What to do with Beyma 12P80ND drivers

[tmuikku]

^ Yes, thinking it through got me to same conclusion, there seems to be better loudspeaker system designs with different trade-offs with perhaps better end results. This is the reason why one would be better off selling them, then design a system from ground up and buy drivers that are suitable for it. Unless the reason to continue with it is spending time with the hobby without much expectations, fun time 🙂

 

[vinylnvalves]

Last time i downloaded Leonard Audio Transmission line program, i had to dig the file up, on archive.org to make it work. The publicly available one that pops up on google searches i had no luck with. Have not tried it on Win 11 though if that is what you have.

https://web.archive.org/web/20170506211617/http://leonardaudio.co.uk/transmission-line/download/
https://web.archive.org/web/20161204124932/http://www.leonardaudio.co.uk/software/setup.exe

Bug fix list for all versions
https://web.archive.org/web/20170516170631/http://leonardaudio.co.uk/

Latest user manual v. 3.6.3.4
https://web.archive.org/web/2016120...k/wp-content/uploads/2013/12/TL-UserGuide.pdf

👍
I know when they are from, you even have participated in some of them, still is the best collection of threads concerning alternate enclosures for the 12p80nd, as far as i know. I have the same drivers (V2.0) lying in the basement.

And yes tapering the line has a nice beneficial side effect, taper ratios of 10:1 or similar is popular due to that fact.

The 12p80s main issue partnered with the TPL from my POV , the horn forces it to cross over higher then ideal, if you wish to match directivity at xo.
So you suffer in coherency and vertical dispersion, pushing the xo upwards with a large CTC distance. Being large AMTs the vertical is already compromised by it's design.
There is also a objectionable resonance for some at 1,6k which is in the desired XO region.
IMO a TPL with backchamber modification, and possibly the lens that was posted here, attention to diaphragm etc.
Will let it play clean down to 1200, but that requires a new Horn/WG for a good directivity match to the cone below.
So a different beast altogether, and time consuming/expensive.

I have a horn that goes down to 800 Hz for the TPL. The acoustic lenses that oneoclock shared clean up the TPL making it a worthwhile challenge. I also have a mid range AMT driver - which i currently use from 350Hz to 8K Hz with a Supravox 400 below it - which is the bench mark to beat. But where is the fun if we arent trying different options.

 

[GM]

Only if the other two sides are flat angled panels, which I don't think is the case here 🙂.

Yeah, a sleep deprived 'knee jerk' brain fart from one of the guys 'correcting' folks it was a conical? flare.

 

[jccart]

Having had a pair of 12P80nds gathering dust for the last 6 years - i have been pondering do i use them or sell them. I saw this speaker over the weekend which got me thinking
https://www.abacus-electronics.de/produkte/aktivlautsprecher/oscara/oscara-212.html. I have a pair of TPLs , the 12P80nds and some seas subwoofer drivers all spare that could be used. The challenge with AMTs has been integrating them with other drivers. The 12P80nd was meant to be a good match, but i didn't like it when i tried them in a simple box a while back. So could the answer be trying a different box....... I know some will shout out dipole, however if you use the TPL's open baffle, they are bipole not dipole and you get some horrible interactions, from my experience mixing dipole and bipole.. So i was thinking monopole upto a 1000hz and then bipole or hornloaded TPL's above that with higher DI, if needed

So how to best use the 12P80nd... well i was thinking a terminated transmission line - so will effectively get a infinite baffle response. I modelled a logarithmic spiral as a first pass, not the most efficient use of cabinet space. Am i right in assuming that as the driver will only be covering frequency's up to 1.5k smoothing out features smaller than a wave length wont add much. I have the CNC so can make what ever shape of transmission path i like.
View attachment 1153234
To manage the beaming of the 12" drivers i was thinking of trying something like this first to see if it works that well I have some 12mm Perspex to make a test waveguide.
.View attachment 1153238

I am interested in making a apatite like the jbl could you pls let me know how your going to go about making yours ? are you going to use a programme to copy the shape of the jbl one then scale it up and print it to trace onto the perspex ?

 

[vinylnvalves]

Non of the sides dont need to parallel, the world is my oyster with CNC. 🙂

Downloaded the latest version of Hornresp to get the TL wizard. Its definitely doesnt like this driver as its says TL wizard not valid for drivers with a qt less than 0.2

 

[LewinskiH01]

I also have a mid range AMT driver - which i currently use from 350Hz to 8K Hz with a Supravox 400 below it - which is the bench mark to beat.

What is the midrange AMT driver?

 

[David McBean]

Downloaded the latest version of Hornresp to get the TL wizard.

Just to clarify, the TL Design tool can help in "optimising" the design of an open-ended offset driver transmission line system (employing methods developed by Martin King and Brian Steele). It is not intended to be used if the design has a closed end and the driver is not offset, as shown in your first post.

 

[David McBean]

Use the Loudspeaker Wizard.

The Loudspeaker Wizard is different to the TL Design tool.

 

[vinylnvalves]

What is the midrange AMT driver?

Some Bel E500 ‘s by Bernd Lohmann. He was selling them early about 10 years ago, them seemed to stop.

 

[vinylnvalves]

Last time i downloaded Leonard Audio Transmission line program, i had to dig the file up, on archive.org to make it work. The publicly available one that pops up on google searches i had no luck with. Have not tried it on Win 11 though if that is what you have.

https://web.archive.org/web/20170506211617/http://leonardaudio.co.uk/transmission-line/download/
https://web.archive.org/web/20161204124932/http://www.leonardaudio.co.uk/software/setup.exe

Bug fix list for all versions
https://web.archive.org/web/20170516170631/http://leonardaudio.co.uk/

Latest user manual v. 3.6.3.4
https://web.archive.org/web/2016120...k/wp-content/uploads/2013/12/TL-UserGuide.pdf

👍
I know when they are from, you even have participated in some of them, still is the best collection of threads concerning alternate enclosures for the 12p80nd, as far as i know. I have the same drivers (V2.0) lying in the basement.

And yes tapering the line has a nice beneficial side effect, taper ratios of 10:1 or similar is popular due to that fact.

The 12p80s main issue partnered with the TPL from my POV , the horn forces it to cross over higher then ideal, if you wish to match directivity at xo.
So you suffer in coherency and vertical dispersion, pushing the xo upwards with a large CTC distance. Being large AMTs the vertical is already compromised by it's design.
There is also a objectionable resonance for some at 1,6k which is in the desired XO region.
IMO a TPL with backchamber modification, and possibly the lens that was posted here, attention to diaphragm etc.
Will let it play clean down to 1200, but that requires a new Horn/WG for a good directivity match to the cone below.
So a different beast altogether, and time consuming/expensive.

Thanks for the links to the old versions of the leonard audio software. Unfortunately it doesnt run - even when i try running it in compatibility mode. Not being completely IT literate i dont understand the error. See attached. On the challenges with the AMT - the work done by oneoclock on the acoustic filter and him showing the objectionable resonance was actually a reflection in the mouth of the horn, remove alot of the challenges. The horn profile issue i had stumbled on them, i designed my own horn, to get down to 800Hz. Yes with a little bit of work - maybe in ATH4 or my original clothoid approach - will yield a better horn.