Chris Roger's DIY Transmission Lines

[Martin213]

Discuss please........

Having recently aquired a very much previously loved pair of these 'classic' TL Monitors i would very much appreciate your opinions guys.....

IMHO they still 'sing',in there own way,despite the original design now being 34 years old! (OMG,it really was that long ago!!!)

The pair i proudly own now have been constantly modified,every time a mod became available,i have all the paperwork

In the 21st century,i'm sure with a few mods,they can still excel

One thing that confuses me is that in this reincarnation,a Morel MD32S is only used between 3.5k and 10k,where it crosses over to a super-tweeter to 21k

The Morel 32S can reach to 25k,so i'm confused

Please feel free to share your views and opinions...........

Kindest Regards

Martin

[Martin213]

BTW apparently they reach down to 23hz,it certainly feels like it

(actually i very much doubt my humble Rogers Cadet gets nearly that low,but at least our pics ain't fell off the wall yet,LOL!) :d

[Scottmoose]

Is that the Hifi Answers design?

BTW, I don't pretend to be an expert on drivers / XOs, but you don't always run a driver full-bandwidth. Most drivers have a greater bandwidth capacity than is utilised in complete speaker systems, primarily because although they might notionally have a couple of extra octaves extension, that doesn't necessarily mean they'll do it with much aplomb. In this case, the supertweeter probably has a smoother response across the 10KHz+ regions than the Morel does, so it makes sense to use it, and roll the Morel off earlier.

[Richard]

Hi Martin

Yes, my q too, are these the Answers ones from Peter or the later Pro9TLs? I have both original articles and will have a look at the rationale, but what Scottmoose says is certainly true about not running domes nearer than a couple of octaves from resonance.

[Martin213]

Hi Scott,Richard,
They are PeterJ's HFN&RR examples,but what puzzles me is that Ivan Leslie rates the MDT32S highly,used full range in his S5TL's.
Surely then the supertweeter is best used above,say,20k?

[Martin213]

I say HFN&RR because that's what it says on the folder containing all the paperwork,i suppose it could be Hi-Fi Answers

[Laz Baz]

Originally Posted by Martin213

BTW apparently they reach down to 23hz,it certainly feels like it

(actually i very much doubt my humble Rogers Cadet gets nearly that low,but at least our pics ain't fell off the wall yet,LOL!) :d

I am only just catching up with TL speakers. I started with TLS50 MkII and now I have a pair of IMF TLS 80 Mk II. It goes down to 19Hz.
I love the natural bass sound coming through them. I have a few CDs that I enjoy.

Do you lot have any CDs you could list that go real low-orgam music or other?

[psyclops]

I bought a pair of the Hi-Fi Answers models in about 1973 and have carted them all over the world since. I have just built another pair using the B139, B110, T27, Coles 4001G and the Faconaccoustics Super X-overs. There is a noticeable improvement. The older pair now reside alongside the TV making that sound better.

Modern CDs making an impression on me with bass reproduction are Neil Diamond's "Dreams" and Hugh Laurie's "Let them Talk." Am now listening to all the CDs and noticing improvement.

I'm wondering if anyone has tried substituting the Butterworth T27 tweeter section of the KEF 104aB crossover into the Atkinson crossover.

It's supposed to have better transient response, less HF rolloff and sound superior to the 3rd order type used in the 104 original version and perhaps the Atkinson.

I use a similar crossover to the Atkinson in my DIY ETI KEF transmission line speakers (using B139, B110 and T27A only). I've always found the midrange a bit forward and wonder what the effect on the sound the mods to the mid circuit as described earlier in the thread by ParsDJ (moving the 0.5mH inductor and the 2ohm resistor to the + side of the B110) would be. My ETI versions have them on the - side as per the unaltered circuit diagram.

I'm currently rebuilding the crossovers so any opinions would be appreciated.

104aB crossover below: