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-   -   Collaborative Tapped horn project (http://www.diyaudio.com/forums/subwoofers/97674-collaborative-tapped-horn-project.html)

moray james 7th March 2007 06:25 PM

Have you looked at...
 
the Arnold Klayman patent? US # 3 047 090. The second drawing in this patent is especially interesting as Klayman uses a simple but very clever idea to build two lines into one box and manages to load not only the fundamental but also the first harmonic of his 1/4 wave line. Regards Moray James.

cowanaudio 7th March 2007 08:06 PM

G'day Paul

What a great idea! It's fun playing with tapped horns, and not too hard coming up with a good result. I'd join you in a heartbeat if I didn't have to drive 16 hours.

This will certainly save having to purchase the drivers yourself. All the drivers I tested were my own. I assume the baffle the driver mounts on is removable, so you can modify it or replace it to adapt different drivers? The bottom layer of the baffle could have a clearance hole for a 15" driver and remain fixed and the driver baffle could then be screwed to that.

What is the length of the line? Also it might pay to mount the drivers the other way around for more space behind the magnet.

The 830515 was very poor in my 30Hz tapped horn. The 830500 was a good performer.

Measurements are good if you can do them.

Cheers

William Cowan

moray james 7th March 2007 09:14 PM

Hey William...
 
I see you peaking out from behind those woofers! I would be interested in your comments on the Klayman dual duct design in the above patent. Since you have been sucessful in obtaining two full octaves from a single tapped horn do you think that the dual version would or could stretch another half octave? Regards Moray James.

rick57 7th March 2007 09:16 PM

Hi Paul
The PHL I measured IIRC as 390 mm centre – centre, can check on the weekend.

William’s suggestions were in one of the threads here, I search I think on ‘tapped’ and ‘Vas’.


Hi William,
Peerless– on the 5th graph at www.diy.cowanaudio.com/th.html you got more deep bass with the 830515 than the 830500 - -did you prefer the ‘top end’ of the 830500?
Is the left hand vertical line on those graphs, 10 or 20 Hz?

Thanks

cowanaudio 7th March 2007 09:46 PM

G'day Rick

I didn't notice this until now, but those graphs are labeled incorrectly. The red trace is the 830500. Many people must have thought I was crazy preferring the brown trace! The red 830500 trace is very easy to eq flat, with only one channel of PEQ. I will change the page ASAP. That plot is 20-200Hz.

Moray, I'm not sure how the Clayman design would work, I havn't played with one.

Cheers

William Cowan.

rick57 8th March 2007 01:56 AM

I tried to look up Klayman’s 1962 patent
http://patimg2.uspto.gov/.piw?Docid=...iew+first+page
but it doesn’t allow access or display for me.

Hi Moray
Would the extra half octave be at the top or boo tom end? Can you post the drawing?

Hi William
At one stage you suggested Qt of 0.2 - 0.4, FS near LF cutoff, and
VAS low. We mightn’t have time to properly test all - any further thoughts on optimum TS specs?

The 830500 is Qt of 0.17, FS of 18, and VAS of 139.

Any thoughts on how Qt of 0.35, FS of 23, and VAS of 144 the much cheaper but well regarded CSX might be?

Cheers

cowanaudio 8th March 2007 02:04 AM

G'day Rick

Have you tried the method I describe at the bottom of this page:

http://diy.cowanaudio.com/th.html

With some discussion here:

http://www.speakerplans.com/forum/fo...TID=8329&PN=10

The CSX would be worth a look. It's not half the driver the XLS or XXLS are though.

cowanaudio 8th March 2007 04:00 AM

2 Attachment(s)
The plot is 10 to 100Hz.

moray james 8th March 2007 06:04 AM

Klayman patent...
 
2 Attachment(s)
plus another interesting US patent.

paulspencer 8th March 2007 06:05 AM

Collaborative Tapped horn project
 
To keep the other thread focused on the day I'm organising, I'm starting this thread to talk about the technical aspects of this tapped horn project. The thread to discuss the day is here:

http://www.diyaudio.com/forums/showt...threadid=97620

Here is a simulation:

http://www.geocities.com/etude316/Fo...s_basshorn.gif

Yes, it looks bad for the tapped horn, but hornresp is not simulating the full story. A tapped horn such as this is a 1/4 wave horn at 18 Hz which is what hornresp shows, but at the same time it is a 1/2 wave horn at 36 Hz. This is what hornresp doesn't show. With the correct driver, the result is that the response is flat and the dips are filled in.

The tapped horn has only one driver while the other horn has two. Note that the voltage input is the same for both at 30V.

How can it be both a 1/4 and 1/2 wave horn? The front of the driver loading into the throat gives the 1/4 wave output, while the rear of the driver located in the mouth actually sends its output towards the throat and then back again.

I'm far from understanding it fully, hence this project to try out different drivers and see how what we can measure is different from the simulation.


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