TL expert please help

[Jimmy154]

I'm building a TL and I was wondering which enclosure design is better. I would like to build the TL using the green lines instead of the red, but the red lines look like a TL MJK's Mathcad files can predict.

Will the TL with the green lines have roughly the same sound as the TL made with the red lines?

The picture is of TL that has a 10:1 taper with the 8" woofer ~29" from the bottom. The line should have a length of 80-90 inches, I believe the picture line length is ~86 inches. The inside of the enclosure should be 22" by 48" tall by 8.5." The reason I kind of want the enclosure with the green lines is because I want the mid and bass drivers close together since the speaker will be close to my head and I'm not sure how high I want to cross-over the bass and midrange.

I guess I might as well mention my drivers:

SEAS Prestige 27TDC
ScanSpeak 15S/8530K-01
21W_8555-01

I will be using the kx project drivers as my computer controlled x-cross. Yes, these will be my computer speakers

[Jimmy154]

I guess my question is stupid.

I don't know how some one can predict the different sounds of closely similar TL lines.

[bjorno]

I guess my question is stupid.

Hi Jimmy,

No, It isn't ,See the picture where suggested interconnected sections are shown that can be entered into MJK:s Sections worksheet.

As you haven't placed the driver in your picture I had to start the area counting from S0 but in the reality you should start from the driver and go towards the closed end, then from driver to the open end to allow an acoustical model to be correctly designed.

b

1(1)

[Jimmy154]

Originally posted by bjorno
No, It isn't ,See the picture where suggested interconnected sections are shown that can be entered into MJK:s Sections worksheet.

Oops, I forgot about that worksheet. I have never used it.

Originally posted by bjorno
As you haven't placed the driver in your picture I had to start the area counting from S0 but in the reality you should start from the driver and go towards the closed end, then from driver to the open end to allow an acoustical model to be correctly designed.

The woofer is located next to L2. So my sections would start at S1 -> S0 -> S2 -> S3 -> S4 -> S5 -> S6 -> SL, would that be right? Or is it: S1 -> S0 -> S1 -> S2 -> S3 -> S4 -> S5 -> S6 -> SL?

I should check out the worksheet, now.

[Jimmy154]

Thanks for the help. That worksheet was really useful because it simulates the differences in the placement of stuffing. The shape I chose didn't seem to matter much from that of a design with a top that is parallel to the bottom.

Oh that picture you made really helped me I might not have divided my sections into too few parts.

[bjorno]

Originally Posted by bjorno
I don't believe the expansion of the universe is accelerating at a faster and faster rate, but I do believe the contraction of the human brain is accelerating at a faster and faster rate.

Originally Posted by Jimmy154

Interesting thoughts about the universe and the human brain. I would have to agree.

Thanks for the help. That worksheet was really useful because it simulates the differences in the placement of stuffing. The shape I chose didn't seem to matter much from that of a design with a top that is parallel to the bottom.

Oh that picture you made really helped me I might not have divided my sections into too few parts.

Jimmy,

I don't recognize the statement ('Originally Posted by bjorno') in the quote here-above, can you show a link address where to find this?

b

[Jimmy154]

It was an attempt at an lol I take it you didn't lol, so I removed it

I think I like the design I have but I think I can do better by replacing the 21W8555 with a peerless 830500. It will be mounted on the side with a 80-100 Hz LR4 cross-over to the SS 15W. Might this be a better design? I'm not sure this is a good design with a 5" midrange, is it? Most speakers with side mounted woofers have a 6-7" midrange.

Here's are the pros for each design as I see them:

21W8555 woofer:

- 12 db/octave x-over at 200-300 or high order x-over at lower frequency
- lower distortion at lower listening levels?

Peerless 830500:

- narrower baffle and smaller enclosure
- more output

[Jimmy154]

Dang, I done did it now. I gone ahead and ostracized myself from this fine community, lol

I go with the ScanSpeaks