Over the last 50 years I have been building a number of speakers (Elsinore as the last one) as well as totally renovating lots of speakers (lastly Rauna Leira and Rauna Chorus/Vale). Now i have decided to build a Mass loaded Transmission Line speaker (TMLTL) from scratch, which is kind of new to me.
The decision on the below setup is based on a number of reasons such as sound stage, previous experiences, cost vs performance, physical appearance etc.
If anyone would like to join in the process you are more than welcome.
The basic cabinet calculations is done by the award winning (and very humble) Transmission line expert (which he refuses to call himself) Paul Kittinger (google him) in Martin J Kings software MathCad. That software is unfortunately not available anymore due to misuse by comercial users. The work has then continued in Hornresp, which is a great software, with almost the same result. The filling calculations are based on somewhat slightly different methods in the two softwares which create the slight differencies in outcome. The results has been explored back and forth and ended up with minor changes but pretty much the same as from the beginning with Paul and MathCad.
For midbass a number of Seas, SB Accoustic and ScanSpeak drivers has been up for discussion, exploration and design ending up with the by many highly appreciated SS D8531G00. The SB Accoustic SB17NRX2 (or MFC) will do as a budget alternative with minor changes to the design (according to simulations both in MathCad and Hornresp).
For the tweeter there could be a number of alternatives, up to high cost super tweeters. Although bot in comersial speakers as well as in the DIY world the mid price section seem to offer a number of very good alternatives from Seas, SB Accoustic, Peerless and ScanSpeak. Following the diyaudio Elsinore project for many years including the comparison of different tweeters there, I ended up with the SS D2608/91300 together with a waveguide as a starting point. This also very much from building one pair of Elsinores, helping a friend with one pair, and still having some pairs of wave guides in the basement. Hopefully it´s also where it will end up. The Elsinore is a 2,5 way speaker with a higher XO point to the tweeter. But hopefully the tweeter/WG combination will work with the lower X/O point in this design.
The basics looks like this:
- Mass loaded, Transmission Line (MLTL)
- Coupling chamber at the throat of the line(Inspiration Rauna Leira)
- Fairly simple 6/12 dB cross over (Xmachina + Xsim, Vituixcad)
- X/O point somewhere 2,3-2,8 kHz,
- Fairly standard/cheap components in the X/O (maybe except for one JA Superior Z-cap, the red one)
- 2 way with 2 drivers
- Tweeter SS D2608/91300
- Waveguide for the tweeter (from the Elsinore project here at Diyaudio)
- Midwoofer SS 18W/8531G00
- About 100 cm/40" in height, as narrow as possible
- Bass -3dB at about 32Hz Hz and -6dB at 28-29 Hz
- Partly tilted baffle
- Two versions - Four (std type of box) or six sided cabinet (inspiration Rauna Vale / Opus3 Chorus)
- MDF furniture quality, 25mm for the cabinet, 19 mm for the internal divider
- Cross over placed at the lower back of the cabinet for easy adjustments
- .......
The cross over will be based on actual measures with the drivers mounted in the cabinet. The measures will be done at different speaker positions (0,5 to 4 piradians). The software for the cross over will be explored with a number of supporting people, and softwares such Xmachina, Xsim and/or Vituixcad, REW and/or Arta etc.
Project started autumn 2020 and will continue slowly forward. Inspiration, comments, contributions etc are very welcome.
The decision on the below setup is based on a number of reasons such as sound stage, previous experiences, cost vs performance, physical appearance etc.
If anyone would like to join in the process you are more than welcome.
The basic cabinet calculations is done by the award winning (and very humble) Transmission line expert (which he refuses to call himself) Paul Kittinger (google him) in Martin J Kings software MathCad. That software is unfortunately not available anymore due to misuse by comercial users. The work has then continued in Hornresp, which is a great software, with almost the same result. The filling calculations are based on somewhat slightly different methods in the two softwares which create the slight differencies in outcome. The results has been explored back and forth and ended up with minor changes but pretty much the same as from the beginning with Paul and MathCad.
For midbass a number of Seas, SB Accoustic and ScanSpeak drivers has been up for discussion, exploration and design ending up with the by many highly appreciated SS D8531G00. The SB Accoustic SB17NRX2 (or MFC) will do as a budget alternative with minor changes to the design (according to simulations both in MathCad and Hornresp).
For the tweeter there could be a number of alternatives, up to high cost super tweeters. Although bot in comersial speakers as well as in the DIY world the mid price section seem to offer a number of very good alternatives from Seas, SB Accoustic, Peerless and ScanSpeak. Following the diyaudio Elsinore project for many years including the comparison of different tweeters there, I ended up with the SS D2608/91300 together with a waveguide as a starting point. This also very much from building one pair of Elsinores, helping a friend with one pair, and still having some pairs of wave guides in the basement. Hopefully it´s also where it will end up. The Elsinore is a 2,5 way speaker with a higher XO point to the tweeter. But hopefully the tweeter/WG combination will work with the lower X/O point in this design.
