[Oz_Audio]

Sorry, I have been missing from this forum, but things have been happening out of my control and I have not had (really sitill don't have) time to make observations on our listening pleasure.

I have been reading in interest the various discussions on speakers to use with our beloved AKSA's especially the Orion, Aon and other active speaker systems.

I have devoured SL site over the passed 5 years and always read his deliberations on speaker design.

I find it interesting that he and others, Aon are now advocating a rear tweeter.  Is this now fashion or does it improve sound?

I have no idea what Hughs new Transmission Line speaker will be, but I am sure they will be very goos as I have heard the AKSonics at the AKSAfest in Sydney all those years ago.

Anyway, back to the subject at hand!

About 5 years ago, just after I built my 55 AKSA, (which unfortunately is still stock standard, I have a Nirvana Plus Kit on the shelf that I have not fitted yet), I needed new speakers to make the most of the AKSA.

As a DIY person, as most of you all here are, I spent afew months on the web reading and studying various speaker designs where I came across SL's site and others.

I have always liked the speed of Transmission Line speakers and I found Dave Dlugos's site http://www.t-linespeakers.org/index.html which is very informative and descided to build the TLb in Projects http://www.t-linespeakers.org/projects/tlB/index.html

As this speaker was very cheep to build and it used the mid-woofer drivers from the Ariel speaker, I thought it was a no brainer if it sounded terrible.

Well, 5 years ago, I built them, added a single SL Phoenix woofa using 2, 12" Peerless XLS and I have been privileged to be in Hi Fi Nirvana.

I still have not heard a better system no matter the price or brand.

Now, what has this got to do in an Amplifier Forum?

Well, hugh is working on multiple amps for the Orion or others and this route is expensive, not so much for Hugh's amps, but the Orions are probably over AUS$3000 to build on their own here in Australia and possibly othe countries as well.

If this is a path you are looking at, may I humbly suggest you try the TLb as a proof of concept, build the amps, then if you still want to go Orions, the TLb can be easily used as surrounds in a multi speaker system.

I have had afew people contact me asking for advise on these speakers, which I have gladly given, but none have come back to me with results.

As far as I know, I may be the only person to build these as they go against every speaker law in existance as some may not want to try something completely different.

So, If anyone does want to try them, they cost me a total of AUS$650 as I used US$35 capacitors in the crossover, (actually a single Cap is the only part of the crossover), I will give you whatever help is needed to go down the bi-amp or tri-amp active system.

As I have been enjoying these speakers for the past 5 years with my ols AKSA, I would love some feed back to the sound they make to keep my mind at ease that I am not completely mad to evangelistically proclaim these diminutive speakers.  And yes, I will fit the Nirvana plus!!!

Regards Mark

[rabbitz]

Hi Mark

Firstly, do fit the N+ upgrade as it's well worth it and be prepared for 100 hours+ run in of the BG caps. My 55N+ still marches on and have no urge to replace it but hasn't stopped me from building different amps.... other forces have stopped me.

The TLb is a great loudspeaker and was the inspiration for a little reference speaker at diyAudio and more info can be found here on the monople design..... http://www.rzaudio.com/rz52/diy_vifa.htm.

No, you are not going nuts as the Vifa P13 has some magic qualities and using them in a bipolar and TL makes things even better. The top end may be a bit better using the SEAS 27TDFC but I haven't tried it and I have no complaints with the Vifa D27TG I used (there was reports of a bad screaming batch around 2004). The originator of the diyAudio thread also built the TLb and was amazed by it's capabilities but preferred an active crossover rather than the single cap.

I also feel you can do better than the single cap crossover and that has been confirmed by others who have tried the crossovers shown here.... http://www.rzaudio.com/rz52/diy_vifa_xo.htm. The opinion is that Alt 3 is the best, followed by Alt 1 (that's the one I use). The single cap IMO was not as good, but I was using monopoles and all these crossovers are to suit that style of speaker and not the TLb.

The rear firing tweeter is nothing new and the best speaker I have ever heard (Infinity IRS mid 80's) used rear firing tweeters and mids in an OB. Most true OB dipoles I have heard could benefit from the rear firing tweeter to add to the higher levels of mids that this design creates, or padding of the mid woofer which has a benefit of raising the driver Qts so it goes lower (if required) in the OB design.

If you've found the sweet sound, stick with it and don't question it.... just enjoy, plus you've saved a lot of dollars in the process.
 

[Oz_Audio]

Thanks for the reply rabbitz,  Good to hear other people have been inspired to build this speaker and experiment with it.

I have brought up this speaker on other sites and most people are used to the conventional speaker design in crossovers and arrangement, and they all suggest trying a more conventional crossover.  Yes, I have tried other tweeters and crossovers, but nothing compares to the single cap, a 10uf from http://www.northcreekmusic.com/CrescendoSpeakerCaps.html

They don't make the 10uf any more, but they can be cascaded to get the same value.  Something I will be trying later this year, but to do this properly will cost a small fortune, but the end result will be worth it.  It will be interesting to compare.

I am only suggesting this here as they work exceptionally well with the AKSA and they are cheep to make and experiment with for active sub design.

Unfortunately other active speakers I have listened, to the detail is exceptional, but the life has been killed and they do not image very well.

A few years ago, my wife and I where watching the Grammies on free to air analogue TV through our GK1 (Siemens Gold Pin 7308), AKSA 55 and TLb speakers.  A live performace by Yo Yo Ma and a guitarist was showing, it could have been James Taylor (I can't remember) and we both noticed the the imaging of the 2 performers was being relayed into our lounge room.  Yo Yo Ma and James Tayler where 3 feet apart and we could hear the movement in our living room as they moved on the TV.

This type if imaging is exceptional and I put it down to Hughs electronics and the ability of the TLb with these very expensive Caps.  All parts are working in harmony so the sum is greater than the parts involved.

As I said, these are unconventional and we are becoming as a whole more conventional and not experimenting as was the case in the 50's, 60's and 70's.

Mark

[rabbitz]

Yes, I have tried other tweeters and crossovers, but nothing compares to the single cap, a 10uf from http://www.northcreekmusic.com/CrescendoSpeakerCaps.html

Ah... but have you tried a simple series crossover instead of parallel?

Active xo's have their place, especially for crossing over the woofers, but most I have heard have not been a total success. They are certainly not the easiest to get right even though a lot of builders say they are just that... easy, but some have a gift in getting them right.... we all make our choices in this game and if you like active and it works, fine, and the same applies for fans of passive. I believe passive crossovers have a lot of life in them yet, I find them easier to work with, plus have the benefit of less power amps required and so on. For my mains I let the active do the bass, but the mid-woofer and tweeter are passive between the 2 drivers and the mid-woofer rolls off naturally at the bottom end giving a nice acoustic crossover to the woofer which is a side benefit of a pseudo OB design.

If you need 10uF you can always run caps in parallel, but you knew that.

I blame a lot of the conventional mindset on the onward march of home theatre as you don't need to sell great speakers to the masses any more.... just try and find a good CD source these days.... it's very limited