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Vifa 9 BGS 119/8 Alternative for Picolino 2
Vifa 9 BGS 119/8 Alternative for Picolino 2
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Old 25th August 2013, 12:15 PM   #11
xrk971 is online now xrk971  United States
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Vifa 9 BGS 119/8 Alternative for Picolino 2
Sayrum,
Thanks for tip on the coiled up TL. I have designed something similar but a straight MLTL and wall mount. I should be able to sim that no problem. Hey don't know if you remember but it was your post on a flat wall mounted TL that got me into DIY speakers back in Oct of last year.
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Old 25th August 2013, 12:20 PM   #12
xrk971 is online now xrk971  United States
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Quote:
Originally Posted by DaleHughes View Post
Wow, thanks for all the information. I appreciate you going to the bother of doing simulations for this. I'll certainly take this all into account when deciding what driver to use.

One question though, what software are you using for the simulations? Is it something someone with nothing more than a reasonable knowledge of computers and basic understanding of transmission line enclosures and speaker parameters could work with?
I use AkAbak which is a little tough to start but plenty of folks able to help you if you are interested. It has a steep learning curve but is very powerful and can simulate almost any speaker you can imagine including multiple paths, multi arbitrarily placed drivers, horns, TL, band pass, etc. Don Hills has a beginner how to thread for AkAbak that is useful to get started. Other folks use Martin J King's software in Mathcad (aka MJK ), also very good for simulating this sort of stuff but not as flexible as the sheets are "locked".
Good luck.
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Old 25th August 2013, 12:44 PM   #13
DaleHughes is offline DaleHughes  United Kingdom
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Quote:
Originally Posted by sayrum View Post
Hey,

no surprise there. Mr Timmermanns a Master of Engineering, has been publishing a diy speaker building magazin here in germany for many years and is know for his very meticulous approach.

If an easy compact build for a still available full ranger is of interest, maybe this one is for you.

Greetings
Hmm, how would the performances of these two units stack up? I could certainly save money by using this other design, and it appears to be an easier build too.
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Old 25th August 2013, 01:07 PM   #14
xrk971 is online now xrk971  United States
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Vifa 9 BGS 119/8 Alternative for Picolino 2
I will get a sim going soon. I imagine that the coiled up one will not be as good but we won't know for sure until I run the sim. KenLBird has made a tapered TL using the FR10 before and reportedly it sounds great. His is a 3 fold box rather than a coil but probably similar performance. It's in the foam core thread.
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Old 25th August 2013, 02:15 PM   #15
Scottmoose is offline Scottmoose  United Kingdom
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Quote:
Originally Posted by xrk971 View Post
My sim actually has all the folds and geometry as shown in the plans
At the risk of raining on the self-congratulation -so does mine. I even included some damping.

Quote:
folks use Martin J King's software in Mathcad (aka MJK ), also very good for simulating this sort of stuff but not as flexible as the sheets are "locked".
Really? About the only back-load the existing sheets can't do are more than 2 vent termini (my heart doth not bleed at the loss), although they could be adapted easily enough.

More generally, all of the popular software available (AJ Horn, AkAbak, Hornrsp, MJK etc.) work with plane-wave assumptions, but that's sufficient for 99.999% of the use expected of it.

Last edited by Scottmoose; 25th August 2013 at 02:30 PM.
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Old 25th August 2013, 02:29 PM   #16
xrk971 is online now xrk971  United States
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Vifa 9 BGS 119/8 Alternative for Picolino 2
Well that's great to hear that the MJK worksheet let's you do what you want. I was under the impression that the heart of the computation formulas were in the "locked down" section to protect MJK's IP. But if you say that is indeed unlocked", then certainly, Mathcad is very flexible and can do whatever you tell it to do.
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Old 25th August 2013, 02:39 PM   #17
Scottmoose is offline Scottmoose  United Kingdom
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Parts are, but there's plenty of flexibility to add sections (as many as you like), bends, changes in cross section etc. Doddle. That's what the TL sections sheet for e.g. is for. People like GM, myself & many others have used Martin's worksheets for years (along with AkAbak, Hornrsp etc.) because they're accurate, and as flexible as you need the aforementioned 99.999% of the time. If they weren't, we wouldn't use them.

Last edited by Scottmoose; 25th August 2013 at 02:52 PM.
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Old 25th August 2013, 05:08 PM   #18
sayrum is offline sayrum  Germany
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Quote:
Originally Posted by DaleHughes View Post
Hmm, how would the performances of these two units stack up? I could certainly save money by using this other design, and it appears to be an easier build too.
Hey,
i build the coiled tml. If money and availability of the right/correct driver for the design are an issue i vote for the Visaton FR10 in the coiled tml!
From what i read the Piccolino2 might be more detailed and extended in the high frequency but if you are considering building it with a missmatched driver not a good idea imo.

There are many different versions of the "pile of small boards" (translated german title of the coiled tml). Here is the sketchup model of all the available versions to download.

You might consider the Vifa 9BN119/8 = Peerless TC9FD-18-08 in this design.
Very simple to build and with the great little (+ inexpensive) driver the best bang for your buck imo!
But it does need mounting on a wall or other large flat surface (baffle step).


Quote:
Originally Posted by xrk971 View Post
Sayrum,
Thanks for tip on the coiled up TL. I have designed something similar but a straight MLTL and wall mount. I should be able to sim that no problem. Hey don't know if you remember but it was your post on a flat wall mounted TL that got me into DIY speakers back in Oct of last year.
X
Thanks xrk971
Iīm glad to be of service. I must admit that i still canīt interpret the Akabak graphs totaly

cheers

Last edited by sayrum; 25th August 2013 at 05:19 PM.
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Old 26th August 2013, 01:41 PM   #19
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Quote:
Originally Posted by sayrum View Post

If an easy compact build for a still available full ranger is of interest, maybe this one is for you.

Greetings
Here is the sim of the "Pile of Boards" or "coiled TL" as I call it. It actually looks pretty nice - and has good bass response down to 50 Hz for the very inexpensive FR10 driver. I put stuffing to damp HF up to the 3 turn (the turn from vertical downwards to the right after the driver).

The sim used the dimensions from this plan (with 100 mm width of TL channel):

Click the image to open in full size.

Plots:
- Freq response for speaker placed 8 in away from back wall mic at 1 m
- Impedance
- Driver cone displacement
- Impulse response

Summary: a well-balanced enclosure with good bass, well controlled cone movement, decent impulse response for OK group delay.
Attached Images
File Type: png Coiled-TL-FR10-Freq-1m.png (27.2 KB, 329 views)
File Type: png Coiled-TL-FR10-Impedance.png (20.5 KB, 323 views)
File Type: png Coiled-TL-FR10-Displ.png (21.5 KB, 315 views)
File Type: png Coiled-TL-FR10-Impulse.png (13.2 KB, 314 views)
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Old 26th August 2013, 01:52 PM   #20
xrk971 is online now xrk971  United States
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Quote:
Originally Posted by sayrum View Post
I must admit that i still canīt interpret the Akabak graphs totaly
cheers
The freq response curve is SPL vs frequency (the distance the mic is at is in the graph legend) and the black curve is the overall output, the red is the driver direct sound radiated, the green is typically the vent/horn output only.

The next plots typically are the electrical impedance of the driver, the driver cone displacement in mm vs freq, then sometimes I show the impulse response which gives you an idea of the group delay - you want to make sure that the main secondary pulse is < 8 ms otherwise there will be very noticeable time delay effects from say, a kick drum sound, happening way after the initial punch from the direct radiator.

Hope that helps.
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