The basics looks like this:
- Mass loaded, Transmission Line (MLTL)
- Coupling chamber at the throat of the line(Inspiration Rauna Leira)
- Fairly simple 6/12 dB cross over (Xmachina + Xsim, Vituixcad)
- X/O point somewhere 2,3-2,8 kHz,
- Fairly standard/cheap components in the X/O (maybe except for one JA Superior Z-cap, the red one)
- 2 way with 2 drivers
- Tweeter SS D2608/91300
- Waveguide for the tweeter (from the Elsinore project here at Diyaudio)
- Midwoofer SS 18W/8531G00
- About 100 cm/40" in height, as narrow as possible
- Bass -3dB at about 32Hz Hz and -6dB at 28-29 Hz
- Partly tilted baffle
- Two versions - Four (std type of box) or six sided cabinet (inspiration Rauna Vale / Opus3 Chorus)
- MDF furniture quality, 25mm for the cabinet, 19 mm for the internal divider
- Cross over placed at the lower back of the cabinet for easy adjustments
- .......
The cross over will be based on actual measures with the drivers mounted in the cabinet. The measures will be done at different speaker positions (0,5 to 4 piradians). The software for the cross over will be explored with a number of supporting people, and softwares such Xmachina, Xsim and/or Vituixcad, REW and/or Arta etc.
Project started autumn 2020 and will continue slowly forward. Inspiration, comments, contributions etc are very welcome.
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Nice proejct concept and call to arms! 
I recently designed in Akabak, a 40in tall floorstaanding TL with the RS225-8 (~35hz bass extension). Although used with a ScanSpeak 10F/8424 - it could be adapted to a 3-way with a dome tweeter in a waveguide. I have had good success with an RST28F or RS28F in a commercially available Visaton WG300 waveguide too.
The resulting speaker has been built 4 going on 5 times and is one of the best speakers I have heard. A tapered TL is one of the best alignments, IMO. So good choice for your basic guideline requirement. This could be somme with dual 7in or dual 6.5in woofers like the SBA Papyrus with great results too.
More info here:
10F/8424 & RS225-8 FAST / WAW Ref Monitor
Measurements:
TL vent output only (attenuated to prevent mic clipping):
This is the simulation at Xmax which is reached at 21Vrms - for 100dB output:
I recently designed in Akabak, a 40in tall floorstaanding TL with the RS225-8 (~35hz bass extension). Although used with a ScanSpeak 10F/8424 - it could be adapted to a 3-way with a dome tweeter in a waveguide. I have had good success with an RST28F or RS28F in a commercially available Visaton WG300 waveguide too.
The resulting speaker has been built 4 going on 5 times and is one of the best speakers I have heard. A tapered TL is one of the best alignments, IMO. So good choice for your basic guideline requirement. This could be somme with dual 7in or dual 6.5in woofers like the SBA Papyrus with great results too.
More info here:
10F/8424 & RS225-8 FAST / WAW Ref Monitor
Measurements:
TL vent output only (attenuated to prevent mic clipping):
This is the simulation at Xmax which is reached at 21Vrms - for 100dB output:
Attachments
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Its as simple as that I would like to put in some of the preferences that I have found over the years into this design (se the list). PK (in combination with Dan) also has his Brioso. Fantastic speaker with the 8531, but not what I would like to design.
sorry, try this -
http://techtalk.parts-express.com/core/filedata/fetch?id=1411748&d=1556577207
Also a link from Rich Craig who did the crossover on the Facebook DIY speaker group -
DIY Loudspeaker Project Pad Public Group | Facebook
http://techtalk.parts-express.com/core/filedata/fetch?id=1411748&d=1556577207
Also a link from Rich Craig who did the crossover on the Facebook DIY speaker group -
DIY Loudspeaker Project Pad Public Group | Facebook
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Nice proejct concept and call to arms!
I recently designed in Akabak
Looks really neat. But once again - I really like to put my preferences together in one design.
I actually added two things to my original post here. The "driver chamber" and "simple pipe design". The chamber adds lower -F3 and some other things to the equation, and "simple pipe" is just to keep the wood work easy, and actually being able to design a floating tapering.
@sharkythe frog. Sorry for derailing your thread momentarily. You said your last speaker was Elsinore what were your impressions about it and how come you decided to dismantle it ? Reason I’m asking is that it has been on my list of future projects for awhile just can’t seem to get to it. Right now I’m in the process of finishing zaphs slightly modified ZRT 2.5 but there is a project after that already. Lol Looking forward to hearing your findings. Thx Peter
Neither of those two options really. What i did, as you can se in the sketch, was just "chamber" with a small step into the actual tapered pipe. It will be a part of the pipe (although not tapered), with the stepped transition into the tapered part. It actually changed the measures quite a bit. The idea came from a very well sounding speaker that I completely dismantled and rebuilt.
