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[Art Welter]

In the 80-100 HZ range, the single 15 “C horn” pictured in my previous post is around 103 dB one watt one meter. Doubling the “C horn” would bring it to 106 dB one watt one meter, in line with your expectation, but it would be about 97 dB at 40 HZ.
The above results are using  EVX150A speakers.
I would expect the Selenium 2x15” folded horn to be very similar.
The horn needs a fair amount of EQ to be “flat”, but sounds good after the EQ.

So far, I have not heard a bandpass box that sounds as good (defined bass)as a proper bass reflex or horn even though they may read a few dB louder.

[Shivraj Persaud]

http://www.cowanaudio.com/hornsubjr.html

Well then I was wrong to assume this Selenium Folded horn would have the same response as that little subwoofer.

I understand about the dB. My 15PS100s are rated at 94.5db and my friends fane 15xb colossus are rated at 99 db. I started drueliing over the db, but when I looked at the curve its about the same One is over rated and the other is not.

If what William is saving 106db and flat to 40hz is true that is one great little subwoofer.

Check out his tapped horns too... great site

[Art Welter]

Shivraj Persaud wrote on Thu, 10 December 2009 12:25

http://www.cowanaudio.com/hornsubjr.html Well then I was wrong to assume this Selenium Folded horn would have the same response as that little subwoofer. I understand about the dB. My 15PS100s are rated at 94.5db and my friends fane 15xb colossus are rated at 99 db. I started drueliing over the db, but when I looked at the curve its about the same One is over rated and the other is not. If what William is saving 106db and flat to 40hz is true that is one great little subwoofer. Check out his tapped horns too... great site

Note that the figures William Cowan is talking about are in room, corner loaded.
The short horns simply won't do that unless corner loaded.

“The horn fires into the corner at 45degrees with the horn mouth touching the two walls, creating a triangle in the corner between the top of the box and the corner itself. Firing the horn at the corner at 90 degrees raises the LF cutoff by some 5Hz, with an optimal spacing (around 300mm).”

[Shivraj Persaud]

oh I didnt realize. thats good to know.

[Shivraj Persaud]

what do you guys think about these two subs ?

http://www.speakerplans.com/index.php?id=184sub

http://www.speakerplans.com/index.php?id=x1

Is this for real?

[Caleb Dick]

What's wrong with the LAB sub?  That would be my first choice for a DIY sub.

Caleb

[Shivraj Persaud]

I actually built a labsubwoofer. Its way way too big.

[Art Welter]

Shivraj Persaud wrote on Thu, 10 December 2009 19:41

what do you guys think about these two subs ? http://www.speakerplans.com/index.php?id=184sub http://www.speakerplans.com/index.php?id=x1 Is this for real?

Very similar to  one half of the cabinet in the current
“6th order bandpass build”
thread, and easier to build.
Building two cabinets rather than one has the advantage of a stiffer cabinet, and killing one cone won’t allow the dead cone to absorb the live cone’s output.
The specs are simulated, but they look believable.

As I have said before, so far, I have not heard a bandpass box that sounds as good (defined bass) as a proper bass reflex or horn even though they may read a few dB louder.

That said, for program material that goes “boooooom booooom”, this type of cabinet could be the cat’s pajamas, especially if they were built in Rog Mogale’s temple in Tibet by a team of hand picked Shaolin masters who can support all there weight on one finger for hours .

Art Welter

[Shivraj Persaud]

Thanks Art I learned a lot from your posts and others.

I came across the Beyma 18LX60 but they are discontinuing it.
Why would they discontinue such a great woofer?

Its 18" Vas - 500L gts- 0.36 qms - 11.45 ges - 0.35

According to some program called ajdesigner it would make a really good vented box. -3dB at 30hz.

Are there any other drivers in the same ball park ?

[Ivan Beaver]

Shivraj Persaud wrote on Thu, 17 December 2009 00:18

Thanks Art I learned a lot from your posts and others. I came across the Beyma 18LX60 but they are discontinuing it. Why would they discontinue such a great woofer? Its 18" Vas - 500L gts- 0.36 qms - 11.45 ges - 0.35 According to some program called ajdesigner it would make a really good vented box. -3dB at 30hz. Are there any other drivers in the same ball park ?

Don't start getting hung up on particular drivers.  At one time you were talking horn-loading-then it went to bandpass-and not you are talking vented.

VERY different designs-with different woofer needs.  What works great in one box design may be lousy in a different box design (VERY common).

You need to settle on what type of design you want-THEN find the driver that works for THAT design.  NOT finding what you think is a "great driver" and then trying to fit a box around it.

The two (box and driver) need to bve matched to each other-jsut like a marriage.  Just because you have 2 "great" people does not mean they are compatable.