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Multi-Way Conventional loudspeakers with crossovers

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Old 21st August 2012, 02:05 PM   #121
smf is offline smf  United Kingdom
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John - I just watched your video clip. Very interesting. What sort of horn are you intending to add? This is definitely on my to do list now - I've just got some 5mm plywood to start experimenting with. I need to find some cheap drivers here in Hong Kong now.
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Old 21st August 2012, 04:54 PM   #122
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Quote:
Originally Posted by Tom Danley View Post
Hi Art
The TAD drivers are a bit unusual in that they generally have a very low (for a compression driver) resonant frequency and so the traditional series cap leaves them fully un-damped and easy for the diaphragm to move around.

What works much better is a driver with a higher Fs and more excursion capability and then using a parallel choke as the final element across the driver. This way instead of seeing an open circuit as the frequency falls, it sees a short and is highly damped and very hard for external pressure to move around.
I try to use that L as the majority of the compensation slope involved so they are typically a fairly small value as well. In some cases, the L is small enough to make the compression drivers impedance a non-issue as well as it dominates the crossover load..
Has it been unusually hot and dry in your neck of the woods (or desert) this year (like it has been here)?
The only upside is very few mosquitoes.
Best,
Tom
Tom,

Good crossover tips.

Just took a trailer trip up to Minnesota where the mosquito is the state bird and did not get a single bite there or anywhere further east all the way to Pennsylvania. There seem to be some pockets of wet areas but a lot of brown corn, food prices will be going up.
It has been super dry here except for a few gully-washers. My well is only producing slightly more water than we need, if things get any worse will have to co-ordinate clothes washing with my two neighbors who I provide water for...
Are any of your current designs using mid and high drivers on the same Paraline?

Art
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Old 23rd August 2012, 03:48 AM   #123
JLH is offline JLH  United States
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Quote:
Originally Posted by smf View Post
John - I just watched your video clip. Very interesting. What sort of horn are you intending to add? This is definitely on my to do list now - I've just got some 5mm plywood to start experimenting with. I need to find some cheap drivers here in Hong Kong now.
A simple wave guide bent at 90 degrees that has a 2" X 16" mouth. This paraline is going into my friend's show car. They will be mounted under the dash. These were to be just proof of concept. I'm completely satisfied that having the mids on the paraline is feasible, practical and quite desirable. The next ones I build will be for home Hi-Fi. Those will be a much more serious and exacting design than the current ones.
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Ah, how beautifully the orchestra sounds before a rain! In a dry sunny day there is no way for the instruments to sound this way!
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Old 23rd August 2012, 03:24 PM   #124
croat47 is offline croat47  United States
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All the examples shown here seem to be for drivers with sealed backs. Are there any reasons that this could not be applied to an open-backed driver like a HiVi B3 or old paper coned tweeter?
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Aaron
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Old 23rd August 2012, 03:46 PM   #125
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All the examples shown here seem to be for drivers with sealed backs. Are there any reasons that this could not be applied to an open-backed driver like a HiVi B3 or old paper coned tweeter?
You can do U-Frames, H-Frames, back loaded horns and tapped horns with a Paraline. It just depends on where you put the back wave.

Click the image to open in full size.

I am particularly interested in something like a W-Horn. Basically you modify the mouth of the Paraline, and leave a gap so that the woofer can sit in the mouth. This has some neat advantages:
  • The Paraline rolls off the highs. By putting the woofer outside of the line, you could potentially do a full range Paraline, similar to the Fostex boxes sold by Madisound. (Basically, you're never going to have a single driver Paraline with a sealed rear chamber, because the Paraline rolls the highs off too much. The only way you're going to get full range with a sealed rear chamber is if you have a compression driver *and* some midranges in there, like the Paralines that John and I have posted videos of.)
  • One of the reasons that a tapped horn has limited bandwidth is that you get a ton of comb filtering. For instance, with a tapped horn that's tuned to 80hz, you'll get a deep notch at 240hz if my memory is correct. But with a W-Horn Paraline, you can adjust the height of the Paraline to filter out the highs. If you do this carefully, you could likely get something close to full range performance out of one driver.

Again, all the same rules apply as any other horn. The Paraline isn't a new type of horn, it's just a new folding scheme. You can easily do back loaded horns with it.


