6th order bandpass design for dual 6.5"

[permo]

Hi permo,

Let's compare the dual T-TQWT v. a (much bigger) TH-both @ Xmax-in Hornresp.

Regards,

Wow, very similar curves. Very similar.

Apparently T-TQWT is going to be the winner here.

 

[tb46]

Hi permo,

I wouldn't call those curves in Post #40 similar? Anyway, I agree that while the TH outperforms the T-TQWT by a wide margin for a given number of enclosures, by SPL/ft^3 the T-TQWT is way ahead.

Regards,

 

[ODougbo]

Oliver, can you check a sim please? (post #24) 4 of these drivers in a 2.5 cf box with a 10PR looks great, and no weight added to the PR.

PR Specifications:

• Fs: 20 Hz
• Vas: 3.88 cu. ft.
• Qms: 2.50
• Cms: .67 mm/N
• Mms: 100 g
• Rms: 4.89 kg/s
• Sd: 340 sq. cm.
• Xmax: 10 mm
• Dimensions: Overall diameter: 10-5/8", Cutout diameter: 9", Depth: 2-3/4".

Hi permo,

I wouldn't call those curves in Post #40 similar? Anyway, I agree that while the TH outperforms the T-TQWT by a wide margin for a given number of enclosures, by SPL/ft^3 the T-TQWT is way ahead.

Regards,

 

[permo]

Hi permo,

I wouldn't call those curves in Post #40 similar? Anyway, I agree that while the TH outperforms the T-TQWT by a wide margin for a given number of enclosures, by SPL/ft^3 the T-TQWT is way ahead.

Regards,

I thought that the main difference was in amplitude. the response curves seemed similar.

 

[tb46]

Hi ODougbo,

As a caveat, I'm not the one to ask to check WinISD simultions. I'm just trying to get comfortable with the program. Anyway, I'll attach what I came up with, and I tried to get all the entered parameters in the picture so you can compare yours and mine (I'm doing all this on the fly, and mistakes do sneak in.)

As to posting pictures: I grab whatever I need with Gandwin PrintScreen (free), arrange the individual pictures in Picture Publisher (an "ancient" copy), and post as a jpg.

Regards,

 

[tb46]

Hi permo,

It's all in the eyes of the beholder, isn't it. 🙂

Regards,

 

[ODougbo]

Thanks for looking at that; yes there was a small error, the VAS for the PR is 3.88cf not 3.88 liters.

I should have shown the parameters also.

Gandwin PrintScreen.........hmmmm


btw....I forgot to say Iso Box, so glad you picked up on that.

Hi ODougbo,

As a caveat, I'm not the one to ask to check WinISD simultions. I'm just trying to get comfortable with the program. Anyway, I'll attach what I came up with, and I tried to get all the entered parameters in the picture so you can compare yours and mine (I'm doing all this on the fly, and mistakes do sneak in.)

As to posting pictures: I grab whatever I need with Gandwin PrintScreen (free), arrange the individual pictures in Picture Publisher (an "ancient" copy), and post as a jpg.

Regards,

 

[permo]

mwsnap is also some great screen capture software for free.

I never thought to use a PR in a ported enclosure. I will have to play around with that.

 

[ODougbo]

Well if i did it right...it would be a simple 2.52cf box with 2 pairs of Iso mounted woffers, and one 10" PR.

Not much weight needed, if any.

 

[tb46]

Hi ODougbo,

That litres to ft^3 think sure makes a difference. 🙂 That looks a lot better, even 2 ft^3 for the box volume would be fine. Bye the way, a single driver in the same box w/ the same PR has about 3dB more output (?). Also, when I change the Sd in the PR window it does not seem to influence the simulation (bug?).

Regards,

 

[ODougbo]

Hey Oliver,

You're right the "SD" is not a factor.

I ran it with three PRs - 2 - 8", 1 - 10" and a 12", 12" was the best

Can you open the word file?

I did download the screen shot programs 😕

 

[tb46]

Hi ODougbo,

The word file opens fine, and I see what you mean. As you have the box already built can you try it out with just one 299-114 (normal, not isobaric)? Would be interesting to see if that works.

Regards,

 

[revboden]

ok doug I used the 10" PR

the pink graph is the 4 driver iso

the yellow is 2 drivers normal.

 

[revboden]

With the 12" PR the group delay is even worse

 

[revboden]

If you're using windows It has a built in screen shot. Just hit the 'function' key + 'Print screen' key, then open paint and paste it, then save as a jpeg.

 

[ODougbo]

Thanks again Rev. Results were similar to mine. I've been toying with this idea for a while.......
However the T-TQWT design is awesome, and don't know how thank you all.

 

[permo]

ok doug I used the 10" PR

the pink graph is the 4 driver iso

the yellow is 2 drivers normal.

Wow that group delay is crazy.

 

[permo]

I think Dougbo and myself are both looking to push the envelope with new designs for this driver. Personally, I think if size is not an issue the true tapped horn is the winner...it usually is. The quarter wavelength pipe is a great compromise.......if I didn't think so I wouldn't have built one!

I have no idea how to design one, but what about 8th order (three chambers or more) bandpass? I would love to see how a design like this compares to the others.....

 

[tb46]

Hi permo,

On you go to AkAbak. 🙂

Regards,

 

[permo]

Hi permo,

On you go to AkAbak. 🙂

Regards,

I can't even understand hornresponse! I will take a look tho.

I will admit, I am really good at winisd! I wish they had 8th order as an option.


I really like the TQWT design for two of these but its a little tall for my installation. I need narrow, short and long. I wonder if the build could be modified to be 40-50 inches long and reduce the number of ducts/folds?