Collaborative Tapped horn project - Page 4 - diyAudio
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Old 9th March 2007, 05:22 AM   #31
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GM Greets!

http://free.patentfetcher.com/Paten...ch&PN=3+047+090



Thanks, excellent
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Old 9th March 2007, 09:17 AM   #32
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New version:

Click the image to open in full size.

Part of mouth would have to be covered (too big) but as shown it will accomodate the 15" drivers and a 430 x 430 mounting plate to be slid in to one side.

Mounting plate shown hatched.
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Old 9th March 2007, 11:46 PM   #33
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(I tried to attach moray's refenced patent, but the file was too big)

Hi Paul

So I don’t build up expectations and later find I can’t fit one in, what would be the external dimensions of the current config, if built as a settled design rather than a prototype, for 10/ 12/ 15 inch drivers?

Or even to see if I could fit one in my lounge room as well


Thanks
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Old 10th March 2007, 02:11 AM   #34
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Top drawing is 2250 x 515 and bottom drawing is 2250 x 436. Mounting plate shown hatched is 430mm square and the opening in which it fits is 450 x 450 - enough to fit any 15" driver. Hatched blue circle shows the cutout required for the PHL driver, hence the baffle hole shown there will be cut for this or for the biggest 15" that anyone is bringing. So in short, any 15" driver should fit.

I'm going to have to build this thing out of 3 sheets, no way around it. I had hoped for 2, but it's obviously not going to happen.

Are any of your drivers in pairs? I'll probably make the second baffle to suit the AV12 without mounting plate.

I'll be interested to see the impact of one vs two drivers. In the next 1-2 weeks my Rythmik Direct Servo kit is coming, not only would I like to try it tapped, but it could also be a good reference sub to compare them all against, being a servo sub. One thing I want to test is if a horn can actually get a conventional driver to compare with a servo sub. Rob Wells commented that his lab horns are very similar to servo subs, except at much higher output. This is what first really got my attention about bass horns.
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Old 10th March 2007, 02:41 PM   #35
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I would strongly recommend against using the Rythmik in a TH without consulting with Brian. My guess is that he will not recommend it either. The TH will certainly give much greater output, but there is also evidence that points towards phase distortion possibly being audible a very low frequencies and mainly at very low frequecies. I have not yet seen Gedlee AES paper so I suppose the jury is still out. I however, cannot imagine how a pair of sealed Rythmik Servo 15's would not supply sufficient low frequency output for music (or even HT for that matter) unless the room was extremely large.
The SQ is superb for music with the sealed (recommended by Brian) enclosures (low GD). I'm not saying it is because of the low GD, but having low amounts certainly can't be hurting the performance.
Keep in mind this GD is inherent in the system before XO.
Now of course if you need 120db @ 25hz at the listening position, TH's do have their appeal .

cheers,

AJ
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Old 11th March 2007, 03:27 AM   #36
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Why ask for an opinion on whether something will work when you can simply try it and find out for yourself?

I doubt I'll keep the Rythmik drivers in a tapped horn, more likely dipole or a large horn, or perhaps more short term a sealed box. This is about experimentation first and foremost. It won't be a failure unless we learn nothing. If I come out th e other end wanting to actually use a tapped horn, then that's a bonus. If not I'll re-use the MDF for something better.

If I do use the Rythmik, then I'll see if I can get a custom made servo board. Apparently only the frequency response is required.

The paper does look interesting. Geddes has done some very interesting work in the field of perception of distortion.
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Old 11th March 2007, 10:18 AM   #37
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Hi Paul,

Finally got some time to read and think about this a little.
Not attempting to pour any “cold water”, just to understand better:

Post 1 –
“With the correct driver, the result is that the response is flat and the dips are filled in”
How confident can we be of this (or if the measured response ended up close to the sims), how easy would it be to flatten the sharp notches?

Hi William,
On that note, what distance from the mouth were your measurements taken at?


Post 15 –
The PHL sims a smoother response than the AV-12, so curious why its suspected the AV12 will work out best?

“The kappa is very similar to the PHL except that it has a peak at the bottom end due to the much stronger magnet”

The BL of the Kappa Pro 12 is 17.3, the XLS 17.6, JBL 2035 and the AV-12 BL is 16.
The PHL 5320 is an ‘outlier’ in this group at 23.4. Not clear on this possible correlation?


Mounting
Is it possible to mount the drivers per Planet 10’s Push-push in post 2 Push-push phase to cancel the drivers’ Newtonian motion, and still be a tapped horn?

“Top drawing is 2250 x 515 and bottom drawing is 2250 x 436”.
Both liveable, IMHO

All my drivers are pairs, though how many will we have time to test, maybe we need a weekend?

Cheers
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Old 11th March 2007, 11:33 AM   #38
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G'day Rick, my latest version is like version 3 linked in the other thread. It's not practical to face the magnets together in this example, and I think it's best to get distortion reduction as well.

About how confident, the unknown is the drivers in question, not the concept of the tapped horn itself. William shows measurements to demonstrate it works.

I'm just speculating about which will work best. Kind of like guessing which horse will win melbourne cup.

What I am looking for though is two peaks and a dip - if there is no dip then it's not going to get filled in and then you have early rolloff and less efficiency down at the tuning point.

But we will find out when we actually measure it.

I'll allow for two drivers of each, but I just wonder if two 15s will be too much SD, but who knows. I'll allow for it anyway.

Comparing the drivers I was talking about the hornresp SPL chart, not their parameters.

If the response in reality works out like those charts, then no chance of eq, we are counting on it working out much better as hornresp isn't really set up to model it all.
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Old 11th March 2007, 11:42 AM   #39
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Are any of your drivers in pairs?

Except the CSX 10", of which the viewpont of a d-s-t engineeer is they're capable of "excellent transient response", I have four of . .
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Old 11th March 2007, 12:05 PM   #40
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All in pairs - 2 x AV12 and 2 x Rythmik (except 2nd won't have arrived in 2 months I don't think)
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