Assumming the Sketchup work is yours — you certainly have a better facility with SketchUp than i do… maybe partly due to a newer version, or the full version. I just import my 2D drawings extrude and assemble.
On both, except for the first angled bit behind the driver, the 45° deflectors are counterproductive,
Neither of the lines take advantage — and it is significant — of off-setting the driver from the start of the line. Martin’s tables do not cover end-loaded lines, so given your comment 3 posts earlier about Martin’s formulas it is not clear where these are coming from.
The 1st line looks kinda long, but that could be because i am more used to ML-TLs.
The 2nd line is kinda strange, It bifurcates, and looks like th eline doubles in size after the bifurcation. It is also not clear whether the lines are the same length. From one opening to the other, ignoring the stubm the both will act as a half-wave line. This one really needs a good modeller. I’d have to ask Scott how it would be repesented in MJK’s sheets.
Did you see this thread: Alpair 6M for Cyburgs Needle / BR M.A. Design
dave
On both, except for the first angled bit behind the driver, the 45° deflectors are counterproductive,
Neither of the lines take advantage — and it is significant — of off-setting the driver from the start of the line. Martin’s tables do not cover end-loaded lines, so given your comment 3 posts earlier about Martin’s formulas it is not clear where these are coming from.
The 1st line looks kinda long, but that could be because i am more used to ML-TLs.
The 2nd line is kinda strange, It bifurcates, and looks like th eline doubles in size after the bifurcation. It is also not clear whether the lines are the same length. From one opening to the other, ignoring the stubm the both will act as a half-wave line. This one really needs a good modeller. I’d have to ask Scott how it would be repesented in MJK’s sheets.
Did you see this thread: Alpair 6M for Cyburgs Needle / BR M.A. Design
dave
1) The Sketchup work is mine. Trying to kick off the channel in the hope that it might inspire or help people who seem to struggle with the hole idea of t-lines, be it in home audio or car audio.
I built my first t-line when back in 1990 ... '91 maybe. not to say I know everything there is to know, far from it, I'm always learning!
I've read a few papers since the 90's including Martin's. In the past I've also used software including leonards audio transmission line software, hornresp and the like. Whilst I do appreciate the hard work gone into such programs I always struggled with the results which were a mixed bag. I'm not wholly convinced by the 'Perfect' graph. Even cr@p speakers can have a flat response graph! 2) I've already got my Mark Audio CHN-70's in linear t-line 3x4" cardboard enclosure (I don't have a workshop at the moment), but they hit really deep when provoked. I was watching Wonder Woman (don't laugh) the other night and the little 4" CHN-70 really did kick in the lower octaves! It took be by surprise because I've found few tracks in music that make them shine the way that they do with films. But i guess that's a topic for another occasion.
I would say the aim is to achieve something like this, (YouTube link below) but I've already got there with my mock-up cardboard t-line
YouTube
3) The dual t-line is a concept I'm working on, and yes the lines are of different length. In one previous post there was a slight concern about placing drivers at different points along the line, but for me its no different than that of any speaker with multiple drivers. If a speaker is using two or three midbass driver for example, naturally one driver is going to be closer to the throat than the other(s), I can't see how one can get around it. So I don't lose any sleep over it, it is what it is!
I've never got into horns, but for now i'm dealing with what i know best. But I certainly don't rule out a horn enclosure in the future. Not against ported either, but for me, I had better luck with t-lines.
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Hi Matt
Sounds like you've put in a lot of work on these, i hope you get some workshop time soon and can build them up!
That's the goal, then I can leave this virtual world behind
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I'm not sure if you ended up with the CHN's - but I would say that Chris was being overly diplomatic when he said not everyone likes their flavour. It's like taking a drill bit to your ear in my experience.
The microcastle build is good. I made my own variation of it here: MARTELLO-2, a mini-tower from a single 2' x 4' but I would recommend to following the original design from Dave over mine because I think mine is a little on the narrow side for best driver breathability. Otherwise all is good!
In my build I used the EL-70. That driver is OBS now but you could use the CHP-70 or CHR-70. I have no experience with these two, but the published data and on-line experiences seem to be positive.
The microcastle build is good. I made my own variation of it here: MARTELLO-2, a mini-tower from a single 2' x 4' but I would recommend to following the original design from Dave over mine because I think mine is a little on the narrow side for best driver breathability. Otherwise all is good!
In my build I used the EL-70. That driver is OBS now but you could use the CHP-70 or CHR-70. I have no experience with these two, but the published data and on-line experiences seem to be positive.
Yes I did and I'm more than please with them. I don't expect miracles from a 3.5" driver, but they caught me by surprise whilst listening to movies. I do have them in a makeshift t-line enclosure and designed to hit into the lower 40's, but they are amazing little drivers. They sound more open than my Monitor Audio BX2 speakers @ £250 .. 300!
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