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Old 14th December 2010, 07:10 PM   #41
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Location: The frigid midwest
Default Tymphany / LAT700 arrived

I just received my LAT700 woofer, .NOT. exactly sure
how or what I am actually going to use it for...
For 200.00 and change, What the heck???
Very well made device to be sure...
looks promising.

(not sure if I should buy another one...?)
scary hobby... *obsession* this is...

Any thoughts on a N Ripol approximating
ideal cabinet dimensions with this funky
shape. I am going to experiment.

The other matter is horizontal or
vertical positioning of driver?
What would seem best.
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Old 15th December 2010, 04:17 AM   #42
sendler is offline sendler  United States
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Default Ripole advantage

Quote:
Originally Posted by mige0 View Post
The "mass loading" saga of Ripols is mainly just that.

What looks as to be a down-shift in low cut is *mainly* a illusion caused by the SPL suck out towards higher frequencies.
Or in other words - we sadly do not gain anything - SPL wise. Maybe 1-2 dB at around 20Hz at best.

Ripole might be interesting for all-passive guys though, as it needs less EQing - despite the peak.

For optimization of SPL versus volume sadly its the wrong direction.

Michael
The big advantage of RiPol over H frame is you can cram two drivers into the space that one driver and H frame would take up while also maintaining the biggest dipole distance per cabinet volume of room space used up. The full N frame seems to be your favorite but needs to have the vicious artifact at 160Hz cleaned up. The deep RiPol goes the lowest with the least cut at the top but is also not very flat in it's intended passband. The small RiPol is beautifully flat to 170Hz but won't play as low due to the shorter dipole distance. Maybe something in between the three in terms of pipe length and taper.
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Old 15th December 2010, 10:30 AM   #43
mige0 is offline mige0  Austria
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A single LAT might not be large enough to make too much of difference in directivity either way, assumed, you use it as sub - meaning - whether you use it vertically or horizontally does not matter.
For ideas on how to use it you may get inspiration of Transar speakers - or just cut a biiiig baffle and set it into the middle.

Michael


Quote:
Originally Posted by Mike Mount View Post
I just received my LAT700 woofer, .NOT. exactly sure
how or what I am actually going to use it for...
For 200.00 and change, What the heck???
Very well made device to be sure...
looks promising.

(not sure if I should buy another one...?)
scary hobby... *obsession* this is...

Any thoughts on a N Ripol approximating
ideal cabinet dimensions with this funky
shape. I am going to experiment.

The other matter is horizontal or
vertical positioning of driver?
What would seem best.
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Old 15th December 2010, 10:54 AM   #44
mige0 is offline mige0  Austria
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Default DFD / Deep Frame Dipole sub-woofer

Yes, for any "active guy", the N-shape Deep Frame Dipole offers the best bang for the buck when it comes to SPL capability at (relatively) limited volume.

Listening to this for a few days now, either fullrange / no-EQing solo or with a Beyma 18G40 (also fullrange / no-EQing) in parallel, does not reveal any nastiness - quite in contrary - big instrumentation classical music is already great to listen to.

The wide "space" in the lower - and especially in the bottom end - department is rendered veeeery nicely in my small listening room.


Michael



Quote:
Originally Posted by sendler View Post
The big advantage of RiPol over H frame is you can cram two drivers into the space that one driver and H frame would take up while also maintaining the biggest dipole distance per cabinet volume of room space used up. The full N frame seems to be your favorite but needs to have the vicious artifact at 160Hz cleaned up. The deep RiPol goes the lowest with the least cut at the top but is also not very flat in it's intended passband. The small RiPol is beautifully flat to 170Hz but won't play as low due to the shorter dipole distance. Maybe something in between the three in terms of pipe length and taper.

Last edited by mige0; 15th December 2010 at 11:00 AM.
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Old 15th December 2010, 11:29 AM   #45
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Thanks Michael, (and others here)

I am studying/researching all of the possibilities, I want to be clear, that I am not being lazy and trying to have you and others do the foot work for me. More in that there is a wealth of knowledge (here) on a subject that I have only begun to scratch the surface on... I want to draw from the greater body of knowledge, so that as I proceed, I am not stumbling and bumbling about in a relatively new sub concept (to me).

What I think that I beginning to see here, is that multiple small(ish) drivers for speed and finesse and *need* to build a push-pull to have a more linear impedance load to amplifier, due to greater cone excursions, is growing mute with this inherent design.