No problem. Maybe easier politically to ask here.
The Elsinores are fantastic speakers. If you are in doubt, don´t. To that I would also say stay with the original XO design from Joe. I built mine with the (extremely large) XO at the back of the cabinet to be able to play around with different combination of mods. The original was the best for me, except for changing the tweeter cap from 1,8 to 2,0. I also built a separate large base compartment under the speaker to hold a NewClassD 400w monoblock. Except for "being cool" (and a good way to get rid of the amp closures) it also raises the whole speaker 17 cm (7") up from the floor which improves the sound. Now they will replace a pair of Thiel/Accuton speakers in my basement in the movie room setup. The Thiel/Accuton are moving to one of my sons (another daddy support project).
It is also why I would like to use the Elsonore tweeter and waveguide here. They sound just great together.
Just go for it!!!
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Thx you for your opinion. I wasn’t gonna try to modify “that “ speaker which is exactly why I haven’t built it yet. Not a big fan of simple square enclosure. But after reading entire description files I found claims intriguing and interesting so maybe one day it will happen. Thx again and good luck with your best “last “ speaker which it never is.
Indeed it can.
The 'compression chamber' 'vents' into a parabolic 'closed cone', which in turn is offset 'open' pipe [duct] vented.
Resonances of open air columns
GM
Indeed it can! Here's my ~20 ft^3 14-500 Hz XO Dual Altec 515B 'subs' built in '69 : GM with Altec '''sub''' | GM210 | Flickr
: GM with Altec '''sub''' | GM210 | FlickrPROGRESS PROGRESS
Since the last post there has been quite some progress.
The cabinet is now a combination of inspiration from the OPUS3 Chorus (today Rauna Vale) and the Rauna Leira. Which mean a six sided cabinet with part of the front baffle tilted, and inside a coupling chamber connected to a straight line with a mass loading port. The drivers are currently thought to be ScanSpeaks, Midbass the 8531G00 and the tweeter the 2608 improved with the waveguide from the diyaudio Elsinores project.
Despite a little 1+ db dip at 100 Hz the response curve is great (run both in Hornresp and MathCad, and even better in the latter) and I have desided to live with it. All the rest of the dimensions measure great.
The six sided cabinet is a little more complicated to build. But who needs easy. It caters fo a stable build with less internal resonance (except for the annoying dip caused by the fairly fixed midbass driver position in the length of the line). Some birch wood rods will be drilled and glued stuck between a) the front and back baffles in the coupling chamber, b) front baffle and the internal divider, and c) the front baffle the divider and the back baffle at different hegihts. The great cad drawing is done by a diy fellow Neil B.
Since the last post there has been quite some progress.
The cabinet is now a combination of inspiration from the OPUS3 Chorus (today Rauna Vale) and the Rauna Leira. Which mean a six sided cabinet with part of the front baffle tilted, and inside a coupling chamber connected to a straight line with a mass loading port. The drivers are currently thought to be ScanSpeaks, Midbass the 8531G00 and the tweeter the 2608 improved with the waveguide from the diyaudio Elsinores project.
Despite a little 1+ db dip at 100 Hz the response curve is great (run both in Hornresp and MathCad, and even better in the latter) and I have desided to live with it. All the rest of the dimensions measure great.
The six sided cabinet is a little more complicated to build. But who needs easy. It caters fo a stable build with less internal resonance (except for the annoying dip caused by the fairly fixed midbass driver position in the length of the line). Some birch wood rods will be drilled and glued stuck between a) the front and back baffles in the coupling chamber, b) front baffle and the internal divider, and c) the front baffle the divider and the back baffle at different hegihts. The great cad drawing is done by a diy fellow Neil B.
Attachments
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Four and six sided versions
Building capapbilities differs among people. That mean that what some can build others cant. Therefore there are two different versions. The basic design idea is the same. Coupling chamber into a cylindrical line with a mass loading port in a cabinet with the upper part of the front baffle a little bit tilted.
The tweeter will have almost zero degrees listeing angle vertically, but will also get a liiiiitle more "space" with the help from the reflection from a ceiling.
Software exploration and measures it will probably tell us that there will be some differencies between the four and six sided versions of the XO due to difference in baffle reflections.
Building capapbilities differs among people. That mean that what some can build others cant. Therefore there are two different versions. The basic design idea is the same. Coupling chamber into a cylindrical line with a mass loading port in a cabinet with the upper part of the front baffle a little bit tilted.
The tweeter will have almost zero degrees listeing angle vertically, but will also get a liiiiitle more "space" with the help from the reflection from a ceiling.
Software exploration and measures it will probably tell us that there will be some differencies between the four and six sided versions of the XO due to difference in baffle reflections.
Attachments
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