I posted some pics of a NEO8 Paraline Dipole I did.

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Old 23rd August 2012, 04:03 PM   #126
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Patrick Bateman,
I don't see any reason that what you are proposing wouldn't work. That looks an awful lot like some old RCA W-cabinets that I had to move around when I was much younger....

What I do see is if you married a bass horn like this with a Paraline you would need to include an electronic time alignment correction factor due to the extreme difference in length of the signal paths.
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Old 23rd August 2012, 10:04 PM   #127
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Quote:
Originally Posted by JLH View Post
A simple wave guide bent at 90 degrees that has a 2" X 16" mouth. This paraline is going into my friend's show car. They will be mounted under the dash. These were to be just proof of concept. I'm completely satisfied that having the mids on the paraline is feasible, practical and quite desirable. The next ones I build will be for home Hi-Fi. Those will be a much more serious and exacting design than the current ones.
Hello John,
If you don't mind me asking is the plan to physically aim the horns for crossfiring? Fire straight ahead or use some of the techniques Patrick had mentioned to shape the wavefront? I'm still trying to grasp how to do that... Or maybe it's just a one seater using digital time alignment?

Sorry all the questions were in reference to the car. I know it's just a proof of concept, but it sounds great. (the horn and the car idea. )

Last edited by fuji6; 23rd August 2012 at 10:11 PM.
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Old 26th August 2012, 10:14 PM   #128
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So I've been reading, studying, and thinking trying to figure this out. I've got some ideas but none of them seem to hold up in all aspects.....

Quote:
Originally Posted by JLH View Post
I'm looking to run the RDC3TA from 300Hz to about 1.9KHz.
So how do we determine the size of the paraline? Earlier in the thread there was talk of sizing the radius to a 1/4 wl of the lowest freq we want to produce. 1/4 wl of 300hz is about 11", and from your pics the radius of your paraline looks to be about 5"? Does the horn the paraline attaches to determine the lower cutoff, rather than the radius of the paraline? I'd guess we use the radius to determine the vertical window.........

I'm thinking about taking advantage of the long weekend coming up and getting some paralines built, but I'm not yet sure how to size it properly. FWIW I'm going to be using the 4" closed back Celestions (got a box coming so I'll make several driver mounting plates and play around) down to 250hz on a 60x40 conical with the little BMS 4524 CD.
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Old 26th August 2012, 11:41 PM   #129
winslow is offline winslow  United States
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Needs to learn more so I can do a paraline on the rear deck of my car for some larger midbasses...put the edge of the paraline all the way out to the edge of the interior of the car so they aren't straight behind the head.
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Old 27th August 2012, 12:42 AM   #130
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Quote:
Originally Posted by natehansen66 View Post
So I've been reading, studying, and thinking trying to figure this out. I've got some ideas but none of them seem to hold up in all aspects.....



So how do we determine the size of the paraline? Earlier in the thread there was talk of sizing the radius to a 1/4 wl of the lowest freq we want to produce. 1/4 wl of 300hz is about 11", and from your pics the radius of your paraline looks to be about 5"? Does the horn the paraline attaches to determine the lower cutoff, rather than the radius of the paraline? I'd guess we use the radius to determine the vertical window.........

I'm thinking about taking advantage of the long weekend coming up and getting some paralines built, but I'm not yet sure how to size it properly. FWIW I'm going to be using the 4" closed back Celestions (got a box coming so I'll make several driver mounting plates and play around) down to 250hz on a 60x40 conical with the little BMS 4524 CD.
Hornresp can get you in the ballpark. The wave expands radially. So the area of the horn throat is equal to the mouth of the compression driver. And then the mouth area depends on how far away you are from the throat. For instance, if you are 40cm away from the throat, the area is (2 * 3.14159 * 40cm * 0.635) or 159.59. (this assumes an internal height of 0.635)

Yes, the Paraline is eye-shaped, but the sound expands in rings.

Also, these things are so easy to build, you might just skip Hornresp and head straight to the garage. I can build a Paraline in under an hour.

If you skip Hornresp, just remember the quarter wave resonance will be equal to the speed of sound divided by the height of the Paraline divided by two.
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