In other words *properly loaded* BIG A$$ driver(s), 12-15" is better from an air movement and acoustic coupling or mechanical loading standpoint?? Push - Pull becomes less a factor, less important with larger drivers with inherently lower overall excursion.
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Old 15th December 2010, 06:15 PM   #46
tb46 is offline tb46  United States
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Default DFD and DFR(?)

Hi mige0,

Interesting subject, a while back I started out designing a Ripole around the Peavey 1801-8 (as I happen to have some), and then decided that this may be something for the MCM 55-2421 if used in multiples. You are adding a whole new twist to the subject.

Where do I find the design details for what you have been listening to: "...Listening to this for a few days...", and what would you think about something along the lines of the attached sketch.

Also, do you have any suggestions on modelling this type of enclosure in Hornresp?

Regards,
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File Type: pdf Doodles on ripoles.pdf (44.7 KB, 187 views)
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Old 15th December 2010, 06:54 PM   #47
mige0 is offline mige0  Austria
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Default DFD / Deep Frame Dipole sub-woofer

Quote:
Originally Posted by Mike Mount View Post

Push - Pull becomes less a factor, less important with larger drivers with inherently lower overall excursion.
Push pull - at least in theory - lowers even order distortion, which, by some, is seen as a benefit.
In praxis this may be of no big relevance, especially as IMO distortion with Deep Frame Dipoles is *first* not any easy to measure and plots are very questionable, and *second* because the mechanism of distributed drivers along a pipe have special properties - not that well researched yet, and *third* no one (to my knowledge) has done any research in correlating harmonic distortion to perception with pronounced CMP systems.


Quote:
Originally Posted by Mike Mount View Post

In other words *properly loaded* BIG A$$ driver(s), 12-15" is better from an air movement and acoustic coupling or mechanical loading standpoint?? .
Regarding what better to use: several small or few big chassis, well actually there is no big difference I can see as long as the sum of displacement volume is the same *plus* dipole separation, arrangement and mouth area is also kept the same.



Quote:
Originally Posted by tb46 View Post
Also, do you have any suggestions on modeling this type of enclosure in Hornresp?
IMO there is no way to really correctly simulate Deep Frame Dipole speakers right know.

Hornresp does not allow for multiple chassis arranged freely and AJHorn (current version 6) I actually bought for the purpose does allow for arranging two „distributed“ chassis along a pipe of variable shape, *but* does not allow to mirror this arrangement for dipole calculation and also has some IMO severe limitations as sound sources are possibly rather been simulated as to be point sources which does not exactly apply to two 15“ in a 80 cm pipe for example (at least measurements and simus are not *that* close).

With AJHorn one can get at least a rough feeling about changes in pipe shape and some other parameter variations of distributed Drivers in a pipe though.
Also AJHorn has a nice feature in modeling Helmholtz resonators that can freely be placed (within limits) and could be used to "notch" the Ripole peak for example.


Quote:
Originally Posted by tb46 View Post
and what would you think about something along the lines of the attached sketch.
The attached sketch looks nice – but as said above – I do not think there is anything substantial to gain with respect to less chassis stuffed in.


Quote:
Originally Posted by tb46 View Post
Where do I find the design details for what you have been listening to: "...Listening to this for a few days...", a
I've been listening to all above variants, no one is any bad.
But as said, out of reasons based on my requirements the N-shaped Deep Frame Dipole got the most attention and most extended listening so far (besides the compact Ripole that I have built some time back).

Michael

Last edited by mige0; 15th December 2010 at 07:16 PM.
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Old 20th December 2010, 10:17 PM   #48
soho54 is offline soho54  United States
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Quote:
Originally Posted by mige0 View Post
IMO there is no way to really correctly simulate Deep Frame Dipole speakers right know.
Ack, ma back!
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Old 21st January 2011, 05:20 PM   #49
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A friend is about to start a project with up to 8 12" units per side, will look forward to see how they perform.
Will look through the rest of this thread later
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Old 15th August 2011, 05:26 PM   #50
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Hello, after studying Linkwitz basic dipole equations I understand that the best way to improve the SPL without decreasing the lobe peak is to stack the drivers vertically instead of horizontally (as in figure) so keeping the distance D between the front dipole (polarity +) from rear ( polarity -) the same as used in the compound box. Otherwise , if you use small drivers stacked vertically with the same original area of a larger driver, you will decrease D and increase the lobe peak thus improving the useful frequency range at the same time the SPL.
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