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

[Jesse055]

Hi Jessie,

I use a tablesaw but a handsaw is also OK. The end just needs to be close and fit into the length. I use Titebond to seal the PVC in place at the the same time I'm gluing in the PVC support braces. It makes the cabinet very stiff.

Jim

Sure I will try the table saw. May need another guide. Will play on youtube. If my cuts are bad I will just MDF tunnel it. Going to be a lot of work but I know it will be worth it. Thankful to you and Curt for the design.

[Jim Holtz]

It's not hard with a table saw. lower the blade so its just through the 5/8" of PVC wall with a square edge against the guide and carefully twist the pvc until its cut all the way around. Pretty simple.

Jim

[Jesse055]

It's not hard with a table saw. lower the blade so its just through the 5/8" of PVC wall with a square edge against the guide and carefully twist the pvc until its cut all the way around. Pretty simple.

Jim

Ok I will, thanks. BTW how are the Bordeaux treating you?

[Jim Holtz]

Ok I will, thanks. BTW how are the Bordeaux treating you?

Wonderful! I love them.

Jim

[Jesse055]

Wonderful! I love them.

Jim

Once I get these Tower TL Finalist completed, those are high on the list for next project. I didn't find them on Curts website. Will hey be on his site? Where can I find the plans?

[Jim Holtz]

Once I get these Tower TL Finalist completed, those are high on the list for next project. I didn't find them on Curts website. Will hey be on his site? Where can I find the plans?

Curt is waaaay behind on his website. There are several projects that he doesn't have posted. Life has gotten in the way so speaker projects are moving at a slower pace for him.

Email me; jim (at) jholtz (dot) us and I'll send you everything. It is a large amount of pictures, drawings and a tip sheet.

Jim

[Jesse055]

Curt is waaaay behind on his website. There are several projects that he doesn't have posted. Life has gotten in the way so speaker projects are moving at a slower pace for him.

Email me; jim (at) jholtz (dot) us and I'll send you everything. It is a large amount of pictures, drawings and a tip sheet.

Jim

Totally understood as I took about 18 months off with life, lol. I will email you soon, thanks.

[JRT]

I have the drivers for about 18 months but have procrastinated the project(yes I even have the Dayton RS28F tweeters that have been discontinued). What I am debating is whether to go transmission line or ported. If the decision is to go TL then I noticed that I then have two choices for the TL. 1. The tapered TL on the Speakerdesignworks website, or 2. The non tapered ML-TL designed by Paul K.

Anyone heard or have any experience on the TL's vs the regular ported Finalist? Anyone have opinions on the two different TL versions?

Please help me decide and subjective opinions are welcome so don't hold back

Build and try both using the same drivers and a separate external crossover. The listening comparison(s) will be a good learning experience.

[Jesse055]

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

I would assume the the air velocity from your ML-TL wouldn’t be significant. Shouldn’t make a functional difference, correct? I’m leaning toward your design from what I’m understanding.

[Jesse055]

Build and try both using the same drivers and a separate external crossover. The listening comparison(s) will be a good learning experience.

Yes it would be a great experience but that’s a lot of wood and work to make both. Making one pair will be all I can really do. So I have to make my best educated guess before I build.

[Paul K.]

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

I would assume the the air velocity from your ML-TL wouldn’t be significant. Shouldn’t make a functional difference, correct? I’m leaning toward your design from what I’m understanding.

[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.

[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]

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.

[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?