NLA here in the US. No one is stocking it due to the distributor increase minimum purchase to 500 units. Solen may have some but I've not checked.

    Jim

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  • johngalt47
    replied
    Originally posted by Paul K. View Post
    Was able to dig up more specifics. As I designed the ML-TL for the Finalists' woofer in 2014, as shown in the cabinet drawing in this thread, with a 55-watt input the system generated 105 dB SPL, the woofer's excursion was Xmax+15% (8 mm Peak), and the peak port air velocity was 14 m/s at 30 Hz. This woofer excursion was reached at 45 Hz, again at 28 Hz, then exceeded at all lower frequencies.

    A TL won't necessarily provide better bass extension than another type of enclosure and the TL enclosure will likely be a bit larger in order to have the same f3, for instance, and the cabinet is a bit more complicated to build, but if properly designed and built as designed, the bass quality is rewarding IMO.
    Paul


    Paul, how wide is that cabinet?

    Leave a comment:


  • Jesse055
    replied
    Originally posted by Paul K. View Post
    Was able to dig up more specifics. As I designed the ML-TL for the Finalists' woofer in 2014, as shown in the cabinet drawing in this thread, with a 55-watt input the system generated 105 dB SPL, the woofer's excursion was Xmax+15% (8 mm Peak), and the peak port air velocity was 14 m/s at 30 Hz. This woofer excursion was reached at 45 Hz, again at 28 Hz, then exceeded at all lower frequencies.

    A TL won't necessarily provide better bass extension than another type of enclosure and the TL enclosure will likely be a bit larger in order to have the same f3, for instance, and the cabinet is a bit more complicated to build, but if properly designed and built as designed, the bass quality is rewarding IMO.
    Paul


    My limited experience with a TL it did seem the bass notes are more differentiated but maybe that was bias as it not that obvious. As for space because the finalist isn’t a tower originally, the form factor really doesn’t change so we have the additional space. Thanks I will soon build the ML-TL version.

    Leave a comment:


  • Paul K.
    replied
    Was able to dig up more specifics. As I designed the ML-TL for the Finalists' woofer in 2014, as shown in the cabinet drawing in this thread, with a 55-watt input the system generated 105 dB SPL, the woofer's excursion was Xmax+15% (8 mm Peak), and the peak port air velocity was 14 m/s at 30 Hz. This woofer excursion was reached at 45 Hz, again at 28 Hz, then exceeded at all lower frequencies.

    A TL won't necessarily provide better bass extension than another type of enclosure and the TL enclosure will likely be a bit larger in order to have the same f3, for instance, and the cabinet is a bit more complicated to build, but if properly designed and built as designed, the bass quality is rewarding IMO.
    Paul

    Originally posted by Jesse055 View Post

    Thanks, I believe am am going to try the ML-TL. In your opinion, is there a significant differmrvr in bass extension or bass quality(I like to call it bass texture). I would assume you must see a difference or I don’t think you would design hem with TL or ML-TL. Nonetheless, your opinion without my assumptions would be better.

    Leave a comment:


  • Jesse055
    replied
    Originally posted by Paul K. View Post
    When I design an ML-TL, and once I've determined the optimum tuning frequency, I increase the input power to cause the woofer's excursion to reach Xmax+15%. Then I look at what the peak port air velocity is and where the peak occurs in frequency. If the peak air velocity doesn't exceed 5% of the speed of sound (17 m/s), I pronounce it "good", but if it does but the frequency of the peak is not likely to be excited by normal musical content, I pronounce it "good". I can't quickly find right now how the Finalists' port performed but I have no doubt there should be no problem with port noise.
    Paul


    Thanks, I believe I am going to try the ML-TL. In your opinion, is there a significant difference in bass extension or bass quality(I like to call it bass texture). I would assume you must see a difference or I don’t think you would design them with TL or ML-TL. Nonetheless, your opinion without my assumptions would be better.
    Last edited by Jesse055; 02-24-2019, 09:04 PM. Reason: typo corrections

    Leave a comment:

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