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

[ontariomaximus]

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

[Paul K.]

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

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?

[ontariomaximus]

whoops double post

[ontariomaximus]

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

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?

[johngalt47]

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

[Jim Holtz]

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

[skatz]

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

[Jim Holtz]

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

[PWR RYD]

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

[Paul K.]

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

Paul, how wide is that cabinet?

[Jim Holtz]

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

[johngalt47]

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?

[Jesse055]

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.

[Paul K.]

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

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.

[Jesse055]

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.